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linux/arch/s390/net/bpf_jit_comp.c
Daniel Borkmann 738cbe72ad net: bpf: consolidate JIT binary allocator 
Introduced in commit 314beb9bca ("x86: bpf_jit_comp: secure bpf jit
against spraying attacks") and later on replicated in aa2d2c73c2
("s390/bpf,jit: address randomize and write protect jit code") for
s390 architecture, write protection for BPF JIT images got added and
a random start address of the JIT code, so that it's not on a page
boundary anymore.

Since both use a very similar allocator for the BPF binary header,
we can consolidate this code into the BPF core as it's mostly JIT
independant anyway.

This will also allow for future archs that support DEBUG_SET_MODULE_RONX
to just reuse instead of reimplementing it.

JIT tested on x86_64 and s390x with BPF test suite.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-09 16:58:56 -07:00

865 lines
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C
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/*
* BPF Jit compiler for s390.
*
* Copyright IBM Corp. 2012
*
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
#include <linux/netdevice.h>
#include <linux/if_vlan.h>
#include <linux/filter.h>
#include <linux/init.h>
#include <asm/cacheflush.h>
#include <asm/facility.h>
#include <asm/dis.h>
/*
* Conventions:
* %r2 = skb pointer
* %r3 = offset parameter
* %r4 = scratch register / length parameter
* %r5 = BPF A accumulator
* %r8 = return address
* %r9 = save register for skb pointer
* %r10 = skb->data
* %r11 = skb->len - skb->data_len (headlen)
* %r12 = BPF X accumulator
* %r13 = literal pool pointer
* 0(%r15) - 63(%r15) scratch memory array with BPF_MEMWORDS
*/
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_ind[], sk_load_half_ind[], sk_load_byte_ind[];
struct bpf_jit {
unsigned int seen;
u8 *start;
u8 *prg;
u8 *mid;
u8 *lit;
u8 *end;
u8 *base_ip;
u8 *ret0_ip;
u8 *exit_ip;
unsigned int off_load_word;
unsigned int off_load_half;
unsigned int off_load_byte;
unsigned int off_load_bmsh;
unsigned int off_load_iword;
unsigned int off_load_ihalf;
unsigned int off_load_ibyte;
};
#define BPF_SIZE_MAX 4096 /* Max size for program */
#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 SEEN_RET0 8 /* pc_ret0 points to a valid return 0 */
#define SEEN_LITERAL 16 /* code uses literals */
#define SEEN_LOAD_WORD 32 /* code uses sk_load_word */
#define SEEN_LOAD_HALF 64 /* code uses sk_load_half */
#define SEEN_LOAD_BYTE 128 /* code uses sk_load_byte */
#define SEEN_LOAD_BMSH 256 /* code uses sk_load_byte_msh */
#define SEEN_LOAD_IWORD 512 /* code uses sk_load_word_ind */
