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Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 

Daniel Borkmann says:

====================
bpf-next 2022-02-17

We've added 29 non-merge commits during the last 8 day(s) which contain
a total of 34 files changed, 1502 insertions(+), 524 deletions(-).

The main changes are:

1) Add BTFGen support to bpftool which allows to use CO-RE in kernels without
   BTF info, from Mauricio Vásquez, Rafael David Tinoco, Lorenzo Fontana and
   Leonardo Di Donato. (Details: https://lpc.events/event/11/contributions/948/)

2) Prepare light skeleton to be used in both kernel module and user space
   and convert bpf_preload.ko to use light skeleton, from Alexei Starovoitov.

3) Rework bpftool's versioning scheme and align with libbpf's version number;
   also add linked libbpf version info to "bpftool version", from Quentin Monnet.

4) Add minimal C++ specific additions to bpftool's skeleton codegen to
   facilitate use of C skeletons in C++ applications, from Andrii Nakryiko.

5) Add BPF verifier sanity check whether relative offset on kfunc calls overflows
   desc->imm and reject the BPF program if the case, from Hou Tao.

6) Fix libbpf to use a dynamically allocated buffer for netlink messages to
   avoid receiving truncated messages on some archs, from Toke Høiland-Jørgensen.

7) Various follow-up fixes to the JIT bpf_prog_pack allocator, from Song Liu.

8) Various BPF selftest and vmtest.sh fixes, from Yucong Sun.

9) Fix bpftool pretty print handling on dumping map keys/values when no BTF
   is available, from Jiri Olsa and Yinjun Zhang.

10) Extend XDP frags selftest to check for invalid length, from Lorenzo Bianconi.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (29 commits)
  bpf: bpf_prog_pack: Set proper size before freeing ro_header
  selftests/bpf: Fix crash in core_reloc when bpftool btfgen fails
  selftests/bpf: Fix vmtest.sh to launch smp vm.
  libbpf: Fix memleak in libbpf_netlink_recv()
  bpftool: Fix C++ additions to skeleton
  bpftool: Fix pretty print dump for maps without BTF loaded
  selftests/bpf: Test "bpftool gen min_core_btf"
  bpftool: Gen min_core_btf explanation and examples
  bpftool: Implement btfgen_get_btf()
  bpftool: Implement "gen min_core_btf" logic
  bpftool: Add gen min_core_btf command
  libbpf: Expose bpf_core_{add,free}_cands() to bpftool
  libbpf: Split bpf_core_apply_relo()
  bpf: Reject kfunc calls that overflow insn->imm
  selftests/bpf: Add Skeleton templated wrapper as an example
  bpftool: Add C++-specific open/load/etc skeleton wrappers
  selftests/bpf: Fix GCC11 compiler warnings in -O2 mode
  bpftool: Fix the error when lookup in no-btf maps
  libbpf: Use dynamically allocated buffer when receiving netlink messages
  libbpf: Fix libbpf.map inheritance chain for LIBBPF_0.7.0
  ...
====================

Link: https://lore.kernel.org/r/20220217232027.29831-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jakub Kicinski 2022-02-17 17:23:51 -08:00
parent 2aed49da6c d24d2a2b0a
commit a3fc4b1d09
34 changed files with 1509 additions and 531 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
kernel/bpf/btf.c
View File

@ -7226,6 +7226,7 @@ int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
{
bool need_cands = relo->kind != BPF_CORE_TYPE_ID_LOCAL;
struct bpf_core_cand_list cands = {};
struct bpf_core_relo_res targ_res;
struct bpf_core_spec *specs;
int err;
@ -7265,13 +7266,19 @@ int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
cands.len = cc->cnt;
/* cand_cache_mutex needs to span the cache lookup and
* copy of btf pointer into bpf_core_cand_list,
* since module can be unloaded while bpf_core_apply_relo_insn
* since module can be unloaded while bpf_core_calc_relo_insn
* is working with module's btf.
*/
}
err = bpf_core_apply_relo_insn((void *)ctx->log, insn, relo->insn_off / 8,
relo, relo_idx, ctx->btf, &cands, specs);
err = bpf_core_calc_relo_insn((void *)ctx->log, relo, relo_idx, ctx->btf, &cands, specs,
&targ_res);
if (err)
goto out;
err = bpf_core_patch_insn((void *)ctx->log, insn, relo->insn_off / 8, relo, relo_idx,
&targ_res);
out:
kfree(specs);
if (need_cands) {

5
kernel/bpf/core.c
View File

@ -827,7 +827,7 @@ int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
struct bpf_prog_pack {
struct list_head list;
void *ptr;
unsigned long bitmap[BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)];
unsigned long bitmap[];
};
#define BPF_PROG_MAX_PACK_PROG_SIZE BPF_PROG_PACK_SIZE
@ -840,7 +840,7 @@ static struct bpf_prog_pack *alloc_new_pack(void)
{
struct bpf_prog_pack *pack;
pack = kzalloc(sizeof(*pack), GFP_KERNEL);
pack = kzalloc(sizeof(*pack) + BITS_TO_BYTES(BPF_PROG_CHUNK_COUNT), GFP_KERNEL);
if (!pack)
return NULL;
pack->ptr = module_alloc(BPF_PROG_PACK_SIZE);
@ -1069,6 +1069,7 @@ bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr,
*rw_header = kvmalloc(size, GFP_KERNEL);
if (!*rw_header) {
bpf_arch_text_copy(&ro_header->size, &size, sizeof(size));
bpf_prog_pack_free(ro_header);
bpf_jit_uncharge_modmem(size);
return NULL;

39
kernel/bpf/inode.c
View File

@ -710,11 +710,10 @@ static DEFINE_MUTEX(bpf_preload_lock);
static int populate_bpffs(struct dentry *parent)
{
struct bpf_preload_info objs[BPF_PRELOAD_LINKS] = {};
struct bpf_link *links[BPF_PRELOAD_LINKS] = {};
int err = 0, i;
/* grab the mutex to make sure the kernel interactions with bpf_preload
* UMD are serialized
* are serialized
*/
mutex_lock(&bpf_preload_lock);
@ -722,40 +721,22 @@ static int populate_bpffs(struct dentry *parent)
if (!bpf_preload_mod_get())
goto out;
if (!bpf_preload_ops->info.tgid) {
/* preload() will start UMD that will load BPF iterator programs */
err = bpf_preload_ops->preload(objs);
if (err)
err = bpf_preload_ops->preload(objs);
if (err)
goto out_put;
for (i = 0; i < BPF_PRELOAD_LINKS; i++) {
bpf_link_inc(objs[i].link);
err = bpf_iter_link_pin_kernel(parent,
objs[i].link_name, objs[i].link);
if (err) {
bpf_link_put(objs[i].link);
goto out_put;
for (i = 0; i < BPF_PRELOAD_LINKS; i++) {
links[i] = bpf_link_by_id(objs[i].link_id);
if (IS_ERR(links[i])) {
err = PTR_ERR(links[i]);
goto out_put;
}
}
for (i = 0; i < BPF_PRELOAD_LINKS; i++) {
err = bpf_iter_link_pin_kernel(parent,
objs[i].link_name, links[i]);
if (err)
goto out_put;
/* do not unlink successfully pinned links even
* if later link fails to pin
*/
links[i] = NULL;
}
/* finish() will tell UMD process to exit */
err = bpf_preload_ops->finish();
if (err)
goto out_put;
}
out_put:
bpf_preload_mod_put();
out:
mutex_unlock(&bpf_preload_lock);
for (i = 0; i < BPF_PRELOAD_LINKS && err; i++)
if (!IS_ERR_OR_NULL(links[i]))
bpf_link_put(links[i]);
return err;
}

7
kernel/bpf/preload/Kconfig
View File

@ -18,10 +18,9 @@ menuconfig BPF_PRELOAD
if BPF_PRELOAD
config BPF_PRELOAD_UMD
tristate "bpf_preload kernel module with user mode driver"
depends on CC_CAN_LINK
depends on m || CC_CAN_LINK_STATIC
tristate "bpf_preload kernel module"
default m
help
This builds bpf_preload kernel module with embedded user mode driver.
This builds bpf_preload kernel module with embedded BPF programs for
introspection in bpffs.
endif

14
kernel/bpf/preload/Makefile
View File

@ -3,16 +3,6 @@
LIBBPF_SRCS = $(srctree)/tools/lib/bpf/
LIBBPF_INCLUDE = $(LIBBPF_SRCS)/..
userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi \
-I $(LIBBPF_INCLUDE) -Wno-unused-result
userprogs := bpf_preload_umd
bpf_preload_umd-objs := iterators/iterators.o
$(obj)/bpf_preload_umd:
$(obj)/bpf_preload_umd_blob.o: $(obj)/bpf_preload_umd
obj-$(CONFIG_BPF_PRELOAD_UMD) += bpf_preload.o
bpf_preload-objs += bpf_preload_kern.o bpf_preload_umd_blob.o
CFLAGS_bpf_preload_kern.o += -I $(LIBBPF_INCLUDE)
bpf_preload-objs += bpf_preload_kern.o

8
kernel/bpf/preload/bpf_preload.h
View File

@ -2,13 +2,13 @@
#ifndef _BPF_PRELOAD_H
#define _BPF_PRELOAD_H
#include <linux/usermode_driver.h>
#include "iterators/bpf_preload_common.h"
struct bpf_preload_info {
char link_name[16];
struct bpf_link *link;
};
struct bpf_preload_ops {
struct umd_info info;
int (*preload)(struct bpf_preload_info *);
int (*finish)(void);
struct module *owner;
};
extern struct bpf_preload_ops *bpf_preload_ops;

133
kernel/bpf/preload/bpf_preload_kern.c
View File

@ -2,101 +2,80 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/module.h>
#include <linux/pid.h>
#include <linux/fs.h>
#include <linux/sched/signal.h>
#include "bpf_preload.h"
#include "iterators/iterators.lskel.h"
extern char bpf_preload_umd_start;
extern char bpf_preload_umd_end;
static struct bpf_link *maps_link, *progs_link;
static struct iterators_bpf *skel;
static int preload(struct bpf_preload_info *obj);
static int finish(void);
static struct bpf_preload_ops umd_ops = {
.info.driver_name = "bpf_preload",
.preload = preload,
.finish = finish,
.owner = THIS_MODULE,
};
static void free_links_and_skel(void)
{
if (!IS_ERR_OR_NULL(maps_link))
bpf_link_put(maps_link);
if (!IS_ERR_OR_NULL(progs_link))
bpf_link_put(progs_link);
iterators_bpf__destroy(skel);
}
static int preload(struct bpf_preload_info *obj)
{
int magic = BPF_PRELOAD_START;
loff_t pos = 0;
int i, err;
ssize_t n;
err = fork_usermode_driver(&umd_ops.info);
if (err)
return err;
/* send the start magic to let UMD proceed with loading BPF progs */
n = kernel_write(umd_ops.info.pipe_to_umh,
&magic, sizeof(magic), &pos);
if (n != sizeof(magic))
return -EPIPE;
/* receive bpf_link IDs and names from UMD */
pos = 0;
for (i = 0; i < BPF_PRELOAD_LINKS; i++) {
n = kernel_read(umd_ops.info.pipe_from_umh,
&obj[i], sizeof(*obj), &pos);
if (n != sizeof(*obj))
return -EPIPE;
}
strlcpy(obj[0].link_name, "maps.debug", sizeof(obj[0].link_name));
obj[0].link = maps_link;
strlcpy(obj[1].link_name, "progs.debug", sizeof(obj[1].link_name));
obj[1].link = progs_link;
return 0;
}
static int finish(void)
{
int magic = BPF_PRELOAD_END;
struct pid *tgid;
loff_t pos = 0;
ssize_t n;
static struct bpf_preload_ops ops = {
.preload = preload,
.owner = THIS_MODULE,
};
/* send the last magic to UMD. It will do a normal exit. */
n = kernel_write(umd_ops.info.pipe_to_umh,
&magic, sizeof(magic), &pos);
if (n != sizeof(magic))
return -EPIPE;
tgid = umd_ops.info.tgid;
if (tgid) {
wait_event(tgid->wait_pidfd, thread_group_exited(tgid));
umd_cleanup_helper(&umd_ops.info);
}
return 0;
}
static int __init load_umd(void)
static int load_skel(void)
{
int err;
err = umd_load_blob(&umd_ops.info, &bpf_preload_umd_start,
&bpf_preload_umd_end - &bpf_preload_umd_start);
skel = iterators_bpf__open();
if (!skel)
return -ENOMEM;
err = iterators_bpf__load(skel);
if (err)
return err;
bpf_preload_ops = &umd_ops;
goto out;
err = iterators_bpf__attach(skel);
if (err)
goto out;
maps_link = bpf_link_get_from_fd(skel->links.dump_bpf_map_fd);
if (IS_ERR(maps_link)) {
err = PTR_ERR(maps_link);
goto out;
}
progs_link = bpf_link_get_from_fd(skel->links.dump_bpf_prog_fd);
if (IS_ERR(progs_link)) {
err = PTR_ERR(progs_link);
goto out;
}
return 0;
out:
free_links_and_skel();
return err;
}
static void __exit fini_umd(void)
static int __init load(void)
{
struct pid *tgid;
int err;
bpf_preload_ops = NULL;
/* kill UMD in case it's still there due to earlier error */
tgid = umd_ops.info.tgid;
if (tgid) {
kill_pid(tgid, SIGKILL, 1);
wait_event(tgid->wait_pidfd, thread_group_exited(tgid));
umd_cleanup_helper(&umd_ops.info);
}
umd_unload_blob(&umd_ops.info);
err = load_skel();
if (err)
return err;
bpf_preload_ops = &ops;
return err;
}
late_initcall(load_umd);
module_exit(fini_umd);
static void __exit fini(void)
{
bpf_preload_ops = NULL;
free_links_and_skel();
}
late_initcall(load);
module_exit(fini);
MODULE_LICENSE("GPL");

