[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>
diff --git a/arch/sparc64/kernel/entry.S b/arch/sparc64/kernel/entry.S
index d781f10..88332f0 100644
--- a/arch/sparc64/kernel/entry.S
+++ b/arch/sparc64/kernel/entry.S
@@ -1600,11 +1600,11 @@
ba,pt %xcc, sparc_do_fork
add %sp, PTREGS_OFF, %o2
ret_from_syscall:
- /* Clear SPARC_FLAG_NEWCHILD, switch_to leaves thread.flags in
- * %o7 for us. Check performance counter stuff too.
+ /* Clear current_thread_info()->new_child, and
+ * check performance counter stuff too.
*/
- andn %o7, _TIF_NEWCHILD, %l0
- stx %l0, [%g6 + TI_FLAGS]
+ stb %g0, [%g6 + TI_NEW_CHILD]
+ ldx [%g6 + TI_FLAGS], %l0
call schedule_tail
mov %g7, %o0
andcc %l0, _TIF_PERFCTR, %g0
@@ -1720,12 +1720,11 @@
/* Check if force_successful_syscall_return()
* was invoked.
*/
- ldx [%curptr + TI_FLAGS], %l0
- andcc %l0, _TIF_SYSCALL_SUCCESS, %g0
- be,pt %icc, 1f
- andn %l0, _TIF_SYSCALL_SUCCESS, %l0
+ ldub [%curptr + TI_SYS_NOERROR], %l0
+ brz,pt %l0, 1f
+ nop
ba,pt %xcc, 80f
- stx %l0, [%curptr + TI_FLAGS]
+ stb %g0, [%curptr + TI_SYS_NOERROR]
1:
cmp %o0, -ERESTART_RESTARTBLOCK
diff --git a/arch/sparc64/kernel/process.c b/arch/sparc64/kernel/process.c
index a0cd2b2..cffb1c8 100644
--- a/arch/sparc64/kernel/process.c
+++ b/arch/sparc64/kernel/process.c
@@ -621,8 +621,8 @@
memcpy(child_trap_frame, (((struct sparc_stackf *)regs)-1), (TRACEREG_SZ+STACKFRAME_SZ));
t->flags = (t->flags & ~((0xffUL << TI_FLAG_CWP_SHIFT) | (0xffUL << TI_FLAG_CURRENT_DS_SHIFT))) |
- _TIF_NEWCHILD |
(((regs->tstate + 1) & TSTATE_CWP) << TI_FLAG_CWP_SHIFT);
+ t->new_child = 1;
t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
t->kregs = (struct pt_regs *)(child_trap_frame+sizeof(struct sparc_stackf));
t->fpsaved[0] = 0;
diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c
index 7e8e291..b9b4249 100644
--- a/arch/sparc64/kernel/smp.c
+++ b/arch/sparc64/kernel/smp.c
@@ -137,7 +137,7 @@
/* Clear this or we will die instantly when we
* schedule back to this idler...
*/
- clear_thread_flag(TIF_NEWCHILD);
+ current_thread_info()->new_child = 0;
/* Attach to the address space of init_task. */
atomic_inc(&init_mm.mm_count);
diff --git a/arch/sparc64/kernel/traps.c b/arch/sparc64/kernel/traps.c
index a9f4596..100b010 100644
--- a/arch/sparc64/kernel/traps.c
+++ b/arch/sparc64/kernel/traps.c
@@ -2125,6 +2125,8 @@
TI_PCR != offsetof(struct thread_info, pcr_reg) ||
TI_CEE_STUFF != offsetof(struct thread_info, cee_stuff) ||
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_FPREGS != offsetof(struct thread_info, fpregs) ||
(TI_FPREGS & (64 - 1)))
thread_info_offsets_are_bolixed_dave();
diff --git a/include/asm-sparc64/ptrace.h b/include/asm-sparc64/ptrace.h
index 2d2b5a1..6194f77 100644
--- a/include/asm-sparc64/ptrace.h
+++ b/include/asm-sparc64/ptrace.h
@@ -94,8 +94,9 @@
#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 f9be2c5..ee4bdfc 100644
--- a/include/asm-sparc64/system.h
+++ b/include/asm-sparc64/system.h
@@ -190,24 +190,23 @@
"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 a1d25c0..352d994 100644
--- a/include/asm-sparc64/thread_info.h
+++ b/include/asm-sparc64/thread_info.h
@@ -47,7 +47,9 @@
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 @@
#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 @@
#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 @@
#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)