linux/arch/tile/include/asm/stack.h
Chris Metcalf 47ad7b9bbe tile: improve stack backtrace
This commit fixes a number of issues with the tile backtrace code.

- Don't try to identify userspace shared object or executable paths
  if we are doing a backtrace from an interrupt; it's not legal,
  and also unlikely to be interesting.  Likewise, don't try to do
  it for other address spaces, since d_path() assumes it is being
  called in "current" context.

- Move "in_backtrace" from thread_struct to thread_info.
  This way we can access it even if our stack thread_info has been
  clobbered, which makes backtracing more robust.

- Avoid using "current" directly when testing for is_sigreturn().
  Since "current" may be corrupt, we're better off using kbt->task
  explicitly to look up the vdso_base for the current task.
  Conveniently, this simplifies the internal APIs (we only need
  one is_sigreturn() function now).

- Avoid bogus "Odd fault" warning when pc/sp/ex1 are all zero,
  as is true for kernel threads above the last frame.

- Hook into Tejun Heo's dump_stack() framework in lib/dump_stack.c.

- Write last entry in save_stack_trace() as ULONG_MAX, not zero,
  since ftrace (at least) relies on finding that marker.

- Implement save_stack_trace_regs() and save_strack_trace_user(),
  and set CONFIG_USER_STACKTRACE_SUPPORT.

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
2015-05-11 11:22:40 -04:00

72 lines
2.6 KiB
C

/*
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#ifndef _ASM_TILE_STACK_H
#define _ASM_TILE_STACK_H
#include <linux/types.h>
#include <linux/sched.h>
#include <asm/backtrace.h>
#include <asm/page.h>
#include <hv/hypervisor.h>
/* Everything we need to keep track of a backtrace iteration */
struct KBacktraceIterator {
BacktraceIterator it;
struct task_struct *task; /* task we are backtracing */
int end; /* iteration complete. */
int new_context; /* new context is starting */
int profile; /* profiling, so stop on async intrpt */
int verbose; /* printk extra info (don't want to
* do this for profiling) */
int is_current; /* backtracing current task */
};
/* Iteration methods for kernel backtraces */
/*
* Initialize a KBacktraceIterator from a task_struct, and optionally from
* a set of registers. If the registers are omitted, the process is
* assumed to be descheduled, and registers are read from the process's
* thread_struct and stack. "verbose" means to printk some additional
* information about fault handlers as we pass them on the stack.
*/
extern void KBacktraceIterator_init(struct KBacktraceIterator *kbt,
struct task_struct *, struct pt_regs *);
/* Initialize iterator based on current stack. */
extern void KBacktraceIterator_init_current(struct KBacktraceIterator *kbt);
/* Helper method for above. */
extern void _KBacktraceIterator_init_current(struct KBacktraceIterator *kbt,
ulong pc, ulong lr, ulong sp, ulong r52);
/* No more frames? */
extern int KBacktraceIterator_end(struct KBacktraceIterator *kbt);
/* Advance to the next frame. */
extern void KBacktraceIterator_next(struct KBacktraceIterator *kbt);
/* Dump just the contents of the pt_regs structure. */
extern void tile_show_regs(struct pt_regs *);
/*
* Dump stack given complete register info. Use only from the
* architecture-specific code; show_stack()
* and dump_stack() are architecture-independent entry points.
*/
extern void tile_show_stack(struct KBacktraceIterator *);
#endif /* _ASM_TILE_STACK_H */