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powerpc: copy_thread fill in interrupt frame marker and back chain

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Backtraces will not recognise the fork system call interrupt without
the regs marker. And regular interrupt entry from userspace creates
the back chain to the user stack, so do this for the initial fork
frame too, to be consistent.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221127124942.1665522-13-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2022-11-27 22:49:37 +10:00 committed by Michael Ellerman
parent 6f291a0381
commit 6895dfc047
1 changed files with 3 additions and 1 deletions
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4
arch/powerpc/kernel/process.c
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@ -1757,12 +1757,13 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
/* Create initial stack frame. */
sp -= STACK_USER_INT_FRAME_SIZE;
((unsigned long *)sp)[0] = 0;
*(unsigned long *)(sp + STACK_INT_FRAME_MARKER) = STACK_FRAME_REGS_MARKER;
/* Copy registers */
childregs = (struct pt_regs *)(sp + STACK_INT_FRAME_REGS);
if (unlikely(args->fn)) {
/* kernel thread */
((unsigned long *)sp)[0] = 0;
memset(childregs, 0, sizeof(struct pt_regs));
childregs->gpr[1] = sp + STACK_USER_INT_FRAME_SIZE;
/* function */
@ -1782,6 +1783,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
*childregs = *regs;
if (usp)
childregs->gpr[1] = usp;
((unsigned long *)sp)[0] = childregs->gpr[1];
p->thread.regs = childregs;
/* 64s sets this in ret_from_fork */
if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64))