Merge branch 'perf/core' of...

Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux-2.6 into perf/core

Documentation/trace/kprobetrace.txt

@@ -42,7 +42,7 @@ Synopsis of kprobe_events
   +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
   NAME=FETCHARG : Set NAME as the argument name of FETCHARG.
   FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types
-		  (u8/u16/u32/u64/s8/s16/s32/s64) are supported.
+		  (u8/u16/u32/u64/s8/s16/s32/s64) and string are supported.
 
   (*) only for return probe.
   (**) this is useful for fetching a field of data structures.

tools/perf/Documentation/perf-probe.txt

@@ -94,8 +94,8 @@ Each probe argument follows below syntax.
 
  [NAME=]LOCALVAR|$retval|%REG|@SYMBOL[:TYPE]
 
-'NAME' specifies the name of this argument (optional). You can use the name of local variable, local data structure member (e.g. var->field, var.field2), or kprobe-tracer argument format (e.g. $retval, %ax, etc). Note that the name of this argument will be set as the last member name if you specify a local data structure member (e.g. field2 for 'var->field1.field2'.)
-'TYPE' casts the type of this argument (optional). If omitted, perf probe automatically set the type based on debuginfo.
+'NAME' specifies the name of this argument (optional). You can use the name of local variable, local data structure member (e.g. var->field, var.field2), local array with fixed index (e.g. array[1], var->array[0], var->pointer[2]), or kprobe-tracer argument format (e.g. $retval, %ax, etc). Note that the name of this argument will be set as the last member name if you specify a local data structure member (e.g. field2 for 'var->field1.field2'.)
+'TYPE' casts the type of this argument (optional). If omitted, perf probe automatically set the type based on debuginfo. You can specify 'string' type only for the local variable or structure member which is an array of or a pointer to 'char' or 'unsigned char' type.
 
 LINE SYNTAX
 -----------

tools/perf/Makefile

@@ -605,10 +605,11 @@ endif
 
 ifdef NO_DEMANGLE
 	BASIC_CFLAGS += -DNO_DEMANGLE
-else ifdef HAVE_CPLUS_DEMANGLE
+else
+        ifdef HAVE_CPLUS_DEMANGLE
 		EXTLIBS += -liberty
 		BASIC_CFLAGS += -DHAVE_CPLUS_DEMANGLE
-else
+        else
 		FLAGS_BFD=$(ALL_CFLAGS) $(ALL_LDFLAGS) $(EXTLIBS) -lbfd
 		has_bfd := $(call try-cc,$(SOURCE_BFD),$(FLAGS_BFD))
 		ifeq ($(has_bfd),y)
@@ -636,6 +637,7 @@ else
 				endif
 			endif
 		endif
+	endif
 endif
 
 ifndef CC_LD_DYNPATH

tools/perf/util/probe-event.c

@@ -557,7 +557,7 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 /* Parse perf-probe event argument */
 static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
 {
-	char *tmp;
+	char *tmp, *goodname;
 	struct perf_probe_arg_field **fieldp;
 
 	pr_debug("parsing arg: %s into ", str);
@@ -580,7 +580,7 @@ static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
 		pr_debug("type:%s ", arg->type);
 	}
 
-	tmp = strpbrk(str, "-.");
+	tmp = strpbrk(str, "-.[");
 	if (!is_c_varname(str) || !tmp) {
 		/* A variable, register, symbol or special value */
 		arg->var = strdup(str);
@@ -590,10 +590,11 @@ static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
 		return 0;
 	}
 
-	/* Structure fields */
+	/* Structure fields or array element */
 	arg->var = strndup(str, tmp - str);
 	if (arg->var == NULL)
 		return -ENOMEM;
+	goodname = arg->var;
 	pr_debug("%s, ", arg->var);
 	fieldp = &arg->field;
 
