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Diffstat (limited to 'tools/lib/bpf/libbpf.c')
-rw-r--r--tools/lib/bpf/libbpf.c214
1 files changed, 174 insertions, 40 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 77ae83308199..431409a2336b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1694,7 +1694,7 @@ static int set_kcfg_value_tri(struct extern_desc *ext, void *ext_val,
switch (ext->kcfg.type) {
case KCFG_BOOL:
if (value == 'm') {
- pr_warn("extern (kcfg) %s=%c should be tristate or char\n",
+ pr_warn("extern (kcfg) '%s': value '%c' implies tristate or char type\n",
ext->name, value);
return -EINVAL;
}
@@ -1715,7 +1715,7 @@ static int set_kcfg_value_tri(struct extern_desc *ext, void *ext_val,
case KCFG_INT:
case KCFG_CHAR_ARR:
default:
- pr_warn("extern (kcfg) %s=%c should be bool, tristate, or char\n",
+ pr_warn("extern (kcfg) '%s': value '%c' implies bool, tristate, or char type\n",
ext->name, value);
return -EINVAL;
}
@@ -1729,7 +1729,8 @@ static int set_kcfg_value_str(struct extern_desc *ext, char *ext_val,
size_t len;
if (ext->kcfg.type != KCFG_CHAR_ARR) {
- pr_warn("extern (kcfg) %s=%s should be char array\n", ext->name, value);
+ pr_warn("extern (kcfg) '%s': value '%s' implies char array type\n",
+ ext->name, value);
return -EINVAL;
}
@@ -1743,7 +1744,7 @@ static int set_kcfg_value_str(struct extern_desc *ext, char *ext_val,
/* strip quotes */
len -= 2;
if (len >= ext->kcfg.sz) {
- pr_warn("extern (kcfg) '%s': long string config %s of (%zu bytes) truncated to %d bytes\n",
+ pr_warn("extern (kcfg) '%s': long string '%s' of (%zu bytes) truncated to %d bytes\n",
ext->name, value, len, ext->kcfg.sz - 1);
len = ext->kcfg.sz - 1;
}
@@ -1800,13 +1801,20 @@ static bool is_kcfg_value_in_range(const struct extern_desc *ext, __u64 v)
static int set_kcfg_value_num(struct extern_desc *ext, void *ext_val,
__u64 value)
{
- if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR) {
- pr_warn("extern (kcfg) %s=%llu should be integer\n",
+ if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR &&
+ ext->kcfg.type != KCFG_BOOL) {
+ pr_warn("extern (kcfg) '%s': value '%llu' implies integer, char, or boolean type\n",
ext->name, (unsigned long long)value);
return -EINVAL;
}
+ if (ext->kcfg.type == KCFG_BOOL && value > 1) {
+ pr_warn("extern (kcfg) '%s': value '%llu' isn't boolean compatible\n",
+ ext->name, (unsigned long long)value);
+ return -EINVAL;
+
+ }
if (!is_kcfg_value_in_range(ext, value)) {
- pr_warn("extern (kcfg) %s=%llu value doesn't fit in %d bytes\n",
+ pr_warn("extern (kcfg) '%s': value '%llu' doesn't fit in %d bytes\n",
ext->name, (unsigned long long)value, ext->kcfg.sz);
return -ERANGE;
}
@@ -1870,16 +1878,19 @@ static int bpf_object__process_kconfig_line(struct bpf_object *obj,
/* assume integer */
err = parse_u64(value, &num);
if (err) {
- pr_warn("extern (kcfg) %s=%s should be integer\n",
- ext->name, value);
+ pr_warn("extern (kcfg) '%s': value '%s' isn't a valid integer\n", ext->name, value);
return err;
}
+ if (ext->kcfg.type != KCFG_INT && ext->kcfg.type != KCFG_CHAR) {
+ pr_warn("extern (kcfg) '%s': value '%s' implies integer type\n", ext->name, value);
+ return -EINVAL;
+ }
