diff options
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 15 | ||||
| -rw-r--r-- | include/linux/bpf.h | 6 | ||||
| -rw-r--r-- | include/linux/filter.h | 1 | ||||
| -rw-r--r-- | kernel/bpf/core.c | 8 | ||||
| -rw-r--r-- | kernel/bpf/trampoline.c | 23 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/fexit_stress.c | 4 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/trampoline_count.c | 4 |
7 files changed, 50 insertions, 11 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index d11b9bcebbea..79e7a0ec1da5 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1740,8 +1740,11 @@ static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog, struct bpf_prog *p, int stack_size, bool mod_ret) { u8 *prog = *pprog; + u8 *jmp_insn; int cnt = 0; + /* arg1: mov rdi, progs[i] */ + emit_mov_imm64(&prog, BPF_REG_1, (long) p >> 32, (u32) (long) p); if (emit_call(&prog, p->aux->sleepable ? __bpf_prog_enter_sleepable : __bpf_prog_enter, prog)) @@ -1749,6 +1752,14 @@ static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog, /* remember prog start time returned by __bpf_prog_enter */ emit_mov_reg(&prog, true, BPF_REG_6, BPF_REG_0); + /* if (__bpf_prog_enter*(prog) == 0) + * goto skip_exec_of_prog; + */ + EMIT3(0x48, 0x85, 0xC0); /* test rax,rax */ + /* emit 2 nops that will be replaced with JE insn */ + jmp_insn = prog; + emit_nops(&prog, 2); + /* arg1: lea rdi, [rbp - stack_size] */ EMIT4(0x48, 0x8D, 0x7D, -stack_size); /* arg2: progs[i]->insnsi for interpreter */ @@ -1767,6 +1778,10 @@ static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog, if (mod_ret) emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -8); + /* replace 2 nops with JE insn, since jmp target is known */ + jmp_insn[0] = X86_JE; + jmp_insn[1] = prog - jmp_insn - 2; + /* arg1: mov rdi, progs[i] */ emit_mov_imm64(&prog, BPF_REG_1, (long) p >> 32, (u32) (long) p); /* arg2: mov rsi, rbx <- start time in nsec */ diff --git a/include/linux/bpf.h b/include/linux/bpf.h index e1840ceaf55f..1c8ea682c007 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -529,7 +529,7 @@ struct btf_func_model { /* Each call __bpf_prog_enter + call bpf_func + call __bpf_prog_exit is ~50 * bytes on x86. Pick a number to fit into BPF_IMAGE_SIZE / 2 */ -#define BPF_MAX_TRAMP_PROGS 40 +#define BPF_MAX_TRAMP_PROGS 38 struct bpf_tramp_progs { struct bpf_prog *progs[BPF_MAX_TRAMP_PROGS]; @@ -561,9 +561,9 @@ int arch_prepare_bpf_trampoline(void *image, void *image_end, struct bpf_tramp_progs *tprogs, void *orig_call); /* these two functions are called from generated trampoline */ -u64 notrace __bpf_prog_enter(void); +u64 notrace __bpf_prog_enter(struct bpf_prog *prog); void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start); -u64 notrace __bpf_prog_enter_sleepable(void); +u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog); void notrace __bpf_prog_exit_sleepable(struct bpf_prog *prog, u64 start); struct bpf_ksym { diff --git a/include/linux/filter.h b/include/linux/filter.h index cecb03c9d251..6a06f3c69f4e 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -565,6 +565,7 @@ struct bpf_prog { u32 jited_len; /* Size of jited insns in bytes */ u8 tag[BPF_TAG_SIZE]; struct bpf_prog_stats __percpu *stats; + int __percpu *active; unsigned int (*bpf_func)(const void *ctx, const struct bpf_insn *insn); struct bpf_prog_aux *aux; /* Auxiliary fields */ diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 2cf71fd39c22..334070c4b8a1 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -91,6 +91,12 @@ struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flag vfree(fp); return NULL; } + fp->active = alloc_percpu_gfp(int, GFP_KERNEL_ACCOUNT | gfp_extra_flags); + if (!fp->active) { + vfree(fp); + kfree(aux); + return NULL; + } fp->pages = size / PAGE_SIZE; fp->aux = aux; @@ -116,6 +122,7 @@ struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags); if (!prog->stats) { + free_percpu(prog->active); kfree(prog->aux); vfree(prog); return NULL; @@ -253,6 +260,7 @@ void __bpf_prog_free(struct bpf_prog *fp) kfree(fp->aux); } free_percpu(fp->stats); + free_percpu(fp->active); vfree(fp); } diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 48eb021e1421..89ef6320d19b 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -381,13 +381,16 @@ out: mutex_unlock(&trampoline_mutex); } -#define NO_START_TIME 0 +#define NO_START_TIME 1 static u64 notrace bpf_prog_start_time(void) { u64 start = NO_START_TIME; - if (static_branch_unlikely(&bpf_stats_enabled_key)) + if (static_branch_unlikely(&bpf_stats_enabled_key)) { start = sched_clock(); + if (unlikely(!start)) + start = NO_START_TIME; + } return start; } @@ -397,12 +400,20 @@ static u64 notrace bpf_prog_start_time(void) * call __bpf_prog_enter * call prog->bpf_func * call __bpf_prog_exit + * + * __bpf_prog_enter returns: + * 0 - skip execution of the bpf prog + * 1 - execute bpf prog + * [2..MAX_U64] - excute bpf prog and record execution time. + * This is start time. */ -u64 notrace __bpf_prog_enter(void) +u64 notrace __bpf_prog_enter(struct bpf_prog *prog) __acquires(RCU) { rcu_read_lock(); migrate_disable(); + if (unlikely(__this_cpu_inc_return(*(prog->active)) != 1)) + return 0; return bpf_prog_start_time(); } @@ -430,21 +441,25 @@ void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start) __releases(RCU) { update_prog_stats(prog, start); + __this_cpu_dec(*(prog->active)); migrate_enable(); rcu_read_unlock(); } -u64 notrace __bpf_prog_enter_sleepable(void) +u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog) { rcu_read_lock_trace(); migrate_disable(); might_fault(); + if (unlikely(__this_cpu_inc_return(*(prog->active)) != 1)) + return 0; return bpf_prog_start_time(); } void notrace __bpf_prog_exit_sleepable(struct bpf_prog *prog, u64 start) { update_prog_stats(prog, start); + __this_cpu_dec(*(prog->active)); migrate_enable(); rcu_read_unlock_trace(); } diff --git a/tools/testing/selftests/bpf/prog_tests/fexit_stress.c b/tools/testing/selftests/bpf/prog_tests/fexit_stress.c index 3b9dbf7433f0..7c9b62e971f1 100644 --- a/tools/testing/selftests/bpf/prog_tests/fexit_stress.c +++ b/tools/testing/selftests/bpf/prog_tests/fexit_stress.c @@ -2,8 +2,8 @@ /* Copyright (c) 2019 Facebook */ #include <test_progs.h> -/* x86-64 fits 55 JITed and 43 interpreted progs into half page */ -#define CNT 40 +/* that's kernel internal BPF_MAX_TRAMP_PROGS define */ +#define CNT 38 void test_fexit_stress(void) { diff --git a/tools/testing/selftests/bpf/prog_tests/trampoline_count.c b/tools/testing/selftests/bpf/prog_tests/trampoline_count.c index 781c8d11604b..f3022d934e2d 100644 --- a/tools/testing/selftests/bpf/prog_tests/trampoline_count.c +++ b/tools/testing/selftests/bpf/prog_tests/trampoline_count.c @@ -4,7 +4,7 @@ #include <sys/prctl.h> #include <test_progs.h> -#define MAX_TRAMP_PROGS 40 +#define MAX_TRAMP_PROGS 38 struct inst { struct bpf_object *obj; @@ -52,7 +52,7 @@ void test_trampoline_count(void) struct bpf_link *link; char comm[16] = {}; - /* attach 'allowed' 40 trampoline programs */ + /* attach 'allowed' trampoline programs */ for (i = 0; i < MAX_TRAMP_PROGS; i++) { obj = bpf_object__open_file(object, NULL); if (CHECK(IS_ERR(obj), "obj_open_file", "err %ld\n", PTR_ERR(obj))) { |