tools/perf/tests/vmlinux-kallsyms.c - maze/linux - Git at Google

 #include <linux/compiler.h>
 #include <linux/rbtree.h>
 #include <string.h>
 #include "map.h"
 #include "symbol.h"
 #include "util.h"
 #include "tests.h"
 #include "debug.h"
 #include "machine.h"

 static int vmlinux_matches_kallsyms_filter(struct map *map __maybe_unused,
 					   struct symbol *sym)
 {
 	bool *visited = symbol__priv(sym);
 	*visited = true;
 	return 0;
 }

 #define UM(x) kallsyms_map->unmap_ip(kallsyms_map, (x))

 int test__vmlinux_matches_kallsyms(void)
 {
 	int err = -1;
 	struct rb_node *nd;
 	struct symbol *sym;
 	struct map *kallsyms_map, *vmlinux_map;
 	struct machine kallsyms, vmlinux;
 	enum map_type type = MAP__FUNCTION;
 	u64 mem_start, mem_end;

 	/*
 	 * Step 1:
 	 *
 	 * Init the machines that will hold kernel, modules obtained from
 	 * both vmlinux + .ko files and from /proc/kallsyms split by modules.
 	 */
 	machine__init(&kallsyms, "", HOST_KERNEL_ID);
 	machine__init(&vmlinux, "", HOST_KERNEL_ID);

 	/*
 	 * Step 2:
 	 *
 	 * Create the kernel maps for kallsyms and the DSO where we will then
 	 * load /proc/kallsyms. Also create the modules maps from /proc/modules
 	 * and find the .ko files that match them in /lib/modules/`uname -r`/.
 	 */
 	if (machine__create_kernel_maps(&kallsyms) < 0) {
 		pr_debug("machine__create_kernel_maps ");
 		goto out;
 	}

 	/*
 	 * Step 3:
 	 *
 	 * Load and split /proc/kallsyms into multiple maps, one per module.
 	 */
 	if (machine__load_kallsyms(&kallsyms, "/proc/kallsyms", type, NULL) <= 0) {
 		pr_debug("dso__load_kallsyms ");
 		goto out;
 	}

 	/*
 	 * Step 4:
 	 *
 	 * kallsyms will be internally on demand sorted by name so that we can
 	 * find the reference relocation * symbol, i.e. the symbol we will use
 	 * to see if the running kernel was relocated by checking if it has the
 	 * same value in the vmlinux file we load.
 	 */
 	kallsyms_map = machine__kernel_map(&kallsyms, type);

 	/*
 	 * Step 5:
 	 *
 	 * Now repeat step 2, this time for the vmlinux file we'll auto-locate.
 	 */
 	if (machine__create_kernel_maps(&vmlinux) < 0) {
 		pr_debug("machine__create_kernel_maps ");
 		goto out;
 	}

 	vmlinux_map = machine__kernel_map(&vmlinux, type);

 	/*
 	 * Step 6:
 	 *
 	 * Locate a vmlinux file in the vmlinux path that has a buildid that
 	 * matches the one of the running kernel.
 	 *
 	 * While doing that look if we find the ref reloc symbol, if we find it
 	 * we'll have its ref_reloc_symbol.unrelocated_addr and then
 	 * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines
 	 * to fixup the symbols.
 	 */
 	if (machine__load_vmlinux_path(&vmlinux, type,
 				       vmlinux_matches_kallsyms_filter) <= 0) {
 		pr_debug("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n");
 		err = TEST_SKIP;
 		goto out;
 	}

 	err = 0;
 	/*
 	 * Step 7:
 	 *
 	 * Now look at the symbols in the vmlinux DSO and check if we find all of them
 	 * in the kallsyms dso. For the ones that are in both, check its names and
 	 * end addresses too.
 	 */
 	for (nd = rb_first(&vmlinux_map->dso->symbols[type]); nd; nd = rb_next(nd)) {
 		struct symbol *pair, *first_pair;
 		bool backwards = true;

 		sym  = rb_entry(nd, struct symbol, rb_node);

