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

 // SPDX-License-Identifier: GPL-2.0
 #include <linux/compiler.h>
 #include <linux/rbtree.h>
 #include <inttypes.h>
 #include <string.h>
 #include <ctype.h>
 #include <stdlib.h>
 #include "dso.h"
 #include "map.h"
 #include "symbol.h"
 #include <internal/lib.h> // page_size
 #include "tests.h"
 #include "debug.h"
 #include "machine.h"

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

 static bool is_ignored_symbol(const char *name, char type)
 {
 	/* Symbol names that exactly match to the following are ignored.*/
 	static const char * const ignored_symbols[] = {
 		/*
 		 * Symbols which vary between passes. Passes 1 and 2 must have
 		 * identical symbol lists. The kallsyms_* symbols below are
 		 * only added after pass 1, they would be included in pass 2
 		 * when --all-symbols is specified so exclude them to get a
 		 * stable symbol list.
 		 */
 		"kallsyms_addresses",
 		"kallsyms_offsets",
 		"kallsyms_relative_base",
 		"kallsyms_num_syms",
 		"kallsyms_names",
 		"kallsyms_markers",
 		"kallsyms_token_table",
 		"kallsyms_token_index",
 		/* Exclude linker generated symbols which vary between passes */
 		"_SDA_BASE_",		/* ppc */
 		"_SDA2_BASE_",		/* ppc */
 		NULL
 	};

 	/* Symbol names that begin with the following are ignored.*/
 	static const char * const ignored_prefixes[] = {
 		"$",			/* local symbols for ARM, MIPS, etc. */
 		".L",			/* local labels, .LBB,.Ltmpxxx,.L__unnamed_xx,.LASANPC, etc. */
 		"__crc_",		/* modversions */
 		"__efistub_",		/* arm64 EFI stub namespace */
 		"__kvm_nvhe_$",		/* arm64 local symbols in non-VHE KVM namespace */
 		"__kvm_nvhe_.L",	/* arm64 local symbols in non-VHE KVM namespace */
 		"__AArch64ADRPThunk_",	/* arm64 lld */
 		"__ARMV5PILongThunk_",	/* arm lld */
 		"__ARMV7PILongThunk_",
 		"__ThumbV7PILongThunk_",
 		"__LA25Thunk_",		/* mips lld */
 		"__microLA25Thunk_",
 		NULL
 	};

 	/* Symbol names that end with the following are ignored.*/
 	static const char * const ignored_suffixes[] = {
 		"_from_arm",		/* arm */
 		"_from_thumb",		/* arm */
 		"_veneer",		/* arm */
 		NULL
 	};

 	/* Symbol names that contain the following are ignored.*/
 	static const char * const ignored_matches[] = {
 		".long_branch.",	/* ppc stub */
 		".plt_branch.",		/* ppc stub */
 		NULL
 	};

 	const char * const *p;

 	for (p = ignored_symbols; *p; p++)
 		if (!strcmp(name, *p))
 			return true;

 	for (p = ignored_prefixes; *p; p++)
 		if (!strncmp(name, *p, strlen(*p)))
 			return true;

 	for (p = ignored_suffixes; *p; p++) {
 		int l = strlen(name) - strlen(*p);

 		if (l >= 0 && !strcmp(name + l, *p))
 			return true;
 	}

 	for (p = ignored_matches; *p; p++) {
 		if (strstr(name, *p))
 			return true;
 	}

 	if (type == 'U' || type == 'u')
 		return true;
 	/* exclude debugging symbols */
 	if (type == 'N' || type == 'n')
 		return true;

 	if (toupper(type) == 'A') {
 		/* Keep these useful absolute symbols */
 		if (strcmp(name, "__kernel_syscall_via_break") &&
 		    strcmp(name, "__kernel_syscall_via_epc") &&
 		    strcmp(name, "__kernel_sigtramp") &&
 		    strcmp(name, "__gp"))
 			return true;
 	}

 	return false;
 }

 static int test__vmlinux_matches_kallsyms(struct test_suite *test __maybe_unused,
 					int subtest __maybe_unused)
 {
 	int err = TEST_FAIL;
 	struct rb_node *nd;
 	struct symbol *sym;
 	struct map *kallsyms_map, *vmlinux_map, *map;
 	struct machine kallsyms, vmlinux;
 	struct maps *maps;
 	u64 mem_start, mem_end;
 	bool header_printed;

