Commit d23fa87c authored by Will Deacon's avatar Will Deacon
Browse files

Merge branch 'for-next/stacktrace' into for-next/core 

Remove synthetic frame record from exception stack when entering from
userspace.

* for-next/stacktrace:
  arm64: remove EL0 exception frame record
parents 82a1c2b9 6106e111

arch/arm64/kernel/entry.S

+5 −5
Original line number Diff line number Diff line
@@ -261,16 +261,16 @@ alternative_else_nop_endif 
	stp	lr, x21, [sp, #S_LR]



	/*

	 * In order to be able to dump the contents of struct pt_regs at the

	 * time the exception was taken (in case we attempt to walk the call

	 * stack later), chain it together with the stack frames.

	 * For exceptions from EL0, terminate the callchain here.

	 * For exceptions from EL1, create a synthetic frame record so the

	 * interrupted code shows up in the backtrace.

	 */

	.if \el == 0

	stp	xzr, xzr, [sp, #S_STACKFRAME]

	mov	x29, xzr

	.else

	stp	x29, x22, [sp, #S_STACKFRAME]

	.endif

	add	x29, sp, #S_STACKFRAME

	.endif



#ifdef CONFIG_ARM64_SW_TTBR0_PAN

alternative_if_not ARM64_HAS_PAN

arch/arm64/kernel/stacktrace.c

+4 −9
Original line number Diff line number Diff line
@@ -44,6 +44,10 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame) 
	unsigned long fp = frame->fp;

	struct stack_info info;



	/* Terminal record; nothing to unwind */

	if (!fp)

		return -EINVAL;



	if (fp & 0xf)

		return -EINVAL;
@@ -104,15 +108,6 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame) 


	frame->pc = ptrauth_strip_insn_pac(frame->pc);



	/*

	 * Frames created upon entry from EL0 have NULL FP and PC values, so

	 * don't bother reporting these. Frames created by __noreturn functions

	 * might have a valid FP even if PC is bogus, so only terminate where

	 * both are NULL.

	 */

	if (!frame->fp && !frame->pc)

		return -EINVAL;



	return 0;

}

NOKPROBE_SYMBOL(unwind_frame);