7
kernel/bpf/preload/bpf_preload_umd_blob.S
View File

@ -1,7 +0,0 @@
/* SPDX-License-Identifier: GPL-2.0 */
.section .init.rodata, "a"
.global bpf_preload_umd_start
bpf_preload_umd_start:
.incbin "kernel/bpf/preload/bpf_preload_umd"
.global bpf_preload_umd_end
bpf_preload_umd_end:

13
kernel/bpf/preload/iterators/bpf_preload_common.h
View File

@ -1,13 +0,0 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _BPF_PRELOAD_COMMON_H
#define _BPF_PRELOAD_COMMON_H
#define BPF_PRELOAD_START 0x5555
#define BPF_PRELOAD_END 0xAAAA
struct bpf_preload_info {
char link_name[16];
int link_id;
};
#endif

108
kernel/bpf/preload/iterators/iterators.c
View File

@ -1,108 +0,0 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <bpf/libbpf.h>
#include <bpf/bpf.h>
#include <sys/mount.h>
#include "iterators.lskel.h"
#include "bpf_preload_common.h"
int to_kernel = -1;
int from_kernel = 0;
static int __bpf_obj_get_info_by_fd(int bpf_fd, void *info, __u32 *info_len)
{
union bpf_attr attr;
int err;
memset(&attr, 0, sizeof(attr));
attr.info.bpf_fd = bpf_fd;
attr.info.info_len = *info_len;
attr.info.info = (long) info;
err = skel_sys_bpf(BPF_OBJ_GET_INFO_BY_FD, &attr, sizeof(attr));
if (!err)
*info_len = attr.info.info_len;
return err;
}
static int send_link_to_kernel(int link_fd, const char *link_name)
{
struct bpf_preload_info obj = {};
struct bpf_link_info info = {};
__u32 info_len = sizeof(info);
int err;
err = __bpf_obj_get_info_by_fd(link_fd, &info, &info_len);
if (err)
return err;
obj.link_id = info.id;
if (strlen(link_name) >= sizeof(obj.link_name))
return -E2BIG;
strcpy(obj.link_name, link_name);
if (write(to_kernel, &obj, sizeof(obj)) != sizeof(obj))
return -EPIPE;
return 0;
}
int main(int argc, char **argv)
{
struct iterators_bpf *skel;
int err, magic;
int debug_fd;
debug_fd = open("/dev/console", O_WRONLY | O_NOCTTY | O_CLOEXEC);
if (debug_fd < 0)
return 1;
to_kernel = dup(1);
close(1);
dup(debug_fd);
/* now stdin and stderr point to /dev/console */
read(from_kernel, &magic, sizeof(magic));
if (magic != BPF_PRELOAD_START) {
printf("bad start magic %d\n", magic);
return 1;
}
/* libbpf opens BPF object and loads it into the kernel */
skel = iterators_bpf__open_and_load();
if (!skel) {
/* iterators.skel.h is little endian.
* libbpf doesn't support automatic little->big conversion
* of BPF bytecode yet.
* The program load will fail in such case.
*/
printf("Failed load could be due to wrong endianness\n");
return 1;
}
err = iterators_bpf__attach(skel);
if (err)
goto cleanup;
/* send two bpf_link IDs with names to the kernel */
err = send_link_to_kernel(skel->links.dump_bpf_map_fd, "maps.debug");
if (err)
goto cleanup;
err = send_link_to_kernel(skel->links.dump_bpf_prog_fd, "progs.debug");
if (err)
goto cleanup;
/* The kernel will proceed with pinnging the links in bpffs.
* UMD will wait on read from pipe.
*/
read(from_kernel, &magic, sizeof(magic));
if (magic != BPF_PRELOAD_END) {
printf("bad final magic %d\n", magic);
err = -EINVAL;
}
cleanup:
iterators_bpf__destroy(skel);
return err != 0;
}

141
kernel/bpf/preload/iterators/iterators.lskel.h
View File

@ -3,8 +3,6 @@
#ifndef __ITERATORS_BPF_SKEL_H__
#define __ITERATORS_BPF_SKEL_H__
#include <stdlib.h>
#include <bpf/bpf.h>
#include <bpf/skel_internal.h>
struct iterators_bpf {
@ -70,31 +68,28 @@ iterators_bpf__destroy(struct iterators_bpf *skel)
iterators_bpf__detach(skel);
skel_closenz(skel->progs.dump_bpf_map.prog_fd);
skel_closenz(skel->progs.dump_bpf_prog.prog_fd);
munmap(skel->rodata, 4096);
skel_free_map_data(skel->rodata, skel->maps.rodata.initial_value, 4096);
skel_closenz(skel->maps.rodata.map_fd);
free(skel);
skel_free(skel);
}
static inline struct iterators_bpf *
iterators_bpf__open(void)
{
struct iterators_bpf *skel;
skel = calloc(sizeof(*skel), 1);
skel = skel_alloc(sizeof(*skel));
if (!skel)
goto cleanup;
skel->ctx.sz = (void *)&skel->links - (void *)skel;
skel->rodata =
mmap(NULL, 4096, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_ANONYMOUS, -1, 0);
if (skel->rodata == (void *) -1)
goto cleanup;
memcpy(skel->rodata, (void *)"\
skel->rodata = skel_prep_map_data((void *)"\
\x20\x20\x69\x64\x20\x6e\x61\x6d\x65\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\
\x20\x20\x20\x6d\x61\x78\x5f\x65\x6e\x74\x72\x69\x65\x73\x0a\0\x25\x34\x75\x20\
\x25\x2d\x31\x36\x73\x25\x36\x64\x0a\0\x20\x20\x69\x64\x20\x6e\x61\x6d\x65\x20\
\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x20\x61\x74\x74\x61\x63\x68\x65\
\x64\x0a\0\x25\x34\x75\x20\x25\x2d\x31\x36\x73\x20\x25\x73\x20\x25\x73\x0a\0", 98);
skel->maps.rodata.initial_value = (__u64)(long)skel->rodata;
\x64\x0a\0\x25\x34\x75\x20\x25\x2d\x31\x36\x73\x20\x25\x73\x20\x25\x73\x0a\0", 4096, 98);
if (!skel->rodata)
goto cleanup;
skel->maps.rodata.initial_value = (__u64) (long) skel->rodata;
return skel;
cleanup:
iterators_bpf__destroy(skel);
@ -326,7 +321,7 @@ iterators_bpf__load(struct iterators_bpf *skel)
\0\0\x01\0\0\0\0\0\0\0\x13\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x10\0\0\0\0\0\
\0\0\x62\x70\x66\x5f\x69\x74\x65\x72\x5f\x62\x70\x66\x5f\x70\x72\x6f\x67\0\0\0\
\0\0\0\0";
opts.insns_sz = 2184;
opts.insns_sz = 2216;
opts.insns = (void *)"\
\xbf\x16\0\0\0\0\0\0\xbf\xa1\0\0\0\0\0\0\x07\x01\0\0\x78\xff\xff\xff\xb7\x02\0\
\0\x88\0\0\0\xb7\x03\0\0\0\0\0\0\x85\0\0\0\x71\0\0\0\x05\0\x14\0\0\0\0\0\x61\
@ -343,70 +338,72 @@ iterators_bpf__load(struct iterators_bpf *skel)
\0\0\x18\x62\0\0\0\0\0\0\0\0\0\0\x30\x0e\0\0\xb7\x03\0\0\x1c\0\0\0\x85\0\0\0\
\xa6\0\0\0\xbf\x07\0\0\0\0\0\0\xc5\x07\xd4\xff\0\0\0\0\x63\x7a\x78\xff\0\0\0\0\
\x61\xa0\x78\xff\0\0\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\x80\x0e\0\0\x63\x01\0\0\0\
\0\0\0\x61\x60\x20\0\0\0\0\0\x15\0\x03\0\0\0\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\
\0\0\0\x61\x60\x1c\0\0\0\0\0\x15\0\x03\0\0\0\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\
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\0\0\0\0\0\0\0\0\0\0\0\0\0\x61\x10\0\0\0\0\0\0\x63\x06\x18\0\0\0\0\0\xb7\0\0\0\
\0\0\0\0\x95\0\0\0\0\0\0\0";
err = bpf_load_and_run(&opts);
if (err < 0)
return err;
skel->rodata =
mmap(skel->rodata, 4096, PROT_READ, MAP_SHARED | MAP_FIXED,
skel->maps.rodata.map_fd, 0);
skel->rodata = skel_finalize_map_data(&skel->maps.rodata.initial_value,
4096, PROT_READ, skel->maps.rodata.map_fd);
if (!skel->rodata)
return -ENOMEM;
return 0;
}

