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

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>

diff --git a/arch/sparc/include/asm/ptrace.h b/arch/sparc/include/asm/ptrace.h
index fd9c3f21cbf059d8130fd90d44cf67c3d0641942..eeed804316bfa02535b0dab0fe423387a6daa5d7 100644 (file)
--- a/arch/sparc/include/asm/ptrace.h
+++ b/arch/sparc/include/asm/ptrace.h
@@ -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))

diff --git a/arch/sparc/include/asm/thread_info_64.h b/arch/sparc/include/asm/thread_info_64.h
index cfa8c38fb9c8511d51cfbe17e3d8792584d8b241..8511e5fcc97dca630a56a7ed2376989227bf6102 100644 (file)
--- a/arch/sparc/include/asm/thread_info_64.h
+++ b/arch/sparc/include/asm/thread_info_64.h
@@ -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])

diff --git a/arch/sparc/kernel/etrap_64.S b/arch/sparc/kernel/etrap_64.S
index 786b185e6e3fa8d37e6cac8b820b0654b1b787c3..1276ca2567bab310771d214baa77876ea9e43f0e 100644 (file)
--- a/arch/sparc/kernel/etrap_64.S
+++ b/arch/sparc/kernel/etrap_64.S
@@ -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

diff --git a/arch/sparc/kernel/syscalls.S b/arch/sparc/kernel/syscalls.S
index 1d7e274f3f2b42bfac80354f1745c7ad48cd9e27..ed277e2fdfc838d42604457728128846190ed7be 100644 (file)
--- a/arch/sparc/kernel/syscalls.S
+++ b/arch/sparc/kernel/syscalls.S
@@ -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

diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index fa1f1d375ffc263571ab3b75e4dd0477284d583b..82af591fe43f8f0625babb98cea6b19c24ed53ef 100644 (file)
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -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,