 	/*
 	 * 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);

 	maps = machine__kernel_maps(&vmlinux);

 	/*
 	 * 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 failed");
 		err = TEST_SKIP;
 		goto out;
 	}

 	/*
 	 * Step 3:
 	 *
 	 * Load and split /proc/kallsyms into multiple maps, one per module.
 	 * Do not use kcore, as this test was designed before kcore support
 	 * and has parts that only make sense if using the non-kcore code.
 	 * XXX: extend it to stress the kcorre code as well, hint: the list
 	 * of modules extracted from /proc/kcore, in its current form, can't
 	 * be compacted against the list of modules found in the "vmlinux"
 	 * code and with the one got from /proc/modules from the "kallsyms" code.
 	 */
 	if (machine__load_kallsyms(&kallsyms, "/proc/kallsyms") <= 0) {
 		pr_debug("machine__load_kallsyms failed");
 		err = TEST_SKIP;
 		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);

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

 	vmlinux_map = machine__kernel_map(&vmlinux);

 	/*
 	 * 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) <= 0) {
 		pr_info("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.
 	 */
 	map__for_each_symbol(vmlinux_map, sym, nd) {
 		struct symbol *pair, *first_pair;

 		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, mem_start, NULL);
 		pair = first_pair;

 		if (pair && UM(pair->start) == mem_start) {
 next_pair:
 			if (arch__compare_symbol_names(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("WARN: %#" 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 {
 				pair = machine__find_kernel_symbol_by_name(&kallsyms, sym->name, NULL);
 				if (pair) {
 					if (UM(pair->start) == mem_start)
 						goto next_pair;

 					pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
 						 mem_start, sym->name, pair->name);
 				} else {
 					pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
 						 mem_start, sym->name, first_pair->name);
 				}

 				continue;
 			}
 		} else if (mem_start == kallsyms.vmlinux_map->end) {
 			/*
 			 * Ignore aliases to _etext, i.e. to the end of the kernel text area,
 			 * such as __indirect_thunk_end.
 			 */
 			continue;
 		} else if (is_ignored_symbol(sym->name, sym->type)) {
 			/*
 			 * Ignore hidden symbols, see scripts/kallsyms.c for the details
 			 */
 			continue;
 		} else {
 			pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n",
 				 mem_start, sym->name);
 		}

 		err = -1;
 	}

 	if (verbose <= 0)
 		goto out;

 	header_printed = false;

 	maps__for_each_entry(maps, map) {
 		struct map *
 		/*
 		 * 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 = maps__find_by_name(kallsyms.kmaps, (map->dso->kernel ?
 								map->dso->short_name :
 								map->dso->name));
 		if (pair) {
 			pair->priv = 1;
 		} else {
 			if (!header_printed) {
 				pr_info("WARN: Maps only in vmlinux:\n");
 				header_printed = true;
 			}
 			map__fprintf(map, stderr);
 		}
 	}

 	header_printed = false;

 	maps__for_each_entry(maps, map) {
 		struct map *pair;

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

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

 		if (pair->start == mem_start) {
 			if (!header_printed) {
 				pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n");
 				header_printed = true;
 			}

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

 	header_printed = false;

 	maps = machine__kernel_maps(&kallsyms);

 	maps__for_each_entry(maps, map) {
 		if (!map->priv) {
 			if (!header_printed) {
 				pr_info("WARN: Maps only in kallsyms:\n");
 				header_printed = true;
 			}
 			map__fprintf(map, stderr);
 		}
 	}
 out:
 	machine__exit(&kallsyms);
 	machine__exit(&vmlinux);
 	return err;
 }

