linux/tools/perf/tests/vmlinux-kallsyms.c
Arnaldo Carvalho de Melo 79b6bb73f8 perf maps: Merge 'struct maps' with 'struct map_groups'
And pick the shortest name: 'struct maps'.

The split existed because we used to have two groups of maps, one for
functions and one for variables, but that only complicated things,
sometimes we needed to figure out what was at some address and then had
to first try it on the functions group and if that failed, fall back to
the variables one.

That split is long gone, so for quite a while we had only one struct
maps per struct map_groups, simplify things by combining those structs.

First patch is the minimum needed to merge both, follow up patches will
rename 'thread->mg' to 'thread->maps', etc.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-hom6639ro7020o708trhxh59@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-11-26 11:07:46 -03:00

253 lines
6.9 KiB
C

// 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;
}