Re: [PATCH 1/1] perf bpf: Move BPF disassembly routines to separate file to avoid clash with capstone bpf headers

From: Namhyung Kim
Date: Wed Jul 31 2024 - 13:08:13 EST

On Wed, Jul 31, 2024 at 8:12 AM Arnaldo Carvalho de Melo
<acme@xxxxxxxxxx> wrote:
>
> There is a clash of the libbpf and capstone libraries, that ends up
> with:
>
> In file included from /usr/include/capstone/capstone.h:325,
> from util/disasm.c:1513:
> /usr/include/capstone/bpf.h:94:14: error: ‘bpf_insn’ defined as wrong kind of tag
> 94 | typedef enum bpf_insn {
>
> So far we're just trying to avoid this by not having both headers
> included in the same .c or .h file, do it one more time by moving the
> BPF diassembly routines from util/disasm.c to util/disasm_bpf.c.
>
> This is only being hit when building with BUILD_NONDISTRO=1, i.e.
> building with binutils-devel, that isn't the in the default build due to
> a licencing clash. We need to reimplement what is now isolated in
> util/disasm_bpf.c using some other library to have BPF annotation
> feature that now only is available with BUILD_NONDISTRO=1.
>
> Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Cc: Ian Rogers <irogers@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Song Liu <song@xxxxxxxxxx>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> ---
> tools/perf/util/Build | 1 +
> tools/perf/util/disasm.c | 187 +--------------------------------
> tools/perf/util/disasm_bpf.c | 193 +++++++++++++++++++++++++++++++++++
> tools/perf/util/disasm_bpf.h | 12 +++
> 4 files changed, 207 insertions(+), 186 deletions(-)
> create mode 100644 tools/perf/util/disasm_bpf.c
> create mode 100644 tools/perf/util/disasm_bpf.h
>
> diff --git a/tools/perf/util/Build b/tools/perf/util/Build
> index 0f18fe81ef0b2a74..b24360c04aaea424 100644
> --- a/tools/perf/util/Build
> +++ b/tools/perf/util/Build
> @@ -13,6 +13,7 @@ perf-util-y += copyfile.o
> perf-util-y += ctype.o
> perf-util-y += db-export.o
> perf-util-y += disasm.o
> +perf-util-y += disasm_bpf.o

I think this can be gated by LIBBFD and LIBBPF config, but not sure
it can express the both requirements easily.

thanks,
Namhyung


> perf-util-y += env.o
> perf-util-y += event.o
> perf-util-y += evlist.o
> diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c
> index 410e52cd9cfd0306..85fb0cfedf94554b 100644
> --- a/tools/perf/util/disasm.c
> +++ b/tools/perf/util/disasm.c
> @@ -16,6 +16,7 @@
> #include "build-id.h"
> #include "debug.h"
> #include "disasm.h"
> +#include "disasm_bpf.h"
> #include "dso.h"
> #include "env.h"
> #include "evsel.h"
> @@ -1323,192 +1324,6 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
> return 0;
> }
>
> -#if defined(HAVE_LIBBFD_SUPPORT) && defined(HAVE_LIBBPF_SUPPORT)
> -#define PACKAGE "perf"
> -#include <bfd.h>
> -#include <dis-asm.h>
> -#include <bpf/bpf.h>
> -#include <bpf/btf.h>
> -#include <bpf/libbpf.h>
> -#include <linux/btf.h>
> -#include <tools/dis-asm-compat.h>
> -
> -#include "bpf-event.h"
> -#include "bpf-utils.h"
> -
> -static int symbol__disassemble_bpf(struct symbol *sym,
> - struct annotate_args *args)
> -{
> - struct annotation *notes = symbol__annotation(sym);
> - struct bpf_prog_linfo *prog_linfo = NULL;
> - struct bpf_prog_info_node *info_node;
> - int len = sym->end - sym->start;
> - disassembler_ftype disassemble;
> - struct map *map = args->ms.map;
> - struct perf_bpil *info_linear;