@@ -601,6 +602,19 @@ static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
 		*fieldp = zalloc(sizeof(struct perf_probe_arg_field));
 		if (*fieldp == NULL)
 			return -ENOMEM;
+		if (*tmp == '[') {	/* Array */
+			str = tmp;
+			(*fieldp)->index = strtol(str + 1, &tmp, 0);
+			(*fieldp)->ref = true;
+			if (*tmp != ']' || tmp == str + 1) {
+				semantic_error("Array index must be a"
+						" number.\n");
+				return -EINVAL;
+			}
+			tmp++;
+			if (*tmp == '\0')
+				tmp = NULL;
+		} else {		/* Structure */
 			if (*tmp == '.') {
 				str = tmp + 1;
 				(*fieldp)->ref = false;
@@ -608,15 +622,18 @@ static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
 				str = tmp + 2;
 				(*fieldp)->ref = true;
 			} else {
-			semantic_error("Argument parse error: %s\n", str);
+				semantic_error("Argument parse error: %s\n",
+					       str);
 				return -EINVAL;
 			}
-
-		tmp = strpbrk(str, "-.");
+			tmp = strpbrk(str, "-.[");
+		}
 		if (tmp) {
 			(*fieldp)->name = strndup(str, tmp - str);
 			if ((*fieldp)->name == NULL)
 				return -ENOMEM;
+			if (*str != '[')
+				goodname = (*fieldp)->name;
 			pr_debug("%s(%d), ", (*fieldp)->name, (*fieldp)->ref);
 			fieldp = &(*fieldp)->next;
 		}
@@ -624,11 +641,13 @@ static int parse_perf_probe_arg(char *str, struct perf_probe_arg *arg)
 	(*fieldp)->name = strdup(str);
 	if ((*fieldp)->name == NULL)
 		return -ENOMEM;
+	if (*str != '[')
+		goodname = (*fieldp)->name;
 	pr_debug("%s(%d)\n", (*fieldp)->name, (*fieldp)->ref);
 
-	/* If no name is specified, set the last field name */
+	/* If no name is specified, set the last field name (not array index)*/
 	if (!arg->name) {
-		arg->name = strdup((*fieldp)->name);
+		arg->name = strdup(goodname);
 		if (arg->name == NULL)
 			return -ENOMEM;
 	}
@@ -776,8 +795,11 @@ int synthesize_perf_probe_arg(struct perf_probe_arg *pa, char *buf, size_t len)
 	len -= ret;
 
 	while (field) {
-		ret = e_snprintf(tmp, len, "%s%s", field->ref ? "->" : ".",
-				 field->name);
+		if (field->name[0] == '[')
+			ret = e_snprintf(tmp, len, "%s", field->name);
+		else
+			ret = e_snprintf(tmp, len, "%s%s",
+					 field->ref ? "->" : ".", field->name);
 		if (ret <= 0)
 			goto error;
 		tmp += ret;
@@ -904,6 +926,7 @@ static int __synthesize_kprobe_trace_arg_ref(struct kprobe_trace_arg_ref *ref,
 static int synthesize_kprobe_trace_arg(struct kprobe_trace_arg *arg,
 				       char *buf, size_t buflen)
 {
+	struct kprobe_trace_arg_ref *ref = arg->ref;
 	int ret, depth = 0;
 	char *tmp = buf;
 
@@ -917,15 +940,23 @@ static int synthesize_kprobe_trace_arg(struct kprobe_trace_arg *arg,
 	buf += ret;
 	buflen -= ret;
 
+	/* Special case: @XXX */
+	if (arg->value[0] == '@' && arg->ref)
+			ref = ref->next;
+
 	/* Dereferencing arguments */
-	if (arg->ref) {
-		depth = __synthesize_kprobe_trace_arg_ref(arg->ref, &buf,
+	if (ref) {
+		depth = __synthesize_kprobe_trace_arg_ref(ref, &buf,
 							  &buflen, 1);
 		if (depth < 0)
 			return depth;
 	}
 
