diff options
| author | Nick Desaulniers <ndesaulniers@google.com> | 2020-03-19 11:19:51 -0700 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2020-03-20 15:01:04 +0000 |
| commit | 3b446c7d27ddd06342901bb35211363f6944291a (patch) | |
| tree | 4b12fffedeee42e3d9242409c51eb585c9e1b0e5 /arch/arm64/Kconfig | |
| parent | 6cb6982f42cbfaf5e50af1069451a8828231ffb9 (diff) | |
| download | lwn-3b446c7d27ddd06342901bb35211363f6944291a.tar.gz lwn-3b446c7d27ddd06342901bb35211363f6944291a.zip | |
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 <ndesaulniers@google.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Diffstat (limited to 'arch/arm64/Kconfig')
| -rw-r--r-- | arch/arm64/Kconfig | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 155041a5f0e4..c876afce10f3 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" |