> - struct disassemble_info info;
> - struct dso *dso = map__dso(map);
> - int pc = 0, count, sub_id;
> - struct btf *btf = NULL;
> - char tpath[PATH_MAX];
> - size_t buf_size;
> - int nr_skip = 0;
> - char *buf;
> - bfd *bfdf;
> - int ret;
> - FILE *s;
> -
> - if (dso__binary_type(dso) != DSO_BINARY_TYPE__BPF_PROG_INFO)
> - return SYMBOL_ANNOTATE_ERRNO__BPF_INVALID_FILE;
> -
> - pr_debug("%s: handling sym %s addr %" PRIx64 " len %" PRIx64 "\n", __func__,
> - sym->name, sym->start, sym->end - sym->start);
> -
> - memset(tpath, 0, sizeof(tpath));
> - perf_exe(tpath, sizeof(tpath));
> -
> - bfdf = bfd_openr(tpath, NULL);
> - if (bfdf == NULL)
> - abort();
> -
> - if (!bfd_check_format(bfdf, bfd_object))
> - abort();
> -
> - s = open_memstream(&buf, &buf_size);
> - if (!s) {
> - ret = errno;
> - goto out;
> - }
> - init_disassemble_info_compat(&info, s,
> - (fprintf_ftype) fprintf,
> - fprintf_styled);
> - info.arch = bfd_get_arch(bfdf);
> - info.mach = bfd_get_mach(bfdf);
> -
> - info_node = perf_env__find_bpf_prog_info(dso__bpf_prog(dso)->env,
> - dso__bpf_prog(dso)->id);
> - if (!info_node) {
> - ret = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;
> - goto out;
> - }
> - info_linear = info_node->info_linear;
> - sub_id = dso__bpf_prog(dso)->sub_id;
> -
> - info.buffer = (void *)(uintptr_t)(info_linear->info.jited_prog_insns);
> - info.buffer_length = info_linear->info.jited_prog_len;
> -
> - if (info_linear->info.nr_line_info)
> - prog_linfo = bpf_prog_linfo__new(&info_linear->info);
> -
> - if (info_linear->info.btf_id) {
> - struct btf_node *node;
> -
> - node = perf_env__find_btf(dso__bpf_prog(dso)->env,
> - info_linear->info.btf_id);
> - if (node)
> - btf = btf__new((__u8 *)(node->data),
> - node->data_size);
> - }
> -
> - disassemble_init_for_target(&info);
> -
> -#ifdef DISASM_FOUR_ARGS_SIGNATURE
> - disassemble = disassembler(info.arch,
> - bfd_big_endian(bfdf),
> - info.mach,
> - bfdf);
> -#else
> - disassemble = disassembler(bfdf);
> -#endif
> - if (disassemble == NULL)
> - abort();
> -
> - fflush(s);
> - do {
> - const struct bpf_line_info *linfo = NULL;
> - struct disasm_line *dl;
> - size_t prev_buf_size;
> - const char *srcline;
> - u64 addr;
> -
> - addr = pc + ((u64 *)(uintptr_t)(info_linear->info.jited_ksyms))[sub_id];
> - count = disassemble(pc, &info);
> -
> - if (prog_linfo)
> - linfo = bpf_prog_linfo__lfind_addr_func(prog_linfo,
> - addr, sub_id,
> - nr_skip);
> -
> - if (linfo && btf) {
> - srcline = btf__name_by_offset(btf, linfo->line_off);
> - nr_skip++;
> - } else
> - srcline = NULL;
> -
> - fprintf(s, "\n");
> - prev_buf_size = buf_size;
> - fflush(s);
> -
> - if (!annotate_opts.hide_src_code && srcline) {
> - args->offset = -1;
> - args->line = strdup(srcline);
> - args->line_nr = 0;
> - args->fileloc = NULL;
> - args->ms.sym = sym;
> - dl = disasm_line__new(args);
> - if (dl) {
> - annotation_line__add(&dl->al,
> - &notes->src->source);
> - }
> - }
> -
> - args->offset = pc;
> - args->line = buf + prev_buf_size;
> - args->line_nr = 0;
> - args->fileloc = NULL;
> - args->ms.sym = sym;
> - dl = disasm_line__new(args);
> - if (dl)
> - annotation_line__add(&dl->al, &notes->src->source);
> -
> - pc += count;
> - } while (count > 0 && pc < len);
> -
> - ret = 0;
> -out:
> - free(prog_linfo);
> - btf__free(btf);
> - fclose(s);
> - bfd_close(bfdf);
> - return ret;
> -}
> -#else // defined(HAVE_LIBBFD_SUPPORT) && defined(HAVE_LIBBPF_SUPPORT)