err = set_kcfg_value_num(ext, ext_val, num);
break;
}
if (err)
return err;
- pr_debug("extern (kcfg) %s=%s\n", ext->name, value);
+ pr_debug("extern (kcfg) '%s': set to %s\n", ext->name, value);
return 0;
}
@@ -3687,7 +3698,7 @@ static int bpf_object__collect_externs(struct bpf_object *obj)
ext->kcfg.type = find_kcfg_type(obj->btf, t->type,
&ext->kcfg.is_signed);
if (ext->kcfg.type == KCFG_UNKNOWN) {
- pr_warn("extern (kcfg) '%s' type is unsupported\n", ext_name);
+ pr_warn("extern (kcfg) '%s': type is unsupported\n", ext_name);
return -ENOTSUP;
}
} else if (strcmp(sec_name, KSYMS_SEC) == 0) {
@@ -4659,6 +4670,8 @@ static int probe_kern_btf_enum64(void)
strs, sizeof(strs)));
}
+static int probe_kern_syscall_wrapper(void);
+
enum kern_feature_result {
FEAT_UNKNOWN = 0,
FEAT_SUPPORTED = 1,
@@ -4727,6 +4740,9 @@ static struct kern_feature_desc {
[FEAT_BTF_ENUM64] = {
"BTF_KIND_ENUM64 support", probe_kern_btf_enum64,
},
+ [FEAT_SYSCALL_WRAPPER] = {
+ "Kernel using syscall wrapper", probe_kern_syscall_wrapper,
+ },
};
bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id)
@@ -7287,14 +7303,14 @@ static int kallsyms_cb(unsigned long long sym_addr, char sym_type,
return 0;
if (ext->is_set && ext->ksym.addr != sym_addr) {
- pr_warn("extern (ksym) '%s' resolution is ambiguous: 0x%llx or 0x%llx\n",
+ pr_warn("extern (ksym) '%s': resolution is ambiguous: 0x%llx or 0x%llx\n",
sym_name, ext->ksym.addr, sym_addr);
return -EINVAL;
}
if (!ext->is_set) {
ext->is_set = true;
ext->ksym.addr = sym_addr;
- pr_debug("extern (ksym) %s=0x%llx\n", sym_name, sym_addr);
+ pr_debug("extern (ksym) '%s': set to 0x%llx\n", sym_name, sym_addr);
}
return 0;
}
@@ -7498,28 +7514,52 @@ static int bpf_object__resolve_externs(struct bpf_object *obj,
for (i = 0; i < obj->nr_extern; i++) {
ext = &obj->externs[i];
- if (ext->type == EXT_KCFG &&
- strcmp(ext->name, "LINUX_KERNEL_VERSION") == 0) {
- void *ext_val = kcfg_data + ext->kcfg.data_off;
- __u32 kver = get_kernel_version();
+ if (ext->type == EXT_KSYM) {
+ if (ext->ksym.type_id)
+ need_vmlinux_btf = true;
+ else
+ need_kallsyms = true;
+ continue;
+ } else if (ext->type == EXT_KCFG) {
+ void *ext_ptr = kcfg_data + ext->kcfg.data_off;
+ __u64 value = 0;
- if (!kver) {
- pr_warn("failed to get kernel version\n");
+ /* Kconfig externs need actual /proc/config.gz */
+ if (str_has_pfx(ext->name, "CONFIG_")) {
+ need_config = true;
+ continue;
+ }
+
+ /* Virtual kcfg externs are customly handled by libbpf */
+ if (strcmp(ext->name, "LINUX_KERNEL_VERSION") == 0) {
+ value = get_kernel_version();
+ if (!value) {
+ pr_warn("extern (kcfg) '%s': failed to get kernel version\n", ext->name);
+ return -EINVAL;
+ }
+ } else if (strcmp(ext->name, "LINUX_HAS_BPF_COOKIE") == 0) {
+ value = kernel_supports(obj, FEAT_BPF_COOKIE);
+ } else if (strcmp(ext->name, "LINUX_HAS_SYSCALL_WRAPPER") == 0) {
+ value = kernel_supports(obj, FEAT_SYSCALL_WRAPPER);
+ } else if (!str_has_pfx(ext->name, "LINUX_") || !ext->is_weak) {
+ /* Currently libbpf supports only CONFIG_ and LINUX_ prefixed
+ * __kconfig externs, where LINUX_ ones are virtual and filled out
+ * customly by libbpf (their values don't come from Kconfig).
