1 # SPDX-License-Identifier: GPL-2.0
4 bool "64-bit kernel" if "$(ARCH)" = "x86"
5 default "$(ARCH)" != "i386"
7 Say yes to build a 64-bit kernel - formerly known as x86_64
8 Say no to build a 32-bit kernel - formerly known as i386
13 # Options that are inherently 32-bit kernel only:
14 select ARCH_WANT_IPC_PARSE_VERSION
16 select CLONE_BACKWARDS
17 select HAVE_DEBUG_STACKOVERFLOW
18 select MODULES_USE_ELF_REL
20 select GENERIC_VDSO_32
21 select ARCH_SPLIT_ARG64
26 # Options that are inherently 64-bit kernel only:
27 select ARCH_HAS_GIGANTIC_PAGE
28 select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
29 select ARCH_USE_CMPXCHG_LOCKREF
30 select HAVE_ARCH_SOFT_DIRTY
31 select MODULES_USE_ELF_RELA
32 select NEED_DMA_MAP_STATE
35 config FORCE_DYNAMIC_FTRACE
38 depends on FUNCTION_TRACER
41 We keep the static function tracing (!DYNAMIC_FTRACE) around
42 in order to test the non static function tracing in the
43 generic code, as other architectures still use it. But we
44 only need to keep it around for x86_64. No need to keep it
45 for x86_32. For x86_32, force DYNAMIC_FTRACE.
49 # ( Note that options that are marked 'if X86_64' could in principle be
50 # ported to 32-bit as well. )
55 # Note: keep this list sorted alphabetically
57 select ACPI_LEGACY_TABLES_LOOKUP if ACPI
58 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
59 select ARCH_32BIT_OFF_T if X86_32
60 select ARCH_CONFIGURES_CPU_MITIGATIONS
61 select ARCH_CLOCKSOURCE_INIT
62 select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
63 select ARCH_HAS_CPU_FINALIZE_INIT
64 select ARCH_HAS_DEBUG_VIRTUAL
65 select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
66 select ARCH_HAS_DEVMEM_IS_ALLOWED
67 select ARCH_HAS_EARLY_DEBUG if KGDB
68 select ARCH_HAS_ELF_RANDOMIZE
69 select ARCH_HAS_FAST_MULTIPLIER
70 select ARCH_HAS_FILTER_PGPROT
71 select ARCH_HAS_FORTIFY_SOURCE
72 select ARCH_HAS_GCOV_PROFILE_ALL
73 select ARCH_HAS_KCOV if X86_64 && STACK_VALIDATION
74 select ARCH_HAS_MEM_ENCRYPT
75 select ARCH_HAS_MEMBARRIER_SYNC_CORE
76 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
77 select ARCH_HAS_PMEM_API if X86_64
78 select ARCH_HAS_PTE_DEVMAP if X86_64
79 select ARCH_HAS_PTE_SPECIAL
80 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
81 select ARCH_HAS_COPY_MC if X86_64
82 select ARCH_HAS_SET_MEMORY
83 select ARCH_HAS_SET_DIRECT_MAP
84 select ARCH_HAS_STRICT_KERNEL_RWX
85 select ARCH_HAS_STRICT_MODULE_RWX
86 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
87 select ARCH_HAS_SYSCALL_WRAPPER
88 select ARCH_HAS_UBSAN_SANITIZE_ALL
89 select ARCH_HAS_DEBUG_WX
90 select ARCH_HAVE_NMI_SAFE_CMPXCHG
91 select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
92 select ARCH_MIGHT_HAVE_PC_PARPORT
93 select ARCH_MIGHT_HAVE_PC_SERIO
95 select ARCH_SUPPORTS_ACPI
96 select ARCH_SUPPORTS_ATOMIC_RMW
97 select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
98 select ARCH_USE_BUILTIN_BSWAP
99 select ARCH_USE_QUEUED_RWLOCKS
100 select ARCH_USE_QUEUED_SPINLOCKS
101 select ARCH_USE_SYM_ANNOTATIONS
102 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
103 select ARCH_WANT_DEFAULT_BPF_JIT if X86_64
104 select ARCH_WANTS_DYNAMIC_TASK_STRUCT
105 select ARCH_WANT_HUGE_PMD_SHARE
106 select ARCH_WANT_LD_ORPHAN_WARN
107 select ARCH_WANTS_THP_SWAP if X86_64
108 select BUILDTIME_TABLE_SORT
110 select CLOCKSOURCE_VALIDATE_LAST_CYCLE
111 select CLOCKSOURCE_WATCHDOG
112 select DCACHE_WORD_ACCESS
113 select EDAC_ATOMIC_SCRUB
115 select GENERIC_CLOCKEVENTS
116 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
117 select GENERIC_CLOCKEVENTS_MIN_ADJUST
118 select GENERIC_CMOS_UPDATE
119 select GENERIC_CPU_AUTOPROBE
120 select GENERIC_CPU_VULNERABILITIES
121 select GENERIC_EARLY_IOREMAP
123 select GENERIC_FIND_FIRST_BIT
125 select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
126 select GENERIC_IRQ_MATRIX_ALLOCATOR if X86_LOCAL_APIC
127 select GENERIC_IRQ_MIGRATION if SMP
128 select GENERIC_IRQ_PROBE
129 select GENERIC_IRQ_RESERVATION_MODE
130 select GENERIC_IRQ_SHOW
131 select GENERIC_PENDING_IRQ if SMP
132 select GENERIC_PTDUMP
133 select GENERIC_SMP_IDLE_THREAD
134 select GENERIC_STRNCPY_FROM_USER
135 select GENERIC_STRNLEN_USER
136 select GENERIC_TIME_VSYSCALL
137 select GENERIC_GETTIMEOFDAY
138 select GENERIC_VDSO_TIME_NS
139 select GUP_GET_PTE_LOW_HIGH if X86_PAE
140 select HARDIRQS_SW_RESEND
141 select HARDLOCKUP_CHECK_TIMESTAMP if X86_64
142 select HAVE_ACPI_APEI if ACPI
143 select HAVE_ACPI_APEI_NMI if ACPI
144 select HAVE_ALIGNED_STRUCT_PAGE if SLUB
145 select HAVE_ARCH_AUDITSYSCALL
146 select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
147 select HAVE_ARCH_JUMP_LABEL
148 select HAVE_ARCH_JUMP_LABEL_RELATIVE
149 select HAVE_ARCH_KASAN if X86_64
150 select HAVE_ARCH_KASAN_VMALLOC if X86_64
151 select HAVE_ARCH_KGDB
152 select HAVE_ARCH_MMAP_RND_BITS if MMU
153 select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
154 select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT
155 select HAVE_ARCH_PREL32_RELOCATIONS
156 select HAVE_ARCH_SECCOMP_FILTER
157 select HAVE_ARCH_THREAD_STRUCT_WHITELIST
158 select HAVE_ARCH_STACKLEAK
159 select HAVE_ARCH_TRACEHOOK
160 select HAVE_ARCH_TRANSPARENT_HUGEPAGE
161 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
162 select HAVE_ARCH_USERFAULTFD_WP if X86_64 && USERFAULTFD
163 select HAVE_ARCH_VMAP_STACK if X86_64
164 select HAVE_ARCH_WITHIN_STACK_FRAMES
165 select HAVE_ASM_MODVERSIONS
166 select HAVE_CMPXCHG_DOUBLE
167 select HAVE_CMPXCHG_LOCAL
168 select HAVE_CONTEXT_TRACKING if X86_64
169 select HAVE_C_RECORDMCOUNT
170 select HAVE_DEBUG_KMEMLEAK
171 select HAVE_DMA_CONTIGUOUS
172 select HAVE_DYNAMIC_FTRACE
173 select HAVE_DYNAMIC_FTRACE_WITH_REGS
174 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
176 select HAVE_EFFICIENT_UNALIGNED_ACCESS
178 select HAVE_EXIT_THREAD
180 select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE
181 select HAVE_FTRACE_MCOUNT_RECORD
182 select HAVE_FUNCTION_GRAPH_TRACER
183 select HAVE_FUNCTION_TRACER
184 select HAVE_GCC_PLUGINS
185 select HAVE_HW_BREAKPOINT
187 select HAVE_IOREMAP_PROT
188 select HAVE_IRQ_TIME_ACCOUNTING
189 select HAVE_KERNEL_BZIP2
190 select HAVE_KERNEL_GZIP
191 select HAVE_KERNEL_LZ4
192 select HAVE_KERNEL_LZMA
193 select HAVE_KERNEL_LZO
194 select HAVE_KERNEL_XZ
195 select HAVE_KERNEL_ZSTD
197 select HAVE_KPROBES_ON_FTRACE
198 select HAVE_FUNCTION_ERROR_INJECTION
199 select HAVE_KRETPROBES
201 select HAVE_LIVEPATCH if X86_64
202 select HAVE_MIXED_BREAKPOINTS_REGS
203 select HAVE_MOD_ARCH_SPECIFIC
207 select HAVE_OPTPROBES
208 select HAVE_PCSPKR_PLATFORM
209 select HAVE_PERF_EVENTS
210 select HAVE_PERF_EVENTS_NMI
211 select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
213 select HAVE_PERF_REGS
214 select HAVE_PERF_USER_STACK_DUMP
215 select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
216 select HAVE_POSIX_CPU_TIMERS_TASK_WORK
217 select HAVE_REGS_AND_STACK_ACCESS_API
218 select HAVE_RELIABLE_STACKTRACE if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
219 select HAVE_FUNCTION_ARG_ACCESS_API
220 select HAVE_STACKPROTECTOR if CC_HAS_SANE_STACKPROTECTOR
221 select HAVE_STACK_VALIDATION if X86_64
222 select HAVE_STATIC_CALL
223 select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION
225 select HAVE_SYSCALL_TRACEPOINTS
226 select HAVE_UNSTABLE_SCHED_CLOCK
227 select HAVE_USER_RETURN_NOTIFIER
228 select HAVE_GENERIC_VDSO
229 select HOTPLUG_SMT if SMP
230 select IRQ_FORCED_THREADING
231 select NEED_SG_DMA_LENGTH
232 select PCI_DOMAINS if PCI
233 select PCI_LOCKLESS_CONFIG if PCI
236 select RTC_MC146818_LIB
239 select STACK_VALIDATION if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
240 select SYSCTL_EXCEPTION_TRACE
241 select THREAD_INFO_IN_TASK
242 select USER_STACKTRACE_SUPPORT
244 select HAVE_ARCH_KCSAN if X86_64
245 select X86_FEATURE_NAMES if PROC_FS
246 select PROC_PID_ARCH_STATUS if PROC_FS
247 imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
249 config INSTRUCTION_DECODER
251 depends on KPROBES || PERF_EVENTS || UPROBES
255 default "elf32-i386" if X86_32
256 default "elf64-x86-64" if X86_64
258 config LOCKDEP_SUPPORT
261 config STACKTRACE_SUPPORT
267 config ARCH_MMAP_RND_BITS_MIN
271 config ARCH_MMAP_RND_BITS_MAX
275 config ARCH_MMAP_RND_COMPAT_BITS_MIN
278 config ARCH_MMAP_RND_COMPAT_BITS_MAX
284 config GENERIC_ISA_DMA
286 depends on ISA_DMA_API
291 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
293 config GENERIC_BUG_RELATIVE_POINTERS
296 config ARCH_MAY_HAVE_PC_FDC
298 depends on ISA_DMA_API
300 config GENERIC_CALIBRATE_DELAY
303 config ARCH_HAS_CPU_RELAX
306 config ARCH_HAS_CACHE_LINE_SIZE
309 config ARCH_HAS_FILTER_PGPROT
312 config HAVE_SETUP_PER_CPU_AREA
315 config NEED_PER_CPU_EMBED_FIRST_CHUNK
318 config NEED_PER_CPU_PAGE_FIRST_CHUNK
321 config ARCH_HIBERNATION_POSSIBLE
324 config ARCH_SUSPEND_POSSIBLE
327 config ARCH_WANT_GENERAL_HUGETLB
336 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
339 config KASAN_SHADOW_OFFSET
342 default 0xdffffc0000000000
344 config HAVE_INTEL_TXT
346 depends on INTEL_IOMMU && ACPI
350 depends on X86_32 && SMP
354 depends on X86_64 && SMP
356 config ARCH_SUPPORTS_UPROBES
359 config FIX_EARLYCON_MEM
362 config DYNAMIC_PHYSICAL_MASK
365 config PGTABLE_LEVELS
367 default 5 if X86_5LEVEL
372 config CC_HAS_SANE_STACKPROTECTOR
374 default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
375 default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
377 We have to make sure stack protector is unconditionally disabled if
378 the compiler produces broken code or if it does not let us control
379 the segment on 32-bit kernels.
381 menu "Processor type and features"
384 bool "DMA memory allocation support" if EXPERT
387 DMA memory allocation support allows devices with less than 32-bit
388 addressing to allocate within the first 16MB of address space.
389 Disable if no such devices will be used.
394 bool "Symmetric multi-processing support"
396 This enables support for systems with more than one CPU. If you have
397 a system with only one CPU, say N. If you have a system with more
400 If you say N here, the kernel will run on uni- and multiprocessor
401 machines, but will use only one CPU of a multiprocessor machine. If
402 you say Y here, the kernel will run on many, but not all,
403 uniprocessor machines. On a uniprocessor machine, the kernel
404 will run faster if you say N here.
406 Note that if you say Y here and choose architecture "586" or
407 "Pentium" under "Processor family", the kernel will not work on 486
408 architectures. Similarly, multiprocessor kernels for the "PPro"
409 architecture may not work on all Pentium based boards.
411 People using multiprocessor machines who say Y here should also say
412 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
413 Management" code will be disabled if you say Y here.
415 See also <file:Documentation/x86/i386/IO-APIC.rst>,
416 <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
417 <http://www.tldp.org/docs.html#howto>.
419 If you don't know what to do here, say N.
421 config X86_FEATURE_NAMES
422 bool "Processor feature human-readable names" if EMBEDDED
425 This option compiles in a table of x86 feature bits and corresponding
426 names. This is required to support /proc/cpuinfo and a few kernel
427 messages. You can disable this to save space, at the expense of
428 making those few kernel messages show numeric feature bits instead.
433 bool "Support x2apic"
434 depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
436 This enables x2apic support on CPUs that have this feature.
438 This allows 32-bit apic IDs (so it can support very large systems),
439 and accesses the local apic via MSRs not via mmio.
441 If you don't know what to do here, say N.
444 bool "Enable MPS table" if ACPI || SFI
446 depends on X86_LOCAL_APIC
448 For old smp systems that do not have proper acpi support. Newer systems
449 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
453 depends on X86_GOLDFISH
455 config X86_CPU_RESCTRL
456 bool "x86 CPU resource control support"
457 depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
459 select PROC_CPU_RESCTRL if PROC_FS
461 Enable x86 CPU resource control support.
463 Provide support for the allocation and monitoring of system resources
466 Intel calls this Intel Resource Director Technology
467 (Intel(R) RDT). More information about RDT can be found in the
468 Intel x86 Architecture Software Developer Manual.
470 AMD calls this AMD Platform Quality of Service (AMD QoS).
471 More information about AMD QoS can be found in the AMD64 Technology
472 Platform Quality of Service Extensions manual.
478 bool "Support for big SMP systems with more than 8 CPUs"
481 This option is needed for the systems that have more than 8 CPUs.
483 config X86_EXTENDED_PLATFORM
484 bool "Support for extended (non-PC) x86 platforms"
487 If you disable this option then the kernel will only support
488 standard PC platforms. (which covers the vast majority of
491 If you enable this option then you'll be able to select support
492 for the following (non-PC) 32 bit x86 platforms:
493 Goldfish (Android emulator)
496 SGI 320/540 (Visual Workstation)
497 STA2X11-based (e.g. Northville)
498 Moorestown MID devices
500 If you have one of these systems, or if you want to build a
501 generic distribution kernel, say Y here - otherwise say N.
505 config X86_EXTENDED_PLATFORM
506 bool "Support for extended (non-PC) x86 platforms"
509 If you disable this option then the kernel will only support
510 standard PC platforms. (which covers the vast majority of
513 If you enable this option then you'll be able to select support
514 for the following (non-PC) 64 bit x86 platforms:
519 If you have one of these systems, or if you want to build a
520 generic distribution kernel, say Y here - otherwise say N.
522 # This is an alphabetically sorted list of 64 bit extended platforms
523 # Please maintain the alphabetic order if and when there are additions
525 bool "Numascale NumaChip"
527 depends on X86_EXTENDED_PLATFORM
530 depends on X86_X2APIC
531 depends on PCI_MMCONFIG
533 Adds support for Numascale NumaChip large-SMP systems. Needed to
534 enable more than ~168 cores.
535 If you don't have one of these, you should say N here.
539 select HYPERVISOR_GUEST
541 depends on X86_64 && PCI
542 depends on X86_EXTENDED_PLATFORM
545 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
546 supposed to run on these EM64T-based machines. Only choose this option
547 if you have one of these machines.
550 bool "SGI Ultraviolet"
552 depends on X86_EXTENDED_PLATFORM
555 depends on KEXEC_CORE
556 depends on X86_X2APIC
559 This option is needed in order to support SGI Ultraviolet systems.
560 If you don't have one of these, you should say N here.
562 # Following is an alphabetically sorted list of 32 bit extended platforms
563 # Please maintain the alphabetic order if and when there are additions
566 bool "Goldfish (Virtual Platform)"
567 depends on X86_EXTENDED_PLATFORM
569 Enable support for the Goldfish virtual platform used primarily
570 for Android development. Unless you are building for the Android
571 Goldfish emulator say N here.
574 bool "CE4100 TV platform"
576 depends on PCI_GODIRECT
577 depends on X86_IO_APIC
579 depends on X86_EXTENDED_PLATFORM
580 select X86_REBOOTFIXUPS
582 select OF_EARLY_FLATTREE
584 Select for the Intel CE media processor (CE4100) SOC.
585 This option compiles in support for the CE4100 SOC for settop
586 boxes and media devices.
589 bool "Intel MID platform support"
590 depends on X86_EXTENDED_PLATFORM
591 depends on X86_PLATFORM_DEVICES
593 depends on X86_64 || (PCI_GOANY && X86_32)
594 depends on X86_IO_APIC
600 select MFD_INTEL_MSIC
602 Select to build a kernel capable of supporting Intel MID (Mobile
603 Internet Device) platform systems which do not have the PCI legacy
604 interfaces. If you are building for a PC class system say N here.
606 Intel MID platforms are based on an Intel processor and chipset which
607 consume less power than most of the x86 derivatives.
609 config X86_INTEL_QUARK
610 bool "Intel Quark platform support"
612 depends on X86_EXTENDED_PLATFORM
613 depends on X86_PLATFORM_DEVICES
617 depends on X86_IO_APIC
622 Select to include support for Quark X1000 SoC.
623 Say Y here if you have a Quark based system such as the Arduino
624 compatible Intel Galileo.
626 config X86_INTEL_LPSS
627 bool "Intel Low Power Subsystem Support"
628 depends on X86 && ACPI && PCI
633 Select to build support for Intel Low Power Subsystem such as
634 found on Intel Lynxpoint PCH. Selecting this option enables
635 things like clock tree (common clock framework) and pincontrol
636 which are needed by the LPSS peripheral drivers.
638 config X86_AMD_PLATFORM_DEVICE
639 bool "AMD ACPI2Platform devices support"
644 Select to interpret AMD specific ACPI device to platform device
645 such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
646 I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
647 implemented under PINCTRL subsystem.
650 tristate "Intel SoC IOSF Sideband support for SoC platforms"
653 This option enables sideband register access support for Intel SoC
654 platforms. On these platforms the IOSF sideband is used in lieu of
655 MSR's for some register accesses, mostly but not limited to thermal
656 and power. Drivers may query the availability of this device to
657 determine if they need the sideband in order to work on these
658 platforms. The sideband is available on the following SoC products.
659 This list is not meant to be exclusive.
664 You should say Y if you are running a kernel on one of these SoC's.
666 config IOSF_MBI_DEBUG
667 bool "Enable IOSF sideband access through debugfs"
668 depends on IOSF_MBI && DEBUG_FS
670 Select this option to expose the IOSF sideband access registers (MCR,
671 MDR, MCRX) through debugfs to write and read register information from
672 different units on the SoC. This is most useful for obtaining device
673 state information for debug and analysis. As this is a general access
674 mechanism, users of this option would have specific knowledge of the
675 device they want to access.
677 If you don't require the option or are in doubt, say N.
680 bool "RDC R-321x SoC"
682 depends on X86_EXTENDED_PLATFORM
684 select X86_REBOOTFIXUPS
686 This option is needed for RDC R-321x system-on-chip, also known
688 If you don't have one of these chips, you should say N here.
690 config X86_32_NON_STANDARD
691 bool "Support non-standard 32-bit SMP architectures"
692 depends on X86_32 && SMP
693 depends on X86_EXTENDED_PLATFORM
695 This option compiles in the bigsmp and STA2X11 default
696 subarchitectures. It is intended for a generic binary
697 kernel. If you select them all, kernel will probe it one by
698 one and will fallback to default.
700 # Alphabetically sorted list of Non standard 32 bit platforms
702 config X86_SUPPORTS_MEMORY_FAILURE
704 # MCE code calls memory_failure():
706 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
707 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
708 depends on X86_64 || !SPARSEMEM
709 select ARCH_SUPPORTS_MEMORY_FAILURE
712 bool "STA2X11 Companion Chip Support"
713 depends on X86_32_NON_STANDARD && PCI
718 This adds support for boards based on the STA2X11 IO-Hub,
719 a.k.a. "ConneXt". The chip is used in place of the standard
720 PC chipset, so all "standard" peripherals are missing. If this
721 option is selected the kernel will still be able to boot on
722 standard PC machines.
725 tristate "Eurobraille/Iris poweroff module"
728 The Iris machines from EuroBraille do not have APM or ACPI support
729 to shut themselves down properly. A special I/O sequence is
730 needed to do so, which is what this module does at
733 This is only for Iris machines from EuroBraille.
737 config SCHED_OMIT_FRAME_POINTER
739 prompt "Single-depth WCHAN output"
742 Calculate simpler /proc/<PID>/wchan values. If this option
743 is disabled then wchan values will recurse back to the
744 caller function. This provides more accurate wchan values,
745 at the expense of slightly more scheduling overhead.
