summaryrefslogtreecommitdiff
path: root/arch/x86/um
diff options
context:
space:
mode:
authorAmmar Faizi <ammarfaizi2@gnuweeb.org>2022-12-23 20:23:38 +0300
committerRichard Weinberger <richard@nod.at>2023-02-10 23:33:37 +0300
commit5541992e512de8c9133110809f767bd1b54ee10d (patch)
treed9b457237b4bf9ead98a7f9ade2c9a80d60161bf /arch/x86/um
parent0438aadfa69a345136f5ba4f582e0f769450ee0d (diff)
downloadlinux-5541992e512de8c9133110809f767bd1b54ee10d.tar.xz
x86: um: vdso: Add '%rcx' and '%r11' to the syscall clobber list
The 'syscall' instruction clobbers '%rcx' and '%r11', but they are not listed in the inline Assembly that performs the syscall instruction. No real bug is found. It wasn't buggy by luck because '%rcx' and '%r11' are caller-saved registers, and not used in the functions, and the functions are never inlined. Add them to the clobber list for code correctness. Fixes: f1c2bb8b9964ed31de988910f8b1cfb586d30091 ("um: implement a x86_64 vDSO") Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org> Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/x86/um')
-rw-r--r--arch/x86/um/vdso/um_vdso.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/arch/x86/um/vdso/um_vdso.c b/arch/x86/um/vdso/um_vdso.c
index 2112b8d14668..ff0f3b4b6c45 100644
--- a/arch/x86/um/vdso/um_vdso.c
+++ b/arch/x86/um/vdso/um_vdso.c
@@ -17,8 +17,10 @@ int __vdso_clock_gettime(clockid_t clock, struct __kernel_old_timespec *ts)
{
long ret;
- asm("syscall" : "=a" (ret) :
- "0" (__NR_clock_gettime), "D" (clock), "S" (ts) : "memory");
+ asm("syscall"
+ : "=a" (ret)
+ : "0" (__NR_clock_gettime), "D" (clock), "S" (ts)
+ : "rcx", "r11", "memory");
return ret;
}
@@ -29,8 +31,10 @@ int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
{
long ret;
- asm("syscall" : "=a" (ret) :
- "0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
+ asm("syscall"
+ : "=a" (ret)
+ : "0" (__NR_gettimeofday), "D" (tv), "S" (tz)
+ : "rcx", "r11", "memory");
return ret;
}