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| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2016-08-31 12:05:15 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2016-09-02 11:47:51 +0100 |
| commit | b929fe320e5f3c91c76cca81be80f2dde2ac54a6 (patch) | |
| tree | 32bc17cf1db2da58f61392d5f17e76dbf058624e /arch/arm64/kernel/head.S | |
| parent | 9dcf7914ae238619ae019dcf82a91c817ff8628e (diff) | |
| download | lwn-b929fe320e5f3c91c76cca81be80f2dde2ac54a6.tar.gz lwn-b929fe320e5f3c91c76cca81be80f2dde2ac54a6.zip | |
arm64: kernel: drop use of x24 from primary boot path
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>
Diffstat (limited to 'arch/arm64/kernel/head.S')
| -rw-r--r-- | arch/arm64/kernel/head.S | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 45b865e022cc..4dee51045e79 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -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) |