4.9-stable review patch. If anyone has any objections, please let me know.
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From: Christian Borntraeger borntraeger@de.ibm.com
commit 891f6a726cacbb87e5b06076693ffab53bd378d7 upstream.
In the critical section cleanup we must not mess with r1. For march=z9 or older, larl + ex (instead of exrl) are used with r1 as a temporary register. This can clobber r1 in several interrupt handlers. Fix this by using r11 as a temp register. r11 is being saved by all callers of cleanup_critical.
Fixes: 6dd85fbb87 ("s390: move expoline assembler macros to a header") Cc: stable@vger.kernel.org #v4.16 Reported-by: Oliver Kurz okurz@suse.com Reported-by: Petr Tesařík ptesarik@suse.com Signed-off-by: Christian Borntraeger borntraeger@de.ibm.com Reviewed-by: Hendrik Brueckner brueckner@linux.ibm.com Signed-off-by: Martin Schwidefsky schwidefsky@de.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/s390/kernel/entry.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -1187,7 +1187,7 @@ cleanup_critical: jl 0f clg %r9,BASED(.Lcleanup_table+104) # .Lload_fpu_regs_end jl .Lcleanup_load_fpu_regs -0: BR_EX %r14 +0: BR_EX %r14,%r11
.align 8 .Lcleanup_table: @@ -1217,7 +1217,7 @@ cleanup_critical: ni __SIE_PROG0C+3(%r9),0xfe # no longer in SIE lctlg %c1,%c1,__LC_USER_ASCE # load primary asce larl %r9,sie_exit # skip forward to sie_exit - BR_EX %r14 + BR_EX %r14,%r11 #endif
.Lcleanup_system_call: