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Commit 1f499d6a authored by David S. Miller's avatar David S. Miller
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Merge branch 'filter-next' 

Alexei Starovoitov says:

====================
internal BPF jit for x64 and JITed seccomp

Internal BPF JIT compiler for x86_64 replaces classic BPF JIT.
Use it in seccomp and in tracing filters (sent as separate patch)
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 9509b1c1 8f577cad
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arch/x86/net/bpf_jit.S
View file @ 1f499d6a
......@@ -12,13 +12,16 @@
/*
* Calling convention :
* rdi : skb pointer
* rbx : skb pointer (callee saved)
* esi : offset of byte(s) to fetch in skb (can be scratched)
* r8 : copy of skb->data
* r10 : copy of skb->data
* r9d : hlen = skb->len - skb->data_len
*/
#define SKBDATA %r8
#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 */)
sk_load_word:
.globl sk_load_word
......@@ -68,53 +71,31 @@ sk_load_byte_positive_offset:
movzbl (SKBDATA,%rsi),%eax
ret
/**
* sk_load_byte_msh - BPF_S_LDX_B_MSH helper
*
* Implements BPF_S_LDX_B_MSH : ldxb 4*([offset]&0xf)
* Must preserve A accumulator (%eax)
* Inputs : %esi is the offset value
*/
sk_load_byte_msh:
.globl sk_load_byte_msh
test %esi,%esi
js bpf_slow_path_byte_msh_neg
sk_load_byte_msh_positive_offset:
.globl sk_load_byte_msh_positive_offset
cmp %esi,%r9d /* if (offset >= hlen) goto bpf_slow_path_byte_msh */
jle bpf_slow_path_byte_msh
movzbl (SKBDATA,%rsi),%ebx
and $15,%bl
shl $2,%bl
ret
/* rsi contains offset and can be scratched */
#define bpf_slow_path_common(LEN) \
push %rdi; /* save skb */ \
mov %rbx, %rdi; /* arg1 == skb */ \
push %r9; \
push SKBDATA; \
/* rsi already has offset */ \
mov $LEN,%ecx; /* len */ \
lea -12(%rbp),%rdx; \
lea - MAX_BPF_STACK + 32(%rbp),%rdx; \
call skb_copy_bits; \
test %eax,%eax; \
pop SKBDATA; \
pop %r9; \
pop %rdi
pop %r9;
bpf_slow_path_word:
bpf_slow_path_common(4)
js bpf_error
mov -12(%rbp),%eax
mov - MAX_BPF_STACK + 32(%rbp),%eax
bswap %eax
ret
bpf_slow_path_half:
bpf_slow_path_common(2)
js bpf_error
mov -12(%rbp),%ax
mov - MAX_BPF_STACK + 32(%rbp),%ax
rol $8,%ax
movzwl %ax,%eax
ret
......@@ -122,21 +103,11 @@ bpf_slow_path_half:
bpf_slow_path_byte:
bpf_slow_path_common(1)
js bpf_error
movzbl -12(%rbp),%eax
ret
bpf_slow_path_byte_msh:
xchg %eax,%ebx /* dont lose A , X is about to be scratched */
bpf_slow_path_common(1)
js bpf_error
movzbl -12(%rbp),%eax
and $15,%al
shl $2,%al
xchg %eax,%ebx
movzbl - MAX_BPF_STACK + 32(%rbp),%eax
ret
#define sk_negative_common(SIZE) \
push %rdi; /* save skb */ \
mov %rbx, %rdi; /* arg1 == skb */ \
push %r9; \
push SKBDATA; \
/* rsi already has offset */ \
......@@ -145,10 +116,8 @@ bpf_slow_path_byte_msh:
test %rax,%rax; \
pop SKBDATA; \
pop %r9; \
pop %rdi; \
jz bpf_error
bpf_slow_path_word_neg:
cmp SKF_MAX_NEG_OFF, %esi /* test range */
jl bpf_error /* offset lower -> error */
......@@ -179,22 +148,12 @@ sk_load_byte_negative_offset:
movzbl (%rax), %eax
ret
bpf_slow_path_byte_msh_neg:
cmp SKF_MAX_NEG_OFF, %esi
jl bpf_error
sk_load_byte_msh_negative_offset:
.globl sk_load_byte_msh_negative_offset
xchg %eax,%ebx /* dont lose A , X is about to be scratched */
sk_negative_common(1)
movzbl (%rax),%eax
and $15,%al
shl $2,%al
xchg %eax,%ebx
ret
bpf_error:
# force a return 0 from jit handler
xor %eax,%eax
mov -8(%rbp),%rbx
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
leaveq
ret
arch/x86/net/bpf_jit_comp.c
View file @ 1f499d6a
/* bpf_jit_comp.c : BPF JIT compiler
*
* Copyright (C) 2011-2013 Eric Dumazet (eric.dumazet@gmail.com)
* Internal BPF Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
......@@ -14,28 +15,16 @@
#include <linux/if_vlan.h>
#include <linux/random.h>
/*
* Conventions :
* EAX : BPF A accumulator
* EBX : BPF X accumulator
* RDI : pointer to skb (first argument given to JIT function)
* RBP : frame pointer (even if CONFIG_FRAME_POINTER=n)
* ECX,EDX,ESI : scratch registers
* r9d : skb->len - skb->data_len (headlen)
* r8 : skb->data
* -8(RBP) : saved RBX value
* -16(RBP)..-80(RBP) : BPF_MEMWORDS values
*/
int bpf_jit_enable __read_mostly;
/*
* assembly code in arch/x86/net/bpf_jit.S
*/
extern u8 sk_load_word[], sk_load_half[], sk_load_byte[], sk_load_byte_msh[];
extern u8 sk_load_word[], sk_load_half[], sk_load_byte[];
extern u8 sk_load_word_positive_offset[], sk_load_half_positive_offset[];
extern u8 sk_load_byte_positive_offset[], sk_load_byte_msh_positive_offset[];
extern u8 sk_load_byte_positive_offset[];
extern u8 sk_load_word_negative_offset[], sk_load_half_negative_offset[];
extern u8 sk_load_byte_negative_offset[], sk_load_byte_msh_negative_offset[];
extern u8 sk_load_byte_negative_offset[];
static inline u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
{
......@@ -56,30 +45,44 @@ static inline u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
#define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2)
#define EMIT3(b1, b2, b3) EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3)
#define EMIT4(b1, b2, b3, b4) EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4)
#define EMIT1_off32(b1, off) do { EMIT1(b1); EMIT(off, 4);} while (0)
#define CLEAR_A() EMIT2(0x31, 0xc0) /* xor %eax,%eax */
#define CLEAR_X() EMIT2(0x31, 0xdb) /* xor %ebx,%ebx */
#define EMIT1_off32(b1, off) \
do {EMIT1(b1); EMIT(off, 4); } while (0)
#define EMIT2_off32(b1, b2, off) \
do {EMIT2(b1, b2); EMIT(off, 4); } while (0)
#define EMIT3_off32(b1, b2, b3, off) \
do {EMIT3(b1, b2, b3); EMIT(off, 4); } while (0)
#define EMIT4_off32(b1, b2, b3, b4, off) \
do {EMIT4(b1, b2, b3, b4); EMIT(off, 4); } while (0)
static inline bool is_imm8(int value)
{
return value <= 127 && value >= -128;
}
static inline bool is_near(int offset)
static inline bool is_simm32(s64 value)
{
return offset <= 127 && offset >= -128;
return value == (s64) (s32) value;
}
#define EMIT_JMP(offset) \
do { \
if (offset) { \
if (is_near(offset)) \
EMIT2(0xeb, offset); /* jmp .+off8 */ \
else \
EMIT1_off32(0xe9, offset); /* jmp .+off32 */ \
} \
} while (0)
/* mov A, X */
#define EMIT_mov(A, X) \
do {if (A != X) \
EMIT3(add_2mod(0x48, A, X), 0x89, add_2reg(0xC0, A, X)); \
} while (0)
static int bpf_size_to_x86_bytes(int bpf_size)
{
if (bpf_size == BPF_W)
return 4;
else if (bpf_size == BPF_H)
return 2;
else if (bpf_size == BPF_B)
return 1;
else if (bpf_size == BPF_DW)
return 4; /* imm32 */
else
return 0;
}
/* list of x86 cond jumps opcodes (. + s8)
* Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32)
......@@ -90,27 +93,8 @@ do { \
#define X86_JNE 0x75
#define X86_JBE 0x76
#define X86_JA 0x77
#define EMIT_COND_JMP(op, offset) \
do { \
if (is_near(offset)) \
EMIT2(op, offset); /* jxx .+off8 */ \
else { \
EMIT2(0x0f, op + 0x10); \
EMIT(offset, 4); /* jxx .+off32 */ \
} \
} while (0)
#define COND_SEL(CODE, TOP, FOP) \
case CODE: \
t_op = TOP; \
f_op = FOP; \
goto cond_branch
#define SEEN_DATAREF 1 /* might call external helpers */
#define SEEN_XREG 2 /* ebx is used */
#define SEEN_MEM 4 /* use mem[] for temporary storage */
#define X86_JGE 0x7D
#define X86_JG 0x7F
static inline void bpf_flush_icache(void *start, void *end)
{
......@@ -125,26 +109,6 @@ static inline void bpf_flush_icache(void *start, void *end)
#define CHOOSE_LOAD_FUNC(K, func) \
((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset)
/* Helper to find the offset of pkt_type in sk_buff
* We want to make sure its still a 3bit field starting at a byte boundary.
