We add new option trace-privilege-level=bool, which will create a
separate trace for each privilege level.
This allows to follow changes of privilege during execution.
We implement aarch64 operations to track current privilege level
accordingly.
Signed-off-by: Pierrick Bouvier <pierrick.bouv...@linaro.org>
---
contrib/plugins/uftrace.c | 189 ++++++++++++++++++++++++++++++++++++--
1 file changed, 181 insertions(+), 8 deletions(-)
diff --git a/contrib/plugins/uftrace.c b/contrib/plugins/uftrace.c
index 402a242433e..7737626da2f 100644
--- a/contrib/plugins/uftrace.c
+++ b/contrib/plugins/uftrace.c
@@ -44,19 +44,39 @@ typedef struct {
void (*init)(Cpu *cpu);
void (*end)(Cpu *cpu);
uint64_t (*get_frame_pointer)(Cpu *cpu);
+ uint8_t (*get_privilege_level)(Cpu *cpu);
+ uint8_t (*num_privilege_levels)(void);
+ const char *(*get_privilege_level_name)(uint8_t pl);
bool (*does_insn_modify_frame_pointer)(const char *disas);
} CpuOps;
typedef struct Cpu {
Trace *trace;
Callstack *cs;
+ uint8_t privilege_level;
+ GArray *traces; /* Trace *traces [] */
GByteArray *buf;
CpuOps ops;
void *arch;
} Cpu;
+typedef enum {
+ AARCH64_EL0_SECURE,
+ AARCH64_EL0_NONSECURE,
+ AARCH64_EL0_REALM,
+ AARCH64_EL1_SECURE,
+ AARCH64_EL1_NONSECURE,
+ AARCH64_EL1_REALM,
+ AARCH64_EL2_SECURE,
+ AARCH64_EL2_NONSECURE,
+ AARCH64_EL2_REALM,
+ AARCH64_EL3,
+} Aarch64PrivilegeLevel;
+
typedef struct {
struct qemu_plugin_register *reg_fp;
+ struct qemu_plugin_register *reg_cpsr;
+ struct qemu_plugin_register *reg_scr_el3;
} Aarch64Cpu;
typedef struct {
@@ -72,6 +92,7 @@ typedef enum {
} UftraceRecordType;
static struct qemu_plugin_scoreboard *score;
+static bool trace_privilege_level;
static CpuOps arch_ops;
static uint64_t gettime_ns(void)
@@ -248,6 +269,16 @@ static uint64_t cpu_read_register64(Cpu *cpu, struct
qemu_plugin_register *reg)
return *((uint64_t *) buf->data);
}
+static uint32_t cpu_read_register32(Cpu *cpu, struct qemu_plugin_register *reg)
+{
+ GByteArray *buf = cpu->buf;
+ g_byte_array_set_size(buf, 0);
+ size_t sz = qemu_plugin_read_register(reg, buf);
+ g_assert(sz == 4);
+ g_assert(buf->len == 4);
+ return *((uint32_t *) buf->data);
+}
+
static uint64_t cpu_read_memory64(Cpu *cpu, uint64_t addr)
{
g_assert(addr);
@@ -305,6 +336,68 @@ static struct qemu_plugin_register
*plugin_find_register(const char *name)
return NULL;
}
+static uint8_t aarch64_num_privilege_levels(void)
+{
+ return AARCH64_EL3 + 1;
+}
+
+static const char *aarch64_get_privilege_level_name(uint8_t pl)
+{
+ switch (pl) {
+ case AARCH64_EL0_SECURE: return "S-EL0";
+ case AARCH64_EL0_NONSECURE: return "NS-EL0";
+ case AARCH64_EL0_REALM: return "R-EL0";
+ case AARCH64_EL1_SECURE: return "S-EL1";
+ case AARCH64_EL1_NONSECURE: return "NS-EL1";
+ case AARCH64_EL1_REALM: return "R-EL1";
+ case AARCH64_EL2_SECURE: return "S-EL2";
+ case AARCH64_EL2_NONSECURE: return "NS-EL2";
+ case AARCH64_EL2_REALM: return "R-EL2";
+ case AARCH64_EL3: return "EL3";
+ default:
+ g_assert_not_reached();
+ }
+}
+
+static uint8_t aarch64_get_privilege_level(Cpu *cpu_)
+{
+ Aarch64Cpu *cpu = cpu_->arch;
+ /*
+ * QEMU gdbstub does not provide access to CurrentEL,
+ * so we use CPSR instead.
