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-rw-r--r--tools/perf/tests/vmlinux-kallsyms.c230
1 files changed, 230 insertions, 0 deletions
diff --git a/tools/perf/tests/vmlinux-kallsyms.c b/tools/perf/tests/vmlinux-kallsyms.c
new file mode 100644
index 0000000..0d1cdbe
--- /dev/null
+++ b/tools/perf/tests/vmlinux-kallsyms.c
@@ -0,0 +1,230 @@
+#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;
+}
+
+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;
+ struct ref_reloc_sym ref_reloc_sym = { .name = "_stext", };
+
+ /*
+ * 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 ");
+ return -1;
+ }
+
+ /*
+ * 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);
+
+ sym = map__find_symbol_by_name(kallsyms_map, ref_reloc_sym.name, NULL);
+ if (sym == NULL) {
+ pr_debug("dso__find_symbol_by_name ");
+ goto out;
+ }
+
+ ref_reloc_sym.addr = sym->start;
+
+ /*
+ * 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);
+ map__kmap(vmlinux_map)->ref_reloc_sym = &ref_reloc_sym;
+
+ /*
+ * 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("machine__load_vmlinux_path ");
+ 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;
+
+ first_pair = machine__find_kernel_symbol(&kallsyms, type, sym->start, NULL, NULL);
+ pair = first_pair;
+
+ if (pair && pair->start == sym->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 = sym->end - pair->end;
+ if (llabs(skew) < page_size)
+ continue;
+
+ pr_debug("%#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n",
+ sym->start, sym->name, sym->end, pair->end);
+ } 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 (next->start == sym->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",
+ sym->start, sym->name, pair->name);
+ }
+ } else
+ pr_debug("%#" PRIx64 ": %s not on kallsyms\n", sym->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;
+
+ pair = map_groups__find(&kallsyms.kmaps, type, pos->start);
+ if (pair == NULL || pair->priv)
+ continue;
+
+ if (pair->start == pos->start) {
+ pair->priv = 1;
+ pr_info(" %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as",
+ pos->start, pos->end, pos->pgoff, pos->dso->name);
+ if (pos->pgoff != pair->pgoff || pos->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:
+ return err;
+}
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