+ * If LINUX_xxx variable is not recognized by libbpf, but is marked
+ * __weak, it defaults to zero value, just like for CONFIG_xxx
+ * externs.
+ */
+ pr_warn("extern (kcfg) '%s': unrecognized virtual extern\n", ext->name);
return -EINVAL;
}
- err = set_kcfg_value_num(ext, ext_val, kver);
+
+ err = set_kcfg_value_num(ext, ext_ptr, value);
if (err)
return err;
- pr_debug("extern (kcfg) %s=0x%x\n", ext->name, kver);
- } else if (ext->type == EXT_KCFG && str_has_pfx(ext->name, "CONFIG_")) {
- need_config = true;
- } else if (ext->type == EXT_KSYM) {
- if (ext->ksym.type_id)
- need_vmlinux_btf = true;
- else
- need_kallsyms = true;
+ pr_debug("extern (kcfg) '%s': set to 0x%llx\n",
+ ext->name, (long long)value);
} else {
- pr_warn("unrecognized extern '%s'\n", ext->name);
+ pr_warn("extern '%s': unrecognized extern kind\n", ext->name);
return -EINVAL;
}
}
@@ -7555,10 +7595,10 @@ static int bpf_object__resolve_externs(struct bpf_object *obj,
ext = &obj->externs[i];
if (!ext->is_set && !ext->is_weak) {
- pr_warn("extern %s (strong) not resolved\n", ext->name);
+ pr_warn("extern '%s' (strong): not resolved\n", ext->name);
return -ESRCH;
} else if (!ext->is_set) {
- pr_debug("extern %s (weak) not resolved, defaulting to zero\n",
+ pr_debug("extern '%s' (weak): not resolved, defaulting to zero\n",
ext->name);
}
}
@@ -8386,6 +8426,7 @@ int bpf_program__set_log_buf(struct bpf_program *prog, char *log_buf, size_t log
static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link);
static int attach_uprobe(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_ksyscall(const struct bpf_program *prog, long cookie, struct bpf_link **link);
static int attach_usdt(const struct bpf_program *prog, long cookie, struct bpf_link **link);
static int attach_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link);
static int attach_raw_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link);
@@ -8406,6 +8447,8 @@ static const struct bpf_sec_def section_defs[] = {
SEC_DEF("uretprobe.s+", KPROBE, 0, SEC_SLEEPABLE, attach_uprobe),
SEC_DEF("kprobe.multi+", KPROBE, BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi),
SEC_DEF("kretprobe.multi+", KPROBE, BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi),
+ SEC_DEF("ksyscall+", KPROBE, 0, SEC_NONE, attach_ksyscall),
+ SEC_DEF("kretsyscall+", KPROBE, 0, SEC_NONE, attach_ksyscall),
SEC_DEF("usdt+", KPROBE, 0, SEC_NONE, attach_usdt),
SEC_DEF("tc", SCHED_CLS, 0, SEC_NONE),
SEC_DEF("classifier", SCHED_CLS, 0, SEC_NONE),
@@ -9762,7 +9805,7 @@ static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
{
struct perf_event_attr attr = {};
char errmsg[STRERR_BUFSIZE];
- int type, pfd, err;
+ int type, pfd;
if (ref_ctr_off >= (1ULL << PERF_UPROBE_REF_CTR_OFFSET_BITS))
return -EINVAL;
@@ -9798,14 +9841,7 @@ static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
pid < 0 ? -1 : pid /* pid */,
pid == -1 ? 0 : -1 /* cpu */,
-1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
- if (pfd < 0) {
- err = -errno;
- pr_warn("%s perf_event_open() failed: %s\n",
- uprobe ? "uprobe" : "kprobe",
- libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
- return err;
- }
- return pfd;
+ return pfd >= 0 ? pfd : -errno;
}
static int append_to_file(const char *file, const char *fmt, ...)
