diff options
| author | Xiu Jianfeng <xiujianfeng@huawei.com> | 2022-07-01 16:24:35 +0800 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2022-07-28 16:22:15 +1000 |
| commit | f4a0318f278d98d9492916722e85f258c2221f88 (patch) | |
| tree | e1526c00daeb382c4e4af213fef62c74c5551796 /arch/powerpc/kernel/Makefile | |
| parent | 1547db7d1f4481c1f3ec731f3edc724ef3026ede (diff) | |
powerpc: add support for syscall stack randomization
Add support for adding a random offset to the stack while handling
syscalls. This patch uses mftb() instead of get_random_int() for better
performance.
In order to avoid unconditional stack canaries on syscall entry (due to
the use of alloca()), also disable stack protector to avoid triggering
needless checks and slowing down the entry path. As there is no general
way to control stack protector coverage with a function attribute, this
must be disabled at the compilation unit level.
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220701082435.126596-3-xiujianfeng@huawei.com
Diffstat (limited to 'arch/powerpc/kernel/Makefile')
| -rw-r--r-- | arch/powerpc/kernel/Makefile | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index 0963d39464c8..06d2d1f78f71 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -54,6 +54,13 @@ CFLAGS_cputable.o += -DDISABLE_BRANCH_PROFILING CFLAGS_btext.o += -DDISABLE_BRANCH_PROFILING endif +#ifdef CONFIG_RANDOMIZE_KSTACK_OFFSET +# Remove stack protector to avoid triggering unneeded stack canary +# checks due to randomize_kstack_offset. +CFLAGS_REMOVE_syscall.o = -fstack-protector -fstack-protector-strong +CFLAGS_syscall.o += -fno-stack-protector +#endif + obj-y := cputable.o syscalls.o \ irq.o align.o signal_$(BITS).o pmc.o vdso.o \ process.o systbl.o idle.o \ |