 	/* Print argument value */
+	if (arg->value[0] == '@' && arg->ref)
+		ret = e_snprintf(buf, buflen, "%s%+ld", arg->value,
+				 arg->ref->offset);
+	else
 		ret = e_snprintf(buf, buflen, "%s", arg->value);
 	if (ret < 0)
 		return ret;

tools/perf/util/probe-event.h

@@ -50,6 +50,7 @@ struct perf_probe_point {
 struct perf_probe_arg_field {
 	struct perf_probe_arg_field	*next;	/* Next field */
 	char				*name;	/* Name of the field */
+	long				index;	/* Array index number */
 	bool				ref;	/* Referencing flag */
 };
 

tools/perf/util/probe-finder.c

@@ -406,14 +406,50 @@ static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
  * Probe finder related functions
  */
 
+static struct kprobe_trace_arg_ref *alloc_trace_arg_ref(long offs)
+{
+	struct kprobe_trace_arg_ref *ref;
+	ref = zalloc(sizeof(struct kprobe_trace_arg_ref));
+	if (ref != NULL)
+		ref->offset = offs;
+	return ref;
+}
+
 /* Show a location */
-static int convert_location(Dwarf_Op *op, struct probe_finder *pf)
+static int convert_variable_location(Dwarf_Die *vr_die, struct probe_finder *pf)
 {
+	Dwarf_Attribute attr;
+	Dwarf_Op *op;
+	size_t nops;
 	unsigned int regn;
 	Dwarf_Word offs = 0;
 	bool ref = false;
 	const char *regs;
 	struct kprobe_trace_arg *tvar = pf->tvar;
+	int ret;
+
+	/* TODO: handle more than 1 exprs */
+	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL ||
+	    dwarf_getlocation_addr(&attr, pf->addr, &op, &nops, 1) <= 0 ||
+	    nops == 0) {
+		/* TODO: Support const_value */
+		pr_err("Failed to find the location of %s at this address.\n"
+		       " Perhaps, it has been optimized out.\n", pf->pvar->var);
+		return -ENOENT;
+	}
+
+	if (op->atom == DW_OP_addr) {
+		/* Static variables on memory (not stack), make @varname */
+		ret = strlen(dwarf_diename(vr_die));
+		tvar->value = zalloc(ret + 2);
+		if (tvar->value == NULL)
+			return -ENOMEM;
+		snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
+		tvar->ref = alloc_trace_arg_ref((long)offs);
+		if (tvar->ref == NULL)
+			return -ENOMEM;
+		return 0;
+	}
 
 	/* If this is based on frame buffer, set the offset */
 	if (op->atom == DW_OP_fbreg) {
@@ -455,27 +491,72 @@ static int convert_location(Dwarf_Op *op, struct probe_finder *pf)
 		return -ENOMEM;
 
 	if (ref) {
-		tvar->ref = zalloc(sizeof(struct kprobe_trace_arg_ref));
+		tvar->ref = alloc_trace_arg_ref((long)offs);
 		if (tvar->ref == NULL)
 			return -ENOMEM;
-		tvar->ref->offset = (long)offs;
 	}
 	return 0;
 }
 
 static int convert_variable_type(Dwarf_Die *vr_die,
-				 struct kprobe_trace_arg *targ)
+				 struct kprobe_trace_arg *tvar,
+				 const char *cast)
 {
+	struct kprobe_trace_arg_ref **ref_ptr = &tvar->ref;
 	Dwarf_Die type;
 	char buf[16];
 	int ret;
 
+	/* TODO: check all types */
+	if (cast && strcmp(cast, "string") != 0) {
+		/* Non string type is OK */
+		tvar->type = strdup(cast);
+		return (tvar->type == NULL) ? -ENOMEM : 0;
+	}
+
 	if (die_get_real_type(vr_die, &type) == NULL) {
 		pr_warning("Failed to get a type information of %s.\n",
 			   dwarf_diename(vr_die));
 		return -ENOENT;
 	}
 
