github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-27 08:33:17 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

s390/entry: Scrub r12 register on kernel entry

Browse Source 
Before commit f33f2d4c7c ("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: f33f2d4c7c ("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>
This commit is contained in:
Vasily Gorbik 2026-03-26 19:50:14 +01:00
parent 48b8814e25
commit 0738d395aa
1 changed files with 3 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/s390/kernel/entry.S
View File

@ -271,6 +271,7 @@ 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
@ -407,6 +408,7 @@ 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
@ -496,6 +498,7 @@ 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)