From 40b53b771806b1770837169cd32d1bf167fbccaf Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 25 Apr 2018 21:21:55 +0900 Subject: tracing: probeevent: Add array type support Add array type support for probe events. This allows user to get arraied types from memory address. The array type syntax is TYPE[N] Where TYPE is one of types (u8/16/32/64,s8/16/32/64, x8/16/32/64, symbol, string) and N is a fixed value less than 64. The string array type is a bit different from other types. For other base types, [1] is equal to (e.g. +0(%di):x32[1] is same as +0(%di):x32.) But string[1] is not equal to string. The string type itself represents "char array", but string array type represents "char * array". So, for example, +0(%di):string[1] is equal to +0(+0(%di)):string. Link: http://lkml.kernel.org/r/152465891533.26224.6150658225601339931.stgit@devbox Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_probe.c | 130 ++++++++++++++++++++++++++++++++++----------- 1 file changed, 99 insertions(+), 31 deletions(-) (limited to 'kernel/trace/trace_probe.c') diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 1e7e0618577d..dfd096031305 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -341,9 +341,9 @@ static int __parse_bitfield_probe_arg(const char *bf, int traceprobe_parse_probe_arg(char *arg, ssize_t *size, struct probe_arg *parg, bool is_return, bool is_kprobe) { - struct fetch_insn *code, *tmp = NULL; - const char *t; - int ret; + struct fetch_insn *code, *scode, *tmp = NULL; + char *t, *t2; + int ret, len; if (strlen(arg) > MAX_ARGSTR_LEN) { pr_info("Argument is too long.: %s\n", arg); @@ -354,24 +354,42 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size, pr_info("Failed to allocate memory for command '%s'.\n", arg); return -ENOMEM; } - t = strchr(parg->comm, ':'); + t = strchr(arg, ':'); if (t) { - arg[t - parg->comm] = '\0'; - t++; + *t = '\0'; + t2 = strchr(++t, '['); + if (t2) { + *t2 = '\0'; + parg->count = simple_strtoul(t2 + 1, &t2, 0); + if (strcmp(t2, "]") || parg->count == 0) + return -EINVAL; + if (parg->count > MAX_ARRAY_LEN) + return -E2BIG; + } } /* * The default type of $comm should be "string", and it can't be * dereferenced. */ if (!t && strcmp(arg, "$comm") == 0) - t = "string"; - parg->type = find_fetch_type(t); + parg->type = find_fetch_type("string"); + else + parg->type = find_fetch_type(t); if (!parg->type) { pr_info("Unsupported type: %s\n", t); return -EINVAL; } parg->offset = *size; - *size += parg->type->size; + *size += parg->type->size * (parg->count ?: 1); + + if (parg->count) { + len = strlen(parg->type->fmttype) + 6; + parg->fmt = kmalloc(len, GFP_KERNEL); + if (!parg->fmt) + return -ENOMEM; + snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype, + parg->count); + } code = tmp = kzalloc(sizeof(*code) * FETCH_INSN_MAX, GFP_KERNEL); if (!code) @@ -391,10 +409,20 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size, ret = -EINVAL; goto fail; } - /* Since IMM or COMM must be the 1st insn, this is safe */ - if (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM) + if (code->op != FETCH_OP_DEREF || parg->count) { + /* + * IMM and COMM is pointing actual address, those must + * be kept, and if parg->count != 0, this is an array + * of string pointers instead of string address itself. + */ code++; + if (code->op != FETCH_OP_NOP) { + ret = -E2BIG; + goto fail; + } + } code->op = FETCH_OP_ST_STRING; /* In DEREF case, replace it */ + code->size = parg->type->size; parg->dynamic = true; } else if (code->op == FETCH_OP_DEREF) { code->op = FETCH_OP_ST_MEM; @@ -408,12 +436,29 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size, code->op = FETCH_OP_ST_RAW; code->size = parg->type->size; } + scode = code; /* Modify operation */ if (t != NULL) { ret = __parse_bitfield_probe_arg(t, parg->type, &code); if (ret) goto fail; } + /* Loop(Array) operation */ + if (parg->count) { + if (scode->op != FETCH_OP_ST_MEM && + scode->op != FETCH_OP_ST_STRING) { + pr_info("array only accepts memory or address\n"); + ret = -EINVAL; + goto fail; + } + code++; + if (code->op != FETCH_OP_NOP) { + ret = -E2BIG; + goto fail; + } + code->op = FETCH_OP_LP_ARRAY; + code->param = parg->count; + } code++; code->op = FETCH_OP_END; @@ -452,14 +497,17 @@ void traceprobe_free_probe_arg(struct probe_arg *arg) kfree(arg->code); kfree(arg->name); kfree(arg->comm); + kfree(arg->fmt); } +/* When len=0, we just calculate the needed length */ +#define LEN_OR_ZERO (len ? len - pos : 0) static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, bool is_return) { - int i; + struct probe_arg *parg; + int i, j; int pos = 0; - const char *fmt, *arg; if (!is_return) { @@ -470,33 +518,49 @@ static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP; } - /* When len=0, we just calculate the needed length */ -#define LEN_OR_ZERO (len ? len - pos : 0) - pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt); for (i = 0; i < tp->nr_args; i++) { - pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s", - tp->args[i].name, tp->args[i].type->fmt); + parg = tp->args + i; + pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name); + if (parg->count) { + pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s", + parg->type->fmt); + for (j = 1; j < parg->count; j++) + pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s", + parg->type->fmt); + pos += snprintf(buf + pos, LEN_OR_ZERO, "}"); + } else + pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", + parg->type->fmt); } pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg); for (i = 0; i < tp->nr_args; i++) { - if (strcmp(tp->args[i].type->name, "string") == 0) + parg = tp->args + i; + if (parg->count) { + if (strcmp(parg->type->name, "string") == 0) + fmt = ", __get_str(%s[%d])"; + else + fmt = ", REC->%s[%d]"; + for (j = 0; j < parg->count; j++) + pos += snprintf(buf + pos, LEN_OR_ZERO, + fmt, parg->name, j); + } else { + if (strcmp(parg->type->name, "string") == 0) + fmt = ", __get_str(%s)"; + else + fmt = ", REC->%s"; pos += snprintf(buf + pos, LEN_OR_ZERO, - ", __get_str(%s)", - tp->args[i].name); - else - pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s", - tp->args[i].name); + fmt, parg->name); + } } -#undef LEN_OR_ZERO - /* return the length of print_fmt */ return pos; } +#undef LEN_OR_ZERO int traceprobe_set_print_fmt(struct trace_probe *tp, bool is_return) { @@ -524,11 +588,15 @@ int traceprobe_define_arg_fields(struct trace_event_call *event_call, /* Set argument names as fields */ for (i = 0; i < tp->nr_args; i++) { struct probe_arg *parg = &tp->args[i]; - - ret = trace_define_field(event_call, parg->type->fmttype, - parg->name, - offset + parg->offset, - parg->type->size, + const char *fmt = parg->type->fmttype; + int size = parg->type->size; + + if (parg->fmt) + fmt = parg->fmt; + if (parg->count) + size *= parg->count; + ret = trace_define_field(event_call, fmt, parg->name, + offset + parg->offset, size, parg->type->is_signed, FILTER_OTHER); if (ret) -- cgit v1.2.3