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ARM: mm: switch to swapper_pg_dir early for vmap'ed stack

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When onlining a CPU, switch to swapper_pg_dir as soon as possible so
that it is guaranteed that the vmap'ed stack is mapped before it is
used.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Ard Biesheuvel 2022-01-24 19:51:58 +01:00
parent 5fe41793bc
commit 8b806b82bc
3 changed files with 15 additions and 1 deletions
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2
arch/arm/Kconfig
View File

@ -128,7 +128,7 @@ config ARM
select RTC_LIB
select SYS_SUPPORTS_APM_EMULATION
select THREAD_INFO_IN_TASK
select HAVE_ARCH_VMAP_STACK if MMU && (!LD_IS_LLD || LLD_VERSION >= 140000) && !PM_SLEEP_SMP
select HAVE_ARCH_VMAP_STACK if MMU && (!LD_IS_LLD || LLD_VERSION >= 140000)
select TRACE_IRQFLAGS_SUPPORT if !CPU_V7M
# Above selects are sorted alphabetically; please add new ones
# according to that. Thanks.

7
arch/arm/kernel/head.S
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@ -424,6 +424,13 @@ ENDPROC(secondary_startup)
ENDPROC(secondary_startup_arm)
ENTRY(__secondary_switched)
#if defined(CONFIG_VMAP_STACK) && !defined(CONFIG_ARM_LPAE)
@ Before using the vmap'ed stack, we have to switch to swapper_pg_dir
@ as the ID map does not cover the vmalloc region.
mrc p15, 0, ip, c2, c0, 1 @ read TTBR1
mcr p15, 0, ip, c2, c0, 0 @ set TTBR0
instr_sync
#endif
adr_l r7, secondary_data + 12 @ get secondary_data.stack
ldr sp, [r7]
ldr r0, [r7, #4] @ get secondary_data.task

7
arch/arm/kernel/sleep.S
View File

@ -119,6 +119,13 @@ ENTRY(cpu_resume_mmu)
ENDPROC(cpu_resume_mmu)
.popsection
cpu_resume_after_mmu:
#if defined(CONFIG_VMAP_STACK) && !defined(CONFIG_ARM_LPAE)
@ Before using the vmap'ed stack, we have to switch to swapper_pg_dir
@ as the ID map does not cover the vmalloc region.
mrc p15, 0, ip, c2, c0, 1 @ read TTBR1
mcr p15, 0, ip, c2, c0, 0 @ set TTBR0
instr_sync
#endif
bl cpu_init @ restore the und/abt/irq banked regs
mov r0, #0 @ return zero on success
ldmfd sp!, {r4 - r11, pc}