 DEFINE_SUITE("vmlinux symtab matches kallsyms", vmlinux_matches_kallsyms);
	// SPDX-License-Identifier: GPL-2.0
	#include <linux/compiler.h>
	#include <linux/rbtree.h>
	#include <inttypes.h>
	#include <string.h>
	#include <ctype.h>
	#include <stdlib.h>
	#include "dso.h"
	#include "map.h"
	#include "symbol.h"
	#include <internal/lib.h> // page_size
	#include "tests.h"
	#include "debug.h"
	#include "machine.h"

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

	static bool is_ignored_symbol(const char *name, char type)
	{
	/* Symbol names that exactly match to the following are ignored.*/
	static const char * const ignored_symbols[] = {
	/*
	* Symbols which vary between passes. Passes 1 and 2 must have
	* identical symbol lists. The kallsyms_* symbols below are
	* only added after pass 1, they would be included in pass 2
	* when --all-symbols is specified so exclude them to get a
	* stable symbol list.
	*/
	"kallsyms_addresses",
	"kallsyms_offsets",
	"kallsyms_relative_base",
	"kallsyms_num_syms",
	"kallsyms_names",
	"kallsyms_markers",
	"kallsyms_token_table",
	"kallsyms_token_index",
	/* Exclude linker generated symbols which vary between passes */
	"_SDA_BASE_", /* ppc */
	"_SDA2_BASE_", /* ppc */
	NULL
	};

	/* Symbol names that begin with the following are ignored.*/
	static const char * const ignored_prefixes[] = {
	"$", /* local symbols for ARM, MIPS, etc. */
	".L", /* local labels, .LBB,.Ltmpxxx,.L__unnamed_xx,.LASANPC, etc. */
	"__crc_", /* modversions */
	"__efistub_", /* arm64 EFI stub namespace */
	"__kvm_nvhe_$", /* arm64 local symbols in non-VHE KVM namespace */
	"__kvm_nvhe_.L", /* arm64 local symbols in non-VHE KVM namespace */
	"__AArch64ADRPThunk_", /* arm64 lld */
	"__ARMV5PILongThunk_", /* arm lld */
	"__ARMV7PILongThunk_",
	"__ThumbV7PILongThunk_",
	"__LA25Thunk_", /* mips lld */
	"__microLA25Thunk_",
	NULL
	};

	/* Symbol names that end with the following are ignored.*/
	static const char * const ignored_suffixes[] = {
	"_from_arm", /* arm */
	"_from_thumb", /* arm */
	"_veneer", /* arm */
	NULL
	};

	/* Symbol names that contain the following are ignored.*/
	static const char * const ignored_matches[] = {
	".long_branch.", /* ppc stub */
	".plt_branch.", /* ppc stub */
	NULL
	};

	const char * const *p;

	for (p = ignored_symbols; *p; p++)
	if (!strcmp(name, *p))
	return true;

	for (p = ignored_prefixes; *p; p++)
	if (!strncmp(name, p, strlen(p)))
	return true;

	for (p = ignored_suffixes; *p; p++) {
	int l = strlen(name) - strlen(*p);

	if (l >= 0 && !strcmp(name + l, *p))
	return true;
	}

	for (p = ignored_matches; *p; p++) {
	if (strstr(name, *p))
	return true;
	}

	if (type == 'U' \|\| type == 'u')
	return true;
	/* exclude debugging symbols */
	if (type == 'N' \|\| type == 'n')
	return true;

	if (toupper(type) == 'A') {
	/* Keep these useful absolute symbols */
	if (strcmp(name, "__kernel_syscall_via_break") &&
	strcmp(name, "__kernel_syscall_via_epc") &&
	strcmp(name, "__kernel_sigtramp") &&
	strcmp(name, "__gp"))
	return true;
	}

	return false;
	}

	static int test__vmlinux_matches_kallsyms(struct test_suite *test __maybe_unused,
	int subtest __maybe_unused)
	{
	int err = TEST_FAIL;
	struct rb_node *nd;
	struct symbol *sym;
	struct map kallsyms_map, vmlinux_map, *map;
	struct machine kallsyms, vmlinux;
	struct maps *maps;
	u64 mem_start, mem_end;
	bool header_printed;