@@ -9910,6 +9946,60 @@ err_clean_legacy:
return err;
}
+static const char *arch_specific_syscall_pfx(void)
+{
+#if defined(__x86_64__)
+ return "x64";
+#elif defined(__i386__)
+ return "ia32";
+#elif defined(__s390x__)
+ return "s390x";
+#elif defined(__s390__)
+ return "s390";
+#elif defined(__arm__)
+ return "arm";
+#elif defined(__aarch64__)
+ return "arm64";
+#elif defined(__mips__)
+ return "mips";
+#elif defined(__riscv)
+ return "riscv";
+#else
+ return NULL;
+#endif
+}
+
+static int probe_kern_syscall_wrapper(void)
+{
+ char syscall_name[64];
+ const char *ksys_pfx;
+
+ ksys_pfx = arch_specific_syscall_pfx();
+ if (!ksys_pfx)
+ return 0;
+
+ snprintf(syscall_name, sizeof(syscall_name), "__%s_sys_bpf", ksys_pfx);
+
+ if (determine_kprobe_perf_type() >= 0) {
+ int pfd;
+
+ pfd = perf_event_open_probe(false, false, syscall_name, 0, getpid(), 0);
+ if (pfd >= 0)
+ close(pfd);
+
+ return pfd >= 0 ? 1 : 0;
+ } else { /* legacy mode */
+ char probe_name[128];
+
+ gen_kprobe_legacy_event_name(probe_name, sizeof(probe_name), syscall_name, 0);
+ if (add_kprobe_event_legacy(probe_name, false, syscall_name, 0) < 0)
+ return 0;
+
+ (void)remove_kprobe_event_legacy(probe_name, false);
+ return 1;
+ }
+}
+
struct bpf_link *
bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
const char *func_name,
@@ -9995,6 +10085,29 @@ struct bpf_link *bpf_program__attach_kprobe(const struct bpf_program *prog,
return bpf_program__attach_kprobe_opts(prog, func_name, &opts);
}
+struct bpf_link *bpf_program__attach_ksyscall(const struct bpf_program *prog,
+ const char *syscall_name,
+ const struct bpf_ksyscall_opts *opts)
+{
+ LIBBPF_OPTS(bpf_kprobe_opts, kprobe_opts);
+ char func_name[128];
+
+ if (!OPTS_VALID(opts, bpf_ksyscall_opts))
+ return libbpf_err_ptr(-EINVAL);
+
+ if (kernel_supports(prog->obj, FEAT_SYSCALL_WRAPPER)) {
+ snprintf(func_name, sizeof(func_name), "__%s_sys_%s",
+ arch_specific_syscall_pfx(), syscall_name);
+ } else {
+ snprintf(func_name, sizeof(func_name), "__se_sys_%s", syscall_name);
+ }
+
+ kprobe_opts.retprobe = OPTS_GET(opts, retprobe, false);
+ kprobe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0);
+
+ return bpf_program__attach_kprobe_opts(prog, func_name, &kprobe_opts);
+}
+
/* Adapted from perf/util/string.c */
static bool glob_match(const char *str, const char *pat)
{
@@ -10165,6 +10278,27 @@ static int attach_kprobe(const struct bpf_program *prog, long cookie, struct bpf
return libbpf_get_error(*link);
}
+static int attach_ksyscall(const struct bpf_program *prog, long cookie, struct bpf_link **link)
+{
+ LIBBPF_OPTS(bpf_ksyscall_opts, opts);
+ const char *syscall_name;
+
+ *link = NULL;
+
+ /* no auto-attach for SEC("ksyscall") and SEC("kretsyscall") */
+ if (strcmp(prog->sec_name, "ksyscall") == 0 || strcmp(prog->sec_name, "kretsyscall") == 0)
+ return 0;
+
+ opts.retprobe = str_has_pfx(prog->sec_name, "kretsyscall/");
+ if (opts.retprobe)
+ syscall_name = prog->sec_name + sizeof("kretsyscall/") - 1;
+ else
+ syscall_name = prog->sec_name + sizeof("ksyscall/") - 1;
+
+ *link = bpf_program__attach_ksyscall(prog, syscall_name, &opts);
+ return *link ? 0 : -errno;
+}
+
static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link)
{
LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
generated by cgit v1.2.3 (git 2.46.0) at 2025-09-06 08:43:33 +0000