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Support nested uc_emu_start calls

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This commit is contained in:
lazymio 2021-11-16 21:07:03 +01:00
parent 43c643d4af
commit 247ffbe0e8
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GPG Key ID: DFF27E34A47CB873
5 changed files with 54 additions and 2 deletions
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6
include/uc_priv.h
View File

@ -12,6 +12,9 @@
#include "unicorn/unicorn.h"
#include "list.h"
// The max recursive nested uc_emu_start levels
#define UC_MAX_NESTED_LEVEL (64)
// These are masks of supported modes for each cpu/arch.
// They should be updated when changes are made to the uc_mode enum typedef.
#define UC_MODE_ARM_MASK \
@ -342,6 +345,9 @@ struct uc_struct {
bool no_exit_request; // Disable check_exit_request temporarily. A
// workaround to treat the IT block as a whole block.
bool init_done; // Whether the initialization is done.
sigjmp_buf jmp_bufs[UC_MAX_NESTED_LEVEL]; // To support nested uc_emu_start
int nested_level; // Current nested_level
};
// Metadata stub for the variable-size cpu context used with uc_context_*()

2
qemu/accel/tcg/cpu-exec-common.c
View File

@ -40,7 +40,7 @@ void cpu_loop_exit(CPUState *cpu)
tb_exec_unlock(cpu->uc->tcg_ctx);
/* Undo the setting in cpu_tb_exec. */
cpu->can_do_io = 1;
siglongjmp(cpu->jmp_env, 1);
siglongjmp(cpu->uc->jmp_bufs[cpu->uc->nested_level - 1], 1);
}
void cpu_loop_exit_restore(CPUState *cpu, uintptr_t pc)

4
qemu/accel/tcg/cpu-exec.c
View File

@ -551,8 +551,10 @@ int cpu_exec(struct uc_struct *uc, CPUState *cpu)
*/
// init_delay_params(&sc, cpu);
// Unicorn: We would like to support nested uc_emu_start calls.
/* prepare setjmp context for exception handling */
if (sigsetjmp(cpu->jmp_env, 0) != 0) {
// if (sigsetjmp(cpu->jmp_env, 0) != 0) {
if (sigsetjmp(uc->jmp_bufs[uc->nested_level - 1], 0) != 0) {
#if defined(__clang__) || !QEMU_GNUC_PREREQ(4, 6)
/* Some compilers wrongly smash all local variables after
* siglongjmp. There were bug reports for gcc 4.5.0 and clang.

34
tests/unit/test_x86.c
View File

@ -813,6 +813,39 @@ static void test_x86_cmpxchg()
OK(uc_close(uc));
}
static void test_x86_nested_emu_start_cb(uc_engine *uc, uint64_t addr,
size_t size, void *data)
{
OK(uc_emu_start(uc, code_start + 1, code_start + 2, 0, 0));
}
static void test_x86_nested_emu_start()
{
uc_engine *uc;
char code[] = "\x41\x4a"; // INC ecx; DEC edx;
int r_ecx = 0x1234;
int r_edx = 0x7890;
uc_hook h;
uc_common_setup(&uc, UC_ARCH_X86, UC_MODE_32, code, sizeof(code) - 1);
OK(uc_reg_write(uc, UC_X86_REG_ECX, &r_ecx));
OK(uc_reg_write(uc, UC_X86_REG_EDX, &r_edx));
// Emulate DEC in the nested hook.
OK(uc_hook_add(uc, &h, UC_HOOK_CODE, test_x86_nested_emu_start_cb, NULL,
code_start, code_start));
// Emulate INC
OK(uc_emu_start(uc, code_start, code_start + 1, 0, 0));
OK(uc_reg_read(uc, UC_X86_REG_ECX, &r_ecx));
OK(uc_reg_read(uc, UC_X86_REG_EDX, &r_edx));
TEST_CHECK(r_ecx == 0x1235);
TEST_CHECK(r_edx == 0x788f);
OK(uc_close(uc));
}
TEST_LIST = {{"test_x86_in", test_x86_in},
{"test_x86_out", test_x86_out},
{"test_x86_mem_hook_all", test_x86_mem_hook_all},
@ -838,4 +871,5 @@ TEST_LIST = {{"test_x86_in", test_x86_in},
{"test_x86_clear_empty_tb", test_x86_clear_empty_tb},
{"test_x86_hook_tcg_op", test_x86_hook_tcg_op},
{"test_x86_cmpxchg", test_x86_cmpxchg},
{"test_x86_nested_emu_start", test_x86_nested_emu_start},
{NULL, NULL}};

10
uc.c
View File

@ -700,6 +700,14 @@ uc_err uc_emu_start(uc_engine *uc, uint64_t begin, uint64_t until,
UC_INIT(uc);
// Advance the nested levels. We must decrease the level count by one when
// we return from uc_emu_start.
if (uc->nested_level >= UC_MAX_NESTED_LEVEL) {
// We can't support so many nested levels.
return UC_ERR_RESOURCE;
}
uc->nested_level++;
switch (uc->arch) {
default:
break;
@ -786,6 +794,7 @@ uc_err uc_emu_start(uc_engine *uc, uint64_t begin, uint64_t until,
// restore to append mode for uc_hook_add()
uc->hook_insert = 0;
if (err != UC_ERR_OK) {
uc->nested_level--;
return err;
}
}
@ -814,6 +823,7 @@ uc_err uc_emu_start(uc_engine *uc, uint64_t begin, uint64_t until,
qemu_thread_join(&uc->timer);
}
uc->nested_level--;
return uc->invalid_error;
}