+	pr_debug("%s type is %s.\n",
+		 dwarf_diename(vr_die), dwarf_diename(&type));
+
+	if (cast && strcmp(cast, "string") == 0) {	/* String type */
+		ret = dwarf_tag(&type);
+		if (ret != DW_TAG_pointer_type &&
+		    ret != DW_TAG_array_type) {
+			pr_warning("Failed to cast into string: "
+				   "%s(%s) is not a pointer nor array.",
+				   dwarf_diename(vr_die), dwarf_diename(&type));
+			return -EINVAL;
+		}
+		if (ret == DW_TAG_pointer_type) {
+			if (die_get_real_type(&type, &type) == NULL) {
+				pr_warning("Failed to get a type information.");
+				return -ENOENT;
+			}
+			while (*ref_ptr)
+				ref_ptr = &(*ref_ptr)->next;
+			/* Add new reference with offset +0 */
+			*ref_ptr = zalloc(sizeof(struct kprobe_trace_arg_ref));
+			if (*ref_ptr == NULL) {
+				pr_warning("Out of memory error\n");
+				return -ENOMEM;
+			}
+		}
+		if (die_compare_name(&type, "char") != 0 &&
+		    die_compare_name(&type, "unsigned char") != 0) {
+			pr_warning("Failed to cast into string: "
+				   "%s is not (unsigned) char *.",
+				   dwarf_diename(vr_die));
+			return -EINVAL;
+		}
+		tvar->type = strdup(cast);
+		return (tvar->type == NULL) ? -ENOMEM : 0;
+	}
+
 	ret = die_get_byte_size(&type) * 8;
 	if (ret) {
 		/* Check the bitwidth */
@@ -495,8 +576,8 @@ static int convert_variable_type(Dwarf_Die *vr_die,
 				   strerror(-ret));
 			return ret;
 		}
-		targ->type = strdup(buf);
-		if (targ->type == NULL)
+		tvar->type = strdup(buf);
+		if (tvar->type == NULL)
 			return -ENOMEM;
 	}
 	return 0;
@@ -510,16 +591,44 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 	struct kprobe_trace_arg_ref *ref = *ref_ptr;
 	Dwarf_Die type;
 	Dwarf_Word offs;
-	int ret;
+	int ret, tag;
 
 	pr_debug("converting %s in %s\n", field->name, varname);
 	if (die_get_real_type(vr_die, &type) == NULL) {
 		pr_warning("Failed to get the type of %s.\n", varname);
 		return -ENOENT;
 	}
+	pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
+	tag = dwarf_tag(&type);
 
+	if (field->name[0] == '[' &&
+	    (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
+		if (field->next)
+			/* Save original type for next field */
+			memcpy(die_mem, &type, sizeof(*die_mem));
+		/* Get the type of this array */
+		if (die_get_real_type(&type, &type) == NULL) {
+			pr_warning("Failed to get the type of %s.\n", varname);
+			return -ENOENT;
+		}
+		pr_debug2("Array real type: (%x)\n",
+			 (unsigned)dwarf_dieoffset(&type));
+		if (tag == DW_TAG_pointer_type) {
+			ref = zalloc(sizeof(struct kprobe_trace_arg_ref));
+			if (ref == NULL)
+				return -ENOMEM;
+			if (*ref_ptr)
+				(*ref_ptr)->next = ref;
+			else
+				*ref_ptr = ref;
+		}
+		ref->offset += die_get_byte_size(&type) * field->index;
+		if (!field->next)
+			/* Save vr_die for converting types */
+			memcpy(die_mem, vr_die, sizeof(*die_mem));
+		goto next;
+	} else if (tag == DW_TAG_pointer_type) {
 		/* Check the pointer and dereference */
-	if (dwarf_tag(&type) == DW_TAG_pointer_type) {
 		if (!field->ref) {
 			pr_err("Semantic error: %s must be referred by '->'\n",
 			       field->name);
@@ -545,10 +654,15 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 			*ref_ptr = ref;
 	} else {
 		/* Verify it is a data structure  */
-		if (dwarf_tag(&type) != DW_TAG_structure_type) {
+		if (tag != DW_TAG_structure_type) {
 			pr_warning("%s is not a data structure.\n", varname);
 			return -EINVAL;
 		}
+		if (field->name[0] == '[') {
+			pr_err("Semantic error: %s is not a pointor nor array.",
+			       varname);
+			return -EINVAL;
+		}
 		if (field->ref) {
 			pr_err("Semantic error: %s must be referred by '.'\n",
 			       field->name);
@@ -575,6 +689,7 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 	}
 	ref->offset += (long)offs;
 
