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arm64: head.S: move KASLR processing out of __enable_mmu() 

The KASLR processing is only used by the primary boot path, and
complements the processing that takes place in __primary_switch().
Move the two parts together, to make the code easier to understand.

Also, fix up a minor whitespace issue.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[will: fixed conflict with -rc3 due to lack of fd363bd417]
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Ard Biesheuvel 2016-08-31 12:05:13 +01:00 committed by Will Deacon
parent 23c8a500c2
commit 3c5e9f238b
1 changed files with 42 additions and 27 deletions
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69
arch/arm64/kernel/head.S
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@ -222,9 +222,7 @@ ENTRY(stext)
* the TCR will have been set.
*/
bl __cpu_setup // initialise processor
adr_l x27, __primary_switch // address to jump to after
// MMU has been enabled
b __enable_mmu
b __primary_switch
ENDPROC(stext)
/*
@ -453,7 +451,7 @@ __primary_switched:
cbz x0, 0f // KASLR disabled? just proceed
orr x23, x23, x0 // record KASLR offset
ret x28 // we must enable KASLR, return
// to __enable_mmu()
// to __primary_switch()
0:
#endif
b start_kernel
@ -726,7 +724,6 @@ ENDPROC(__secondary_switched)
* If it isn't, park the CPU
*/
ENTRY(__enable_mmu)
mrs x22, sctlr_el1 // preserve old SCTLR_EL1 value
mrs x1, ID_AA64MMFR0_EL1
ubfx x2, x1, #ID_AA64MMFR0_TGRAN_SHIFT, 4
cmp x2, #ID_AA64MMFR0_TGRAN_SUPPORTED
@ -747,25 +744,6 @@ ENTRY(__enable_mmu)
ic iallu
dsb nsh
isb
#ifdef CONFIG_RANDOMIZE_BASE
mov x19, x0 // preserve new SCTLR_EL1 value
blr x27
/*
* If we return here, we have a KASLR displacement in x23 which we need
* to take into account by discarding the current kernel mapping and
* creating a new one.
*/
msr sctlr_el1, x22 // disable the MMU
isb
bl __create_page_tables // recreate kernel mapping
msr sctlr_el1, x19 // re-enable the MMU
isb
ic iallu // flush instructions fetched
dsb nsh // via old mapping
isb
#endif
br x27
ENDPROC(__enable_mmu)
@ -775,11 +753,11 @@ __no_granule_support:
1:
wfe
wfi
b 1b
b 1b
ENDPROC(__no_granule_support)
__primary_switch:
#ifdef CONFIG_RELOCATABLE
__relocate_kernel:
/*
* Iterate over each entry in the relocation table, and apply the
* relocations in place.
@ -801,8 +779,45 @@ __primary_switch:
add x13, x13, x23 // relocate
str x13, [x11, x23]
b 0b
1: ret
ENDPROC(__relocate_kernel)
#endif
1:
__primary_switch:
#ifdef CONFIG_RANDOMIZE_BASE
mov x19, x0 // preserve new SCTLR_EL1 value
mrs x20, sctlr_el1 // preserve old SCTLR_EL1 value
#endif
adr x27, 0f
b __enable_mmu
0:
#ifdef CONFIG_RELOCATABLE
bl __relocate_kernel
#ifdef CONFIG_RANDOMIZE_BASE
ldr x8, =__primary_switched
blr x8
/*
* If we return here, we have a KASLR displacement in x23 which we need
* to take into account by discarding the current kernel mapping and
* creating a new one.
*/
msr sctlr_el1, x20 // disable the MMU
isb
bl __create_page_tables // recreate kernel mapping
tlbi vmalle1 // Remove any stale TLB entries
dsb nsh
msr sctlr_el1, x19 // re-enable the MMU
isb
ic iallu // flush instructions fetched
dsb nsh // via old mapping
isb
bl __relocate_kernel
#endif
#endif
ldr x8, =__primary_switched
br x8