diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/net/bpf_jit.S | 20 | ||||
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 58 |
2 files changed, 40 insertions, 38 deletions
diff --git a/arch/x86/net/bpf_jit.S b/arch/x86/net/bpf_jit.S index f2a7faf4706e..b33093f84528 100644 --- a/arch/x86/net/bpf_jit.S +++ b/arch/x86/net/bpf_jit.S @@ -19,9 +19,6 @@ */ #define SKBDATA %r10 #define SKF_MAX_NEG_OFF $(-0x200000) /* SKF_LL_OFF from filter.h */ -#define MAX_BPF_STACK (512 /* from filter.h */ + \ - 32 /* space for rbx,r13,r14,r15 */ + \ - 8 /* space for skb_copy_bits */) #define FUNC(name) \ .globl name; \ @@ -66,7 +63,7 @@ FUNC(sk_load_byte_positive_offset) /* rsi contains offset and can be scratched */ #define bpf_slow_path_common(LEN) \ - lea -MAX_BPF_STACK + 32(%rbp), %rdx;\ + lea 32(%rbp), %rdx;\ FRAME_BEGIN; \ mov %rbx, %rdi; /* arg1 == skb */ \ push %r9; \ @@ -83,14 +80,14 @@ FUNC(sk_load_byte_positive_offset) bpf_slow_path_word: bpf_slow_path_common(4) js bpf_error - mov - MAX_BPF_STACK + 32(%rbp),%eax + mov 32(%rbp),%eax bswap %eax ret bpf_slow_path_half: bpf_slow_path_common(2) js bpf_error - mov - MAX_BPF_STACK + 32(%rbp),%ax + mov 32(%rbp),%ax rol $8,%ax movzwl %ax,%eax ret @@ -98,7 +95,7 @@ bpf_slow_path_half: bpf_slow_path_byte: bpf_slow_path_common(1) js bpf_error - movzbl - MAX_BPF_STACK + 32(%rbp),%eax + movzbl 32(%rbp),%eax ret #define sk_negative_common(SIZE) \ @@ -148,9 +145,10 @@ FUNC(sk_load_byte_negative_offset) bpf_error: # force a return 0 from jit handler xor %eax,%eax - mov - MAX_BPF_STACK(%rbp),%rbx - mov - MAX_BPF_STACK + 8(%rbp),%r13 - mov - MAX_BPF_STACK + 16(%rbp),%r14 - mov - MAX_BPF_STACK + 24(%rbp),%r15 + mov (%rbp),%rbx + mov 8(%rbp),%r13 + mov 16(%rbp),%r14 + mov 24(%rbp),%r15 + add $40, %rbp leaveq ret diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index fec12eaa0dec..c96dac838f3e 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -197,12 +197,11 @@ 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 @@ -215,13 +214,16 @@ 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, MAX_BPF_STACK + AUX_STACK_SPACE */ + EMIT3_off32(0x48, 0x81, 0xEC, MAX_BPF_STACK + 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 +233,12 @@ 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 +248,8 @@ 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 +291,13 @@ 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(...)] */ @@ -1036,15 +1038,17 @@ 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; |