mirror of
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arch/risc-v: fix up_backtrace() bugs and rework stack splicing
Bugs fixed: 1. BUILD_FLAT/BUILD_PROTECTED: the interrupt-context self backtrace printed the same frames twice. 2. BUILD_KERNEL: a cross-tcb backtrace never included the target task's kernel stack, so frames on it were missing. Also reworked the implementation around a list of independent starting points, each carrying every stack range its fp chain may cross into, splicing them into one backtrace. Assisted-by: Claude Code:claude-sonnet-5 Signed-off-by: liang.huang <liang.huang@houmo.ai>
This commit is contained in:
liang.huang
Alan C. Assis
parent
ed368470d1
commit
57c7e47a6b
1 changed files with 324 additions and 108 deletions
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@ -25,11 +25,85 @@
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdbool.h>
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#include <nuttx/arch.h>
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#include <nuttx/addrenv.h>
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#include <nuttx/compiler.h>
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#include "sched/sched.h"
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#include "riscv_internal.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Maximum number of independent starting points up_backtrace() can splice
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* together. Current worst case: the main fp chain (possibly starting on
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* the interrupt or kernel stack) plus the xcp.sregs splice used to reach
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* the user call site of a task that is mid-syscall.
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*/
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#define BACKTRACE_MAX_SEGMENTS 2
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/* Upper bound on how many candidate ranges a single segment can
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* register: interrupt stack, kernel stack, user stack.
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*/
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#define BACKTRACE_MAX_RANGES 3
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/****************************************************************************
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* Private Types
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****************************************************************************/
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/* One candidate stack range a segment's fp chain may be walking. */
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struct backtrace_range_s
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{
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uintptr_t *base;
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uintptr_t *limit;
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#ifdef CONFIG_ARCH_ADDRENV
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struct addrenv_s *addrenv;
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#endif
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};
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/* One independent fp/ra starting point for backtrace_segments() to walk,
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* together with every stack range its chain may legitimately be found on.
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*/
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struct backtrace_segment_s
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{
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uintptr_t *fp;
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uintptr_t *ra;
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struct backtrace_range_s ranges[BACKTRACE_MAX_RANGES];
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int nranges;
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static struct backtrace_segment_s *
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backtrace_new_segment(struct backtrace_segment_s *segments,
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int *nsegments, uintptr_t *fp, uintptr_t *ra);
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static void backtrace_add_range(struct backtrace_segment_s *segment,
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uintptr_t *base, uintptr_t *limit
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#ifdef CONFIG_ARCH_ADDRENV
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, struct addrenv_s *addrenv
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#endif
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);
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/* BACKTRACE_ADD_RANGE() drops the trailing addrenv argument when
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* CONFIG_ARCH_ADDRENV is not configured, so call sites never need their own
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* #ifdef.
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*/
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#ifdef CONFIG_ARCH_ADDRENV
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# define BACKTRACE_ADD_RANGE(segment, base, limit, addrenv) \
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backtrace_add_range(segment, base, limit, addrenv)
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#else
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# define BACKTRACE_ADD_RANGE(segment, base, limit, addrenv) \
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backtrace_add_range(segment, base, limit)
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#endif
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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@ -42,7 +116,7 @@
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*
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****************************************************************************/
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static inline uintptr_t getfp(void)
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static always_inline_function uintptr_t getfp(void)
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{
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register uintptr_t fp;
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@ -55,6 +129,61 @@ static inline uintptr_t getfp(void)
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return fp;
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}
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/****************************************************************************
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* Name: backtrace_add_range
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*
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* Description:
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* Append one candidate stack range to a segment.
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*
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****************************************************************************/
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static void backtrace_add_range(struct backtrace_segment_s *segment,
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uintptr_t *base, uintptr_t *limit
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#ifdef CONFIG_ARCH_ADDRENV
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, struct addrenv_s *addrenv
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#endif
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)
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{
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struct backtrace_range_s *range;
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DEBUGASSERT(segment->nranges < BACKTRACE_MAX_RANGES);
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range = &segment->ranges[segment->nranges++];
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range->base = base;
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range->limit = limit;
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#ifdef CONFIG_ARCH_ADDRENV
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range->addrenv = addrenv;
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#endif
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}
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/****************************************************************************
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* Name: backtrace_new_segment
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*
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* Description:
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* Allocate the next free segment slot and initialize its fp/ra starting
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* point.
