diff options
| -rw-r--r-- | tools/perf/Makefile | 10 | ||||
| -rw-r--r-- | tools/perf/builtin-probe.c | 358 | ||||
| -rw-r--r-- | tools/perf/builtin.h | 1 | ||||
| -rw-r--r-- | tools/perf/perf.c | 3 | ||||
| -rw-r--r-- | tools/perf/util/probe-finder.c | 690 | ||||
| -rw-r--r-- | tools/perf/util/probe-finder.h | 68 |
6 files changed, 1130 insertions, 0 deletions
diff --git a/tools/perf/Makefile b/tools/perf/Makefile index b5f1953..6dabcf1 100644 --- a/tools/perf/Makefile +++ b/tools/perf/Makefile @@ -419,6 +419,16 @@ ifneq ($(shell sh -c "(echo '\#include <libelf.h>'; echo 'int main(void) { Elf * msg := $(error No libelf.h/libelf found, please install libelf-dev/elfutils-libelf-devel); endif +ifneq ($(shell sh -c "(echo '\#include <libdwarf/dwarf.h>'; echo '\#include <libdwarf/libdwarf.h>'; echo 'int main(void) { Dwarf_Debug dbg; Dwarf_Error err; dwarf_init(0, DW_DLC_READ, 0, 0, &dbg, &err); return (long)dbg; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -ldwarf -lelf -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y) + msg := $(warning No libdwarf.h found, disables probe subcommand. Please install libdwarf-dev/libdwarf-devel); +else + EXTLIBS += -lelf -ldwarf + LIB_H += util/probe-finder.h + LIB_OBJS += util/probe-finder.o + BUILTIN_OBJS += builtin-probe.o + BASIC_CFLAGS += -DSUPPORT_DWARF +endif + ifdef NO_DEMANGLE BASIC_CFLAGS += -DNO_DEMANGLE else diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c new file mode 100644 index 0000000..24b64b5 --- /dev/null +++ b/tools/perf/builtin-probe.c @@ -0,0 +1,358 @@ +/* + * builtin-probe.c + * + * Builtin probe command: Set up probe events by C expression + * + * Written by Masami Hiramatsu <mhiramat@redhat.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + */ +#define _GNU_SOURCE +#include <sys/utsname.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <errno.h> +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include <string.h> + +#undef _GNU_SOURCE +#include "perf.h" +#include "builtin.h" +#include "util/util.h" +#include "util/parse-options.h" +#include "util/parse-events.h" /* For debugfs_path */ +#include "util/probe-finder.h" + +/* Default vmlinux search paths */ +#define NR_SEARCH_PATH 3 +const char *default_search_path[NR_SEARCH_PATH] = { +"/lib/modules/%s/build/vmlinux", /* Custom build kernel */ +"/usr/lib/debug/lib/modules/%s/vmlinux", /* Red Hat debuginfo */ +"/boot/vmlinux-debug-%s", /* Ubuntu */ +}; + +#define MAX_PATH_LEN 256 +#define MAX_PROBES 128 + +/* Session management structure */ +static struct { + char *vmlinux; + char *release; + int nr_probe; + struct probe_point probes[MAX_PROBES]; + char *events[MAX_PROBES]; +} session; + +static void semantic_error(const char *msg) +{ + fprintf(stderr, "Semantic error: %s\n", msg); + exit(1); +} + +static void perror_exit(const char *msg) +{ + perror(msg); + exit(1); +} + +#define MAX_PROBE_ARGS 128 + +static int parse_probepoint(const struct option *opt __used, + const char *str, int unset __used) +{ + char *argv[MAX_PROBE_ARGS + 2]; /* Event + probe + args */ + int argc, i; + char *arg, *ptr; + struct probe_point *pp = &session.probes[session.nr_probe]; + char **event = &session.events[session.nr_probe]; + int retp = 0; + + if (!str) /* The end of probe points */ + return 0; + + debug("Probe-define(%d): %s\n", session.nr_probe, str); + if (++session.nr_probe == MAX_PROBES) + semantic_error("Too many probes"); + + /* Separate arguments, similar to argv_split */ + argc = 0; + do { + /* Skip separators */ + while (isspace(*str)) + str++; + + /* Add an argument */ + if (*str != '\0') { + const char *s = str; + + /* Skip the argument */ + while (!isspace(*str) && *str != '\0') + str++; + + /* Duplicate the argument */ + argv[argc] = strndup(s, str - s); + if (argv[argc] == NULL) + perror_exit("strndup"); + if (++argc == MAX_PROBE_ARGS) + semantic_error("Too many arguments"); + debug("argv[%d]=%s\n", argc, argv[argc - 1]); + } + } while (*str != '\0'); + if (argc < 2) + semantic_error("Need event-name and probe-point at least."); + + /* Parse the event name */ + if (argv[0][0] == 'r') + retp = 1; + else if (argv[0][0] != 'p') + semantic_error("You must specify 'p'(kprobe) or" + " 'r'(kretprobe) first."); + /* TODO: check event name */ + *event = argv[0]; + + /* Parse probe point */ + arg = argv[1]; + if (arg[0] == '@') { + /* Source Line */ + arg++; + ptr = strchr(arg, ':'); + if (!ptr || !isdigit(ptr[1])) + semantic_error("Line number is required."); + *ptr++ = '\0'; + if (strlen(arg) == 0) + semantic_error("No file name."); + pp->file = strdup(arg); + pp->line = atoi(ptr); + if (!pp->file || !pp->line) + semantic_error("Failed to parse line."); + debug("file:%s line:%d\n", pp->file, pp->line); + } else { + /* Function name */ + ptr = strchr(arg, '+'); + if (ptr) { + if (!isdigit(ptr[1])) + semantic_error("Offset is required."); + *ptr++ = '\0'; + pp->offset = atoi(ptr); + } else + ptr = arg; + ptr = strchr(ptr, '@'); + if (ptr) { + *ptr++ = '\0'; + pp->file = strdup(ptr); + } + pp->function = strdup(arg); + debug("symbol:%s file:%s offset:%d\n", + pp->function, pp->file, pp->offset); + } + free(argv[1]); + + /* Copy arguments */ + pp->nr_args = argc - 2; + if (pp->nr_args > 0) { + pp->args = (char **)malloc(sizeof(char *) * pp->nr_args); + if (!pp->args) + perror_exit("malloc"); + memcpy(pp->args, &argv[2], sizeof(char *) * pp->nr_args); + } + + /* Ensure return probe has no C argument */ + if (retp) + for (i = 0; i < pp->nr_args; i++) + if (is_c_varname(pp->args[i])) + semantic_error("You can't specify local" + " variable for kretprobe"); + debug("%d arguments\n", pp->nr_args); + return 0; +} + +static int open_default_vmlinux(void) +{ + struct utsname uts; + char fname[MAX_PATH_LEN]; + int fd, ret, i; + + ret = uname(&uts); + if (ret) { + debug("uname() failed.\n"); + return -errno; + } + session.release = uts.release; + for (i = 0; i < NR_SEARCH_PATH; i++) { + ret = snprintf(fname, MAX_PATH_LEN, + default_search_path[i], session.release); + if (ret >= MAX_PATH_LEN || ret < 0) { + debug("Filename(%d,%s) is too long.\n", i, uts.release); + errno = E2BIG; + return -E2BIG; + } + debug("try to open %s\n", fname); + fd = open(fname, O_RDONLY); + if (fd >= 0) + break; + } + return fd; +} + +static const char * const probe_usage[] = { + "perf probe [<options>] -P 'PROBEDEF' [-P 'PROBEDEF' ...]", + NULL +}; + +static const struct option options[] = { + OPT_STRING('k', "vmlinux", &session.vmlinux, "file", + "vmlinux/module pathname"), + OPT_CALLBACK('P', "probe", NULL, + "p|r:[GRP/]NAME FUNC[+OFFS][@SRC]|@SRC:LINE [ARG ...]", + "probe point definition, where\n" + "\t\tp:\tkprobe probe\n" + "\t\tr:\tkretprobe probe\n" + "\t\tGRP:\tGroup name (optional)\n" + "\t\tNAME:\tEvent name\n" + "\t\tFUNC:\tFunction name\n" + "\t\tOFFS:\tOffset from function entry (in byte)\n" + "\t\tSRC:\tSource code path\n" + "\t\tLINE:\tLine number\n" + "\t\tARG:\tProbe argument (local variable name or\n" + "\t\t\tkprobe-tracer argument format is supported.)