diff options
| author | Vasily Gorbik <gor@linux.ibm.com> | 2026-03-26 19:50:14 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-04-02 13:25:38 +0200 |
| commit | 99a8b420f3f0e162eb9c9c9253929d4d23f9bd30 (patch) | |
| tree | fb9d74751e9f9ec80fa3aba6a53bff79c90c2864 /arch | |
| parent | a047370045e419dc5ec344b0ec99df6b475ca7ca (diff) | |
s390/entry: Scrub r12 register on kernel entry
commit 0738d395aab8fae3b5a3ad3fc640630c91693c27 upstream.
Before commit f33f2d4c7c80 ("s390/bp: remove TIF_ISOLATE_BP"),
all entry handlers loaded r12 with the current task pointer
(lg %r12,__LC_CURRENT) for use by the BPENTER/BPEXIT macros. That
commit removed TIF_ISOLATE_BP, dropping both the branch prediction
macros and the r12 load, but did not add r12 to the register clearing
sequence.
Add the missing xgr %r12,%r12 to make the register scrub consistent
across all entry points.
Fixes: f33f2d4c7c80 ("s390/bp: remove TIF_ISOLATE_BP")
Cc: stable@kernel.org
Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/s390/kernel/entry.S | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index b7f1553d9ee5..fc385e99f1f8 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -260,6 +260,7 @@ SYM_CODE_START(system_call) xgr %r9,%r9 xgr %r10,%r10 xgr %r11,%r11 + xgr %r12,%r12 la %r2,STACK_FRAME_OVERHEAD(%r15) # pointer to pt_regs mvc __PT_R8(64,%r2),__LC_SAVE_AREA(%r13) MBEAR %r2,%r13 @@ -396,6 +397,7 @@ SYM_CODE_START(\name) xgr %r6,%r6 xgr %r7,%r7 xgr %r10,%r10 + xgr %r12,%r12 xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11) mvc __PT_R8(64,%r11),__LC_SAVE_AREA(%r13) MBEAR %r11,%r13 @@ -485,6 +487,7 @@ SYM_CODE_START(mcck_int_handler) xgr %r6,%r6 xgr %r7,%r7 xgr %r10,%r10 + xgr %r12,%r12 stmg %r8,%r9,__PT_PSW(%r11) xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11) xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15) |