Messages in this thread | | | Date | Fri, 27 Mar 2020 12:55:22 +0000 | From | Catalin Marinas <> | Subject | Re: [PATCH 2/2] arm64: Kconfig: ptrauth: Add binutils version check to fix mismatch |
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On Thu, Mar 26, 2020 at 09:02:00PM +0530, Amit Daniel Kachhap wrote: > 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> > --- > arch/arm64/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index e6712b6..73135da 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -1503,7 +1503,7 @@ config ARM64_PTR_AUTH > default y > depends on !KVM || ARM64_VHE > 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) > + depends on (CC_IS_GCC && (GCC_VERSION < 90100 || LD_VERSION >= 233010000)) || (CC_IS_CLANG && AS_HAS_CFI_NEGATE_RA_STATE)
We should add some of the comments in the commit log to the Kconfig entry. I would also split this in two (equivalent to CC_IS_ implies):
depends on !CC_IS_GCC || GCC_VERSION < 90100 || LD_VERSION >= 233010000 depends on !CC_IS_CLANG || AS_HAS_CFI_NEGATE_RA_STATE
and add a comment above the gcc/ld version checking.
(not entirely identical to the original if CC is neither of them but I don't think we have this problem)
-- Catalin
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