#define SEEN_LOAD_IHALF 1024 /* code uses sk_load_half_ind */
#define SEEN_LOAD_IBYTE 2048 /* code uses sk_load_byte_ind */
#define EMIT2(op) \
({ \
if (jit->prg + 2 <= jit->mid) \
*(u16 *) jit->prg = op; \
jit->prg += 2; \
})
#define EMIT4(op) \
({ \
if (jit->prg + 4 <= jit->mid) \
*(u32 *) jit->prg = op; \
jit->prg += 4; \
})
#define EMIT4_DISP(op, disp) \
({ \
unsigned int __disp = (disp) & 0xfff; \
EMIT4(op | __disp); \
})
#define EMIT4_IMM(op, imm) \
({ \
unsigned int __imm = (imm) & 0xffff; \
EMIT4(op | __imm); \
})
#define EMIT4_PCREL(op, pcrel) \
({ \
long __pcrel = ((pcrel) >> 1) & 0xffff; \
EMIT4(op | __pcrel); \
})
#define EMIT6(op1, op2) \
({ \
if (jit->prg + 6 <= jit->mid) { \
*(u32 *) jit->prg = op1; \
*(u16 *) (jit->prg + 4) = op2; \
} \
jit->prg += 6; \
})
#define EMIT6_DISP(op1, op2, disp) \
({ \
unsigned int __disp = (disp) & 0xfff; \
EMIT6(op1 | __disp, op2); \
})
#define EMIT6_IMM(op, imm) \
({ \
unsigned int __imm = (imm); \
EMIT6(op | (__imm >> 16), __imm & 0xffff); \
})
#define EMIT_CONST(val) \
({ \
unsigned int ret; \
ret = (unsigned int) (jit->lit - jit->base_ip); \
jit->seen |= SEEN_LITERAL; \
if (jit->lit + 4 <= jit->end) \
*(u32 *) jit->lit = val; \
jit->lit += 4; \
ret; \
})
#define EMIT_FN_CONST(bit, fn) \
({ \
unsigned int ret; \
ret = (unsigned int) (jit->lit - jit->base_ip); \
if (jit->seen & bit) { \
jit->seen |= SEEN_LITERAL; \
if (jit->lit + 8 <= jit->end) \
*(void **) jit->lit = fn; \
jit->lit += 8; \
} \
ret; \
})
static void bpf_jit_fill_hole(void *area, unsigned int size)
{
/* Fill whole space with illegal instructions */
memset(area, 0, size);
}
static void bpf_jit_prologue(struct bpf_jit *jit)
{
/* Save registers and create stack frame if necessary */
if (jit->seen & SEEN_DATAREF) {
/* stmg %r8,%r15,88(%r15) */
EMIT6(0xeb8ff058, 0x0024);
/* lgr %r14,%r15 */
EMIT4(0xb90400ef);
/* aghi %r15,<offset> */
EMIT4_IMM(0xa7fb0000, (jit->seen & SEEN_MEM) ? -112 : -80);
/* stg %r14,152(%r15) */
EMIT6(0xe3e0f098, 0x0024);
} else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
/* stmg %r12,%r13,120(%r15) */
EMIT6(0xebcdf078, 0x0024);
else if (jit->seen & SEEN_XREG)
/* stg %r12,120(%r15) */
EMIT6(0xe3c0f078, 0x0024);
else if (jit->seen & SEEN_LITERAL)
/* stg %r13,128(%r15) */
EMIT6(0xe3d0f080, 0x0024);
/* Setup literal pool */
if (jit->seen & SEEN_LITERAL) {
/* basr %r13,0 */
EMIT2(0x0dd0);
jit->base_ip = jit->prg;
}
jit->off_load_word = EMIT_FN_CONST(SEEN_LOAD_WORD, sk_load_word);
jit->off_load_half = EMIT_FN_CONST(SEEN_LOAD_HALF, sk_load_half);
jit->off_load_byte = EMIT_FN_CONST(SEEN_LOAD_BYTE, sk_load_byte);
jit->off_load_bmsh = EMIT_FN_CONST(SEEN_LOAD_BMSH, sk_load_byte_msh);