747 If in doubt, say "Y".
749 menuconfig HYPERVISOR_GUEST
750 bool "Linux guest support"
752 Say Y here to enable options for running Linux under various hyper-
753 visors. This option enables basic hypervisor detection and platform
756 If you say N, all options in this submenu will be skipped and
757 disabled, and Linux guest support won't be built in.
762 bool "Enable paravirtualization code"
764 This changes the kernel so it can modify itself when it is run
765 under a hypervisor, potentially improving performance significantly
766 over full virtualization. However, when run without a hypervisor
767 the kernel is theoretically slower and slightly larger.
772 config PARAVIRT_DEBUG
773 bool "paravirt-ops debugging"
774 depends on PARAVIRT && DEBUG_KERNEL
776 Enable to debug paravirt_ops internals. Specifically, BUG if
777 a paravirt_op is missing when it is called.
779 config PARAVIRT_SPINLOCKS
780 bool "Paravirtualization layer for spinlocks"
781 depends on PARAVIRT && SMP
783 Paravirtualized spinlocks allow a pvops backend to replace the
784 spinlock implementation with something virtualization-friendly
785 (for example, block the virtual CPU rather than spinning).
787 It has a minimal impact on native kernels and gives a nice performance
788 benefit on paravirtualized KVM / Xen kernels.
790 If you are unsure how to answer this question, answer Y.
792 config X86_HV_CALLBACK_VECTOR
795 source "arch/x86/xen/Kconfig"
798 bool "KVM Guest support (including kvmclock)"
800 select PARAVIRT_CLOCK
801 select ARCH_CPUIDLE_HALTPOLL
802 select X86_HV_CALLBACK_VECTOR
805 This option enables various optimizations for running under the KVM
806 hypervisor. It includes a paravirtualized clock, so that instead
807 of relying on a PIT (or probably other) emulation by the
808 underlying device model, the host provides the guest with
809 timing infrastructure such as time of day, and system time
811 config ARCH_CPUIDLE_HALTPOLL
813 prompt "Disable host haltpoll when loading haltpoll driver"
815 If virtualized under KVM, disable host haltpoll.
818 bool "Support for running PVH guests"
820 This option enables the PVH entry point for guest virtual machines
821 as specified in the x86/HVM direct boot ABI.
823 config PARAVIRT_TIME_ACCOUNTING
824 bool "Paravirtual steal time accounting"
827 Select this option to enable fine granularity task steal time
828 accounting. Time spent executing other tasks in parallel with
829 the current vCPU is discounted from the vCPU power. To account for
830 that, there can be a small performance impact.
832 If in doubt, say N here.
834 config PARAVIRT_CLOCK
837 config JAILHOUSE_GUEST
838 bool "Jailhouse non-root cell support"
839 depends on X86_64 && PCI
842 This option allows to run Linux as guest in a Jailhouse non-root
843 cell. You can leave this option disabled if you only want to start
844 Jailhouse and run Linux afterwards in the root cell.
847 bool "ACRN Guest support"
849 select X86_HV_CALLBACK_VECTOR
851 This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
852 a flexible, lightweight reference open-source hypervisor, built with
853 real-time and safety-criticality in mind. It is built for embedded
854 IOT with small footprint and real-time features. More details can be
855 found in https://projectacrn.org/.
857 endif #HYPERVISOR_GUEST
859 source "arch/x86/Kconfig.cpu"
863 prompt "HPET Timer Support" if X86_32
865 Use the IA-PC HPET (High Precision Event Timer) to manage
866 time in preference to the PIT and RTC, if a HPET is
868 HPET is the next generation timer replacing legacy 8254s.
869 The HPET provides a stable time base on SMP
870 systems, unlike the TSC, but it is more expensive to access,
871 as it is off-chip. The interface used is documented
872 in the HPET spec, revision 1.
874 You can safely choose Y here. However, HPET will only be
875 activated if the platform and the BIOS support this feature.
876 Otherwise the 8254 will be used for timing services.
878 Choose N to continue using the legacy 8254 timer.
880 config HPET_EMULATE_RTC
882 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
885 def_bool y if X86_INTEL_MID
886 prompt "Intel MID APB Timer Support" if X86_INTEL_MID
888 depends on X86_INTEL_MID && SFI
890 APB timer is the replacement for 8254, HPET on X86 MID platforms.
891 The APBT provides a stable time base on SMP
892 systems, unlike the TSC, but it is more expensive to access,
893 as it is off-chip. APB timers are always running regardless of CPU
894 C states, they are used as per CPU clockevent device when possible.
896 # Mark as expert because too many people got it wrong.
897 # The code disables itself when not needed.
900 select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
901 bool "Enable DMI scanning" if EXPERT
903 Enabled scanning of DMI to identify machine quirks. Say Y
904 here unless you have verified that your setup is not
905 affected by entries in the DMI blacklist. Required by PNP
909 bool "Old AMD GART IOMMU support"
913 depends on X86_64 && PCI && AMD_NB
915 Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
916 GART based hardware IOMMUs.
918 The GART supports full DMA access for devices with 32-bit access
919 limitations, on systems with more than 3 GB. This is usually needed
920 for USB, sound, many IDE/SATA chipsets and some other devices.
922 Newer systems typically have a modern AMD IOMMU, supported via
923 the CONFIG_AMD_IOMMU=y config option.
925 In normal configurations this driver is only active when needed:
926 there's more than 3 GB of memory and the system contains a
927 32-bit limited device.
932 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
933 depends on X86_64 && SMP && DEBUG_KERNEL
934 select CPUMASK_OFFSTACK
936 Enable maximum number of CPUS and NUMA Nodes for this architecture.
940 # The maximum number of CPUs supported:
942 # The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
943 # and which can be configured interactively in the
944 # [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
946 # The ranges are different on 32-bit and 64-bit kernels, depending on
947 # hardware capabilities and scalability features of the kernel.
949 # ( If MAXSMP is enabled we just use the highest possible value and disable
950 # interactive configuration. )
953 config NR_CPUS_RANGE_BEGIN
955 default NR_CPUS_RANGE_END if MAXSMP
959 config NR_CPUS_RANGE_END
962 default 64 if SMP && X86_BIGSMP
963 default 8 if SMP && !X86_BIGSMP
966 config NR_CPUS_RANGE_END
969 default 8192 if SMP && CPUMASK_OFFSTACK
970 default 512 if SMP && !CPUMASK_OFFSTACK
973 config NR_CPUS_DEFAULT
976 default 32 if X86_BIGSMP
980 config NR_CPUS_DEFAULT
983 default 8192 if MAXSMP
988 int "Maximum number of CPUs" if SMP && !MAXSMP
989 range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
990 default NR_CPUS_DEFAULT
992 This allows you to specify the maximum number of CPUs which this
993 kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
994 supported value is 8192, otherwise the maximum value is 512. The
995 minimum value which makes sense is 2.
997 This is purely to save memory: each supported CPU adds about 8KB
1005 prompt "Multi-core scheduler support"
1008 Multi-core scheduler support improves the CPU scheduler's decision
1009 making when dealing with multi-core CPU chips at a cost of slightly
1010 increased overhead in some places. If unsure say N here.
1012 config SCHED_MC_PRIO
1013 bool "CPU core priorities scheduler support"
1014 depends on SCHED_MC && CPU_SUP_INTEL
1015 select X86_INTEL_PSTATE
1019 Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1020 core ordering determined at manufacturing time, which allows
1021 certain cores to reach higher turbo frequencies (when running
1022 single threaded workloads) than others.
1024 Enabling this kernel feature teaches the scheduler about
1025 the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1026 scheduler's CPU selection logic accordingly, so that higher
1027 overall system performance can be achieved.
1029 This feature will have no effect on CPUs without this feature.
1031 If unsure say Y here.
1035 depends on !SMP && X86_LOCAL_APIC
1038 bool "Local APIC support on uniprocessors" if !PCI_MSI
1040 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1042 A local APIC (Advanced Programmable Interrupt Controller) is an
1043 integrated interrupt controller in the CPU. If you have a single-CPU
1044 system which has a processor with a local APIC, you can say Y here to
1045 enable and use it. If you say Y here even though your machine doesn't
1046 have a local APIC, then the kernel will still run with no slowdown at
1047 all. The local APIC supports CPU-generated self-interrupts (timer,
1048 performance counters), and the NMI watchdog which detects hard
1051 config X86_UP_IOAPIC
1052 bool "IO-APIC support on uniprocessors"
1053 depends on X86_UP_APIC
1055 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1056 SMP-capable replacement for PC-style interrupt controllers. Most
1057 SMP systems and many recent uniprocessor systems have one.
1059 If you have a single-CPU system with an IO-APIC, you can say Y here
1060 to use it. If you say Y here even though your machine doesn't have
1061 an IO-APIC, then the kernel will still run with no slowdown at all.
1063 config X86_LOCAL_APIC
1065 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1066 select IRQ_DOMAIN_HIERARCHY
1067 select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1071 depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1073 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1074 bool "Reroute for broken boot IRQs"
1075 depends on X86_IO_APIC
1077 This option enables a workaround that fixes a source of
1078 spurious interrupts. This is recommended when threaded
1079 interrupt handling is used on systems where the generation of
1080 superfluous "boot interrupts" cannot be disabled.
1082 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1083 entry in the chipset's IO-APIC is masked (as, e.g. the RT
1084 kernel does during interrupt handling). On chipsets where this
1085 boot IRQ generation cannot be disabled, this workaround keeps
1086 the original IRQ line masked so that only the equivalent "boot
1087 IRQ" is delivered to the CPUs. The workaround also tells the
1088 kernel to set up the IRQ handler on the boot IRQ line. In this
1089 way only one interrupt is delivered to the kernel. Otherwise
1090 the spurious second interrupt may cause the kernel to bring
1091 down (vital) interrupt lines.
1093 Only affects "broken" chipsets. Interrupt sharing may be
1094 increased on these systems.
1097 bool "Machine Check / overheating reporting"
1098 select GENERIC_ALLOCATOR
1101 Machine Check support allows the processor to notify the
1102 kernel if it detects a problem (e.g. overheating, data corruption).
1103 The action the kernel takes depends on the severity of the problem,
1104 ranging from warning messages to halting the machine.
1106 config X86_MCELOG_LEGACY
1107 bool "Support for deprecated /dev/mcelog character device"
1110 Enable support for /dev/mcelog which is needed by the old mcelog
1111 userspace logging daemon. Consider switching to the new generation
1114 config X86_MCE_INTEL
1116 prompt "Intel MCE features"
1117 depends on X86_MCE && X86_LOCAL_APIC
1119 Additional support for intel specific MCE features such as
1120 the thermal monitor.
1124 prompt "AMD MCE features"
1125 depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1127 Additional support for AMD specific MCE features such as
1128 the DRAM Error Threshold.
1130 config X86_ANCIENT_MCE
1131 bool "Support for old Pentium 5 / WinChip machine checks"
1132 depends on X86_32 && X86_MCE
1134 Include support for machine check handling on old Pentium 5 or WinChip
1135 systems. These typically need to be enabled explicitly on the command
1138 config X86_MCE_THRESHOLD
1139 depends on X86_MCE_AMD || X86_MCE_INTEL
1142 config X86_MCE_INJECT
1143 depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1144 tristate "Machine check injector support"
1146 Provide support for injecting machine checks for testing purposes.
1147 If you don't know what a machine check is and you don't do kernel
1148 QA it is safe to say n.
1150 config X86_THERMAL_VECTOR
1152 depends on X86_MCE_INTEL
1154 source "arch/x86/events/Kconfig"
1156 config X86_LEGACY_VM86
1157 bool "Legacy VM86 support"
1160 This option allows user programs to put the CPU into V8086
1161 mode, which is an 80286-era approximation of 16-bit real mode.