> -static int symbol__disassemble_bpf(struct symbol *sym __maybe_unused,
> - struct annotate_args *args __maybe_unused)
> -{
> - return SYMBOL_ANNOTATE_ERRNO__NO_LIBOPCODES_FOR_BPF;
> -}
> -#endif // defined(HAVE_LIBBFD_SUPPORT) && defined(HAVE_LIBBPF_SUPPORT)
> -
> -static int
> -symbol__disassemble_bpf_image(struct symbol *sym,
> - struct annotate_args *args)
> -{
> - struct annotation *notes = symbol__annotation(sym);
> - struct disasm_line *dl;
> -
> - args->offset = -1;
> - args->line = strdup("to be implemented");
> - args->line_nr = 0;
> - args->fileloc = NULL;
> - dl = disasm_line__new(args);
> - if (dl)
> - annotation_line__add(&dl->al, &notes->src->source);
> -
> - zfree(&args->line);
> - return 0;
> -}
> -
> #ifdef HAVE_LIBCAPSTONE_SUPPORT
> #include <capstone/capstone.h>
>
> diff --git a/tools/perf/util/disasm_bpf.c b/tools/perf/util/disasm_bpf.c
> new file mode 100644
> index 0000000000000000..14994515beb341ce
> --- /dev/null
> +++ b/tools/perf/util/disasm_bpf.c
> @@ -0,0 +1,193 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +#include "util/annotate.h"
> +#include "util/disasm_bpf.h"
> +#include "util/symbol.h"
> +
> +#if defined(HAVE_LIBBFD_SUPPORT) && defined(HAVE_LIBBPF_SUPPORT)
> +#define PACKAGE "perf"
> +#include <bfd.h>
> +#include <bpf/bpf.h>
> +#include <bpf/btf.h>
> +#include <bpf/libbpf.h>
> +#include <dis-asm.h>
> +#include <errno.h>
> +#include <linux/btf.h>
> +#include <tools/dis-asm-compat.h>
> +
> +#include "util/bpf-event.h"
> +#include "util/bpf-utils.h"
> +#include "util/debug.h"
> +#include "util/dso.h"
> +#include "util/map.h"
> +#include "util/env.h"
> +#include "util/util.h"
> +
> +int symbol__disassemble_bpf(struct symbol *sym, struct annotate_args *args)
> +{
> + struct annotation *notes = symbol__annotation(sym);
> + struct bpf_prog_linfo *prog_linfo = NULL;
> + struct bpf_prog_info_node *info_node;
> + int len = sym->end - sym->start;
> + disassembler_ftype disassemble;
> + struct map *map = args->ms.map;
> + struct perf_bpil *info_linear;
> + struct disassemble_info info;
> + struct dso *dso = map__dso(map);
> + int pc = 0, count, sub_id;
> + struct btf *btf = NULL;
> + char tpath[PATH_MAX];
> + size_t buf_size;
> + int nr_skip = 0;
> + char *buf;
> + bfd *bfdf;
> + int ret;
> + FILE *s;
> +
> + if (dso__binary_type(dso) != DSO_BINARY_TYPE__BPF_PROG_INFO)
> + return SYMBOL_ANNOTATE_ERRNO__BPF_INVALID_FILE;
> +
> + pr_debug("%s: handling sym %s addr %" PRIx64 " len %" PRIx64 "\n", __func__,
> + sym->name, sym->start, sym->end - sym->start);
> +
> + memset(tpath, 0, sizeof(tpath));
> + perf_exe(tpath, sizeof(tpath));
> +
> + bfdf = bfd_openr(tpath, NULL);
> + if (bfdf == NULL)
> + abort();
> +
> + if (!bfd_check_format(bfdf, bfd_object))
> + abort();
> +
> + s = open_memstream(&buf, &buf_size);
> + if (!s) {
> + ret = errno;
> + goto out;
> + }
> + init_disassemble_info_compat(&info, s,
> + (fprintf_ftype) fprintf,
> + fprintf_styled);
> + info.arch = bfd_get_arch(bfdf);
> + info.mach = bfd_get_mach(bfdf);
> +
> + info_node = perf_env__find_bpf_prog_info(dso__bpf_prog(dso)->env,
> + dso__bpf_prog(dso)->id);
> + if (!info_node) {
> + ret = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;
> + goto out;
> + }
> + info_linear = info_node->info_linear;
> + sub_id = dso__bpf_prog(dso)->sub_id;
> +
> + info.buffer = (void *)(uintptr_t)(info_linear->info.jited_prog_insns);
