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sparc64: Rearrange thread info to cheaply clear syscall noerror state.

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After fixing a couple of brainos, it even seems to work.  What's done here
is move of ->syscall_noerror right before FPDEPTH byte in ->flags and
using sth to [%g6 + TI_SYS_NOERROR] instead of stb to [%g6 + TI_FPDEPTH] in
both branches of etrap_save.  AFAICS, that ought to be solid.  Again,
deciding what to do with now unused delay slot of branch on ->syscall_noerror
and dealing with the order of tests in ret_from_sys is a separate question,
but at least that way we don't have to clean ->syscall_noerror in there at
all.  AFAICS, it ought to be a clear win - sth is not going to cost more than
stb on etrap_64.S side of things, and we are losing write on syscalls.S one.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Al Viro
2012-10-04 13:52:53 -07:00
committed by David S. Miller
parent ecefbd94b8
commit 40138249c3
5 changed files with 19 additions and 15 deletions
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8
arch/sparc/kernel/etrap_64.S
View File

@@ -92,8 +92,10 @@ etrap_save: save %g2, -STACK_BIAS, %sp
rdpr %wstate, %g2
wrpr %g0, 0, %canrestore
sll %g2, 3, %g2
/* Set TI_SYS_FPDEPTH to 1 and clear TI_SYS_NOERROR. */
mov 1, %l5
stb %l5, [%l6 + TI_FPDEPTH]
sth %l5, [%l6 + TI_SYS_NOERROR]
wrpr %g3, 0, %otherwin
wrpr %g2, 0, %wstate
@@ -152,7 +154,9 @@ etrap_save: save %g2, -STACK_BIAS, %sp
add %l6, TI_FPSAVED + 1, %l4
srl %l5, 1, %l3
add %l5, 2, %l5
stb %l5, [%l6 + TI_FPDEPTH]
/* Set TI_SYS_FPDEPTH to %l5 and clear TI_SYS_NOERROR. */
sth %l5, [%l6 + TI_SYS_NOERROR]
ba,pt %xcc, 2b
stb %g0, [%l4 + %l3]
nop

4
arch/sparc/kernel/syscalls.S
View File

@@ -221,8 +221,8 @@ ret_sys_call:
* was invoked.
*/
ldub [%g6 + TI_SYS_NOERROR], %l2
brnz,a,pn %l2, 80f
stb %g0, [%g6 + TI_SYS_NOERROR]
brnz,pn %l2, 80f
nop
cmp %o0, -ERESTART_RESTARTBLOCK
bgeu,pn %xcc, 1f

2
arch/sparc/kernel/traps_64.c
View File

@@ -2547,8 +2547,6 @@ void __init trap_init(void)
TI_PRE_COUNT != offsetof(struct thread_info,
preempt_count) ||
TI_NEW_CHILD != offsetof(struct thread_info, new_child) ||
TI_SYS_NOERROR != offsetof(struct thread_info,
syscall_noerror) ||
TI_RESTART_BLOCK != offsetof(struct thread_info,
restart_block) ||
TI_KUNA_REGS != offsetof(struct thread_info,