40
kernel/bpf/syscall.c
View File

@ -985,6 +985,7 @@ struct bpf_map *bpf_map_get(u32 ufd)
return map;
}
EXPORT_SYMBOL(bpf_map_get);
struct bpf_map *bpf_map_get_with_uref(u32 ufd)
{
@ -2492,6 +2493,7 @@ void bpf_link_put(struct bpf_link *link)
bpf_link_free(link);
}
}
EXPORT_SYMBOL(bpf_link_put);
static int bpf_link_release(struct inode *inode, struct file *filp)
{
@ -2634,6 +2636,7 @@ struct bpf_link *bpf_link_get_from_fd(u32 ufd)
return link;
}
EXPORT_SYMBOL(bpf_link_get_from_fd);
struct bpf_tracing_link {
struct bpf_link link;
@ -4759,23 +4762,52 @@ static bool syscall_prog_is_valid_access(int off, int size,
return true;
}
BPF_CALL_3(bpf_sys_bpf, int, cmd, void *, attr, u32, attr_size)
BPF_CALL_3(bpf_sys_bpf, int, cmd, union bpf_attr *, attr, u32, attr_size)
{
struct bpf_prog * __maybe_unused prog;
switch (cmd) {
case BPF_MAP_CREATE:
case BPF_MAP_UPDATE_ELEM:
case BPF_MAP_FREEZE:
case BPF_PROG_LOAD:
case BPF_BTF_LOAD:
case BPF_LINK_CREATE:
case BPF_RAW_TRACEPOINT_OPEN:
break;
/* case BPF_PROG_TEST_RUN:
* is not part of this list to prevent recursive test_run
*/
#ifdef CONFIG_BPF_JIT /* __bpf_prog_enter_sleepable used by trampoline and JIT */
case BPF_PROG_TEST_RUN:
if (attr->test.data_in || attr->test.data_out ||
attr->test.ctx_out || attr->test.duration ||
attr->test.repeat || attr->test.flags)
return -EINVAL;
prog = bpf_prog_get_type(attr->test.prog_fd, BPF_PROG_TYPE_SYSCALL);
if (IS_ERR(prog))
return PTR_ERR(prog);
if (attr->test.ctx_size_in < prog->aux->max_ctx_offset ||
attr->test.ctx_size_in > U16_MAX) {
bpf_prog_put(prog);
return -EINVAL;
}
if (!__bpf_prog_enter_sleepable(prog)) {
/* recursion detected */
bpf_prog_put(prog);
return -EBUSY;
}
attr->test.retval = bpf_prog_run(prog, (void *) (long) attr->test.ctx_in);
__bpf_prog_exit_sleepable(prog, 0 /* bpf_prog_run does runtime stats */);
bpf_prog_put(prog);
return 0;
#endif
default:
return -EINVAL;
}
return __sys_bpf(cmd, KERNEL_BPFPTR(attr), attr_size);
}
EXPORT_SYMBOL(bpf_sys_bpf);
static const struct bpf_func_proto bpf_sys_bpf_proto = {
.func = bpf_sys_bpf,

11
kernel/bpf/verifier.c
View File

@ -1842,6 +1842,7 @@ static int add_kfunc_call(struct bpf_verifier_env *env, u32 func_id, s16 offset)
struct bpf_kfunc_desc *desc;
const char *func_name;
struct btf *desc_btf;
unsigned long call_imm;
unsigned long addr;
int err;
@ -1926,9 +1927,17 @@ static int add_kfunc_call(struct bpf_verifier_env *env, u32 func_id, s16 offset)
return -EINVAL;
}
call_imm = BPF_CALL_IMM(addr);
/* Check whether or not the relative offset overflows desc->imm */
if ((unsigned long)(s32)call_imm != call_imm) {
verbose(env, "address of kernel function %s is out of range\n",
func_name);
return -EINVAL;
}
desc = &tab->descs[tab->nr_descs++];
desc->func_id = func_id;
desc->imm = BPF_CALL_IMM(addr);
desc->imm = call_imm;
desc->offset = offset;
err = btf_distill_func_proto(&env->log, desc_btf,
func_proto, func_name,

90
tools/bpf/bpftool/Documentation/bpftool-gen.rst
View File

@ -25,6 +25,7 @@ GEN COMMANDS
| **bpftool** **gen object** *OUTPUT_FILE* *INPUT_FILE* [*INPUT_FILE*...]
| **bpftool** **gen skeleton** *FILE* [**name** *OBJECT_NAME*]
| **bpftool** **gen min_core_btf** *INPUT* *OUTPUT* *OBJECT* [*OBJECT*...]
| **bpftool** **gen help**
DESCRIPTION
@ -149,6 +150,26 @@ DESCRIPTION
(non-read-only) data from userspace, with same simplicity
as for BPF side.
**bpftool** **gen min_core_btf** *INPUT* *OUTPUT* *OBJECT* [*OBJECT*...]
Generate a minimum BTF file as *OUTPUT*, derived from a given
*INPUT* BTF file, containing all needed BTF types so one, or
more, given eBPF objects CO-RE relocations may be satisfied.
When kernels aren't compiled with CONFIG_DEBUG_INFO_BTF,
libbpf, when loading an eBPF object, has to rely on external
BTF files to be able to calculate CO-RE relocations.
Usually, an external BTF file is built from existing kernel
DWARF data using pahole. It contains all the types used by
its respective kernel image and, because of that, is big.
The min_core_btf feature builds smaller BTF files, customized
to one or multiple eBPF objects, so they can be distributed
together with an eBPF CO-RE based application, turning the
application portable to different kernel versions.
Check examples bellow for more information how to use it.
**bpftool gen help**
Print short help message.
@ -215,7 +236,9 @@ This is example BPF application with two BPF programs and a mix of BPF maps
and global variables. Source code is split across two source code files.
**$ clang -target bpf -g example1.bpf.c -o example1.bpf.o**
**$ clang -target bpf -g example2.bpf.c -o example2.bpf.o**
**$ bpftool gen object example.bpf.o example1.bpf.o example2.bpf.o**
This set of commands compiles *example1.bpf.c* and *example2.bpf.c*
@ -329,3 +352,70 @@ BPF ELF object file *example.bpf.o*.
my_static_var: 7
This is a stripped-out version of skeleton generated for above example code.
min_core_btf
------------
**$ bpftool btf dump file 5.4.0-example.btf format raw**
::
[1] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
[2] CONST '(anon)' type_id=1
[3] VOLATILE '(anon)' type_id=1
[4] ARRAY '(anon)' type_id=1 index_type_id=21 nr_elems=2
[5] PTR '(anon)' type_id=8
[6] CONST '(anon)' type_id=5
[7] INT 'char' size=1 bits_offset=0 nr_bits=8 encoding=(none)
[8] CONST '(anon)' type_id=7
[9] INT 'unsigned int' size=4 bits_offset=0 nr_bits=32 encoding=(none)
<long output>
**$ bpftool btf dump file one.bpf.o format raw**
::
[1] PTR '(anon)' type_id=2
[2] STRUCT 'trace_event_raw_sys_enter' size=64 vlen=4
'ent' type_id=3 bits_offset=0
'id' type_id=7 bits_offset=64
'args' type_id=9 bits_offset=128
'__data' type_id=12 bits_offset=512
[3] STRUCT 'trace_entry' size=8 vlen=4
'type' type_id=4 bits_offset=0
'flags' type_id=5 bits_offset=16
'preempt_count' type_id=5 bits_offset=24
<long output>
**$ bpftool gen min_core_btf 5.4.0-example.btf 5.4.0-smaller.btf one.bpf.o**
**$ bpftool btf dump file 5.4.0-smaller.btf format raw**
::
[1] TYPEDEF 'pid_t' type_id=6
[2] STRUCT 'trace_event_raw_sys_enter' size=64 vlen=1
'args' type_id=4 bits_offset=128
[3] STRUCT 'task_struct' size=9216 vlen=2
'pid' type_id=1 bits_offset=17920
'real_parent' type_id=7 bits_offset=18048
[4] ARRAY '(anon)' type_id=5 index_type_id=8 nr_elems=6
[5] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
[6] TYPEDEF '__kernel_pid_t' type_id=8
[7] PTR '(anon)' type_id=3
[8] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED
<end>
Now, the "5.4.0-smaller.btf" file may be used by libbpf as an external BTF file
when loading the "one.bpf.o" object into the "5.4.0-example" kernel. Note that
the generated BTF file won't allow other eBPF objects to be loaded, just the
ones given to min_core_btf.
::
LIBBPF_OPTS(bpf_object_open_opts, opts, .btf_custom_path = "5.4.0-smaller.btf");
struct bpf_object *obj;
obj = bpf_object__open_file("one.bpf.o", &opts);
...

13
tools/bpf/bpftool/Documentation/common_options.rst
View File

@ -4,12 +4,13 @@
Print short help message (similar to **bpftool help**).
-V, --version
Print version number (similar to **bpftool version**), and optional
features that were included when bpftool was compiled. Optional
features include linking against libbfd to provide the disassembler
for JIT-ted programs (**bpftool prog dump jited**) and usage of BPF
skeletons (some features like **bpftool prog profile** or showing
pids associated to BPF objects may rely on it).
Print bpftool's version number (similar to **bpftool version**), the
number of the libbpf version in use, and optional features that were
included when bpftool was compiled. Optional features include linking
against libbfd to provide the disassembler for JIT-ted programs
(**bpftool prog dump jited**) and usage of BPF skeletons (some
features like **bpftool prog profile** or showing pids associated to
BPF objects may rely on it).
-j, --json
Generate JSON output. For commands that cannot produce JSON, this

14
tools/bpf/bpftool/Makefile
View File

@ -34,14 +34,10 @@ LIBBPF_BOOTSTRAP_INCLUDE := $(LIBBPF_BOOTSTRAP_DESTDIR)/include
LIBBPF_BOOTSTRAP_HDRS_DIR := $(LIBBPF_BOOTSTRAP_INCLUDE)/bpf
LIBBPF_BOOTSTRAP := $(LIBBPF_BOOTSTRAP_OUTPUT)libbpf.a
# We need to copy hashmap.h and nlattr.h which is not otherwise exported by
# libbpf, but still required by bpftool.
LIBBPF_INTERNAL_HDRS := $(addprefix $(LIBBPF_HDRS_DIR)/,hashmap.h nlattr.h)
LIBBPF_BOOTSTRAP_INTERNAL_HDRS := $(addprefix $(LIBBPF_BOOTSTRAP_HDRS_DIR)/,hashmap.h)
ifeq ($(BPFTOOL_VERSION),)
BPFTOOL_VERSION := $(shell make -rR --no-print-directory -sC ../../.. kernelversion)
endif
# We need to copy hashmap.h, nlattr.h, relo_core.h and libbpf_internal.h
# which are not otherwise exported by libbpf, but still required by bpftool.
LIBBPF_INTERNAL_HDRS := $(addprefix $(LIBBPF_HDRS_DIR)/,hashmap.h nlattr.h relo_core.h libbpf_internal.h)
LIBBPF_BOOTSTRAP_INTERNAL_HDRS := $(addprefix $(LIBBPF_BOOTSTRAP_HDRS_DIR)/,hashmap.h relo_core.h libbpf_internal.h)
$(LIBBPF_OUTPUT) $(BOOTSTRAP_OUTPUT) $(LIBBPF_BOOTSTRAP_OUTPUT) $(LIBBPF_HDRS_DIR) $(LIBBPF_BOOTSTRAP_HDRS_DIR):
$(QUIET_MKDIR)mkdir -p $@
@ -83,7 +79,9 @@ CFLAGS += -DPACKAGE='"bpftool"' -D__EXPORTED_HEADERS__ \
-I$(srctree)/kernel/bpf/ \
-I$(srctree)/tools/include \
-I$(srctree)/tools/include/uapi
ifneq ($(BPFTOOL_VERSION),)
CFLAGS += -DBPFTOOL_VERSION='"$(BPFTOOL_VERSION)"'
endif
ifneq ($(EXTRA_CFLAGS),)
CFLAGS += $(EXTRA_CFLAGS)
endif

6
tools/bpf/bpftool/bash-completion/bpftool
View File

@ -1003,9 +1003,13 @@ _bpftool()
;;
esac
;;
min_core_btf)
_filedir
return 0
;;
*)
[[ $prev == $object ]] && \
COMPREPLY=( $( compgen -W 'object skeleton help' -- "$cur" ) )
COMPREPLY=( $( compgen -W 'object skeleton help min_core_btf' -- "$cur" ) )
;;
esac
;;

