diff options
Diffstat (limited to 'arch/x86/net/bpf_jit_comp.c')
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 66 |
1 files changed, 36 insertions, 30 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index f58939393eef..e1324f280e06 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -197,17 +197,16 @@ struct jit_context { #define BPF_MAX_INSN_SIZE 128 #define BPF_INSN_SAFETY 64 -#define STACKSIZE \ - (MAX_BPF_STACK + \ - 32 /* space for rbx, r13, r14, r15 */ + \ +#define AUX_STACK_SPACE \ + (32 /* space for rbx, r13, r14, r15 */ + \ 8 /* space for skb_copy_bits() buffer */) -#define PROLOGUE_SIZE 48 +#define PROLOGUE_SIZE 37 /* emit x64 prologue code for BPF program and check it's size. * bpf_tail_call helper will skip it while jumping into another program */ -static void emit_prologue(u8 **pprog) +static void emit_prologue(u8 **pprog, u32 stack_depth) { u8 *prog = *pprog; int cnt = 0; @@ -215,13 +214,17 @@ static void emit_prologue(u8 **pprog) EMIT1(0x55); /* push rbp */ EMIT3(0x48, 0x89, 0xE5); /* mov rbp,rsp */ - /* sub rsp, STACKSIZE */ - EMIT3_off32(0x48, 0x81, 0xEC, STACKSIZE); + /* sub rsp, rounded_stack_depth + AUX_STACK_SPACE */ + EMIT3_off32(0x48, 0x81, 0xEC, + round_up(stack_depth, 8) + AUX_STACK_SPACE); + + /* sub rbp, AUX_STACK_SPACE */ + EMIT4(0x48, 0x83, 0xED, AUX_STACK_SPACE); /* all classic BPF filters use R6(rbx) save it */ - /* mov qword ptr [rbp-X],rbx */ - EMIT3_off32(0x48, 0x89, 0x9D, -STACKSIZE); + /* mov qword ptr [rbp+0],rbx */ + EMIT4(0x48, 0x89, 0x5D, 0); /* bpf_convert_filter() maps classic BPF register X to R7 and uses R8 * as temporary, so all tcpdump filters need to spill/fill R7(r13) and @@ -231,12 +234,12 @@ static void emit_prologue(u8 **pprog) * than synthetic ones. Therefore not worth adding complexity. */ - /* mov qword ptr [rbp-X],r13 */ - EMIT3_off32(0x4C, 0x89, 0xAD, -STACKSIZE + 8); - /* mov qword ptr [rbp-X],r14 */ - EMIT3_off32(0x4C, 0x89, 0xB5, -STACKSIZE + 16); - /* mov qword ptr [rbp-X],r15 */ - EMIT3_off32(0x4C, 0x89, 0xBD, -STACKSIZE + 24); + /* mov qword ptr [rbp+8],r13 */ + EMIT4(0x4C, 0x89, 0x6D, 8); + /* mov qword ptr [rbp+16],r14 */ + EMIT4(0x4C, 0x89, 0x75, 16); + /* mov qword ptr [rbp+24],r15 */ + EMIT4(0x4C, 0x89, 0x7D, 24); /* Clear the tail call counter (tail_call_cnt): for eBPF tail calls * we need to reset the counter to 0. It's done in two instructions, @@ -246,8 +249,8 @@ static void emit_prologue(u8 **pprog) /* xor eax, eax */ EMIT2(0x31, 0xc0); - /* mov qword ptr [rbp-X], rax */ - EMIT3_off32(0x48, 0x89, 0x85, -STACKSIZE + 32); + /* mov qword ptr [rbp+32], rax */ + EMIT4(0x48, 0x89, 0x45, 32); BUILD_BUG_ON(cnt != PROLOGUE_SIZE); *pprog = prog; @@ -289,13 +292,13 @@ static void emit_bpf_tail_call(u8 **pprog) /* if (tail_call_cnt > MAX_TAIL_CALL_CNT) * goto out; */ - EMIT2_off32(0x8B, 0x85, -STACKSIZE + 36); /* mov eax, dword ptr [rbp - 516] */ + EMIT2_off32(0x8B, 0x85, 36); /* mov eax, dword ptr [rbp + 36] */ EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */ #define OFFSET2 36 EMIT2(X86_JA, OFFSET2); /* ja out */ label2 = cnt; EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */ - EMIT2_off32(0x89, 0x85, -STACKSIZE + 36); /* mov dword ptr [rbp - 516], eax */ + EMIT2_off32(0x89, 0x85, 36); /* mov dword ptr [rbp + 36], eax */ /* prog = array->ptrs[index]; */ EMIT4_off32(0x48, 0x8D, 0x84, 0xD6, /* lea rax, [rsi + rdx * 8 + offsetof(...)] */ @@ -361,7 +364,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, int proglen = 0; u8 *prog = temp; - emit_prologue(&prog); + emit_prologue(&prog, bpf_prog->aux->stack_depth); if (seen_ld_abs) emit_load_skb_data_hlen(&prog); @@ -877,7 +880,7 @@ xadd: if (is_imm8(insn->off)) } break; - case BPF_JMP | BPF_CALL | BPF_X: + case BPF_JMP | BPF_TAIL_CALL: emit_bpf_tail_call(&prog); break; @@ -1036,15 +1039,17 @@ common_load: seen_exit = true; /* update cleanup_addr */ ctx->cleanup_addr = proglen; - /* mov rbx, qword ptr [rbp-X] */ - EMIT3_off32(0x48, 0x8B, 0x9D, -STACKSIZE); - /* mov r13, qword ptr [rbp-X] */ - EMIT3_off32(0x4C, 0x8B, 0xAD, -STACKSIZE + 8); - /* mov r14, qword ptr [rbp-X] */ - EMIT3_off32(0x4C, 0x8B, 0xB5, -STACKSIZE + 16); - /* mov r15, qword ptr [rbp-X] */ - EMIT3_off32(0x4C, 0x8B, 0xBD, -STACKSIZE + 24); - + /* mov rbx, qword ptr [rbp+0] */ + EMIT4(0x48, 0x8B, 0x5D, 0); + /* mov r13, qword ptr [rbp+8] */ + EMIT4(0x4C, 0x8B, 0x6D, 8); + /* mov r14, qword ptr [rbp+16] */ + EMIT4(0x4C, 0x8B, 0x75, 16); + /* mov r15, qword ptr [rbp+24] */ + EMIT4(0x4C, 0x8B, 0x7D, 24); + + /* add rbp, AUX_STACK_SPACE */ + EMIT4(0x48, 0x83, 0xC5, AUX_STACK_SPACE); EMIT1(0xC9); /* leave */ EMIT1(0xC3); /* ret */ break; @@ -1162,6 +1167,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) bpf_jit_binary_lock_ro(header); prog->bpf_func = (void *)image; prog->jited = 1; + prog->jited_len = proglen; } else { prog = orig_prog; } |