Bmach: rseqsliceprobe: improve output
This commit is contained in:
+162
-24
@@ -11,8 +11,13 @@
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#include <sys/auxv.h>
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#include <sys/prctl.h>
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#include <sys/syscall.h>
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#include <sys/utsname.h>
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#include <unistd.h>
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#ifndef ENOTSUPP
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#define ENOTSUPP 524
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#endif
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#if defined(__x86_64__)
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#ifndef ARCH_GET_FS
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#define ARCH_GET_FS 0x1003
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@@ -83,15 +88,33 @@ struct rseq_compat {
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uint8_t reserved;
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} __attribute__((aligned(32)));
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struct prctl_probe_result {
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bool ok;
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int value;
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int err;
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};
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alignas(32) static thread_local unsigned char local_rseq_storage[512];
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static unsigned int g_rseq_feature_size;
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static unsigned int g_rseq_alloc_size;
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static unsigned int g_rseq_align;
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static unsigned long g_aux_rseq_feature_size;
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static unsigned long g_aux_rseq_align;
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static struct rseq *g_registered_rseq;
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static struct rseq_compat *g_registered_rseq_compat;
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static bool g_own_registration;
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static const char *yes_no(bool value)
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{
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return value ? "yes" : "no";
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}
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static const char *set_clear(bool value)
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{
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return value ? "set" : "clear";
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}
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static int get_thread_pointer(uintptr_t *tp_out)
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{
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#if defined(__x86_64__)
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@@ -147,6 +170,7 @@ static const char *errno_name(int err)
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case EINVAL: return "EINVAL";
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case ENOSYS: return "ENOSYS";
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case ENOTSUP: return "ENOTSUP";
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case ENOTSUPP: return "ENOTSUPP";
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case ENXIO: return "ENXIO";
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case EPERM: return "EPERM";
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case EBUSY: return "EBUSY";
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@@ -154,6 +178,26 @@ static const char *errno_name(int err)
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}
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}
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static const char *prctl_failure_meaning(int err)
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{
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switch (err) {
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case EINVAL:
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return "the prctl operation or argument is not accepted by this kernel";
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case ENOTSUPP:
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return "the prctl operation exists, but the slice extension is not supported here";
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case EPERM:
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return "the kernel denied the requested operation";
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default:
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return "the kernel returned an unclassified failure";
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}
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}
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static void print_errno_status(const char *label, int err)
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{
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std::printf("%s: errno=%d (%s: %s)\n",
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label, err, errno_name(err), std::strerror(err));
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}
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static unsigned int max_u32(unsigned int a, unsigned int b)
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{
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return a > b ? a : b;
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@@ -174,11 +218,13 @@ static void print_registration_source(void)
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static int setup_rseq(void)
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{
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unsigned long aux_feature_size = getauxval(AT_RSEQ_FEATURE_SIZE);
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unsigned long aux_align = getauxval(AT_RSEQ_ALIGN);
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g_aux_rseq_feature_size = getauxval(AT_RSEQ_FEATURE_SIZE);
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g_aux_rseq_align = getauxval(AT_RSEQ_ALIGN);
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g_rseq_feature_size = aux_feature_size ? static_cast<unsigned int>(aux_feature_size) : 20U;
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g_rseq_align = aux_align ? static_cast<unsigned int>(aux_align) : 32U;
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g_rseq_feature_size = g_aux_rseq_feature_size ?
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static_cast<unsigned int>(g_aux_rseq_feature_size) : 20U;
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g_rseq_align = g_aux_rseq_align ?
