diff options
| -rw-r--r-- | tools/lib/bpf/usdt.c | 123 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/Makefile | 14 |
2 files changed, 72 insertions, 65 deletions
diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c index f1c9339cfbbc..5159207cbfd9 100644 --- a/tools/lib/bpf/usdt.c +++ b/tools/lib/bpf/usdt.c @@ -441,7 +441,7 @@ static int parse_elf_segs(Elf *elf, const char *path, struct elf_seg **segs, siz return 0; } -static int parse_lib_segs(int pid, const char *lib_path, struct elf_seg **segs, size_t *seg_cnt) +static int parse_vma_segs(int pid, const char *lib_path, struct elf_seg **segs, size_t *seg_cnt) { char path[PATH_MAX], line[PATH_MAX], mode[16]; size_t seg_start, seg_end, seg_off; @@ -531,35 +531,40 @@ err_out: return err; } -static struct elf_seg *find_elf_seg(struct elf_seg *segs, size_t seg_cnt, long addr, bool relative) +static struct elf_seg *find_elf_seg(struct elf_seg *segs, size_t seg_cnt, long virtaddr) { struct elf_seg *seg; int i; - if (relative) { - /* for shared libraries, address is relative offset and thus - * should be fall within logical offset-based range of - * [offset_start, offset_end) - */ - for (i = 0, seg = segs; i < seg_cnt; i++, seg++) { - if (seg->offset <= addr && addr < seg->offset + (seg->end - seg->start)) - return seg; - } - } else { - /* for binaries, address is absolute and thus should be within - * absolute address range of [seg_start, seg_end) - */ - for (i = 0, seg = segs; i < seg_cnt; i++, seg++) { - if (seg->start <= addr && addr < seg->end) - return seg; - } + /* for ELF binaries (both executables and shared libraries), we are + * given virtual address (absolute for executables, relative for + * libraries) which should match address range of [seg_start, seg_end) + */ + for (i = 0, seg = segs; i < seg_cnt; i++, seg++) { + if (seg->start <= virtaddr && virtaddr < seg->end) + return seg; } + return NULL; +} +static struct elf_seg *find_vma_seg(struct elf_seg *segs, size_t seg_cnt, long offset) +{ + struct elf_seg *seg; + int i; + + /* for VMA segments from /proc/<pid>/maps file, provided "address" is + * actually a file offset, so should be fall within logical + * offset-based range of [offset_start, offset_end) + */ + for (i = 0, seg = segs; i < seg_cnt; i++, seg++) { + if (seg->offset <= offset && offset < seg->offset + (seg->end - seg->start)) + return seg; + } return NULL; } -static int parse_usdt_note(Elf *elf, const char *path, long base_addr, - GElf_Nhdr *nhdr, const char *data, size_t name_off, size_t desc_off, +static int parse_usdt_note(Elf *elf, const char *path, GElf_Nhdr *nhdr, + const char *data, size_t name_off, size_t desc_off, struct usdt_note *usdt_note); static int parse_usdt_spec(struct usdt_spec *spec, const struct usdt_note *note, __u64 usdt_cookie); @@ -568,8 +573,8 @@ static int collect_usdt_targets(struct usdt_manager *man, Elf *elf, const char * const char *usdt_provider, const char *usdt_name, __u64 usdt_cookie, struct usdt_target **out_targets, size_t *out_target_cnt) { - size_t off, name_off, desc_off, seg_cnt = 0, lib_seg_cnt = 0, target_cnt = 0; - struct elf_seg *segs = NULL, *lib_segs = NULL; + size_t off, name_off, desc_off, seg_cnt = 0, vma_seg_cnt = 0, target_cnt = 0; + struct elf_seg *segs = NULL, *vma_segs = NULL; struct usdt_target *targets = NULL, *target; long base_addr = 0; Elf_Scn *notes_scn, *base_scn; @@ -613,8 +618,7 @@ static int collect_usdt_targets(struct usdt_manager *man, Elf *elf, const char * struct elf_seg *seg = NULL; void *tmp; - err = parse_usdt_note(elf, path, base_addr, &nhdr, - data->d_buf, name_off, desc_off, ¬e); + err = parse_usdt_note(elf, path, &nhdr, data->d_buf, name_off, desc_off, ¬e); if (err) goto err_out; @@ -654,30 +658,29 @@ static int collect_usdt_targets(struct usdt_manager *man, Elf *elf, const char * usdt_rel_ip += base_addr - note.base_addr; } - if (ehdr.e_type == ET_EXEC) { - /* When attaching uprobes (which what USDTs basically - * are) kernel expects a relative IP to be specified, - * so if we are attaching to an executable ELF binary - * (i.e., not a shared library), we need to calculate - * proper relative IP based on ELF's load address - */ - seg = find_elf_seg(segs, seg_cnt, usdt_abs_ip, false /* relative */); - if (!seg) { - err = -ESRCH; - pr_warn("usdt: failed to find ELF program segment for '%s:%s' in '%s' at IP 0x%lx\n", - usdt_provider, usdt_name, path, usdt_abs_ip); - goto err_out; - } - if (!seg->is_exec) { - err = -ESRCH; - pr_warn("usdt: matched ELF binary '%s' segment [0x%lx, 0x%lx) for '%s:%s' at IP 0x%lx is not executable\n", - path, seg->start, seg->end, usdt_provider, usdt_name, - usdt_abs_ip); - goto err_out; - } + /* When attaching uprobes (which is what USDTs basically are) + * kernel expects file offset to be specified, not a relative + * virtual address, so we need to translate virtual address to + * file offset, for both ET_EXEC and ET_DYN binaries. + */ + seg = find_elf_seg(segs, seg_cnt, usdt_abs_ip); + if (!seg) { + err = -ESRCH; + pr_warn("usdt: failed to find ELF program segment for '%s:%s' in '%s' at IP 0x%lx\n", + usdt_provider, usdt_name, path, usdt_abs_ip); + goto err_out; + } + if (!seg->is_exec) { + err = -ESRCH; + pr_warn("usdt: matched ELF binary '%s' segment [0x%lx, 0x%lx) for '%s:%s' at IP 0x%lx is not executable\n", + path, seg->start, seg->end, usdt_provider, usdt_name, + usdt_abs_ip); + goto err_out; + } + /* translate from virtual address to file offset */ + usdt_rel_ip = usdt_abs_ip - seg->start + seg->offset; - usdt_rel_ip = usdt_abs_ip - (seg->start - seg->offset); - } else if (!man->has_bpf_cookie) { /* ehdr.e_type == ET_DYN */ + if (ehdr.e_type == ET_DYN && !man->has_bpf_cookie) { /* If we don't have BPF cookie support but need to * attach to a shared library, we'll need to know and * record absolute addresses of attach points due to @@ -697,9 +700,9 @@ static int collect_usdt_targets(struct usdt_manager *man, Elf *elf, const char * goto err_out; } - /* lib_segs are lazily initialized only if necessary */ - if (lib_seg_cnt == 0) { - err = parse_lib_segs(pid, path, &lib_segs, &lib_seg_cnt); + /* vma_segs are lazily initialized only if necessary */ + if (vma_seg_cnt == 0) { + err = parse_vma_segs(pid, path, &vma_segs, &vma_seg_cnt); if (err) { pr_warn("usdt: failed to get memory segments in PID %d for shared library '%s': %d\n", pid, path, err); @@ -707,7 +710,7 @@ static int collect_usdt_targets(struct usdt_manager *man, Elf *elf, const char * } } - seg = find_elf_seg(lib_segs, lib_seg_cnt, usdt_rel_ip, true /* relative */); + seg = find_vma_seg(vma_segs, vma_seg_cnt, usdt_rel_ip); if (!seg) { err = -ESRCH; pr_warn("usdt: failed to find shared lib memory segment for '%s:%s' in '%s' at relative IP 0x%lx\n", @@ -715,7 +718,7 @@ static int collect_usdt_targets(struct usdt_manager *man, Elf *elf, const char * goto err_out; } - usdt_abs_ip = seg->start + (usdt_rel_ip - seg->offset); + usdt_abs_ip = seg->start - seg->offset + usdt_rel_ip; } pr_debug("usdt: probe for '%s:%s' in %s '%s': addr 0x%lx base 0x%lx (resolved abs_ip 0x%lx rel_ip 0x%lx) args '%s' in segment [0x%lx, 0x%lx) at offset 0x%lx\n", @@ -723,7 +726,7 @@ static int collect_usdt_targets(struct usdt_manager *man, Elf *elf, const char * note.loc_addr, note.base_addr, usdt_abs_ip, usdt_rel_ip, note.args, seg ? seg->start : 0, seg ? seg->end : 0, seg ? seg->offset : 0); - /* Adjust semaphore address to be a relative offset */ + /* Adjust semaphore address to be a file offset */ if (note.sema_addr) { if (!man->has_sema_refcnt) { pr_warn("usdt: kernel doesn't support USDT semaphore refcounting for '%s:%s' in '%s'\n", @@ -732,7 +735,7 @@ static int collect_usdt_targets(struct usdt_manager *man, Elf *elf, const char * goto err_out; } - seg = find_elf_seg(segs, seg_cnt, note.sema_addr, false /* relative */); + seg = find_elf_seg(segs, seg_cnt, note.sema_addr); if (!seg) { err = -ESRCH; pr_warn("usdt: failed to find ELF loadable segment with semaphore of '%s:%s' in '%s' at 0x%lx\n", @@ -747,7 +750,7 @@ static int collect_usdt_targets(struct usdt_manager *man, Elf *elf, const char * goto err_out; } - usdt_sema_off = note.sema_addr - (seg->start - seg->offset); + usdt_sema_off = note.sema_addr - seg->start + seg->offset; pr_debug("usdt: sema for '%s:%s' in %s '%s': addr 0x%lx base 0x%lx (resolved 0x%lx) in segment [0x%lx, 0x%lx] at offset 0x%lx\n", usdt_provider, usdt_name, ehdr.e_type == ET_EXEC ? "exec" : "lib ", @@ -770,7 +773,7 @@ static int collect_usdt_targets(struct usdt_manager *man, Elf *elf, const char * target->rel_ip = usdt_rel_ip; target->sema_off = usdt_sema_off; - /* notes->args references strings from Elf itself, so they can + /* notes.args references strings from Elf itself, so they can * be referenced safely until elf_end() call */ target->spec_str = note.args; @@ -788,7 +791,7 @@ static int collect_usdt_targets(struct usdt_manager *man, Elf *elf, const char * err_out: free(segs); - free(lib_segs); + free(vma_segs); if (err < 0) free(targets); return err; @@ -1089,8 +1092,8 @@ err_out: /* Parse out USDT ELF note from '.note.stapsdt' section. * Logic inspired by perf's code. */ -static int parse_usdt_note(Elf *elf, const char *path, long base_addr, - GElf_Nhdr *nhdr, const char *data, size_t name_off, size_t desc_off, +static int parse_usdt_note(Elf *elf, const char *path, GElf_Nhdr *nhdr, + const char *data, size_t name_off, size_t desc_off, struct usdt_note *note) { const char *provider, *name, *args; diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 8ad7a733a505..e08e8e34e793 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -172,13 +172,15 @@ $(OUTPUT)/%:%.c # do not fail. Static builds leave urandom_read relying on system-wide shared libraries. $(OUTPUT)/liburandom_read.so: urandom_read_lib1.c urandom_read_lib2.c $(call msg,LIB,,$@) - $(Q)$(CC) $(filter-out -static,$(CFLAGS) $(LDFLAGS)) $^ $(LDLIBS) -fPIC -shared -o $@ + $(Q)$(CLANG) $(filter-out -static,$(CFLAGS) $(LDFLAGS)) $^ $(LDLIBS) \ + -fuse-ld=lld -Wl,-znoseparate-code -fPIC -shared -o $@ $(OUTPUT)/urandom_read: urandom_read.c urandom_read_aux.c $(OUTPUT)/liburandom_read.so $(call msg,BINARY,,$@) - $(Q)$(CC) $(filter-out -static,$(CFLAGS) $(LDFLAGS)) $(filter %.c,$^) \ - liburandom_read.so $(LDLIBS) \ - -Wl,-rpath=. -Wl,--build-id=sha1 -o $@ + $(Q)$(CLANG) $(filter-out -static,$(CFLAGS) $(LDFLAGS)) $(filter %.c,$^) \ + liburandom_read.so $(LDLIBS) \ + -fuse-ld=lld -Wl,-znoseparate-code \ + -Wl,-rpath=. -Wl,--build-id=sha1 -o $@ $(OUTPUT)/bpf_testmod.ko: $(VMLINUX_BTF) $(wildcard bpf_testmod/Makefile bpf_testmod/*.[ch]) $(call msg,MOD,,$@) @@ -580,6 +582,8 @@ $(OUTPUT)/bench: $(OUTPUT)/bench.o \ EXTRA_CLEAN := $(TEST_CUSTOM_PROGS) $(SCRATCH_DIR) $(HOST_SCRATCH_DIR) \ prog_tests/tests.h map_tests/tests.h verifier/tests.h \ feature bpftool \ - $(addprefix $(OUTPUT)/,*.o *.skel.h *.lskel.h *.subskel.h no_alu32 bpf_gcc bpf_testmod.ko) + $(addprefix $(OUTPUT)/,*.o *.skel.h *.lskel.h *.subskel.h \ + no_alu32 bpf_gcc bpf_testmod.ko \ + liburandom_read.so) .PHONY: docs docs-clean |