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Commit 47ad7b9b authored by Chris Metcalf's avatar Chris Metcalf
Browse files

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: default avatarChris Metcalf <cmetcalf@ezchip.com>
parent e8200baa

arch/tile/Kconfig

+1 −0
Original line number Original line Diff line number Diff line
@@ -24,6 +24,7 @@ config TILE 
	select MODULES_USE_ELF_RELA

	select MODULES_USE_ELF_RELA

	select HAVE_ARCH_TRACEHOOK

	select HAVE_ARCH_TRACEHOOK

	select HAVE_SYSCALL_TRACEPOINTS

	select HAVE_SYSCALL_TRACEPOINTS

	select USER_STACKTRACE_SUPPORT

	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE

	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE

	select HAVE_DEBUG_STACKOVERFLOW

	select HAVE_DEBUG_STACKOVERFLOW

	select ARCH_WANT_FRAME_POINTERS

	select ARCH_WANT_FRAME_POINTERS

arch/tile/include/asm/processor.h

+0 −2
Original line number Original line Diff line number Diff line
@@ -111,8 +111,6 @@ struct thread_struct { 
	unsigned long long interrupt_mask;

	unsigned long long interrupt_mask;

	/* User interrupt-control 0 state */

	/* User interrupt-control 0 state */

	unsigned long intctrl_0;

	unsigned long intctrl_0;

	/* Is this task currently doing a backtrace? */

	bool in_backtrace;

	/* Any other miscellaneous processor state bits */

	/* Any other miscellaneous processor state bits */

	unsigned long proc_status;

	unsigned long proc_status;

#if !CHIP_HAS_FIXED_INTVEC_BASE()

#if !CHIP_HAS_FIXED_INTVEC_BASE()

arch/tile/include/asm/stack.h

+5 −8
Original line number Original line Diff line number Diff line
@@ -58,17 +58,14 @@ extern int KBacktraceIterator_end(struct KBacktraceIterator *kbt); 
/* Advance to the next frame. */

/* Advance to the next frame. */

extern void KBacktraceIterator_next(struct KBacktraceIterator *kbt);

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

 * Dump stack given complete register info. Use only from the

 * architecture-specific code; show_stack()

 * architecture-specific code; show_stack()

 * and dump_stack() (in entry.S) are architecture-independent entry points.

 * and dump_stack() are architecture-independent entry points.

 */

 */

extern void tile_show_stack(struct KBacktraceIterator *, int headers);

extern void tile_show_stack(struct KBacktraceIterator *);



/* Dump stack of current process, with registers to seed the backtrace. */

extern void dump_stack_regs(struct pt_regs *);



/* Helper method for assembly dump_stack(). */

extern void _dump_stack(int dummy, ulong pc, ulong lr, ulong sp, ulong r52);





#endif /* _ASM_TILE_STACK_H */
 
#endif /* _ASM_TILE_STACK_H */

arch/tile/include/asm/thread_info.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -42,6 +42,7 @@ struct thread_info { 
	unsigned long		unalign_jit_tmp[4]; /* temp r0..r3 storage */

	unsigned long		unalign_jit_tmp[4]; /* temp r0..r3 storage */

	void __user		*unalign_jit_base; /* unalign fixup JIT base */

	void __user		*unalign_jit_base; /* unalign fixup JIT base */

#endif

#endif

	bool in_backtrace;			/* currently doing backtrace? */

};

};





/*

/*

arch/tile/kernel/entry.S

+0 −7
Original line number Original line Diff line number Diff line
@@ -27,13 +27,6 @@ STD_ENTRY(current_text_addr) 
	{ move r0, lr; jrp lr }

	{ move r0, lr; jrp lr }

	STD_ENDPROC(current_text_addr)

	STD_ENDPROC(current_text_addr)





STD_ENTRY(dump_stack)

	{ move r2, lr; lnk r1 }

	{ move r4, r52; addli r1, r1, dump_stack - . }

	{ move r3, sp; j _dump_stack }

	jrp lr   /* keep backtracer happy */

	STD_ENDPROC(dump_stack)



STD_ENTRY(KBacktraceIterator_init_current)

STD_ENTRY(KBacktraceIterator_init_current)

	{ move r2, lr; lnk r1 }

	{ move r2, lr; lnk r1 }

	{ move r4, r52; addli r1, r1, KBacktraceIterator_init_current - . }

	{ move r4, r52; addli r1, r1, KBacktraceIterator_init_current - . }