	/*
	* 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);

	maps = machine__kernel_maps(&vmlinux);

	/*
	* 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 failed");
	err = TEST_SKIP;
	goto out;
	}

	/*
	* Step 3:
	*
	* Load and split /proc/kallsyms into multiple maps, one per module.
	* Do not use kcore, as this test was designed before kcore support
	* and has parts that only make sense if using the non-kcore code.
	* XXX: extend it to stress the kcorre code as well, hint: the list
	* of modules extracted from /proc/kcore, in its current form, can't
	* be compacted against the list of modules found in the "vmlinux"
	* code and with the one got from /proc/modules from the "kallsyms" code.
	*/
	if (machine__load_kallsyms(&kallsyms, "/proc/kallsyms") <= 0) {
	pr_debug("machine__load_kallsyms failed");
	err = TEST_SKIP;
	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);

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

	vmlinux_map = machine__kernel_map(&vmlinux);

	/*
	* 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) <= 0) {
	pr_info("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.
	*/
	map__for_each_symbol(vmlinux_map, sym, nd) {
	struct symbol pair, first_pair;

	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, mem_start, NULL);
	pair = first_pair;

	if (pair && UM(pair->start) == mem_start) {
	next_pair:
	if (arch__compare_symbol_names(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("WARN: %#" 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 {
	pair = machine__find_kernel_symbol_by_name(&kallsyms, sym->name, NULL);
	if (pair) {
	if (UM(pair->start) == mem_start)
	goto next_pair;

	pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
	mem_start, sym->name, pair->name);
	} else {
	pr_debug("WARN: %#" PRIx64 ": diff name v: %s k: %s\n",
	mem_start, sym->name, first_pair->name);
	}

	continue;
	}
	} else if (mem_start == kallsyms.vmlinux_map->end) {
	/*
	* Ignore aliases to _etext, i.e. to the end of the kernel text area,
	* such as __indirect_thunk_end.
	*/
	continue;
	} else if (is_ignored_symbol(sym->name, sym->type)) {
	/*
	* Ignore hidden symbols, see scripts/kallsyms.c for the details
	*/
	continue;
	} else {
	pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n",
	mem_start, sym->name);
	}

	err = -1;
	}

	if (verbose <= 0)
	goto out;

	header_printed = false;

	maps__for_each_entry(maps, map) {
	struct map *
	/*
	* 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 = maps__find_by_name(kallsyms.kmaps, (map->dso->kernel ?
	map->dso->short_name :
	map->dso->name));
	if (pair) {
	pair->priv = 1;
	} else {
	if (!header_printed) {
	pr_info("WARN: Maps only in vmlinux:\n");
	header_printed = true;
	}
	map__fprintf(map, stderr);
	}
	}

	header_printed = false;

	maps__for_each_entry(maps, map) {
	struct map *pair;

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

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

	if (pair->start == mem_start) {
	if (!header_printed) {
	pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n");
	header_printed = true;
	}

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

	header_printed = false;

	maps = machine__kernel_maps(&kallsyms);

	maps__for_each_entry(maps, map) {
	if (!map->priv) {
	if (!header_printed) {
	pr_info("WARN: Maps only in kallsyms:\n");
	header_printed = true;
	}
	map__fprintf(map, stderr);
	}
	}
	out:
	machine__exit(&kallsyms);
	machine__exit(&vmlinux);
	return err;
	}

	DEFINE_SUITE("vmlinux symtab matches kallsyms", vmlinux_matches_kallsyms);