*/
#define PKT_TYPE_MAX 7
static int pkt_type_offset(void)
{
struct sk_buff skb_probe = {
.pkt_type = ~0,
};
char *ct = (char *)&skb_probe;
unsigned int off;
for (off = 0; off < sizeof(struct sk_buff); off++) {
if (ct[off] == PKT_TYPE_MAX)
return off;
}
pr_err_once("Please fix pkt_type_offset(), as pkt_type couldn't be found\n");
return -1;
}
struct bpf_binary_header {
unsigned int pages;
/* Note : for security reasons, bpf code will follow a randomly
......@@ -178,564 +142,716 @@ static struct bpf_binary_header *bpf_alloc_binary(unsigned int proglen,
return header;
}
void bpf_jit_compile(struct sk_filter *fp)
/* pick a register outside of BPF range for JIT internal work */
#define AUX_REG (MAX_BPF_REG + 1)
/* the following table maps BPF registers to x64 registers.
* x64 register r12 is unused, since if used as base address register
* in load/store instructions, it always needs an extra byte of encoding
*/
static const int reg2hex[] = {
[BPF_REG_0] = 0, /* rax */
[BPF_REG_1] = 7, /* rdi */
[BPF_REG_2] = 6, /* rsi */
[BPF_REG_3] = 2, /* rdx */
[BPF_REG_4] = 1, /* rcx */
[BPF_REG_5] = 0, /* r8 */
[BPF_REG_6] = 3, /* rbx callee saved */
[BPF_REG_7] = 5, /* r13 callee saved */
[BPF_REG_8] = 6, /* r14 callee saved */
[BPF_REG_9] = 7, /* r15 callee saved */
[BPF_REG_FP] = 5, /* rbp readonly */
[AUX_REG] = 3, /* r11 temp register */
};
/* is_ereg() == true if BPF register 'reg' maps to x64 r8..r15
* which need extra byte of encoding.
* rax,rcx,...,rbp have simpler encoding
*/
static inline bool is_ereg(u32 reg)
{
u8 temp[64];
u8 *prog;
unsigned int proglen, oldproglen = 0;
int ilen, i;
int t_offset, f_offset;
u8 t_op, f_op, seen = 0, pass;
u8 *image = NULL;
struct bpf_binary_header *header = NULL;
u8 *func;
int pc_ret0 = -1; /* bpf index of first RET #0 instruction (if any) */
unsigned int cleanup_addr; /* epilogue code offset */
unsigned int *addrs;
const struct sock_filter *filter = fp->insns;
int flen = fp->len;
if (reg == BPF_REG_5 || reg == AUX_REG ||
(reg >= BPF_REG_7 && reg <= BPF_REG_9))
return true;
else
return false;
}
if (!bpf_jit_enable)
return;
/* add modifiers if 'reg' maps to x64 registers r8..r15 */
static inline u8 add_1mod(u8 byte, u32 reg)
{
if (is_ereg(reg))
byte |= 1;
return byte;
}
addrs = kmalloc(flen * sizeof(*addrs), GFP_KERNEL);
if (addrs == NULL)
return;
static inline u8 add_2mod(u8 byte, u32 r1, u32 r2)
{
if (is_ereg(r1))
byte |= 1;
if (is_ereg(r2))
byte |= 4;
return byte;
}
/* Before first pass, make a rough estimation of addrs[]
* each bpf instruction is translated to less than 64 bytes
/* encode dest register 'a_reg' into x64 opcode 'byte' */
static inline u8 add_1reg(u8 byte, u32 a_reg)
{
return byte + reg2hex[a_reg];
}
/* encode dest 'a_reg' and src 'x_reg' registers into x64 opcode 'byte' */
static inline u8 add_2reg(u8 byte, u32 a_reg, u32 x_reg)
{
return byte + reg2hex[a_reg] + (reg2hex[x_reg] << 3);
}
struct jit_context {
unsigned int cleanup_addr; /* epilogue code offset */
bool seen_ld_abs;
};
static int do_jit(struct sk_filter *bpf_prog, int *addrs, u8 *image,
int oldproglen, struct jit_context *ctx)
{
struct sock_filter_int *insn = bpf_prog->insnsi;
int insn_cnt = bpf_prog->len;
u8 temp[64];
int i;
int proglen = 0;
u8 *prog = temp;
int stacksize = MAX_BPF_STACK +
32 /* space for rbx, r13, r14, r15 */ +
8 /* space for skb_copy_bits() buffer */;
EMIT1(0x55); /* push rbp */
EMIT3(0x48, 0x89, 0xE5); /* mov rbp,rsp */
/* sub rsp, stacksize */
EMIT3_off32(0x48, 0x81, 0xEC, stacksize);
/* all classic BPF filters use R6(rbx) save it */
/* mov qword ptr [rbp-X],rbx */
EMIT3_off32(0x48, 0x89, 0x9D, -stacksize);
/* sk_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
* R8(r14). R9(r15) spill could be made conditional, but there is only
* one 'bpf_error' return path out of helper functions inside bpf_jit.S
* The overhead of extra spill is negligible for any filter other
* than synthetic ones. Therefore not worth adding complexity.
*/
for (proglen = 0, i = 0; i < flen; i++) {
proglen += 64;
addrs[i] = proglen;
}
cleanup_addr = proglen; /* epilogue address */
for (pass = 0; pass < 10; pass++) {
u8 seen_or_pass0 = (pass == 0) ? (SEEN_XREG | SEEN_DATAREF | SEEN_MEM) : seen;
/* no prologue/epilogue for trivial filters (RET something) */
proglen = 0;
prog = temp;
/* 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);
/* clear A and X registers */
EMIT2(0x31, 0xc0); /* xor eax, eax */
EMIT3(0x4D, 0x31, 0xED); /* xor r13, r13 */
if (seen_or_pass0) {
EMIT4(0x55, 0x48, 0x89, 0xe5); /* push %rbp; mov %rsp,%rbp */
EMIT4(0x48, 0x83, 0xec, 96); /* subq $96,%rsp */
/* note : must save %rbx in case bpf_error is hit */
if (seen_or_pass0 & (SEEN_XREG | SEEN_DATAREF))
EMIT4(0x48, 0x89, 0x5d, 0xf8); /* mov %rbx, -8(%rbp) */
if (seen_or_pass0 & SEEN_XREG)
CLEAR_X(); /* make sure we dont leek kernel memory */
/*
* If this filter needs to access skb data,
* loads r9 and r8 with :
* r9 = skb->len - skb->data_len
* r8 = skb->data
if (ctx->seen_ld_abs) {
/* r9d : skb->len - skb->data_len (headlen)
* r10 : skb->data
*/
if (seen_or_pass0 & SEEN_DATAREF) {
if (offsetof(struct sk_buff, len) <= 127)
/* mov off8(%rdi),%r9d */
EMIT4(0x44, 0x8b, 0x4f, offsetof(struct sk_buff, len));
else {
/* mov off32(%rdi),%r9d */
EMIT3(0x44, 0x8b, 0x8f);
EMIT(offsetof(struct sk_buff, len), 4);
}
if (is_imm8(offsetof(struct sk_buff, len)))
/* mov %r9d, off8(%rdi) */
EMIT4(0x44, 0x8b, 0x4f,
offsetof(struct sk_buff, len));
else
/* mov %r9d, off32(%rdi) */
EMIT3_off32(0x44, 0x8b, 0x8f,
offsetof(struct sk_buff, len));
if (is_imm8(offsetof(struct sk_buff, data_len)))
/* sub off8(%rdi),%r9d */
EMIT4(0x44, 0x2b, 0x4f, offsetof(struct sk_buff, data_len));
else {
EMIT3(0x44, 0x2b, 0x8f);
EMIT(offsetof(struct sk_buff, data_len), 4);
}
/* sub %r9d, off8(%rdi) */
EMIT4(0x44, 0x2b, 0x4f,
offsetof(struct sk_buff, data_len));
else
EMIT3_off32(0x44, 0x2b, 0x8f,
offsetof(struct sk_buff, data_len));
if (is_imm8(offsetof(struct sk_buff, data)))
/* mov off8(%rdi),%r8 */
EMIT4(0x4c, 0x8b, 0x47, offsetof(struct sk_buff, data));
else {
/* mov off32(%rdi),%r8 */
EMIT3(0x4c, 0x8b, 0x87);
EMIT(offsetof(struct sk_buff, data), 4);
}
}
}
/* mov %r10, off8(%rdi) */
EMIT4(0x4c, 0x8b, 0x57,
offsetof(struct sk_buff, data));
else
/* mov %r10, off32(%rdi) */
EMIT3_off32(0x4c, 0x8b, 0x97,
offsetof(struct sk_buff, data));
}
for (i = 0; i < insn_cnt; i++, insn++) {
const s32 K = insn->imm;
u32 a_reg = insn->a_reg;
u32 x_reg = insn->x_reg;
u8 b1 = 0, b2 = 0, b3 = 0;
s64 jmp_offset;
u8 jmp_cond;
int ilen;
u8 *func;
switch (filter[0].code) {
case BPF_S_RET_K:
case BPF_S_LD_W_LEN:
case BPF_S_ANC_PROTOCOL:
case BPF_S_ANC_IFINDEX:
case BPF_S_ANC_MARK:
case BPF_S_ANC_RXHASH:
case BPF_S_ANC_CPU:
case BPF_S_ANC_VLAN_TAG:
case BPF_S_ANC_VLAN_TAG_PRESENT:
case BPF_S_ANC_QUEUE:
case BPF_S_ANC_PKTTYPE:
case BPF_S_LD_W_ABS:
case BPF_S_LD_H_ABS:
case BPF_S_LD_B_ABS:
/* first instruction sets A register (or is RET 'constant') */
break;
default:
/* make sure we dont leak kernel information to user */
CLEAR_A(); /* A = 0 */
switch (insn->code) {
/* ALU */
case BPF_ALU | BPF_ADD | BPF_X:
case BPF_ALU | BPF_SUB | BPF_X:
case BPF_ALU | BPF_AND | BPF_X:
case BPF_ALU | BPF_OR | BPF_X:
case BPF_ALU | BPF_XOR | BPF_X:
case BPF_ALU64 | BPF_ADD | BPF_X:
case BPF_ALU64 | BPF_SUB | BPF_X:
case BPF_ALU64 | BPF_AND | BPF_X:
case BPF_ALU64 | BPF_OR | BPF_X:
case BPF_ALU64 | BPF_XOR | BPF_X:
switch (BPF_OP(insn->code)) {
case BPF_ADD: b2 = 0x01; break;
case BPF_SUB: b2 = 0x29; break;
case BPF_AND: b2 = 0x21; break;
case BPF_OR: b2 = 0x09; break;
case BPF_XOR: b2 = 0x31; break;
}
if (BPF_CLASS(insn->code) == BPF_ALU64)
EMIT1(add_2mod(0x48, a_reg, x_reg));
else if (is_ereg(a_reg) || is_ereg(x_reg))
EMIT1(add_2mod(0x40, a_reg, x_reg));
EMIT2(b2, add_2reg(0xC0, a_reg, x_reg));
break;
/* mov A, X */
case BPF_ALU64 | BPF_MOV | BPF_X:
EMIT_mov(a_reg, x_reg);
break;
/* mov32 A, X */
case BPF_ALU | BPF_MOV | BPF_X:
if (is_ereg(a_reg) || is_ereg(x_reg))
EMIT1(add_2mod(0x40, a_reg, x_reg));
EMIT2(0x89, add_2reg(0xC0, a_reg, x_reg));
break;
/* neg A */
case BPF_ALU | BPF_NEG:
case BPF_ALU64 | BPF_NEG:
if (BPF_CLASS(insn->code) == BPF_ALU64)
EMIT1(add_1mod(0x48, a_reg));
else if (is_ereg(a_reg))
EMIT1(add_1mod(0x40, a_reg));
EMIT2(0xF7, add_1reg(0xD8, a_reg));
break;
case BPF_ALU | BPF_ADD | BPF_K:
case BPF_ALU | BPF_SUB | BPF_K:
case BPF_ALU | BPF_AND | BPF_K:
case BPF_ALU | BPF_OR | BPF_K:
case BPF_ALU | BPF_XOR | BPF_K:
case BPF_ALU64 | BPF_ADD | BPF_K:
case BPF_ALU64 | BPF_SUB | BPF_K:
case BPF_ALU64 | BPF_AND | BPF_K:
case BPF_ALU64 | BPF_OR | BPF_K:
case BPF_ALU64 | BPF_XOR | BPF_K:
if (BPF_CLASS(insn->code) == BPF_ALU64)
EMIT1(add_1mod(0x48, a_reg));
else if (is_ereg(a_reg))
EMIT1(add_1mod(0x40, a_reg));
switch (BPF_OP(insn->code)) {
case BPF_ADD: b3 = 0xC0; break;
case BPF_SUB: b3 = 0xE8; break;
case BPF_AND: b3 = 0xE0; break;
case BPF_OR: b3 = 0xC8; break;
case BPF_XOR: b3 = 0xF0; break;
}
for (i = 0; i < flen; i++) {
unsigned int K = filter[i].k;
switch (filter[i].code) {
case BPF_S_ALU_ADD_X: /* A += X; */
seen |= SEEN_XREG;
EMIT2(0x01, 0xd8); /* add %ebx,%eax */
break;
case BPF_S_ALU_ADD_K: /* A += K; */
if (!K)
break;
if (is_imm8(K))
EMIT3(0x83, 0xc0, K); /* add imm8,%eax */
EMIT3(0x83, add_1reg(b3, a_reg), K);
else
EMIT1_off32(0x05, K); /* add imm32,%eax */
break;
case BPF_S_ALU_SUB_X: /* A -= X; */
seen |= SEEN_XREG;
EMIT2(0x29, 0xd8); /* sub %ebx,%eax */
EMIT2_off32(0x81, add_1reg(b3, a_reg), K);