+ */
+ uint8_t el = cpu_read_register32(cpu_, cpu->reg_cpsr) >> 2 & 0b11;
+
+ if (el == 3) {
+ return AARCH64_EL3;
+ }
+
+ uint8_t ss = AARCH64_EL0_SECURE;
+ if (!cpu->reg_scr_el3) {
+ ss = AARCH64_EL0_NONSECURE;
+ }
+ uint64_t scr_el3 = cpu_read_register64(cpu_, cpu->reg_scr_el3);
+ uint64_t ns = (scr_el3 >> 0) & 0b1;
+ uint64_t nse = (scr_el3 >> 62) & 0b1;
+ switch (nse << 1 | ns) {
+ case 0b00:
+ ss = AARCH64_EL0_SECURE;
+ break;
+ case 0b01:
+ ss = AARCH64_EL0_NONSECURE;
+ break;
+ case 0b11:
+ ss = AARCH64_EL0_REALM;
+ break;
+ default:
+ g_assert_not_reached();
+ }
+
+ const uint8_t num_ss = 3;
+ Aarch64PrivilegeLevel pl = el * num_ss + ss;
+ return pl;
+}
+
static uint64_t aarch64_get_frame_pointer(Cpu *cpu_)
{
Aarch64Cpu *cpu = cpu_->arch;
@@ -321,6 +414,10 @@ static void aarch64_init(Cpu *cpu_)
"available. Please use an AArch64 cpu (or -cpu
max).\n");
g_abort();
}
+ cpu->reg_cpsr = plugin_find_register("cpsr");
+ g_assert(cpu->reg_cpsr);
+ cpu->reg_scr_el3 = plugin_find_register("SCR_EL3");
+ /* scr_el3 is optional */
}
static void aarch64_end(Cpu *cpu)
@@ -342,9 +439,34 @@ static CpuOps aarch64_ops = {
.init = aarch64_init,
.end = aarch64_end,
.get_frame_pointer = aarch64_get_frame_pointer,
+ .get_privilege_level = aarch64_get_privilege_level,
+ .num_privilege_levels = aarch64_num_privilege_levels,
+ .get_privilege_level_name = aarch64_get_privilege_level_name,
.does_insn_modify_frame_pointer = aarch64_does_insn_modify_frame_pointer,
};
+static void track_privilege_change(unsigned int cpu_index, void *udata)
+{
+ Cpu *cpu = qemu_plugin_scoreboard_find(score, cpu_index);
+ uint8_t new_pl = cpu->ops.get_privilege_level(cpu);
+
+ if (new_pl == cpu->privilege_level) {
+ return;
+ }
+
+ uint64_t pc = (uintptr_t) udata;
+ uint64_t timestamp = gettime_ns();
+
+ trace_exit_stack(cpu->trace, cpu->cs, timestamp);
+ callstack_clear(cpu->cs);
+
+ cpu->privilege_level = new_pl;
+ cpu->trace = g_array_index(cpu->traces, Trace*, new_pl);
+
+ cpu_unwind_stack(cpu, cpu->ops.get_frame_pointer(cpu), pc);
+ trace_enter_stack(cpu->trace, cpu->cs, timestamp);
+}
+
static void track_callstack(unsigned int cpu_index, void *udata)
{
uint64_t pc = (uintptr_t) udata;
@@ -397,6 +519,13 @@ static void track_callstack(unsigned int cpu_index, void
*udata)
static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
{
size_t n_insns = qemu_plugin_tb_n_insns(tb);
+ uintptr_t tb_pc = qemu_plugin_tb_vaddr(tb);
+
+ if (trace_privilege_level) {
+ qemu_plugin_register_vcpu_tb_exec_cb(tb, track_privilege_change,
+ QEMU_PLUGIN_CB_R_REGS,
+ (void *) tb_pc);
+ }
/*
* We instrument all instructions following one that might have updated
@@ -429,18 +558,36 @@ static void vcpu_init(qemu_plugin_id_t id, unsigned int
vcpu_index)
cpu->ops.init(cpu);
cpu->buf = g_byte_array_new();
+ cpu->traces = g_array_new(0, 0, sizeof(Trace *));
