diff options
| author | Peter Collingbourne <pcc@google.com> | 2018-11-06 16:39:13 -0800 |
|---|---|---|
| committer | Davide Garberi <dade.garberi@gmail.com> | 2021-10-07 16:16:12 +0200 |
| commit | 58a16b930a5d095c87db32b2c691b403daadbe4c (patch) | |
| tree | c72c57eda2651c2fdf21836aa303743dc02e2deb | |
| parent | 2702a0b636324a6c6bd4176588b10f2adc122361 (diff) | |
FROMLIST: arm64: Build vDSO with -ffixed-x18
The vDSO needs to be build with x18 reserved in order to accommodate
userspace platform ABIs built on top of Linux that use the register
to carry inter-procedural state, as provided for by the AAPCS.
An example of such a platform ABI is the one that will be used by an
upcoming version of Android.
Although this change is currently a no-op due to the fact that the vDSO
is currently implemented in pure assembly on arm64, it is necessary
in order to prepare for another change [1] that will add C code to
the vDSO.
[1] https://patchwork.kernel.org/patch/10044501/
Change-Id: Icaac4b1c9127d81d754d3b8688274e9afc781760
Signed-off-by: Peter Collingbourne <pcc@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Mark Salyzyn <salyzyn@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
| -rw-r--r-- | arch/arm64/kernel/vdso/Makefile | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index 83deb2a47de5..4adcb532ac6a 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -15,7 +15,7 @@ obj-vdso-c := $(addprefix $(obj)/, $(obj-vdso-c)) obj-vdso := $(obj-vdso-c) $(obj-vdso-s) ccflags-y := -shared -fno-common -fno-builtin -fno-stack-protector -ccflags-y += -DDISABLE_BRANCH_PROFILING +ccflags-y += -DDISABLE_BRANCH_PROFILING -ffixed-x18 ccflags-y += -nostdlib -Wl,-soname=linux-vdso.so.1 \ $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) |