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| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2017-02-15 15:11:13 +0000 |
|---|---|---|
| committer | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2017-05-30 20:54:51 +0000 |
| commit | 95209863a4df2eaeaad1f176b2f3bae6774b09b5 (patch) | |
| tree | 8b0a4131f1455e511dc5537130bb97ec59e7c356 | |
| parent | 327ec1603ba23834b9394b659753df7947d7b5ec (diff) | |
| download | linux-arm64-no-rwx.tar.gz | |
arm64: efi: use effective text offset when allocating Imagearm64-no-rwx
Update the image allocation logic in the EFI stub so that the effective
text offset is always honoured on 4 KB pagesize kernels. This ensures
that the __init segment can be mapped without resorting to early RWX
mappings.
Note that this sacrifices 5 bits of KASLR randomization on such kernels.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
| -rw-r--r-- | arch/arm64/kernel/efi-entry.S | 5 | ||||
| -rw-r--r-- | arch/arm64/kernel/image.h | 1 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/Makefile | 1 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/arm64-stub.c | 14 |
4 files changed, 15 insertions, 6 deletions
diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S index 4e6ad355bd058e..4e1cbec3c842ce 100644 --- a/arch/arm64/kernel/efi-entry.S +++ b/arch/arm64/kernel/efi-entry.S @@ -120,3 +120,8 @@ efi_load_fail: entry_end: ENDPROC(entry) + + __INITRODATA + .align 2 +ENTRY(effective_text_offset) + .long __eff_text_offset diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h index 98e191cd97b121..f137856f50bf33 100644 --- a/arch/arm64/kernel/image.h +++ b/arch/arm64/kernel/image.h @@ -132,6 +132,7 @@ __efistub__text = KALLSYMS_HIDE(_text); __efistub__end = KALLSYMS_HIDE(_end); __efistub__edata = KALLSYMS_HIDE(_edata); __efistub_screen_info = KALLSYMS_HIDE(screen_info); +__efistub___eff_text_offset = KALLSYMS_HIDE(__eff_text_offset); #endif diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index f7425960f6a57d..1563d5e5972779 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -41,7 +41,6 @@ lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o random.o \ lib-$(CONFIG_ARM) += arm32-stub.o lib-$(CONFIG_ARM64) += arm64-stub.o -CFLAGS_arm64-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET) # # arm64 puts the stub in the kernel proper, which will unnecessarily retain all diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c index b4c2589d7c9127..bc724fc0b77027 100644 --- a/drivers/firmware/efi/libstub/arm64-stub.c +++ b/drivers/firmware/efi/libstub/arm64-stub.c @@ -16,6 +16,8 @@ #include "efistub.h" +extern const u32 effective_text_offset; + efi_status_t check_platform_features(efi_system_table_t *sys_table_arg) { u64 tg; @@ -70,7 +72,8 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table_arg, * a 2 MB aligned base, which itself may be lower than dram_base, as * long as the resulting offset equals or exceeds it. */ - preferred_offset = round_down(dram_base, MIN_KIMG_ALIGN) + TEXT_OFFSET; + preferred_offset = round_down(dram_base, MIN_KIMG_ALIGN) + + effective_text_offset; if (preferred_offset < dram_base) preferred_offset += MIN_KIMG_ALIGN; @@ -84,8 +87,9 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table_arg, * is a multiple of the minimal segment alignment (SZ_64K) */ u32 mask = (MIN_KIMG_ALIGN - 1) & ~(SZ_64K - 1); - u32 offset = !IS_ENABLED(CONFIG_DEBUG_ALIGN_RODATA) ? - (phys_seed >> 32) & mask : TEXT_OFFSET; + u32 offset = (!IS_ENABLED(CONFIG_DEBUG_ALIGN_RODATA) && + PAGE_SIZE > SZ_4K) ? (phys_seed >> 32) & mask : + effective_text_offset; /* * If KASLR is enabled, and we have some randomness available, @@ -122,7 +126,7 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table_arg, } if (status != EFI_SUCCESS) { - *reserve_size = kernel_memsize + TEXT_OFFSET; + *reserve_size = kernel_memsize + effective_text_offset; status = efi_low_alloc(sys_table_arg, *reserve_size, MIN_KIMG_ALIGN, reserve_addr); @@ -131,7 +135,7 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table_arg, *reserve_size = 0; return status; } - *image_addr = *reserve_addr + TEXT_OFFSET; + *image_addr = *reserve_addr + effective_text_offset; } memcpy((void *)*image_addr, old_image_addr, kernel_size); |