Add a way to examine the unwind data without actually
restoring the data back into env.
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
include/exec/exec-all.h | 13 ++++++++
accel/tcg/translate-all.c | 68 ++++++++++++++++++++++++++-------------
2 files changed, 58 insertions(+), 23 deletions(-)
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 300832bd0b..d49cf113dd 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -39,6 +39,19 @@ typedef ram_addr_t tb_page_addr_t;
#define TB_PAGE_ADDR_FMT RAM_ADDR_FMT
#endif
+/**
+ * cpu_unwind_state_data:
+ * @cpu: the vCPU state is to be restore to
+ * @host_pc: the host PC the fault occurred at
+ * @data: output data
+ *
+ * Attempt to load the the unwind state for a host pc occurring in
+ * translated code. If the searched_pc is not in translated code,
+ * the function returns false; otherwise @data is loaded.
+ * This is the same unwind info as given to restore_state_to_opc.
+ */
+bool cpu_unwind_state_data(CPUState *cpu, uintptr_t host_pc, uint64_t *data);
+
/**
* cpu_restore_state:
* @cpu: the vCPU state is to be restore to
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index e4386b3198..c772e3769c 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -320,29 +320,20 @@ static int encode_search(TranslationBlock *tb, uint8_t
*block)
return p - block;
}
-/* The cpu state corresponding to 'searched_pc' is restored.
- * When reset_icount is true, current TB will be interrupted and
- * icount should be recalculated.
- */
-static int cpu_restore_state_from_tb(CPUState *cpu, TranslationBlock *tb,
- uintptr_t searched_pc, bool reset_icount)
+static int cpu_unwind_data_from_tb(TranslationBlock *tb, uintptr_t host_pc,
+ uint64_t *data)
{
- uint64_t data[TARGET_INSN_START_WORDS];
- uintptr_t host_pc = (uintptr_t)tb->tc.ptr;
+ uintptr_t iter_pc = (uintptr_t)tb->tc.ptr;
const uint8_t *p = tb->tc.ptr + tb->tc.size;
int i, j, num_insns = tb->icount;
-#ifdef CONFIG_PROFILER
- TCGProfile *prof = &tcg_ctx->prof;
- int64_t ti = profile_getclock();
-#endif
- searched_pc -= GETPC_ADJ;
+ host_pc -= GETPC_ADJ;
- if (searched_pc < host_pc) {
+ if (host_pc < iter_pc) {
return -1;
}
- memset(data, 0, sizeof(data));
+ memset(data, 0, sizeof(uint64_t) * TARGET_INSN_START_WORDS);
if (!TARGET_TB_PCREL) {
data[0] = tb_pc(tb);
}
@@ -353,19 +344,40 @@ static int cpu_restore_state_from_tb(CPUState *cpu,
TranslationBlock *tb,
for (j = 0; j < TARGET_INSN_START_WORDS; ++j) {
data[j] += decode_sleb128(&p);
}
- host_pc += decode_sleb128(&p);
- if (host_pc > searched_pc) {
- goto found;
+ iter_pc += decode_sleb128(&p);
+ if (iter_pc > host_pc) {
+ return num_insns - i;
}
}
return -1;
+}
+
+/*
+ * The cpu state corresponding to 'host_pc' is restored.
+ * When reset_icount is true, current TB will be interrupted and
+ * icount should be recalculated.
+ */
+static void cpu_restore_state_from_tb(CPUState *cpu, TranslationBlock *tb,
+ uintptr_t host_pc, bool reset_icount)
+{
+ uint64_t data[TARGET_INSN_START_WORDS];
+#ifdef CONFIG_PROFILER
+ TCGProfile *prof = &tcg_ctx->prof;
+ int64_t ti = profile_getclock();
+#endif
+ int insns_left = cpu_unwind_data_from_tb(tb, host_pc, data);
+
+ if (insns_left < 0) {
+ return;
+ }
- found:
if (reset_icount && (tb_cflags(tb) & CF_USE_ICOUNT)) {
assert(icount_enabled());
- /* Reset the cycle counter to the start of the block
- and shift if to the number of actually executed instructions */
- cpu_neg(cpu)->icount_decr.u16.low += num_insns - i;
+ /*
+ * Reset the cycle counter to the start of the block and
+ * shift if to the number of actually executed instructions.
+ */
+ cpu_neg(cpu)->icount_decr.u16.low += insns_left;
}
cpu->cc->tcg_ops->restore_state_to_opc(cpu, tb, data);
@@ -375,7 +387,6 @@ static int cpu_restore_state_from_tb(CPUState *cpu,
TranslationBlock *tb,
prof->restore_time + profile_getclock() - ti);
qatomic_set(&prof->restore_count, prof->restore_count + 1);
#endif
- return 0;
}
bool cpu_restore_state(CPUState *cpu, uintptr_t host_pc, bool will_exit)
@@ -408,6 +419,17 @@ bool cpu_restore_state(CPUState *cpu, uintptr_t host_pc,
bool will_exit)
return false;
}
+bool cpu_unwind_state_data(CPUState *cpu, uintptr_t host_pc, uint64_t *data)
+{
+ if (in_code_gen_buffer((const void *)(host_pc - tcg_splitwx_diff))) {
+ TranslationBlock *tb = tcg_tb_lookup(host_pc);
+ if (tb) {
+ return cpu_unwind_data_from_tb(tb, host_pc, data) >= 0;
+ }
+ }
+ return false;
+}
+
void page_init(void)
{
page_size_init();
--
2.34.1
