2 * Based on arch/arm/mm/proc.S
4 * Copyright (C) 2001 Deep Blue Solutions Ltd.
5 * Copyright (C) 2012 ARM Ltd.
6 * Author: Catalin Marinas <catalin.marinas@arm.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program. If not, see <http://www.gnu.org/licenses/>.
21 #include <linux/init.h>
22 #include <linux/linkage.h>
23 #include <asm/assembler.h>
24 #include <asm/asm-offsets.h>
25 #include <asm/hwcap.h>
26 #include <asm/pgtable.h>
27 #include <asm/pgtable-hwdef.h>
28 #include <asm/cpufeature.h>
29 #include <asm/alternative.h>
31 #ifdef CONFIG_ARM64_64K_PAGES
32 #define TCR_TG_FLAGS TCR_TG0_64K | TCR_TG1_64K
33 #elif defined(CONFIG_ARM64_16K_PAGES)
34 #define TCR_TG_FLAGS TCR_TG0_16K | TCR_TG1_16K
35 #else /* CONFIG_ARM64_4K_PAGES */
36 #define TCR_TG_FLAGS TCR_TG0_4K | TCR_TG1_4K
39 #ifdef CONFIG_RANDOMIZE_BASE
40 #define TCR_KASLR_FLAGS TCR_NFD1
42 #define TCR_KASLR_FLAGS 0
45 #define TCR_SMP_FLAGS TCR_SHARED
47 /* PTWs cacheable, inner/outer WBWA */
48 #define TCR_CACHE_FLAGS TCR_IRGN_WBWA | TCR_ORGN_WBWA
50 #define MAIR(attr, mt) ((attr) << ((mt) * 8))
55 * Idle the processor (wait for interrupt).
58 dsb sy // WFI may enter a low-power mode
65 * cpu_do_suspend - save CPU registers context
67 * x0: virtual address of context pointer
72 mrs x4, contextidr_el1
80 alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
90 stp x10, x11, [x0, #64]
91 stp x12, x13, [x0, #80]
93 ENDPROC(cpu_do_suspend)
96 * cpu_do_resume - restore CPU register context
98 * x0: Address of context pointer
100 .pushsection ".idmap.text", "awx"
103 ldp x4, x5, [x0, #16]
104 ldp x6, x8, [x0, #32]
105 ldp x9, x10, [x0, #48]
106 ldp x11, x12, [x0, #64]
107 ldp x13, x14, [x0, #80]
110 msr contextidr_el1, x4
113 /* Don't change t0sz here, mask those bits when restoring */
115 bfi x8, x7, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
121 * __cpu_setup() cleared MDSCR_EL1.MDE and friends, before unmasking
122 * debug exceptions. By restoring MDSCR_EL1 here, we may take a debug
123 * exception. Mask them until local_daif_restore() in cpu_suspend()
130 alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
137 * Restore oslsr_el1 by writing oslar_el1
140 ubfx x11, x11, #1, #1
142 reset_pmuserenr_el0 x0 // Disable PMU access from EL0
144 alternative_if ARM64_HAS_RAS_EXTN
145 msr_s SYS_DISR_EL1, xzr
146 alternative_else_nop_endif
150 ENDPROC(cpu_do_resume)
155 * cpu_do_switch_mm(pgd_phys, tsk)
157 * Set the translation table base pointer to be pgd_phys.
159 * - pgd_phys - physical address of new TTB
161 ENTRY(cpu_do_switch_mm)
163 mmid x1, x1 // get mm->context.id
165 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
166 bfi x3, x1, #48, #16 // set the ASID field in TTBR0
168 bfi x2, x1, #48, #16 // set the ASID
169 msr ttbr1_el1, x2 // in TTBR1 (since TCR.A1 is set)
171 msr ttbr0_el1, x3 // now update TTBR0
173 b post_ttbr_update_workaround // Back to C code...
174 ENDPROC(cpu_do_switch_mm)
176 .pushsection ".idmap.text", "awx"
178 .macro __idmap_cpu_set_reserved_ttbr1, tmp1, tmp2
179 adrp \tmp1, empty_zero_page
180 phys_to_ttbr \tmp2, \tmp1
189 * void idmap_cpu_replace_ttbr1(phys_addr_t new_pgd)
191 * This is the low-level counterpart to cpu_replace_ttbr1, and should not be
192 * called by anything else. It can only be executed from a TTBR0 mapping.
194 ENTRY(idmap_cpu_replace_ttbr1)
195 save_and_disable_daif flags=x2
197 __idmap_cpu_set_reserved_ttbr1 x1, x3
206 ENDPROC(idmap_cpu_replace_ttbr1)
209 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
210 .pushsection ".idmap.text", "awx"
212 .macro __idmap_kpti_get_pgtable_ent, type
213 dc cvac, cur_\()\type\()p // Ensure any existing dirty
214 dmb sy // lines are written back before
215 ldr \type, [cur_\()\type\()p] // loading the entry
216 tbz \type, #0, skip_\()\type // Skip invalid and
217 tbnz \type, #11, skip_\()\type // non-global entries
220 .macro __idmap_kpti_put_pgtable_ent_ng, type
221 orr \type, \type, #PTE_NG // Same bit for blocks and pages
222 str \type, [cur_\()\type\()p] // Update the entry and ensure
223 dmb sy // that it is visible to all
224 dc civac, cur_\()\type\()p // CPUs.
228 * void __kpti_install_ng_mappings(int cpu, int num_cpus, phys_addr_t swapper)
230 * Called exactly once from stop_machine context by each CPU found during boot.
234 ENTRY(idmap_kpti_install_ng_mappings)
253 mrs swapper_ttb, ttbr1_el1
254 adr flag_ptr, __idmap_kpti_flag
256 cbnz cpu, __idmap_kpti_secondary
258 /* We're the boot CPU. Wait for the others to catch up */
261 ldaxr w18, [flag_ptr]
262 eor w18, w18, num_cpus
265 /* We need to walk swapper, so turn off the MMU. */
266 pre_disable_mmu_workaround
268 bic x18, x18, #SCTLR_ELx_M
272 /* Everybody is enjoying the idmap, so we can rewrite swapper. */
274 mov cur_pgdp, swapper_pa
275 add end_pgdp, cur_pgdp, #(PTRS_PER_PGD * 8)
276 do_pgd: __idmap_kpti_get_pgtable_ent pgd
277 tbnz pgd, #1, walk_puds
279 __idmap_kpti_put_pgtable_ent_ng pgd
281 add cur_pgdp, cur_pgdp, #8
282 cmp cur_pgdp, end_pgdp
285 /* Publish the updated tables and nuke all the TLBs */
291 /* We're done: fire up the MMU again */
293 orr x18, x18, #SCTLR_ELx_M
298 * Invalidate the local I-cache so that any instructions fetched
299 * speculatively from the PoC are discarded, since they may have
300 * been dynamically patched at the PoU.
306 /* Set the flag to zero to indicate that we're all done */
312 .if CONFIG_PGTABLE_LEVELS > 3
313 pte_to_phys cur_pudp, pgd
314 add end_pudp, cur_pudp, #(PTRS_PER_PUD * 8)
315 do_pud: __idmap_kpti_get_pgtable_ent pud
316 tbnz pud, #1, walk_pmds
318 __idmap_kpti_put_pgtable_ent_ng pud
320 add cur_pudp, cur_pudp, 8
321 cmp cur_pudp, end_pudp
324 .else /* CONFIG_PGTABLE_LEVELS <= 3 */
333 .if CONFIG_PGTABLE_LEVELS > 2
334 pte_to_phys cur_pmdp, pud
335 add end_pmdp, cur_pmdp, #(PTRS_PER_PMD * 8)
336 do_pmd: __idmap_kpti_get_pgtable_ent pmd
337 tbnz pmd, #1, walk_ptes
339 __idmap_kpti_put_pgtable_ent_ng pmd
341 add cur_pmdp, cur_pmdp, #8
342 cmp cur_pmdp, end_pmdp
345 .else /* CONFIG_PGTABLE_LEVELS <= 2 */
354 pte_to_phys cur_ptep, pmd
355 add end_ptep, cur_ptep, #(PTRS_PER_PTE * 8)
356 do_pte: __idmap_kpti_get_pgtable_ent pte
357 __idmap_kpti_put_pgtable_ent_ng pte
359 add cur_ptep, cur_ptep, #8
360 cmp cur_ptep, end_ptep
364 /* Secondary CPUs end up here */
365 __idmap_kpti_secondary:
366 /* Uninstall swapper before surgery begins */
367 __idmap_cpu_set_reserved_ttbr1 x18, x17
369 /* Increment the flag to let the boot CPU we're ready */
370 1: ldxr w18, [flag_ptr]
372 stxr w17, w18, [flag_ptr]
375 /* Wait for the boot CPU to finish messing around with swapper */
381 /* All done, act like nothing happened */
382 msr ttbr1_el1, swapper_ttb
403 ENDPROC(idmap_kpti_install_ng_mappings)
410 * Initialise the processor for turning the MMU on. Return in x0 the
411 * value of the SCTLR_EL1 register.
413 .pushsection ".idmap.text", "awx"
415 tlbi vmalle1 // Invalidate local TLB
419 msr cpacr_el1, x0 // Enable FP/ASIMD
420 mov x0, #1 << 12 // Reset mdscr_el1 and disable
421 msr mdscr_el1, x0 // access to the DCC from EL0
422 isb // Unmask debug exceptions now,
423 enable_dbg // since this is per-cpu
424 reset_pmuserenr_el0 x0 // Disable PMU access from EL0
426 * Memory region attributes for LPAE:
430 * DEVICE_nGnRnE 000 00000000
431 * DEVICE_nGnRE 001 00000100
432 * DEVICE_GRE 010 00001100
433 * NORMAL_NC 011 01000100
434 * NORMAL 100 11111111
435 * NORMAL_WT 101 10111011
437 ldr x5, =MAIR(0x00, MT_DEVICE_nGnRnE) | \
438 MAIR(0x04, MT_DEVICE_nGnRE) | \
439 MAIR(0x0c, MT_DEVICE_GRE) | \
440 MAIR(0x44, MT_NORMAL_NC) | \
441 MAIR(0xff, MT_NORMAL) | \
442 MAIR(0xbb, MT_NORMAL_WT)
447 mov_q x0, SCTLR_EL1_SET
449 * Set/prepare TCR and TTBR. We use 512GB (39-bit) address range for
450 * both user and kernel.
452 ldr x10, =TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \
453 TCR_TG_FLAGS | TCR_KASLR_FLAGS | TCR_ASID16 | \
455 tcr_set_idmap_t0sz x10, x9
458 * Set the IPS bits in TCR_EL1.
460 tcr_compute_pa_size x10, #TCR_IPS_SHIFT, x5, x6
461 #ifdef CONFIG_ARM64_HW_AFDBM
463 * Enable hardware update of the Access Flags bit.
464 * Hardware dirty bit management is enabled later,
467 mrs x9, ID_AA64MMFR1_EL1
470 orr x10, x10, #TCR_HA // hardware Access flag update
472 #endif /* CONFIG_ARM64_HW_AFDBM */
474 ret // return to head.S