From a051bc5bb1ac6dc138d529077fa20cbbc6622d95 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Wed, 21 May 2008 18:14:28 -0700 Subject: [PATCH] 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 --- arch/sparc64/kernel/process.c | 36 ++++++++++++++++++++++++----------- 1 file changed, 25 insertions(+), 11 deletions(-) diff --git a/arch/sparc64/kernel/process.c b/arch/sparc64/kernel/process.c index 0a0c05fc3a3..2084f81a76e 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 { -- 2.20.1