From f4125cfdb3008363137f744c101e5d76ead760ba Mon Sep 17 00:00:00 2001 From: John David Anglin Date: Fri, 28 Oct 2016 22:13:42 +0200 Subject: 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 Signed-off-by: Helge Deller --- arch/parisc/kernel/syscall.S | 53 ++++++++++++++++++++------------------------ 1 file changed, 24 insertions(+), 29 deletions(-) (limited to 'arch/parisc') diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S index d03422e5f188..40190dbecdc0 100644 --- a/arch/parisc/kernel/syscall.S +++ b/arch/parisc/kernel/syscall.S @@ -474,11 +474,6 @@ lws_start: 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 @@ cas_action: 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 @@ lws_compare_and_swap_2: 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 @@ lws_compare_and_swap_2: 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 @@ lws_compare_and_swap_2: 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 @@ lws_compare_and_swap_2: /* 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 @@ cas2_action: 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 @@ cas2_action: /* 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 -- cgit v1.2.3