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EABI unwinder enhancements... When it's time to stop unwinding, don't

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exit the loop until after printing info about the current frame.  Also,
if executing the unwind function for a frame doesn't change the values of
any registers, log that and exit the loop rather than looping endlessly.
This commit is contained in:
Ian Lepore 2013-05-04 19:50:50 +00:00
parent 5df1b6b57e
commit abf29ad1a4
1 changed files with 39 additions and 26 deletions
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65
sys/arm/arm/db_trace.c
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@ -342,8 +342,11 @@ db_stack_trace_cmd(struct unwind_state *state)
c_db_sym_t sym;
u_int reg, i;
char *sep;
uint16_t upd_mask;
bool finished;
while (1) {
finished = false;
while (!finished) {
/* Reset the mask of updated registers */
state->update_mask = 0;
@ -353,28 +356,20 @@ db_stack_trace_cmd(struct unwind_state *state)
/* Find the item to run */
index = db_find_index(state->start_pc);
if (index->insn == EXIDX_CANTUNWIND) {
db_printf("Unable to unwind\n");
break;
} else if (index->insn & (1 << 31)) {
/* The data is within the instruction */
state->insn = &index->insn;
} else {
/* We have a prel31 offset to the unwind table */
uint32_t prel31_tbl = db_expand_prel31(index->insn);
state->insn = (uint32_t *)((uintptr_t)&index->insn +
prel31_tbl);
if (index->insn != EXIDX_CANTUNWIND) {
if (index->insn & (1 << 31)) {
/* The data is within the instruction */
state->insn = &index->insn;
} else {
/* A prel31 offset to the unwind table */
state->insn = (uint32_t *)
((uintptr_t)&index->insn +
db_expand_prel31(index->insn));
}
/* Run the unwind function */
finished = db_unwind_tab(state);
}
/* Run the unwind function */
if (db_unwind_tab(state) != 0)
break;
/* This is not a kernel address, stop processing */
if (state->registers[PC] < VM_MIN_KERNEL_ADDRESS)
break;
/* Print the frame details */
sym = db_search_symbol(state->start_pc, DB_STGY_ANY, &offset);
if (sym == C_DB_SYM_NULL) {
@ -393,12 +388,11 @@ db_stack_trace_cmd(struct unwind_state *state)
state->registers[SP], state->registers[FP]);
/* Don't print the registers we have already printed */
state->update_mask &= ~((1 << SP) | (1 << FP) | (1 << LR) |
(1 << PC));
upd_mask = state->update_mask &
~((1 << SP) | (1 << FP) | (1 << LR) | (1 << PC));
sep = "\n\t";
for (i = 0, reg = 0; state->update_mask != 0;
state->update_mask >>= 1, reg++) {
if ((state->update_mask & 1) != 0) {
for (i = 0, reg = 0; upd_mask != 0; upd_mask >>= 1, reg++) {
if ((upd_mask & 1) != 0) {
db_printf("%s%sr%d = 0x%08x", sep,
(reg < 10) ? " " : "", reg,
state->registers[reg]);
@ -412,6 +406,25 @@ db_stack_trace_cmd(struct unwind_state *state)
}
}
db_printf("\n");
/* Stop if directed to do so, or if we've unwound back to the
* kernel entry point, or if the unwind function didn't change
* anything (to avoid getting stuck in this loop forever).
* If the latter happens, it's an indication that the unwind
* information is incorrect somehow for the function named in
* the last frame printed before you see the unwind failure
* message (maybe it needs a STOP_UNWINDING).
*/
if (index->insn == EXIDX_CANTUNWIND) {
db_printf("Unable to unwind further\n");
finished = true;
} else if (state->registers[PC] < VM_MIN_KERNEL_ADDRESS) {
db_printf("Unable to unwind into user mode\n");
finished = true;
} else if (state->update_mask == 0) {
db_printf("Unwind failure (no registers changed)\n");
finished = true;
}
}
}
#endif