g_assert(vcpu_index < UINT32_MAX / 100);
- /* trace_id is: cpu_number * 100 */
+ g_assert(cpu->ops.num_privilege_levels() < 100);
+ /* trace_id is: cpu_number * 100 + privilege_level */
uint32_t trace_id = (vcpu_index + 1) * 100;
- g_autoptr(GString) trace_name = g_string_new(NULL);
- g_string_append_printf(trace_name, "cpu%u", vcpu_index);
- cpu->trace = trace_new(trace_id, trace_name);
- /* create/truncate trace file */
- trace_flush(cpu->trace, false);
+ if (trace_privilege_level) {
+ for (uint8_t pl = 0; pl < cpu->ops.num_privilege_levels(); ++pl) {
+ g_autoptr(GString) trace_name = g_string_new(NULL);
+ g_string_append_printf(trace_name, "cpu%u %s", vcpu_index,
+ cpu->ops.get_privilege_level_name(pl));
+ Trace *t = trace_new(trace_id + pl, trace_name);
+ g_array_append_val(cpu->traces, t);
+ }
+ } else {
+ g_autoptr(GString) trace_name = g_string_new(NULL);
+ g_string_append_printf(trace_name, "cpu%u", vcpu_index);
+ Trace *t = trace_new(trace_id, trace_name);
+ g_array_append_val(cpu->traces, t);
+ }
+
+ for (size_t i = 0; i < cpu->traces->len; ++i) {
+ /* create/truncate trace files */
+ Trace *t = g_array_index(cpu->traces, Trace*, i);
+ trace_flush(t, false);
+ }
cpu->cs = callstack_new();
+ cpu->trace = g_array_index(cpu->traces, Trace*, cpu->privilege_level);
}
static void vcpu_end(unsigned int vcpu_index)
@@ -448,7 +595,12 @@ static void vcpu_end(unsigned int vcpu_index)
Cpu *cpu = qemu_plugin_scoreboard_find(score, vcpu_index);
g_byte_array_free(cpu->buf, true);
- trace_free(cpu->trace);
+ for (size_t i = 0; i < cpu->traces->len; ++i) {
+ Trace *t = g_array_index(cpu->traces, Trace*, i);
+ trace_free(t);
+ }
+
+ g_array_free(cpu->traces, true);
callstack_free(cpu->cs);
memset(cpu, 0, sizeof(Cpu));
}
@@ -457,7 +609,13 @@ static void at_exit(qemu_plugin_id_t id, void *data)
{
for (size_t i = 0; i < qemu_plugin_num_vcpus(); ++i) {
Cpu *cpu = qemu_plugin_scoreboard_find(score, i);
- trace_flush(cpu->trace, true);
+ for (size_t j = 0; j < cpu->traces->len; ++j) {
+ Trace *t = g_array_index(cpu->traces, Trace*, j);
+ trace_flush(t, true);
+ }
+ }
+
+ for (size_t i = 0; i < qemu_plugin_num_vcpus(); ++i) {
vcpu_end(i);
}
@@ -468,6 +626,21 @@ QEMU_PLUGIN_EXPORT int
qemu_plugin_install(qemu_plugin_id_t id,
const qemu_info_t *info,
int argc, char **argv)
{
+ for (int i = 0; i < argc; i++) {
+ char *opt = argv[i];
+ g_auto(GStrv) tokens = g_strsplit(opt, "=", 2);
+ if (g_strcmp0(tokens[0], "trace-privilege-level") == 0) {
+ if (!qemu_plugin_bool_parse(tokens[0], tokens[1],
+ &trace_privilege_level)) {
+ fprintf(stderr, "boolean argument parsing failed: %s\n", opt);
+ return -1;
+ }
+ } else {
+ fprintf(stderr, "option parsing failed: %s\n", opt);
+ return -1;
+ }
+ }
+
if (!strcmp(info->target_name, "aarch64")) {
arch_ops = aarch64_ops;
} else {
--
2.47.2
