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arm64: kernel: drop use of x24 from primary boot path

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Keeping __PHYS_OFFSET in x24 is actually less clear than simply taking
the value of __PHYS_OFFSET using an adrp instruction in the three places
that we need it. So change that.

Reviewed-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 2016-08-31 12:05:15 +01:00 committed by Will Deacon
parent 9dcf7914ae
commit b929fe320e
1 changed files with 12 additions and 8 deletions
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20
arch/arm64/kernel/head.S
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@ -211,8 +211,8 @@ efi_header_end:
ENTRY(stext)
bl preserve_boot_args
bl el2_setup // Drop to EL1, w0=cpu_boot_mode
adrp x24, __PHYS_OFFSET
and x23, x24, MIN_KIMG_ALIGN - 1 // KASLR offset, defaults to 0
adrp x23, __PHYS_OFFSET
and x23, x23, MIN_KIMG_ALIGN - 1 // KASLR offset, defaults to 0
bl set_cpu_boot_mode_flag
bl __create_page_tables
/*
@ -412,6 +412,8 @@ ENDPROC(__create_page_tables)
/*
* The following fragment of code is executed with the MMU enabled.
*
* x0 = __PHYS_OFFSET
*/
.set initial_sp, init_thread_union + THREAD_START_SP
__primary_switched:
@ -420,6 +422,12 @@ __primary_switched:
msr vbar_el1, x8 // vector table address
isb
str_l x21, __fdt_pointer, x5 // Save FDT pointer
ldr_l x4, kimage_vaddr // Save the offset between
sub x4, x4, x0 // the kernel virtual and
str_l x4, kimage_voffset, x5 // physical mappings
// Clear BSS
adr_l x0, __bss_start
mov x1, xzr
@ -432,12 +440,6 @@ __primary_switched:
mov x4, sp
and x4, x4, #~(THREAD_SIZE - 1)
msr sp_el0, x4 // Save thread_info
str_l x21, __fdt_pointer, x5 // Save FDT pointer
ldr_l x4, kimage_vaddr // Save the offset between
sub x4, x4, x24 // the kernel virtual and
str_l x4, kimage_voffset, x5 // physical mappings
mov x29, #0
#ifdef CONFIG_KASAN
bl kasan_early_init
@ -794,6 +796,7 @@ __primary_switch:
bl __relocate_kernel
#ifdef CONFIG_RANDOMIZE_BASE
ldr x8, =__primary_switched
adrp x0, __PHYS_OFFSET
blr x8
/*
@ -818,5 +821,6 @@ __primary_switch:
#endif
#endif
ldr x8, =__primary_switched
adrp x0, __PHYS_OFFSET
br x8
ENDPROC(__primary_switch)