Em Thu, Nov 05, 2020 at 09:25:49PM -0800, Andrii Nakryiko escreveu: > Add support for generating split BTF, in which there is a designated base > BTF, containing a base set of types, and a split BTF, which extends main BTF > with extra types, that can reference types and strings from the main BTF. > This is going to be used to generate compact BTFs for kernel modules, with > vmlinux BTF being a main BTF, which all kernel modules are based off of. > These changes rely on patch set [0] to be present in libbpf submodule. > [0] https://patchwork.kernel.org/project/netdevbpf/list/?series=377859&state=* So, applied and added this: diff --git a/man-pages/pahole.1 b/man-pages/pahole.1 index 4b5e0a1bf5462b28..20ee91fc911d4b39 100644 --- a/man-pages/pahole.1 +++ b/man-pages/pahole.1 @@ -185,6 +185,10 @@ Do not encode VARs in BTF. .B \-\-btf_encode_force Ignore those symbols found invalid when encoding BTF. +.TP +.B \-\-btf_base +Path to the base BTF file, for instance: vmlinux when encoding kernel module BTF information. + .TP .B \-l, \-\-show_first_biggest_size_base_type_member Show first biggest size base_type member. --------------- The entry for btf_encode/-J is missing, I'll add in a followup patch. Also I had to fixup ARGP_btf_base to 321 as I added this, to simplify the kernel scripts and Makefiles: $ pahole --numeric_version 118 $ Now to test this all by applying the kernel patches and the encoding module BTF, looking at it, etc. - Arnaldo > Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> > --- > btf_encoder.c | 3 ++- > btf_loader.c | 2 +- > libbtf.c | 10 ++++++---- > libbtf.h | 4 +++- > pahole.c | 23 +++++++++++++++++++++++ > 5 files changed, 35 insertions(+), 7 deletions(-) > > diff --git a/btf_encoder.c b/btf_encoder.c > index b3e47f172bb3..d67e29b9cbee 100644 > --- a/btf_encoder.c > +++ b/btf_encoder.c > @@ -12,6 +12,7 @@ > #include "dwarves.h" > #include "libbtf.h" > #include "lib/bpf/include/uapi/linux/btf.h" > +#include "lib/bpf/src/libbpf.h" > #include "hash.h" > #include "elf_symtab.h" > #include "btf_encoder.h" > @@ -343,7 +344,7 @@ int cu__encode_btf(struct cu *cu, int verbose, bool force, > } > > if (!btfe) { > - btfe = btf_elf__new(cu->filename, cu->elf); > + btfe = btf_elf__new(cu->filename, cu->elf, base_btf); > if (!btfe) > return -1; > > diff --git a/btf_loader.c b/btf_loader.c > index 6ea207ea65b4..ec286f413f36 100644 > --- a/btf_loader.c > +++ b/btf_loader.c > @@ -534,7 +534,7 @@ struct debug_fmt_ops btf_elf__ops; > int btf_elf__load_file(struct cus *cus, struct conf_load *conf, const char *filename) > { > int err; > - struct btf_elf *btfe = btf_elf__new(filename, NULL); > + struct btf_elf *btfe = btf_elf__new(filename, NULL, base_btf); > > if (btfe == NULL) > return -1; > diff --git a/libbtf.c b/libbtf.c > index b6ddd7599395..3c52aa0d482b 100644 > --- a/libbtf.c > +++ b/libbtf.c > @@ -27,6 +27,7 @@ > #include "dwarves.h" > #include "elf_symtab.h" > > +struct btf *base_btf; > uint8_t btf_elf__verbose; > uint8_t btf_elf__force; > > @@ -52,9 +53,9 @@ int btf_elf__load(struct btf_elf *btfe) > /* free initial empty BTF */ > btf__free(btfe->btf); > if (btfe->raw_btf) > - btfe->btf = btf__parse_raw(btfe->filename); > + btfe->btf = btf__parse_raw_split(btfe->filename, btfe->base_btf); > else > - btfe->btf = btf__parse_elf(btfe->filename, NULL); > + btfe->btf = btf__parse_elf_split(btfe->filename, btfe->base_btf); > > err = libbpf_get_error(btfe->btf); > if (err) > @@ -63,7 +64,7 @@ int btf_elf__load(struct btf_elf *btfe) > return 0; > } > > -struct btf_elf *btf_elf__new(const char *filename, Elf *elf) > +struct btf_elf *btf_elf__new(const char *filename, Elf *elf, struct btf *base_btf) > { > struct btf_elf *btfe = zalloc(sizeof(*btfe)); > GElf_Shdr shdr; > @@ -77,7 +78,8 @@ struct btf_elf *btf_elf__new(const char *filename, Elf *elf) > if (btfe->filename == NULL) > goto errout; > > - btfe->btf = btf__new_empty(); > + btfe->base_btf = base_btf; > + btfe->btf = btf__new_empty_split(base_btf); > if (libbpf_get_error(btfe->btf)) { > fprintf(stderr, "%s: failed to create empty BTF.\n", __func__); > goto errout; > diff --git a/libbtf.h b/libbtf.h > index 887b5bc55c8e..71f6cecbea93 100644 > --- a/libbtf.h > +++ b/libbtf.h > @@ -27,8 +27,10 @@ struct btf_elf { > uint32_t percpu_shndx; > uint64_t percpu_base_addr; > struct btf *btf; > + struct btf *base_btf; > }; > > +extern struct btf *base_btf; > extern uint8_t btf_elf__verbose; > extern uint8_t btf_elf__force; > #define btf_elf__verbose_log(fmt, ...) { if (btf_elf__verbose) printf(fmt, __VA_ARGS__); } > @@ -39,7 +41,7 @@ struct cu; > struct base_type; > struct ftype; > > -struct btf_elf *btf_elf__new(const char *filename, Elf *elf); > +struct btf_elf *btf_elf__new(const char *filename, Elf *elf, struct btf *base_btf); > void btf_elf__delete(struct btf_elf *btf); > > int32_t btf_elf__add_base_type(struct btf_elf *btf, const struct base_type *bt, > diff --git a/pahole.c b/pahole.c > index bd9b993777ee..d18092c1212c 100644 > --- a/pahole.c > +++ b/pahole.c > @@ -22,12 +22,15 @@ > #include "dutil.h" > #include "ctf_encoder.h" > #include "btf_encoder.h" > +#include "libbtf.h" > +#include "lib/bpf/src/libbpf.h" > > static bool btf_encode; > static bool ctf_encode; > static bool first_obj_only; > static bool skip_encoding_btf_vars; > static bool btf_encode_force; > +static const char *base_btf_file; > > static uint8_t class__include_anonymous; > static uint8_t class__include_nested_anonymous; > @@ -820,6 +823,7 @@ ARGP_PROGRAM_VERSION_HOOK_DEF = dwarves_print_version; > #define ARGP_skip_encoding_btf_vars 317 > #define ARGP_btf_encode_force 318 > #define ARGP_just_packed_structs 319 > +#define ARGP_btf_base 320 > > static const struct argp_option pahole__options[] = { > { > @@ -1093,6 +1097,12 @@ static const struct argp_option pahole__options[] = { > .key = ARGP_hex_fmt, > .doc = "Print offsets and sizes in hexadecimal", > }, > + { > + .name = "btf_base", > + .key = ARGP_btf_base, > + .arg = "SIZE", > + .doc = "Path to the base BTF file", > + }, > { > .name = "btf_encode", > .key = 'J', > @@ -1234,6 +1244,9 @@ static error_t pahole__options_parser(int key, char *arg, > skip_encoding_btf_vars = true; break; > case ARGP_btf_encode_force: > btf_encode_force = true; break; > + case ARGP_btf_base: > + base_btf_file = arg; > + break; > default: > return ARGP_ERR_UNKNOWN; > } > @@ -2682,6 +2695,15 @@ int main(int argc, char *argv[]) > goto out; > } > > + if (base_btf_file) { > + base_btf = btf__parse(base_btf_file, NULL); > + if (libbpf_get_error(base_btf)) { > + fprintf(stderr, "Failed to parse base BTF '%s': %ld\n", > + base_btf_file, libbpf_get_error(base_btf)); > + goto out; > + } > + } > + > struct cus *cus = cus__new(); > if (cus == NULL) { > fputs("pahole: insufficient memory\n", stderr); > @@ -2766,6 +2788,7 @@ out_cus_delete: > #ifdef DEBUG_CHECK_LEAKS > cus__delete(cus); > structures__delete(); > + btf__free(base_btf); > #endif > out_dwarves_exit: > #ifdef DEBUG_CHECK_LEAKS > -- > 2.24.1 > -- - Arnaldo