\n", + parse_probepoint), + OPT_END() +}; + +static int write_new_event(int fd, const char *buf) +{ + int ret; + + printf("Adding new event: %s\n", buf); + ret = write(fd, buf, strlen(buf)); + if (ret <= 0) + perror("Error: Failed to create event"); + + return ret; +} + +#define MAX_CMDLEN 256 + +static int synthesize_probepoint(struct probe_point *pp) +{ + char *buf; + int i, len, ret; + pp->probes[0] = buf = (char *)calloc(MAX_CMDLEN, sizeof(char)); + if (!buf) + perror_exit("calloc"); + ret = snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset); + if (ret <= 0 || ret >= MAX_CMDLEN) + goto error; + len = ret; + + for (i = 0; i < pp->nr_args; i++) { + ret = snprintf(&buf[len], MAX_CMDLEN - len, " %s", + pp->args[i]); + if (ret <= 0 || ret >= MAX_CMDLEN - len) + goto error; + len += ret; + } + pp->found = 1; + return pp->found; +error: + free(pp->probes[0]); + if (ret > 0) + ret = -E2BIG; + return ret; +} + +int cmd_probe(int argc, const char **argv, const char *prefix __used) +{ + int i, j, fd, ret, need_dwarf = 0; + struct probe_point *pp; + char buf[MAX_CMDLEN]; + + argc = parse_options(argc, argv, options, probe_usage, + PARSE_OPT_STOP_AT_NON_OPTION); + if (argc || session.nr_probe == 0) + usage_with_options(probe_usage, options); + + /* Synthesize return probes */ + for (j = 0; j < session.nr_probe; j++) { + if (session.events[j][0] != 'r') { + need_dwarf = 1; + continue; + } + ret = synthesize_probepoint(&session.probes[j]); + if (ret == -E2BIG) + semantic_error("probe point is too long."); + else if (ret < 0) { + perror("snprintf"); + return -1; + } + } + + if (!need_dwarf) + goto setup_probes; + + if (session.vmlinux) + fd = open(session.vmlinux, O_RDONLY); + else + fd = open_default_vmlinux(); + if (fd < 0) { + perror("vmlinux/module file open"); + return -1; + } + + /* Searching probe points */ + for (j = 0; j < session.nr_probe; j++) { + pp = &session.probes[j]; + if (pp->found) + continue; + + lseek(fd, SEEK_SET, 0); + ret = find_probepoint(fd, pp); + if (ret <= 0) { + fprintf(stderr, "Error: No probe point found.\n"); + return -1; + } + debug("probe event %s found\n", session.events[j]); + } + close(fd); + +setup_probes: + /* Settng up probe points */ + snprintf(buf, MAX_CMDLEN, "%s/../kprobe_events", debugfs_path); + fd = open(buf, O_WRONLY, O_APPEND); + if (fd < 0) { + perror("kprobe_events open"); + return -1; + } + for (j = 0; j < session.nr_probe; j++) { + pp = &session.probes[j]; + if (pp->found == 1) { + snprintf(buf, MAX_CMDLEN, "%s %s\n", + session.events[j], pp->probes[0]); + write_new_event(fd, buf); + } else + for (i = 0; i < pp->found; i++) { + snprintf(buf, MAX_CMDLEN, "%s%d %s\n", + session.events[j], i, pp->probes[i]); + write_new_event(fd, buf); + } + } + close(fd); + return 0; +} + diff --git a/tools/perf/builtin.h b/tools/perf/builtin.h index e11d8d2..ad5f0f4 100644 --- a/tools/perf/builtin.h +++ b/tools/perf/builtin.h @@ -25,5 +25,6 @@ extern int cmd_timechart(int argc, const char **argv, const char *prefix); extern int cmd_top(int argc, const char **argv, const char *prefix); extern int cmd_trace(int argc, const char **argv, const char *prefix); extern int cmd_version(int argc, const char **argv, const char *prefix); +extern int cmd_probe(int argc, const char **argv, const char *prefix); #endif diff --git a/tools/perf/perf.c b/tools/perf/perf.c index 19fc7fe..f598120 100644 --- a/tools/perf/perf.c +++ b/tools/perf/perf.c @@ -295,6 +295,9 @@ static void handle_internal_command(int argc, const char **argv) { "version", cmd_version, 0 }, { "trace", cmd_trace, 0 }, { "sched", cmd_sched, 0 }, +#ifdef SUPPORT_DWARF + { "probe", cmd_probe, 0 }, +#endif }; unsigned int i; static const char ext[] = STRIP_EXTENSION; diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c new file mode 100644 index 0000000..ec6f53f --- /dev/null +++ b/tools/perf/util/probe-finder.c @@ -0,0 +1,690 @@ +/* + * probe-finder.c : C expression to kprobe event converter + * + * Written by Masami Hiramatsu <mhiramat@redhat.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + */ + +#include <sys/utsname.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <errno.h> +#include <stdio.h> +#include <unistd.h> +#include <getopt.h> +#include <stdlib.h> +#include <string.h> +#include <stdarg.h> +#include <ctype.h> +#include "probe-finder.h" + + +/* Dwarf_Die Linkage to parent Die */ +struct die_link { + struct die_link *parent; /* Parent die */ + Dwarf_Die die; /* Current die */ +}; + +static Dwarf_Debug __dw_debug; +static Dwarf_Error __dw_error; + +static void msg_exit(int ret, const char *fmt, ...) +{ + va_list ap; + + va_start(ap, fmt); + fprintf(stderr, "Error: "); + vfprintf(stderr, fmt, ap); + va_end(ap); + + fprintf(stderr, "\n"); + exit(ret); +} + + +/* + * Generic dwarf analysis helpers + */ + +#define X86_32_MAX_REGS 8 +const char *x86_32_regs_table[X86_32_MAX_REGS] = { + "%ax", + "%cx", + "%dx", + "%bx", + "$stack", /* Stack address instead of %sp */ + "%bp", + "%si", + "%di", +}; + +#define X86_64_MAX_REGS 16 +const char *x86_64_regs_table[X86_64_MAX_REGS] = { + "%ax", + "%dx", + "%cx", + "%bx", + "%si", + "%di", + "%bp", + "%sp", + "%r8", + "%r9", + "%r10", + "%r11", + "%r12", + "%r13", + "%r14", + "%r15", +}; + +/* TODO: switching by dwarf address size */ +#ifdef __x86_64__ +#define ARCH_MAX_REGS X86_64_MAX_REGS +#define arch_regs_table x86_64_regs_table +#else +#define ARCH_MAX_REGS X86_32_MAX_REGS +#define arch_regs_table x86_32_regs_table +#endif + +/* Return architecture dependent register string (for kprobe-tracer) */ +static const char *get_arch_regstr(unsigned int n) +{ + return (n <= ARCH_MAX_REGS) ? arch_regs_table[n] : NULL; +} + +/* + * Compare the tail of two strings. + * Return 0 if whole of either string is same as another's tail part. + */ +static int strtailcmp(const char *s1, const char *s2) +{ + int i1 = strlen(s1); + int i2 = strlen(s2); + while (--i1 > 0 && --i2 > 0) { + if (s1[i1] != s2[i2]) + return s1[i1] - s2[i2]; + } + return 0; +} + +/* Find the fileno of the target file. */ +static Dwarf_Unsigned die_get_fileno(Dwarf_Die cu_die, const char *fname) +{ + Dwarf_Signed cnt, i; + Dwarf_Unsigned found = 0; + char **srcs; + int ret; + + if (!fname) + return 0; + + ret = dwarf_srcfiles(cu_die, &srcs, &cnt, &__dw_error); + if (ret == DW_DLV_OK) { + for (i = 0; i < cnt && !found; i++) { + if (strtailcmp(srcs[i], fname) == 0) + found = i + 1; + dwarf_dealloc(__dw_debug, srcs[i], DW_DLA_STRING); + } + for (; i < cnt; i++) + dwarf_dealloc(__dw_debug, srcs[i], DW_DLA_STRING); + dwarf_dealloc(__dw_debug, srcs, DW_DLA_LIST); + } + if (found) + debug("found fno: %d\n", (int)found); + return found; +} + +/* Compare diename and tname */ +static int die_compare_name(Dwarf_Die die, const char *tname) +{ + char *name; + int ret; + ret = dwarf_diename(die, &name, &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_OK) { + ret = strcmp(tname, name); + dwarf_dealloc(__dw_debug, name, DW_DLA_STRING); + } else + ret = -1; + return ret; +} + +/* Check the address is in the subprogram(function). */ +static int die_within_subprogram(Dwarf_Die sp_die, Dwarf_Addr addr, + Dwarf_Signed *offs) +{ + Dwarf_Addr lopc, hipc; + int ret; + + /* TODO: check ranges */ + ret = dwarf_lowpc(sp_die, &lopc, &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_NO_ENTRY) + return 0; + ret = dwarf_highpc(sp_die, &hipc, &__dw_error); + ERR_IF(ret != DW_DLV_OK); + if (lopc <= addr && addr < hipc) { + *offs = addr - lopc; + return 1; + } else + return 0; +} + +/* Check the die is inlined function */ +static Dwarf_Bool die_inlined_subprogram(Dwarf_Die die) +{ + /* TODO: check strictly */ + Dwarf_Bool inl; + int ret; + + ret = dwarf_hasattr(die, DW_AT_inline, &inl, &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + return inl; +} + +/* Get the offset of abstruct_origin */ +static Dwarf_Off die_get_abstract_origin(Dwarf_Die die) +{ + Dwarf_Attribute attr; + Dwarf_Off cu_offs; + int ret; + + ret = dwarf_attr(die, DW_AT_abstract_origin, &attr, &__dw_error); + ERR_IF(ret != DW_DLV_OK); + ret = dwarf_formref(attr, &cu_offs, &__dw_error); + ERR_IF(ret != DW_DLV_OK); + dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR); + return cu_offs; +} + +/* Get entry pc(or low pc, 1st entry of ranges) of the die */ +static Dwarf_Addr die_get_entrypc(Dwarf_Die die) +{ + Dwarf_Attribute attr; + Dwarf_Addr addr; + Dwarf_Off offs; + Dwarf_Ranges *ranges; + Dwarf_Signed cnt; + int ret; + + /* Try to get entry pc */ + ret = dwarf_attr(die, DW_AT_entry_pc, &attr, &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_OK) { + ret = dwarf_formaddr(attr, &addr, &__dw_error); + ERR_IF(ret != DW_DLV_OK); + dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR); + return addr; + } + + /* Try to get low pc */ + ret = dwarf_lowpc(die, &addr, &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_OK) + return addr; + + /* Try to get ranges */ + ret = dwarf_attr(die, DW_AT_ranges, &attr, &__dw_error); + ERR_IF(ret != DW_DLV_OK); + ret = dwarf_formref(attr, &offs, &__dw_error); + ERR_IF(ret != DW_DLV_OK); + ret = dwarf_get_ranges(__dw_debug, offs, &ranges, &cnt, NULL, + &__dw_error); + ERR_IF(ret != DW_DLV_OK); + addr = ranges[0].dwr_addr1; + dwarf_ranges_dealloc(__dw_debug, ranges, cnt); + return addr; +} + +/* + * Search a Die from Die tree. + * Note: cur_link->die should be deallocated in this function. + */ +static int __search_die_tree(struct die_link *cur_link, + int (*die_cb)(struct die_link *, void *), + void *data) +{ + Dwarf_Die new_die; + struct die_link new_link; + int ret; + + if (!die_cb) + return 0; + + /* Check current die */ + while (!(ret = die_cb(cur_link, data))) { + /* Check child die */ + ret = dwarf_child(cur_link->die, &new_die, &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_OK) { + new_link.parent = cur_link; + new_link.die = new_die; + ret = __search_die_tree(&new_link, die_cb, data); + if (ret) + break; + } + + /* Move to next sibling */ + ret = dwarf_siblingof(__dw_debug, cur_link->die, &new_die, + &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + dwarf_dealloc(__dw_debug, cur_link->die, DW_DLA_DIE); + cur_link->die = new_die; + if (ret == DW_DLV_NO_ENTRY) + return 0; + } + dwarf_dealloc(__dw_debug, cur_link->die, DW_DLA_DIE); + return ret; +} + +/* Search a die in its children's die tree */ +static int search_die_from_children(Dwarf_Die parent_die, + int (*die_cb)(struct die_link *, void *), + void *data) +{ + struct die_link new_link; + int ret; + + new_link.parent = NULL; + ret = dwarf_child(parent_die, &new_link.die, &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_OK) + return __search_die_tree(&new_link, die_cb, data); + else + return 0; +} + +/* Find a locdesc corresponding to the address */ +static int attr_get_locdesc(Dwarf_Attribute attr, Dwarf_Locdesc *desc, + Dwarf_Addr addr) +{ + Dwarf_Signed lcnt; + Dwarf_Locdesc **llbuf; + int ret, i; + + ret = dwarf_loclist_n(attr, &llbuf, &lcnt, &__dw_error); + ERR_IF(ret != DW_DLV_OK); + ret = DW_DLV_NO_ENTRY; + for (i = 0; i < lcnt; ++i) { + if (llbuf[i]->ld_lopc <= addr && + llbuf[i]->ld_hipc > addr) { + memcpy(desc, llbuf[i], sizeof(Dwarf_Locdesc)); + desc->ld_s = + malloc(sizeof(Dwarf_Loc) * llbuf[i]->ld_cents); + ERR_IF(desc->ld_s == NULL); + memcpy(desc->ld_s, llbuf[i]->ld_s, + sizeof(Dwarf_Loc) * llbuf[i]->ld_cents); + ret = DW_DLV_OK; + break; + } + dwarf_dealloc(__dw_debug, llbuf[i]->ld_s, DW_DLA_LOC_BLOCK); + dwarf_dealloc(__dw_debug, llbuf[i], DW_DLA_LOCDESC); + } + /* Releasing loop */ + for (; i < lcnt; ++i) { + dwarf_dealloc(__dw_debug, llbuf[i]->ld_s, DW_DLA_LOC_BLOCK); + dwarf_dealloc(__dw_debug, llbuf[i], DW_DLA_LOCDESC); + } + dwarf_dealloc(__dw_debug, llbuf, DW_DLA_LIST); + return ret; +} + +/* + * Probe finder related functions + */ + +/* Show