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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>
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f4125cfdb3
1 changed files with 24 additions and 29 deletions
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@ -474,11 +474,6 @@ lws_start:
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comiclr,>> __NR_lws_entries, %r20, %r0
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b,n lws_exit_nosys
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/* WARNING: Trashing sr2 and sr3 */
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mfsp %sr7,%r1 /* get userspace into sr3 */
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mtsp %r1,%sr3
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mtsp %r0,%sr2 /* get kernel space into sr2 */
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/* Load table start */
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ldil L%lws_table, %r1
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ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */
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@ -627,9 +622,9 @@ cas_action:
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stw %r1, 4(%sr2,%r20)
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#endif
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/* The load and store could fail */
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1: ldw,ma 0(%sr3,%r26), %r28
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1: ldw,ma 0(%r26), %r28
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sub,<> %r28, %r25, %r0
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2: stw,ma %r24, 0(%sr3,%r26)
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2: stw,ma %r24, 0(%r26)
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/* Free lock */
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stw,ma %r20, 0(%sr2,%r20)
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#if ENABLE_LWS_DEBUG
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@ -706,9 +701,9 @@ lws_compare_and_swap_2:
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nop
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/* 8bit load */
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4: ldb 0(%sr3,%r25), %r25
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4: ldb 0(%r25), %r25
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b cas2_lock_start
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5: ldb 0(%sr3,%r24), %r24
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5: ldb 0(%r24), %r24
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nop
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nop
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nop
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@ -716,9 +711,9 @@ lws_compare_and_swap_2:
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nop
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/* 16bit load */
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6: ldh 0(%sr3,%r25), %r25
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6: ldh 0(%r25), %r25
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b cas2_lock_start
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7: ldh 0(%sr3,%r24), %r24
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7: ldh 0(%r24), %r24
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nop
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nop
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nop
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@ -726,9 +721,9 @@ lws_compare_and_swap_2:
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nop
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/* 32bit load */
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8: ldw 0(%sr3,%r25), %r25
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8: ldw 0(%r25), %r25
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b cas2_lock_start
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9: ldw 0(%sr3,%r24), %r24
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9: ldw 0(%r24), %r24
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nop
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nop
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nop
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@ -737,14 +732,14 @@ lws_compare_and_swap_2:
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/* 64bit load */
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#ifdef CONFIG_64BIT
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10: ldd 0(%sr3,%r25), %r25
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11: ldd 0(%sr3,%r24), %r24
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10: ldd 0(%r25), %r25
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11: ldd 0(%r24), %r24
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#else
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/* Load new value into r22/r23 - high/low */
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10: ldw 0(%sr3,%r25), %r22
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11: ldw 4(%sr3,%r25), %r23
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10: ldw 0(%r25), %r22
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11: ldw 4(%r25), %r23
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/* Load new value into fr4 for atomic store later */
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12: flddx 0(%sr3,%r24), %fr4
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12: flddx 0(%r24), %fr4
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#endif
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cas2_lock_start:
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@ -794,30 +789,30 @@ cas2_action:
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ldo 1(%r0),%r28
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/* 8bit CAS */
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13: ldb,ma 0(%sr3,%r26), %r29
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13: ldb,ma 0(%r26), %r29
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sub,= %r29, %r25, %r0
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b,n cas2_end
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14: stb,ma %r24, 0(%sr3,%r26)
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14: stb,ma %r24, 0(%r26)
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b cas2_end
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copy %r0, %r28
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nop
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nop
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/* 16bit CAS */
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15: ldh,ma 0(%sr3,%r26), %r29
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15: ldh,ma 0(%r26), %r29
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sub,= %r29, %r25, %r0
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b,n cas2_end
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16: sth,ma %r24, 0(%sr3,%r26)
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16: sth,ma %r24, 0(%r26)
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b cas2_end
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copy %r0, %r28
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nop
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nop
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/* 32bit CAS */
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17: ldw,ma 0(%sr3,%r26), %r29
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17: ldw,ma 0(%r26), %r29
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sub,= %r29, %r25, %r0
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b,n cas2_end
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18: stw,ma %r24, 0(%sr3,%r26)
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18: stw,ma %r24, 0(%r26)
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b cas2_end
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copy %r0, %r28
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nop
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@ -825,22 +820,22 @@ cas2_action:
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/* 64bit CAS */
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#ifdef CONFIG_64BIT
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19: ldd,ma 0(%sr3,%r26), %r29
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19: ldd,ma 0(%r26), %r29
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sub,*= %r29, %r25, %r0
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b,n cas2_end
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20: std,ma %r24, 0(%sr3,%r26)
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20: std,ma %r24, 0(%r26)
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copy %r0, %r28
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#else
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/* Compare first word */
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19: ldw,ma 0(%sr3,%r26), %r29
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19: ldw,ma 0(%r26), %r29
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sub,= %r29, %r22, %r0
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b,n cas2_end
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/* Compare second word */
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20: ldw,ma 4(%sr3,%r26), %r29
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20: ldw,ma 4(%r26), %r29
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sub,= %r29, %r23, %r0
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b,n cas2_end
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/* Perform the store */
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21: fstdx %fr4, 0(%sr3,%r26)
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21: fstdx %fr4, 0(%r26)
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copy %r0, %r28
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#endif
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