diff options
author | Daniel Borkmann <daniel@iogearbox.net> | 2018-05-24 09:20:50 +0200 |
---|---|---|
committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-05-24 09:20:51 +0200 |
commit | 30cfe3b4d0a0bb389d173cdcad66f9f558c021be (patch) | |
tree | 368c31f0f2cd07cab7ff8abd445b8dc84aa761ec | |
parent | a2889a4c2d3aefdf6f2a636fa1531243653a7633 (diff) | |
parent | f7f62c7134288a704f90b137097e1ee689ff25ab (diff) |
Merge branch 'bpf-multi-prog-improvements'
Sandipan Das says:
====================
[1] Support for bpf-to-bpf function calls in the powerpc64 JIT compiler.
[2] Provide a way for resolving function calls because of the way JITed
images are allocated in powerpc64.
[3] Fix to get JITed instruction dumps for multi-function programs from
the bpf system call.
[4] Fix for bpftool to show delimited multi-function JITed image dumps.
v4:
- Incorporate review comments from Jakub.
- Fix JSON output for bpftool.
v3:
- Change base tree tag to bpf-next.
- Incorporate review comments from Alexei, Daniel and Jakub.
- Make sure that the JITed image does not grow or shrink after
the last pass due to the way the instruction sequence used
to load a callee's address maybe optimized.
- Make additional changes to the bpf system call and bpftool to
make multi-function JITed dumps easier to correlate.
v2:
- Incorporate review comments from Jakub.
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
-rw-r--r-- | arch/powerpc/net/bpf_jit_comp64.c | 110 | ||||
-rw-r--r-- | include/uapi/linux/bpf.h | 4 | ||||
-rw-r--r-- | kernel/bpf/syscall.c | 82 | ||||
-rw-r--r-- | kernel/bpf/verifier.c | 22 | ||||
-rw-r--r-- | tools/bpf/bpftool/prog.c | 97 | ||||
-rw-r--r-- | tools/bpf/bpftool/xlated_dumper.c | 14 | ||||
-rw-r--r-- | tools/bpf/bpftool/xlated_dumper.h | 3 | ||||
-rw-r--r-- | tools/include/uapi/linux/bpf.h | 4 |
8 files changed, 301 insertions, 35 deletions
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c index 1bdb1aff0619..f1c95779843b 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -167,25 +167,37 @@ static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx) static void bpf_jit_emit_func_call(u32 *image, struct codegen_context *ctx, u64 func) { + unsigned int i, ctx_idx = ctx->idx; + + /* Load function address into r12 */ + PPC_LI64(12, func); + + /* For bpf-to-bpf function calls, the callee's address is unknown + * until the last extra pass. As seen above, we use PPC_LI64() to + * load the callee's address, but this may optimize the number of + * instructions required based on the nature of the address. + * + * Since we don't want the number of instructions emitted to change, + * we pad the optimized PPC_LI64() call with NOPs to guarantee that + * we always have a five-instruction sequence, which is the maximum + * that PPC_LI64() can emit. + */ + for (i = ctx->idx - ctx_idx; i < 5; i++) + PPC_NOP(); + #ifdef PPC64_ELF_ABI_v1 - /* func points to the function descriptor */ - PPC_LI64(b2p[TMP_REG_2], func); - /* Load actual entry point from function descriptor */ - PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_2], 0); - /* ... and move it to LR */ - PPC_MTLR(b2p[TMP_REG_1]); /* * Load TOC from function descriptor at offset 8. * We can clobber r2 since we get called through a * function pointer (so caller will save/restore r2) * and since we don't use a TOC ourself. */ - PPC_BPF_LL(2, b2p[TMP_REG_2], 8); -#else - /* We can clobber r12 */ - PPC_FUNC_ADDR(12, func); - PPC_MTLR(12); + PPC_BPF_LL(2, 12, 8); + /* Load actual entry point from function descriptor */ + PPC_BPF_LL(12, 12, 0); #endif + + PPC_MTLR(12); PPC_BLRL(); } @@ -256,7 +268,7 @@ static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 /* Assemble the body code between the prologue & epilogue */ static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *ctx, - u32 *addrs) + u32 *addrs, bool extra_pass) { const struct bpf_insn *insn = fp->insnsi; int flen = fp->len; @@ -712,11 +724,25 @@ emit_clear: break; /* - * Call kernel helper + * Call kernel helper or bpf function */ case BPF_JMP | BPF_CALL: ctx->seen |= SEEN_FUNC; - func = (u8 *) __bpf_call_base + imm; + + /* bpf function call */ + if (insn[i].src_reg == BPF_PSEUDO_CALL) + if (!extra_pass) + func = NULL; + else if (fp->aux->func && off < fp->aux->func_cnt) + /* use the subprog id from the off + * field to lookup the callee address + */ + func = (u8 *) fp->aux->func[off]->bpf_func; + else + return -EINVAL; + /* kernel helper call */ + else + func = (u8 *) __bpf_call_base + imm; bpf_jit_emit_func_call(image, ctx, (u64)func); @@ -864,6 +890,14 @@ cond_branch: return 0; } +struct powerpc64_jit_data { + struct bpf_binary_header *header; + u32 *addrs; + u8 *image; + u32 proglen; + struct codegen_context ctx; +}; + struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) { u32 proglen; @@ -871,6 +905,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) u8 *image = NULL; u32 *code_base; u32 *addrs; + struct powerpc64_jit_data *jit_data; struct codegen_context cgctx; int pass; int flen; @@ -878,6 +913,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) struct bpf_prog *org_fp = fp; struct bpf_prog *tmp_fp; bool bpf_blinded = false; + bool extra_pass = false; if (!fp->jit_requested) return org_fp; @@ -891,11 +927,32 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) fp = tmp_fp; } + jit_data = fp->aux->jit_data; + if (!jit_data) { + jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL); + if (!jit_data) { + fp = org_fp; + goto out; + } + fp->aux->jit_data = jit_data; + } + flen = fp->len; + addrs = jit_data->addrs; + if (addrs) { + cgctx = jit_data->ctx; + image = jit_data->image; + bpf_hdr = jit_data->header; + proglen = jit_data->proglen; + alloclen = proglen + FUNCTION_DESCR_SIZE; + extra_pass = true; + goto skip_init_ctx; + } + addrs = kzalloc((flen+1) * sizeof(*addrs), GFP_KERNEL); if (addrs == NULL) { fp = org_fp; - goto out; + goto out_addrs; } memset(&cgctx, 0, sizeof(struct codegen_context)); @@ -904,10 +961,10 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) cgctx.stack_size = round_up(fp->aux->stack_depth, 16); /* Scouting faux-generate pass 0 */ - if (bpf_jit_build_body(fp, 0, &cgctx, addrs)) { + if (bpf_jit_build_body(fp, 0, &cgctx, addrs, false)) { /* We hit something illegal or unsupported. */ fp = org_fp; - goto out; + goto out_addrs; } /* @@ -925,9 +982,10 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) bpf_jit_fill_ill_insns); if (!bpf_hdr) { fp = org_fp; - goto out; + goto out_addrs; } +skip_init_ctx: code_base = (u32 *)(image + FUNCTION_DESCR_SIZE); /* Code generation passes 1-2 */ @@ -935,7 +993,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) /* Now build the prologue, body code & epilogue for real. */ cgctx.idx = 0; bpf_jit_build_prologue(code_base, &cgctx); - bpf_jit_build_body(fp, code_base, &cgctx, addrs); + bpf_jit_build_body(fp, code_base, &cgctx, addrs, extra_pass); bpf_jit_build_epilogue(code_base, &cgctx); if (bpf_jit_enable > 1) @@ -961,10 +1019,20 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) fp->jited_len = alloclen; bpf_flush_icache(bpf_hdr, (u8 *)bpf_hdr + (bpf_hdr->pages * PAGE_SIZE)); + if (!fp->is_func || extra_pass) { +out_addrs: + kfree(addrs); + kfree(jit_data); + fp->aux->jit_data = NULL; + } else { + jit_data->addrs = addrs; + jit_data->ctx = cgctx; + jit_data->proglen = proglen; + jit_data->image = image; + jit_data->header = bpf_hdr; + } out: - kfree(addrs); - if (bpf_blinded) bpf_jit_prog_release_other(fp, fp == org_fp ? tmp_fp : org_fp); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index c3e502d06bc3..344d2ddcef49 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2205,6 +2205,10 @@ struct bpf_prog_info { __u32 gpl_compatible:1; __u64 netns_dev; __u64 netns_ino; + __u32 nr_jited_ksyms; + __u32 nr_jited_func_lens; + __aligned_u64 jited_ksyms; + __aligned_u64 jited_func_lens; } __attribute__((aligned(8))); struct bpf_map_info { diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 0b4c94551001..788456c18617 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1933,6 +1933,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, if (!capable(CAP_SYS_ADMIN)) { info.jited_prog_len = 0; info.xlated_prog_len = 0; + info.nr_jited_ksyms = 0; goto done; } @@ -1969,18 +1970,93 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, * for offload. */ ulen = info.jited_prog_len; - info.jited_prog_len = prog->jited_len; + if (prog->aux->func_cnt) { + u32 i; + + info.jited_prog_len = 0; + for (i = 0; i < prog->aux->func_cnt; i++) + info.jited_prog_len += prog->aux->func[i]->jited_len; + } else { + info.jited_prog_len = prog->jited_len; + } + if (info.jited_prog_len && ulen) { if (bpf_dump_raw_ok()) { uinsns = u64_to_user_ptr(info.jited_prog_insns); ulen = min_t(u32, info.jited_prog_len, ulen); - if (copy_to_user(uinsns, prog->bpf_func, ulen)) - return -EFAULT; + + /* for multi-function programs, copy the JITed + * instructions for all the functions + */ + if (prog->aux->func_cnt) { + u32 len, free, i; + u8 *img; + + free = ulen; + for (i = 0; i < prog->aux->func_cnt; i++) { + len = prog->aux->func[i]->jited_len; + len = min_t(u32, len, free); + img = (u8 *) prog->aux->func[i]->bpf_func; + if (copy_to_user(uinsns, img, len)) + return -EFAULT; + uinsns += len; + free -= len; + if (!free) + break; + } + } else { + if (copy_to_user(uinsns, prog->bpf_func, ulen)) + return -EFAULT; + } } else { info.jited_prog_insns = 0; } } + ulen = info.nr_jited_ksyms; + info.nr_jited_ksyms = prog->aux->func_cnt; + if (info.nr_jited_ksyms && ulen) { + if (bpf_dump_raw_ok()) { + u64 __user *user_ksyms; + ulong ksym_addr; + u32 i; + + /* copy the address of the kernel symbol + * corresponding to each function + */ + ulen = min_t(u32, info.nr_jited_ksyms, ulen); + user_ksyms = u64_to_user_ptr(info.jited_ksyms); + for (i = 0; i < ulen; i++) { + ksym_addr = (ulong) prog->aux->func[i]->bpf_func; + ksym_addr &= PAGE_MASK; + if (put_user((u64) ksym_addr, &user_ksyms[i])) + return -EFAULT; + } + } else { + info.jited_ksyms = 0; + } + } + + ulen = info.nr_jited_func_lens; + info.nr_jited_func_lens = prog->aux->func_cnt; + if (info.nr_jited_func_lens && ulen) { + if (bpf_dump_raw_ok()) { + u32 __user *user_lens; + u32 func_len, i; + + /* copy the JITed image lengths for each function */ + ulen = min_t(u32, info.nr_jited_func_lens, ulen); + user_lens = u64_to_user_ptr(info.jited_func_lens); + for (i = 0; i < ulen; i++) { + func_len = prog->aux->func[i]->jited_len; + if (put_user(func_len, &user_lens[i])) + return -EFAULT; + } + } else { + info.jited_func_lens = 0; + } + } + done: if (copy_to_user(uinfo, &info, info_len) || put_user(info_len, &uattr->info.info_len)) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a9e4b1372da6..8c4d9d0fd3ab 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5383,11 +5383,24 @@ static int jit_subprogs(struct bpf_verifier_env *env) insn->src_reg != BPF_PSEUDO_CALL) continue; subprog = insn->off; - insn->off = 0; insn->imm = (u64 (*)(u64, u64, u64, u64, u64)) func[subprog]->bpf_func - __bpf_call_base; } + + /* we use the aux data to keep a list of the start addresses + * of the JITed images for each function in the program + * + * for some architectures, such as powerpc64, the imm field + * might not be large enough to hold the offset of the start + * address of the callee's JITed image from __bpf_call_base + * + * in such cases, we can lookup the start address of a callee + * by using its subprog id, available from the off field of + * the call instruction, as an index for this list + */ + func[i]->aux->func = func; + func[i]->aux->func_cnt = env->subprog_cnt; } for (i = 0; i < env->subprog_cnt; i++) { old_bpf_func = func[i]->bpf_func; @@ -5413,17 +5426,12 @@ static int jit_subprogs(struct bpf_verifier_env *env) * later look the same as if they were interpreted only. */ for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { - unsigned long addr; - if (insn->code != (BPF_JMP | BPF_CALL) || insn->src_reg != BPF_PSEUDO_CALL) continue; insn->off = env->insn_aux_data[i].call_imm; subprog = find_subprog(env, i + insn->off + 1); - addr = (unsigned long)func[subprog]->bpf_func; - addr &= PAGE_MASK; - insn->imm = (u64 (*)(u64, u64, u64, u64, u64)) - addr - __bpf_call_base; + insn->imm = subprog; } prog->jited = 1; diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c index 9bdfdf2d3fbe..39b88e760367 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -420,7 +420,11 @@ static int do_show(int argc, char **argv) static int do_dump(int argc, char **argv) { + unsigned long *func_ksyms = NULL; struct bpf_prog_info info = {}; + unsigned int *func_lens = NULL; + unsigned int nr_func_ksyms; + unsigned int nr_func_lens; struct dump_data dd = {}; __u32 len = sizeof(info); unsigned int buf_size; @@ -496,10 +500,34 @@ static int do_dump(int argc, char **argv) return -1; } + nr_func_ksyms = info.nr_jited_ksyms; + if (nr_func_ksyms) { + func_ksyms = malloc(nr_func_ksyms * sizeof(__u64)); + if (!func_ksyms) { + p_err("mem alloc failed"); + close(fd); + goto err_free; + } + } + + nr_func_lens = info.nr_jited_func_lens; + if (nr_func_lens) { + func_lens = malloc(nr_func_lens * sizeof(__u32)); + if (!func_lens) { + p_err("mem alloc failed"); + close(fd); + goto err_free; + } + } + memset(&info, 0, sizeof(info)); *member_ptr = ptr_to_u64(buf); *member_len = buf_size; + info.jited_ksyms = ptr_to_u64(func_ksyms); + info.nr_jited_ksyms = nr_func_ksyms; + info.jited_func_lens = ptr_to_u64(func_lens); + info.nr_jited_func_lens = nr_func_lens; err = bpf_obj_get_info_by_fd(fd, &info, &len); close(fd); @@ -513,6 +541,16 @@ static int do_dump(int argc, char **argv) goto err_free; } + if (info.nr_jited_ksyms > nr_func_ksyms) { + p_err("too many addresses returned"); + goto err_free; + } + + if (info.nr_jited_func_lens > nr_func_lens) { + p_err("too many values returned"); + goto err_free; + } + if ((member_len == &info.jited_prog_len && info.jited_prog_insns == 0) || (member_len == &info.xlated_prog_len && @@ -550,7 +588,57 @@ static int do_dump(int argc, char **argv) goto err_free; } - disasm_print_insn(buf, *member_len, opcodes, name); + if (info.nr_jited_func_lens && info.jited_func_lens) { + struct kernel_sym *sym = NULL; + char sym_name[SYM_MAX_NAME]; + unsigned char *img = buf; + __u64 *ksyms = NULL; + __u32 *lens; + __u32 i; + + if (info.nr_jited_ksyms) { + kernel_syms_load(&dd); + ksyms = (__u64 *) info.jited_ksyms; + } + + if (json_output) + jsonw_start_array(json_wtr); + + lens = (__u32 *) info.jited_func_lens; + for (i = 0; i < info.nr_jited_func_lens; i++) { + if (ksyms) { + sym = kernel_syms_search(&dd, ksyms[i]); + if (sym) + sprintf(sym_name, "%s", sym->name); + else + sprintf(sym_name, "0x%016llx", ksyms[i]); + } else { + strcpy(sym_name, "unknown"); + } + + if (json_output) { + jsonw_start_object(json_wtr); + jsonw_name(json_wtr, "name"); + jsonw_string(json_wtr, sym_name); + jsonw_name(json_wtr, "insns"); + } else { + printf("%s:\n", sym_name); + } + + disasm_print_insn(img, lens[i], opcodes, name); + img += lens[i]; + + if (json_output) + jsonw_end_object(json_wtr); + else + printf("\n"); + } + + if (json_output) + jsonw_end_array(json_wtr); + } else { + disasm_print_insn(buf, *member_len, opcodes, name); + } } else if (visual) { if (json_output) jsonw_null(json_wtr); @@ -558,6 +646,9 @@ static int do_dump(int argc, char **argv) dump_xlated_cfg(buf, *member_len); } else { kernel_syms_load(&dd); + dd.nr_jited_ksyms = info.nr_jited_ksyms; + dd.jited_ksyms = (__u64 *) info.jited_ksyms; + if (json_output) dump_xlated_json(&dd, buf, *member_len, opcodes); else @@ -566,10 +657,14 @@ static int do_dump(int argc, char **argv) } free(buf); + free(func_ksyms); + free(func_lens); return 0; err_free: free(buf); + free(func_ksyms); + free(func_lens); return -1; } diff --git a/tools/bpf/bpftool/xlated_dumper.c b/tools/bpf/bpftool/xlated_dumper.c index 7a3173b76c16..b97f1da60dd1 100644 --- a/tools/bpf/bpftool/xlated_dumper.c +++ b/tools/bpf/bpftool/xlated_dumper.c @@ -102,8 +102,8 @@ void kernel_syms_destroy(struct dump_data *dd) free(dd->sym_mapping); } -static struct kernel_sym *kernel_syms_search(struct dump_data *dd, - unsigned long key) +struct kernel_sym *kernel_syms_search(struct dump_data *dd, + unsigned long key) { struct kernel_sym sym = { .address = key, @@ -174,7 +174,11 @@ static const char *print_call_pcrel(struct dump_data *dd, unsigned long address, const struct bpf_insn *insn) { - if (sym) + if (!dd->nr_jited_ksyms) + /* Do not show address for interpreted programs */ + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "%+d", insn->off); + else if (sym) snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), "%+d#%s", insn->off, sym->name); else @@ -203,6 +207,10 @@ static const char *print_call(void *private_data, unsigned long address = dd->address_call_base + insn->imm; struct kernel_sym *sym; + if (insn->src_reg == BPF_PSEUDO_CALL && + (__u32) insn->imm < dd->nr_jited_ksyms) + address = dd->jited_ksyms[insn->imm]; + sym = kernel_syms_search(dd, address); if (insn->src_reg == BPF_PSEUDO_CALL) return print_call_pcrel(dd, sym, address, insn); diff --git a/tools/bpf/bpftool/xlated_dumper.h b/tools/bpf/bpftool/xlated_dumper.h index b34affa7ef2d..33d86e2b369b 100644 --- a/tools/bpf/bpftool/xlated_dumper.h +++ b/tools/bpf/bpftool/xlated_dumper.h @@ -49,11 +49,14 @@ struct dump_data { unsigned long address_call_base; struct kernel_sym *sym_mapping; __u32 sym_count; + __u64 *jited_ksyms; + __u32 nr_jited_ksyms; char scratch_buff[SYM_MAX_NAME + 8]; }; void kernel_syms_load(struct dump_data *dd); void kernel_syms_destroy(struct dump_data *dd); +struct kernel_sym *kernel_syms_search(struct dump_data *dd, unsigned long key); void dump_xlated_json(struct dump_data *dd, void *buf, unsigned int len, bool opcodes); void dump_xlated_plain(struct dump_data *dd, void *buf, unsigned int len, diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index c3e502d06bc3..344d2ddcef49 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -2205,6 +2205,10 @@ struct bpf_prog_info { __u32 gpl_compatible:1; __u64 netns_dev; __u64 netns_ino; + __u32 nr_jited_ksyms; + __u32 nr_jited_func_lens; + __aligned_u64 jited_ksyms; + __aligned_u64 jited_func_lens; } __attribute__((aligned(8))); struct bpf_map_info { |