> + info.buffer_length = info_linear->info.jited_prog_len;
> +
> + if (info_linear->info.nr_line_info)
> + prog_linfo = bpf_prog_linfo__new(&info_linear->info);
> +
> + if (info_linear->info.btf_id) {
> + struct btf_node *node;
> +
> + node = perf_env__find_btf(dso__bpf_prog(dso)->env,
> + info_linear->info.btf_id);
> + if (node)
> + btf = btf__new((__u8 *)(node->data),
> + node->data_size);
> + }
> +
> + disassemble_init_for_target(&info);
> +
> +#ifdef DISASM_FOUR_ARGS_SIGNATURE
> + disassemble = disassembler(info.arch,
> + bfd_big_endian(bfdf),
> + info.mach,
> + bfdf);
> +#else
> + disassemble = disassembler(bfdf);
> +#endif
> + if (disassemble == NULL)
> + abort();
> +
> + fflush(s);
> + do {
> + const struct bpf_line_info *linfo = NULL;
> + struct disasm_line *dl;
> + size_t prev_buf_size;
> + const char *srcline;
> + u64 addr;
> +
> + addr = pc + ((u64 *)(uintptr_t)(info_linear->info.jited_ksyms))[sub_id];
> + count = disassemble(pc, &info);
> +
> + if (prog_linfo)
> + linfo = bpf_prog_linfo__lfind_addr_func(prog_linfo,
> + addr, sub_id,
> + nr_skip);
> +
> + if (linfo && btf) {
> + srcline = btf__name_by_offset(btf, linfo->line_off);
> + nr_skip++;
> + } else
> + srcline = NULL;
> +
> + fprintf(s, "\n");
> + prev_buf_size = buf_size;
> + fflush(s);
> +
> + if (!annotate_opts.hide_src_code && srcline) {
> + args->offset = -1;
> + args->line = strdup(srcline);
> + args->line_nr = 0;
> + args->fileloc = NULL;
> + args->ms.sym = sym;
> + dl = disasm_line__new(args);
> + if (dl) {
> + annotation_line__add(&dl->al,
> + &notes->src->source);
> + }
> + }
> +
> + args->offset = pc;
> + args->line = buf + prev_buf_size;
> + args->line_nr = 0;
> + args->fileloc = NULL;
> + args->ms.sym = sym;
> + dl = disasm_line__new(args);
> + if (dl)
> + annotation_line__add(&dl->al, &notes->src->source);
> +
> + pc += count;
> + } while (count > 0 && pc < len);
> +
> + ret = 0;
> +out:
> + free(prog_linfo);
> + btf__free(btf);
> + fclose(s);
> + bfd_close(bfdf);
> + return ret;
> +}
> +#else // defined(HAVE_LIBBFD_SUPPORT) && defined(HAVE_LIBBPF_SUPPORT)
> +int symbol__disassemble_bpf(struct symbol *sym __maybe_unused, struct annotate_args *args __maybe_unused)
> +{
> + return SYMBOL_ANNOTATE_ERRNO__NO_LIBOPCODES_FOR_BPF;
> +}
> +#endif // defined(HAVE_LIBBFD_SUPPORT) && defined(HAVE_LIBBPF_SUPPORT)
> +
> +int symbol__disassemble_bpf_image(struct symbol *sym, struct annotate_args *args)
> +{
> + struct annotation *notes = symbol__annotation(sym);
> + struct disasm_line *dl;
> +
> + args->offset = -1;
> + args->line = strdup("to be implemented");
> + args->line_nr = 0;
> + args->fileloc = NULL;
> + dl = disasm_line__new(args);
> + if (dl)
> + annotation_line__add(&dl->al, &notes->src->source);
> +
> + zfree(&args->line);
> + return 0;
> +}
> diff --git a/tools/perf/util/disasm_bpf.h b/tools/perf/util/disasm_bpf.h
> new file mode 100644
> index 0000000000000000..2ecb19545388b114
> --- /dev/null
> +++ b/tools/perf/util/disasm_bpf.h
> @@ -0,0 +1,12 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +#ifndef __PERF_DISASM_BPF_H
> +#define __PERF_DISASM_BPF_H
> +
> +struct symbol;
> +struct annotate_args;
> +
> +int symbol__disassemble_bpf(struct symbol *sym, struct annotate_args *args);
> +int symbol__disassemble_bpf_image(struct symbol *sym, struct annotate_args *args);
> +
> +#endif /* __PERF_DISASM_BPF_H */
> --
> 2.45.2
>