| Message ID | 1437008474-3346-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index ff3bdde..f6fe17d 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -15,6 +15,10 @@ ccflags-y := -shared -fno-common -fno-builtin ccflags-y += -nostdlib -Wl,-soname=linux-vdso.so.1 \ $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) +# Workaround for bare-metal (ELF) toolchains that neglect to pass -shared +# down to collect2, resulting in silent corruption of the vDSO image. +ccflags-y += -Wl,-shared + obj-y += vdso.o extra-y += vdso.lds vdso-offsets.h CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
This is a note to let you know that I have just added a patch titled arm64: vdso: work-around broken ELF toolchains in Makefile to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue This patch is scheduled to be released in version 3.19.y-ckt4. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.19.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 4e3e3116b9e7e45abd5aed73b2737644ef4fc82f Mon Sep 17 00:00:00 2001 From: Will Deacon <will.deacon@arm.com> Date: Fri, 19 Jun 2015 13:56:33 +0100 Subject: arm64: vdso: work-around broken ELF toolchains in Makefile commit 6f1a6ae87c0c60d7c462ef8fd071f291aa7a9abb upstream. When building the kernel with a bare-metal (ELF) toolchain, the -shared option may not be passed down to collect2, resulting in silent corruption of the vDSO image (in particular, the DYNAMIC section is omitted). The effect of this corruption is that the dynamic linker fails to find the vDSO symbols and libc is instead used for the syscalls that we intended to optimise (e.g. gettimeofday). Functionally, there is no issue as the sigreturn trampoline is still intact and located by the kernel. This patch fixes the problem by explicitly passing -shared to the linker when building the vDSO. Reported-by: Szabolcs Nagy <Szabolcs.Nagy@arm.com> Reported-by: James Greenlaigh <james.greenhalgh@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/arm64/kernel/vdso/Makefile | 4 ++++ 1 file changed, 4 insertions(+) -- 1.9.1