[PATCH 4.4 36/37] sparc64: Dont clibber fixed registers in __multi4.

Greg Kroah-Hartman
2018-06-05T17:04:29Z

From: David S. Miller <davem@davemloft.net>

commit 79db795833bf5c3e798bcd7a5aeeee3fb0505927 upstream.

%g4 and %g5 are fixed registers used by the kernel for the thread
pointer and the per-cpu offset. Use %o4 and %g7 instead.

Diagnosis by Anthony Yznaga.

Fixes: 1b4af13ff2cc ("sparc64: Add __multi3 for gcc 7.x and later.")
Reported-by: Anatoly Pugachev <matorola@gmail.com>
Tested-by: Anatoly Pugachev <matorola@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/sparc/lib/multi3.S | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)

--- a/arch/sparc/lib/multi3.S
+++ b/arch/sparc/lib/multi3.S
@@ -5,26 +5,26 @@
.align 4
ENTRY(__multi3) /* %o0 = u, %o1 = v */
mov %o1, %g1
- srl %o3, 0, %g4
- mulx %g4, %g1, %o1
+ srl %o3, 0, %o4
+ mulx %o4, %g1, %o1
srlx %g1, 0x20, %g3
- mulx %g3, %g4, %g5
- sllx %g5, 0x20, %o5
- srl %g1, 0, %g4
+ mulx %g3, %o4, %g7
+ sllx %g7, 0x20, %o5
+ srl %g1, 0, %o4
sub %o1, %o5, %o5
srlx %o5, 0x20, %o5
- addcc %g5, %o5, %g5
+ addcc %g7, %o5, %g7
srlx %o3, 0x20, %o5
- mulx %g4, %o5, %g4
+ mulx %o4, %o5, %o4
mulx %g3, %o5, %o5
sethi %hi(0x80000000), %g3
- addcc %g5, %g4, %g5
- srlx %g5, 0x20, %g5
+ addcc %g7, %o4, %g7
+ srlx %g7, 0x20, %g7
add %g3, %g3, %g3
movcc %xcc, %g0, %g3
- addcc %o5, %g5, %o5
- sllx %g4, 0x20, %g4
- add %o1, %g4, %o1
+ addcc %o5, %g7, %o5
+ sllx %o4, 0x20, %o4
+ add %o1, %o4, %o1
add %o5, %g3, %g2
mulx %g1, %o2, %g1
add %g1, %g2, %g1