654
tools/bpf/bpftool/gen.c
View File

@ -14,6 +14,7 @@
#include <unistd.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include <bpf/libbpf_internal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
@ -472,7 +473,7 @@ static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
continue;
if (bpf_map__is_internal(map) &&
(bpf_map__map_flags(map) & BPF_F_MMAPABLE))
printf("\tmunmap(skel->%1$s, %2$zd);\n",
printf("\tskel_free_map_data(skel->%1$s, skel->maps.%1$s.initial_value, %2$zd);\n",
ident, bpf_map_mmap_sz(map));
codegen("\
\n\
@ -481,7 +482,7 @@ static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
}
codegen("\
\n\
free(skel); \n\
skel_free(skel); \n\
} \n\
",
obj_name);
@ -525,7 +526,7 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
{ \n\
struct %1$s *skel; \n\
\n\
skel = calloc(sizeof(*skel), 1); \n\
skel = skel_alloc(sizeof(*skel)); \n\
if (!skel) \n\
goto cleanup; \n\
skel->ctx.sz = (void *)&skel->links - (void *)skel; \n\
@ -543,19 +544,18 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
continue;
codegen("\
\n\
skel->%1$s = \n\
mmap(NULL, %2$zd, PROT_READ | PROT_WRITE,\n\
MAP_SHARED | MAP_ANONYMOUS, -1, 0); \n\
if (skel->%1$s == (void *) -1) \n\
goto cleanup; \n\
memcpy(skel->%1$s, (void *)\"\\ \n\
", ident, bpf_map_mmap_sz(map));
\n\
skel->%1$s = skel_prep_map_data((void *)\"\\ \n\
", ident);
mmap_data = bpf_map__initial_value(map, &mmap_size);
print_hex(mmap_data, mmap_size);
printf("\", %2$zd);\n"
"\tskel->maps.%1$s.initial_value = (__u64)(long)skel->%1$s;\n",
ident, mmap_size);
codegen("\
\n\
\", %1$zd, %2$zd); \n\
if (!skel->%3$s) \n\
goto cleanup; \n\
skel->maps.%3$s.initial_value = (__u64) (long) skel->%3$s;\n\
", bpf_map_mmap_sz(map), mmap_size, ident);
}
codegen("\
\n\
@ -611,9 +611,13 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
else
mmap_flags = "PROT_READ | PROT_WRITE";
printf("\tskel->%1$s =\n"
"\t\tmmap(skel->%1$s, %2$zd, %3$s, MAP_SHARED | MAP_FIXED,\n"
"\t\t\tskel->maps.%1$s.map_fd, 0);\n",
codegen("\
\n\
skel->%1$s = skel_finalize_map_data(&skel->maps.%1$s.initial_value, \n\
%2$zd, %3$s, skel->maps.%1$s.map_fd);\n\
if (!skel->%1$s) \n\
return -ENOMEM; \n\
",
ident, bpf_map_mmap_sz(map), mmap_flags);
}
codegen("\
@ -751,8 +755,6 @@ static int do_skeleton(int argc, char **argv)
#ifndef %2$s \n\
#define %2$s \n\
\n\
#include <stdlib.h> \n\
#include <bpf/bpf.h> \n\
#include <bpf/skel_internal.h> \n\
\n\
struct %1$s { \n\
@ -830,6 +832,16 @@ static int do_skeleton(int argc, char **argv)
codegen("\
\n\
\n\
#ifdef __cplusplus \n\
static inline struct %1$s *open(const struct bpf_object_open_opts *opts = nullptr);\n\
static inline struct %1$s *open_and_load(); \n\
static inline int load(struct %1$s *skel); \n\
static inline int attach(struct %1$s *skel); \n\
static inline void detach(struct %1$s *skel); \n\
static inline void destroy(struct %1$s *skel); \n\
static inline const void *elf_bytes(size_t *sz); \n\
#endif /* __cplusplus */ \n\
}; \n\
\n\
static void \n\
@ -1024,9 +1036,19 @@ static int do_skeleton(int argc, char **argv)
\"; \n\
} \n\
\n\
#endif /* %s */ \n\
#ifdef __cplusplus \n\
struct %1$s *%1$s::open(const struct bpf_object_open_opts *opts) { return %1$s__open_opts(opts); }\n\
struct %1$s *%1$s::open_and_load() { return %1$s__open_and_load(); } \n\
int %1$s::load(struct %1$s *skel) { return %1$s__load(skel); } \n\
int %1$s::attach(struct %1$s *skel) { return %1$s__attach(skel); } \n\
void %1$s::detach(struct %1$s *skel) { %1$s__detach(skel); } \n\
void %1$s::destroy(struct %1$s *skel) { %1$s__destroy(skel); } \n\
const void *%1$s::elf_bytes(size_t *sz) { return %1$s__elf_bytes(sz); } \n\
#endif /* __cplusplus */ \n\
\n\
#endif /* %2$s */ \n\
",
header_guard);
obj_name, header_guard);
err = 0;
out:
bpf_object__close(obj);
@ -1087,6 +1109,7 @@ static int do_help(int argc, char **argv)
fprintf(stderr,
"Usage: %1$s %2$s object OUTPUT_FILE INPUT_FILE [INPUT_FILE...]\n"
" %1$s %2$s skeleton FILE [name OBJECT_NAME]\n"
" %1$s %2$s min_core_btf INPUT OUTPUT OBJECT [OBJECT...]\n"
" %1$s %2$s help\n"
"\n"
" " HELP_SPEC_OPTIONS " |\n"
@ -1097,10 +1120,593 @@ static int do_help(int argc, char **argv)
return 0;
}
static int btf_save_raw(const struct btf *btf, const char *path)
{
const void *data;
FILE *f = NULL;
__u32 data_sz;
int err = 0;
data = btf__raw_data(btf, &data_sz);
if (!data)
return -ENOMEM;
f = fopen(path, "wb");
if (!f)
return -errno;
if (fwrite(data, 1, data_sz, f) != data_sz)
err = -errno;
fclose(f);
return err;
}
struct btfgen_info {
struct btf *src_btf;
struct btf *marked_btf; /* btf structure used to mark used types */
};
static size_t btfgen_hash_fn(const void *key, void *ctx)
{
return (size_t)key;
}
static bool btfgen_equal_fn(const void *k1, const void *k2, void *ctx)
{
return k1 == k2;
}
static void *u32_as_hash_key(__u32 x)
{
return (void *)(uintptr_t)x;
}
static void btfgen_free_info(struct btfgen_info *info)
{
if (!info)
return;
btf__free(info->src_btf);
btf__free(info->marked_btf);
free(info);
}
static struct btfgen_info *
btfgen_new_info(const char *targ_btf_path)
{
struct btfgen_info *info;
int err;
info = calloc(1, sizeof(*info));
if (!info)
return NULL;
info->src_btf = btf__parse(targ_btf_path, NULL);
if (!info->src_btf) {
err = -errno;
p_err("failed parsing '%s' BTF file: %s", targ_btf_path, strerror(errno));
goto err_out;
}
info->marked_btf = btf__parse(targ_btf_path, NULL);
if (!info->marked_btf) {
err = -errno;
p_err("failed parsing '%s' BTF file: %s", targ_btf_path, strerror(errno));
goto err_out;
}
return info;
err_out:
btfgen_free_info(info);
errno = -err;
return NULL;
}
#define MARKED UINT32_MAX
static void btfgen_mark_member(struct btfgen_info *info, int type_id, int idx)
{
const struct btf_type *t = btf__type_by_id(info->marked_btf, type_id);
struct btf_member *m = btf_members(t) + idx;
m->name_off = MARKED;
}
static int
btfgen_mark_type(struct btfgen_info *info, unsigned int type_id, bool follow_pointers)
{
const struct btf_type *btf_type = btf__type_by_id(info->src_btf, type_id);
struct btf_type *cloned_type;
struct btf_param *param;
struct btf_array *array;
int err, i;
if (type_id == 0)
return 0;
/* mark type on cloned BTF as used */
cloned_type = (struct btf_type *) btf__type_by_id(info->marked_btf, type_id);
cloned_type->name_off = MARKED;
/* recursively mark other types needed by it */
switch (btf_kind(btf_type)) {
case BTF_KIND_UNKN:
case BTF_KIND_INT:
case BTF_KIND_FLOAT:
case BTF_KIND_ENUM:
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
break;
case BTF_KIND_PTR:
if (follow_pointers) {
err = btfgen_mark_type(info, btf_type->type, follow_pointers);
if (err)
return err;
}
break;
case BTF_KIND_CONST:
case BTF_KIND_VOLATILE:
case BTF_KIND_TYPEDEF:
err = btfgen_mark_type(info, btf_type->type, follow_pointers);
if (err)
return err;
break;
case BTF_KIND_ARRAY:
array = btf_array(btf_type);
/* mark array type */
err = btfgen_mark_type(info, array->type, follow_pointers);
/* mark array's index type */
err = err ? : btfgen_mark_type(info, array->index_type, follow_pointers);
if (err)
return err;
break;
case BTF_KIND_FUNC_PROTO:
/* mark ret type */
err = btfgen_mark_type(info, btf_type->type, follow_pointers);
if (err)
return err;
/* mark parameters types */
param = btf_params(btf_type);
for (i = 0; i < btf_vlen(btf_type); i++) {
err = btfgen_mark_type(info, param->type, follow_pointers);
if (err)
return err;
param++;
}
break;
/* tells if some other type needs to be handled */
default:
p_err("unsupported kind: %s (%d)", btf_kind_str(btf_type), type_id);
return -EINVAL;
}
return 0;
}
static int btfgen_record_field_relo(struct btfgen_info *info, struct bpf_core_spec *targ_spec)
{
struct btf *btf = info->src_btf;
const struct btf_type *btf_type;
struct btf_member *btf_member;
struct btf_array *array;
unsigned int type_id = targ_spec->root_type_id;
int idx, err;
/* mark root type */
btf_type = btf__type_by_id(btf, type_id);
err = btfgen_mark_type(info, type_id, false);
if (err)
return err;
/* mark types for complex types (arrays, unions, structures) */
for (int i = 1; i < targ_spec->raw_len; i++) {
/* skip typedefs and mods */
while (btf_is_mod(btf_type) || btf_is_typedef(btf_type)) {
type_id = btf_type->type;
btf_type = btf__type_by_id(btf, type_id);
}
switch (btf_kind(btf_type)) {
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
idx = targ_spec->raw_spec[i];
btf_member = btf_members(btf_type) + idx;
/* mark member */
btfgen_mark_member(info, type_id, idx);
/* mark member's type */
type_id = btf_member->type;
btf_type = btf__type_by_id(btf, type_id);
err = btfgen_mark_type(info, type_id, false);
if (err)
return err;
break;
case BTF_KIND_ARRAY:
array = btf_array(btf_type);
type_id = array->type;
btf_type = btf__type_by_id(btf, type_id);
break;
default:
p_err("unsupported kind: %s (%d)",
btf_kind_str(btf_type), btf_type->type);
return -EINVAL;
}
}
return 0;
}
static int btfgen_record_type_relo(struct btfgen_info *info, struct bpf_core_spec *targ_spec)
{
return btfgen_mark_type(info, targ_spec->root_type_id, true);
}
static int btfgen_record_enumval_relo(struct btfgen_info *info, struct bpf_core_spec *targ_spec)
{
return btfgen_mark_type(info, targ_spec->root_type_id, false);
}
static int btfgen_record_reloc(struct btfgen_info *info, struct bpf_core_spec *res)
{
switch (res->relo_kind) {
case BPF_CORE_FIELD_BYTE_OFFSET:
case BPF_CORE_FIELD_BYTE_SIZE:
case BPF_CORE_FIELD_EXISTS:
case BPF_CORE_FIELD_SIGNED:
case BPF_CORE_FIELD_LSHIFT_U64:
case BPF_CORE_FIELD_RSHIFT_U64:
return btfgen_record_field_relo(info, res);
case BPF_CORE_TYPE_ID_LOCAL: /* BPF_CORE_TYPE_ID_LOCAL doesn't require kernel BTF */
return 0;
case BPF_CORE_TYPE_ID_TARGET:
case BPF_CORE_TYPE_EXISTS:
case BPF_CORE_TYPE_SIZE:
return btfgen_record_type_relo(info, res);
case BPF_CORE_ENUMVAL_EXISTS:
case BPF_CORE_ENUMVAL_VALUE:
return btfgen_record_enumval_relo(info, res);
default:
return -EINVAL;
}
}
static struct bpf_core_cand_list *
btfgen_find_cands(const struct btf *local_btf, const struct btf *targ_btf, __u32 local_id)
{
const struct btf_type *local_type;
struct bpf_core_cand_list *cands = NULL;
struct bpf_core_cand local_cand = {};
size_t local_essent_len;
const char *local_name;
int err;
local_cand.btf = local_btf;
local_cand.id = local_id;
local_type = btf__type_by_id(local_btf, local_id);
if (!local_type) {
err = -EINVAL;
goto err_out;
}
local_name = btf__name_by_offset(local_btf, local_type->name_off);
if (!local_name) {
err = -EINVAL;
goto err_out;
}
local_essent_len = bpf_core_essential_name_len(local_name);
cands = calloc(1, sizeof(*cands));
if (!cands)
return NULL;
err = bpf_core_add_cands(&local_cand, local_essent_len, targ_btf, "vmlinux", 1, cands);
if (err)
goto err_out;
return cands;
err_out:
bpf_core_free_cands(cands);
errno = -err;
return NULL;
}
/* Record relocation information for a single BPF object */
static int btfgen_record_obj(struct btfgen_info *info, const char *obj_path)
{
const struct btf_ext_info_sec *sec;
const struct bpf_core_relo *relo;
const struct btf_ext_info *seg;
struct hashmap_entry *entry;
struct hashmap *cand_cache = NULL;
struct btf_ext *btf_ext = NULL;
unsigned int relo_idx;
struct btf *btf = NULL;
size_t i;
int err;
btf = btf__parse(obj_path, &btf_ext);
if (!btf) {
err = -errno;
p_err("failed to parse BPF object '%s': %s", obj_path, strerror(errno));
return err;
}
if (!btf_ext) {
p_err("failed to parse BPF object '%s': section %s not found",
obj_path, BTF_EXT_ELF_SEC);
err = -EINVAL;
goto out;
}
if (btf_ext->core_relo_info.len == 0) {
err = 0;
goto out;
}
cand_cache = hashmap__new(btfgen_hash_fn, btfgen_equal_fn, NULL);
if (IS_ERR(cand_cache)) {
err = PTR_ERR(cand_cache);
goto out;
}
seg = &btf_ext->core_relo_info;
for_each_btf_ext_sec(seg, sec) {
for_each_btf_ext_rec(seg, sec, relo_idx, relo) {
struct bpf_core_spec specs_scratch[3] = {};
struct bpf_core_relo_res targ_res = {};
struct bpf_core_cand_list *cands = NULL;
const void *type_key = u32_as_hash_key(relo->type_id);
const char *sec_name = btf__name_by_offset(btf, sec->sec_name_off);
if (relo->kind != BPF_CORE_TYPE_ID_LOCAL &&
!hashmap__find(cand_cache, type_key, (void **)&cands)) {
cands = btfgen_find_cands(btf, info->src_btf, relo->type_id);
if (!cands) {
err = -errno;
goto out;
}
err = hashmap__set(cand_cache, type_key, cands, NULL, NULL);
if (err)
goto out;
}
err = bpf_core_calc_relo_insn(sec_name, relo, relo_idx, btf, cands,
specs_scratch, &targ_res);
if (err)
goto out;
/* specs_scratch[2] is the target spec */
err = btfgen_record_reloc(info, &specs_scratch[2]);
if (err)
goto out;
}
}
out:
btf__free(btf);
btf_ext__free(btf_ext);
if (!IS_ERR_OR_NULL(cand_cache)) {
hashmap__for_each_entry(cand_cache, entry, i) {
bpf_core_free_cands(entry->value);
}
hashmap__free(cand_cache);
}
return err;
}
static int btfgen_remap_id(__u32 *type_id, void *ctx)
{
unsigned int *ids = ctx;
*type_id = ids[*type_id];
return 0;
}
/* Generate BTF from relocation information previously recorded */
static struct btf *btfgen_get_btf(struct btfgen_info *info)
{
struct btf *btf_new = NULL;
unsigned int *ids = NULL;
unsigned int i, n = btf__type_cnt(info->marked_btf);
int err = 0;
btf_new = btf__new_empty();
if (!btf_new) {
err = -errno;
goto err_out;
}
ids = calloc(n, sizeof(*ids));
if (!ids) {
err = -errno;
goto err_out;
}
/* first pass: add all marked types to btf_new and add their new ids to the ids map */
for (i = 1; i < n; i++) {
const struct btf_type *cloned_type, *type;
const char *name;
int new_id;
cloned_type = btf__type_by_id(info->marked_btf, i);
if (cloned_type->name_off != MARKED)
continue;
type = btf__type_by_id(info->src_btf, i);
/* add members for struct and union */
if (btf_is_composite(type)) {
struct btf_member *cloned_m, *m;
unsigned short vlen;
int idx_src;
name = btf__str_by_offset(info->src_btf, type->name_off);
if (btf_is_struct(type))
err = btf__add_struct(btf_new, name, type->size);
else
err = btf__add_union(btf_new, name, type->size);
if (err < 0)
goto err_out;
new_id = err;
cloned_m = btf_members(cloned_type);
m = btf_members(type);
vlen = btf_vlen(cloned_type);
for (idx_src = 0; idx_src < vlen; idx_src++, cloned_m++, m++) {
/* add only members that are marked as used */
if (cloned_m->name_off != MARKED)
continue;
name = btf__str_by_offset(info->src_btf, m->name_off);
err = btf__add_field(btf_new, name, m->type,
btf_member_bit_offset(cloned_type, idx_src),
btf_member_bitfield_size(cloned_type, idx_src));
if (err < 0)
goto err_out;
}
} else {
err = btf__add_type(btf_new, info->src_btf, type);
if (err < 0)
goto err_out;
new_id = err;
}
/* add ID mapping */
ids[i] = new_id;
}
/* second pass: fix up type ids */
for (i = 1; i < btf__type_cnt(btf_new); i++) {
struct btf_type *btf_type = (struct btf_type *) btf__type_by_id(btf_new, i);
err = btf_type_visit_type_ids(btf_type, btfgen_remap_id, ids);
if (err)
goto err_out;
}
free(ids);
return btf_new;
err_out:
btf__free(btf_new);
free(ids);
errno = -err;
return NULL;
}
/* Create minimized BTF file for a set of BPF objects.
*
* The BTFGen algorithm is divided in two main parts: (1) collect the
* BTF types that are involved in relocations and (2) generate the BTF
* object using the collected types.
*
* In order to collect the types involved in the relocations, we parse
* the BTF and BTF.ext sections of the BPF objects and use
* bpf_core_calc_relo_insn() to get the target specification, this
* indicates how the types and fields are used in a relocation.
*
* Types are recorded in different ways according to the kind of the
* relocation. For field-based relocations only the members that are
* actually used are saved in order to reduce the size of the generated
* BTF file. For type-based relocations empty struct / unions are
* generated and for enum-based relocations the whole type is saved.
*
* The second part of the algorithm generates the BTF object. It creates
* an empty BTF object and fills it with the types recorded in the
* previous step. This function takes care of only adding the structure
* and union members that were marked as used and it also fixes up the
* type IDs on the generated BTF object.
*/
static int minimize_btf(const char *src_btf, const char *dst_btf, const char *objspaths[])
{
struct btfgen_info *info;
struct btf *btf_new = NULL;
int err, i;
info = btfgen_new_info(src_btf);
if (!info) {
err = -errno;
p_err("failed to allocate info structure: %s", strerror(errno));
goto out;
}
for (i = 0; objspaths[i] != NULL; i++) {
err = btfgen_record_obj(info, objspaths[i]);
if (err) {
p_err("error recording relocations for %s: %s", objspaths[i],
strerror(errno));
goto out;
}
}
btf_new = btfgen_get_btf(info);
if (!btf_new) {
err = -errno;
p_err("error generating BTF: %s", strerror(errno));
goto out;
}
err = btf_save_raw(btf_new, dst_btf);
if (err) {
p_err("error saving btf file: %s", strerror(errno));
goto out;
}
out:
btf__free(btf_new);
btfgen_free_info(info);
return err;
}
static int do_min_core_btf(int argc, char **argv)
{
const char *input, *output, **objs;
int i, err;
if (!REQ_ARGS(3)) {
usage();
return -1;
}
input = GET_ARG();
output = GET_ARG();
objs = (const char **) calloc(argc + 1, sizeof(*objs));
if (!objs) {
p_err("failed to allocate array for object names");
return -ENOMEM;
}
i = 0;
while (argc)
objs[i++] = GET_ARG();
err = minimize_btf(input, output, objs);
free(objs);
return err;
}
static const struct cmd cmds[] = {
{ "object", do_object },
{ "skeleton", do_skeleton },
{ "help", do_help },
{ "object", do_object },
{ "skeleton", do_skeleton },
{ "min_core_btf", do_min_core_btf},
{ "help", do_help },
{ 0 }
};

