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arm64: kernel: use literal for relocated address of __secondary_switched

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We can simply use a relocated 64-bit literal to store the address of
__secondary_switched(), and the relocation code will ensure that it
holds the correct value at secondary entry time, as long as we make sure
that the literal is not dereferenced until after we have enabled the MMU.

So jump via a small __secondary_switch() function covered by the ID map
that performs the literal load and branch-to-register.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
(cherry picked from commit e5ebeec879b726c755af0c1c15f3699b53268cd5)
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
This commit is contained in:
Ard Biesheuvel 2016-04-18 17:09:42 +02:00
parent 7a28120494
commit f7e45d9a0a
1 changed files with 7 additions and 7 deletions
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14
arch/arm64/kernel/head.S
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@ -466,9 +466,7 @@ __mmap_switched:
str x15, [x11, x23]
b 0b
2: adr_l x8, kimage_vaddr // make relocated kimage_vaddr
dc cvac, x8 // value visible to secondaries
dsb sy // with MMU off
2:
#endif
adr_l sp, initial_sp, x4
@ -672,12 +670,9 @@ secondary_startup:
adrp x26, swapper_pg_dir
bl __cpu_setup // initialise processor
ldr x8, kimage_vaddr
ldr w9, 0f
sub x27, x8, w9, sxtw // address to jump to after enabling the MMU
adr_l x27, __secondary_switch // address to jump to after enabling the MMU
b __enable_mmu
ENDPROC(secondary_startup)
0: .long (_text - TEXT_OFFSET) - __secondary_switched
__secondary_switched:
adr_l x5, vectors
@ -750,3 +745,8 @@ __no_granule_support:
wfe
b __no_granule_support
ENDPROC(__no_granule_support)
__secondary_switch:
ldr x8, =__secondary_switched
br x8
ENDPROC(__secondary_switch)