From 49a3b0e1c05ab3601100a723f7ea207dc99a492a Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 24 Jun 2020 13:23:10 +0100 Subject: arm64: vdso: Only pass --no-eh-frame-hdr when linker supports it Commit 87676cfca141 ("arm64: vdso: Disable dwarf unwinding through the sigreturn trampoline") unconditionally passes the '--no-eh-frame-hdr' option to the linker when building the native vDSO in an attempt to prevent generation of the .eh_frame_hdr section, the presence of which has been implicated in segfaults originating from the libgcc unwinder. Unfortunately, not all versions of binutils support this option, which has been shown to cause build failures in linux-next: | CALL scripts/atomic/check-atomics.sh | CALL scripts/checksyscalls.sh | LD arch/arm64/kernel/vdso/vdso.so.dbg | ld: unrecognized option '--no-eh-frame-hdr' | ld: use the --help option for usage information | arch/arm64/kernel/vdso/Makefile:64: recipe for target | 'arch/arm64/kernel/vdso/vdso.so.dbg' failed | make[1]: *** [arch/arm64/kernel/vdso/vdso.so.dbg] Error 1 | arch/arm64/Makefile:175: recipe for target 'vdso_prepare' failed | make: *** [vdso_prepare] Error 2 Only link the vDSO with '--no-eh-frame-hdr' when the linker supports it. If we end up with the section due to linker defaults, the absence of CFI information in the sigreturn trampoline will prevent the unwinder from breaking. Link: https://lore.kernel.org/r/7a7e31a8-9a7b-2428-ad83-2264f20bdc2d@hisilicon.com Fixes: 87676cfca141 ("arm64: vdso: Disable dwarf unwinding through the sigreturn trampoline") Reported-by: Shaokun Zhang Tested-by: Jon Hunter Signed-off-by: Will Deacon --- arch/arm64/kernel/vdso/Makefile | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index 1e5a940532da..97d3d3632093 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -23,8 +23,9 @@ btildflags-$(CONFIG_ARM64_BTI_KERNEL) += -z force-bti # potential future proofing if we end up with internal calls to the exported # routines, as x86 does (see 6f121e548f83 ("x86, vdso: Reimplement vdso.so # preparation in build-time C")). -ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv \ - -Bsymbolic --no-eh-frame-hdr --build-id -n $(btildflags-y) -T +ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv \ + -Bsymbolic $(call ld-option, --no-eh-frame-hdr) --build-id -n \ + $(btildflags-y) -T ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18 ccflags-y += -DDISABLE_BRANCH_PROFILING -- cgit v1.2.3