25
tools/bpf/bpftool/main.c
View File

@ -71,6 +71,17 @@ static int do_help(int argc, char **argv)
return 0;
}
#ifndef BPFTOOL_VERSION
/* bpftool's major and minor version numbers are aligned on libbpf's. There is
* an offset of 6 for the version number, because bpftool's version was higher
* than libbpf's when we adopted this scheme. The patch number remains at 0
* for now. Set BPFTOOL_VERSION to override.
*/
#define BPFTOOL_MAJOR_VERSION (LIBBPF_MAJOR_VERSION + 6)
#define BPFTOOL_MINOR_VERSION LIBBPF_MINOR_VERSION
#define BPFTOOL_PATCH_VERSION 0
#endif
static int do_version(int argc, char **argv)
{
#ifdef HAVE_LIBBFD_SUPPORT
@ -88,7 +99,15 @@ static int do_version(int argc, char **argv)
jsonw_start_object(json_wtr); /* root object */
jsonw_name(json_wtr, "version");
#ifdef BPFTOOL_VERSION
jsonw_printf(json_wtr, "\"%s\"", BPFTOOL_VERSION);
#else
jsonw_printf(json_wtr, "\"%d.%d.%d\"", BPFTOOL_MAJOR_VERSION,
BPFTOOL_MINOR_VERSION, BPFTOOL_PATCH_VERSION);
#endif
jsonw_name(json_wtr, "libbpf_version");
jsonw_printf(json_wtr, "\"%d.%d\"",
libbpf_major_version(), libbpf_minor_version());
jsonw_name(json_wtr, "features");
jsonw_start_object(json_wtr); /* features */
@ -101,7 +120,13 @@ static int do_version(int argc, char **argv)
} else {
unsigned int nb_features = 0;
#ifdef BPFTOOL_VERSION
printf("%s v%s\n", bin_name, BPFTOOL_VERSION);
#else
printf("%s v%d.%d.%d\n", bin_name, BPFTOOL_MAJOR_VERSION,
BPFTOOL_MINOR_VERSION, BPFTOOL_PATCH_VERSION);
#endif
printf("using libbpf %s\n", libbpf_version_string());
printf("features:");
if (has_libbfd) {
printf(" libbfd");