 		if (sym->start == sym->end)
 			continue;

 		mem_start = vmlinux_map->unmap_ip(vmlinux_map, sym->start);
 		mem_end = vmlinux_map->unmap_ip(vmlinux_map, sym->end);

 		first_pair = machine__find_kernel_symbol(&kallsyms, type,
 							 mem_start, NULL, NULL);
 		pair = first_pair;

 		if (pair && UM(pair->start) == mem_start) {
 next_pair:
 			if (strcmp(sym->name, pair->name) == 0) {
 				/*
 				 * kallsyms don't have the symbol end, so we
 				 * set that by using the next symbol start - 1,
 				 * in some cases we get this up to a page
 				 * wrong, trace_kmalloc when I was developing
 				 * this code was one such example, 2106 bytes
 				 * off the real size. More than that and we
 				 * _really_ have a problem.
 				 */
 				s64 skew = mem_end - UM(pair->end);
 				if (llabs(skew) >= page_size)
 					pr_debug("%#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n",
 						 mem_start, sym->name, mem_end,
 						 UM(pair->end));

 				/*
 				 * Do not count this as a failure, because we
 				 * could really find a case where it's not
 				 * possible to get proper function end from
 				 * kallsyms.
 				 */
 				continue;

 			} else {
 				struct rb_node *nnd;
 detour:
 				nnd = backwards ? rb_prev(&pair->rb_node) :
 						  rb_next(&pair->rb_node);
 				if (nnd) {
 					struct symbol *next = rb_entry(nnd, struct symbol, rb_node);

 					if (UM(next->start) == mem_start) {
 						pair = next;
 						goto next_pair;
 					}
 				}

 				if (backwards) {
 					backwards = false;
 					pair = first_pair;
 					goto detour;
 				}

 				pr_debug("%#" PRIx64 ": diff name v: %s k: %s\n",
 					 mem_start, sym->name, pair->name);
 			}
 		} else
 			pr_debug("%#" PRIx64 ": %s not on kallsyms\n",
 				 mem_start, sym->name);

 		err = -1;
 	}

 	if (!verbose)
 		goto out;

 	pr_info("Maps only in vmlinux:\n");

 	for (nd = rb_first(&vmlinux.kmaps.maps[type]); nd; nd = rb_next(nd)) {
 		struct map *pos = rb_entry(nd, struct map, rb_node), *pair;
 		/*
 		 * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while
 		 * the kernel will have the path for the vmlinux file being used,
 		 * so use the short name, less descriptive but the same ("[kernel]" in
 		 * both cases.
 		 */
 		pair = map_groups__find_by_name(&kallsyms.kmaps, type,
 						(pos->dso->kernel ?
 							pos->dso->short_name :
 							pos->dso->name));
 		if (pair)
 			pair->priv = 1;
 		else
 			map__fprintf(pos, stderr);
 	}

 	pr_info("Maps in vmlinux with a different name in kallsyms:\n");

 	for (nd = rb_first(&vmlinux.kmaps.maps[type]); nd; nd = rb_next(nd)) {
 		struct map *pos = rb_entry(nd, struct map, rb_node), *pair;

 		mem_start = vmlinux_map->unmap_ip(vmlinux_map, pos->start);
 		mem_end = vmlinux_map->unmap_ip(vmlinux_map, pos->end);

 		pair = map_groups__find(&kallsyms.kmaps, type, mem_start);
 		if (pair == NULL || pair->priv)
 			continue;

 		if (pair->start == mem_start) {
 			pair->priv = 1;
 			pr_info(" %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as",
 				pos->start, pos->end, pos->pgoff, pos->dso->name);
 			if (mem_end != pair->end)
 				pr_info(":\n*%" PRIx64 "-%" PRIx64 " %" PRIx64,
 					pair->start, pair->end, pair->pgoff);
 			pr_info(" %s\n", pair->dso->name);
 			pair->priv = 1;
 		}
 	}

 	pr_info("Maps only in kallsyms:\n");

 	for (nd = rb_first(&kallsyms.kmaps.maps[type]);
 	     nd; nd = rb_next(nd)) {
 		struct map *pos = rb_entry(nd, struct map, rb_node);

 		if (!pos->priv)
 			map__fprintf(pos, stderr);
 	}
 out:
 	machine__exit(&kallsyms);
 	machine__exit(&vmlinux);
 	return err;
 }
	#include <linux/compiler.h>
	#include <linux/rbtree.h>
	#include <string.h>
	#include "map.h"
	#include "symbol.h"
	#include "util.h"
	#include "tests.h"
	#include "debug.h"
	#include "machine.h"

	static int vmlinux_matches_kallsyms_filter(struct map *map __maybe_unused,
	struct symbol *sym)
	{
	bool *visited = symbol__priv(sym);
	*visited = true;
	return 0;
	}

	#define UM(x) kallsyms_map->unmap_ip(kallsyms_map, (x))

	int test__vmlinux_matches_kallsyms(void)
	{
	int err = -1;
	struct rb_node *nd;
	struct symbol *sym;
	struct map kallsyms_map, vmlinux_map;
	struct machine kallsyms, vmlinux;
	enum map_type type = MAP__FUNCTION;
	u64 mem_start, mem_end;

	/*
	* Step 1:
	*
	* Init the machines that will hold kernel, modules obtained from
	* both vmlinux + .ko files and from /proc/kallsyms split by modules.
	*/
	machine__init(&kallsyms, "", HOST_KERNEL_ID);
	machine__init(&vmlinux, "", HOST_KERNEL_ID);

	/*
	* Step 2:
	*
	* Create the kernel maps for kallsyms and the DSO where we will then
	* load /proc/kallsyms. Also create the modules maps from /proc/modules
	* and find the .ko files that match them in /lib/modules/`uname -r`/.
	*/
	if (machine__create_kernel_maps(&kallsyms) < 0) {
	pr_debug("machine__create_kernel_maps ");
	goto out;
	}

	/*
	* Step 3:
	*
	* Load and split /proc/kallsyms into multiple maps, one per module.
	*/
	if (machine__load_kallsyms(&kallsyms, "/proc/kallsyms", type, NULL) <= 0) {
	pr_debug("dso__load_kallsyms ");
	goto out;
	}

	/*
	* Step 4:
	*
	* kallsyms will be internally on demand sorted by name so that we can
	* find the reference relocation * symbol, i.e. the symbol we will use
	* to see if the running kernel was relocated by checking if it has the
	* same value in the vmlinux file we load.
	*/
	kallsyms_map = machine__kernel_map(&kallsyms, type);

	/*
	* Step 5:
	*
	* Now repeat step 2, this time for the vmlinux file we'll auto-locate.
	*/
	if (machine__create_kernel_maps(&vmlinux) < 0) {
	pr_debug("machine__create_kernel_maps ");
	goto out;
	}

	vmlinux_map = machine__kernel_map(&vmlinux, type);

	/*
	* Step 6:
	*
	* Locate a vmlinux file in the vmlinux path that has a buildid that
	* matches the one of the running kernel.
	*
	* While doing that look if we find the ref reloc symbol, if we find it
	* we'll have its ref_reloc_symbol.unrelocated_addr and then
	* maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines
	* to fixup the symbols.
	*/
	if (machine__load_vmlinux_path(&vmlinux, type,
	vmlinux_matches_kallsyms_filter) <= 0) {
	pr_debug("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n");
	err = TEST_SKIP;
	goto out;
	}

	err = 0;
	/*
	* Step 7:
	*
	* Now look at the symbols in the vmlinux DSO and check if we find all of them
	* in the kallsyms dso. For the ones that are in both, check its names and
	* end addresses too.
	*/
	for (nd = rb_first(&vmlinux_map->dso->symbols[type]); nd; nd = rb_next(nd)) {
	struct symbol pair, first_pair;
	bool backwards = true;

	sym = rb_entry(nd, struct symbol, rb_node);

	if (sym->start == sym->end)
	continue;

	mem_start = vmlinux_map->unmap_ip(vmlinux_map, sym->start);
	mem_end = vmlinux_map->unmap_ip(vmlinux_map, sym->end);

	first_pair = machine__find_kernel_symbol(&kallsyms, type,
	mem_start, NULL, NULL);
	pair = first_pair;

	if (pair && UM(pair->start) == mem_start) {
	next_pair:
	if (strcmp(sym->name, pair->name) == 0) {
	/*
	* kallsyms don't have the symbol end, so we
	* set that by using the next symbol start - 1,
	* in some cases we get this up to a page
	* wrong, trace_kmalloc when I was developing
	* this code was one such example, 2106 bytes
	* off the real size. More than that and we
	* _really_ have a problem.
	*/
	s64 skew = mem_end - UM(pair->end);
	if (llabs(skew) >= page_size)
	pr_debug("%#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n",
	mem_start, sym->name, mem_end,
	UM(pair->end));

	/*
	* Do not count this as a failure, because we
	* could really find a case where it's not
	* possible to get proper function end from
	* kallsyms.
	*/
	continue;

	} else {
	struct rb_node *nnd;
	detour:
	nnd = backwards ? rb_prev(&pair->rb_node) :
	rb_next(&pair->rb_node);
	if (nnd) {
	struct symbol *next = rb_entry(nnd, struct symbol, rb_node);

	if (UM(next->start) == mem_start) {
	pair = next;
	goto next_pair;
	}
	}

	if (backwards) {
	backwards = false;
	pair = first_pair;
	goto detour;
	}

	pr_debug("%#" PRIx64 ": diff name v: %s k: %s\n",
	mem_start, sym->name, pair->name);
	}
	} else
	pr_debug("%#" PRIx64 ": %s not on kallsyms\n",
	mem_start, sym->name);

	err = -1;
	}

	if (!verbose)
	goto out;

	pr_info("Maps only in vmlinux:\n");

	for (nd = rb_first(&vmlinux.kmaps.maps[type]); nd; nd = rb_next(nd)) {
	struct map pos = rb_entry(nd, struct map, rb_node), pair;
	/*
	* If it is the kernel, kallsyms is always "[kernel.kallsyms]", while
	* the kernel will have the path for the vmlinux file being used,
	* so use the short name, less descriptive but the same ("[kernel]" in
	* both cases.
	*/
	pair = map_groups__find_by_name(&kallsyms.kmaps, type,
	(pos->dso->kernel ?
	pos->dso->short_name :
	pos->dso->name));
	if (pair)
	pair->priv = 1;
	else
	map__fprintf(pos, stderr);
	}

	pr_info("Maps in vmlinux with a different name in kallsyms:\n");

	for (nd = rb_first(&vmlinux.kmaps.maps[type]); nd; nd = rb_next(nd)) {
	struct map pos = rb_entry(nd, struct map, rb_node), pair;

	mem_start = vmlinux_map->unmap_ip(vmlinux_map, pos->start);
	mem_end = vmlinux_map->unmap_ip(vmlinux_map, pos->end);

	pair = map_groups__find(&kallsyms.kmaps, type, mem_start);
	if (pair == NULL \|\| pair->priv)
	continue;

	if (pair->start == mem_start) {
	pair->priv = 1;
	pr_info(" %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as",
	pos->start, pos->end, pos->pgoff, pos->dso->name);
	if (mem_end != pair->end)
	pr_info(":\n*%" PRIx64 "-%" PRIx64 " %" PRIx64,
	pair->start, pair->end, pair->pgoff);
	pr_info(" %s\n", pair->dso->name);
	pair->priv = 1;
	}
	}

	pr_info("Maps only in kallsyms:\n");

	for (nd = rb_first(&kallsyms.kmaps.maps[type]);
	nd; nd = rb_next(nd)) {
	struct map *pos = rb_entry(nd, struct map, rb_node);

	if (!pos->priv)
	map__fprintf(pos, stderr);
	}
	out:
	machine__exit(&kallsyms);
	machine__exit(&vmlinux);
	return err;
	}