From: Amit Daniel Kachhap amit.kachhap@arm.com
mainline inclusion from v5.7-rc1 commit 15cd0e675f3f category: feature bugzilla: 27615 CVE: NA
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Recent addition of ARM64_PTR_AUTH exposed a mismatch issue with binutils. 9.1+ versions of gcc inserts a section note .note.gnu.property but this can be used properly by binutils version greater than 2.33.1. If older binutils are used then the following warnings are generated,
aarch64-linux-ld: warning: arch/arm64/kernel/vdso/vgettimeofday.o: unsupported GNU_PROPERTY_TYPE (5) type: 0xc0000000 aarch64-linux-objdump: warning: arch/arm64/lib/csum.o: unsupported GNU_PROPERTY_TYPE (5) type: 0xc0000000 aarch64-linux-nm: warning: .tmp_vmlinux1: unsupported GNU_PROPERTY_TYPE (5) type: 0xc0000000
This patch enables ARM64_PTR_AUTH when gcc and binutils versions are compatible with each other. Older gcc which do not insert such section continue to work as before.
This scenario may not occur with clang as a recent commit 3b446c7d27ddd06 ("arm64: Kconfig: verify binutils support for ARM64_PTR_AUTH") masks binutils version lesser then 2.34.
Reported-by: kbuild test robot lkp@intel.com Suggested-by: Vincenzo Frascino Vincenzo.Frascino@arm.com Signed-off-by: Amit Daniel Kachhap amit.kachhap@arm.com [catalin.marinas@arm.com: slight adjustment to the comment] Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Reviewed-by: Hanjun Guo guohanjun@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/arm64/Kconfig | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index a9cee77dbfaa4..2b6326901cd3c 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1238,7 +1238,10 @@ config ARM64_PTR_AUTH bool "Enable support for pointer authentication" default y depends on (CC_HAS_SIGN_RETURN_ADDRESS || CC_HAS_BRANCH_PROT_PAC_RET) && AS_HAS_PAC - depends on CC_IS_GCC || (CC_IS_CLANG && AS_HAS_CFI_NEGATE_RA_STATE) + # GCC 9.1 and later inserts a .note.gnu.property section note for PAC + # which is only understood by binutils starting with version 2.33.1. + depends on !CC_IS_GCC || GCC_VERSION < 90100 || LD_VERSION >= 233010000 + depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE depends on (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS) help Pointer authentication (part of the ARMv8.3 Extensions) provides