1163 Some very old versions of X and/or vbetool require this option
1164 for user mode setting. Similarly, DOSEMU will use it if
1165 available to accelerate real mode DOS programs. However, any
1166 recent version of DOSEMU, X, or vbetool should be fully
1167 functional even without kernel VM86 support, as they will all
1168 fall back to software emulation. Nevertheless, if you are using
1169 a 16-bit DOS program where 16-bit performance matters, vm86
1170 mode might be faster than emulation and you might want to
1173 Note that any app that works on a 64-bit kernel is unlikely to
1174 need this option, as 64-bit kernels don't, and can't, support
1175 V8086 mode. This option is also unrelated to 16-bit protected
1176 mode and is not needed to run most 16-bit programs under Wine.
1178 Enabling this option increases the complexity of the kernel
1179 and slows down exception handling a tiny bit.
1181 If unsure, say N here.
1185 default X86_LEGACY_VM86
1188 bool "Enable support for 16-bit segments" if EXPERT
1190 depends on MODIFY_LDT_SYSCALL
1192 This option is required by programs like Wine to run 16-bit
1193 protected mode legacy code on x86 processors. Disabling
1194 this option saves about 300 bytes on i386, or around 6K text
1195 plus 16K runtime memory on x86-64,
1199 depends on X86_16BIT && X86_32
1203 depends on X86_16BIT && X86_64
1205 config X86_VSYSCALL_EMULATION
1206 bool "Enable vsyscall emulation" if EXPERT
1210 This enables emulation of the legacy vsyscall page. Disabling
1211 it is roughly equivalent to booting with vsyscall=none, except
1212 that it will also disable the helpful warning if a program
1213 tries to use a vsyscall. With this option set to N, offending
1214 programs will just segfault, citing addresses of the form
1217 This option is required by many programs built before 2013, and
1218 care should be used even with newer programs if set to N.
1220 Disabling this option saves about 7K of kernel size and
1221 possibly 4K of additional runtime pagetable memory.
1223 config X86_IOPL_IOPERM
1224 bool "IOPERM and IOPL Emulation"
1227 This enables the ioperm() and iopl() syscalls which are necessary
1228 for legacy applications.
1230 Legacy IOPL support is an overbroad mechanism which allows user
1231 space aside of accessing all 65536 I/O ports also to disable
1232 interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1233 capabilities and permission from potentially active security
1236 The emulation restricts the functionality of the syscall to
1237 only allowing the full range I/O port access, but prevents the
1238 ability to disable interrupts from user space which would be
1239 granted if the hardware IOPL mechanism would be used.
1242 tristate "Toshiba Laptop support"
1245 This adds a driver to safely access the System Management Mode of
1246 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1247 not work on models with a Phoenix BIOS. The System Management Mode
1248 is used to set the BIOS and power saving options on Toshiba portables.
1250 For information on utilities to make use of this driver see the
1251 Toshiba Linux utilities web site at:
1252 <http://www.buzzard.org.uk/toshiba/>.
1254 Say Y if you intend to run this kernel on a Toshiba portable.
1258 tristate "Dell i8k legacy laptop support"
1261 select SENSORS_DELL_SMM
1263 This option enables legacy /proc/i8k userspace interface in hwmon
1264 dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1265 temperature and allows controlling fan speeds of Dell laptops via
1266 System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1267 it reports also power and hotkey status. For fan speed control is
1268 needed userspace package i8kutils.
1270 Say Y if you intend to run this kernel on old Dell laptops or want to
1271 use userspace package i8kutils.
1274 config X86_REBOOTFIXUPS
1275 bool "Enable X86 board specific fixups for reboot"
1278 This enables chipset and/or board specific fixups to be done
1279 in order to get reboot to work correctly. This is only needed on
1280 some combinations of hardware and BIOS. The symptom, for which
1281 this config is intended, is when reboot ends with a stalled/hung
1284 Currently, the only fixup is for the Geode machines using
1285 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1287 Say Y if you want to enable the fixup. Currently, it's safe to
1288 enable this option even if you don't need it.
1292 bool "CPU microcode loading support"
1294 depends on CPU_SUP_AMD || CPU_SUP_INTEL
1296 If you say Y here, you will be able to update the microcode on
1297 Intel and AMD processors. The Intel support is for the IA32 family,
1298 e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1299 AMD support is for families 0x10 and later. You will obviously need
1300 the actual microcode binary data itself which is not shipped with
1303 The preferred method to load microcode from a detached initrd is described
1304 in Documentation/x86/microcode.rst. For that you need to enable
1305 CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1306 initrd for microcode blobs.
1308 In addition, you can build the microcode into the kernel. For that you
1309 need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1312 config MICROCODE_INTEL
1313 bool "Intel microcode loading support"
1314 depends on CPU_SUP_INTEL && MICROCODE
1317 This options enables microcode patch loading support for Intel
1320 For the current Intel microcode data package go to
1321 <https://downloadcenter.intel.com> and search for
1322 'Linux Processor Microcode Data File'.
1324 config MICROCODE_AMD
1325 bool "AMD microcode loading support"
1326 depends on CPU_SUP_AMD && MICROCODE
1328 If you select this option, microcode patch loading support for AMD
1329 processors will be enabled.
1331 config MICROCODE_LATE_LOADING
1332 bool "Late microcode loading (DANGEROUS)"
1334 depends on MICROCODE
1336 Loading microcode late, when the system is up and executing instructions
1337 is a tricky business and should be avoided if possible. Just the sequence
1338 of synchronizing all cores and SMT threads is one fragile dance which does
1339 not guarantee that cores might not softlock after the loading. Therefore,
1340 use this at your own risk. Late loading taints the kernel too.
1343 tristate "/dev/cpu/*/msr - Model-specific register support"
1345 This device gives privileged processes access to the x86
1346 Model-Specific Registers (MSRs). It is a character device with
1347 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1348 MSR accesses are directed to a specific CPU on multi-processor
1352 tristate "/dev/cpu/*/cpuid - CPU information support"
1354 This device gives processes access to the x86 CPUID instruction to
1355 be executed on a specific processor. It is a character device
1356 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1360 prompt "High Memory Support"
1367 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1368 However, the address space of 32-bit x86 processors is only 4
1369 Gigabytes large. That means that, if you have a large amount of
1370 physical memory, not all of it can be "permanently mapped" by the
1371 kernel. The physical memory that's not permanently mapped is called
1374 If you are compiling a kernel which will never run on a machine with
1375 more than 1 Gigabyte total physical RAM, answer "off" here (default
1376 choice and suitable for most users). This will result in a "3GB/1GB"
1377 split: 3GB are mapped so that each process sees a 3GB virtual memory
1378 space and the remaining part of the 4GB virtual memory space is used
1379 by the kernel to permanently map as much physical memory as
1382 If the machine has between 1 and 4 Gigabytes physical RAM, then
1385 If more than 4 Gigabytes is used then answer "64GB" here. This
1386 selection turns Intel PAE (Physical Address Extension) mode on.
1387 PAE implements 3-level paging on IA32 processors. PAE is fully
1388 supported by Linux, PAE mode is implemented on all recent Intel
1389 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1390 then the kernel will not boot on CPUs that don't support PAE!
1392 The actual amount of total physical memory will either be
1393 auto detected or can be forced by using a kernel command line option
1394 such as "mem=256M". (Try "man bootparam" or see the documentation of
1395 your boot loader (lilo or loadlin) about how to pass options to the
1396 kernel at boot time.)
1398 If unsure, say "off".
1403 Select this if you have a 32-bit processor and between 1 and 4
1404 gigabytes of physical RAM.
1408 depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1411 Select this if you have a 32-bit processor and more than 4
1412 gigabytes of physical RAM.
1417 prompt "Memory split" if EXPERT
1421 Select the desired split between kernel and user memory.
1423 If the address range available to the kernel is less than the
1424 physical memory installed, the remaining memory will be available
1425 as "high memory". Accessing high memory is a little more costly
1426 than low memory, as it needs to be mapped into the kernel first.
1427 Note that increasing the kernel address space limits the range
1428 available to user programs, making the address space there
1429 tighter. Selecting anything other than the default 3G/1G split
1430 will also likely make your kernel incompatible with binary-only
1433 If you are not absolutely sure what you are doing, leave this
1437 bool "3G/1G user/kernel split"
1438 config VMSPLIT_3G_OPT
1440 bool "3G/1G user/kernel split (for full 1G low memory)"
1442 bool "2G/2G user/kernel split"
1443 config VMSPLIT_2G_OPT
1445 bool "2G/2G user/kernel split (for full 2G low memory)"
1447 bool "1G/3G user/kernel split"
1452 default 0xB0000000 if VMSPLIT_3G_OPT
1453 default 0x80000000 if VMSPLIT_2G
1454 default 0x78000000 if VMSPLIT_2G_OPT
1455 default 0x40000000 if VMSPLIT_1G
1461 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1464 bool "PAE (Physical Address Extension) Support"
1465 depends on X86_32 && !HIGHMEM4G
1466 select PHYS_ADDR_T_64BIT
1469 PAE is required for NX support, and furthermore enables
1470 larger swapspace support for non-overcommit purposes. It
1471 has the cost of more pagetable lookup overhead, and also
1472 consumes more pagetable space per process.
1475 bool "Enable 5-level page tables support"
1477 select DYNAMIC_MEMORY_LAYOUT
1478 select SPARSEMEM_VMEMMAP
1481 5-level paging enables access to larger address space:
1482 upto 128 PiB of virtual address space and 4 PiB of
1483 physical address space.
1485 It will be supported by future Intel CPUs.
1487 A kernel with the option enabled can be booted on machines that
1488 support 4- or 5-level paging.
1490 See Documentation/x86/x86_64/5level-paging.rst for more
1495 config X86_DIRECT_GBPAGES
1499 Certain kernel features effectively disable kernel
1500 linear 1 GB mappings (even if the CPU otherwise
1501 supports them), so don't confuse the user by printing
1502 that we have them enabled.
1504 config X86_CPA_STATISTICS
1505 bool "Enable statistic for Change Page Attribute"
1508 Expose statistics about the Change Page Attribute mechanism, which
1509 helps to determine the effectiveness of preserving large and huge
1510 page mappings when mapping protections are changed.
1512 config AMD_MEM_ENCRYPT
1513 bool "AMD Secure Memory Encryption (SME) support"
1514 depends on X86_64 && CPU_SUP_AMD
1515 select DMA_COHERENT_POOL
1516 select DYNAMIC_PHYSICAL_MASK
1517 select ARCH_USE_MEMREMAP_PROT
1518 select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1519 select INSTRUCTION_DECODER
1520 select ARCH_HAS_CC_PLATFORM
1522 Say yes to enable support for the encryption of system memory.
1523 This requires an AMD processor that supports Secure Memory
1526 config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1527 bool "Activate AMD Secure Memory Encryption (SME) by default"
1528 depends on AMD_MEM_ENCRYPT
1530 Say yes to have system memory encrypted by default if running on
1531 an AMD processor that supports Secure Memory Encryption (SME).
1533 If set to Y, then the encryption of system memory can be
1534 deactivated with the mem_encrypt=off command line option.
1536 If set to N, then the encryption of system memory can be
1537 activated with the mem_encrypt=on command line option.
1539 # Common NUMA Features
1541 bool "NUMA Memory Allocation and Scheduler Support"
1543 depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1544 default y if X86_BIGSMP
1546 Enable NUMA (Non-Uniform Memory Access) support.
1548 The kernel will try to allocate memory used by a CPU on the
1549 local memory controller of the CPU and add some more
1550 NUMA awareness to the kernel.
1552 For 64-bit this is recommended if the system is Intel Core i7
1553 (or later), AMD Opteron, or EM64T NUMA.
1555 For 32-bit this is only needed if you boot a 32-bit
1556 kernel on a 64-bit NUMA platform.
1558 Otherwise, you should say N.
1562 prompt "Old style AMD Opteron NUMA detection"
1563 depends on X86_64 && NUMA && PCI
1565 Enable AMD NUMA node topology detection. You should say Y here if
1566 you have a multi processor AMD system. This uses an old method to
1567 read the NUMA configuration directly from the builtin Northbridge
1568 of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1569 which also takes priority if both are compiled in.
1571 config X86_64_ACPI_NUMA
1573 prompt "ACPI NUMA detection"
1574 depends on X86_64 && NUMA && ACPI && PCI
1577 Enable ACPI SRAT based node topology detection.
1580 bool "NUMA emulation"
1583 Enable NUMA emulation. A flat machine will be split
1584 into virtual nodes when booted with "numa=fake=N", where N is the
1585 number of nodes. This is only useful for debugging.
1588 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1590 default "10" if MAXSMP
1591 default "6" if X86_64
1593 depends on NEED_MULTIPLE_NODES
1595 Specify the maximum number of NUMA Nodes available on the target
1596 system. Increases memory reserved to accommodate various tables.
1598 config ARCH_FLATMEM_ENABLE
1600 depends on X86_32 && !NUMA
1602 config ARCH_SPARSEMEM_ENABLE
1604 depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1605 select SPARSEMEM_STATIC if X86_32
1606 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1608 config ARCH_SPARSEMEM_DEFAULT
1609 def_bool X86_64 || (NUMA && X86_32)
1611 config ARCH_SELECT_MEMORY_MODEL
1613 depends on ARCH_SPARSEMEM_ENABLE
1615 config ARCH_MEMORY_PROBE
1616 bool "Enable sysfs memory/probe interface"
1617 depends on X86_64 && MEMORY_HOTPLUG
1619 This option enables a sysfs memory/probe interface for testing.
1620 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1621 If you are unsure how to answer this question, answer N.
1623 config ARCH_PROC_KCORE_TEXT
1625 depends on X86_64 && PROC_KCORE
1627 config ILLEGAL_POINTER_VALUE
1630 default 0xdead000000000000 if X86_64
1632 config X86_PMEM_LEGACY_DEVICE
1635 config X86_PMEM_LEGACY
1636 tristate "Support non-standard NVDIMMs and ADR protected memory"
1637 depends on PHYS_ADDR_T_64BIT
1639 select X86_PMEM_LEGACY_DEVICE
1640 select NUMA_KEEP_MEMINFO if NUMA
1643 Treat memory marked using the non-standard e820 type of 12 as used
1644 by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1645 The kernel will offer these regions to the 'pmem' driver so
1646 they can be used for persistent storage.
1651 bool "Allocate 3rd-level pagetables from highmem"
1654 The VM uses one page table entry for each page of physical memory.
1655 For systems with a lot of RAM, this can be wasteful of precious
1656 low memory. Setting this option will put user-space page table
1657 entries in high memory.
1659 config X86_CHECK_BIOS_CORRUPTION
1660 bool "Check for low memory corruption"
1662 Periodically check for memory corruption in low memory, which
1663 is suspected to be caused by BIOS. Even when enabled in the
1664 configuration, it is disabled at runtime. Enable it by
1665 setting "memory_corruption_check=1" on the kernel command
1666 line. By default it scans the low 64k of memory every 60
1667 seconds; see the memory_corruption_check_size and
1668 memory_corruption_check_period parameters in
1669 Documentation/admin-guide/kernel-parameters.rst to adjust this.
1671 When enabled with the default parameters, this option has
1672 almost no overhead, as it reserves a relatively small amount
1673 of memory and scans it infrequently. It both detects corruption
1674 and prevents it from affecting the running system.
1676 It is, however, intended as a diagnostic tool; if repeatable
1677 BIOS-originated corruption always affects the same memory,
1678 you can use memmap= to prevent the kernel from using that
1681 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1682 bool "Set the default setting of memory_corruption_check"
1683 depends on X86_CHECK_BIOS_CORRUPTION
1686 Set whether the default state of memory_corruption_check is
1689 config X86_RESERVE_LOW
1690 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1694 Specify the amount of low memory to reserve for the BIOS.
1696 The first page contains BIOS data structures that the kernel
1697 must not use, so that page must always be reserved.
1699 By default we reserve the first 64K of physical RAM, as a
1700 number of BIOSes are known to corrupt that memory range
1701 during events such as suspend/resume or monitor cable
1702 insertion, so it must not be used by the kernel.
1704 You can set this to 4 if you are absolutely sure that you
1705 trust the BIOS to get all its memory reservations and usages
1706 right. If you know your BIOS have problems beyond the
1707 default 64K area, you can set this to 640 to avoid using the
1708 entire low memory range.
1710 If you have doubts about the BIOS (e.g. suspend/resume does
1711 not work or there's kernel crashes after certain hardware
1712 hotplug events) then you might want to enable
1713 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1714 typical corruption patterns.
1716 Leave this to the default value of 64 if you are unsure.
1718 config MATH_EMULATION
1720 depends on MODIFY_LDT_SYSCALL
1721 prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1723 Linux can emulate a math coprocessor (used for floating point
1724 operations) if you don't have one. 486DX and Pentium processors have
1725 a math coprocessor built in, 486SX and 386 do not, unless you added
1726 a 487DX or 387, respectively. (The messages during boot time can
1727 give you some hints here ["man dmesg"].) Everyone needs either a
1728 coprocessor or this emulation.
1730 If you don't have a math coprocessor, you need to say Y here; if you
1731 say Y here even though you have a coprocessor, the coprocessor will
1732 be used nevertheless. (This behavior can be changed with the kernel
1733 command line option "no387", which comes handy if your coprocessor
1734 is broken. Try "man bootparam" or see the documentation of your boot
1735 loader (lilo or loadlin) about how to pass options to the kernel at
1736 boot time.) This means that it is a good idea to say Y here if you
1737 intend to use this kernel on different machines.
1739 More information about the internals of the Linux math coprocessor
1740 emulation can be found in <file:arch/x86/math-emu/README>.
1742 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1743 kernel, it won't hurt.
1747 prompt "MTRR (Memory Type Range Register) support" if EXPERT
1749 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1750 the Memory Type Range Registers (MTRRs) may be used to control
1751 processor access to memory ranges. This is most useful if you have
1752 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1753 allows bus write transfers to be combined into a larger transfer
1754 before bursting over the PCI/AGP bus. This can increase performance
1755 of image write operations 2.5 times or more. Saying Y here creates a
1756 /proc/mtrr file which may be used to manipulate your processor's
1757 MTRRs. Typically the X server should use this.
1759 This code has a reasonably generic interface so that similar
1760 control registers on other processors can be easily supported
1763 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1764 Registers (ARRs) which provide a similar functionality to MTRRs. For
1765 these, the ARRs are used to emulate the MTRRs.
1766 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1767 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1768 write-combining. All of these processors are supported by this code
1769 and it makes sense to say Y here if you have one of them.
1771 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1772 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1773 can lead to all sorts of problems, so it's good to say Y here.
1775 You can safely say Y even if your machine doesn't have MTRRs, you'll
1776 just add about 9 KB to your kernel.
1778 See <file:Documentation/x86/mtrr.rst> for more information.
1780 config MTRR_SANITIZER
1782 prompt "MTRR cleanup support"
1785 Convert MTRR layout from continuous to discrete, so X drivers can
1786 add writeback entries.
1788 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1789 The largest mtrr entry size for a continuous block can be set with
1794 config MTRR_SANITIZER_ENABLE_DEFAULT
1795 int "MTRR cleanup enable value (0-1)"
1798 depends on MTRR_SANITIZER
1800 Enable mtrr cleanup default value
1802 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1803 int "MTRR cleanup spare reg num (0-7)"
1806 depends on MTRR_SANITIZER
1808 mtrr cleanup spare entries default, it can be changed via
1809 mtrr_spare_reg_nr=N on the kernel command line.
1813 prompt "x86 PAT support" if EXPERT
1816 Use PAT attributes to setup page level cache control.
1818 PATs are the modern equivalents of MTRRs and are much more
1819 flexible than MTRRs.
1821 Say N here if you see bootup problems (boot crash, boot hang,
1822 spontaneous reboots) or a non-working video driver.
1826 config ARCH_USES_PG_UNCACHED
1832 prompt "x86 architectural random number generator" if EXPERT
1834 Enable the x86 architectural RDRAND instruction
1835 (Intel Bull Mountain technology) to generate random numbers.
1836 If supported, this is a high bandwidth, cryptographically
1837 secure hardware random number generator.
1841 prompt "Supervisor Mode Access Prevention" if EXPERT
1843 Supervisor Mode Access Prevention (SMAP) is a security
1844 feature in newer Intel processors. There is a small
1845 performance cost if this enabled and turned on; there is
1846 also a small increase in the kernel size if this is enabled.
1852 prompt "User Mode Instruction Prevention" if EXPERT
1854 User Mode Instruction Prevention (UMIP) is a security feature in
1855 some x86 processors. If enabled, a general protection fault is
1856 issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1857 executed in user mode. These instructions unnecessarily expose
1858 information about the hardware state.
1860 The vast majority of applications do not use these instructions.
1861 For the very few that do, software emulation is provided in
1862 specific cases in protected and virtual-8086 modes. Emulated
1865 config X86_INTEL_MEMORY_PROTECTION_KEYS
1866 prompt "Memory Protection Keys"
1868 # Note: only available in 64-bit mode
1869 depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1870 select ARCH_USES_HIGH_VMA_FLAGS
1871 select ARCH_HAS_PKEYS
1873 Memory Protection Keys provides a mechanism for enforcing
1874 page-based protections, but without requiring modification of the
1875 page tables when an application changes protection domains.
1877 For details, see Documentation/core-api/protection-keys.rst
1882 prompt "TSX enable mode"
1883 depends on CPU_SUP_INTEL
1884 default X86_INTEL_TSX_MODE_OFF
1886 Intel's TSX (Transactional Synchronization Extensions) feature
1887 allows to optimize locking protocols through lock elision which
1888 can lead to a noticeable performance boost.
1890 On the other hand it has been shown that TSX can be exploited
1891 to form side channel attacks (e.g. TAA) and chances are there
1892 will be more of those attacks discovered in the future.
1894 Therefore TSX is not enabled by default (aka tsx=off). An admin
1895 might override this decision by tsx=on the command line parameter.
