1 /* SPDX-License-Identifier: GPL-2.0 */
3 * Asm versions of Xen pv-ops, suitable for direct use.
5 * We only bother with direct forms (ie, vcpu in percpu data) of the
6 * operations here; the indirect forms are better handled in C.
10 #include <asm/asm-offsets.h>
11 #include <asm/percpu.h>
12 #include <asm/processor-flags.h>
13 #include <asm/segment.h>
14 #include <asm/thread_info.h>
16 #include <asm/frame.h>
17 #include <asm/unwind_hints.h>
19 #include <xen/interface/xen.h>
21 #include <linux/init.h>
22 #include <linux/linkage.h>
23 #include <../entry/calling.h>
26 * Enable events. This clears the event mask and tests the pending
27 * event status with one and operation. If there are pending events,
28 * then enter the hypervisor to get them handled.
30 SYM_FUNC_START(xen_irq_enable_direct)
33 movb $0, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
36 * Preempt here doesn't matter because that will deal with any
37 * pending interrupts. The pending check may end up being run
38 * on the wrong CPU, but that doesn't hurt.
41 /* Test for pending */
42 testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_pending
49 SYM_FUNC_END(xen_irq_enable_direct)
53 * Disabling events is simply a matter of making the event mask
56 SYM_FUNC_START(xen_irq_disable_direct)
57 movb $1, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
59 SYM_FUNC_END(xen_irq_disable_direct)
62 * (xen_)save_fl is used to get the current interrupt enable status.
63 * Callers expect the status to be in X86_EFLAGS_IF, and other bits
64 * may be set in the return value. We take advantage of this by
65 * making sure that X86_EFLAGS_IF has the right value (and other bits
66 * in that byte are 0), but other bits in the return value are
67 * undefined. We need to toggle the state of the bit, because Xen and
68 * x86 use opposite senses (mask vs enable).
70 SYM_FUNC_START(xen_save_fl_direct)
71 testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
75 SYM_FUNC_END(xen_save_fl_direct)
78 * Force an event check by making a hypercall, but preserve regs
79 * before making the call.
81 SYM_FUNC_START(check_events)
92 call xen_force_evtchn_callback
104 SYM_FUNC_END(check_events)
106 SYM_FUNC_START(xen_read_cr2)
108 _ASM_MOV PER_CPU_VAR(xen_vcpu), %_ASM_AX
109 _ASM_MOV XEN_vcpu_info_arch_cr2(%_ASM_AX), %_ASM_AX
112 SYM_FUNC_END(xen_read_cr2);
114 SYM_FUNC_START(xen_read_cr2_direct)
116 _ASM_MOV PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_arch_cr2, %_ASM_AX
119 SYM_FUNC_END(xen_read_cr2_direct);
121 .macro xen_pv_trap name
122 SYM_CODE_START(xen_\name)
127 SYM_CODE_END(xen_\name)
128 _ASM_NOKPROBE(xen_\name)
131 xen_pv_trap asm_exc_divide_error
132 xen_pv_trap asm_xenpv_exc_debug
133 xen_pv_trap asm_exc_int3
134 xen_pv_trap asm_xenpv_exc_nmi
135 xen_pv_trap asm_exc_overflow
136 xen_pv_trap asm_exc_bounds
137 xen_pv_trap asm_exc_invalid_op
138 xen_pv_trap asm_exc_device_not_available
139 xen_pv_trap asm_xenpv_exc_double_fault
140 xen_pv_trap asm_exc_coproc_segment_overrun
141 xen_pv_trap asm_exc_invalid_tss
142 xen_pv_trap asm_exc_segment_not_present
143 xen_pv_trap asm_exc_stack_segment
144 xen_pv_trap asm_exc_general_protection
145 xen_pv_trap asm_exc_page_fault
146 xen_pv_trap asm_exc_spurious_interrupt_bug
147 xen_pv_trap asm_exc_coprocessor_error
148 xen_pv_trap asm_exc_alignment_check
149 #ifdef CONFIG_X86_MCE
150 xen_pv_trap asm_xenpv_exc_machine_check