a location */ +static void show_location(Dwarf_Loc *loc, struct probe_finder *pf) +{ + Dwarf_Small op; + Dwarf_Unsigned regn; + Dwarf_Signed offs; + int deref = 0, ret; + const char *regs; + + op = loc->lr_atom; + + /* If this is based on frame buffer, set the offset */ + if (op == DW_OP_fbreg) { + deref = 1; + offs = (Dwarf_Signed)loc->lr_number; + op = pf->fbloc.ld_s[0].lr_atom; + loc = &pf->fbloc.ld_s[0]; + } else + offs = 0; + + if (op >= DW_OP_breg0 && op <= DW_OP_breg31) { + regn = op - DW_OP_breg0; + offs += (Dwarf_Signed)loc->lr_number; + deref = 1; + } else if (op >= DW_OP_reg0 && op <= DW_OP_reg31) { + regn = op - DW_OP_reg0; + } else if (op == DW_OP_bregx) { + regn = loc->lr_number; + offs += (Dwarf_Signed)loc->lr_number2; + deref = 1; + } else if (op == DW_OP_regx) { + regn = loc->lr_number; + } else + msg_exit(-EINVAL, "Dwarf_OP %d is not supported.\n", op); + + regs = get_arch_regstr(regn); + if (!regs) + msg_exit(-EINVAL, "%lld exceeds max register number.\n", regn); + + if (deref) + ret = snprintf(pf->buf, pf->len, + " %s=%+lld(%s)", pf->var, offs, regs); + else + ret = snprintf(pf->buf, pf->len, " %s=%s", pf->var, regs); + ERR_IF(ret < 0); + ERR_IF(ret >= pf->len); +} + +/* Show a variables in kprobe event format */ +static void show_variable(Dwarf_Die vr_die, struct probe_finder *pf) +{ + Dwarf_Attribute attr; + Dwarf_Locdesc ld; + int ret; + + ret = dwarf_attr(vr_die, DW_AT_location, &attr, &__dw_error); + if (ret != DW_DLV_OK) + goto error; + ret = attr_get_locdesc(attr, &ld, (pf->addr - pf->cu_base)); + if (ret != DW_DLV_OK) + goto error; + /* TODO? */ + ERR_IF(ld.ld_cents != 1); + show_location(&ld.ld_s[0], pf); + free(ld.ld_s); + dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR); + return ; +error: + msg_exit(-1, "Failed to find the location of %s at this address.\n" + " Perhaps, it was optimized out.\n", pf->var); +} + +static int variable_callback(struct die_link *dlink, void *data) +{ + struct probe_finder *pf = (struct probe_finder *)data; + Dwarf_Half tag; + int ret; + + ret = dwarf_tag(dlink->die, &tag, &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + if ((tag == DW_TAG_formal_parameter || + tag == DW_TAG_variable) && + (die_compare_name(dlink->die, pf->var) == 0)) { + show_variable(dlink->die, pf); + return 1; + } + /* TODO: Support struct members and arrays */ + return 0; +} + +/* Find a variable in a subprogram die */ +static void find_variable(Dwarf_Die sp_die, struct probe_finder *pf) +{ + int ret; + + if (!is_c_varname(pf->var)) { + /* Output raw parameters */ + ret = snprintf(pf->buf, pf->len, " %s", pf->var); + ERR_IF(ret < 0); + ERR_IF(ret >= pf->len); + return ; + } + + debug("Searching '%s' variable in context.\n", pf->var); + /* Search child die for local variables and parameters. */ + ret = search_die_from_children(sp_die, variable_callback, pf); + if (!ret) + msg_exit(-1, "Failed to find '%s' in this function.\n", + pf->var); +} + +/* Get a frame base on the address */ +static void get_current_frame_base(Dwarf_Die sp_die, struct probe_finder *pf) +{ + Dwarf_Attribute attr; + int ret; + + ret = dwarf_attr(sp_die, DW_AT_frame_base, &attr, &__dw_error); + ERR_IF(ret != DW_DLV_OK); + ret = attr_get_locdesc(attr, &pf->fbloc, (pf->addr - pf->cu_base)); + ERR_IF(ret != DW_DLV_OK); + dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR); +} + +static void free_current_frame_base(struct probe_finder *pf) +{ + free(pf->fbloc.ld_s); + memset(&pf->fbloc, 0, sizeof(Dwarf_Locdesc)); +} + +/* Show a probe point to output buffer */ +static void show_probepoint(Dwarf_Die sp_die, Dwarf_Signed offs, + struct probe_finder *pf) +{ + struct probe_point *pp = pf->pp; + char *name; + char tmp[MAX_PROBE_BUFFER]; + int ret, i, len; + + /* Output