From a051bc5bb1ac6dc138d529077fa20cbbc6622d95 Mon Sep 17 00:00:00 2001 From: "David S. Miller" <davem@davemloft.net> Date: Wed, 21 May 2008 18:14:28 -0700 Subject: sparc64: Fix kernel thread stack termination. Because of the silly way I set up the initial stack for new kernel threads, there is a loop at the top of the stack. To fix this, properly add another stack frame that is copied from the parent and terminate it in the child by setting the frame pointer in that frame to zero. Signed-off-by: David S. Miller <davem@davemloft.net> --- arch/sparc64/kernel/process.c | 36 +++++++++++++++++++++++++----------- 1 file changed, 25 insertions(+), 11 deletions(-) (limited to 'arch') 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 { -- cgit v1.2.3-58-ga151 From 14d2c68baa659cfd15dc782dd229ea304330c4f6 Mon Sep 17 00:00:00 2001 From: "David S. Miller" <davem@davemloft.net> Date: Wed, 21 May 2008 18:15:53 -0700 Subject: sparc64: Fix stack tracing through trap frames. The offset to the pt_regs area was wrong, so we weren't looking at the right location for the magic cookie. A trap frame is composed of a "struct sparc_stackf" then a "struct pt_regs", the code was using "struct reg_window" instead of "struct sparc_stackf". Signed-off-by: David S. Miller <davem@davemloft.net> --- arch/sparc64/kernel/stacktrace.c | 12 +++++++----- arch/sparc64/kernel/traps.c | 12 +++++++----- 2 files changed, 14 insertions(+), 10 deletions(-) (limited to 'arch') 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); -- cgit v1.2.3-58-ga151 From ada44a0430fdd00b3f38aad0aa518e97cb760bd0 Mon Sep 17 00:00:00 2001 From: "David S. Miller" <davem@davemloft.net> Date: Wed, 21 May 2008 21:50:01 -0700 Subject: sparc64: Prevent stack backtrace false positives on trap frames. When we fully commit to returning back to kernel mode from a trap, zero out the regs->magic value to prevent false positives during stack backtraces. Signed-off-by: David S. Miller <davem@davemloft.net> --- arch/sparc64/kernel/rtrap.S | 1 + 1 file changed, 1 insertion(+) (limited to 'arch') 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 -- cgit v1.2.3-58-ga151