iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

arm64: kernel: use literal for relocated address of __secondary_switched

Browse Source 
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>
This commit is contained in:
Ard Biesheuvel 2016-04-18 17:09:42 +02:00 committed by Will Deacon
parent 190c056fc3
commit e5ebeec879
1 changed files with 7 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
arch/arm64/kernel/head.S
View File

@ -468,9 +468,7 @@ __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
@ -699,12 +697,9 @@ 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
@ -806,3 +801,8 @@ __no_granule_support:
wfi
b 1b
ENDPROC(__no_granule_support)
__secondary_switch:
ldr x8, =__secondary_switched
br x8
ENDPROC(__secondary_switch)