From 5fbde62ba4cdd7b3e7b502b2c7fd5e776ca9d8ae Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Thu, 12 Mar 2020 20:55:59 +0100 Subject: [PATCH] UPSTREAM: bpf: Add name to struct bpf_ksym Adding name to 'struct bpf_ksym' object to carry the name of the symbol for bpf_prog, bpf_trampoline, bpf_dispatcher objects. The current benefit is that name is now generated only when the symbol is added to the list, so we don't need to generate it every time it's accessed. The future benefit is that we will have all the bpf objects symbols represented by struct bpf_ksym. Change-Id: Iff3d308e4f3b8464481655e297cc604c5f629b39 Signed-off-by: Jiri Olsa Signed-off-by: Alexei Starovoitov Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20200312195610.346362-5-jolsa@kernel.org Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 2 ++ include/linux/filter.h | 6 ------ kernel/bpf/core.c | 9 ++++++--- kernel/events/core.c | 9 ++++----- 4 files changed, 12 insertions(+), 14 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 24f78abfc1eb..32195c5dc5cc 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -18,6 +18,7 @@ #include #include #include +#include struct bpf_verifier_env; struct bpf_verifier_log; @@ -474,6 +475,7 @@ void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start); struct bpf_ksym { unsigned long start; unsigned long end; + char name[KSYM_NAME_LEN]; }; enum bpf_tramp_prog_type { diff --git a/include/linux/filter.h b/include/linux/filter.h index 6a25e23b2b13..fd24e04d379a 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -1164,7 +1164,6 @@ bpf_address_lookup(unsigned long addr, unsigned long *size, void bpf_prog_kallsyms_add(struct bpf_prog *fp); void bpf_prog_kallsyms_del(struct bpf_prog *fp); -void bpf_get_prog_name(const struct bpf_prog *prog, char *sym); #else /* CONFIG_BPF_JIT */ @@ -1228,11 +1227,6 @@ static inline void bpf_prog_kallsyms_del(struct bpf_prog *fp) { } -static inline void bpf_get_prog_name(const struct bpf_prog *prog, char *sym) -{ - sym[0] = '\0'; -} - #endif /* CONFIG_BPF_JIT */ void bpf_prog_kallsyms_del_all(struct bpf_prog *fp); diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 3136947294d3..0a3a53907670 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -545,8 +545,10 @@ bpf_prog_ksym_set_addr(struct bpf_prog *prog) prog->aux->ksym.end = addr + hdr->pages * PAGE_SIZE; } -void bpf_get_prog_name(const struct bpf_prog *prog, char *sym) +static void +bpf_prog_ksym_set_name(struct bpf_prog *prog) { + char *sym = prog->aux->ksym.name; const char *end = sym + KSYM_NAME_LEN; const struct btf_type *type; const char *func_name; @@ -653,6 +655,7 @@ void bpf_prog_kallsyms_add(struct bpf_prog *fp) return; bpf_prog_ksym_set_addr(fp); + bpf_prog_ksym_set_name(fp); spin_lock_bh(&bpf_lock); bpf_prog_ksym_node_add(fp->aux); @@ -691,7 +694,7 @@ const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, unsigned long symbol_start = prog->aux->ksym.start; unsigned long symbol_end = prog->aux->ksym.end; - bpf_get_prog_name(prog, sym); + strncpy(sym, prog->aux->ksym.name, KSYM_NAME_LEN); ret = sym; if (size) @@ -748,7 +751,7 @@ int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, if (it++ != symnum) continue; - bpf_get_prog_name(aux->prog, sym); + strncpy(sym, aux->ksym.name, KSYM_NAME_LEN); *value = (unsigned long)aux->prog->bpf_func; *type = BPF_SYM_ELF_TYPE; diff --git a/kernel/events/core.c b/kernel/events/core.c index 061d933805e3..1693ae71f6ee 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8229,23 +8229,22 @@ static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog, enum perf_bpf_event_type type) { bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD; - char sym[KSYM_NAME_LEN]; int i; if (prog->aux->func_cnt == 0) { - bpf_get_prog_name(prog, sym); perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, (u64)(unsigned long)prog->bpf_func, - prog->jited_len, unregister, sym); + prog->jited_len, unregister, + prog->aux->ksym.name); } else { for (i = 0; i < prog->aux->func_cnt; i++) { struct bpf_prog *subprog = prog->aux->func[i]; - bpf_get_prog_name(subprog, sym); perf_event_ksymbol( PERF_RECORD_KSYMBOL_TYPE_BPF, (u64)(unsigned long)subprog->bpf_func, - subprog->jited_len, unregister, sym); + subprog->jited_len, unregister, + prog->aux->ksym.name); } } }