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

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

* for-next/stacktrace:
  arm64: remove EL0 exception frame record
This commit is contained in:
Will Deacon 2021-02-12 15:14:22 +00:00
commit d23fa87cde
2 changed files with 9 additions and 14 deletions
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10
arch/arm64/kernel/entry.S
View File

@ -261,16 +261,16 @@ alternative_else_nop_endif
stp lr, x21, [sp, #S_LR] stp lr, x21, [sp, #S_LR]
/* /*
* In order to be able to dump the contents of struct pt_regs at the * For exceptions from EL0, terminate the callchain here.
* time the exception was taken (in case we attempt to walk the call * For exceptions from EL1, create a synthetic frame record so the
* stack later), chain it together with the stack frames. * interrupted code shows up in the backtrace.
*/ */
.if \el == 0 .if \el == 0
stp xzr, xzr, [sp, #S_STACKFRAME] mov x29, xzr
.else .else
stp x29, x22, [sp, #S_STACKFRAME] stp x29, x22, [sp, #S_STACKFRAME]
.endif
add x29, sp, #S_STACKFRAME add x29, sp, #S_STACKFRAME
.endif
#ifdef CONFIG_ARM64_SW_TTBR0_PAN #ifdef CONFIG_ARM64_SW_TTBR0_PAN
alternative_if_not ARM64_HAS_PAN alternative_if_not ARM64_HAS_PAN

13
arch/arm64/kernel/stacktrace.c
View File

@ -44,6 +44,10 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
unsigned long fp = frame->fp; unsigned long fp = frame->fp;
struct stack_info info; struct stack_info info;
/* Terminal record; nothing to unwind */
if (!fp)
return -EINVAL;
if (fp & 0xf) if (fp & 0xf)
return -EINVAL; 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); 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; return 0;
} }
NOKPROBE_SYMBOL(unwind_frame); NOKPROBE_SYMBOL(unwind_frame);