parisc: Avoid trashing sr2 and sr3 in LWS code
There is no need to trash sr2 and sr3 in the Light-weight syscall (LWS). sr2
already points to kernel space (it's zero in userspace, otherwise syscalls
wouldn't work), and since the LWS code is executed in userspace, we can simply
ignore to preload sr3.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S
index d03422e..40190db 100644
--- a/arch/parisc/kernel/syscall.S
+++ b/arch/parisc/kernel/syscall.S
@@ -474,11 +474,6 @@
comiclr,>> __NR_lws_entries, %r20, %r0
b,n lws_exit_nosys
- /* WARNING: Trashing sr2 and sr3 */
- mfsp %sr7,%r1 /* get userspace into sr3 */
- mtsp %r1,%sr3
- mtsp %r0,%sr2 /* get kernel space into sr2 */
-
/* Load table start */
ldil L%lws_table, %r1
ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */
@@ -627,9 +622,9 @@
stw %r1, 4(%sr2,%r20)
#endif
/* The load and store could fail */
-1: ldw,ma 0(%sr3,%r26), %r28
+1: ldw,ma 0(%r26), %r28
sub,<> %r28, %r25, %r0
-2: stw,ma %r24, 0(%sr3,%r26)
+2: stw,ma %r24, 0(%r26)
/* Free lock */
stw,ma %r20, 0(%sr2,%r20)
#if ENABLE_LWS_DEBUG
@@ -706,9 +701,9 @@
nop
/* 8bit load */
-4: ldb 0(%sr3,%r25), %r25
+4: ldb 0(%r25), %r25
b cas2_lock_start
-5: ldb 0(%sr3,%r24), %r24
+5: ldb 0(%r24), %r24
nop
nop
nop
@@ -716,9 +711,9 @@
nop
/* 16bit load */
-6: ldh 0(%sr3,%r25), %r25
+6: ldh 0(%r25), %r25
b cas2_lock_start
-7: ldh 0(%sr3,%r24), %r24
+7: ldh 0(%r24), %r24
nop
nop
nop
@@ -726,9 +721,9 @@
nop
/* 32bit load */
-8: ldw 0(%sr3,%r25), %r25
+8: ldw 0(%r25), %r25
b cas2_lock_start
-9: ldw 0(%sr3,%r24), %r24
+9: ldw 0(%r24), %r24
nop
nop
nop
@@ -737,14 +732,14 @@
/* 64bit load */
#ifdef CONFIG_64BIT
-10: ldd 0(%sr3,%r25), %r25
-11: ldd 0(%sr3,%r24), %r24
+10: ldd 0(%r25), %r25
+11: ldd 0(%r24), %r24
#else
/* Load new value into r22/r23 - high/low */
-10: ldw 0(%sr3,%r25), %r22
-11: ldw 4(%sr3,%r25), %r23
+10: ldw 0(%r25), %r22
+11: ldw 4(%r25), %r23
/* Load new value into fr4 for atomic store later */
-12: flddx 0(%sr3,%r24), %fr4
+12: flddx 0(%r24), %fr4
#endif
cas2_lock_start:
@@ -794,30 +789,30 @@
ldo 1(%r0),%r28
/* 8bit CAS */
-13: ldb,ma 0(%sr3,%r26), %r29
+13: ldb,ma 0(%r26), %r29
sub,= %r29, %r25, %r0
b,n cas2_end
-14: stb,ma %r24, 0(%sr3,%r26)
+14: stb,ma %r24, 0(%r26)
b cas2_end
copy %r0, %r28
nop
nop
/* 16bit CAS */
-15: ldh,ma 0(%sr3,%r26), %r29
+15: ldh,ma 0(%r26), %r29
sub,= %r29, %r25, %r0
b,n cas2_end
-16: sth,ma %r24, 0(%sr3,%r26)
+16: sth,ma %r24, 0(%r26)
b cas2_end
copy %r0, %r28
nop
nop
/* 32bit CAS */
-17: ldw,ma 0(%sr3,%r26), %r29
+17: ldw,ma 0(%r26), %r29
sub,= %r29, %r25, %r0
b,n cas2_end
-18: stw,ma %r24, 0(%sr3,%r26)
+18: stw,ma %r24, 0(%r26)
b cas2_end
copy %r0, %r28
nop
@@ -825,22 +820,22 @@
/* 64bit CAS */
#ifdef CONFIG_64BIT
-19: ldd,ma 0(%sr3,%r26), %r29
+19: ldd,ma 0(%r26), %r29
sub,*= %r29, %r25, %r0
b,n cas2_end
-20: std,ma %r24, 0(%sr3,%r26)
+20: std,ma %r24, 0(%r26)
copy %r0, %r28
#else
/* Compare first word */
-19: ldw,ma 0(%sr3,%r26), %r29
+19: ldw,ma 0(%r26), %r29
sub,= %r29, %r22, %r0
b,n cas2_end
/* Compare second word */
-20: ldw,ma 4(%sr3,%r26), %r29
+20: ldw,ma 4(%r26), %r29
sub,= %r29, %r23, %r0
b,n cas2_end
/* Perform the store */
-21: fstdx %fr4, 0(%sr3,%r26)
+21: fstdx %fr4, 0(%r26)
copy %r0, %r28
#endif