diff options
Diffstat (limited to 'tools/testing/selftests/bpf/trace_helpers.c')
-rw-r--r-- | tools/testing/selftests/bpf/trace_helpers.c | 328 |
1 files changed, 300 insertions, 28 deletions
diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c index 4d0e913bbb22..27fd7ed3e4b0 100644 --- a/tools/testing/selftests/bpf/trace_helpers.c +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -1,4 +1,5 @@ // SPDX-License-Identifier: GPL-2.0 +#include <ctype.h> #include <stdio.h> #include <stdlib.h> #include <string.h> @@ -6,95 +7,208 @@ #include <errno.h> #include <fcntl.h> #include <poll.h> +#include <pthread.h> #include <unistd.h> #include <linux/perf_event.h> #include <sys/mman.h> #include "trace_helpers.h" +#include <linux/limits.h> +#include <libelf.h> +#include <gelf.h> +#include "bpf/libbpf_internal.h" -#define DEBUGFS "/sys/kernel/debug/tracing/" +#define TRACEFS_PIPE "/sys/kernel/tracing/trace_pipe" +#define DEBUGFS_PIPE "/sys/kernel/debug/tracing/trace_pipe" -#define MAX_SYMS 300000 -static struct ksym syms[MAX_SYMS]; -static int sym_cnt; +struct ksyms { + struct ksym *syms; + size_t sym_cap; + size_t sym_cnt; +}; + +static struct ksyms *ksyms; +static pthread_mutex_t ksyms_mutex = PTHREAD_MUTEX_INITIALIZER; + +static int ksyms__add_symbol(struct ksyms *ksyms, const char *name, + unsigned long addr) +{ + void *tmp; + + tmp = strdup(name); + if (!tmp) + return -ENOMEM; + ksyms->syms[ksyms->sym_cnt].addr = addr; + ksyms->syms[ksyms->sym_cnt].name = tmp; + ksyms->sym_cnt++; + return 0; +} + +void free_kallsyms_local(struct ksyms *ksyms) +{ + unsigned int i; + + if (!ksyms) + return; + + if (!ksyms->syms) { + free(ksyms); + return; + } + + for (i = 0; i < ksyms->sym_cnt; i++) + free(ksyms->syms[i].name); + free(ksyms->syms); + free(ksyms); +} static int ksym_cmp(const void *p1, const void *p2) { return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr; } -int load_kallsyms(void) +struct ksyms *load_kallsyms_local(void) { - FILE *f = fopen("/proc/kallsyms", "r"); + FILE *f; char func[256], buf[256]; char symbol; void *addr; - int i = 0; + int ret; + struct ksyms *ksyms; + f = fopen("/proc/kallsyms", "r"); if (!f) - return -ENOENT; + return NULL; + + ksyms = calloc(1, sizeof(struct ksyms)); + if (!ksyms) { + fclose(f); + return NULL; + } while (fgets(buf, sizeof(buf), f)) { if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3) break; if (!addr) continue; - syms[i].addr = (long) addr; - syms[i].name = strdup(func); - i++; + + ret = libbpf_ensure_mem((void **) &ksyms->syms, &ksyms->sym_cap, + sizeof(struct ksym), ksyms->sym_cnt + 1); + if (ret) + goto error; + ret = ksyms__add_symbol(ksyms, func, (unsigned long)addr); + if (ret) + goto error; } fclose(f); - sym_cnt = i; - qsort(syms, sym_cnt, sizeof(struct ksym), ksym_cmp); - return 0; + qsort(ksyms->syms, ksyms->sym_cnt, sizeof(struct ksym), ksym_cmp); + return ksyms; + +error: + fclose(f); + free_kallsyms_local(ksyms); + return NULL; } -struct ksym *ksym_search(long key) +int load_kallsyms(void) +{ + pthread_mutex_lock(&ksyms_mutex); + if (!ksyms) + ksyms = load_kallsyms_local(); + pthread_mutex_unlock(&ksyms_mutex); + return ksyms ? 0 : 1; +} + +struct ksym *ksym_search_local(struct ksyms *ksyms, long key) { - int start = 0, end = sym_cnt; + int start = 0, end = ksyms->sym_cnt; int result; /* kallsyms not loaded. return NULL */ - if (sym_cnt <= 0) + if (ksyms->sym_cnt <= 0) return NULL; while (start < end) { size_t mid = start + (end - start) / 2; - result = key - syms[mid].addr; + result = key - ksyms->syms[mid].addr; if (result < 0) end = mid; else if (result > 0) start = mid + 1; else - return &syms[mid]; + return &ksyms->syms[mid]; } - if (start >= 1 && syms[start - 1].addr < key && - key < syms[start].addr) + if (start >= 1 && ksyms->syms[start - 1].addr < key && + key < ksyms->syms[start].addr) /* valid ksym */ - return &syms[start - 1]; + return &ksyms->syms[start - 1]; /* out of range. return _stext */ - return &syms[0]; + return &ksyms->syms[0]; } -long ksym_get_addr(const char *name) +struct ksym *ksym_search(long key) +{ + if (!ksyms) + return NULL; + return ksym_search_local(ksyms, key); +} + +long ksym_get_addr_local(struct ksyms *ksyms, const char *name) { int i; - for (i = 0; i < sym_cnt; i++) { - if (strcmp(syms[i].name, name) == 0) - return syms[i].addr; + for (i = 0; i < ksyms->sym_cnt; i++) { + if (strcmp(ksyms->syms[i].name, name) == 0) + return ksyms->syms[i].addr; } return 0; } +long ksym_get_addr(const char *name) +{ + if (!ksyms) + return 0; + return ksym_get_addr_local(ksyms, name); +} + +/* open