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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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4
arch/sparc/include/asm/ptrace.h
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@ -202,9 +202,7 @@ struct global_reg_snapshot {
};
extern struct global_reg_snapshot global_reg_snapshot[NR_CPUS];
#define force_successful_syscall_return() \
do { current_thread_info()->syscall_noerror = 1; \
} while (0)
#define force_successful_syscall_return() set_thread_noerror(1)
#define user_mode(regs) (!((regs)->tstate & TSTATE_PRIV))
#define instruction_pointer(regs) ((regs)->tpc)
#define instruction_pointer_set(regs, val) ((regs)->tpc = (val))

16
arch/sparc/include/asm/thread_info_64.h
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@ -18,10 +18,12 @@
#define TI_FLAG_CWP_SHIFT 40
#define TI_FLAG_BYTE_CURRENT_DS 3
#define TI_FLAG_CURRENT_DS_SHIFT 32
#define TI_FLAG_BYTE_FPDEPTH 4
#define TI_FLAG_FPDEPTH_SHIFT 24
#define TI_FLAG_BYTE_WSAVED 5
#define TI_FLAG_WSAVED_SHIFT 16
#define TI_FLAG_BYTE_NOERROR 4
#define TI_FLAG_BYTE_NOERROR_SHIFT 24
#define TI_FLAG_BYTE_FPDEPTH 5
#define TI_FLAG_FPDEPTH_SHIFT 16
#define TI_FLAG_BYTE_WSAVED 6
#define TI_FLAG_WSAVED_SHIFT 8
#include <asm/page.h>
@ -47,7 +49,7 @@ struct thread_info {
struct exec_domain *exec_domain;
int preempt_count; /* 0 => preemptable, <0 => BUG */
__u8 new_child;
__u8 syscall_noerror;
__u8 __pad;
__u16 cpu;
unsigned long *utraps;
@ -77,6 +79,7 @@ struct thread_info {
#define TI_CURRENT_DS (TI_FLAGS + TI_FLAG_BYTE_CURRENT_DS)
#define TI_FPDEPTH (TI_FLAGS + TI_FLAG_BYTE_FPDEPTH)
#define TI_WSAVED (TI_FLAGS + TI_FLAG_BYTE_WSAVED)
#define TI_SYS_NOERROR (TI_FLAGS + TI_FLAG_BYTE_NOERROR)
#define TI_FPSAVED 0x00000010
#define TI_KSP 0x00000018
#define TI_FAULT_ADDR 0x00000020
@ -84,7 +87,6 @@ struct thread_info {
#define TI_EXEC_DOMAIN 0x00000030
#define TI_PRE_COUNT 0x00000038
#define TI_NEW_CHILD 0x0000003c
#define TI_SYS_NOERROR 0x0000003d
#define TI_CPU 0x0000003e
#define TI_UTRAPS 0x00000040
#define TI_REG_WINDOW 0x00000048
@ -155,6 +157,8 @@ register struct thread_info *current_thread_info_reg asm("g6");
#define set_thread_cwp(val) (__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_CWP] = (val))
#define get_thread_current_ds() (__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_CURRENT_DS])
#define set_thread_current_ds(val) (__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_CURRENT_DS] = (val))
#define get_thread_noerror() (__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_NOERROR])
#define set_thread_noerror(val) (__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_NOERROR] = (val))
#define get_thread_fpdepth() (__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_FPDEPTH])
#define set_thread_fpdepth(val) (__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_FPDEPTH] = (val))
#define get_thread_wsaved() (__cur_thread_flag_byte_ptr[TI_FLAG_BYTE_WSAVED])

8
arch/sparc/kernel/etrap_64.S
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@ -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
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@ -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
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@ -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,