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*
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* Returned Value:
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* A pointer to the newly allocated segment, ready for BACKTRACE_ADD_RANGE()
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* calls.
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*
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****************************************************************************/
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static struct backtrace_segment_s *
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backtrace_new_segment(struct backtrace_segment_s *segments,
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int *nsegments, uintptr_t *fp, uintptr_t *ra)
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{
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struct backtrace_segment_s *segment;
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segment = &segments[(*nsegments)++];
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segment->fp = fp;
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segment->ra = ra;
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segment->nranges = 0;
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return segment;
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}
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/****************************************************************************
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* Name: backtrace
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*
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@ -63,30 +192,24 @@ static inline uintptr_t getfp(void)
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*
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****************************************************************************/
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nosanitize_address
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nosanitize_address noinline_function
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static int backtrace(uintptr_t *base, uintptr_t *limit,
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uintptr_t *fp, uintptr_t *ra,
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void **buffer, int size, int *skip
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void **buffer, int size, int *skip,
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uintptr_t **bridge
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#ifdef CONFIG_ARCH_ADDRENV
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, FAR struct addrenv_s *addrenv
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, struct addrenv_s *addrenv
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#endif
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)
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{
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int i = 0;
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uintptr_t *next_fp;
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#if CONFIG_ARCH_INTERRUPTSTACK > 15
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int cpu = up_cpu_index();
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uintptr_t *intstack_limit =
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(uintptr_t *)((uintptr_t)g_intstacktop -
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(CONFIG_ARCH_INTERRUPTSTACK * cpu));
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uintptr_t *intstack_base =
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(uintptr_t *)((uintptr_t)intstack_limit - CONFIG_ARCH_INTERRUPTSTACK);
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#endif
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#ifdef CONFIG_ARCH_ADDRENV
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FAR struct addrenv_s *oldenv;
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struct addrenv_s *oldenv;
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#endif
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*bridge = NULL;
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if (ra)
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{
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if ((*skip)-- <= 0)
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@ -95,18 +218,19 @@ static int backtrace(uintptr_t *base, uintptr_t *limit,
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}
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}
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for (; i < size; fp = next_fp)
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for (; i < size && fp != NULL; fp = next_fp)
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{
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if ((fp > limit || fp < base)
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#if CONFIG_ARCH_INTERRUPTSTACK > 15
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&& (fp > intstack_limit || fp < intstack_base)
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#endif
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)
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if (fp > limit || fp < base)
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{
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/* fp is outside [base, limit]. Report it back through
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* *bridge and stop; the caller decides what to do with it.
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*/
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*bridge = fp;
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break;
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}
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/* fp/fp-1/fp-2 are addresses in the *target* tcb's stack. If that
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/* fp-1/fp-2 are addresses in the *target* tcb's stack. If that
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* tcb has its own address environment, switch to it only for these
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* two dereferences. buffer belongs to the caller, not the target,
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* and must always be written using the caller's own address
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@ -144,6 +268,89 @@ static int backtrace(uintptr_t *base, uintptr_t *limit,
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return i;
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}
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/****************************************************************************
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* Name: backtrace_walk_segment
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*
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* Description:
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* Walk one segment's fp chain, switching to the next candidate range
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* whenever backtrace() bridges out of the one it was given. Ranges are
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* only ever crossed outward (e.g. interrupt stack -> kernel stack -> user
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* stack, never backwards), so the search for the next range picks up from
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* where the previous one left off instead of rescanning from the start.
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*
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****************************************************************************/
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static int backtrace_walk_segment(struct backtrace_segment_s *segment,
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void **buffer, int size, int *skip)
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{
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uintptr_t *fp = segment->fp;
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uintptr_t *ra = segment->ra;
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uintptr_t *bridge;
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int total = 0;
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int ir = 0;
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for (; ; )
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{
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for (; ir < segment->nranges; ir++)
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{
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if (fp <= segment->ranges[ir].limit &&
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fp >= segment->ranges[ir].base)
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{
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break;
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}
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}
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if (ir == segment->nranges)
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{
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break;
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}
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total += backtrace(segment->ranges[ir].base, segment->ranges[ir].limit,
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fp, ra, &buffer[total], size - total, skip,
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&bridge
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#ifdef CONFIG_ARCH_ADDRENV
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, segment->ranges[ir].addrenv
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#endif
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);
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if (bridge == NULL || total >= size)
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{
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break;
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}
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fp = bridge;
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ra = NULL;
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}
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return total;
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}
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/****************************************************************************
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* Name: backtrace_segments
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*
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* Description:
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* Walk a short list of stack segments in order, carrying over into the
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* next one whenever the current segment stops producing frames before
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* the buffer is full.
