[SPARC64]: Move syscall success and newchild state out of thread flags.

These two bits were accesses non-atomically from assembler
code.  So, in order to eliminate any potential races resulting
from that, move these pieces of state into two bytes elsewhere
in struct thread_info.

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 15 insertions, 13 deletions

diff --git a/include/asm-sparc64/ptrace.h b/include/asm-sparc64/ptrace.h
index 2d2b5a113d24..6194f771e9fc 100644
--- a/include/asm-sparc64/ptrace.h
+++ b/include/asm-sparc64/ptrace.h
@@ -94,8 +94,9 @@ struct sparc_trapf {
 #define STACKFRAME32_SZ	sizeof(struct sparc_stackf32)
 
 #ifdef __KERNEL__
-#define force_successful_syscall_return()	\
-	set_thread_flag(TIF_SYSCALL_SUCCESS)
+#define force_successful_syscall_return()	    \
+do {	current_thread_info()->syscall_noerror = 1; \
+} while (0)
 #define user_mode(regs) (!((regs)->tstate & TSTATE_PRIV))
 #define instruction_pointer(regs) ((regs)->tpc)
 #ifdef CONFIG_SMP
diff --git a/include/asm-sparc64/system.h b/include/asm-sparc64/system.h
index f9be2c5b4dc9..ee4bdfc6b88f 100644
--- a/include/asm-sparc64/system.h
+++ b/include/asm-sparc64/system.h
@@ -190,24 +190,23 @@ do {	if (test_thread_flag(TIF_PERFCTR)) {				\
 	"wrpr	%%g1, %%cwp\n\t"					\
 	"ldx	[%%g6 + %3], %%o6\n\t"					\
 	"ldub	[%%g6 + %2], %%o5\n\t"					\
-	"ldx	[%%g6 + %4], %%o7\n\t"					\
+	"ldub	[%%g6 + %4], %%o7\n\t"					\
 	"mov	%%g6, %%l2\n\t"						\
 	"wrpr	%%o5, 0x0, %%wstate\n\t"				\
 	"ldx	[%%sp + 2047 + 0x70], %%i6\n\t"				\
 	"ldx	[%%sp + 2047 + 0x78], %%i7\n\t"				\
 	"wrpr	%%g0, 0x94, %%pstate\n\t"				\
 	"mov	%%l2, %%g6\n\t"						\
-	"ldx	[%%g6 + %7], %%g4\n\t"					\
+	"ldx	[%%g6 + %6], %%g4\n\t"					\
 	"wrpr	%%g0, 0x96, %%pstate\n\t"				\
-	"andcc	%%o7, %6, %%g0\n\t"					\
-	"beq,pt %%icc, 1f\n\t"						\
+	"brz,pt %%o7, 1f\n\t"						\
 	" mov	%%g7, %0\n\t"						\
 	"b,a ret_from_syscall\n\t"					\
 	"1:\n\t"							\
 	: "=&r" (last)							\
 	: "0" (next->thread_info),					\
-	  "i" (TI_WSTATE), "i" (TI_KSP), "i" (TI_FLAGS), "i" (TI_CWP),	\
-	  "i" (_TIF_NEWCHILD), "i" (TI_TASK)				\
+	  "i" (TI_WSTATE), "i" (TI_KSP), "i" (TI_NEW_CHILD),            \
+	  "i" (TI_CWP), "i" (TI_TASK)					\
 	: "cc",								\
 	        "g1", "g2", "g3",                   "g7",		\
 	              "l2", "l3", "l4", "l5", "l6", "l7",		\
diff --git a/include/asm-sparc64/thread_info.h b/include/asm-sparc64/thread_info.h
index a1d25c06f92a..352d9943661a 100644
--- a/include/asm-sparc64/thread_info.h
+++ b/include/asm-sparc64/thread_info.h
@@ -47,7 +47,9 @@ struct thread_info {
 	struct pt_regs		*kregs;
 	struct exec_domain	*exec_domain;
 	int			preempt_count;	/* 0 => preemptable, <0 => BUG */
-	int			__pad;
+	__u8			new_child;
+	__u8			syscall_noerror;
+	__u16			__pad;
 
 	unsigned long		*utraps;
 
@@ -87,6 +89,8 @@ struct thread_info {
 #define TI_KREGS	0x00000028
 #define TI_EXEC_DOMAIN	0x00000030
 #define TI_PRE_COUNT	0x00000038
+#define TI_NEW_CHILD	0x0000003c
+#define TI_SYS_NOERROR	0x0000003d
 #define TI_UTRAPS	0x00000040
 #define TI_REG_WINDOW	0x00000048
 #define TI_RWIN_SPTRS	0x000003c8	
@@ -219,10 +223,10 @@ register struct thread_info *current_thread_info_reg asm("g6");
 #define TIF_UNALIGNED		5	/* allowed to do unaligned accesses */
 #define TIF_NEWSIGNALS		6	/* wants new-style signals */
 #define TIF_32BIT		7	/* 32-bit binary */
-#define TIF_NEWCHILD		8	/* just-spawned child process */
+/* flag bit 8 is available */
 #define TIF_SECCOMP		9	/* secure computing */
 #define TIF_SYSCALL_AUDIT	10	/* syscall auditing active */
-#define TIF_SYSCALL_SUCCESS	11
+/* flag bit 11 is available */
 /* NOTE: Thread flags >= 12 should be ones we have no interest
  *       in using in assembly, else we can't use the mask as
  *       an immediate value in instructions such as andcc.
@@ -239,10 +243,8 @@ register struct thread_info *current_thread_info_reg asm("g6");
 #define _TIF_UNALIGNED		(1<<TIF_UNALIGNED)
 #define _TIF_NEWSIGNALS		(1<<TIF_NEWSIGNALS)
 #define _TIF_32BIT		(1<<TIF_32BIT)
-#define _TIF_NEWCHILD		(1<<TIF_NEWCHILD)
 #define _TIF_SECCOMP		(1<<TIF_SECCOMP)
 #define _TIF_SYSCALL_AUDIT	(1<<TIF_SYSCALL_AUDIT)
-#define _TIF_SYSCALL_SUCCESS	(1<<TIF_SYSCALL_SUCCESS)
 #define _TIF_ABI_PENDING	(1<<TIF_ABI_PENDING)
 #define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)