Signed-off-by: Vineet Gupta <vgu...@synopsys.com>
---
arch/arc/kernel/unwind.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/arch/arc/kernel/unwind.c b/arch/arc/kernel/unwind.c
index b1a520afcbcb..6eb377c102c6 100644
--- a/arch/arc/kernel/unwind.c
+++ b/arch/arc/kernel/unwind.c
@@ -149,7 +149,7 @@ struct unwind_state {
uleb128_t reg, offs;
} cfa;
struct unwind_item regs[ARRAY_SIZE(reg_info)];
- unsigned stackDepth;
+ unsigned stackDepth:8, has_cfa_register:8;
const u8 *label;
const u8 *stack[MAX_STACK_DEPTH];
};
@@ -697,6 +697,7 @@ static int processCFI(const u8 *start, const u8 *end,
unsigned long targetLoc,
case DW_CFA_register:
str = "cfa_register: ";
value = get_uleb128(&ptr.p8, end);
+ state->has_cfa_register = 1;
set_rule(value, Register, get_uleb128(&ptr.p8,
end), state, str);
break;
case DW_CFA_remember_state:
@@ -1010,11 +1011,18 @@ int arc_unwind(struct unwind_frame_info *frame)
unw_debug("\nCFA reg: r%ld, off: %ld => [SP] 0x%lx\n",
state.cfa.reg, state.cfa.offs, cfa);
- for (i = 0; i < ARRAY_SIZE(state.regs); ++i) {
- switch (state.regs[i].where) {
- default:
- break;
- case Register:
+ /*
+ * For DW_CFA_register instruction, save registers initial state
+ * Note that a seperate pass is needed (vs. doing this in main loop
below)
+ * to capture state of those regs at time of entry into function since
+ * the main loop below can possibly clobber them due to CFA ops of
+ * function being processed
+ *
+ * Since ARC gcc doesn't seem to generate those (ABI thing ?) try to
+ * optimize out the loop
+ */
+ for (i = 0; state.has_cfa_register && i < ARRAY_SIZE(state.regs); ++i) {
+ if (state.regs[i].where == Register) {
if (state.regs[i].value >= ARRAY_SIZE(reg_info))
return -EIO;
switch (reg_info[state.regs[i].value].width) {
@@ -1039,7 +1047,6 @@ int arc_unwind(struct unwind_frame_info *frame)
default:
return -EIO;
}
- break;
}
}
--
1.9.1
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