jit->off_load_iword = EMIT_FN_CONST(SEEN_LOAD_IWORD, sk_load_word_ind);
jit->off_load_ihalf = EMIT_FN_CONST(SEEN_LOAD_IHALF, sk_load_half_ind);
jit->off_load_ibyte = EMIT_FN_CONST(SEEN_LOAD_IBYTE, sk_load_byte_ind);
/* Filter needs to access skb data */
if (jit->seen & SEEN_DATAREF) {
/* l %r11,<len>(%r2) */
EMIT4_DISP(0x58b02000, offsetof(struct sk_buff, len));
/* s %r11,<data_len>(%r2) */
EMIT4_DISP(0x5bb02000, offsetof(struct sk_buff, data_len));
/* lg %r10,<data>(%r2) */
EMIT6_DISP(0xe3a02000, 0x0004,
offsetof(struct sk_buff, data));
}
}
static void bpf_jit_epilogue(struct bpf_jit *jit)
{
/* Return 0 */
if (jit->seen & SEEN_RET0) {
jit->ret0_ip = jit->prg;
/* lghi %r2,0 */
EMIT4(0xa7290000);
}
jit->exit_ip = jit->prg;
/* Restore registers */
if (jit->seen & SEEN_DATAREF)
/* lmg %r8,%r15,<offset>(%r15) */
EMIT6_DISP(0xeb8ff000, 0x0004,
(jit->seen & SEEN_MEM) ? 200 : 168);
else if ((jit->seen & SEEN_XREG) && (jit->seen & SEEN_LITERAL))
/* lmg %r12,%r13,120(%r15) */
EMIT6(0xebcdf078, 0x0004);
else if (jit->seen & SEEN_XREG)
/* lg %r12,120(%r15) */
EMIT6(0xe3c0f078, 0x0004);
else if (jit->seen & SEEN_LITERAL)
/* lg %r13,128(%r15) */
EMIT6(0xe3d0f080, 0x0004);
/* br %r14 */
EMIT2(0x07fe);
}
/* Helper to find the offset of pkt_type in sk_buff
* Make sure its still a 3bit field starting at the MSBs within a byte.
*/
#define PKT_TYPE_MAX 0xe0
static int pkt_type_offset;
static int __init bpf_pkt_type_offset_init(void)
{
struct sk_buff skb_probe = {
.pkt_type = ~0,
};
char *ct = (char *)&skb_probe;
int off;
pkt_type_offset = -1;
for (off = 0; off < sizeof(struct sk_buff); off++) {
if (!ct[off])
continue;
if (ct[off] == PKT_TYPE_MAX)
pkt_type_offset = off;
else {
/* Found non matching bit pattern, fix needed. */
WARN_ON_ONCE(1);
pkt_type_offset = -1;
return -1;
}
}
return 0;
}
device_initcall(bpf_pkt_type_offset_init);
/*
* make sure we dont leak kernel information to user
*/
static void bpf_jit_noleaks(struct bpf_jit *jit, struct sock_filter *filter)
{
/* Clear temporary memory if (seen & SEEN_MEM) */
if (jit->seen & SEEN_MEM)
/* xc 0(64,%r15),0(%r15) */
EMIT6(0xd73ff000, 0xf000);
/* Clear X if (seen & SEEN_XREG) */
if (jit->seen & SEEN_XREG)
/* lhi %r12,0 */
EMIT4(0xa7c80000);
/* Clear A if the first register does not set it. */
switch (filter[0].code) {
case BPF_LD | BPF_W | BPF_ABS:
case BPF_LD | BPF_H | BPF_ABS:
case BPF_LD | BPF_B | BPF_ABS:
case BPF_LD | BPF_W | BPF_LEN:
case BPF_LD | BPF_W | BPF_IND:
case BPF_LD | BPF_H | BPF_IND:
case BPF_LD | BPF_B | BPF_IND:
case BPF_LD | BPF_IMM:
case BPF_LD | BPF_MEM:
case BPF_MISC | BPF_TXA:
case BPF_RET | BPF_K:
/* first instruction sets A register */
break;
default: /* A = 0 */
