Re: [PATCH v3 3/9] efi/libstub: Remove .note.gnu.property
From: Fangrui Song <hidden>
Date: 2020-06-24 03:31:49
Also in:
linux-arch, linux-efi, lkml
On 2020-06-23, Kees Cook wrote:
quoted hunk ↗ jump to hunk
In preparation for adding --orphan-handling=warn to more architectures, make sure unwanted sections don't end up appearing under the .init section prefix that libstub adds to itself during objcopy. Signed-off-by: Kees Cook <redacted> --- drivers/firmware/efi/libstub/Makefile | 3 +++ 1 file changed, 3 insertions(+)diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index 75daaf20374e..9d2d2e784bca 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile@@ -66,6 +66,9 @@ lib-$(CONFIG_X86) += x86-stub.oCFLAGS_arm32-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET) CFLAGS_arm64-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET) +# Remove unwanted sections first. +STUBCOPY_FLAGS-y += --remove-section=.note.gnu.property + # # For x86, bootloaders like systemd-boot or grub-efi do not zero-initialize the # .bss section, so the .bss section of the EFI stub needs to be included in the
arch/arm64/Kconfig enables ARM64_PTR_AUTH by default. When the config is on
ifeq ($(CONFIG_ARM64_BTI_KERNEL),y)
branch-prot-flags-$(CONFIG_CC_HAS_BRANCH_PROT_PAC_RET_BTI) := -mbranch-protection=pac-ret+leaf+bti
else
branch-prot-flags-$(CONFIG_CC_HAS_BRANCH_PROT_PAC_RET) := -mbranch-protection=pac-ret+leaf
endif
This option creates .note.gnu.property:
% readelf -n drivers/firmware/efi/libstub/efi-stub.o
Displaying notes found in: .note.gnu.property
Owner Data size Description
GNU 0x00000010 NT_GNU_PROPERTY_TYPE_0
Properties: AArch64 feature: PAC
If .note.gnu.property is not desired in drivers/firmware/efi/libstub, specifying
-mbranch-protection=none can override -mbranch-protection=pac-ret+leaf
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