[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();