From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Mon, 4 Apr 2016 16:52:23 +0200 Subject: [PATCH 7/8] arm64/kernel: drop __PHYS_OFFSET register with file scope from head.S In-Reply-To: <1459781544-14310-1-git-send-email-ard.biesheuvel@linaro.org> References: <1459781544-14310-1-git-send-email-ard.biesheuvel@linaro.org> Message-ID: <1459781544-14310-8-git-send-email-ard.biesheuvel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Instead of keeping __PHYS_OFFSET in a callee saved register with file scope in head.S, derive the value on demand. This makes for cleaner and more maintainable code. Signed-off-by: Ard Biesheuvel --- arch/arm64/kernel/head.S | 26 +++++++++++--------- 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index d28fc345bec3..23d03da7ecfe 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -213,7 +213,6 @@ ENTRY(stext) bl preserve_boot_args bl el2_setup // Drop to EL1, w0=cpu_boot_mode mov x23, xzr // KASLR offset, defaults to 0 - adrp x24, __PHYS_OFFSET bl set_cpu_boot_mode_flag bl __create_page_tables /* @@ -396,7 +395,7 @@ __create_page_tables: create_pgd_entry x0, x5, x3, x6 ldr w6, kernel_img_size add x6, x6, x5 - mov x3, x24 // phys offset + adrp x3, __PHYS_OFFSET create_block_map x0, x7, x3, x5, x6 /* @@ -417,7 +416,7 @@ kernel_img_size: .ltorg /* - * The following fragment of code is executed with the MMU enabled. + * __mmap_switched(u64 phys_offset) - virtual entry point for the boot CPU */ __mmap_switched: adrp x4, init_thread_union @@ -431,14 +430,6 @@ __mmap_switched: msr vbar_el1, x8 // vector table address isb - // Clear BSS - adr_l x0, __bss_start - mov x1, xzr - adr_l x2, __bss_stop - sub x2, x2, x0 - bl __pi_memset - dsb ishst // Make zero page visible to PTW - #ifdef CONFIG_RELOCATABLE /* @@ -479,8 +470,17 @@ __mmap_switched: #endif ldr_l x4, kimage_vaddr // Save the offset between - sub x4, x4, x24 // the kernel virtual and + 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 + adr_l x2, __bss_stop + sub x2, x2, x0 + bl __pi_memset + dsb ishst // Make zero page visible to PTW + #ifdef CONFIG_KASAN bl kasan_early_init #endif @@ -774,6 +774,7 @@ __enable_mmu: mov x20, x1 // preserve branch target #ifdef CONFIG_RANDOMIZE_BASE mov x19, x0 // preserve new SCTLR_EL1 value + adrp x0, __PHYS_OFFSET blr x1 /* @@ -792,6 +793,7 @@ __enable_mmu: isb add x20, x20, x23 // relocated __mmap_switched #endif + adrp x0, __PHYS_OFFSET br x20 ENDPROC(__enable_mmu) -- 2.5.0