Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
  sparc64: Prevent stack backtrace false positives on trap frames.
  sparc64: Fix stack tracing through trap frames.
  sparc64: Fix kernel thread stack termination.
  sunhv: Fix locking in non-paged I/O case.

4 files changed, 40 insertions, 21 deletions

diff --git a/arch/sparc64/kernel/process.c b/arch/sparc64/kernel/process.c
index 0a0c05fc3a33..2084f81a76e1 100644
--- a/arch/sparc64/kernel/process.c
+++ b/arch/sparc64/kernel/process.c
@@ -657,20 +657,39 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
                 struct task_struct *p, struct pt_regs *regs)
 {
         struct thread_info *t = task_thread_info(p);
+        struct sparc_stackf *parent_sf;
+        unsigned long child_stack_sz;
         char *child_trap_frame;
+        int kernel_thread;
 
-        /* Calculate offset to stack_frame & pt_regs */
-        child_trap_frame = task_stack_page(p) + (THREAD_SIZE - (TRACEREG_SZ+STACKFRAME_SZ));
-        memcpy(child_trap_frame, (((struct sparc_stackf *)regs)-1), (TRACEREG_SZ+STACKFRAME_SZ));
+        kernel_thread = (regs->tstate & TSTATE_PRIV) ? 1 : 0;
+        parent_sf = ((struct sparc_stackf *) regs) - 1;
 
-        t->flags = (t->flags & ~((0xffUL << TI_FLAG_CWP_SHIFT) | (0xffUL << TI_FLAG_CURRENT_DS_SHIFT))) |
+        /* Calculate offset to stack_frame & pt_regs */
+        child_stack_sz = ((STACKFRAME_SZ + TRACEREG_SZ) +
+                          (kernel_thread ? STACKFRAME_SZ : 0));
+        child_trap_frame = (task_stack_page(p) +
+                            (THREAD_SIZE - child_stack_sz));
+        memcpy(child_trap_frame, parent_sf, child_stack_sz);
+
+        t->flags = (t->flags & ~((0xffUL << TI_FLAG_CWP_SHIFT) |
+                                 (0xffUL << TI_FLAG_CURRENT_DS_SHIFT))) |
                 (((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->kregs = (struct pt_regs *) (child_trap_frame +
+                                       sizeof(struct sparc_stackf));
         t->fpsaved[0] = 0;
 
-        if (regs->tstate & TSTATE_PRIV) {
+        if (kernel_thread) {
+                struct sparc_stackf *child_sf = (struct sparc_stackf *)
+                        (child_trap_frame + (STACKFRAME_SZ + TRACEREG_SZ));
+
+                /* Zero terminate the stack backtrace.  */
+                child_sf->fp = NULL;
+                t->kregs->u_regs[UREG_FP] =
+                  ((unsigned long) child_sf) - STACK_BIAS;
+
                 /* Special case, if we are spawning a kernel thread from
                  * a userspace task (via KMOD, NFS, or similar) we must
                  * disable performance counters in the child because the
@@ -681,12 +700,7 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
                         t->pcr_reg = 0;
                         t->flags &= ~_TIF_PERFCTR;
                 }
-                t->kregs->u_regs[UREG_FP] = t->ksp;
                 t->flags |= ((long)ASI_P << TI_FLAG_CURRENT_DS_SHIFT);
-                flush_register_windows();
-                memcpy((void *)(t->ksp + STACK_BIAS),
-                       (void *)(regs->u_regs[UREG_FP] + STACK_BIAS),
-                       sizeof(struct sparc_stackf));
                 t->kregs->u_regs[UREG_G6] = (unsigned long) t;
                 t->kregs->u_regs[UREG_G4] = (unsigned long) t->task;
         } else {
diff --git a/arch/sparc64/kernel/rtrap.S b/arch/sparc64/kernel/rtrap.S
index 3afacbb5781d..c6fc695fe1fe 100644
--- a/arch/sparc64/kernel/rtrap.S
+++ b/arch/sparc64/kernel/rtrap.S
@@ -363,6 +363,7 @@ kern_rtt:	rdpr			%canrestore, %g1
                 brz,pn                  %g1, kern_rtt_fill
                  nop
 kern_rtt_restore:
+                stw                     %g0, [%sp + PTREGS_OFF + PT_V9_MAGIC]
                 restore
                 retry
 
diff --git a/arch/sparc64/kernel/stacktrace.c b/arch/sparc64/kernel/stacktrace.c
index 01b52f561af4..c73ce3f4197e 100644
--- a/arch/sparc64/kernel/stacktrace.c
+++ b/arch/sparc64/kernel/stacktrace.c
@@ -19,7 +19,7 @@ void save_stack_trace(struct stack_trace *trace)
         fp = ksp + STACK_BIAS;
         thread_base = (unsigned long) tp;
         do {
-                struct reg_window *rw;
+                struct sparc_stackf *sf;
                 struct pt_regs *regs;
                 unsigned long pc;
 
@@ -28,15 +28,17 @@ void save_stack_trace(struct stack_trace *trace)
                     fp >= (thread_base + THREAD_SIZE))
                         break;
 
-                rw = (struct reg_window *) fp;
-                regs = (struct pt_regs *) (rw + 1);
+                sf = (struct sparc_stackf *) fp;
+                regs = (struct pt_regs *) (sf + 1);
 
                 if ((regs->magic & ~0x1ff) == PT_REGS_MAGIC) {
+                        if (!(regs->tstate & TSTATE_PRIV))
+                                break;
                         pc = regs->tpc;
                         fp = regs->u_regs[UREG_I6] + STACK_BIAS;
                 } else {
-                        pc = rw->ins[7];
-                        fp = rw->ins[6] + STACK_BIAS;
+                        pc = sf->callers_pc;
+                        fp = (unsigned long)sf->fp + STACK_BIAS;
                 }
 
                 if (trace->skip > 0)
diff --git a/arch/sparc64/kernel/traps.c b/arch/sparc64/kernel/traps.c
index d9b8d46707d1..369749262653 100644
--- a/arch/sparc64/kernel/traps.c
+++ b/arch/sparc64/kernel/traps.c
@@ -2116,7 +2116,7 @@ void show_stack(struct task_struct *tsk, unsigned long *_ksp)
         printk("\n");
 #endif
         do {
-                struct reg_window *rw;
+                struct sparc_stackf *sf;
                 struct pt_regs *regs;
                 unsigned long pc;
 
@@ -2124,15 +2124,17 @@ void show_stack(struct task_struct *tsk, unsigned long *_ksp)
                 if (fp < (thread_base + sizeof(struct thread_info)) ||
                     fp >= (thread_base + THREAD_SIZE))
                         break;
-                rw = (struct reg_window *)fp;
-                regs = (struct pt_regs *) (rw + 1);
+                sf = (struct sparc_stackf *) fp;
+                regs = (struct pt_regs *) (sf + 1);
 
                 if ((regs->magic & ~0x1ff) == PT_REGS_MAGIC) {
+                        if (!(regs->tstate & TSTATE_PRIV))
+                                break;
                         pc = regs->tpc;
                         fp = regs->u_regs[UREG_I6] + STACK_BIAS;
                 } else {
-                        pc = rw->ins[7];
-                        fp = rw->ins[6] + STACK_BIAS;
+                        pc = sf->callers_pc;
+                        fp = (unsigned long)sf->fp + STACK_BIAS;
                 }
 
                 printk(" [%016lx] ", pc);