33
tools/bpf/bpftool/map.c
View File

@ -805,29 +805,30 @@ static int maps_have_btf(int *fds, int nb_fds)
static struct btf *btf_vmlinux;
static struct btf *get_map_kv_btf(const struct bpf_map_info *info)
static int get_map_kv_btf(const struct bpf_map_info *info, struct btf **btf)
{
struct btf *btf = NULL;
int err = 0;
if (info->btf_vmlinux_value_type_id) {
if (!btf_vmlinux) {
btf_vmlinux = libbpf_find_kernel_btf();
if (libbpf_get_error(btf_vmlinux))
err = libbpf_get_error(btf_vmlinux);
if (err) {
p_err("failed to get kernel btf");
return err;
}
}
return btf_vmlinux;
*btf = btf_vmlinux;
} else if (info->btf_value_type_id) {
int err;
btf = btf__load_from_kernel_by_id(info->btf_id);
err = libbpf_get_error(btf);
if (err) {
*btf = btf__load_from_kernel_by_id(info->btf_id);
err = libbpf_get_error(*btf);
if (err)
p_err("failed to get btf");
btf = ERR_PTR(err);
}
} else {
*btf = NULL;
}
return btf;
return err;
}
static void free_map_kv_btf(struct btf *btf)
@ -862,8 +863,7 @@ map_dump(int fd, struct bpf_map_info *info, json_writer_t *wtr,
prev_key = NULL;
if (wtr) {
btf = get_map_kv_btf(info);
err = libbpf_get_error(btf);
err = get_map_kv_btf(info, &btf);
if (err) {
goto exit_free;
}
@ -1054,11 +1054,8 @@ static void print_key_value(struct bpf_map_info *info, void *key,
json_writer_t *btf_wtr;
struct btf *btf;
btf = btf__load_from_kernel_by_id(info->btf_id);
if (libbpf_get_error(btf)) {
p_err("failed to get btf");
if (get_map_kv_btf(info, &btf))
return;
}
if (json_output) {
print_entry_json(info, key, value, btf);

15
tools/lib/bpf/gen_loader.c
View File

@ -1043,18 +1043,27 @@ void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *pvalue,
value = add_data(gen, pvalue, value_size);
key = add_data(gen, &zero, sizeof(zero));
/* if (map_desc[map_idx].initial_value)
* copy_from_user(value, initial_value, value_size);
/* if (map_desc[map_idx].initial_value) {
* if (ctx->flags & BPF_SKEL_KERNEL)
* bpf_probe_read_kernel(value, value_size, initial_value);
* else
* bpf_copy_from_user(value, value_size, initial_value);
* }
*/
emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_6,
sizeof(struct bpf_loader_ctx) +
sizeof(struct bpf_map_desc) * map_idx +
offsetof(struct bpf_map_desc, initial_value)));
emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_3, 0, 4));
emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_3, 0, 8));
emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
0, 0, 0, value));
emit(gen, BPF_MOV64_IMM(BPF_REG_2, value_size));
emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6,
offsetof(struct bpf_loader_ctx, flags)));
emit(gen, BPF_JMP_IMM(BPF_JSET, BPF_REG_0, BPF_SKEL_KERNEL, 2));
emit(gen, BPF_EMIT_CALL(BPF_FUNC_copy_from_user));
emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 1));
emit(gen, BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel));
map_update_attr = add_data(gen, &attr, attr_size);
move_blob2blob(gen, attr_field(map_update_attr, map_fd), 4,

88
tools/lib/bpf/libbpf.c
View File

@ -5192,18 +5192,21 @@ size_t bpf_core_essential_name_len(const char *name)
return n;
}
static void bpf_core_free_cands(struct bpf_core_cand_list *cands)
void bpf_core_free_cands(struct bpf_core_cand_list *cands)
{
if (!cands)
return;
free(cands->cands);
free(cands);
}
static int bpf_core_add_cands(struct bpf_core_cand *local_cand,
size_t local_essent_len,
const struct btf *targ_btf,
const char *targ_btf_name,
int targ_start_id,
struct bpf_core_cand_list *cands)
int bpf_core_add_cands(struct bpf_core_cand *local_cand,
size_t local_essent_len,
const struct btf *targ_btf,
const char *targ_btf_name,
int targ_start_id,
struct bpf_core_cand_list *cands)
{
struct bpf_core_cand *new_cands, *cand;
const struct btf_type *t, *local_t;
@ -5530,11 +5533,12 @@ static int record_relo_core(struct bpf_program *prog,
return 0;
}
static int bpf_core_apply_relo(struct bpf_program *prog,
const struct bpf_core_relo *relo,
int relo_idx,
const struct btf *local_btf,
struct hashmap *cand_cache)
static int bpf_core_resolve_relo(struct bpf_program *prog,
const struct bpf_core_relo *relo,
int relo_idx,
const struct btf *local_btf,
struct hashmap *cand_cache,
struct bpf_core_relo_res *targ_res)
{
struct bpf_core_spec specs_scratch[3] = {};
const void *type_key = u32_as_hash_key(relo->type_id);
@ -5543,20 +5547,7 @@ static int bpf_core_apply_relo(struct bpf_program *prog,
const struct btf_type *local_type;
const char *local_name;
__u32 local_id = relo->type_id;
struct bpf_insn *insn;
int insn_idx, err;
if (relo->insn_off % BPF_INSN_SZ)
return -EINVAL;
insn_idx = relo->insn_off / BPF_INSN_SZ;
/* adjust insn_idx from section frame of reference to the local
* program's frame of reference; (sub-)program code is not yet
* relocated, so it's enough to just subtract in-section offset
*/
insn_idx = insn_idx - prog->sec_insn_off;
if (insn_idx >= prog->insns_cnt)
return -EINVAL;
insn = &prog->insns[insn_idx];
int err;
local_type = btf__type_by_id(local_btf, local_id);
if (!local_type)
@ -5566,15 +5557,6 @@ static int bpf_core_apply_relo(struct bpf_program *prog,
if (!local_name)
return -EINVAL;
if (prog->obj->gen_loader) {
const char *spec_str = btf__name_by_offset(local_btf, relo->access_str_off);
pr_debug("record_relo_core: prog %td insn[%d] %s %s %s final insn_idx %d\n",
prog - prog->obj->programs, relo->insn_off / 8,
btf_kind_str(local_type), local_name, spec_str, insn_idx);
return record_relo_core(prog, relo, insn_idx);
}
if (relo->kind != BPF_CORE_TYPE_ID_LOCAL &&
!hashmap__find(cand_cache, type_key, (void **)&cands)) {
cands = bpf_core_find_cands(prog->obj, local_btf, local_id);
@ -5591,19 +5573,21 @@ static int bpf_core_apply_relo(struct bpf_program *prog,
}
}
return bpf_core_apply_relo_insn(prog_name, insn, insn_idx, relo,
relo_idx, local_btf, cands, specs_scratch);
return bpf_core_calc_relo_insn(prog_name, relo, relo_idx, local_btf, cands, specs_scratch,
targ_res);
}
static int
bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
{
const struct btf_ext_info_sec *sec;
struct bpf_core_relo_res targ_res;
const struct bpf_core_relo *rec;
const struct btf_ext_info *seg;
struct hashmap_entry *entry;
struct hashmap *cand_cache = NULL;
struct bpf_program *prog;
struct bpf_insn *insn;
const char *sec_name;
int i, err = 0, insn_idx, sec_idx;
@ -5654,6 +5638,8 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
sec_name, sec->num_info);
for_each_btf_ext_rec(seg, sec, i, rec) {
if (rec->insn_off % BPF_INSN_SZ)
return -EINVAL;
insn_idx = rec->insn_off / BPF_INSN_SZ;
prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx);
if (!prog) {
@ -5668,12 +5654,38 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
if (!prog->load)
continue;
err = bpf_core_apply_relo(prog, rec, i, obj->btf, cand_cache);
/* adjust insn_idx from section frame of reference to the local
* program's frame of reference; (sub-)program code is not yet
* relocated, so it's enough to just subtract in-section offset
*/
insn_idx = insn_idx - prog->sec_insn_off;
if (insn_idx >= prog->insns_cnt)
return -EINVAL;
insn = &prog->insns[insn_idx];
if (prog->obj->gen_loader) {
err = record_relo_core(prog, rec, insn_idx);
if (err) {
pr_warn("prog '%s': relo #%d: failed to record relocation: %d\n",
prog->name, i, err);
goto out;
}
continue;
}
err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res);
if (err) {
pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
prog->name, i, err);
goto out;
}
err = bpf_core_patch_insn(prog->name, insn, insn_idx, rec, i, &targ_res);
if (err) {
pr_warn("prog '%s': relo #%d: failed to patch insn #%u: %d\n",
prog->name, i, insn_idx, err);
goto out;
}
}
}

2
tools/lib/bpf/libbpf.map
View File

@ -438,4 +438,4 @@ LIBBPF_0.7.0 {
libbpf_probe_bpf_map_type;
libbpf_probe_bpf_prog_type;
libbpf_set_memlock_rlim_max;
};
} LIBBPF_0.6.0;

9
tools/lib/bpf/libbpf_internal.h
View File

@ -529,4 +529,13 @@ static inline int ensure_good_fd(int fd)
return fd;
}
/* The following two functions are exposed to bpftool */
int bpf_core_add_cands(struct bpf_core_cand *local_cand,
size_t local_essent_len,
const struct btf *targ_btf,
const char *targ_btf_name,
int targ_start_id,
struct bpf_core_cand_list *cands);
void bpf_core_free_cands(struct bpf_core_cand_list *cands);
#endif /* __LIBBPF_LIBBPF_INTERNAL_H */

63
tools/lib/bpf/netlink.c
View File

@ -87,29 +87,75 @@ enum {
NL_DONE,
};
static int netlink_recvmsg(int sock, struct msghdr *mhdr, int flags)
{
int len;
do {
len = recvmsg(sock, mhdr, flags);
} while (len < 0 && (errno == EINTR || errno == EAGAIN));
if (len < 0)
return -errno;
return len;
}
static int alloc_iov(struct iovec *iov, int len)
{
void *nbuf;
nbuf = realloc(iov->iov_base, len);
if (!nbuf)
return -ENOMEM;
iov->iov_base = nbuf;
iov->iov_len = len;
return 0;
}
static int libbpf_netlink_recv(int sock, __u32 nl_pid, int seq,
__dump_nlmsg_t _fn, libbpf_dump_nlmsg_t fn,
void *cookie)
{
struct iovec iov = {};
struct msghdr mhdr = {
.msg_iov = &iov,
.msg_iovlen = 1,
};
bool multipart = true;
struct nlmsgerr *err;
struct nlmsghdr *nh;
char buf[4096];
int len, ret;
ret = alloc_iov(&iov, 4096);
if (ret)
goto done;
while (multipart) {
start:
multipart = false;
len = recv(sock, buf, sizeof(buf), 0);
len = netlink_recvmsg(sock, &mhdr, MSG_PEEK | MSG_TRUNC);
if (len < 0) {
ret = -errno;
ret = len;
goto done;
}
if (len > iov.iov_len) {
ret = alloc_iov(&iov, len);
if (ret)
goto done;
}
len = netlink_recvmsg(sock, &mhdr, 0);
if (len < 0) {
ret = len;
goto done;
}
if (len == 0)
break;
for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
for (nh = (struct nlmsghdr *)iov.iov_base; NLMSG_OK(nh, len);
nh = NLMSG_NEXT(nh, len)) {
if (nh->nlmsg_pid != nl_pid) {
ret = -LIBBPF_ERRNO__WRNGPID;
@ -130,7 +176,8 @@ start:
libbpf_nla_dump_errormsg(nh);
goto done;
case NLMSG_DONE:
return 0;
ret = 0;
goto done;
default:
break;
}
@ -142,15 +189,17 @@ start:
case NL_NEXT:
goto start;
case NL_DONE:
return 0;
ret = 0;
goto done;
default:
return ret;
goto done;
}
}
}
}
ret = 0;
done:
free(iov.iov_base);
return ret;
}