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*
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****************************************************************************/
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static int backtrace_segments(struct backtrace_segment_s *segments,
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int nsegments, void **buffer, int size,
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int *skip)
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{
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int ret = 0;
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int i;
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for (i = 0; i < nsegments && ret < size; i++)
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{
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ret += backtrace_walk_segment(&segments[i], &buffer[ret],
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size - ret, skip);
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}
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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@ -162,6 +369,12 @@ static int backtrace(uintptr_t *base, uintptr_t *limit,
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* recent function calls are returned; to obtain the complete backtrace,
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* make sure that buffer and size are large enough.
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*
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* A task that is (or was, at the last trap) mid-syscall has its call
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* chain split across two stacks: the kernel stack (from the trap that
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* entered the syscall up to the ecall itself) and, continuing from
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* there, the user stack (the application code that issued the ecall).
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* Both segments are walked and spliced together into one buffer.
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*
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* Input Parameters:
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* tcb - Address of the task's TCB
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* buffer - Return address from the corresponding stack frame
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@ -184,100 +397,103 @@ static int backtrace(uintptr_t *base, uintptr_t *limit,
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int up_backtrace(struct tcb_s *tcb, void **buffer, int size, int skip)
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{
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struct tcb_s *rtcb = running_task();
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int ret;
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struct backtrace_segment_s segments[BACKTRACE_MAX_SEGMENTS];
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struct backtrace_segment_s *segment;
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uintptr_t *ubase;
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uintptr_t *ulimit;
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bool self = (tcb == NULL || tcb == rtcb);
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int nsegments = 0;
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#if CONFIG_ARCH_INTERRUPTSTACK > 15
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int cpu;
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uintptr_t *ilimit;
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uintptr_t *ibase;
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#endif
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#ifdef CONFIG_LIB_SYSCALL
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bool insyscall;
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#endif
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if (size <= 0 || !buffer)
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{
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return 0;
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}
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if (tcb == NULL || tcb == rtcb)
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if (self)
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{
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if (up_interrupt_context())
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{
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ret = backtrace(rtcb->stack_base_ptr,
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(uintptr_t *)((uintptr_t)rtcb->stack_base_ptr +
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rtcb->adj_stack_size),
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(void *)getfp(), NULL, buffer, size, &skip
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#ifdef CONFIG_ARCH_ADDRENV
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, NULL
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#endif
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);
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if (ret < size)
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{
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ret += backtrace(rtcb->stack_base_ptr, (uintptr_t *)
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((uintptr_t)rtcb->stack_base_ptr +
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rtcb->adj_stack_size),
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running_regs()[REG_FP],
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running_regs()[REG_EPC],
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&buffer[ret], size - ret, &skip
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#ifdef CONFIG_ARCH_ADDRENV
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, NULL
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#endif
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);
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}
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}
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else
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{
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#ifdef CONFIG_ARCH_KERNEL_STACK
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if ((rtcb->flags & TCB_FLAG_SYSCALL) != 0)
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{
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ret = backtrace(rtcb->stack_base_ptr, (uintptr_t *)
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((uintptr_t)rtcb->stack_base_ptr +
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rtcb->adj_stack_size),
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(void *)rtcb->xcp.sregs[REG_FP],
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(void *)rtcb->xcp.sregs[REG_EPC],
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buffer, size, &skip
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#ifdef CONFIG_ARCH_ADDRENV
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, NULL
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#endif
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);
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}
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else
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#endif
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{
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ret = backtrace(rtcb->stack_base_ptr, (uintptr_t *)
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((uintptr_t)rtcb->stack_base_ptr +
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rtcb->adj_stack_size),
