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linux/arch/arm64/mm/proc.S
Marc Zyngier 8cc8a32415 arm64: Turn the MMU-on sequence into a macro 
Turning the MMU on is a popular sport in the arm64 kernel, and
we do it more than once, or even twice. As we are about to add
even more, let's turn it into a macro.

No expected functional change.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: David Brazdil <dbrazdil@google.com>
Link: https://lore.kernel.org/r/20210208095732.3267263-4-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
2021-02-08 12:51:26 +00:00

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ArmAsm
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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Based on arch/arm/mm/proc.S
*
* Copyright (C) 2001 Deep Blue Solutions Ltd.
* Copyright (C) 2012 ARM Ltd.
* Author: Catalin Marinas <catalin.marinas@arm.com>
*/
#include <linux/init.h>
#include <linux/linkage.h>
#include <linux/pgtable.h>
#include <asm/assembler.h>
#include <asm/asm-offsets.h>
#include <asm/asm_pointer_auth.h>
#include <asm/hwcap.h>
#include <asm/pgtable-hwdef.h>
#include <asm/cpufeature.h>
#include <asm/alternative.h>
#include <asm/smp.h>
#include <asm/sysreg.h>
#ifdef CONFIG_ARM64_64K_PAGES
#define TCR_TG_FLAGS TCR_TG0_64K | TCR_TG1_64K
#elif defined(CONFIG_ARM64_16K_PAGES)
#define TCR_TG_FLAGS TCR_TG0_16K | TCR_TG1_16K
#else /* CONFIG_ARM64_4K_PAGES */
#define TCR_TG_FLAGS TCR_TG0_4K | TCR_TG1_4K
#endif
#ifdef CONFIG_RANDOMIZE_BASE
#define TCR_KASLR_FLAGS TCR_NFD1
#else
#define TCR_KASLR_FLAGS 0
#endif
#define TCR_SMP_FLAGS TCR_SHARED
/* PTWs cacheable, inner/outer WBWA */
#define TCR_CACHE_FLAGS TCR_IRGN_WBWA | TCR_ORGN_WBWA
#ifdef CONFIG_KASAN_SW_TAGS
#define TCR_KASAN_SW_FLAGS TCR_TBI1 | TCR_TBID1
#else
#define TCR_KASAN_SW_FLAGS 0
#endif
#ifdef CONFIG_KASAN_HW_TAGS
#define TCR_KASAN_HW_FLAGS SYS_TCR_EL1_TCMA1 | TCR_TBI1 | TCR_TBID1
#else
#define TCR_KASAN_HW_FLAGS 0
#endif
/*
* Default MAIR_EL1. MT_NORMAL_TAGGED is initially mapped as Normal memory and
* changed during __cpu_setup to Normal Tagged if the system supports MTE.
*/
#define MAIR_EL1_SET \
(MAIR_ATTRIDX(MAIR_ATTR_DEVICE_nGnRnE, MT_DEVICE_nGnRnE) | \
MAIR_ATTRIDX(MAIR_ATTR_DEVICE_nGnRE, MT_DEVICE_nGnRE) | \
MAIR_ATTRIDX(MAIR_ATTR_DEVICE_GRE, MT_DEVICE_GRE) | \
MAIR_ATTRIDX(MAIR_ATTR_NORMAL_NC, MT_NORMAL_NC) | \
MAIR_ATTRIDX(MAIR_ATTR_NORMAL, MT_NORMAL) | \
MAIR_ATTRIDX(MAIR_ATTR_NORMAL_WT, MT_NORMAL_WT) | \
MAIR_ATTRIDX(MAIR_ATTR_NORMAL, MT_NORMAL_TAGGED))
#ifdef CONFIG_CPU_PM
/**
* cpu_do_suspend - save CPU registers context
*
* x0: virtual address of context pointer
*
* This must be kept in sync with struct cpu_suspend_ctx in <asm/suspend.h>.
*/
SYM_FUNC_START(cpu_do_suspend)
mrs x2, tpidr_el0
mrs x3, tpidrro_el0
mrs x4, contextidr_el1
mrs x5, osdlr_el1
mrs x6, cpacr_el1
mrs x7, tcr_el1
mrs x8, vbar_el1
mrs x9, mdscr_el1
mrs x10, oslsr_el1
mrs x11, sctlr_el1
alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
mrs x12, tpidr_el1
alternative_else
mrs x12, tpidr_el2
alternative_endif
mrs x13, sp_el0
stp x2, x3, [x0]
stp x4, x5, [x0, #16]
stp x6, x7, [x0, #32]
stp x8, x9, [x0, #48]
stp x10, x11, [x0, #64]
stp x12, x13, [x0, #80]
/*
* Save x18 as it may be used as a platform register, e.g. by shadow
* call stack.
*/
str x18, [x0, #96]
ret
SYM_FUNC_END(cpu_do_suspend)
/**
* cpu_do_resume - restore CPU register context
*
* x0: Address of context pointer
*/
.pushsection ".idmap.text", "awx"
SYM_FUNC_START(cpu_do_resume)
ldp x2, x3, [x0]
ldp x4, x5, [x0, #16]
ldp x6, x8, [x0, #32]
ldp x9, x10, [x0, #48]
ldp x11, x12, [x0, #64]
ldp x13, x14, [x0, #80]
/*
* Restore x18, as it may be used as a platform register, and clear
* the buffer to minimize the risk of exposure when used for shadow
* call stack.
*/
ldr x18, [x0, #96]
str xzr, [x0, #96]
msr tpidr_el0, x2
msr tpidrro_el0, x3
msr contextidr_el1, x4
msr cpacr_el1, x6
/* Don't change t0sz here, mask those bits when restoring */
mrs x7, tcr_el1
bfi x8, x7, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
msr tcr_el1, x8
msr vbar_el1, x9
/*
* __cpu_setup() cleared MDSCR_EL1.MDE and friends, before unmasking
* debug exceptions. By restoring MDSCR_EL1 here, we may take a debug
* exception. Mask them until local_daif_restore() in cpu_suspend()
* resets them.
*/
disable_daif
msr mdscr_el1, x10
msr sctlr_el1, x12
alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
msr tpidr_el1, x13
alternative_else
msr tpidr_el2, x13
alternative_endif
msr sp_el0, x14
/*
* Restore oslsr_el1 by writing oslar_el1
*/
msr osdlr_el1, x5
ubfx x11, x11, #1, #1
msr oslar_el1, x11
reset_pmuserenr_el0 x0 // Disable PMU access from EL0
reset_amuserenr_el0 x0 // Disable AMU access from EL0
alternative_if ARM64_HAS_RAS_EXTN
msr_s SYS_DISR_EL1, xzr
alternative_else_nop_endif
ptrauth_keys_install_kernel_nosync x14, x1, x2, x3
isb
ret
SYM_FUNC_END(cpu_do_resume)
.popsection
#endif
.pushsection ".idmap.text", "awx"
.macro __idmap_cpu_set_reserved_ttbr1, tmp1, tmp2
adrp \tmp1, reserved_pg_dir
phys_to_ttbr \tmp2, \tmp1
offset_ttbr1 \tmp2, \tmp1
msr ttbr1_el1, \tmp2
isb
tlbi vmalle1
dsb nsh
isb
.endm
/*
* void idmap_cpu_replace_ttbr1(phys_addr_t ttbr1)
*
* This is the low-level counterpart to cpu_replace_ttbr1, and should not be
* called by anything else. It can only be executed from a TTBR0 mapping.
*/
SYM_FUNC_START(idmap_cpu_replace_ttbr1)
save_and_disable_daif flags=x2
__idmap_cpu_set_reserved_ttbr1 x1, x3
offset_ttbr1 x0, x3
msr ttbr1_el1, x0
isb
restore_daif x2
ret
SYM_FUNC_END(idmap_cpu_replace_ttbr1)
.popsection
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
.pushsection ".idmap.text", "awx"
.macro __idmap_kpti_get_pgtable_ent, type
dc cvac, cur_\()\type\()p // Ensure any existing dirty
dmb sy // lines are written back before
ldr \type, [cur_\()\type\()p] // loading the entry
tbz \type, #0, skip_\()\type // Skip invalid and
tbnz \type, #11, skip_\()\type // non-global entries
.endm
.macro __idmap_kpti_put_pgtable_ent_ng, type
orr \type, \type, #PTE_NG // Same bit for blocks and pages
str \type, [cur_\()\type\()p] // Update the entry and ensure
dmb sy // that it is visible to all
dc civac, cur_\()\type\()p // CPUs.
.endm
/*
* void __kpti_install_ng_mappings(int cpu, int num_cpus, phys_addr_t swapper)
*
* Called exactly once from stop_machine context by each CPU found during boot.
*/
__idmap_kpti_flag:
.long 1
SYM_FUNC_START(idmap_kpti_install_ng_mappings)
cpu .req w0
num_cpus .req w1
swapper_pa .req x2
swapper_ttb .req x3
flag_ptr .req x4
cur_pgdp .req x5
end_pgdp .req x6
pgd .req x7
cur_pudp .req x8
end_pudp .req x9
pud .req x10
cur_pmdp .req x11
end_pmdp .req x12
pmd .req x13
cur_ptep .req x14
end_ptep .req x15
pte .req x16
mrs swapper_ttb, ttbr1_el1
restore_ttbr1 swapper_ttb
adr flag_ptr, __idmap_kpti_flag
cbnz cpu, __idmap_kpti_secondary
/* We're the boot CPU. Wait for the others to catch up */
sevl
1: wfe
ldaxr w17, [flag_ptr]
eor w17, w17, num_cpus
cbnz w17, 1b
/* We need to walk swapper, so turn off the MMU. */
pre_disable_mmu_workaround
mrs x17, sctlr_el1
bic x17, x17, #SCTLR_ELx_M
msr sctlr_el1, x17
isb
/* Everybody is enjoying the idmap, so we can rewrite swapper. */
/* PGD */
mov cur_pgdp, swapper_pa
add end_pgdp, cur_pgdp, #(PTRS_PER_PGD * 8)
do_pgd: __idmap_kpti_get_pgtable_ent pgd
tbnz pgd, #1, walk_puds
next_pgd:
__idmap_kpti_put_pgtable_ent_ng pgd
skip_pgd:
add cur_pgdp, cur_pgdp, #8
cmp cur_pgdp, end_pgdp
b.ne do_pgd
/* Publish the updated tables and nuke all the TLBs */
dsb sy
tlbi vmalle1is
dsb ish
isb
/* We're done: fire up the MMU again */
mrs x17, sctlr_el1
orr x17, x17, #SCTLR_ELx_M
set_sctlr_el1 x17
/* Set the flag to zero to indicate that we're all done */
str wzr, [flag_ptr]
ret
/* PUD */
walk_puds:
.if CONFIG_PGTABLE_LEVELS > 3
pte_to_phys cur_pudp, pgd
add end_pudp, cur_pudp, #(PTRS_PER_PUD * 8)
do_pud: __idmap_kpti_get_pgtable_ent pud
tbnz pud, #1, walk_pmds
next_pud:
__idmap_kpti_put_pgtable_ent_ng pud
skip_pud:
add cur_pudp, cur_pudp, 8
cmp cur_pudp, end_pudp
b.ne do_pud
b next_pgd
.else /* CONFIG_PGTABLE_LEVELS <= 3 */
mov pud, pgd
b walk_pmds
next_pud:
b next_pgd
.endif
/* PMD */
walk_pmds:
.if CONFIG_PGTABLE_LEVELS > 2
pte_to_phys cur_pmdp, pud
add end_pmdp, cur_pmdp, #(PTRS_PER_PMD * 8)
do_pmd: __idmap_kpti_get_pgtable_ent pmd
tbnz pmd, #1, walk_ptes
next_pmd:
__idmap_kpti_put_pgtable_ent_ng pmd
skip_pmd:
add cur_pmdp, cur_pmdp, #8
cmp cur_pmdp, end_pmdp
b.ne do_pmd
b next_pud
.else /* CONFIG_PGTABLE_LEVELS <= 2 */
mov pmd, pud
b walk_ptes
next_pmd:
b next_pud
.endif
/* PTE */
walk_ptes:
pte_to_phys cur_ptep, pmd
add end_ptep, cur_ptep, #(PTRS_PER_PTE * 8)
do_pte: __idmap_kpti_get_pgtable_ent pte
__idmap_kpti_put_pgtable_ent_ng pte
skip_pte:
add cur_ptep, cur_ptep, #8
cmp cur_ptep, end_ptep
b.ne do_pte
b next_pmd
.unreq cpu
.unreq num_cpus
.unreq swapper_pa
.unreq cur_pgdp
.unreq end_pgdp
.unreq pgd
.unreq cur_pudp
.unreq end_pudp
.unreq pud
.unreq cur_pmdp
.unreq end_pmdp
.unreq pmd
.unreq cur_ptep
.unreq end_ptep
.unreq pte
/* Secondary CPUs end up here */
__idmap_kpti_secondary:
/* Uninstall swapper before surgery begins */
__idmap_cpu_set_reserved_ttbr1 x16, x17
/* Increment the flag to let the boot CPU we're ready */
1: ldxr w16, [flag_ptr]
add w16, w16, #1
stxr w17, w16, [flag_ptr]
cbnz w17, 1b
/* Wait for the boot CPU to finish messing around with swapper */
sevl
1: wfe
ldxr w16, [flag_ptr]
cbnz w16, 1b
/* All done, act like nothing happened */
offset_ttbr1 swapper_ttb, x16
msr ttbr1_el1, swapper_ttb
isb
ret
.unreq swapper_ttb
.unreq flag_ptr
SYM_FUNC_END(idmap_kpti_install_ng_mappings)
.popsection
#endif
/*
* __cpu_setup
*
* Initialise the processor for turning the MMU on.
