From 3b446c7d27ddd06342901bb35211363f6944291a Mon Sep 17 00:00:00 2001 From: Nick Desaulniers Date: Thu, 19 Mar 2020 11:19:51 -0700 Subject: [PATCH] arm64: Kconfig: verify binutils support for ARM64_PTR_AUTH Clang relies on GNU as from binutils to assemble the Linux kernel, currently. A recent patch to enable the armv8.3-a extension for pointer authentication checked for compiler support of the relevant flags. Everything works with binutils 2.34+, but for older versions we observe assembler errors: /tmp/vgettimeofday-36a54b.s: Assembler messages: /tmp/vgettimeofday-36a54b.s:40: Error: unknown pseudo-op: `.cfi_negate_ra_state' When compiling with Clang, require the assembler to support .cfi_negate_ra_state directives, in order to support CONFIG_ARM64_PTR_AUTH. Link: https://github.com/ClangBuiltLinux/linux/issues/938 Signed-off-by: Nick Desaulniers Signed-off-by: Catalin Marinas Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor --- arch/arm64/Kconfig | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 155041a..c876afc 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1500,6 +1500,7 @@ 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 (!FUNCTION_GRAPH_TRACER || DYNAMIC_FTRACE_WITH_REGS) help Pointer authentication (part of the ARMv8.3 Extensions) provides @@ -1544,6 +1545,9 @@ config CC_HAS_SIGN_RETURN_ADDRESS config AS_HAS_PAC def_bool $(as-option,-Wa$(comma)-march=armv8.3-a) +config AS_HAS_CFI_NEGATE_RA_STATE + def_bool $(as-instr,.cfi_startproc\n.cfi_negate_ra_state\n.cfi_endproc\n) + endmenu menu "ARMv8.5 architectural features" -- 2.7.4