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static_cast<unsigned int>(g_aux_rseq_align) : 32U;
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g_rseq_alloc_size = max_u32(g_rseq_feature_size, 32U);
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if (&__rseq_size != nullptr && __rseq_size != 0) {
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@@ -191,6 +237,7 @@ static int setup_rseq(void)
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g_registered_rseq = reinterpret_cast<struct rseq *>(tp + __rseq_offset);
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g_registered_rseq_compat = reinterpret_cast<struct rseq_compat *>(tp + __rseq_offset);
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g_own_registration = false;
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if (__rseq_size < g_rseq_feature_size)
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g_rseq_feature_size = __rseq_size;
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if (__rseq_size > g_rseq_alloc_size)
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@@ -237,22 +284,116 @@ static void teardown_rseq(void)
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std::perror("rseq unregister");
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}
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static prctl_probe_result probe_prctl_get(void)
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{
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errno = 0;
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int rc = prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET,
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0UL, 0UL, 0UL);
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int saved_errno = errno;
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if (rc >= 0)
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return { true, rc, 0 };
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return { false, -1, saved_errno };
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}
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static prctl_probe_result probe_prctl_set(unsigned long value)
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{
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errno = 0;
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int rc = prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_SET,
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value, 0UL, 0UL);
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int saved_errno = errno;
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if (rc >= 0)
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return { true, rc, 0 };
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return { false, -1, saved_errno };
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}
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static void print_prctl_result(const char *label, const prctl_probe_result &result)
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{
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if (result.ok) {
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std::printf("%s: ok, value=%d\n", label, result.value);
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return;
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}
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print_errno_status(label, result.err);
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std::printf("%s meaning: %s\n", label, prctl_failure_meaning(result.err));
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}
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static void print_kernel_version(void)
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{
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struct utsname uts;
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if (uname(&uts) != 0) {
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std::perror("uname");
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return;
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}
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std::printf("kernel: %s %s %s %s\n",
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uts.sysname, uts.release, uts.version, uts.machine);
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}
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static void print_slice_status_summary(bool has_slice_ctrl, bool flags_available,
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const prctl_probe_result &get_result)
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{
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bool flag_available = flags_available &&
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(g_registered_rseq_compat->flags & RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE);
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bool flag_enabled = flags_available &&
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(g_registered_rseq_compat->flags & RSEQ_CS_FLAG_SLICE_EXT_ENABLED);
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bool prctl_enabled = get_result.ok &&
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(get_result.value & PR_RSEQ_SLICE_EXT_ENABLE);
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std::printf("status: rseq syscall registered: yes\n");
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std::printf("status: rseq extensible feature area: %s\n",
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yes_no(g_rseq_feature_size > 20U));
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std::printf("status: rseq slice_ctrl field present: %s\n",
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yes_no(has_slice_ctrl));
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std::printf("status: rseq slice extension available flag: %s\n",
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flags_available ? set_clear(flag_available) : "unavailable");
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std::printf("status: rseq slice extension enabled flag: %s\n",
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flags_available ? set_clear(flag_enabled) : "unavailable");
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std::printf("status: PR_RSEQ_SLICE_EXTENSION GET usable: %s\n",
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yes_no(get_result.ok));
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if (get_result.ok) {
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std::printf("status: PR_RSEQ_SLICE_EXTENSION enabled: %s\n",
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yes_no(prctl_enabled));
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std::printf("status: rseq slice extension availability: %s\n",
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prctl_enabled || flag_available ? "available" : "available but disabled");
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return;
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}
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if (get_result.err == ENOTSUPP) {
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std::printf("status: rseq slice extension availability: not supported by this kernel/arch/config\n");
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return;
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}
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if (get_result.err == EINVAL) {