1896 Even with TSX enabled, the kernel will attempt to enable the best
1897 possible TAA mitigation setting depending on the microcode available
1898 for the particular machine.
1900 This option allows to set the default tsx mode between tsx=on, =off
1901 and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1904 Say off if not sure, auto if TSX is in use but it should be used on safe
1905 platforms or on if TSX is in use and the security aspect of tsx is not
1908 config X86_INTEL_TSX_MODE_OFF
1911 TSX is disabled if possible - equals to tsx=off command line parameter.
1913 config X86_INTEL_TSX_MODE_ON
1916 TSX is always enabled on TSX capable HW - equals the tsx=on command
1919 config X86_INTEL_TSX_MODE_AUTO
1922 TSX is enabled on TSX capable HW that is believed to be safe against
1923 side channel attacks- equals the tsx=auto command line parameter.
1927 bool "EFI runtime service support"
1930 select EFI_RUNTIME_WRAPPERS
1931 select ARCH_USE_MEMREMAP_PROT
1933 This enables the kernel to use EFI runtime services that are
1934 available (such as the EFI variable services).
1936 This option is only useful on systems that have EFI firmware.
1937 In addition, you should use the latest ELILO loader available
1938 at <http://elilo.sourceforge.net> in order to take advantage
1939 of EFI runtime services. However, even with this option, the
1940 resultant kernel should continue to boot on existing non-EFI
1944 bool "EFI stub support"
1945 depends on EFI && !X86_USE_3DNOW
1948 This kernel feature allows a bzImage to be loaded directly
1949 by EFI firmware without the use of a bootloader.
1951 See Documentation/admin-guide/efi-stub.rst for more information.
1954 bool "EFI mixed-mode support"
1955 depends on EFI_STUB && X86_64
1957 Enabling this feature allows a 64-bit kernel to be booted
1958 on a 32-bit firmware, provided that your CPU supports 64-bit
1961 Note that it is not possible to boot a mixed-mode enabled
1962 kernel via the EFI boot stub - a bootloader that supports
1963 the EFI handover protocol must be used.
1967 source "kernel/Kconfig.hz"
1970 bool "kexec system call"
1973 kexec is a system call that implements the ability to shutdown your
1974 current kernel, and to start another kernel. It is like a reboot
1975 but it is independent of the system firmware. And like a reboot
1976 you can start any kernel with it, not just Linux.
1978 The name comes from the similarity to the exec system call.
1980 It is an ongoing process to be certain the hardware in a machine
1981 is properly shutdown, so do not be surprised if this code does not
1982 initially work for you. As of this writing the exact hardware
1983 interface is strongly in flux, so no good recommendation can be
1987 bool "kexec file based system call"
1992 depends on CRYPTO_SHA256=y
1994 This is new version of kexec system call. This system call is
1995 file based and takes file descriptors as system call argument
1996 for kernel and initramfs as opposed to list of segments as
1997 accepted by previous system call.
1999 config ARCH_HAS_KEXEC_PURGATORY
2003 bool "Verify kernel signature during kexec_file_load() syscall"
2004 depends on KEXEC_FILE
2007 This option makes the kexec_file_load() syscall check for a valid
2008 signature of the kernel image. The image can still be loaded without
2009 a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2010 there's a signature that we can check, then it must be valid.
2012 In addition to this option, you need to enable signature
2013 verification for the corresponding kernel image type being
2014 loaded in order for this to work.
2016 config KEXEC_SIG_FORCE
2017 bool "Require a valid signature in kexec_file_load() syscall"
2018 depends on KEXEC_SIG
2020 This option makes kernel signature verification mandatory for
2021 the kexec_file_load() syscall.
2023 config KEXEC_BZIMAGE_VERIFY_SIG
2024 bool "Enable bzImage signature verification support"
2025 depends on KEXEC_SIG
2026 depends on SIGNED_PE_FILE_VERIFICATION
2027 select SYSTEM_TRUSTED_KEYRING
2029 Enable bzImage signature verification support.
2032 bool "kernel crash dumps"
2033 depends on X86_64 || (X86_32 && HIGHMEM)
2035 Generate crash dump after being started by kexec.
2036 This should be normally only set in special crash dump kernels
2037 which are loaded in the main kernel with kexec-tools into
2038 a specially reserved region and then later executed after
2039 a crash by kdump/kexec. The crash dump kernel must be compiled
2040 to a memory address not used by the main kernel or BIOS using
2041 PHYSICAL_START, or it must be built as a relocatable image
2042 (CONFIG_RELOCATABLE=y).
2043 For more details see Documentation/admin-guide/kdump/kdump.rst
2047 depends on KEXEC && HIBERNATION
2049 Jump between original kernel and kexeced kernel and invoke
2050 code in physical address mode via KEXEC
2052 config PHYSICAL_START
2053 hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2056 This gives the physical address where the kernel is loaded.
2058 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2059 bzImage will decompress itself to above physical address and
2060 run from there. Otherwise, bzImage will run from the address where
2061 it has been loaded by the boot loader and will ignore above physical
2064 In normal kdump cases one does not have to set/change this option
2065 as now bzImage can be compiled as a completely relocatable image
2066 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2067 address. This option is mainly useful for the folks who don't want
2068 to use a bzImage for capturing the crash dump and want to use a
2069 vmlinux instead. vmlinux is not relocatable hence a kernel needs
2070 to be specifically compiled to run from a specific memory area
2071 (normally a reserved region) and this option comes handy.
2073 So if you are using bzImage for capturing the crash dump,
2074 leave the value here unchanged to 0x1000000 and set
2075 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
2076 for capturing the crash dump change this value to start of
2077 the reserved region. In other words, it can be set based on
2078 the "X" value as specified in the "crashkernel=YM@XM"
2079 command line boot parameter passed to the panic-ed
2080 kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2081 for more details about crash dumps.
2083 Usage of bzImage for capturing the crash dump is recommended as
2084 one does not have to build two kernels. Same kernel can be used
2085 as production kernel and capture kernel. Above option should have
2086 gone away after relocatable bzImage support is introduced. But it
2087 is present because there are users out there who continue to use
2088 vmlinux for dump capture. This option should go away down the
2091 Don't change this unless you know what you are doing.
2094 bool "Build a relocatable kernel"
2097 This builds a kernel image that retains relocation information
2098 so it can be loaded someplace besides the default 1MB.
2099 The relocations tend to make the kernel binary about 10% larger,
2100 but are discarded at runtime.
2102 One use is for the kexec on panic case where the recovery kernel
2103 must live at a different physical address than the primary
2106 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2107 it has been loaded at and the compile time physical address
2108 (CONFIG_PHYSICAL_START) is used as the minimum location.
2110 config RANDOMIZE_BASE
2111 bool "Randomize the address of the kernel image (KASLR)"
2112 depends on RELOCATABLE
2115 In support of Kernel Address Space Layout Randomization (KASLR),
2116 this randomizes the physical address at which the kernel image
2117 is decompressed and the virtual address where the kernel
2118 image is mapped, as a security feature that deters exploit
2119 attempts relying on knowledge of the location of kernel
2122 On 64-bit, the kernel physical and virtual addresses are
2123 randomized separately. The physical address will be anywhere
2124 between 16MB and the top of physical memory (up to 64TB). The
2125 virtual address will be randomized from 16MB up to 1GB (9 bits
2126 of entropy). Note that this also reduces the memory space
2127 available to kernel modules from 1.5GB to 1GB.
2129 On 32-bit, the kernel physical and virtual addresses are
2130 randomized together. They will be randomized from 16MB up to
2131 512MB (8 bits of entropy).
2133 Entropy is generated using the RDRAND instruction if it is
2134 supported. If RDTSC is supported, its value is mixed into
2135 the entropy pool as well. If neither RDRAND nor RDTSC are
2136 supported, then entropy is read from the i8254 timer. The
2137 usable entropy is limited by the kernel being built using
2138 2GB addressing, and that PHYSICAL_ALIGN must be at a
2139 minimum of 2MB. As a result, only 10 bits of entropy are
2140 theoretically possible, but the implementations are further
2141 limited due to memory layouts.
2145 # Relocation on x86 needs some additional build support
2146 config X86_NEED_RELOCS
2148 depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2150 config PHYSICAL_ALIGN
2151 hex "Alignment value to which kernel should be aligned"
2153 range 0x2000 0x1000000 if X86_32
2154 range 0x200000 0x1000000 if X86_64
2156 This value puts the alignment restrictions on physical address
2157 where kernel is loaded and run from. Kernel is compiled for an
2158 address which meets above alignment restriction.
2160 If bootloader loads the kernel at a non-aligned address and
2161 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2162 address aligned to above value and run from there.
2164 If bootloader loads the kernel at a non-aligned address and
2165 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2166 load address and decompress itself to the address it has been
2167 compiled for and run from there. The address for which kernel is
2168 compiled already meets above alignment restrictions. Hence the
2169 end result is that kernel runs from a physical address meeting
2170 above alignment restrictions.
2172 On 32-bit this value must be a multiple of 0x2000. On 64-bit
2173 this value must be a multiple of 0x200000.
2175 Don't change this unless you know what you are doing.
2177 config DYNAMIC_MEMORY_LAYOUT
2180 This option makes base addresses of vmalloc and vmemmap as well as
2181 __PAGE_OFFSET movable during boot.
2183 config RANDOMIZE_MEMORY
2184 bool "Randomize the kernel memory sections"
2186 depends on RANDOMIZE_BASE
2187 select DYNAMIC_MEMORY_LAYOUT
2188 default RANDOMIZE_BASE
2190 Randomizes the base virtual address of kernel memory sections
2191 (physical memory mapping, vmalloc & vmemmap). This security feature
2192 makes exploits relying on predictable memory locations less reliable.
2194 The order of allocations remains unchanged. Entropy is generated in
2195 the same way as RANDOMIZE_BASE. Current implementation in the optimal
2196 configuration have in average 30,000 different possible virtual
2197 addresses for each memory section.
2201 config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2202 hex "Physical memory mapping padding" if EXPERT
2203 depends on RANDOMIZE_MEMORY
2204 default "0xa" if MEMORY_HOTPLUG
2206 range 0x1 0x40 if MEMORY_HOTPLUG
2209 Define the padding in terabytes added to the existing physical
2210 memory size during kernel memory randomization. It is useful
2211 for memory hotplug support but reduces the entropy available for
2212 address randomization.
2214 If unsure, leave at the default value.
2220 config BOOTPARAM_HOTPLUG_CPU0
2221 bool "Set default setting of cpu0_hotpluggable"
2222 depends on HOTPLUG_CPU
2224 Set whether default state of cpu0_hotpluggable is on or off.
2226 Say Y here to enable CPU0 hotplug by default. If this switch
2227 is turned on, there is no need to give cpu0_hotplug kernel
2228 parameter and the CPU0 hotplug feature is enabled by default.
2230 Please note: there are two known CPU0 dependencies if you want
2231 to enable the CPU0 hotplug feature either by this switch or by
2232 cpu0_hotplug kernel parameter.
2234 First, resume from hibernate or suspend always starts from CPU0.
2235 So hibernate and suspend are prevented if CPU0 is offline.
2237 Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2238 offline if any interrupt can not migrate out of CPU0. There may
2239 be other CPU0 dependencies.
2241 Please make sure the dependencies are under your control before
2242 you enable this feature.
