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-rw-r--r--tools/perf/tests/vmlinux-kallsyms.c252
1 files changed, 252 insertions, 0 deletions
diff --git a/tools/perf/tests/vmlinux-kallsyms.c b/tools/perf/tests/vmlinux-kallsyms.c
new file mode 100644
index 000000000..193b7c91b
--- /dev/null
+++ b/tools/perf/tests/vmlinux-kallsyms.c
@@ -0,0 +1,252 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/compiler.h>
+#include <linux/rbtree.h>
+#include <inttypes.h>
+#include <string.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))
+
+int test__vmlinux_matches_kallsyms(struct test *test __maybe_unused, int subtest __maybe_unused)
+{
+ int err = -1;
+ struct rb_node *nd;
+ struct symbol *sym;
+ struct map *kallsyms_map, *vmlinux_map, *map;
+ struct machine kallsyms, vmlinux;
+ struct maps *maps = machine__kernel_maps(&vmlinux);
+ 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);
+
+ /*
+ * 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.
+ * 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("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);
+
+ /*
+ * 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);
+
+ /*
+ * 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_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.
+ */
+ 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 {
+ 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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-16 23:05:17 +0000