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accel/tcg: Introduce cpu_unwind_state_data

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Add a way to examine the unwind data without actually
restoring the data back into env.

Reviewed-by: Claudio Fontana <cfontana@suse.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2022-10-24 22:15:04 +10:00
parent 9dd1d56e57
commit 6392bd6b90
3 changed files with 68 additions and 31 deletions
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4
accel/tcg/internal.h
View File

@ -106,8 +106,8 @@ void tb_reset_jump(TranslationBlock *tb, int n);
TranslationBlock *tb_link_page(TranslationBlock *tb, tb_page_addr_t phys_pc,
tb_page_addr_t phys_page2);
bool tb_invalidate_phys_page_unwind(tb_page_addr_t addr, uintptr_t pc);
int cpu_restore_state_from_tb(CPUState *cpu, TranslationBlock *tb,
uintptr_t searched_pc, bool reset_icount);
void cpu_restore_state_from_tb(CPUState *cpu, TranslationBlock *tb,
uintptr_t host_pc, bool reset_icount);
/* Return the current PC from CPU, which may be cached in TB. */
static inline target_ulong log_pc(CPUState *cpu, const TranslationBlock *tb)

74
accel/tcg/translate-all.c
View File

@ -247,52 +247,66 @@ 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.
*/
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);
}
/* Reconstruct the stored insn data while looking for the point at
which the end of the insn exceeds the searched_pc. */
/*
* Reconstruct the stored insn data while looking for the point
* at which the end of the insn exceeds host_pc.
*/
for (i = 0; i < num_insns; ++i) {
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.
*/
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);
@ -302,7 +316,6 @@ 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)
@ -335,6 +348,17 @@ 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();

21
include/exec/exec-all.h
View File

@ -39,20 +39,33 @@ typedef ram_addr_t tb_page_addr_t;
#define TB_PAGE_ADDR_FMT RAM_ADDR_FMT
#endif
/**
* cpu_unwind_state_data:
* @cpu: the cpu context
* @host_pc: the host pc within the translation
* @data: output data
*
* Attempt to load the the unwind state for a host pc occurring in
* translated code. If @host_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
* @searched_pc: the host PC the fault occurred at
* @cpu: the cpu context
* @host_pc: the host pc within the translation
* @will_exit: true if the TB executed will be interrupted after some
cpu adjustments. Required for maintaining the correct
icount valus
* @return: true if state was restored, false otherwise
*
* Attempt to restore the state for a fault occurring in translated
* code. If the searched_pc is not in translated code no state is
* code. If @host_pc is not in translated code no state is
* restored and the function returns false.
*/
bool cpu_restore_state(CPUState *cpu, uintptr_t searched_pc, bool will_exit);
bool cpu_restore_state(CPUState *cpu, uintptr_t host_pc, bool will_exit);
G_NORETURN void cpu_loop_exit_noexc(CPUState *cpu);
G_NORETURN void cpu_loop_exit(CPUState *cpu);