kallsyms and read symbol addresses on the fly. Without caching all symbols, + * this is faster than load + find. + */ +int kallsyms_find(const char *sym, unsigned long long *addr) +{ + char type, name[500]; + unsigned long long value; + int err = 0; + FILE *f; + + f = fopen("/proc/kallsyms", "r"); + if (!f) + return -EINVAL; + + while (fscanf(f, "%llx %c %499s%*[^\n]\n", &value, &type, name) > 0) { + if (strcmp(name, sym) == 0) { + *addr = value; + goto out; + } + } + err = -ENOENT; + +out: + fclose(f); + return err; +} + void read_trace_pipe(void) { int trace_fd; - trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0); + if (access(TRACEFS_PIPE, F_OK) == 0) + trace_fd = open(TRACEFS_PIPE, O_RDONLY, 0); + else + trace_fd = open(DEBUGFS_PIPE, O_RDONLY, 0); if (trace_fd < 0) return; @@ -109,3 +223,161 @@ void read_trace_pipe(void) } } } + +ssize_t get_uprobe_offset(const void *addr) +{ + size_t start, end, base; + char buf[256]; + bool found = false; + FILE *f; + + f = fopen("/proc/self/maps", "r"); + if (!f) + return -errno; + + while (fscanf(f, "%zx-%zx %s %zx %*[^\n]\n", &start, &end, buf, &base) == 4) { + if (buf[2] == 'x' && (uintptr_t)addr >= start && (uintptr_t)addr < end) { + found = true; + break; + } + } + + fclose(f); + + if (!found) + return -ESRCH; + +#if defined(__powerpc64__) && defined(_CALL_ELF) && _CALL_ELF == 2 + +#define OP_RT_RA_MASK 0xffff0000UL +#define LIS_R2 0x3c400000UL +#define ADDIS_R2_R12 0x3c4c0000UL +#define ADDI_R2_R2 0x38420000UL + + /* + * A PPC64 ABIv2 function may have a local and a global entry + * point. We need to use the local entry point when patching + * functions, so identify and step over the global entry point + * sequence. + * + * The global entry point sequence is always of the form: + * + * addis r2,r12,XXXX + * addi r2,r2,XXXX + * + * A linker optimisation may convert the addis to lis: + * + * lis r2,XXXX + * addi r2,r2,XXXX + */ + { + const __u32 *insn = (const __u32 *)(uintptr_t)addr; + + if ((((*insn & OP_RT_RA_MASK) == ADDIS_R2_R12) || + ((*insn & OP_RT_RA_MASK) == LIS_R2)) && + ((*(insn + 1) & OP_RT_RA_MASK) == ADDI_R2_R2)) + return (uintptr_t)(insn + 2) - start + base; + } +#endif + return (uintptr_t)addr - start + base; +} + +ssize_t get_rel_offset(uintptr_t addr) +{ + size_t start, end, offset; + char buf[256]; + FILE *f; + + f = fopen("/proc/self/maps", "r"); + if (!f) + return -errno; + + while (fscanf(f, "%zx-%zx %s %zx %*[^\n]\n", &start, &end, buf, &offset) == 4) { + if (addr >= start && addr < end) { + fclose(f); + return (size_t)addr - start + offset; + } + } + + fclose(f); + return -EINVAL; +} + +static int +parse_build_id_buf(const void *note_start, Elf32_Word note_size, char *build_id) +{ + Elf32_Word note_offs = 0; + + while (note_offs + sizeof(Elf32_Nhdr) < note_size) { + Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs); + + if (nhdr->n_type == 3 && nhdr->n_namesz == sizeof("GNU") && + !strcmp((char *)(nhdr + 1), "GNU") && nhdr->n_descsz > 0 && + nhdr->n_descsz <= BPF_BUILD_ID_SIZE) { + memcpy(build_id, note_start + note_offs + + ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr), nhdr->n_descsz); + memset(build_id + nhdr->n_descsz, 0, BPF_BUILD_ID_SIZE - nhdr->n_descsz); + return (int) nhdr->n_descsz; + } + + note_offs = note_offs + sizeof(Elf32_Nhdr) + + ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4); + } + + return -ENOENT; +} + +/* Reads binary from *path* file and returns it in the *build_id* buffer + * with *size* which is expected to be at least BPF_BUILD_ID_SIZE bytes. + * Returns size of build id on success. On error the error value is + * returned. + */ +int read_build_id(const char *path, char *build_id, size_t size) +{ + int fd, err = -EINVAL; + Elf *elf = NULL; + GElf_Ehdr ehdr; + size_t max, i; + + if (size < BPF_BUILD_ID_SIZE) + return -EINVAL; + + fd = open(path, O_RDONLY | O_CLOEXEC); + if (fd < 0) + return -errno; + + (void)elf_version(EV_CURRENT); + + elf = elf_begin(fd, ELF_C_READ_MMAP, NULL); + if (!elf) + goto out; + if (elf_kind(elf) != ELF_K_ELF) + goto out; + if (!gelf_getehdr(elf, &ehdr)) + goto out; + + for (i = 0; i < ehdr.e_phnum; i++) { + GElf_Phdr mem, *phdr; + char *data; + + phdr = gelf_getphdr(elf, i, &mem); + if (!phdr) + goto out; + if (phdr->p_type != PT_NOTE) + continue; + data = elf_rawfile(elf, &max); + if (!data) + goto out; + if (phdr->p_offset + phdr->p_memsz > max) + goto out; + err = parse_build_id_buf(data + phdr->p_offset, phdr->p_memsz, build_id); + if (err > 0) + break; + } + +out: + if (elf) + elf_end(elf); + close(fd); + return err; +} |