2244 Say N if you don't want to enable CPU0 hotplug feature by default.
2245 You still can enable the CPU0 hotplug feature at boot by kernel
2246 parameter cpu0_hotplug.
2248 config DEBUG_HOTPLUG_CPU0
2250 prompt "Debug CPU0 hotplug"
2251 depends on HOTPLUG_CPU
2253 Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2254 soon as possible and boots up userspace with CPU0 offlined. User
2255 can online CPU0 back after boot time.
2257 To debug CPU0 hotplug, you need to enable CPU0 offline/online
2258 feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2259 compilation or giving cpu0_hotplug kernel parameter at boot.
2265 prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2266 depends on COMPAT_32
2268 Certain buggy versions of glibc will crash if they are
2269 presented with a 32-bit vDSO that is not mapped at the address
2270 indicated in its segment table.
2272 The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2273 and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2274 49ad572a70b8aeb91e57483a11dd1b77e31c4468. Glibc 2.3.3 is
2275 the only released version with the bug, but OpenSUSE 9
2276 contains a buggy "glibc 2.3.2".
2278 The symptom of the bug is that everything crashes on startup, saying:
2279 dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2281 Saying Y here changes the default value of the vdso32 boot
2282 option from 1 to 0, which turns off the 32-bit vDSO entirely.
2283 This works around the glibc bug but hurts performance.
2285 If unsure, say N: if you are compiling your own kernel, you
2286 are unlikely to be using a buggy version of glibc.
2289 prompt "vsyscall table for legacy applications"
2291 default LEGACY_VSYSCALL_XONLY
2293 Legacy user code that does not know how to find the vDSO expects
2294 to be able to issue three syscalls by calling fixed addresses in
2295 kernel space. Since this location is not randomized with ASLR,
2296 it can be used to assist security vulnerability exploitation.
2298 This setting can be changed at boot time via the kernel command
2299 line parameter vsyscall=[emulate|xonly|none].
2301 On a system with recent enough glibc (2.14 or newer) and no
2302 static binaries, you can say None without a performance penalty
2303 to improve security.
2305 If unsure, select "Emulate execution only".
2307 config LEGACY_VSYSCALL_EMULATE
2308 bool "Full emulation"
2310 The kernel traps and emulates calls into the fixed vsyscall
2311 address mapping. This makes the mapping non-executable, but
2312 it still contains readable known contents, which could be
2313 used in certain rare security vulnerability exploits. This
2314 configuration is recommended when using legacy userspace
2315 that still uses vsyscalls along with legacy binary
2316 instrumentation tools that require code to be readable.
2318 An example of this type of legacy userspace is running
2319 Pin on an old binary that still uses vsyscalls.
2321 config LEGACY_VSYSCALL_XONLY
2322 bool "Emulate execution only"
2324 The kernel traps and emulates calls into the fixed vsyscall
2325 address mapping and does not allow reads. This
2326 configuration is recommended when userspace might use the
2327 legacy vsyscall area but support for legacy binary
2328 instrumentation of legacy code is not needed. It mitigates
2329 certain uses of the vsyscall area as an ASLR-bypassing
2332 config LEGACY_VSYSCALL_NONE
2335 There will be no vsyscall mapping at all. This will
2336 eliminate any risk of ASLR bypass due to the vsyscall
2337 fixed address mapping. Attempts to use the vsyscalls
2338 will be reported to dmesg, so that either old or
2339 malicious userspace programs can be identified.
2344 bool "Built-in kernel command line"
2346 Allow for specifying boot arguments to the kernel at
2347 build time. On some systems (e.g. embedded ones), it is
2348 necessary or convenient to provide some or all of the
2349 kernel boot arguments with the kernel itself (that is,
2350 to not rely on the boot loader to provide them.)
2352 To compile command line arguments into the kernel,
2353 set this option to 'Y', then fill in the
2354 boot arguments in CONFIG_CMDLINE.
2356 Systems with fully functional boot loaders (i.e. non-embedded)
2357 should leave this option set to 'N'.
2360 string "Built-in kernel command string"
2361 depends on CMDLINE_BOOL
2364 Enter arguments here that should be compiled into the kernel
2365 image and used at boot time. If the boot loader provides a
2366 command line at boot time, it is appended to this string to
2367 form the full kernel command line, when the system boots.
2369 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2370 change this behavior.
2372 In most cases, the command line (whether built-in or provided
2373 by the boot loader) should specify the device for the root
2376 config CMDLINE_OVERRIDE
2377 bool "Built-in command line overrides boot loader arguments"
2378 depends on CMDLINE_BOOL && CMDLINE != ""
2380 Set this option to 'Y' to have the kernel ignore the boot loader
2381 command line, and use ONLY the built-in command line.
2383 This is used to work around broken boot loaders. This should
2384 be set to 'N' under normal conditions.
2386 config MODIFY_LDT_SYSCALL
2387 bool "Enable the LDT (local descriptor table)" if EXPERT
2390 Linux can allow user programs to install a per-process x86
2391 Local Descriptor Table (LDT) using the modify_ldt(2) system
2392 call. This is required to run 16-bit or segmented code such as
2393 DOSEMU or some Wine programs. It is also used by some very old
2394 threading libraries.
2396 Enabling this feature adds a small amount of overhead to
2397 context switches and increases the low-level kernel attack
2398 surface. Disabling it removes the modify_ldt(2) system call.
2400 Saying 'N' here may make sense for embedded or server kernels.
2402 source "kernel/livepatch/Kconfig"
2407 def_bool $(cc-option,-mharden-sls=all)
2409 config CC_HAS_RETURN_THUNK
2410 def_bool $(cc-option,-mfunction-return=thunk-extern)
2412 menuconfig CPU_MITIGATIONS
2413 bool "Mitigations for CPU vulnerabilities"
2416 Say Y here to enable options which enable mitigations for hardware
2417 vulnerabilities (usually related to speculative execution).
2419 If you say N, all mitigations will be disabled. You really
2420 should know what you are doing to say so.
2424 config PAGE_TABLE_ISOLATION
2425 bool "Remove the kernel mapping in user mode"
2427 depends on (X86_64 || X86_PAE)
2429 This feature reduces the number of hardware side channels by
2430 ensuring that the majority of kernel addresses are not mapped
2433 See Documentation/x86/pti.rst for more details.
2436 bool "Avoid speculative indirect branches in kernel"
2439 Compile kernel with the retpoline compiler options to guard against
2440 kernel-to-user data leaks by avoiding speculative indirect
2441 branches. Requires a compiler with -mindirect-branch=thunk-extern
2442 support for full protection. The kernel may run slower.
2445 bool "Enable return-thunks"
2446 depends on RETPOLINE && CC_HAS_RETURN_THUNK
2449 Compile the kernel with the return-thunks compiler option to guard
2450 against kernel-to-user data leaks by avoiding return speculation.
2451 Requires a compiler with -mfunction-return=thunk-extern
2452 support for full protection. The kernel may run slower.
2454 config CPU_UNRET_ENTRY
2455 bool "Enable UNRET on kernel entry"
2456 depends on CPU_SUP_AMD && RETHUNK && X86_64
2459 Compile the kernel with support for the retbleed=unret mitigation.
2461 config CPU_IBPB_ENTRY
2462 bool "Enable IBPB on kernel entry"
2463 depends on CPU_SUP_AMD && X86_64
2466 Compile the kernel with support for the retbleed=ibpb mitigation.
2468 config CPU_IBRS_ENTRY
2469 bool "Enable IBRS on kernel entry"
2470 depends on CPU_SUP_INTEL && X86_64
2473 Compile the kernel with support for the spectre_v2=ibrs mitigation.
2474 This mitigates both spectre_v2 and retbleed at great cost to
2478 bool "Mitigate speculative RAS overflow on AMD"
2479 depends on CPU_SUP_AMD && X86_64 && RETHUNK
2482 Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2485 bool "Mitigate Straight-Line-Speculation"
2486 depends on CC_HAS_SLS && X86_64
2489 Compile the kernel with straight-line-speculation options to guard
2490 against straight line speculation. The kernel image might be slightly
2493 config GDS_FORCE_MITIGATION
2494 bool "Force GDS Mitigation"
2495 depends on CPU_SUP_INTEL
2498 Gather Data Sampling (GDS) is a hardware vulnerability which allows
2499 unprivileged speculative access to data which was previously stored in
2502 This option is equivalent to setting gather_data_sampling=force on the
2503 command line. The microcode mitigation is used if present, otherwise
2504 AVX is disabled as a mitigation. On affected systems that are missing
2505 the microcode any userspace code that unconditionally uses AVX will
2506 break with this option set.
2508 Setting this option on systems not vulnerable to GDS has no effect.
2512 config MITIGATION_RFDS
2513 bool "RFDS Mitigation"
2514 depends on CPU_SUP_INTEL
2517 Enable mitigation for Register File Data Sampling (RFDS) by default.
2518 RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2519 allows unprivileged speculative access to stale data previously
2520 stored in floating point, vector and integer registers.
2521 See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2525 config ARCH_HAS_ADD_PAGES
2527 depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2529 config ARCH_ENABLE_MEMORY_HOTPLUG
2531 depends on X86_64 || (X86_32 && HIGHMEM)
2533 config ARCH_ENABLE_MEMORY_HOTREMOVE
2535 depends on MEMORY_HOTPLUG
2537 config USE_PERCPU_NUMA_NODE_ID
2541 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2543 depends on X86_64 || X86_PAE
2545 config ARCH_ENABLE_HUGEPAGE_MIGRATION
2547 depends on X86_64 && HUGETLB_PAGE && MIGRATION
2549 config ARCH_ENABLE_THP_MIGRATION
2551 depends on X86_64 && TRANSPARENT_HUGEPAGE
2553 menu "Power management and ACPI options"
2555 config ARCH_HIBERNATION_HEADER
2557 depends on HIBERNATION
2559 source "kernel/power/Kconfig"
2561 source "drivers/acpi/Kconfig"
2563 source "drivers/sfi/Kconfig"
2570 tristate "APM (Advanced Power Management) BIOS support"
2571 depends on X86_32 && PM_SLEEP
2573 APM is a BIOS specification for saving power using several different
2574 techniques. This is mostly useful for battery powered laptops with
2575 APM compliant BIOSes. If you say Y here, the system time will be
2576 reset after a RESUME operation, the /proc/apm device will provide
2577 battery status information, and user-space programs will receive
2578 notification of APM "events" (e.g. battery status change).
2580 If you select "Y" here, you can disable actual use of the APM
2581 BIOS by passing the "apm=off" option to the kernel at boot time.
2583 Note that the APM support is almost completely disabled for
2584 machines with more than one CPU.
2586 In order to use APM, you will need supporting software. For location
2587 and more information, read <file:Documentation/power/apm-acpi.rst>
2588 and the Battery Powered Linux mini-HOWTO, available from
2589 <http://www.tldp.org/docs.html#howto>.
2591 This driver does not spin down disk drives (see the hdparm(8)
2592 manpage ("man 8 hdparm") for that), and it doesn't turn off
2593 VESA-compliant "green" monitors.
2595 This driver does not support the TI 4000M TravelMate and the ACER
2596 486/DX4/75 because they don't have compliant BIOSes. Many "green"
2597 desktop machines also don't have compliant BIOSes, and this driver
2598 may cause those machines to panic during the boot phase.