/* lhi %r5,0 */
EMIT4(0xa7580000);
}
}
static int bpf_jit_insn(struct bpf_jit *jit, struct sock_filter *filter,
unsigned int *addrs, int i, int last)
{
unsigned int K;
int offset;
unsigned int mask;
u16 code;
K = filter->k;
code = bpf_anc_helper(filter);
switch (code) {
case BPF_ALU | BPF_ADD | BPF_X: /* A += X */
jit->seen |= SEEN_XREG;
/* ar %r5,%r12 */
EMIT2(0x1a5c);
break;
case BPF_ALU | BPF_ADD | BPF_K: /* A += K */
if (!K)
break;
if (K <= 16383)
/* ahi %r5,<K> */
EMIT4_IMM(0xa75a0000, K);
else if (test_facility(21))
/* alfi %r5,<K> */
EMIT6_IMM(0xc25b0000, K);
else
/* a %r5,<d(K)>(%r13) */
EMIT4_DISP(0x5a50d000, EMIT_CONST(K));
break;
case BPF_ALU | BPF_SUB | BPF_X: /* A -= X */
jit->seen |= SEEN_XREG;
/* sr %r5,%r12 */
EMIT2(0x1b5c);
break;
case BPF_ALU | BPF_SUB | BPF_K: /* A -= K */
if (!K)
break;
if (K <= 16384)
/* ahi %r5,-K */
EMIT4_IMM(0xa75a0000, -K);
else if (test_facility(21))
/* alfi %r5,-K */
EMIT6_IMM(0xc25b0000, -K);
else
/* s %r5,<d(K)>(%r13) */
EMIT4_DISP(0x5b50d000, EMIT_CONST(K));
break;
case BPF_ALU | BPF_MUL | BPF_X: /* A *= X */
jit->seen |= SEEN_XREG;
/* msr %r5,%r12 */
EMIT4(0xb252005c);
break;
case BPF_ALU | BPF_MUL | BPF_K: /* A *= K */
if (K <= 16383)
/* mhi %r5,K */
EMIT4_IMM(0xa75c0000, K);
else if (test_facility(34))
/* msfi %r5,<K> */
EMIT6_IMM(0xc2510000, K);
else
/* ms %r5,<d(K)>(%r13) */
EMIT4_DISP(0x7150d000, EMIT_CONST(K));
break;
case BPF_ALU | BPF_DIV | BPF_X: /* A /= X */
jit->seen |= SEEN_XREG | SEEN_RET0;
/* ltr %r12,%r12 */
EMIT2(0x12cc);
/* jz <ret0> */
EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
/* lhi %r4,0 */
EMIT4(0xa7480000);
/* dlr %r4,%r12 */
EMIT4(0xb997004c);
break;
case BPF_ALU | BPF_DIV | BPF_K: /* A /= K */
if (K == 1)
break;
/* lhi %r4,0 */
EMIT4(0xa7480000);
/* dl %r4,<d(K)>(%r13) */
EMIT6_DISP(0xe340d000, 0x0097, EMIT_CONST(K));
break;
case BPF_ALU | BPF_MOD | BPF_X: /* A %= X */
jit->seen |= SEEN_XREG | SEEN_RET0;
/* ltr %r12,%r12 */
EMIT2(0x12cc);
/* jz <ret0> */
EMIT4_PCREL(0xa7840000, (jit->ret0_ip - jit->prg));
/* lhi %r4,0 */
EMIT4(0xa7480000);
/* dlr %r4,%r12 */
EMIT4(0xb997004c);
/* lr %r5,%r4 */
EMIT2(0x1854);
break;
case BPF_ALU | BPF_MOD | BPF_K: /* A %= K */
if (K == 1) {
/* lhi %r5,0 */
EMIT4(0xa7580000);
break;
}
/* lhi %r4,0 */
EMIT4(0xa7480000);
/* dl %r4,<d(K)>(%r13) */
EMIT6_DISP(0xe340d000, 0x0097, EMIT_CONST(K));
/* lr %r5,%r4 */
EMIT2(0x1854);
break;
case BPF_ALU | BPF_AND | BPF_X: /* A &= X */
jit->seen |= SEEN_XREG;
/* nr %r5,%r12 */
EMIT2(0x145c);
break;
case BPF_ALU | BPF_AND | BPF_K: /* A &= K */
if (test_facility(21))
/* nilf %r5,<K> */
EMIT6_IMM(0xc05b0000, K);
else
/* n %r5,<d(K)>(%r13) */
