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// 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;
}
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