name of probe point */ + ret = dwarf_diename(sp_die, &name, &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_OK) { + ret = snprintf(tmp, MAX_PROBE_BUFFER, "%s+%u", name, + (unsigned int)offs); + dwarf_dealloc(__dw_debug, name, DW_DLA_STRING); + } else { + /* This function has no name. */ + ret = snprintf(tmp, MAX_PROBE_BUFFER, "0x%llx", pf->addr); + } + ERR_IF(ret < 0); + ERR_IF(ret >= MAX_PROBE_BUFFER); + len = ret; + + /* Find each argument */ + get_current_frame_base(sp_die, pf); + for (i = 0; i < pp->nr_args; i++) { + pf->var = pp->args[i]; + pf->buf = &tmp[len]; + pf->len = MAX_PROBE_BUFFER - len; + find_variable(sp_die, pf); + len += strlen(pf->buf); + } + free_current_frame_base(pf); + + pp->probes[pp->found] = strdup(tmp); + pp->found++; +} + +static int probeaddr_callback(struct die_link *dlink, void *data) +{ + struct probe_finder *pf = (struct probe_finder *)data; + Dwarf_Half tag; + Dwarf_Signed offs; + int ret; + + ret = dwarf_tag(dlink->die, &tag, &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + /* Check the address is in this subprogram */ + if (tag == DW_TAG_subprogram && + die_within_subprogram(dlink->die, pf->addr, &offs)) { + show_probepoint(dlink->die, offs, pf); + return 1; + } + return 0; +} + +/* Find probe point from its line number */ +static void find_by_line(Dwarf_Die cu_die, struct probe_finder *pf) +{ + struct probe_point *pp = pf->pp; + Dwarf_Signed cnt, i; + Dwarf_Line *lines; + Dwarf_Unsigned lineno = 0; + Dwarf_Addr addr; + Dwarf_Unsigned fno; + int ret; + + ret = dwarf_srclines(cu_die, &lines, &cnt, &__dw_error); + ERR_IF(ret != DW_DLV_OK); + + for (i = 0; i < cnt; i++) { + ret = dwarf_line_srcfileno(lines[i], &fno, &__dw_error); + ERR_IF(ret != DW_DLV_OK); + if (fno != pf->fno) + continue; + + ret = dwarf_lineno(lines[i], &lineno, &__dw_error); + ERR_IF(ret != DW_DLV_OK); + if (lineno != (Dwarf_Unsigned)pp->line) + continue; + + ret = dwarf_lineaddr(lines[i], &addr, &__dw_error); + ERR_IF(ret != DW_DLV_OK); + debug("Probe point found: 0x%llx\n", addr); + pf->addr = addr; + /* Search a real subprogram including this line, */ + ret = search_die_from_children(cu_die, probeaddr_callback, pf); + if (ret == 0) + msg_exit(-1, + "Probe point is not found in subprograms.\n"); + /* Continuing, because target line might be inlined. */ + } + dwarf_srclines_dealloc(__dw_debug, lines, cnt); +} + +/* Search function from function name */ +static int probefunc_callback(struct die_link *dlink, void *data) +{ + struct probe_finder *pf = (struct probe_finder *)data; + struct probe_point *pp = pf->pp; + struct die_link *lk; + Dwarf_Signed offs; + Dwarf_Half tag; + int ret; + + ret = dwarf_tag(dlink->die, &tag, &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + if (tag == DW_TAG_subprogram) { + if (die_compare_name(dlink->die, pp->function) == 0) { + if (die_inlined_subprogram(dlink->die)) { + /* Inlined function, save it. */ + ret = dwarf_die_CU_offset(dlink->die, + &pf->inl_offs, + &__dw_error); + ERR_IF(ret != DW_DLV_OK); + debug("inline definition offset %lld\n", + pf->inl_offs); + return 0; + } + /* Get probe address */ + pf->addr = die_get_entrypc(dlink->die); + pf->addr += pp->offset; + /* TODO: Check the address in this function */ + show_probepoint(dlink->die, pp->offset, pf); + /* Continue to search */ + } + } else if (tag == DW_TAG_inlined_subroutine && pf->inl_offs) { + if (die_get_abstract_origin(dlink->die) == pf->inl_offs) { + /* Get probe address */ + pf->addr = die_get_entrypc(dlink->die); + pf->addr += pp->offset; + debug("found inline addr: 0x%llx\n", pf->addr); + /* Inlined function. Get a real subprogram */ + for (lk = dlink->parent; lk != NULL; lk = lk->parent) { + tag = 0; + dwarf_tag(lk->die, &tag, &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + if (tag == DW_TAG_subprogram && + !die_inlined_subprogram(lk->die)) + goto found; + } + msg_exit(-1, "Failed to find real subprogram.\n"); +found: + /* Get offset from subprogram */ + ret = die_within_subprogram(lk->die, pf->addr, &offs); + ERR_IF(!ret); + show_probepoint(lk->die, offs, pf); + /* Continue to search */ + } + } + return 0; +} + +static void find_by_func(Dwarf_Die cu_die, struct probe_finder *pf) +{ + search_die_from_children(cu_die, probefunc_callback, pf); +} + +/* Find a probe point */ +int find_probepoint(int fd, struct probe_point *pp) +{ + Dwarf_Half addr_size = 0; + Dwarf_Unsigned next_cuh = 0; + Dwarf_Die cu_die = 0; + int cu_number = 0, ret; + struct probe_finder pf = {.pp = pp}; + + ret = dwarf_init(fd, DW_DLC_READ, 0, 0, &__dw_debug, &__dw_error); + if (ret != DW_DLV_OK) + msg_exit(-1, "Failed to call dwarf_init(). " + "Maybe, not a dwarf file?\n"); + + pp->found = 0; + while (++cu_number) { + /* Search CU (Compilation Unit) */ + ret = dwarf_next_cu_header(__dw_debug, NULL, NULL, NULL, + &addr_size, &next_cuh, &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_NO_ENTRY) + break; + + /* Get the DIE(Debugging Information Entry) of this CU */ + ret = dwarf_siblingof(__dw_debug, 0, &cu_die, &__dw_error); + ERR_IF(ret != DW_DLV_OK); + + /* Check if target file is included. */ + if (pp->file) + pf.fno = die_get_fileno(cu_die, pp->file); + + if (!pp->file || pf.fno) { + /* Save CU base address (for frame_base) */ + ret = dwarf_lowpc(cu_die, &pf.cu_base, &__dw_error); + ERR_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_NO_ENTRY) + pf.cu_base = 0; + if (pp->line) + find_by_line(cu_die, &pf); + if (pp->function) + find_by_func(cu_die, &pf); + } + dwarf_dealloc(__dw_debug, cu_die, DW_DLA_DIE); + } + ret = dwarf_finish(__dw_debug, &__dw_error); + ERR_IF(ret != DW_DLV_OK); + + return pp->found; +} + diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h new file mode 100644 index 0000000..af920de --- /dev/null +++ b/tools/perf/util/probe-finder.h @@ -0,0 +1,68 @@ +#ifndef _PROBE_FINDER_H +#define _PROBE_FINDER_H + +#define _stringify(n) #n +#define stringify(n) _stringify(n) + +#ifdef DEBUG +#define debug(fmt ...) \ + fprintf(stderr, "DBG(" __FILE__ ":" stringify(__LINE__) "): " fmt) +#else +#define debug(fmt ...) do {} while (0) +#endif + +#define ERR_IF(cnd) \ + do { if (cnd) { \ + fprintf(stderr, "Error (" __FILE__ ":" stringify(__LINE__) \ + "): " stringify(cnd) "\n"); \ + exit(1); \ + } } while (0) + +#define MAX_PATH_LEN 256 +#define MAX_PROBE_BUFFER 1024 +#define MAX_PROBES 128 + +static inline int is_c_varname(const char *name) +{ + /* TODO */ + return isalpha(name[0]) || name[0] == '_'; +} + +struct probe_point { + /* Inputs */ + char *file; /* File name */ + int line; /* Line number */ + + char *function; /* Function name */ + int offset; /* Offset bytes */ + + int nr_args; /* Number of arguments */ + char **args; /* Arguments */ + + /* Output */ + int found; /* Number of found probe points */ + char *probes[MAX_PROBES]; /* Output buffers (will be allocated)*/ +}; + +extern int find_probepoint(int fd, struct probe_point *pp); + +#include <libdwarf/dwarf.h> +#include <libdwarf/libdwarf.h> + +struct probe_finder { + struct probe_point *pp; /* Target probe point */ + + /* For function searching */ + Dwarf_Addr addr; /* Address */ + Dwarf_Unsigned fno; /* File number */ + Dwarf_Off inl_offs; /* Inline offset */ + + /* For variable searching */ + Dwarf_Addr cu_base; /* Current CU base address */ + Dwarf_Locdesc fbloc; /* Location of Current Frame Base */ + const char *var; /* Current variable name */ + char *buf; /* Current output buffer */ + int len; /* Length of output buffer */ +}; + +#endif /*_PROBE_FINDER_H */ |