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(void *)getfp(), NULL, buffer, size, &skip
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#ifdef CONFIG_ARCH_ADDRENV
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, NULL
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#endif
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);
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}
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}
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}
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else
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{
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#ifdef CONFIG_ARCH_KERNEL_STACK
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if ((tcb->flags & TCB_FLAG_SYSCALL) != 0)
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{
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ret = backtrace(tcb->stack_base_ptr,
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(uintptr_t *)((uintptr_t)tcb->stack_base_ptr +
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tcb->adj_stack_size),
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(void *)tcb->xcp.sregs[REG_FP],
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(void *)tcb->xcp.sregs[REG_EPC],
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buffer, size, &skip
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#ifdef CONFIG_ARCH_ADDRENV
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, tcb->addrenv_own
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#endif
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);
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}
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else
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#endif
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{
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ret = backtrace(tcb->stack_base_ptr,
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(uintptr_t *)((uintptr_t)tcb->stack_base_ptr +
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tcb->adj_stack_size),
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(void *)tcb->xcp.regs[REG_FP],
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(void *)tcb->xcp.regs[REG_EPC],
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buffer, size, &skip
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#ifdef CONFIG_ARCH_ADDRENV
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, tcb->addrenv_own
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#endif
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);
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}
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tcb = rtcb;
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}
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return ret;
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ubase = tcb->stack_base_ptr;
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ulimit = (uintptr_t *)((uintptr_t)tcb->stack_base_ptr +
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tcb->adj_stack_size);
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#ifdef CONFIG_LIB_SYSCALL
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insyscall = (tcb->flags & TCB_FLAG_SYSCALL) != 0;
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#endif
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/* The main fp chain may start on (and naturally unwind through) any
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* stack the tcb was last executing on, innermost first: the interrupt
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* stack, then the kernel stack, then finally the user stack. Every
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* range it could legitimately cross into is listed up front instead of
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* picking just one ahead of time, since the trap entry copies the
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* pre-trap fp/ra into each synthetic frame, letting the chain unwind
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* straight through a trap boundary onto the next stack out.
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*/
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segment = backtrace_new_segment(segments, &nsegments,
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self ? (uintptr_t *)getfp() :
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(uintptr_t *)tcb->xcp.regs[REG_FP],
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self ? NULL :
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(uintptr_t *)tcb->xcp.regs[REG_EPC]);
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#if CONFIG_ARCH_INTERRUPTSTACK > 15
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if (self)
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{
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/* Only a self chain can genuinely start on the interrupt stack: it
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* is per-CPU scratch space, reused on every dispatch, so a snapshot
|
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* taken from a not-running tcb can never legitimately point into
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* it.
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*/
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cpu = up_cpu_index();
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ilimit = (uintptr_t *)((uintptr_t)g_intstacktop -
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(CONFIG_ARCH_INTERRUPTSTACK * cpu));
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ibase = (uintptr_t *)((uintptr_t)ilimit - CONFIG_ARCH_INTERRUPTSTACK);
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BACKTRACE_ADD_RANGE(segment, ibase, ilimit, NULL);
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}
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#endif
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#if defined(CONFIG_ARCH_KERNEL_STACK) && defined(CONFIG_ARCH_ADDRENV)
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if (tcb->xcp.kstack != NULL)
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{
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BACKTRACE_ADD_RANGE(segment, tcb->xcp.kstack,
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(uintptr_t *)((uintptr_t)tcb->xcp.kstack +
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ARCH_KERNEL_STACKSIZE), NULL);
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}
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#endif
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BACKTRACE_ADD_RANGE(segment, ubase, ulimit,
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self ? NULL : tcb->addrenv_own);
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#ifdef CONFIG_LIB_SYSCALL
|
||||
/* The main chain above stops at the nearest ecall boundary --
|
||||
* dispatch_syscall()'s own call frame has no relation to the user fp
|
||||
* chain, so there is nothing for it to unwind into. xcp.sregs is
|
||||
* stable (written once by dispatch_syscall(), never by reserved
|
||||
* syscalls) and gives the real user call site, so splice it in as an
|
||||
* independent starting point.
|
||||
*/
|
||||
|
||||
if (insyscall)
|
||||
{
|
||||
segment = backtrace_new_segment(segments, &nsegments,
|
||||
(uintptr_t *)tcb->xcp.sregs[REG_FP],
|
||||
(uintptr_t *)tcb->xcp.sregs[REG_EPC]);
|
||||
|
||||
BACKTRACE_ADD_RANGE(segment, ubase, ulimit,
|
||||
self ? NULL : tcb->addrenv_own);
|
||||
}
|
||||
#endif
|
||||
|
||||
return backtrace_segments(segments, nsegments, buffer, size, &skip);
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue