From: Tonghao Zhang <xxmy@xxxxxxxxxxxxx> The x86_64 can't dump the valid insn in this way. A test BPF prog which include subprog: $ llvm-objdump -d subprog.o Disassembly of section .text: 0000000000000000 <subprog>: 0: 18 01 00 00 73 75 62 70 00 00 00 00 72 6f 67 00 r1 = 29114459903653235 ll 2: 7b 1a f8 ff 00 00 00 00 *(u64 *)(r10 - 8) = r1 3: bf a1 00 00 00 00 00 00 r1 = r10 4: 07 01 00 00 f8 ff ff ff r1 += -8 5: b7 02 00 00 08 00 00 00 r2 = 8 6: 85 00 00 00 06 00 00 00 call 6 7: 95 00 00 00 00 00 00 00 exit Disassembly of section raw_tp/sys_enter: 0000000000000000 <entry>: 0: 85 10 00 00 ff ff ff ff call -1 1: b7 00 00 00 00 00 00 00 r0 = 0 2: 95 00 00 00 00 00 00 00 exit kernel print message: [ 580.775387] flen=8 proglen=51 pass=3 image=ffffffffa000c20c from=kprobe-load pid=1643 [ 580.777236] JIT code: 00000000: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc [ 580.779037] JIT code: 00000010: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc [ 580.780767] JIT code: 00000020: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc [ 580.782568] JIT code: 00000030: cc cc cc $ bpf_jit_disasm 51 bytes emitted from JIT compiler (pass:3, flen:8) ffffffffa000c20c + <x>: 0: int3 1: int3 2: int3 3: int3 4: int3 5: int3 ... Until bpf_jit_binary_pack_finalize is invoked, we copy rw_header to header and then image/insn is valid. BTW, we can use the "bpftool prog dump" JITed instructions. * clean up the doc * remove bpf_jit_disasm tool * set bpf_jit_enable only 0 or 1. Signed-off-by: Tonghao Zhang <xxmy@xxxxxxxxxxxxx> Suggested-by: Alexei Starovoitov <ast@xxxxxxxxxx> Cc: Alexei Starovoitov <ast@xxxxxxxxxx> Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Cc: Andrii Nakryiko <andrii@xxxxxxxxxx> Cc: Martin KaFai Lau <martin.lau@xxxxxxxxx> Cc: Song Liu <song@xxxxxxxxxx> Cc: Yonghong Song <yhs@xxxxxx> Cc: John Fastabend <john.fastabend@xxxxxxxxx> Cc: KP Singh <kpsingh@xxxxxxxxxx> Cc: Stanislav Fomichev <sdf@xxxxxxxxxx> Cc: Hao Luo <haoluo@xxxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: Hou Tao <houtao1@xxxxxxxxxx> --- Documentation/admin-guide/sysctl/net.rst | 2 +- Documentation/networking/filter.rst | 98 +------ arch/arm/net/bpf_jit_32.c | 4 - arch/arm64/net/bpf_jit_comp.c | 4 - arch/loongarch/net/bpf_jit.c | 4 - arch/mips/net/bpf_jit_comp.c | 3 - arch/powerpc/net/bpf_jit_comp.c | 11 - arch/riscv/net/bpf_jit_core.c | 3 - arch/s390/net/bpf_jit_comp.c | 4 - arch/sparc/net/bpf_jit_comp_32.c | 3 - arch/sparc/net/bpf_jit_comp_64.c | 13 - arch/x86/net/bpf_jit_comp.c | 3 - arch/x86/net/bpf_jit_comp32.c | 3 - net/core/sysctl_net_core.c | 14 +- tools/bpf/.gitignore | 1 - tools/bpf/Makefile | 10 +- tools/bpf/bpf_jit_disasm.c | 332 ----------------------- 17 files changed, 8 insertions(+), 504 deletions(-) delete mode 100644 tools/bpf/bpf_jit_disasm.c diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst index 6394f5dc2303..45d3d965276c 100644 --- a/Documentation/admin-guide/sysctl/net.rst +++ b/Documentation/admin-guide/sysctl/net.rst @@ -87,7 +87,7 @@ Values: - 0 - disable the JIT (default value) - 1 - enable the JIT - - 2 - enable the JIT and ask the compiler to emit traces on kernel log. + - 2 - deprecated in linux 6.2 bpf_jit_harden -------------- diff --git a/Documentation/networking/filter.rst b/Documentation/networking/filter.rst index f69da5074860..5f51c050e88f 100644 --- a/Documentation/networking/filter.rst +++ b/Documentation/networking/filter.rst @@ -520,102 +520,8 @@ been previously enabled by root:: echo 1 > /proc/sys/net/core/bpf_jit_enable -For JIT developers, doing audits etc, each compile run can output the generated -opcode image into the kernel log via:: - - echo 2 > /proc/sys/net/core/bpf_jit_enable - -Example output from dmesg:: - - [ 3389.935842] flen=6 proglen=70 pass=3 image=ffffffffa0069c8f - [ 3389.935847] JIT code: 00000000: 55 48 89 e5 48 83 ec 60 48 89 5d f8 44 8b 4f 68 - [ 3389.935849] JIT code: 00000010: 44 2b 4f 6c 4c 8b 87 d8 00 00 00 be 0c 00 00 00 - [ 3389.935850] JIT code: 00000020: e8 1d 94 ff e0 3d 00 08 00 00 75 16 be 17 00 00 - [ 3389.935851] JIT code: 00000030: 00 e8 28 94 ff e0 83 f8 01 75 07 b8 ff ff 00 00 - [ 3389.935852] JIT code: 00000040: eb 02 31 c0 c9 c3 - -When CONFIG_BPF_JIT_ALWAYS_ON is enabled, bpf_jit_enable is permanently set to 1 and -setting any other value than that will return in failure. This is even the case for -setting bpf_jit_enable to 2, since dumping the final JIT image into the kernel log -is discouraged and introspection through bpftool (under tools/bpf/bpftool/) is the -generally recommended approach instead. - -In the kernel source tree under tools/bpf/, there's bpf_jit_disasm for -generating disassembly out of the kernel log's hexdump:: - - # ./bpf_jit_disasm - 70 bytes emitted from JIT compiler (pass:3, flen:6) - ffffffffa0069c8f + <x>: - 0: push %rbp - 1: mov %rsp,%rbp - 4: sub $0x60,%rsp - 8: mov %rbx,-0x8(%rbp) - c: mov 0x68(%rdi),%r9d - 10: sub 0x6c(%rdi),%r9d - 14: mov 0xd8(%rdi),%r8 - 1b: mov $0xc,%esi - 20: callq 0xffffffffe0ff9442 - 25: cmp $0x800,%eax - 2a: jne 0x0000000000000042 - 2c: mov $0x17,%esi - 31: callq 0xffffffffe0ff945e - 36: cmp $0x1,%eax - 39: jne 0x0000000000000042 - 3b: mov $0xffff,%eax - 40: jmp 0x0000000000000044 - 42: xor %eax,%eax - 44: leaveq - 45: retq - - Issuing option `-o` will "annotate" opcodes to resulting assembler - instructions, which can be very useful for JIT developers: - - # ./bpf_jit_disasm -o - 70 bytes emitted from JIT compiler (pass:3, flen:6) - ffffffffa0069c8f + <x>: - 0: push %rbp - 55 - 1: mov %rsp,%rbp - 48 89 e5 - 4: sub $0x60,%rsp - 48 83 ec 60 - 8: mov %rbx,-0x8(%rbp) - 48 89 5d f8 - c: mov 0x68(%rdi),%r9d - 44 8b 4f 68 - 10: sub 0x6c(%rdi),%r9d - 44 2b 4f 6c - 14: mov 0xd8(%rdi),%r8 - 4c 8b 87 d8 00 00 00 - 1b: mov $0xc,%esi - be 0c 00 00 00 - 20: callq 0xffffffffe0ff9442 - e8 1d 94 ff e0 - 25: cmp $0x800,%eax - 3d 00 08 00 00 - 2a: jne 0x0000000000000042 - 75 16 - 2c: mov $0x17,%esi - be 17 00 00 00 - 31: callq 0xffffffffe0ff945e - e8 28 94 ff e0 - 36: cmp $0x1,%eax - 83 f8 01 - 39: jne 0x0000000000000042 - 75 07 - 3b: mov $0xffff,%eax - b8 ff ff 00 00 - 40: jmp 0x0000000000000044 - eb 02 - 42: xor %eax,%eax - 31 c0 - 44: leaveq - c9 - 45: retq - c3 - -For BPF JIT developers, bpf_jit_disasm, bpf_asm and bpf_dbg provides a useful -toolchain for developing and testing the kernel's JIT compiler. +For JIT developers, doing audits etc, should use `bpftool prog dump` to +veiw the JIT generated opcode image. BPF kernel internals -------------------- diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index 6a1c9fca5260..39301d59b537 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -1999,10 +1999,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) } flush_icache_range((u32)header, (u32)(ctx.target + ctx.idx)); - if (bpf_jit_enable > 1) - /* there are 2 passes here */ - bpf_jit_dump(prog->len, image_size, 2, ctx.target); - bpf_jit_binary_lock_ro(header); prog->bpf_func = (void *)ctx.target; prog->jited = 1; diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 62f805f427b7..59c35b4d77b7 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -1567,10 +1567,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) goto out_off; } - /* And we're done. */ - if (bpf_jit_enable > 1) - bpf_jit_dump(prog->len, prog_size, 2, ctx.image); - bpf_flush_icache(header, ctx.image + ctx.idx); if (!prog->is_func || extra_pass) { diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c index bdcd0c7719a9..ea37f52faa6e 100644 --- a/arch/loongarch/net/bpf_jit.c +++ b/arch/loongarch/net/bpf_jit.c @@ -1123,10 +1123,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) goto out_offset; } - /* And we're done */ - if (bpf_jit_enable > 1) - bpf_jit_dump(prog->len, image_size, 2, ctx.image); - /* Update the icache */ flush_icache_range((unsigned long)header, (unsigned long)(ctx.image + ctx.idx)); diff --git a/arch/mips/net/bpf_jit_comp.c b/arch/mips/net/bpf_jit_comp.c index b17130d510d4..ccbb7c231cb0 100644 --- a/arch/mips/net/bpf_jit_comp.c +++ b/arch/mips/net/bpf_jit_comp.c @@ -1012,9 +1012,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) flush_icache_range((unsigned long)header, (unsigned long)&ctx.target[ctx.jit_index]); - if (bpf_jit_enable > 1) - bpf_jit_dump(prog->len, image_size, 2, ctx.target); - prog->bpf_func = (void *)ctx.target; prog->jited = 1; prog->jited_len = image_size; diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c index 43e634126514..f0f7d8ff2022 100644 --- a/arch/powerpc/net/bpf_jit_comp.c +++ b/arch/powerpc/net/bpf_jit_comp.c @@ -262,20 +262,9 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) goto out_addrs; } bpf_jit_build_epilogue(code_base, &cgctx); - - if (bpf_jit_enable > 1) - pr_info("Pass %d: shrink = %d, seen = 0x%x\n", pass, - proglen - (cgctx.idx * 4), cgctx.seen); } skip_codegen_passes: - if (bpf_jit_enable > 1) - /* - * Note that we output the base address of the code_base - * rather than image, since opcodes are in code_base. - */ - bpf_jit_dump(flen, proglen, pass, code_base); - #ifdef CONFIG_PPC64_ELF_ABI_V1 /* Function descriptor nastiness: Address + TOC */ ((u64 *)image)[0] = (u64)code_base; diff --git a/arch/riscv/net/bpf_jit_core.c b/arch/riscv/net/bpf_jit_core.c index 737baf8715da..ff168c50d46a 100644 --- a/arch/riscv/net/bpf_jit_core.c +++ b/arch/riscv/net/bpf_jit_core.c @@ -151,9 +151,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) } bpf_jit_build_epilogue(ctx); - if (bpf_jit_enable > 1) - bpf_jit_dump(prog->len, prog_size, pass, ctx->insns); - prog->bpf_func = (void *)ctx->insns; prog->jited = 1; prog->jited_len = prog_size; diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index af35052d06ed..13d996e27602 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -1831,10 +1831,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) fp = orig_fp; goto free_addrs; } - if (bpf_jit_enable > 1) { - bpf_jit_dump(fp->len, jit.size, pass, jit.prg_buf); - print_fn_code(jit.prg_buf, jit.size_prg); - } if (!fp->is_func || extra_pass) { bpf_jit_binary_lock_ro(header); } else { diff --git a/arch/sparc/net/bpf_jit_comp_32.c b/arch/sparc/net/bpf_jit_comp_32.c index a74e5004c6c8..08de0ed84831 100644 --- a/arch/sparc/net/bpf_jit_comp_32.c +++ b/arch/sparc/net/bpf_jit_comp_32.c @@ -743,9 +743,6 @@ cond_branch: f_offset = addrs[i + filter[i].jf]; oldproglen = proglen; } - if (bpf_jit_enable > 1) - bpf_jit_dump(flen, proglen, pass + 1, image); - if (image) { fp->bpf_func = (void *)image; fp->jited = 1; diff --git a/arch/sparc/net/bpf_jit_comp_64.c b/arch/sparc/net/bpf_jit_comp_64.c index fa0759bfe498..14c9e5ce4100 100644 --- a/arch/sparc/net/bpf_jit_comp_64.c +++ b/arch/sparc/net/bpf_jit_comp_64.c @@ -1549,16 +1549,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) } build_epilogue(&ctx); - if (bpf_jit_enable > 1) - pr_info("Pass %d: size = %u, seen = [%c%c%c%c%c%c]\n", pass, - ctx.idx * 4, - ctx.tmp_1_used ? '1' : ' ', - ctx.tmp_2_used ? '2' : ' ', - ctx.tmp_3_used ? '3' : ' ', - ctx.saw_frame_pointer ? 'F' : ' ', - ctx.saw_call ? 'C' : ' ', - ctx.saw_tail_call ? 'T' : ' '); - if (ctx.idx * 4 == prev_image_size) break; prev_image_size = ctx.idx * 4; @@ -1596,9 +1586,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) goto out_off; } - if (bpf_jit_enable > 1) - bpf_jit_dump(prog->len, image_size, pass, ctx.image); - bpf_flush_icache(header, (u8 *)header + header->size); if (!prog->is_func || extra_pass) { diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index e3e2b57e4e13..197ff8651a56 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -2551,9 +2551,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) cond_resched(); } - if (bpf_jit_enable > 1) - bpf_jit_dump(prog->len, proglen, pass + 1, image); - if (image) { if (!prog->is_func || extra_pass) { /* diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c index 429a89c5468b..ca53f20aca73 100644 --- a/arch/x86/net/bpf_jit_comp32.c +++ b/arch/x86/net/bpf_jit_comp32.c @@ -2597,9 +2597,6 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) cond_resched(); } - if (bpf_jit_enable > 1) - bpf_jit_dump(prog->len, proglen, pass + 1, image); - if (image) { bpf_jit_binary_lock_ro(header); prog->bpf_func = (void *)image; diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 5b1ce656baa1..731a2eb0f68e 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -275,16 +275,8 @@ static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write, tmp.data = &jit_enable; ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos); - if (write && !ret) { - if (jit_enable < 2 || - (jit_enable == 2 && bpf_dump_raw_ok(current_cred()))) { - *(int *)table->data = jit_enable; - if (jit_enable == 2) - pr_warn("bpf_jit_enable = 2 was set! NEVER use this in production, only for JIT debugging!\n"); - } else { - ret = -EPERM; - } - } + if (write && !ret) + *(int *)table->data = jit_enable; if (write && ret && min == max) pr_info_once("CONFIG_BPF_JIT_ALWAYS_ON is enabled, bpf_jit_enable is permanently set to 1.\n"); @@ -395,7 +387,7 @@ static struct ctl_table net_core_table[] = { .extra2 = SYSCTL_ONE, # else .extra1 = SYSCTL_ZERO, - .extra2 = SYSCTL_TWO, + .extra2 = SYSCTL_ONE, # endif }, # ifdef CONFIG_HAVE_EBPF_JIT diff --git a/tools/bpf/.gitignore b/tools/bpf/.gitignore index cf53342175e7..5c70cfb9092e 100644 --- a/tools/bpf/.gitignore +++ b/tools/bpf/.gitignore @@ -4,4 +4,3 @@ feature bpf_asm bpf_dbg bpf_exp.yacc.* -bpf_jit_disasm diff --git a/tools/bpf/Makefile b/tools/bpf/Makefile index 243b79f2b451..9264d7b0edf6 100644 --- a/tools/bpf/Makefile +++ b/tools/bpf/Makefile @@ -74,14 +74,10 @@ $(OUTPUT)%.yacc.o: $(OUTPUT)%.yacc.c $(OUTPUT)%.lex.o: $(OUTPUT)%.lex.c $(QUIET_CC)$(CC) $(CFLAGS) -c -o $@ $< -PROGS = $(OUTPUT)bpf_jit_disasm $(OUTPUT)bpf_dbg $(OUTPUT)bpf_asm +PROGS = $(OUTPUT)bpf_dbg $(OUTPUT)bpf_asm all: $(PROGS) bpftool runqslower -$(OUTPUT)bpf_jit_disasm: CFLAGS += -DPACKAGE='bpf_jit_disasm' -$(OUTPUT)bpf_jit_disasm: $(OUTPUT)bpf_jit_disasm.o - $(QUIET_LINK)$(CC) $(CFLAGS) -o $@ $^ -lopcodes -lbfd -ldl - $(OUTPUT)bpf_dbg: $(OUTPUT)bpf_dbg.o $(QUIET_LINK)$(CC) $(CFLAGS) -o $@ $^ -lreadline @@ -94,16 +90,14 @@ $(OUTPUT)bpf_exp.lex.o: $(OUTPUT)bpf_exp.lex.c clean: bpftool_clean runqslower_clean resolve_btfids_clean $(call QUIET_CLEAN, bpf-progs) - $(Q)$(RM) -r -- $(OUTPUT)*.o $(OUTPUT)bpf_jit_disasm $(OUTPUT)bpf_dbg \ + $(Q)$(RM) -r -- $(OUTPUT)*.o $(OUTPUT)bpf_dbg \ $(OUTPUT)bpf_asm $(OUTPUT)bpf_exp.yacc.* $(OUTPUT)bpf_exp.lex.* $(call QUIET_CLEAN, core-gen) $(Q)$(RM) -- $(OUTPUT)FEATURE-DUMP.bpf $(Q)$(RM) -r -- $(OUTPUT)feature install: $(PROGS) bpftool_install - $(call QUIET_INSTALL, bpf_jit_disasm) $(Q)$(INSTALL) -m 0755 -d $(DESTDIR)$(prefix)/bin - $(Q)$(INSTALL) $(OUTPUT)bpf_jit_disasm $(DESTDIR)$(prefix)/bin/bpf_jit_disasm $(call QUIET_INSTALL, bpf_dbg) $(Q)$(INSTALL) $(OUTPUT)bpf_dbg $(DESTDIR)$(prefix)/bin/bpf_dbg $(call QUIET_INSTALL, bpf_asm) diff --git a/tools/bpf/bpf_jit_disasm.c b/tools/bpf/bpf_jit_disasm.c deleted file mode 100644 index a90a5d110f92..000000000000 --- a/tools/bpf/bpf_jit_disasm.c +++ /dev/null @@ -1,332 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -/* - * Minimal BPF JIT image disassembler - * - * Disassembles BPF JIT compiler emitted opcodes back to asm insn's for - * debugging or verification purposes. - * - * To get the disassembly of the JIT code, do the following: - * - * 1) `echo 2 > /proc/sys/net/core/bpf_jit_enable` - * 2) Load a BPF filter (e.g. `tcpdump -p -n -s 0 -i eth1 host 192.168.20.0/24`) - * 3) Run e.g. `bpf_jit_disasm -o` to read out the last JIT code - * - * Copyright 2013 Daniel Borkmann <borkmann@xxxxxxxxxx> - */ - -#include <stdint.h> -#include <stdio.h> -#include <stdlib.h> -#include <assert.h> -#include <unistd.h> -#include <string.h> -#include <bfd.h> -#include <dis-asm.h> -#include <regex.h> -#include <fcntl.h> -#include <sys/klog.h> -#include <sys/types.h> -#include <sys/stat.h> -#include <limits.h> -#include <tools/dis-asm-compat.h> - -#define CMD_ACTION_SIZE_BUFFER 10 -#define CMD_ACTION_READ_ALL 3 - -static void get_exec_path(char *tpath, size_t size) -{ - char *path; - ssize_t len; - - snprintf(tpath, size, "/proc/%d/exe", (int) getpid()); - tpath[size - 1] = 0; - - path = strdup(tpath); - assert(path); - - len = readlink(path, tpath, size); - tpath[len] = 0; - - free(path); -} - -static void get_asm_insns(uint8_t *image, size_t len, int opcodes) -{ - int count, i, pc = 0; - char tpath[PATH_MAX]; - struct disassemble_info info; - disassembler_ftype disassemble; - bfd *bfdf; - - memset(tpath, 0, sizeof(tpath)); - get_exec_path(tpath, sizeof(tpath)); - - bfdf = bfd_openr(tpath, NULL); - assert(bfdf); - assert(bfd_check_format(bfdf, bfd_object)); - - init_disassemble_info_compat(&info, stdout, - (fprintf_ftype) fprintf, - fprintf_styled); - info.arch = bfd_get_arch(bfdf); - info.mach = bfd_get_mach(bfdf); - info.buffer = image; - info.buffer_length = len; - - 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 - assert(disassemble); - - do { - printf("%4x:\t", pc); - - count = disassemble(pc, &info); - - if (opcodes) { - printf("\n\t"); - for (i = 0; i < count; ++i) - printf("%02x ", (uint8_t) image[pc + i]); - } - printf("\n"); - - pc += count; - } while(count > 0 && pc < len); - - bfd_close(bfdf); -} - -static char *get_klog_buff(unsigned int *klen) -{ - int ret, len; - char *buff; - - len = klogctl(CMD_ACTION_SIZE_BUFFER, NULL, 0); - if (len < 0) - return NULL; - - buff = malloc(len); - if (!buff) - return NULL; - - ret = klogctl(CMD_ACTION_READ_ALL, buff, len); - if (ret < 0) { - free(buff); - return NULL; - } - - *klen = ret; - return buff; -} - -static char *get_flog_buff(const char *file, unsigned int *klen) -{ - int fd, ret, len; - struct stat fi; - char *buff; - - fd = open(file, O_RDONLY); - if (fd < 0) - return NULL; - - ret = fstat(fd, &fi); - if (ret < 0 || !S_ISREG(fi.st_mode)) - goto out; - - len = fi.st_size + 1; - buff = malloc(len); - if (!buff) - goto out; - - memset(buff, 0, len); - ret = read(fd, buff, len - 1); - if (ret <= 0) - goto out_free; - - close(fd); - *klen = ret; - return buff; -out_free: - free(buff); -out: - close(fd); - return NULL; -} - -static char *get_log_buff(const char *file, unsigned int *klen) -{ - return file ? get_flog_buff(file, klen) : get_klog_buff(klen); -} - -static void put_log_buff(char *buff) -{ - free(buff); -} - -static uint8_t *get_last_jit_image(char *haystack, size_t hlen, - unsigned int *ilen) -{ - char *ptr, *pptr, *tmp; - off_t off = 0; - unsigned int proglen; - int ret, flen, pass, ulen = 0; - regmatch_t pmatch[1]; - unsigned long