[ 125/135] s390: fix system call restart after inferior call

From: Greg Kroah-Hartman
Date: Fri Oct 11 2013 - 15:49:14 EST


3.11-stable review patch. If anyone has any objections, please let me know.

------------------

From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>

commit dbbfe487e5f3fc00c9fe5207d63309859704d12f upstream.

Git commit 616498813b11ffef "s390: system call path micro optimization"
introduced a regression in regard to system call restarting and inferior
function calls via the ptrace interface. The pointer to the system call
table needs to be loaded in sysc_sigpending if do_signal returns with
TIF_SYSCALl set after it restored a system call context.

Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/s390/kernel/entry.S | 1 +
arch/s390/kernel/entry64.S | 1 +
2 files changed, 2 insertions(+)

--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -265,6 +265,7 @@ sysc_sigpending:
tm __TI_flags+3(%r12),_TIF_SYSCALL
jno sysc_return
lm %r2,%r7,__PT_R2(%r11) # load svc arguments
+ l %r10,__TI_sysc_table(%r12) # 31 bit system call table
xr %r8,%r8 # svc 0 returns -ENOSYS
clc __PT_INT_CODE+2(2,%r11),BASED(.Lnr_syscalls+2)
jnl sysc_nr_ok # invalid svc number -> do svc 0
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -296,6 +296,7 @@ sysc_sigpending:
tm __TI_flags+7(%r12),_TIF_SYSCALL
jno sysc_return
lmg %r2,%r7,__PT_R2(%r11) # load svc arguments
+ lg %r10,__TI_sysc_table(%r12) # address of system call table
lghi %r8,0 # svc 0 returns -ENOSYS
llgh %r1,__PT_INT_CODE+2(%r11) # load new svc number
cghi %r1,NR_syscalls


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