79
tools/lib/bpf/relo_core.c
View File

@ -775,31 +775,6 @@ static int bpf_core_calc_enumval_relo(const struct bpf_core_relo *relo,
return 0;
}
struct bpf_core_relo_res
{
/* expected value in the instruction, unless validate == false */
__u32 orig_val;
/* new value that needs to be patched up to */
__u32 new_val;
/* relocation unsuccessful, poison instruction, but don't fail load */
bool poison;
/* some relocations can't be validated against orig_val */
bool validate;
/* for field byte offset relocations or the forms:
* *(T *)(rX + <off>) = rY
* rX = *(T *)(rY + <off>),
* we remember original and resolved field size to adjust direct
* memory loads of pointers and integers; this is necessary for 32-bit
* host kernel architectures, but also allows to automatically
* relocate fields that were resized from, e.g., u32 to u64, etc.
*/
bool fail_memsz_adjust;
__u32 orig_sz;
__u32 orig_type_id;
__u32 new_sz;
__u32 new_type_id;
};
/* Calculate original and target relocation values, given local and target
* specs and relocation kind. These values are calculated for each candidate.
* If there are multiple candidates, resulting values should all be consistent
@ -951,9 +926,9 @@ static int insn_bytes_to_bpf_size(__u32 sz)
* 5. *(T *)(rX + <off>) = rY, where T is one of {u8, u16, u32, u64};
* 6. *(T *)(rX + <off>) = <imm>, where T is one of {u8, u16, u32, u64}.
*/
static int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn,
int insn_idx, const struct bpf_core_relo *relo,
int relo_idx, const struct bpf_core_relo_res *res)
int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn,
int insn_idx, const struct bpf_core_relo *relo,
int relo_idx, const struct bpf_core_relo_res *res)
{
__u32 orig_val, new_val;
__u8 class;
@ -1128,7 +1103,7 @@ static void bpf_core_dump_spec(const char *prog_name, int level, const struct bp
}
/*
* CO-RE relocate single instruction.
* Calculate CO-RE relocation target result.
*
* The outline and important points of the algorithm:
* 1. For given local type, find corresponding candidate target types.
@ -1177,18 +1152,18 @@ static void bpf_core_dump_spec(const char *prog_name, int level, const struct bp
* between multiple relocations for the same type ID and is updated as some
* of the candidates are pruned due to structural incompatibility.
*/
int bpf_core_apply_relo_insn(const char *prog_name, struct bpf_insn *insn,
int insn_idx,
const struct bpf_core_relo *relo,
int relo_idx,
const struct btf *local_btf,
struct bpf_core_cand_list *cands,
struct bpf_core_spec *specs_scratch)
int bpf_core_calc_relo_insn(const char *prog_name,
const struct bpf_core_relo *relo,
int relo_idx,
const struct btf *local_btf,
struct bpf_core_cand_list *cands,
struct bpf_core_spec *specs_scratch,
struct bpf_core_relo_res *targ_res)
{
struct bpf_core_spec *local_spec = &specs_scratch[0];
struct bpf_core_spec *cand_spec = &specs_scratch[1];
struct bpf_core_spec *targ_spec = &specs_scratch[2];
struct bpf_core_relo_res cand_res, targ_res;
struct bpf_core_relo_res cand_res;
const struct btf_type *local_type;
const char *local_name;
__u32 local_id;
@ -1223,12 +1198,12 @@ int bpf_core_apply_relo_insn(const char *prog_name, struct bpf_insn *insn,
/* TYPE_ID_LOCAL relo is special and doesn't need candidate search */
if (relo->kind == BPF_CORE_TYPE_ID_LOCAL) {
/* bpf_insn's imm value could get out of sync during linking */
memset(&targ_res, 0, sizeof(targ_res));
targ_res.validate = false;
targ_res.poison = false;
targ_res.orig_val = local_spec->root_type_id;
targ_res.new_val = local_spec->root_type_id;
goto patch_insn;
memset(targ_res, 0, sizeof(*targ_res));
targ_res->validate = false;
targ_res->poison = false;
targ_res->orig_val = local_spec->root_type_id;
targ_res->new_val = local_spec->root_type_id;
return 0;
}
/* libbpf doesn't support candidate search for anonymous types */
@ -1262,7 +1237,7 @@ int bpf_core_apply_relo_insn(const char *prog_name, struct bpf_insn *insn,
return err;
if (j == 0) {
targ_res = cand_res;
*targ_res = cand_res;
*targ_spec = *cand_spec;
} else if (cand_spec->bit_offset != targ_spec->bit_offset) {
/* if there are many field relo candidates, they
@ -1272,7 +1247,8 @@ int bpf_core_apply_relo_insn(const char *prog_name, struct bpf_insn *insn,
prog_name, relo_idx, cand_spec->bit_offset,
targ_spec->bit_offset);
return -EINVAL;
} else if (cand_res.poison != targ_res.poison || cand_res.new_val != targ_res.new_val) {
} else if (cand_res.poison != targ_res->poison ||
cand_res.new_val != targ_res->new_val) {
/* all candidates should result in the same relocation
* decision and value, otherwise it's dangerous to
* proceed due to ambiguity
@ -1280,7 +1256,7 @@ int bpf_core_apply_relo_insn(const char *prog_name, struct bpf_insn *insn,
pr_warn("prog '%s': relo #%d: relocation decision ambiguity: %s %u != %s %u\n",
prog_name, relo_idx,
cand_res.poison ? "failure" : "success", cand_res.new_val,
targ_res.poison ? "failure" : "success", targ_res.new_val);
targ_res->poison ? "failure" : "success", targ_res->new_val);
return -EINVAL;
}
@ -1314,19 +1290,10 @@ int bpf_core_apply_relo_insn(const char *prog_name, struct bpf_insn *insn,
prog_name, relo_idx);
/* calculate single target relo result explicitly */
err = bpf_core_calc_relo(prog_name, relo, relo_idx, local_spec, NULL, &targ_res);
err = bpf_core_calc_relo(prog_name, relo, relo_idx, local_spec, NULL, targ_res);
if (err)
return err;
}
patch_insn:
/* bpf_core_patch_insn() should know how to handle missing targ_spec */
err = bpf_core_patch_insn(prog_name, insn, insn_idx, relo, relo_idx, &targ_res);
if (err) {
pr_warn("prog '%s': relo #%d: failed to patch insn #%u: %d\n",
prog_name, relo_idx, relo->insn_off / 8, err);
return -EINVAL;
}
return 0;
}

42
tools/lib/bpf/relo_core.h
View File

@ -44,14 +44,44 @@ struct bpf_core_spec {
__u32 bit_offset;
};
int bpf_core_apply_relo_insn(const char *prog_name,
struct bpf_insn *insn, int insn_idx,
const struct bpf_core_relo *relo, int relo_idx,
const struct btf *local_btf,
struct bpf_core_cand_list *cands,
struct bpf_core_spec *specs_scratch);
struct bpf_core_relo_res {
/* expected value in the instruction, unless validate == false */
__u32 orig_val;
/* new value that needs to be patched up to */
__u32 new_val;
/* relocation unsuccessful, poison instruction, but don't fail load */
bool poison;
/* some relocations can't be validated against orig_val */
bool validate;
/* for field byte offset relocations or the forms:
* *(T *)(rX + <off>) = rY
* rX = *(T *)(rY + <off>),
* we remember original and resolved field size to adjust direct
* memory loads of pointers and integers; this is necessary for 32-bit
* host kernel architectures, but also allows to automatically
* relocate fields that were resized from, e.g., u32 to u64, etc.
*/
bool fail_memsz_adjust;
__u32 orig_sz;
__u32 orig_type_id;
__u32 new_sz;
__u32 new_type_id;
};
int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
const struct btf *targ_btf, __u32 targ_id);
size_t bpf_core_essential_name_len(const char *name);
int bpf_core_calc_relo_insn(const char *prog_name,
const struct bpf_core_relo *relo, int relo_idx,
const struct btf *local_btf,
struct bpf_core_cand_list *cands,
struct bpf_core_spec *specs_scratch,
struct bpf_core_relo_res *targ_res);
int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn,
int insn_idx, const struct bpf_core_relo *relo,
int relo_idx, const struct bpf_core_relo_res *res);
#endif

185
tools/lib/bpf/skel_internal.h
View File

@ -3,9 +3,19 @@
#ifndef __SKEL_INTERNAL_H
#define __SKEL_INTERNAL_H
#ifdef __KERNEL__
#include <linux/fdtable.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/slab.h>
#include <linux/bpf.h>
#else
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/mman.h>
#include <stdlib.h>
#include "bpf.h"
#endif
#ifndef __NR_bpf
# if defined(__mips__) && defined(_ABIO32)
@ -25,24 +35,23 @@
* requested during loader program generation.
*/
struct bpf_map_desc {
union {
/* input for the loader prog */
struct {
__aligned_u64 initial_value;
__u32 max_entries;
};
/* output of the loader prog */
struct {
int map_fd;
};
};
/* output of the loader prog */
int map_fd;
/* input for the loader prog */
__u32 max_entries;
__aligned_u64 initial_value;
};
struct bpf_prog_desc {
int prog_fd;
};
enum {
BPF_SKEL_KERNEL = (1ULL << 0),
};
struct bpf_loader_ctx {
size_t sz;
__u32 sz;
__u32 flags;
__u32 log_level;
__u32 log_size;
__u64 log_buf;
@ -57,12 +66,144 @@ struct bpf_load_and_run_opts {
const char *errstr;
};
long bpf_sys_bpf(__u32 cmd, void *attr, __u32 attr_size);
static inline int skel_sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
unsigned int size)
{
#ifdef __KERNEL__
return bpf_sys_bpf(cmd, attr, size);
#else
return syscall(__NR_bpf, cmd, attr, size);
#endif
}
#ifdef __KERNEL__
static inline int close(int fd)
{
return close_fd(fd);
}
static inline void *skel_alloc(size_t size)
{
struct bpf_loader_ctx *ctx = kzalloc(size, GFP_KERNEL);
if (!ctx)
return NULL;
ctx->flags |= BPF_SKEL_KERNEL;
return ctx;
}
static inline void skel_free(const void *p)
{
kfree(p);
}
/* skel->bss/rodata maps are populated the following way:
*
* For kernel use:
* skel_prep_map_data() allocates kernel memory that kernel module can directly access.
* Generated lskel stores the pointer in skel->rodata and in skel->maps.rodata.initial_value.
* The loader program will perform probe_read_kernel() from maps.rodata.initial_value.
* skel_finalize_map_data() sets skel->rodata to point to actual value in a bpf map and
* does maps.rodata.initial_value = ~0ULL to signal skel_free_map_data() that kvfree
* is not nessary.
*
* For user space:
* skel_prep_map_data() mmaps anon memory into skel->rodata that can be accessed directly.
* Generated lskel stores the pointer in skel->rodata and in skel->maps.rodata.initial_value.
* The loader program will perform copy_from_user() from maps.rodata.initial_value.
* skel_finalize_map_data() remaps bpf array map value from the kernel memory into
* skel->rodata address.
*
* The "bpftool gen skeleton -L" command generates lskel.h that is suitable for
* both kernel and user space. The generated loader program does
* either bpf_probe_read_kernel() or bpf_copy_from_user() from initial_value
* depending on bpf_loader_ctx->flags.
*/
static inline void skel_free_map_data(void *p, __u64 addr, size_t sz)
{
if (addr != ~0ULL)
kvfree(p);
/* When addr == ~0ULL the 'p' points to
* ((struct bpf_array *)map)->value. See skel_finalize_map_data.
*/
}
static inline void *skel_prep_map_data(const void *val, size_t mmap_sz, size_t val_sz)
{
void *addr;
addr = kvmalloc(val_sz, GFP_KERNEL);
if (!addr)
return NULL;
memcpy(addr, val, val_sz);
return addr;
}
static inline void *skel_finalize_map_data(__u64 *init_val, size_t mmap_sz, int flags, int fd)
{
struct bpf_map *map;
void *addr = NULL;
kvfree((void *) (long) *init_val);
*init_val = ~0ULL;
/* At this point bpf_load_and_run() finished without error and
* 'fd' is a valid bpf map FD. All sanity checks below should succeed.
*/
map = bpf_map_get(fd);
if (IS_ERR(map))
return NULL;
if (map->map_type != BPF_MAP_TYPE_ARRAY)
goto out;
addr = ((struct bpf_array *)map)->value;
/* the addr stays valid, since FD is not closed */
out:
bpf_map_put(map);
return addr;
}
#else
static inline void *skel_alloc(size_t size)
{
return calloc(1, size);
}
static inline void skel_free(void *p)
{
free(p);
}
static inline void skel_free_map_data(void *p, __u64 addr, size_t sz)
{
munmap(p, sz);
}
static inline void *skel_prep_map_data(const void *val, size_t mmap_sz, size_t val_sz)
{
void *addr;
addr = mmap(NULL, mmap_sz, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_ANONYMOUS, -1, 0);
if (addr == (void *) -1)
return NULL;
memcpy(addr, val, val_sz);
return addr;
}
static inline void *skel_finalize_map_data(__u64 *init_val, size_t mmap_sz, int flags, int fd)
{
void *addr;
addr = mmap((void *) (long) *init_val, mmap_sz, flags, MAP_SHARED | MAP_FIXED, fd, 0);
if (addr == (void *) -1)
return NULL;
return addr;
}
#endif
static inline int skel_closenz(int fd)
{
if (fd > 0)
@ -136,22 +277,28 @@ static inline int skel_link_create(int prog_fd, int target_fd,
return skel_sys_bpf(BPF_LINK_CREATE, &attr, attr_sz);
}
#ifdef __KERNEL__
#define set_err
#else
#define set_err err = -errno
#endif
static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts)
{
int map_fd = -1, prog_fd = -1, key = 0, err;
union bpf_attr attr;
map_fd = skel_map_create(BPF_MAP_TYPE_ARRAY, "__loader.map", 4, opts->data_sz, 1);
err = map_fd = skel_map_create(BPF_MAP_TYPE_ARRAY, "__loader.map", 4, opts->data_sz, 1);
if (map_fd < 0) {
opts->errstr = "failed to create loader map";
err = -errno;
set_err;
goto out;
}
err = skel_map_update_elem(map_fd, &key, opts->data, 0);
if (err < 0) {
opts->errstr = "failed to update loader map";
err = -errno;
set_err;
goto out;
}
@ -166,10 +313,10 @@ static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts)
attr.log_size = opts->ctx->log_size;
attr.log_buf = opts->ctx->log_buf;
attr.prog_flags = BPF_F_SLEEPABLE;
prog_fd = skel_sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
err = prog_fd = skel_sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
if (prog_fd < 0) {
opts->errstr = "failed to load loader prog";
err = -errno;
set_err;
goto out;
}
@ -181,10 +328,12 @@ static inline int bpf_load_and_run(struct bpf_load_and_run_opts *opts)
if (err < 0 || (int)attr.test.retval < 0) {
opts->errstr = "failed to execute loader prog";
if (err < 0) {
err = -errno;
set_err;
} else {
err = (int)attr.test.retval;
#ifndef __KERNEL__
errno = -err;
#endif
}
goto out;
}