EMIT4_DISP(0x5450d000, EMIT_CONST(K));
break;
case BPF_ALU | BPF_OR | BPF_X: /* A |= X */
jit->seen |= SEEN_XREG;
/* or %r5,%r12 */
EMIT2(0x165c);
break;
case BPF_ALU | BPF_OR | BPF_K: /* A |= K */
if (test_facility(21))
/* oilf %r5,<K> */
EMIT6_IMM(0xc05d0000, K);
else
/* o %r5,<d(K)>(%r13) */
EMIT4_DISP(0x5650d000, EMIT_CONST(K));
break;
case BPF_ANC | SKF_AD_ALU_XOR_X: /* A ^= X; */
case BPF_ALU | BPF_XOR | BPF_X:
jit->seen |= SEEN_XREG;
/* xr %r5,%r12 */
EMIT2(0x175c);
break;
case BPF_ALU | BPF_XOR | BPF_K: /* A ^= K */
if (!K)
break;
/* x %r5,<d(K)>(%r13) */
EMIT4_DISP(0x5750d000, EMIT_CONST(K));
break;
case BPF_ALU | BPF_LSH | BPF_X: /* A <<= X; */
jit->seen |= SEEN_XREG;
/* sll %r5,0(%r12) */
EMIT4(0x8950c000);
break;
case BPF_ALU | BPF_LSH | BPF_K: /* A <<= K */
if (K == 0)
break;
/* sll %r5,K */
EMIT4_DISP(0x89500000, K);
break;
case BPF_ALU | BPF_RSH | BPF_X: /* A >>= X; */
jit->seen |= SEEN_XREG;
/* srl %r5,0(%r12) */
EMIT4(0x8850c000);
break;
case BPF_ALU | BPF_RSH | BPF_K: /* A >>= K; */
if (K == 0)
break;
/* srl %r5,K */
EMIT4_DISP(0x88500000, K);
break;
case BPF_ALU | BPF_NEG: /* A = -A */
/* lnr %r5,%r5 */
EMIT2(0x1155);
break;
case BPF_JMP | BPF_JA: /* ip += K */
offset = addrs[i + K] + jit->start - jit->prg;
EMIT4_PCREL(0xa7f40000, offset);
break;
case BPF_JMP | BPF_JGT | BPF_K: /* ip += (A > K) ? jt : jf */
mask = 0x200000; /* jh */
goto kbranch;
case BPF_JMP | BPF_JGE | BPF_K: /* ip += (A >= K) ? jt : jf */
mask = 0xa00000; /* jhe */
goto kbranch;
case BPF_JMP | BPF_JEQ | BPF_K: /* ip += (A == K) ? jt : jf */
mask = 0x800000; /* je */
kbranch: /* Emit compare if the branch targets are different */
if (filter->jt != filter->jf) {
if (K <= 16383)
/* chi %r5,<K> */
EMIT4_IMM(0xa75e0000, K);
else if (test_facility(21))
/* clfi %r5,<K> */
EMIT6_IMM(0xc25f0000, K);
else
/* c %r5,<d(K)>(%r13) */
EMIT4_DISP(0x5950d000, EMIT_CONST(K));
}
branch: if (filter->jt == filter->jf) {
if (filter->jt == 0)
break;
/* j <jt> */
offset = addrs[i + filter->jt] + jit->start - jit->prg;
EMIT4_PCREL(0xa7f40000, offset);
break;
}
if (filter->jt != 0) {
/* brc <mask>,<jt> */
offset = addrs[i + filter->jt] + jit->start - jit->prg;
EMIT4_PCREL(0xa7040000 | mask, offset);
}
if (filter->jf != 0) {
/* brc <mask^15>,<jf> */
offset = addrs[i + filter->jf] + jit->start - jit->prg;
EMIT4_PCREL(0xa7040000 | (mask ^ 0xf00000), offset);
}
break;
case BPF_JMP | BPF_JSET | BPF_K: /* ip += (A & K) ? jt : jf */
mask = 0x700000; /* jnz */
/* Emit test if the branch targets are different */
if (filter->jt != filter->jf) {
if (K > 65535) {
/* lr %r4,%r5 */
EMIT2(0x1845);
/* n %r4,<d(K)>(%r13) */
EMIT4_DISP(0x5440d000, EMIT_CONST(K));
