mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-08-20 14:16:02 +00:00
Code Issues Releases Wiki Activity

perf llvm: Pass LINUX_VERSION_CODE to BPF program when compiling

Browse source 
Arnaldo suggests to make LINUX_VERSION_CODE works like __func__ and
__FILE__ so user don't need to care setting right linux version too
much. In this patch, perf llvm transfers LINUX_VERSION_CODE macro
through clang cmdline.

[1] http://lkml.kernel.org/r/20151029223744.GK2923@kernel.org

Committer notes:

Before, forgetting to update the version:

  # uname -r
  4.3.0-rc1+
  # cat bpf.c
  __attribute__((section("fork=_do_fork"), used))
  int fork(void *ctx)
  {
          return 1;
  }

  char _license[] __attribute__((section("license"), used)) = "GPL";
  int _version __attribute__((section("version"), used)) = 0x40200;
  #
  # perf record -e bpf.c sleep 1
  event syntax error: 'bpf.c'
                       \___ Invalid argument: Are you root and runing a CONFIG_BPF_SYSCALL kernel?

  (add -v to see detail)
  Run 'perf list' for a list of valid events

   Usage: perf record [<options>] [<command>]
      or: perf record [<options>] -- <command> [<options>]

      -e, --event <event>   event selector. use 'perf list' to list available events
 #

After:

  # grep version bpf.c
  int _version __attribute__((section("version"), used)) = LINUX_VERSION_CODE;
  # perf record -e bpf.c sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.017 MB perf.data ]
  # perf evlist -v
  perf_bpf_probe:fork: type: 2, size: 112, config: 0x5ee, { sample_period,
  sample_freq }: 1, sample_type: IP|TID|TIME|CPU|PERIOD|RAW, disabled: 1,
  inherit: 1, mmap: 1, comm: 1, enable_on_exec: 1, task: 1, sample_id_all:
  1, exclude_guest: 1, mmap2: 1, comm_exec: 1
  #

Suggested-and-Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446636007-239722-3-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Wang Nan 2015-11-04 11:20:05 +00:00 committed by Arnaldo Carvalho de Melo
parent 59f41af980
commit 4a4f66a1a7
1 changed files with 27 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

27
tools/perf/util/llvm-utils.c
View file

@ -12,6 +12,7 @@
#define CLANG_BPF_CMD_DEFAULT_TEMPLATE \
"$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
"-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \
"$CLANG_OPTIONS $KERNEL_INC_OPTIONS " \
"-Wno-unused-value -Wno-pointer-sign " \
"-working-directory $WORKING_DIR " \
@ -324,11 +325,33 @@ get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
pr_debug("include option is set to %s\n", *kbuild_include_opts);
}
static unsigned long
fetch_kernel_version(void)
{
struct utsname utsname;
int version, patchlevel, sublevel, err;
if (uname(&utsname))
return 0;
err = sscanf(utsname.release, "%d.%d.%d",
&version, &patchlevel, &sublevel);
if (err != 3) {
pr_debug("Unablt to get kernel version from uname '%s'\n",
utsname.release);
return 0;
}
return (version << 16) + (patchlevel << 8) + sublevel;
}
int llvm__compile_bpf(const char *path, void **p_obj_buf,
size_t *p_obj_buf_sz)
{
int err, nr_cpus_avail;
char clang_path[PATH_MAX], nr_cpus_avail_str[64];
char linux_version_code_str[64];
const char *clang_opt = llvm_param.clang_opt;
const char *template = llvm_param.clang_bpf_cmd_template;
char *kbuild_dir = NULL, *kbuild_include_opts = NULL;
@ -365,7 +388,11 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf,
snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
nr_cpus_avail);
snprintf(linux_version_code_str, sizeof(linux_version_code_str),
"0x%lx", fetch_kernel_version());
force_set_env("NR_CPUS", nr_cpus_avail_str);
force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
force_set_env("CLANG_EXEC", clang_path);
force_set_env("CLANG_OPTIONS", clang_opt);
force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);