2600 Generally, if you don't have a battery in your machine, there isn't
2601 much point in using this driver and you should say N. If you get
2602 random kernel OOPSes or reboots that don't seem to be related to
2603 anything, try disabling/enabling this option (or disabling/enabling
2606 Some other things you should try when experiencing seemingly random,
2609 1) make sure that you have enough swap space and that it is
2611 2) pass the "no-hlt" option to the kernel
2612 3) switch on floating point emulation in the kernel and pass
2613 the "no387" option to the kernel
2614 4) pass the "floppy=nodma" option to the kernel
2615 5) pass the "mem=4M" option to the kernel (thereby disabling
2616 all but the first 4 MB of RAM)
2617 6) make sure that the CPU is not over clocked.
2618 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2619 8) disable the cache from your BIOS settings
2620 9) install a fan for the video card or exchange video RAM
2621 10) install a better fan for the CPU
2622 11) exchange RAM chips
2623 12) exchange the motherboard.
2625 To compile this driver as a module, choose M here: the
2626 module will be called apm.
2630 config APM_IGNORE_USER_SUSPEND
2631 bool "Ignore USER SUSPEND"
2633 This option will ignore USER SUSPEND requests. On machines with a
2634 compliant APM BIOS, you want to say N. However, on the NEC Versa M
2635 series notebooks, it is necessary to say Y because of a BIOS bug.
2637 config APM_DO_ENABLE
2638 bool "Enable PM at boot time"
2640 Enable APM features at boot time. From page 36 of the APM BIOS
2641 specification: "When disabled, the APM BIOS does not automatically
2642 power manage devices, enter the Standby State, enter the Suspend
2643 State, or take power saving steps in response to CPU Idle calls."
2644 This driver will make CPU Idle calls when Linux is idle (unless this
2645 feature is turned off -- see "Do CPU IDLE calls", below). This
2646 should always save battery power, but more complicated APM features
2647 will be dependent on your BIOS implementation. You may need to turn
2648 this option off if your computer hangs at boot time when using APM
2649 support, or if it beeps continuously instead of suspending. Turn
2650 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2651 T400CDT. This is off by default since most machines do fine without
2656 bool "Make CPU Idle calls when idle"
2658 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2659 On some machines, this can activate improved power savings, such as
2660 a slowed CPU clock rate, when the machine is idle. These idle calls
2661 are made after the idle loop has run for some length of time (e.g.,
2662 333 mS). On some machines, this will cause a hang at boot time or
2663 whenever the CPU becomes idle. (On machines with more than one CPU,
2664 this option does nothing.)
2666 config APM_DISPLAY_BLANK
2667 bool "Enable console blanking using APM"
2669 Enable console blanking using the APM. Some laptops can use this to
2670 turn off the LCD backlight when the screen blanker of the Linux
2671 virtual console blanks the screen. Note that this is only used by
2672 the virtual console screen blanker, and won't turn off the backlight
2673 when using the X Window system. This also doesn't have anything to
2674 do with your VESA-compliant power-saving monitor. Further, this
2675 option doesn't work for all laptops -- it might not turn off your
2676 backlight at all, or it might print a lot of errors to the console,
2677 especially if you are using gpm.
2679 config APM_ALLOW_INTS
2680 bool "Allow interrupts during APM BIOS calls"
2682 Normally we disable external interrupts while we are making calls to
2683 the APM BIOS as a measure to lessen the effects of a badly behaving
2684 BIOS implementation. The BIOS should reenable interrupts if it
2685 needs to. Unfortunately, some BIOSes do not -- especially those in
2686 many of the newer IBM Thinkpads. If you experience hangs when you
2687 suspend, try setting this to Y. Otherwise, say N.
2691 source "drivers/cpufreq/Kconfig"
2693 source "drivers/cpuidle/Kconfig"
2695 source "drivers/idle/Kconfig"
2700 menu "Bus options (PCI etc.)"
2703 prompt "PCI access mode"
2704 depends on X86_32 && PCI
2707 On PCI systems, the BIOS can be used to detect the PCI devices and
2708 determine their configuration. However, some old PCI motherboards
2709 have BIOS bugs and may crash if this is done. Also, some embedded
2710 PCI-based systems don't have any BIOS at all. Linux can also try to
2711 detect the PCI hardware directly without using the BIOS.
2713 With this option, you can specify how Linux should detect the
2714 PCI devices. If you choose "BIOS", the BIOS will be used,
2715 if you choose "Direct", the BIOS won't be used, and if you
2716 choose "MMConfig", then PCI Express MMCONFIG will be used.
2717 If you choose "Any", the kernel will try MMCONFIG, then the
2718 direct access method and falls back to the BIOS if that doesn't
2719 work. If unsure, go with the default, which is "Any".
2724 config PCI_GOMMCONFIG
2741 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2743 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2746 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2749 bool "Support mmconfig PCI config space access" if X86_64
2751 depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2752 depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2756 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2760 depends on PCI && XEN
2763 config MMCONF_FAM10H
2765 depends on X86_64 && PCI_MMCONFIG && ACPI
2767 config PCI_CNB20LE_QUIRK
2768 bool "Read CNB20LE Host Bridge Windows" if EXPERT
2771 Read the PCI windows out of the CNB20LE host bridge. This allows
2772 PCI hotplug to work on systems with the CNB20LE chipset which do
2775 There's no public spec for this chipset, and this functionality
2776 is known to be incomplete.
2778 You should say N unless you know you need this.
2781 bool "ISA bus support on modern systems" if EXPERT
2783 Expose ISA bus device drivers and options available for selection and
2784 configuration. Enable this option if your target machine has an ISA
2785 bus. ISA is an older system, displaced by PCI and newer bus
2786 architectures -- if your target machine is modern, it probably does
2787 not have an ISA bus.
2791 # x86_64 have no ISA slots, but can have ISA-style DMA.
2793 bool "ISA-style DMA support" if (X86_64 && EXPERT)
2796 Enables ISA-style DMA support for devices requiring such controllers.
2804 Find out whether you have ISA slots on your motherboard. ISA is the
2805 name of a bus system, i.e. the way the CPU talks to the other stuff
2806 inside your box. Other bus systems are PCI, EISA, MicroChannel
2807 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
2808 newer boards don't support it. If you have ISA, say Y, otherwise N.
2811 tristate "NatSemi SCx200 support"
2813 This provides basic support for National Semiconductor's
2814 (now AMD's) Geode processors. The driver probes for the
2815 PCI-IDs of several on-chip devices, so its a good dependency
2816 for other scx200_* drivers.
2818 If compiled as a module, the driver is named scx200.
2820 config SCx200HR_TIMER
2821 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2825 This driver provides a clocksource built upon the on-chip
2826 27MHz high-resolution timer. Its also a workaround for
2827 NSC Geode SC-1100's buggy TSC, which loses time when the
2828 processor goes idle (as is done by the scheduler). The
2829 other workaround is idle=poll boot option.
2832 bool "One Laptop Per Child support"
2840 Add support for detecting the unique features of the OLPC
2844 bool "OLPC XO-1 Power Management"
2845 depends on OLPC && MFD_CS5535=y && PM_SLEEP
2847 Add support for poweroff and suspend of the OLPC XO-1 laptop.
2850 bool "OLPC XO-1 Real Time Clock"
2851 depends on OLPC_XO1_PM && RTC_DRV_CMOS
2853 Add support for the XO-1 real time clock, which can be used as a
2854 programmable wakeup source.
2857 bool "OLPC XO-1 SCI extras"
2858 depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2862 Add support for SCI-based features of the OLPC XO-1 laptop:
2863 - EC-driven system wakeups
2867 - AC adapter status updates
2868 - Battery status updates
2870 config OLPC_XO15_SCI
2871 bool "OLPC XO-1.5 SCI extras"
2872 depends on OLPC && ACPI
2875 Add support for SCI-based features of the OLPC XO-1.5 laptop:
2876 - EC-driven system wakeups
2877 - AC adapter status updates
2878 - Battery status updates
2881 bool "PCEngines ALIX System Support (LED setup)"
2884 This option enables system support for the PCEngines ALIX.
2885 At present this just sets up LEDs for GPIO control on
2886 ALIX2/3/6 boards. However, other system specific setup should
2889 Note: You must still enable the drivers for GPIO and LED support
2890 (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2892 Note: You have to set alix.force=1 for boards with Award BIOS.
2895 bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2898 This option enables system support for the Soekris Engineering net5501.
2901 bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2905 This option enables system support for the Traverse Technologies GEOS.
2908 bool "Technologic Systems TS-5500 platform support"
2910 select CHECK_SIGNATURE
2914 This option enables system support for the Technologic Systems TS-5500.
2920 depends on CPU_SUP_AMD && PCI
2923 bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2925 Firmwares often provide initial graphics framebuffers so the BIOS,
2926 bootloader or kernel can show basic video-output during boot for
2927 user-guidance and debugging. Historically, x86 used the VESA BIOS
2928 Extensions and EFI-framebuffers for this, which are mostly limited
2930 This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2931 framebuffers so the new generic system-framebuffer drivers can be
2932 used on x86. If the framebuffer is not compatible with the generic
2933 modes, it is advertised as fallback platform framebuffer so legacy
2934 drivers like efifb, vesafb and uvesafb can pick it up.
2935 If this option is not selected, all system framebuffers are always
2936 marked as fallback platform framebuffers as usual.
2938 Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2939 not be able to pick up generic system framebuffers if this option
2940 is selected. You are highly encouraged to enable simplefb as
2941 replacement if you select this option. simplefb can correctly deal
2942 with generic system framebuffers. But you should still keep vesafb
2943 and others enabled as fallback if a system framebuffer is
2944 incompatible with simplefb.
2951 menu "Binary Emulations"
2953 config IA32_EMULATION
2954 bool "IA32 Emulation"
2956 select ARCH_WANT_OLD_COMPAT_IPC
2958 select COMPAT_BINFMT_ELF
2959 select COMPAT_OLD_SIGACTION
2961 Include code to run legacy 32-bit programs under a
2962 64-bit kernel. You should likely turn this on, unless you're
2963 100% sure that you don't have any 32-bit programs left.
2966 tristate "IA32 a.out support"
2967 depends on IA32_EMULATION
2970 Support old a.out binaries in the 32bit emulation.
2973 bool "x32 ABI for 64-bit mode"
2975 # llvm-objcopy does not convert x86_64 .note.gnu.property or
2976 # compressed debug sections to x86_x32 properly:
2977 # https://github.com/ClangBuiltLinux/linux/issues/514
2978 # https://github.com/ClangBuiltLinux/linux/issues/1141
2979 depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
2981 Include code to run binaries for the x32 native 32-bit ABI
2982 for 64-bit processors. An x32 process gets access to the
2983 full 64-bit register file and wide data path while leaving
2984 pointers at 32 bits for smaller memory footprint.
2986 You will need a recent binutils (2.22 or later) with
2987 elf32_x86_64 support enabled to compile a kernel with this
2992 depends on IA32_EMULATION || X86_32
2994 select OLD_SIGSUSPEND3
2998 depends on IA32_EMULATION || X86_X32
3001 config COMPAT_FOR_U64_ALIGNMENT
3004 config SYSVIPC_COMPAT
3012 config HAVE_ATOMIC_IOMAP
3016 source "drivers/firmware/Kconfig"
3018 source "arch/x86/kvm/Kconfig"
3020 source "arch/x86/Kconfig.assembler"