break;
case BPF_S_ALU_SUB_K: /* A -= K */
if (!K)
break;
if (is_imm8(K))
EMIT3(0x83, 0xe8, K); /* sub imm8,%eax */
case BPF_ALU64 | BPF_MOV | BPF_K:
/* optimization: if imm32 is positive,
* use 'mov eax, imm32' (which zero-extends imm32)
* to save 2 bytes
*/
if (K < 0) {
/* 'mov rax, imm32' sign extends imm32 */
b1 = add_1mod(0x48, a_reg);
b2 = 0xC7;
b3 = 0xC0;
EMIT3_off32(b1, b2, add_1reg(b3, a_reg), K);
break;
}
case BPF_ALU | BPF_MOV | BPF_K:
/* mov %eax, imm32 */
if (is_ereg(a_reg))
EMIT1(add_1mod(0x40, a_reg));
EMIT1_off32(add_1reg(0xB8, a_reg), K);
break;
/* A %= X, A /= X, A %= K, A /= K */
case BPF_ALU | BPF_MOD | BPF_X:
case BPF_ALU | BPF_DIV | BPF_X:
case BPF_ALU | BPF_MOD | BPF_K:
case BPF_ALU | BPF_DIV | BPF_K:
case BPF_ALU64 | BPF_MOD | BPF_X:
case BPF_ALU64 | BPF_DIV | BPF_X:
case BPF_ALU64 | BPF_MOD | BPF_K:
case BPF_ALU64 | BPF_DIV | BPF_K:
EMIT1(0x50); /* push rax */
EMIT1(0x52); /* push rdx */
if (BPF_SRC(insn->code) == BPF_X)
/* mov r11, X */
EMIT_mov(AUX_REG, x_reg);
else
EMIT1_off32(0x2d, K); /* sub imm32,%eax */
break;
case BPF_S_ALU_MUL_X: /* A *= X; */
seen |= SEEN_XREG;
EMIT3(0x0f, 0xaf, 0xc3); /* imul %ebx,%eax */
break;
case BPF_S_ALU_MUL_K: /* A *= K */
if (is_imm8(K))
EMIT3(0x6b, 0xc0, K); /* imul imm8,%eax,%eax */
else {
EMIT2(0x69, 0xc0); /* imul imm32,%eax */
EMIT(K, 4);
}
break;
case BPF_S_ALU_DIV_X: /* A /= X; */
seen |= SEEN_XREG;
EMIT2(0x85, 0xdb); /* test %ebx,%ebx */
if (pc_ret0 > 0) {
/* addrs[pc_ret0 - 1] is start address of target
* (addrs[i] - 4) is the address following this jmp
* ("xor %edx,%edx; div %ebx" being 4 bytes long)
/* mov r11, K */
EMIT3_off32(0x49, 0xC7, 0xC3, K);
/* mov rax, A */
EMIT_mov(BPF_REG_0, a_reg);
/* xor edx, edx
* equivalent to 'xor rdx, rdx', but one byte less
*/
EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] -
(addrs[i] - 4));
} else {
EMIT_COND_JMP(X86_JNE, 2 + 5);
CLEAR_A();
EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 4)); /* jmp .+off32 */
}
EMIT4(0x31, 0xd2, 0xf7, 0xf3); /* xor %edx,%edx; div %ebx */
break;
case BPF_S_ALU_MOD_X: /* A %= X; */
seen |= SEEN_XREG;
EMIT2(0x85, 0xdb); /* test %ebx,%ebx */
if (pc_ret0 > 0) {
/* addrs[pc_ret0 - 1] is start address of target
* (addrs[i] - 6) is the address following this jmp
* ("xor %edx,%edx; div %ebx;mov %edx,%eax" being 6 bytes long)
EMIT2(0x31, 0xd2);
if (BPF_SRC(insn->code) == BPF_X) {
/* if (X == 0) return 0 */
/* cmp r11, 0 */
EMIT4(0x49, 0x83, 0xFB, 0x00);
/* jne .+9 (skip over pop, pop, xor and jmp) */
EMIT2(X86_JNE, 1 + 1 + 2 + 5);
EMIT1(0x5A); /* pop rdx */
EMIT1(0x58); /* pop rax */
EMIT2(0x31, 0xc0); /* xor eax, eax */
/* jmp cleanup_addr
* addrs[i] - 11, because there are 11 bytes
* after this insn: div, mov, pop, pop, mov
*/
EMIT_COND_JMP(X86_JE, addrs[pc_ret0 - 1] -
(addrs[i] - 6));
} else {
EMIT_COND_JMP(X86_JNE, 2 + 5);
CLEAR_A();
EMIT1_off32(0xe9, cleanup_addr - (addrs[i] - 6)); /* jmp .+off32 */
}
EMIT2(0x31, 0xd2); /* xor %edx,%edx */
EMIT2(0xf7, 0xf3); /* div %ebx */
EMIT2(0x89, 0xd0); /* mov %edx,%eax */
break;
case BPF_S_ALU_MOD_K: /* A %= K; */
if (K == 1) {
CLEAR_A();
break;
jmp_offset = ctx->cleanup_addr - (addrs[i] - 11);
EMIT1_off32(0xE9, jmp_offset);
}
EMIT2(0x31, 0xd2); /* xor %edx,%edx */
EMIT1(0xb9);EMIT(K, 4); /* mov imm32,%ecx */
EMIT2(0xf7, 0xf1); /* div %ecx */
EMIT2(0x89, 0xd0); /* mov %edx,%eax */
break;
case BPF_S_ALU_DIV_K: /* A /= K */
if (K == 1)
break;
EMIT2(0x31, 0xd2); /* xor %edx,%edx */
EMIT1(0xb9);EMIT(K, 4); /* mov imm32,%ecx */
EMIT2(0xf7, 0xf1); /* div %ecx */
break;
case BPF_S_ALU_AND_X:
seen |= SEEN_XREG;
EMIT2(0x21, 0xd8); /* and %ebx,%eax */
break;
case BPF_S_ALU_AND_K:
if (K >= 0xFFFFFF00) {
EMIT2(0x24, K & 0xFF); /* and imm8,%al */
} else if (K >= 0xFFFF0000) {
EMIT2(0x66, 0x25); /* and imm16,%ax */
EMIT(K, 2);
} else {
EMIT1_off32(0x25, K); /* and imm32,%eax */
}
break;
case BPF_S_ALU_OR_X:
seen |= SEEN_XREG;
EMIT2(0x09, 0xd8); /* or %ebx,%eax */
break;
case BPF_S_ALU_OR_K:
if (is_imm8(K))
EMIT3(0x83, 0xc8, K); /* or imm8,%eax */
if (BPF_CLASS(insn->code) == BPF_ALU64)
/* div r11 */
EMIT3(0x49, 0xF7, 0xF3);
else
EMIT1_off32(0x0d, K); /* or imm32,%eax */
break;
case BPF_S_ANC_ALU_XOR_X: /* A ^= X; */
case BPF_S_ALU_XOR_X:
seen |= SEEN_XREG;
EMIT2(0x31, 0xd8); /* xor %ebx,%eax */
break;
case BPF_S_ALU_XOR_K: /* A ^= K; */
if (K == 0)
break;
if (is_imm8(K))
EMIT3(0x83, 0xf0, K); /* xor imm8,%eax */
/* div r11d */
EMIT3(0x41, 0xF7, 0xF3);
if (BPF_OP(insn->code) == BPF_MOD)
/* mov r11, rdx */
EMIT3(0x49, 0x89, 0xD3);
else
EMIT1_off32(0x35, K); /* xor imm32,%eax */
break;
case BPF_S_ALU_LSH_X: /* A <<= X; */
seen |= SEEN_XREG;
EMIT4(0x89, 0xd9, 0xd3, 0xe0); /* mov %ebx,%ecx; shl %cl,%eax */
break;
case BPF_S_ALU_LSH_K:
if (K == 0)
/* mov r11, rax */
EMIT3(0x49, 0x89, 0xC3);
EMIT1(0x5A); /* pop rdx */
EMIT1(0x58); /* pop rax */
/* mov A, r11 */
EMIT_mov(a_reg, AUX_REG);
break;
else if (K == 1)
EMIT2(0xd1, 0xe0); /* shl %eax */
case BPF_ALU | BPF_MUL | BPF_K:
case BPF_ALU | BPF_MUL | BPF_X:
case BPF_ALU64 | BPF_MUL | BPF_K:
case BPF_ALU64 | BPF_MUL | BPF_X:
EMIT1(0x50); /* push rax */
EMIT1(0x52); /* push rdx */
/* mov r11, A */
EMIT_mov(AUX_REG, a_reg);
if (BPF_SRC(insn->code) == BPF_X)
/* mov rax, X */
EMIT_mov(BPF_REG_0, x_reg);
else
EMIT3(0xc1, 0xe0, K);
break;
case BPF_S_ALU_RSH_X: /* A >>= X; */
seen |= SEEN_XREG;
EMIT4(0x89, 0xd9, 0xd3, 0xe8); /* mov %ebx,%ecx; shr %cl,%eax */
break;
case BPF_S_ALU_RSH_K: /* A >>= K; */
if (K == 0)
break;
else if (K == 1)
EMIT2(0xd1, 0xe8); /* shr %eax */
/* mov rax, K */
EMIT3_off32(0x48, 0xC7, 0xC0, K);
if (BPF_CLASS(insn->code) == BPF_ALU64)
EMIT1(add_1mod(0x48, AUX_REG));
else if (is_ereg(AUX_REG))
EMIT1(add_1mod(0x40, AUX_REG));
/* mul(q) r11 */
EMIT2(0xF7, add_1reg(0xE0, AUX_REG));
/* mov r11, rax */
EMIT_mov(AUX_REG, BPF_REG_0);
EMIT1(0x5A); /* pop rdx */
EMIT1(0x58); /* pop rax */
/* mov A, r11 */
EMIT_mov(a_reg, AUX_REG);
break;
/* shifts */
case BPF_ALU | BPF_LSH | BPF_K:
case BPF_ALU | BPF_RSH | BPF_K:
case BPF_ALU | BPF_ARSH | BPF_K:
case BPF_ALU64 | BPF_LSH | BPF_K:
case BPF_ALU64 | BPF_RSH | BPF_K:
case BPF_ALU64 | BPF_ARSH | BPF_K:
if (BPF_CLASS(insn->code) == BPF_ALU64)
EMIT1(add_1mod(0x48, a_reg));
else if (is_ereg(a_reg))
EMIT1(add_1mod(0x40, a_reg));
switch (BPF_OP(insn->code)) {
case BPF_LSH: b3 = 0xE0; break;
case BPF_RSH: b3 = 0xE8; break;
case BPF_ARSH: b3 = 0xF8; break;
}
EMIT3(0xC1, add_1reg(b3, a_reg), K);
break;
case BPF_ALU | BPF_END | BPF_FROM_BE:
switch (K) {
case 16:
/* emit 'ror %ax, 8' to swap lower 2 bytes */
EMIT1(0x66);
if (is_ereg(a_reg))
EMIT1(0x41);
EMIT3(0xC1, add_1reg(0xC8, a_reg), 8);
break;
case 32:
/* emit 'bswap eax' to swap lower 4 bytes */
if (is_ereg(a_reg))
EMIT2(0x41, 0x0F);
else
EMIT3(0xc1, 0xe8, K);
EMIT1(0x0F);
EMIT1(add_1reg(0xC8, a_reg));
break;
case BPF_S_ALU_NEG:
EMIT2(0xf7, 0xd8); /* neg %eax */
case 64:
/* emit 'bswap rax' to swap 8 bytes */
EMIT3(add_1mod(0x48, a_reg), 0x0F,
add_1reg(0xC8, a_reg));
break;
case BPF_S_RET_K:
if (!K) {
if (pc_ret0 == -1)
pc_ret0 = i;
CLEAR_A();
} else {
EMIT1_off32(0xb8, K); /* mov $imm32,%eax */
}
/* fallinto */
case BPF_S_RET_A:
if (seen_or_pass0) {
if (i != flen - 1) {
EMIT_JMP(cleanup_addr - addrs[i]);
break;
}
if (seen_or_pass0 & SEEN_XREG)
EMIT4(0x48, 0x8b, 0x5d, 0xf8); /* mov -8(%rbp),%rbx */
EMIT1(0xc9); /* leaveq */
}
EMIT1(0xc3); /* ret */
break;
case BPF_S_MISC_TAX: /* X = A */
seen |= SEEN_XREG;
EMIT2(0x89, 0xc3); /* mov %eax,%ebx */
break;
case BPF_S_MISC_TXA: /* A = X */
seen |= SEEN_XREG;
EMIT2(0x89, 0xd8); /* mov %ebx,%eax */
case BPF_ALU | BPF_END | BPF_FROM_LE:
break;
case BPF_S_LD_IMM: /* A = K */
if (!K)
CLEAR_A();
/* ST: *(u8*)(a_reg + off) = imm */
case BPF_ST | BPF_MEM | BPF_B:
if (is_ereg(a_reg))
EMIT2(0x41, 0xC6);
else
EMIT1_off32(0xb8, K); /* mov $imm32,%eax */
break;
case BPF_S_LDX_IMM: /* X = K */
seen |= SEEN_XREG;
if (!K)
CLEAR_X();
EMIT1(0xC6);
goto st;
case BPF_ST | BPF_MEM | BPF_H:
if (is_ereg(a_reg))
EMIT3(0x66, 0x41, 0xC7);
else
EMIT1_off32(0xbb, K); /* mov $imm32,%ebx */
EMIT2(0x66, 0xC7);
goto st;
case BPF_ST | BPF_MEM | BPF_W:
if (is_ereg(a_reg))
EMIT2(0x41, 0xC7);
else
EMIT1(0xC7);
goto st;
case BPF_ST | BPF_MEM | BPF_DW:
EMIT2(add_1mod(0x48, a_reg), 0xC7);
st: if (is_imm8(insn->off))
EMIT2(add_1reg(0x40, a_reg), insn->off);
else
EMIT1_off32(add_1reg(0x80, a_reg), insn->off);
EMIT(K, bpf_size_to_x86_bytes(BPF_SIZE(insn->code)));
break;
case BPF_S_LD_MEM: /* A = mem[K] : mov off8(%rbp),%eax */
seen |= SEEN_MEM;
EMIT3(0x8b, 0x45, 0xf0 - K*4);
/* STX: *(u8*)(a_reg + off) = x_reg */
case BPF_STX | BPF_MEM | BPF_B:
/* emit 'mov byte ptr [rax + off], al' */
if (is_ereg(a_reg) || is_ereg(x_reg) ||
/* have to add extra byte for x86 SIL, DIL regs */
x_reg == BPF_REG_1 || x_reg == BPF_REG_2)
EMIT2(add_2mod(0x40, a_reg, x_reg), 0x88);
else
EMIT1(0x88);
goto stx;
case BPF_STX | BPF_MEM | BPF_H:
if (is_ereg(a_reg) || is_ereg(x_reg))
EMIT3(0x66, add_2mod(0x40, a_reg, x_reg), 0x89);
else
EMIT2(0x66, 0x89);
goto stx;
case BPF_STX | BPF_MEM | BPF_W:
if (is_ereg(a_reg) || is_ereg(x_reg))
EMIT2(add_2mod(0x40, a_reg, x_reg), 0x89);
else
EMIT1(0x89);
goto stx;
case BPF_STX | BPF_MEM | BPF_DW:
EMIT2(add_2mod(0x48, a_reg, x_reg), 0x89);
stx: if (is_imm8(insn->off))
EMIT2(add_2reg(0x40, a_reg, x_reg), insn->off);
else
EMIT1_off32(add_2reg(0x80, a_reg, x_reg),
insn->off);
break;
/* LDX: a_reg = *(u8*)(x_reg + off) */
case BPF_LDX | BPF_MEM | BPF_B:
/* emit 'movzx rax, byte ptr [rax + off]' */
EMIT3(add_2mod(0x48, x_reg, a_reg), 0x0F, 0xB6);
goto ldx;
case BPF_LDX | BPF_MEM | BPF_H:
/* emit 'movzx rax, word ptr [rax + off]' */
EMIT3(add_2mod(0x48, x_reg, a_reg), 0x0F, 0xB7);
goto ldx;
case BPF_LDX | BPF_MEM | BPF_W:
/* emit 'mov eax, dword ptr [rax+0x14]' */
if (is_ereg(a_reg) || is_ereg(x_reg))
EMIT2(add_2mod(0x40, x_reg, a_reg), 0x8B);
else
EMIT1(0x8B);
goto ldx;
case BPF_LDX | BPF_MEM | BPF_DW:
/* emit 'mov rax, qword ptr [rax+0x14]' */
EMIT2(add_2mod(0x48, x_reg, a_reg), 0x8B);
ldx: /* if insn->off == 0 we can save one extra byte, but
* special case of x86 r13 which always needs an offset
* is not worth the hassle
*/
if (is_imm8(insn->off))
EMIT2(add_2reg(0x40, x_reg, a_reg), insn->off);
else
EMIT1_off32(add_2reg(0x80, x_reg, a_reg),
insn->off);
break;
case BPF_S_LDX_MEM: /* X = mem[K] : mov off8(%rbp),%ebx */
seen |= SEEN_XREG | SEEN_MEM;
EMIT3(0x8b, 0x5d, 0xf0 - K*4);
/* STX XADD: lock *(u32*)(a_reg + off) += x_reg */
case BPF_STX | BPF_XADD | BPF_W:
/* emit 'lock add dword ptr [rax + off], eax' */
if (is_ereg(a_reg) || is_ereg(x_reg))
EMIT3(0xF0, add_2mod(0x40, a_reg, x_reg), 0x01);
else
EMIT2(0xF0, 0x01);
goto xadd;
case BPF_STX | BPF_XADD | BPF_DW:
EMIT3(0xF0, add_2mod(0x48, a_reg, x_reg), 0x01);
xadd: if (is_imm8(insn->off))
EMIT2(add_2reg(0x40, a_reg, x_reg), insn->off);
else
EMIT1_off32(add_2reg(0x80, a_reg, x_reg),
insn->off);
break;
/* call */
case BPF_JMP | BPF_CALL:
func = (u8 *) __bpf_call_base + K;
