Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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>
+24
-10
arch/sparc64/kernel/process.c
+24
-10
arch/sparc64/kernel/process.c
···
657
struct task_struct *p, struct pt_regs *regs)
658
{
659
struct thread_info *t = task_thread_info(p);
660
char *child_trap_frame;
661
662
/* Calculate offset to stack_frame & pt_regs */
663
-
child_trap_frame = task_stack_page(p) + (THREAD_SIZE - (TRACEREG_SZ+STACKFRAME_SZ));
664
-
memcpy(child_trap_frame, (((struct sparc_stackf *)regs)-1), (TRACEREG_SZ+STACKFRAME_SZ));
665
666
-
t->flags = (t->flags & ~((0xffUL << TI_FLAG_CWP_SHIFT) | (0xffUL << TI_FLAG_CURRENT_DS_SHIFT))) |
667
(((regs->tstate + 1) & TSTATE_CWP) << TI_FLAG_CWP_SHIFT);
668
t->new_child = 1;
669
t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
670
-
t->kregs = (struct pt_regs *)(child_trap_frame+sizeof(struct sparc_stackf));
671
t->fpsaved[0] = 0;
672
673
-
if (regs->tstate & TSTATE_PRIV) {
674
/* Special case, if we are spawning a kernel thread from
675
* a userspace task (via KMOD, NFS, or similar) we must
676
* disable performance counters in the child because the
···
700
t->pcr_reg = 0;
701
t->flags &= ~_TIF_PERFCTR;
702
}
703
-
t->kregs->u_regs[UREG_FP] = t->ksp;
704
t->flags |= ((long)ASI_P << TI_FLAG_CURRENT_DS_SHIFT);
705
-
flush_register_windows();
706
-
memcpy((void *)(t->ksp + STACK_BIAS),
707
-
(void *)(regs->u_regs[UREG_FP] + STACK_BIAS),
708
-
sizeof(struct sparc_stackf));
709
t->kregs->u_regs[UREG_G6] = (unsigned long) t;
710
t->kregs->u_regs[UREG_G4] = (unsigned long) t->task;
711
} else {
···
657
struct task_struct *p, struct pt_regs *regs)
658
{
659
struct thread_info *t = task_thread_info(p);
660
+
struct sparc_stackf *parent_sf;
661
+
unsigned long child_stack_sz;
662
char *child_trap_frame;
663
+
int kernel_thread;
664
+
665
+
kernel_thread = (regs->tstate & TSTATE_PRIV) ? 1 : 0;
666
+
parent_sf = ((struct sparc_stackf *) regs) - 1;
667
668
/* Calculate offset to stack_frame & pt_regs */
669
+
child_stack_sz = ((STACKFRAME_SZ + TRACEREG_SZ) +
670
+
(kernel_thread ? STACKFRAME_SZ : 0));
671
+
child_trap_frame = (task_stack_page(p) +
672
+
(THREAD_SIZE - child_stack_sz));
673
+
memcpy(child_trap_frame, parent_sf, child_stack_sz);
674
675
+
t->flags = (t->flags & ~((0xffUL << TI_FLAG_CWP_SHIFT) |
676
+
(0xffUL << TI_FLAG_CURRENT_DS_SHIFT))) |
677
(((regs->tstate + 1) & TSTATE_CWP) << TI_FLAG_CWP_SHIFT);
678
t->new_child = 1;
679
t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
680
+
t->kregs = (struct pt_regs *) (child_trap_frame +
681
+
sizeof(struct sparc_stackf));
682
t->fpsaved[0] = 0;
683
684
+
if (kernel_thread) {
685
+
struct sparc_stackf *child_sf = (struct sparc_stackf *)
686
+
(child_trap_frame + (STACKFRAME_SZ + TRACEREG_SZ));
687
+
688
+
/* Zero terminate the stack backtrace. */
689
+
child_sf->fp = NULL;
690
+
t->kregs->u_regs[UREG_FP] =
691
+
((unsigned long) child_sf) - STACK_BIAS;
692
+
693
/* Special case, if we are spawning a kernel thread from
694
* a userspace task (via KMOD, NFS, or similar) we must
695
* disable performance counters in the child because the
···
681
t->pcr_reg = 0;
682
t->flags &= ~_TIF_PERFCTR;
683
}
684
t->flags |= ((long)ASI_P << TI_FLAG_CURRENT_DS_SHIFT);
685
t->kregs->u_regs[UREG_G6] = (unsigned long) t;
686
t->kregs->u_regs[UREG_G4] = (unsigned long) t->task;
687
} else {