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std::printf("status: rseq slice extension availability: no accepted prctl API on this kernel\n");
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return;
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}
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std::printf("status: rseq slice extension availability: unknown\n");
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}
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static void probe_slice_extension(void)
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{
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bool has_slice_ctrl = feature_present(offsetof(struct rseq_compat, slice_ctrl) +
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sizeof(g_registered_rseq_compat->slice_ctrl));
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bool flags_available = feature_present(offsetof(struct rseq_compat, flags) +
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sizeof(g_registered_rseq_compat->flags));
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prctl_probe_result prctl_get = probe_prctl_get();
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unsigned int cpu = 0;
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unsigned int node = 0;
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std::printf("AT_RSEQ_FEATURE_SIZE: %u\n", g_rseq_feature_size);
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std::printf("AT_RSEQ_ALIGN: %u\n", g_rseq_align);
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print_kernel_version();
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std::printf("AT_RSEQ_FEATURE_SIZE raw: %lu\n", g_aux_rseq_feature_size);
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std::printf("AT_RSEQ_ALIGN raw: %lu\n", g_aux_rseq_align);
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std::printf("effective rseq feature size: %u\n", g_rseq_feature_size);
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std::printf("effective rseq alignment: %u\n", g_rseq_align);
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std::printf("registered rseq size: %u\n", g_rseq_alloc_size);
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print_registration_source();
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if (&__rseq_size != nullptr) {
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std::printf("libc __rseq_size=%u __rseq_offset=%td __rseq_flags=0x%x\n",
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__rseq_size, __rseq_offset, __rseq_flags);
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}
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std::printf("registered rseq addr: %p\n", static_cast<void *>(g_registered_rseq));
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std::printf("struct rseq has slice_ctrl field available: %s\n",
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has_slice_ctrl ? "yes" : "no");
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yes_no(has_slice_ctrl));
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if (sys_getcpu(&cpu, &node) == 0)
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std::printf("getcpu(): cpu=%u node=%u\n", cpu, node);
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@@ -273,9 +414,9 @@ static void probe_slice_extension(void)
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if (flags_available) {
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std::printf("rseq flags=0x%x\n", g_registered_rseq_compat->flags);
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std::printf("slice ext available bit: %s\n",
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(g_registered_rseq_compat->flags & RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE) ? "set" : "clear");
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set_clear(g_registered_rseq_compat->flags & RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE));
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std::printf("slice ext enabled bit: %s\n",
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(g_registered_rseq_compat->flags & RSEQ_CS_FLAG_SLICE_EXT_ENABLED) ? "set" : "clear");
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set_clear(g_registered_rseq_compat->flags & RSEQ_CS_FLAG_SLICE_EXT_ENABLED));
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}
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if (has_slice_ctrl) {
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@@ -285,22 +426,19 @@ static void probe_slice_extension(void)
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g_registered_rseq_compat->slice_ctrl.all);
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}
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errno = 0;
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int rc = prctl(PR_RSEQ_SLICE_EXTENSION, PR_RSEQ_SLICE_EXTENSION_GET, 0UL, 0UL, 0UL);
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int saved_errno = errno;
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if (rc >= 0) {
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std::printf("prctl(GET) result=%d\n", rc);
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std::printf("slice extension runtime availability: yes\n");
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std::printf("slice extension enabled for this thread: %s\n",
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(rc & PR_RSEQ_SLICE_EXT_ENABLE) ? "yes" : "no");
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return;
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print_prctl_result("prctl(PR_RSEQ_SLICE_EXTENSION, GET)", prctl_get);
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if (prctl_get.ok) {
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prctl_probe_result set_enable = probe_prctl_set(PR_RSEQ_SLICE_EXT_ENABLE);
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print_prctl_result("prctl(PR_RSEQ_SLICE_EXTENSION, SET enable)",
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set_enable);
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prctl_probe_result after_enable = probe_prctl_get();
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print_prctl_result("prctl(PR_RSEQ_SLICE_EXTENSION, GET after enable)",
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after_enable);
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prctl_probe_result set_disable = probe_prctl_set(0UL);
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print_prctl_result("prctl(PR_RSEQ_SLICE_EXTENSION, SET disable)",
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set_disable);
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}
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std::printf("prctl(GET) failed: errno=%d (%s)\n",
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saved_errno, errno_name(saved_errno));
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std::printf("slice extension runtime availability: %s\n",
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saved_errno == EINVAL ? "no" : "unknown");
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print_slice_status_summary(has_slice_ctrl, flags_available, prctl_get);
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}
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int main()
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