jmp_offset = func - (image + addrs[i]);
if (ctx->seen_ld_abs) {
EMIT2(0x41, 0x52); /* push %r10 */
EMIT2(0x41, 0x51); /* push %r9 */
/* need to adjust jmp offset, since
* pop %r9, pop %r10 take 4 bytes after call insn
*/
jmp_offset += 4;
}
if (!K || !is_simm32(jmp_offset)) {
pr_err("unsupported bpf func %d addr %p image %p\n",
K, func, image);
return -EINVAL;
}
EMIT1_off32(0xE8, jmp_offset);
if (ctx->seen_ld_abs) {
EMIT2(0x41, 0x59); /* pop %r9 */
EMIT2(0x41, 0x5A); /* pop %r10 */
}
break;
/* cond jump */
case BPF_JMP | BPF_JEQ | BPF_X:
case BPF_JMP | BPF_JNE | BPF_X:
case BPF_JMP | BPF_JGT | BPF_X:
case BPF_JMP | BPF_JGE | BPF_X:
case BPF_JMP | BPF_JSGT | BPF_X:
case BPF_JMP | BPF_JSGE | BPF_X:
/* cmp a_reg, x_reg */
EMIT3(add_2mod(0x48, a_reg, x_reg), 0x39,
add_2reg(0xC0, a_reg, x_reg));
goto emit_cond_jmp;
case BPF_JMP | BPF_JSET | BPF_X:
/* test a_reg, x_reg */
EMIT3(add_2mod(0x48, a_reg, x_reg), 0x85,
add_2reg(0xC0, a_reg, x_reg));
goto emit_cond_jmp;
case BPF_JMP | BPF_JSET | BPF_K:
/* test a_reg, imm32 */
EMIT1(add_1mod(0x48, a_reg));
EMIT2_off32(0xF7, add_1reg(0xC0, a_reg), K);
goto emit_cond_jmp;
case BPF_JMP | BPF_JEQ | BPF_K:
case BPF_JMP | BPF_JNE | BPF_K:
case BPF_JMP | BPF_JGT | BPF_K:
case BPF_JMP | BPF_JGE | BPF_K:
case BPF_JMP | BPF_JSGT | BPF_K:
case BPF_JMP | BPF_JSGE | BPF_K:
/* cmp a_reg, imm8/32 */
EMIT1(add_1mod(0x48, a_reg));
if (is_imm8(K))
EMIT3(0x83, add_1reg(0xF8, a_reg), K);
else
EMIT2_off32(0x81, add_1reg(0xF8, a_reg), K);
emit_cond_jmp: /* convert BPF opcode to x86 */
switch (BPF_OP(insn->code)) {
case BPF_JEQ:
jmp_cond = X86_JE;
break;
case BPF_S_ST: /* mem[K] = A : mov %eax,off8(%rbp) */
seen |= SEEN_MEM;
EMIT3(0x89, 0x45, 0xf0 - K*4);
case BPF_JSET:
case BPF_JNE:
jmp_cond = X86_JNE;
break;
case BPF_S_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
seen |= SEEN_XREG | SEEN_MEM;
EMIT3(0x89, 0x5d, 0xf0 - K*4);
case BPF_JGT:
/* GT is unsigned '>', JA in x86 */
jmp_cond = X86_JA;
break;
case BPF_S_LD_W_LEN: /* A = skb->len; */
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
if (is_imm8(offsetof(struct sk_buff, len)))
/* mov off8(%rdi),%eax */
EMIT3(0x8b, 0x47, offsetof(struct sk_buff, len));
else {
EMIT2(0x8b, 0x87);
EMIT(offsetof(struct sk_buff, len), 4);
}
case BPF_JGE:
/* GE is unsigned '>=', JAE in x86 */
jmp_cond = X86_JAE;
break;
case BPF_S_LDX_W_LEN: /* X = skb->len; */
seen |= SEEN_XREG;
if (is_imm8(offsetof(struct sk_buff, len)))
/* mov off8(%rdi),%ebx */
EMIT3(0x8b, 0x5f, offsetof(struct sk_buff, len));
else {
EMIT2(0x8b, 0x9f);
EMIT(offsetof(struct sk_buff, len), 4);
}
case BPF_JSGT:
/* signed '>', GT in x86 */
jmp_cond = X86_JG;
break;
case BPF_S_ANC_PROTOCOL: /* A = ntohs(skb->protocol); */
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
if (is_imm8(offsetof(struct sk_buff, protocol))) {
/* movzwl off8(%rdi),%eax */
EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, protocol));
} else {
EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
EMIT(offsetof(struct sk_buff, protocol), 4);
}
EMIT2(0x86, 0xc4); /* ntohs() : xchg %al,%ah */
case BPF_JSGE:
/* signed '>=', GE in x86 */
jmp_cond = X86_JGE;
break;
case BPF_S_ANC_IFINDEX:
if (is_imm8(offsetof(struct sk_buff, dev))) {
/* movq off8(%rdi),%rax */
EMIT4(0x48, 0x8b, 0x47, offsetof(struct sk_buff, dev));
} else {
EMIT3(0x48, 0x8b, 0x87); /* movq off32(%rdi),%rax */
EMIT(offsetof(struct sk_buff, dev), 4);
default: /* to silence gcc warning */
return -EFAULT;
}
EMIT3(0x48, 0x85, 0xc0); /* test %rax,%rax */
EMIT_COND_JMP(X86_JE, cleanup_addr - (addrs[i] - 6));
BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
EMIT2(0x8b, 0x80); /* mov off32(%rax),%eax */
EMIT(offsetof(struct net_device, ifindex), 4);
break;
case BPF_S_ANC_MARK:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
if (is_imm8(offsetof(struct sk_buff, mark))) {
/* mov off8(%rdi),%eax */
EMIT3(0x8b, 0x47, offsetof(struct sk_buff, mark));
jmp_offset = addrs[i + insn->off] - addrs[i];
if (is_imm8(jmp_offset)) {
EMIT2(jmp_cond, jmp_offset);
} else if (is_simm32(jmp_offset)) {
EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset);
} else {
EMIT2(0x8b, 0x87);
EMIT(offsetof(struct sk_buff, mark), 4);
pr_err("cond_jmp gen bug %llx\n", jmp_offset);
return -EFAULT;
}
break;
case BPF_S_ANC_RXHASH:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
if (is_imm8(offsetof(struct sk_buff, hash))) {
/* mov off8(%rdi),%eax */
EMIT3(0x8b, 0x47, offsetof(struct sk_buff, hash));
} else {
EMIT2(0x8b, 0x87);
EMIT(offsetof(struct sk_buff, hash), 4);
}
case BPF_JMP | BPF_JA:
jmp_offset = addrs[i + insn->off] - addrs[i];
if (!jmp_offset)
/* optimize out nop jumps */
break;
case BPF_S_ANC_QUEUE:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
if (is_imm8(offsetof(struct sk_buff, queue_mapping))) {
/* movzwl off8(%rdi),%eax */
EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, queue_mapping));
emit_jmp:
if (is_imm8(jmp_offset)) {
EMIT2(0xEB, jmp_offset);
} else if (is_simm32(jmp_offset)) {
EMIT1_off32(0xE9, jmp_offset);
} else {
EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
EMIT(offsetof(struct sk_buff, queue_mapping), 4);
pr_err("jmp gen bug %llx\n", jmp_offset);
return -EFAULT;
}
break;
case BPF_S_ANC_CPU:
#ifdef CONFIG_SMP
EMIT4(0x65, 0x8b, 0x04, 0x25); /* mov %gs:off32,%eax */
EMIT((u32)(unsigned long)&cpu_number, 4); /* A = smp_processor_id(); */
#else
CLEAR_A();
#endif
break;
case BPF_S_ANC_VLAN_TAG:
case BPF_S_ANC_VLAN_TAG_PRESENT:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
if (is_imm8(offsetof(struct sk_buff, vlan_tci))) {
/* movzwl off8(%rdi),%eax */
EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, vlan_tci));
} else {
EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
EMIT(offsetof(struct sk_buff, vlan_tci), 4);
}
BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
if (filter[i].code == BPF_S_ANC_VLAN_TAG) {
EMIT3(0x80, 0xe4, 0xef); /* and $0xef,%ah */
} else {
EMIT3(0xc1, 0xe8, 0x0c); /* shr $0xc,%eax */
EMIT3(0x83, 0xe0, 0x01); /* and $0x1,%eax */
}
break;
case BPF_S_ANC_PKTTYPE:
{
int off = pkt_type_offset();
if (off < 0)
goto out;
if (is_imm8(off)) {
/* movzbl off8(%rdi),%eax */
EMIT4(0x0f, 0xb6, 0x47, off);
case BPF_LD | BPF_IND | BPF_W:
func = sk_load_word;
goto common_load;
case BPF_LD | BPF_ABS | BPF_W:
func = CHOOSE_LOAD_FUNC(K, sk_load_word);
common_load: ctx->seen_ld_abs = true;
jmp_offset = func - (image + addrs[i]);
if (!func || !is_simm32(jmp_offset)) {
pr_err("unsupported bpf func %d addr %p image %p\n",
K, func, image);
return -EINVAL;
}
if (BPF_MODE(insn->code) == BPF_ABS) {
/* mov %esi, imm32 */
EMIT1_off32(0xBE, K);
} else {
/* movbl off32(%rdi),%eax */
EMIT3(0x0f, 0xb6, 0x87);
EMIT(off, 4);
/* mov %rsi, x_reg */
EMIT_mov(BPF_REG_2, x_reg);
if (K) {
if (is_imm8(K))
/* add %esi, imm8 */
EMIT3(0x83, 0xC6, K);
else
/* add %esi, imm32 */
EMIT2_off32(0x81, 0xC6, K);
}
EMIT3(0x83, 0xe0, PKT_TYPE_MAX); /* and $0x7,%eax */
break;
}
case BPF_S_LD_W_ABS:
func = CHOOSE_LOAD_FUNC(K, sk_load_word);
common_load: seen |= SEEN_DATAREF;
t_offset = func - (image + addrs[i]);
EMIT1_off32(0xbe, K); /* mov imm32,%esi */
EMIT1_off32(0xe8, t_offset); /* call */
/* skb pointer is in R6 (%rbx), it will be copied into
* %rdi if skb_copy_bits() call is necessary.
* sk_load_* helpers also use %r10 and %r9d.
* See bpf_jit.S
*/
EMIT1_off32(0xE8, jmp_offset); /* call */
break;
case BPF_S_LD_H_ABS:
case BPF_LD | BPF_IND | BPF_H:
func = sk_load_half;
goto common_load;
case BPF_LD | BPF_ABS | BPF_H:
func = CHOOSE_LOAD_FUNC(K, sk_load_half);
goto common_load;
case BPF_S_LD_B_ABS:
case BPF_LD | BPF_IND | BPF_B:
func = sk_load_byte;
goto common_load;
case BPF_LD | BPF_ABS | BPF_B:
func = CHOOSE_LOAD_FUNC(K, sk_load_byte);
goto common_load;
case BPF_S_LDX_B_MSH:
func = CHOOSE_LOAD_FUNC(K, sk_load_byte_msh);
seen |= SEEN_DATAREF | SEEN_XREG;
t_offset = func - (image + addrs[i]);
EMIT1_off32(0xbe, K); /* mov imm32,%esi */
EMIT1_off32(0xe8, t_offset); /* call sk_load_byte_msh */
break;
case BPF_S_LD_W_IND:
func = sk_load_word;
common_load_ind: seen |= SEEN_DATAREF | SEEN_XREG;
t_offset = func - (image + addrs[i]);
if (K) {
if (is_imm8(K)) {
EMIT3(0x8d, 0x73, K); /* lea imm8(%rbx), %esi */
} else {
EMIT2(0x8d, 0xb3); /* lea imm32(%rbx),%esi */
EMIT(K, 4);
}
} else {
EMIT2(0x89,0xde); /* mov %ebx,%esi */
}
EMIT1_off32(0xe8, t_offset); /* call sk_load_xxx_ind */
break;
case BPF_S_LD_H_IND:
func = sk_load_half;
goto common_load_ind;
case BPF_S_LD_B_IND:
func = sk_load_byte;
goto common_load_ind;
case BPF_S_JMP_JA:
t_offset = addrs[i + K] - addrs[i];
EMIT_JMP(t_offset);
break;
COND_SEL(BPF_S_JMP_JGT_K, X86_JA, X86_JBE);
COND_SEL(BPF_S_JMP_JGE_K, X86_JAE, X86_JB);
COND_SEL(BPF_S_JMP_JEQ_K, X86_JE, X86_JNE);
COND_SEL(BPF_S_JMP_JSET_K,X86_JNE, X86_JE);
COND_SEL(BPF_S_JMP_JGT_X, X86_JA, X86_JBE);
COND_SEL(BPF_S_JMP_JGE_X, X86_JAE, X86_JB);
COND_SEL(BPF_S_JMP_JEQ_X, X86_JE, X86_JNE);
COND_SEL(BPF_S_JMP_JSET_X,X86_JNE, X86_JE);
cond_branch: f_offset = addrs[i + filter[i].jf] - addrs[i];
t_offset = addrs[i + filter[i].jt] - addrs[i];
/* same targets, can avoid doing the test :) */
if (filter[i].jt == filter[i].jf) {
EMIT_JMP(t_offset);
break;
}
switch (filter[i].code) {
case BPF_S_JMP_JGT_X:
case BPF_S_JMP_JGE_X:
case BPF_S_JMP_JEQ_X:
seen |= SEEN_XREG;
EMIT2(0x39, 0xd8); /* cmp %ebx,%eax */
break;
case BPF_S_JMP_JSET_X:
seen |= SEEN_XREG;
EMIT2(0x85, 0xd8); /* test %ebx,%eax */
break;
case BPF_S_JMP_JEQ_K:
if (K == 0) {
EMIT2(0x85, 0xc0); /* test %eax,%eax */
break;
}
case BPF_S_JMP_JGT_K:
case BPF_S_JMP_JGE_K:
if (K <= 127)
EMIT3(0x83, 0xf8, K); /* cmp imm8,%eax */
else
EMIT1_off32(0x3d, K); /* cmp imm32,%eax */
break;
case BPF_S_JMP_JSET_K:
if (K <= 0xFF)
EMIT2(0xa8, K); /* test imm8,%al */
else if (!(K & 0xFFFF00FF))
EMIT3(0xf6, 0xc4, K >> 8); /* test imm8,%ah */
else if (K <= 0xFFFF) {
EMIT2(0x66, 0xa9); /* test imm16,%ax */
EMIT(K, 2);
} else {
EMIT1_off32(0xa9, K); /* test imm32,%eax */
}
break;
case BPF_JMP | BPF_EXIT:
if (i != insn_cnt - 1) {
jmp_offset = ctx->cleanup_addr - addrs[i];
goto emit_jmp;
}
if (filter[i].jt != 0) {
if (filter[i].jf && f_offset)
t_offset += is_near(f_offset) ? 2 : 5;
EMIT_COND_JMP(t_op, t_offset);
if (filter[i].jf)
EMIT_JMP(f_offset);
break;
}
EMIT_COND_JMP(f_op, f_offset);
/* 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);
EMIT1(0xC9); /* leave */
EMIT1(0xC3); /* ret */
break;
default:
/* hmm, too complex filter, give up with jit compiler */
goto out;
/* By design x64 JIT should support all BPF instructions
* This error will be seen if new instruction was added
* to interpreter, but not to JIT
* or if there is junk in sk_filter
*/
pr_err("bpf_jit: unknown opcode %02x\n", insn->code);
return -EINVAL;
}
ilen = prog - temp;
if (image) {
if (unlikely(proglen + ilen > oldproglen)) {
pr_err("bpb_jit_compile fatal error\n");
kfree(addrs);
module_free(NULL, header);
return;
pr_err("bpf_jit_compile fatal error\n");
return -EFAULT;
}
memcpy(image + proglen, temp, ilen);
}
......@@ -743,18 +859,54 @@ cond_branch: f_offset = addrs[i + filter[i].jf] - addrs[i];
addrs[i] = proglen;
prog = temp;
}
/* last bpf instruction is always a RET :
* use it to give the cleanup instruction(s) addr
return proglen;
}
void bpf_jit_compile(struct sk_filter *prog)
{
}
void bpf_int_jit_compile(struct sk_filter *prog)
{
struct bpf_binary_header *header = NULL;
int proglen, oldproglen = 0;
struct jit_context ctx = {};
u8 *image = NULL;
int *addrs;
int pass;
int i;
if (!bpf_jit_enable)
return;
if (!prog || !prog->len)
return;
addrs = kmalloc(prog->len * sizeof(*addrs), GFP_KERNEL);
if (!addrs)
return;
/* Before first pass, make a rough estimation of addrs[]
* each bpf instruction is translated to less than 64 bytes
*/
cleanup_addr = proglen - 1; /* ret */
if (seen_or_pass0)
cleanup_addr -= 1; /* leaveq */
if (seen_or_pass0 & SEEN_XREG)
cleanup_addr -= 4; /* mov -8(%rbp),%rbx */
for (proglen = 0, i = 0; i < prog->len; i++) {
proglen += 64;
addrs[i] = proglen;
}
ctx.cleanup_addr = proglen;
for (pass = 0; pass < 10; pass++) {
proglen = do_jit(prog, addrs, image, oldproglen, &ctx);
if (proglen <= 0) {
image = NULL;
if (header)
module_free(NULL, header);
goto out;
}
if (image) {
if (proglen != oldproglen)
pr_err("bpb_jit_compile proglen=%u != oldproglen=%u\n", proglen, oldproglen);
pr_err("bpf_jit: proglen=%d != oldproglen=%d\n",
proglen, oldproglen);
break;
}
if (proglen == oldproglen) {
......@@ -766,17 +918,16 @@ cond_branch: f_offset = addrs[i + filter[i].jf] - addrs[i];
}
if (bpf_jit_enable > 1)
bpf_jit_dump(flen, proglen, pass, image);
bpf_jit_dump(prog->len, proglen, 0, image);
if (image) {
bpf_flush_icache(header, image + proglen);
set_memory_ro((unsigned long)header, header->pages);
fp->bpf_func = (void *)image;
fp->jited = 1;
prog->bpf_func = (void *)image;
prog->jited = 1;
}
out:
kfree(addrs);
return;
}
static void bpf_jit_free_deferred(struct work_struct *work)
......
include/linux/filter.h
View file @ 1f499d6a
......@@ -207,6 +207,9 @@ void sk_decode_filter(struct sock_filter *filt, struct sock_filter *to);
void sk_filter_charge(struct sock *sk, struct sk_filter *fp);
void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
void bpf_int_jit_compile(struct sk_filter *fp);
#ifdef CONFIG_BPF_JIT
#include <stdarg.h>
#include <linux/linkage.h>
......
kernel/seccomp.c
View file @ 1f499d6a
......@@ -54,8 +54,7 @@
struct seccomp_filter {
atomic_t usage;
struct seccomp_filter *prev;
unsigned short len; /* Instruction count */
struct sock_filter_int insnsi[];
struct sk_filter *prog;
};
/* Limit any path through the tree to 256KB worth of instructions. */
......@@ -189,7 +188,8 @@ static u32 seccomp_run_filters(int syscall)
* value always takes priority (ignoring the DATA).
*/
for (f = current->seccomp.filter; f; f = f->prev) {
u32 cur_ret = sk_run_filter_int_seccomp(&sd, f->insnsi);
u32 cur_ret = SK_RUN_FILTER(f->prog, (void *)&sd);
if ((cur_ret & SECCOMP_RET_ACTION) < (ret & SECCOMP_RET_ACTION))
ret = cur_ret;
}
......@@ -215,7 +215,7 @@ static long seccomp_attach_filter(struct sock_fprog *fprog)
return -EINVAL;
for (filter = current->seccomp.filter; filter; filter = filter->prev)
total_insns += filter->len + 4; /* include a 4 instr penalty */
total_insns += filter->prog->len + 4; /* include a 4 instr penalty */
if (total_insns > MAX_INSNS_PER_PATH)
return -ENOMEM;
......@@ -256,19 +256,27 @@ static long seccomp_attach_filter(struct sock_fprog *fprog)
/* Allocate a new seccomp_filter */
ret = -ENOMEM;
filter = kzalloc(sizeof(struct seccomp_filter) +
sizeof(struct sock_filter_int) * new_len,
filter = kzalloc(sizeof(struct seccomp_filter),
GFP_KERNEL|__GFP_NOWARN);
if (!filter)
goto free_prog;
ret = sk_convert_filter(fp, fprog->len, filter->insnsi, &new_len);
if (ret)
filter->prog = kzalloc(sk_filter_size(new_len),
GFP_KERNEL|__GFP_NOWARN);
if (!filter->prog)
goto free_filter;
ret = sk_convert_filter(fp, fprog->len, filter->prog->insnsi, &new_len);
if (ret)
goto free_filter_prog;
kfree(fp);
atomic_set(&filter->usage, 1);
filter->len = new_len;
filter->prog->len = new_len;
filter->prog->bpf_func = (void *)sk_run_filter_int_seccomp;
/* JIT internal BPF into native HW instructions */
bpf_int_jit_compile(filter->prog);
/*
* If there is an existing filter, make it the prev and don't drop its
......@@ -278,6 +286,8 @@ static long seccomp_attach_filter(struct sock_fprog *fprog)
current->seccomp.filter = filter;
return 0;
free_filter_prog:
kfree(filter->prog);
free_filter:
kfree(filter);
free_prog:
......@@ -330,6 +340,7 @@ void put_seccomp_filter(struct task_struct *tsk)
while (orig && atomic_dec_and_test(&orig->usage)) {
struct seccomp_filter *freeme = orig;
orig = orig->prev;
bpf_jit_free(freeme->prog);
kfree(freeme);
}
}
......
net/core/filter.c
View file @ 1f499d6a
......@@ -1524,6 +1524,10 @@ static struct sk_filter *__sk_migrate_filter(struct sk_filter *fp,
return ERR_PTR(err);
}
void __weak bpf_int_jit_compile(struct sk_filter *prog)
{
}
static struct sk_filter *__sk_prepare_filter(struct sk_filter *fp,
struct sock *sk)
{
......@@ -1544,9 +1548,12 @@ static struct sk_filter *__sk_prepare_filter(struct sk_filter *fp,
/* JIT compiler couldn't process this filter, so do the
* internal BPF translation for the optimized interpreter.
*/
if (!fp->jited)
if (!fp->jited) {
fp = __sk_migrate_filter(fp, sk);
/* Probe if internal BPF can be jit-ed */
bpf_int_jit_compile(fp);
}
return fp;
}
......
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