Em Wed, Sep 19, 2018 at 03:39:35PM -0700, Alexei Starovoitov escreveu:
> Recognize JITed bpf prog load/unload events.
> Add/remove kernel symbols accordingly.
>
> Signed-off-by: Alexei Starovoitov <a...@kernel.org>
> ---
> tools/perf/util/machine.c | 27 +++++++++++++++++++++++++++
> tools/perf/util/symbol.c | 13 +++++++++++++
> tools/perf/util/symbol.h | 1 +
> 3 files changed, 41 insertions(+)
>
> diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
> index c4acd2001db0..ae4f8a0fdc7e 100644
> --- a/tools/perf/util/machine.c
> +++ b/tools/perf/util/machine.c
> @@ -25,6 +25,7 @@
> #include "sane_ctype.h"
> #include <symbol/kallsyms.h>
> #include <linux/mman.h>
> +#include <linux/magic.h>
>
> static void __machine__remove_thread(struct machine *machine, struct thread
> *th, bool lock);
>
> @@ -1460,6 +1461,32 @@ static int machine__process_kernel_mmap_event(struct
> machine *machine,
> enum dso_kernel_type kernel_type;
> bool is_kernel_mmap;
>
> + /* process JITed bpf programs load/unload events */
> + if (event->mmap.pid == ~0u && event->mmap.tid == BPF_FS_MAGIC) {
So, this would be in machine__process_kernel_munmap-event(machine), etc,
no check for BPF_FS_MAGIC would be needed with a PERF_RECORD_MUNMAP.
> + struct symbol *sym;
> + u64 ip;
> +
> + map = map_groups__find(&machine->kmaps, event->mmap.start);
> + if (!map) {
> + pr_err("No kernel map for IP %lx\n", event->mmap.start);
> + goto out_problem;
> + }
> + ip = event->mmap.start - map->start + map->pgoff;
> + if (event->mmap.filename[0]) {
> + sym = symbol__new(ip, event->mmap.len, 0, 0,
> + event->mmap.filename);
Humm, so the bpf program would be just one symbol... bpf-to-bpf calls
will be to a different bpf program, right?
/me goes to read https://lwn.net/Articles/741773/
"[PATCH bpf-next 00/13] bpf: introduce function calls"
> + dso__insert_symbol(map->dso, sym);
> + } else {
> + if (symbols__erase(&map->dso->symbols, ip)) {
> + pr_err("No bpf prog at IP %lx/%lx\n",
> + event->mmap.start, ip);
> + goto out_problem;
> + }
> + dso__reset_find_symbol_cache(map->dso);
> + }
> + return 0;
> + }
> +
> /* If we have maps from kcore then we do not need or want any others */
> if (machine__uses_kcore(machine))
> return 0;
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index d188b7588152..0653f313661d 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -353,6 +353,19 @@ static struct symbol *symbols__find(struct rb_root
> *symbols, u64 ip)
> return NULL;
> }
>
> +int symbols__erase(struct rb_root *symbols, u64 ip)
> +{
> + struct symbol *s;
> +
> + s = symbols__find(symbols, ip);
> + if (!s)
> + return -ENOENT;
> +
> + rb_erase(&s->rb_node, symbols);
> + symbol__delete(s);
> + return 0;
> +}
> +
> static struct symbol *symbols__first(struct rb_root *symbols)
> {
> struct rb_node *n = rb_first(symbols);
> diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
> index f25fae4b5743..92ef31953d9a 100644
> --- a/tools/perf/util/symbol.h
> +++ b/tools/perf/util/symbol.h
> @@ -310,6 +310,7 @@ char *dso__demangle_sym(struct dso *dso, int kmodule,
> const char *elf_name);
>
> void __symbols__insert(struct rb_root *symbols, struct symbol *sym, bool
> kernel);
> void symbols__insert(struct rb_root *symbols, struct symbol *sym);
> +int symbols__erase(struct rb_root *symbols, u64 ip);
> void symbols__fixup_duplicate(struct rb_root *symbols);
> void symbols__fixup_end(struct rb_root *symbols);
> void map_groups__fixup_end(struct map_groups *mg);
> --
> 2.17.1
