2015-08-28 13:50:28

by Alexander Kuleshov

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Subject: [PATCH] [s390]: Use .rept directive to store/load fpu registers

We can use .rept directive to simplify/decrease assembly code
that makes storing and loading floating point registers in the
arch/s390/kernel/swsusp.S.

The resulting code after the patch is the same that before

2c4: 68 00 d2 00 ld %f0,512(%r13)
2c8: 68 10 d2 08 ld %f1,520(%r13)
2cc: 68 20 d2 10 ld %f2,528(%r13)
2d0: 68 30 d2 18 ld %f3,536(%r13)
2d4: 68 40 d2 20 ld %f4,544(%r13)
2d8: 68 50 d2 28 ld %f5,552(%r13)
2dc: 68 60 d2 30 ld %f6,560(%r13)
2e0: 68 70 d2 38 ld %f7,568(%r13)
2e4: 68 80 d2 40 ld %f8,576(%r13)
2e8: 68 90 d2 48 ld %f9,584(%r13)
2ec: 68 a0 d2 50 ld %f10,592(%r13)
2f0: 68 b0 d2 58 ld %f11,600(%r13)
2f4: 68 c0 d2 60 ld %f12,608(%r13)
2f8: 68 d0 d2 68 ld %f13,616(%r13)
2fc: 68 e0 d2 70 ld %f14,624(%r13)
300: 68 f0 d2 78 ld %f15,632(%r13)

Signed-off-by: Alexander Kuleshov <[email protected]>
---
arch/s390/kernel/swsusp.S | 49 ++++++++++++++++-------------------------------
1 file changed, 17 insertions(+), 32 deletions(-)

diff --git a/arch/s390/kernel/swsusp.S b/arch/s390/kernel/swsusp.S
index ca62946..8011e14 100644
--- a/arch/s390/kernel/swsusp.S
+++ b/arch/s390/kernel/swsusp.S
@@ -48,22 +48,15 @@ ENTRY(swsusp_arch_suspend)
/* Store registers */
mvc 0x318(4,%r1),__SF_EMPTY(%r15) /* move prefix to lowcore */
stfpc 0x31c(%r1) /* store fpu control */
- std 0,0x200(%r1) /* store f0 */
- std 1,0x208(%r1) /* store f1 */
- std 2,0x210(%r1) /* store f2 */
- std 3,0x218(%r1) /* store f3 */
- std 4,0x220(%r1) /* store f4 */
- std 5,0x228(%r1) /* store f5 */
- std 6,0x230(%r1) /* store f6 */
- std 7,0x238(%r1) /* store f7 */
- std 8,0x240(%r1) /* store f8 */
- std 9,0x248(%r1) /* store f9 */
- std 10,0x250(%r1) /* store f10 */
- std 11,0x258(%r1) /* store f11 */
- std 12,0x260(%r1) /* store f12 */
- std 13,0x268(%r1) /* store f13 */
- std 14,0x270(%r1) /* store f14 */
- std 15,0x278(%r1) /* store f15 */
+
+ /* store f0..f15 floating point registers */
+ .set i, 0
+ .set f, 0x200
+ .rept 16
+ std i, f(%r1)
+ .set i, (i+1)
+ .set f, (f+0x8)
+ .endr
stam %a0,%a15,0x340(%r1) /* store access registers */
stctg %c0,%c15,0x380(%r1) /* store control registers */
stmg %r0,%r15,0x280(%r1) /* store general registers */
@@ -250,22 +243,14 @@ restore_registers:
lam %a0,%a15,0x340(%r13) /* load access registers */

lfpc 0x31c(%r13) /* load fpu control */
- ld 0,0x200(%r13) /* load f0 */
- ld 1,0x208(%r13) /* load f1 */
- ld 2,0x210(%r13) /* load f2 */
- ld 3,0x218(%r13) /* load f3 */
- ld 4,0x220(%r13) /* load f4 */
- ld 5,0x228(%r13) /* load f5 */
- ld 6,0x230(%r13) /* load f6 */
- ld 7,0x238(%r13) /* load f7 */
- ld 8,0x240(%r13) /* load f8 */
- ld 9,0x248(%r13) /* load f9 */
- ld 10,0x250(%r13) /* load f10 */
- ld 11,0x258(%r13) /* load f11 */
- ld 12,0x260(%r13) /* load f12 */
- ld 13,0x268(%r13) /* load f13 */
- ld 14,0x270(%r13) /* load f14 */
- ld 15,0x278(%r13) /* load f15 */
+ /* load f0...f15 floating point registers */
+ .set i, 0
+ .set f, 0x200
+ .rept 16
+ ld i, f(%r13)
+ .set i, (i+1)
+ .set f, (f+0x8)
+ .endr

/* Load old stack */
lg %r15,0x2f8(%r13)
--
2.5.0