+next:
 	/* Converting next field */
 	if (field->next)
 		return convert_variable_fields(die_mem, field->name,
@@ -586,51 +701,32 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 /* Show a variables in kprobe event format */
 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 {
-	Dwarf_Attribute attr;
 	Dwarf_Die die_mem;
-	Dwarf_Op *expr;
-	size_t nexpr;
 	int ret;
 
-	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
-		goto error;
-	/* TODO: handle more than 1 exprs */
-	ret = dwarf_getlocation_addr(&attr, pf->addr, &expr, &nexpr, 1);
-	if (ret <= 0 || nexpr == 0)
-		goto error;
+	pr_debug("Converting variable %s into trace event.\n",
+		 dwarf_diename(vr_die));
 
-	ret = convert_location(expr, pf);
+	ret = convert_variable_location(vr_die, pf);
 	if (ret == 0 && pf->pvar->field) {
 		ret = convert_variable_fields(vr_die, pf->pvar->var,
 					      pf->pvar->field, &pf->tvar->ref,
 					      &die_mem);
 		vr_die = &die_mem;
 	}
-	if (ret == 0) {
-		if (pf->pvar->type) {
-			pf->tvar->type = strdup(pf->pvar->type);
-			if (pf->tvar->type == NULL)
-				ret = -ENOMEM;
-		} else
-			ret = convert_variable_type(vr_die, pf->tvar);
-	}
+	if (ret == 0)
+		ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
 	/* *expr will be cached in libdw. Don't free it. */
 	return ret;
-error:
-	/* TODO: Support const_value */
-	pr_err("Failed to find the location of %s at this address.\n"
-	       " Perhaps, it has been optimized out.\n", pf->pvar->var);
-	return -ENOENT;
 }
 
 /* Find a variable in a subprogram die */
 static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 {
-	Dwarf_Die vr_die;
+	Dwarf_Die vr_die, *scopes;
 	char buf[32], *ptr;
-	int ret;
+	int ret, nscopes;
 
-	/* TODO: Support arrays */
 	if (pf->pvar->name)
 		pf->tvar->name = strdup(pf->pvar->name);
 	else {
@@ -657,12 +753,26 @@ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 	pr_debug("Searching '%s' variable in context.\n",
 		 pf->pvar->var);
 	/* Search child die for local variables and parameters. */
-	if (!die_find_variable(sp_die, pf->pvar->var, &vr_die)) {
+	if (die_find_variable(sp_die, pf->pvar->var, &vr_die))
+		ret = convert_variable(&vr_die, pf);
+	else {
+		/* Search upper class */
+		nscopes = dwarf_getscopes_die(sp_die, &scopes);
+		if (nscopes > 0) {
+			ret = dwarf_getscopevar(scopes, nscopes, pf->pvar->var,
+						0, NULL, 0, 0, &vr_die);
+			if (ret >= 0)
+				ret = convert_variable(&vr_die, pf);
+			else
+				ret = -ENOENT;
+			free(scopes);
+		} else
+			ret = -ENOENT;
+	}
+	if (ret < 0)
 		pr_warning("Failed to find '%s' in this function.\n",
 			   pf->pvar->var);
-		return -ENOENT;
-	}
-	return convert_variable(&vr_die, pf);
+	return ret;
 }
 
 /* Show a probe point to output buffer */