base; - regex_t regex; - uint8_t *image; - - if (hlen == 0) - return NULL; - - ret = regcomp(®ex, "flen=[[:alnum:]]+ proglen=[[:digit:]]+ " - "pass=[[:digit:]]+ image=[[:xdigit:]]+", REG_EXTENDED); - assert(ret == 0); - - ptr = haystack; - memset(pmatch, 0, sizeof(pmatch)); - - while (1) { - ret = regexec(®ex, ptr, 1, pmatch, 0); - if (ret == 0) { - ptr += pmatch[0].rm_eo; - off += pmatch[0].rm_eo; - assert(off < hlen); - } else - break; - } - - ptr = haystack + off - (pmatch[0].rm_eo - pmatch[0].rm_so); - ret = sscanf(ptr, "flen=%d proglen=%u pass=%d image=%lx", - &flen, &proglen, &pass, &base); - if (ret != 4) { - regfree(®ex); - return NULL; - } - if (proglen > 1000000) { - printf("proglen of %d too big, stopping\n", proglen); - return NULL; - } - - image = malloc(proglen); - if (!image) { - printf("Out of memory\n"); - return NULL; - } - memset(image, 0, proglen); - - tmp = ptr = haystack + off; - while ((ptr = strtok(tmp, "\n")) != NULL && ulen < proglen) { - tmp = NULL; - if (!strstr(ptr, "JIT code")) - continue; - pptr = ptr; - while ((ptr = strstr(pptr, ":"))) - pptr = ptr + 1; - ptr = pptr; - do { - image[ulen++] = (uint8_t) strtoul(pptr, &pptr, 16); - if (ptr == pptr) { - ulen--; - break; - } - if (ulen >= proglen) - break; - ptr = pptr; - } while (1); - } - - assert(ulen == proglen); - printf("%u bytes emitted from JIT compiler (pass:%d, flen:%d)\n", - proglen, pass, flen); - printf("%lx + <x>:\n", base); - - regfree(®ex); - *ilen = ulen; - return image; -} - -static void usage(void) -{ - printf("Usage: bpf_jit_disasm [...]\n"); - printf(" -o Also display related opcodes (default: off).\n"); - printf(" -O <file> Write binary image of code to file, don't disassemble to stdout.\n"); - printf(" -f <file> Read last image dump from file or stdin (default: klog).\n"); - printf(" -h Display this help.\n"); -} - -int main(int argc, char **argv) -{ - unsigned int len, klen, opt, opcodes = 0; - char *kbuff, *file = NULL; - char *ofile = NULL; - int ofd; - ssize_t nr; - uint8_t *pos; - uint8_t *image = NULL; - - while ((opt = getopt(argc, argv, "of:O:")) != -1) { - switch (opt) { - case 'o': - opcodes = 1; - break; - case 'O': - ofile = optarg; - break; - case 'f': - file = optarg; - break; - default: - usage(); - return -1; - } - } - - bfd_init(); - - kbuff = get_log_buff(file, &klen); - if (!kbuff) { - fprintf(stderr, "Could not retrieve log buffer!\n"); - return -1; - } - - image = get_last_jit_image(kbuff, klen, &len); - if (!image) { - fprintf(stderr, "No JIT image found!\n"); - goto done; - } - if (!ofile) { - get_asm_insns(image, len, opcodes); - goto done; - } - - ofd = open(ofile, O_WRONLY | O_CREAT | O_TRUNC, DEFFILEMODE); - if (ofd < 0) { - fprintf(stderr, "Could not open file %s for writing: ", ofile); - perror(NULL); - goto done; - } - pos = image; - do { - nr = write(ofd, pos, len); - if (nr < 0) { - fprintf(stderr, "Could not write data to %s: ", ofile); - perror(NULL); - goto done; - } - len -= nr; - pos += nr; - } while (len); - close(ofd); - -done: - put_log_buff(kbuff); - free(image); - return 0; -} -- 2.27.0