151 #endif /* CONFIG_X86_MCE */
152 xen_pv_trap asm_exc_simd_coprocessor_error
153 #ifdef CONFIG_IA32_EMULATION
154 xen_pv_trap entry_INT80_compat
156 xen_pv_trap asm_exc_xen_unknown_trap
157 xen_pv_trap asm_exc_xen_hypervisor_callback
160 SYM_CODE_START(xen_early_idt_handler_array)
162 .rept NUM_EXCEPTION_VECTORS
166 jmp early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE
168 .fill xen_early_idt_handler_array + i*XEN_EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc
170 SYM_CODE_END(xen_early_idt_handler_array)
173 hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32
181 * rip <-- standard iret frame
186 * r11 }<-- pushed by hypercall page
189 SYM_CODE_START(xen_iret)
193 SYM_CODE_END(xen_iret)
196 * XEN pv doesn't use trampoline stack, PER_CPU_VAR(cpu_tss_rw + TSS_sp0) is
197 * also the kernel stack. Reusing swapgs_restore_regs_and_return_to_usermode()
198 * in XEN pv would cause %rsp to move up to the top of the kernel stack and
199 * leave the IRET frame below %rsp, which is dangerous to be corrupted if #NMI
200 * interrupts. And swapgs_restore_regs_and_return_to_usermode() pushing the IRET
201 * frame at the same address is useless.
203 SYM_CODE_START(xenpv_restore_regs_and_return_to_usermode)
207 /* stackleak_erase() can work safely on the kernel stack. */
208 STACKLEAK_ERASE_NOCLOBBER
210 addq $8, %rsp /* skip regs->orig_ax */
212 SYM_CODE_END(xenpv_restore_regs_and_return_to_usermode)
215 * Xen handles syscall callbacks much like ordinary exceptions, which
219 * - an iret-like stack frame on the stack (including rcx and r11):
229 /* Normal 64-bit system call target */
230 SYM_CODE_START(xen_entry_SYSCALL_64)
236 * Neither Xen nor the kernel really knows what the old SS and
237 * CS were. The kernel expects __USER_DS and __USER_CS, so
238 * report those values even though Xen will guess its own values.
240 movq $__USER_DS, 4*8(%rsp)
241 movq $__USER_CS, 1*8(%rsp)
243 jmp entry_SYSCALL_64_after_hwframe
244 SYM_CODE_END(xen_entry_SYSCALL_64)
246 #ifdef CONFIG_IA32_EMULATION
248 /* 32-bit compat syscall target */
249 SYM_CODE_START(xen_entry_SYSCALL_compat)
255 * Neither Xen nor the kernel really knows what the old SS and
256 * CS were. The kernel expects __USER32_DS and __USER32_CS, so
257 * report those values even though Xen will guess its own values.
259 movq $__USER32_DS, 4*8(%rsp)
260 movq $__USER32_CS, 1*8(%rsp)
262 jmp entry_SYSCALL_compat_after_hwframe
263 SYM_CODE_END(xen_entry_SYSCALL_compat)
265 /* 32-bit compat sysenter target */
266 SYM_CODE_START(xen_entry_SYSENTER_compat)
269 * NB: Xen is polite and clears TF from EFLAGS for us. This means
270 * that we don't need to guard against single step exceptions here.
276 * Neither Xen nor the kernel really knows what the old SS and
277 * CS were. The kernel expects __USER32_DS and __USER32_CS, so
278 * report those values even though Xen will guess its own values.
280 movq $__USER32_DS, 4*8(%rsp)
281 movq $__USER32_CS, 1*8(%rsp)
283 jmp entry_SYSENTER_compat_after_hwframe
284 SYM_CODE_END(xen_entry_SYSENTER_compat)
286 #else /* !CONFIG_IA32_EMULATION */
288 SYM_CODE_START(xen_entry_SYSCALL_compat)
289 SYM_CODE_START(xen_entry_SYSENTER_compat)
291 lea 16(%rsp), %rsp /* strip %rcx, %r11 */
295 SYM_CODE_END(xen_entry_SYSENTER_compat)
296 SYM_CODE_END(xen_entry_SYSCALL_compat)
298 #endif /* CONFIG_IA32_EMULATION */