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Subject[PATCH 4.9 23/87] s390: remove indirect branch from do_softirq_own_stack
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

commit 9f18fff63cfd6f559daa1eaae60640372c65f84b upstream.

The inline assembly to call __do_softirq on the irq stack uses
an indirect branch. This can be replaced with a normal relative
branch.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/s390/kernel/irq.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

--- a/arch/s390/kernel/irq.c
+++ b/arch/s390/kernel/irq.c
@@ -173,10 +173,9 @@ void do_softirq_own_stack(void)
new -= STACK_FRAME_OVERHEAD;
((struct stack_frame *) new)->back_chain = old;
asm volatile(" la 15,0(%0)\n"
- " basr 14,%2\n"
+ " brasl 14,__do_softirq\n"
" la 15,0(%1)\n"
- : : "a" (new), "a" (old),
- "a" (__do_softirq)
+ : : "a" (new), "a" (old)
: "0", "1", "2", "3", "4", "5", "14",
"cc", "memory" );
} else {

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