2
tools/testing/selftests/bpf/prog_tests/btf.c
View File

@ -6556,7 +6556,7 @@ done:
static void do_test_info_raw(unsigned int test_num)
{
const struct prog_info_raw_test *test = &info_raw_tests[test_num - 1];
unsigned int raw_btf_size, linfo_str_off, linfo_size;
unsigned int raw_btf_size, linfo_str_off, linfo_size = 0;
int btf_fd = -1, prog_fd = -1, err = 0;
void *raw_btf, *patched_linfo = NULL;
const char *ret_next_str;

52
tools/testing/selftests/bpf/prog_tests/core_reloc.c
View File

@ -2,6 +2,7 @@
#include <test_progs.h>
#include "progs/core_reloc_types.h"
#include "bpf_testmod/bpf_testmod.h"
#include <linux/limits.h>
#include <sys/mman.h>
#include <sys/syscall.h>
#include <bpf/btf.h>
@ -836,13 +837,27 @@ static size_t roundup_page(size_t sz)
return (sz + page_size - 1) / page_size * page_size;
}
void test_core_reloc(void)
static int run_btfgen(const char *src_btf, const char *dst_btf, const char *objpath)
{
char command[4096];
int n;
n = snprintf(command, sizeof(command),
"./tools/build/bpftool/bpftool gen min_core_btf %s %s %s",
src_btf, dst_btf, objpath);
if (n < 0 || n >= sizeof(command))
return -1;
return system(command);
}
static void run_core_reloc_tests(bool use_btfgen)
{
const size_t mmap_sz = roundup_page(sizeof(struct data));
DECLARE_LIBBPF_OPTS(bpf_object_open_opts, open_opts);
struct core_reloc_test_case *test_case;
const char *tp_name, *probe_name;
int err, i, equal;
int err, i, equal, fd;
struct bpf_link *link = NULL;
struct bpf_map *data_map;
struct bpf_program *prog;
@ -854,6 +869,7 @@ void test_core_reloc(void)
my_pid_tgid = getpid() | ((uint64_t)syscall(SYS_gettid) << 32);
for (i = 0; i < ARRAY_SIZE(test_cases); i++) {
char btf_file[] = "/tmp/core_reloc.btf.XXXXXX";
test_case = &test_cases[i];
if (!test__start_subtest(test_case->case_name))
continue;
@ -863,6 +879,25 @@ void test_core_reloc(void)
continue;
}
/* generate a "minimal" BTF file and use it as source */
if (use_btfgen) {
if (!test_case->btf_src_file || test_case->fails) {
test__skip();
continue;
}
fd = mkstemp(btf_file);
if (!ASSERT_GE(fd, 0, "btf_tmp"))
continue;
close(fd); /* we only need the path */
err = run_btfgen(test_case->btf_src_file, btf_file,
test_case->bpf_obj_file);
if (!ASSERT_OK(err, "run_btfgen"))
continue;
test_case->btf_src_file = btf_file;
}
if (test_case->setup) {
err = test_case->setup(test_case);
if (CHECK(err, "test_setup", "test #%d setup failed: %d\n", i, err))
@ -872,7 +907,7 @@ void test_core_reloc(void)
if (test_case->btf_src_file) {
err = access(test_case->btf_src_file, R_OK);
if (!ASSERT_OK(err, "btf_src_file"))
goto cleanup;
continue;
}
open_opts.btf_custom_path = test_case->btf_src_file;
@ -954,8 +989,19 @@ cleanup:
CHECK_FAIL(munmap(mmap_data, mmap_sz));
mmap_data = NULL;
}
remove(btf_file);
bpf_link__destroy(link);
link = NULL;
bpf_object__close(obj);
}
}
void test_core_reloc(void)
{
run_core_reloc_tests(false);
}
void test_core_btfgen(void)
{
run_core_reloc_tests(true);
}

2
tools/testing/selftests/bpf/prog_tests/tc_redirect.c
View File

@ -140,7 +140,7 @@ static struct nstoken *open_netns(const char *name)
int err;
struct nstoken *token;
token = malloc(sizeof(struct nstoken));
token = calloc(1, sizeof(struct nstoken));
if (!ASSERT_OK_PTR(token, "malloc token"))
return NULL;

38
tools/testing/selftests/bpf/prog_tests/xdp_adjust_frags.c
View File

@ -5,11 +5,12 @@
static void test_xdp_update_frags(void)
{
const char *file = "./test_xdp_update_frags.o";
int err, prog_fd, max_skb_frags, buf_size, num;
struct bpf_program *prog;
struct bpf_object *obj;
int err, prog_fd;
__u32 *offset;
__u8 *buf;
FILE *f;
LIBBPF_OPTS(bpf_test_run_opts, topts);
obj = bpf_object__open(file);
@ -99,6 +100,41 @@ static void test_xdp_update_frags(void)
ASSERT_EQ(buf[7621], 0xbb, "xdp_update_frag buf[7621]");
free(buf);
/* test_xdp_update_frags: unsupported buffer size */
f = fopen("/proc/sys/net/core/max_skb_frags", "r");
if (!ASSERT_OK_PTR(f, "max_skb_frag file pointer"))
goto out;
num = fscanf(f, "%d", &max_skb_frags);
fclose(f);
if (!ASSERT_EQ(num, 1, "max_skb_frags read failed"))
goto out;
/* xdp_buff linear area size is always set to 4096 in the
* bpf_prog_test_run_xdp routine.
*/
buf_size = 4096 + (max_skb_frags + 1) * sysconf(_SC_PAGE_SIZE);
buf = malloc(buf_size);
if (!ASSERT_OK_PTR(buf, "alloc buf"))
goto out;
memset(buf, 0, buf_size);
offset = (__u32 *)buf;
*offset = 16;
buf[*offset] = 0xaa;
buf[*offset + 15] = 0xaa;
topts.data_in = buf;
topts.data_out = buf;
topts.data_size_in = buf_size;
topts.data_size_out = buf_size;
err = bpf_prog_test_run_opts(prog_fd, &topts);
ASSERT_EQ(err, -ENOMEM,
"unsupported buf size, possible non-default /proc/sys/net/core/max_skb_flags?");
free(buf);
out:
bpf_object__close(obj);
}

87
tools/testing/selftests/bpf/test_cpp.cpp
View File

@ -5,18 +5,100 @@
#include <bpf/btf.h>
#include "test_core_extern.skel.h"
/* do nothing, just make sure we can link successfully */
template <typename T>
class Skeleton {
private:
T *skel;
public:
Skeleton(): skel(nullptr) { }
~Skeleton() { if (skel) T::destroy(skel); }
int open(const struct bpf_object_open_opts *opts = nullptr)
{
int err;
if (skel)
return -EBUSY;
skel = T::open(opts);
err = libbpf_get_error(skel);
if (err) {
skel = nullptr;
return err;
}
return 0;
}
int load() { return T::load(skel); }
int attach() { return T::attach(skel); }
void detach() { return T::detach(skel); }
const T* operator->() const { return skel; }
T* operator->() { return skel; }
const T *get() const { return skel; }
};
static void dump_printf(void *ctx, const char *fmt, va_list args)
{
}
static void try_skeleton_template()
{
Skeleton<test_core_extern> skel;
std::string prog_name;
int err;
LIBBPF_OPTS(bpf_object_open_opts, opts);
err = skel.open(&opts);
if (err) {
fprintf(stderr, "Skeleton open failed: %d\n", err);
return;
}
skel->data->kern_ver = 123;
skel->data->int_val = skel->data->ushort_val;
err = skel.load();
if (err) {
fprintf(stderr, "Skeleton load failed: %d\n", err);
return;
}
if (!skel->kconfig->CONFIG_BPF_SYSCALL)
fprintf(stderr, "Seems like CONFIG_BPF_SYSCALL isn't set?!\n");
err = skel.attach();
if (err) {
fprintf(stderr, "Skeleton attach failed: %d\n", err);
return;
}
prog_name = bpf_program__name(skel->progs.handle_sys_enter);
if (prog_name != "handle_sys_enter")
fprintf(stderr, "Unexpected program name: %s\n", prog_name.c_str());
bpf_link__destroy(skel->links.handle_sys_enter);
skel->links.handle_sys_enter = bpf_program__attach(skel->progs.handle_sys_enter);
skel.detach();
/* destructor will destory underlying skeleton */
}
int main(int argc, char *argv[])
{
struct btf_dump_opts opts = { };
struct test_core_extern *skel;
struct btf *btf;
try_skeleton_template();
/* libbpf.h */
libbpf_set_print(NULL);
@ -25,7 +107,8 @@ int main(int argc, char *argv[])
/* btf.h */
btf = btf__new(NULL, 0);
btf_dump__new(btf, dump_printf, nullptr, &opts);
if (!libbpf_get_error(btf))
btf_dump__new(btf, dump_printf, nullptr, &opts);
/* BPF skeleton */
skel = test_core_extern__open_and_load();

2
tools/testing/selftests/bpf/vmtest.sh
View File

@ -241,7 +241,7 @@ EOF
-nodefaults \
-display none \
-serial mon:stdio \
"${qemu_flags[@]}" \
"${QEMU_FLAGS[@]}" \
-enable-kvm \
-m 4G \
-drive file="${rootfs_img}",format=raw,index=1,media=disk,if=virtio,cache=none \