*
* Output:
* Return in x0 the value of the SCTLR_EL1 register.
*/
.pushsection ".idmap.text", "awx"
SYM_FUNC_START(__cpu_setup)
tlbi vmalle1 // Invalidate local TLB
dsb nsh
mov x1, #3 << 20
msr cpacr_el1, x1 // Enable FP/ASIMD
mov x1, #1 << 12 // Reset mdscr_el1 and disable
msr mdscr_el1, x1 // access to the DCC from EL0
isb // Unmask debug exceptions now,
enable_dbg // since this is per-cpu
reset_pmuserenr_el0 x1 // Disable PMU access from EL0
reset_amuserenr_el0 x1 // Disable AMU access from EL0
/*
* Memory region attributes
*/
mov_q x5, MAIR_EL1_SET
#ifdef CONFIG_ARM64_MTE
mte_tcr .req x20
mov mte_tcr, #0
/*
* Update MAIR_EL1, GCR_EL1 and TFSR*_EL1 if MTE is supported
* (ID_AA64PFR1_EL1[11:8] > 1).
*/
mrs x10, ID_AA64PFR1_EL1
ubfx x10, x10, #ID_AA64PFR1_MTE_SHIFT, #4
cmp x10, #ID_AA64PFR1_MTE
b.lt 1f
/* Normal Tagged memory type at the corresponding MAIR index */
mov x10, #MAIR_ATTR_NORMAL_TAGGED
bfi x5, x10, #(8 * MT_NORMAL_TAGGED), #8
/* initialize GCR_EL1: all non-zero tags excluded by default */
mov x10, #(SYS_GCR_EL1_RRND | SYS_GCR_EL1_EXCL_MASK)
msr_s SYS_GCR_EL1, x10
/* clear any pending tag check faults in TFSR*_EL1 */
msr_s SYS_TFSR_EL1, xzr
msr_s SYS_TFSRE0_EL1, xzr
/* set the TCR_EL1 bits */
mov_q mte_tcr, TCR_KASAN_HW_FLAGS
1:
#endif
msr mair_el1, x5
/*
* Set/prepare TCR and TTBR. TCR_EL1.T1SZ gets further
* adjusted if the kernel is compiled with 52bit VA support.
*/
mov_q x10, TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \
TCR_TG_FLAGS | TCR_KASLR_FLAGS | TCR_ASID16 | \
TCR_TBI0 | TCR_A1 | TCR_KASAN_SW_FLAGS
#ifdef CONFIG_ARM64_MTE
orr x10, x10, mte_tcr
.unreq mte_tcr
#endif
tcr_clear_errata_bits x10, x9, x5
#ifdef CONFIG_ARM64_VA_BITS_52
ldr_l x9, vabits_actual
sub x9, xzr, x9
add x9, x9, #64
tcr_set_t1sz x10, x9
#else
ldr_l x9, idmap_t0sz
#endif
tcr_set_t0sz x10, x9
/*
* Set the IPS bits in TCR_EL1.
*/
tcr_compute_pa_size x10, #TCR_IPS_SHIFT, x5, x6
#ifdef CONFIG_ARM64_HW_AFDBM
/*
* Enable hardware update of the Access Flags bit.
* Hardware dirty bit management is enabled later,
* via capabilities.
*/
mrs x9, ID_AA64MMFR1_EL1
and x9, x9, #0xf
cbz x9, 1f
orr x10, x10, #TCR_HA // hardware Access flag update
1:
#endif /* CONFIG_ARM64_HW_AFDBM */
msr tcr_el1, x10
/*
* Prepare SCTLR
*/
mov_q x0, INIT_SCTLR_EL1_MMU_ON
ret // return to head.S
SYM_FUNC_END(__cpu_setup)
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