} else
/* tmll %r5,K */
EMIT4_IMM(0xa7510000, K);
}
goto branch;
case BPF_JMP | BPF_JGT | BPF_X: /* ip += (A > X) ? jt : jf */
mask = 0x200000; /* jh */
goto xbranch;
case BPF_JMP | BPF_JGE | BPF_X: /* ip += (A >= X) ? jt : jf */
mask = 0xa00000; /* jhe */
goto xbranch;
case BPF_JMP | BPF_JEQ | BPF_X: /* ip += (A == X) ? jt : jf */
mask = 0x800000; /* je */
xbranch: /* Emit compare if the branch targets are different */
if (filter->jt != filter->jf) {
jit->seen |= SEEN_XREG;
/* cr %r5,%r12 */
EMIT2(0x195c);
}
goto branch;
case BPF_JMP | BPF_JSET | BPF_X: /* ip += (A & X) ? jt : jf */
mask = 0x700000; /* jnz */
/* Emit test if the branch targets are different */
if (filter->jt != filter->jf) {
jit->seen |= SEEN_XREG;
/* lr %r4,%r5 */
EMIT2(0x1845);
/* nr %r4,%r12 */
EMIT2(0x144c);
}
goto branch;
case BPF_LD | BPF_W | BPF_ABS: /* A = *(u32 *) (skb->data+K) */
jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_WORD;
offset = jit->off_load_word;
goto load_abs;
case BPF_LD | BPF_H | BPF_ABS: /* A = *(u16 *) (skb->data+K) */
jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_HALF;
offset = jit->off_load_half;
goto load_abs;
case BPF_LD | BPF_B | BPF_ABS: /* A = *(u8 *) (skb->data+K) */
jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_BYTE;
offset = jit->off_load_byte;
load_abs: if ((int) K < 0)
goto out;
call_fn: /* lg %r1,<d(function)>(%r13) */
EMIT6_DISP(0xe310d000, 0x0004, offset);
/* l %r3,<d(K)>(%r13) */
EMIT4_DISP(0x5830d000, EMIT_CONST(K));
/* basr %r8,%r1 */
EMIT2(0x0d81);
/* jnz <ret0> */
EMIT4_PCREL(0xa7740000, (jit->ret0_ip - jit->prg));
break;
case BPF_LD | BPF_W | BPF_IND: /* A = *(u32 *) (skb->data+K+X) */
jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IWORD;
offset = jit->off_load_iword;
goto call_fn;
case BPF_LD | BPF_H | BPF_IND: /* A = *(u16 *) (skb->data+K+X) */
jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IHALF;
offset = jit->off_load_ihalf;
goto call_fn;
case BPF_LD | BPF_B | BPF_IND: /* A = *(u8 *) (skb->data+K+X) */
jit->seen |= SEEN_DATAREF | SEEN_RET0 | SEEN_LOAD_IBYTE;
offset = jit->off_load_ibyte;
goto call_fn;
case BPF_LDX | BPF_B | BPF_MSH:
/* X = (*(u8 *)(skb->data+K) & 0xf) << 2 */
jit->seen |= SEEN_RET0;
if ((int) K < 0) {
/* j <ret0> */
EMIT4_PCREL(0xa7f40000, (jit->ret0_ip - jit->prg));
break;
}
jit->seen |= SEEN_DATAREF | SEEN_LOAD_BMSH;
offset = jit->off_load_bmsh;
goto call_fn;
case BPF_LD | BPF_W | BPF_LEN: /* A = skb->len; */
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
/* l %r5,<d(len)>(%r2) */
EMIT4_DISP(0x58502000, offsetof(struct sk_buff, len));
break;
case BPF_LDX | BPF_W | BPF_LEN: /* X = skb->len; */
jit->seen |= SEEN_XREG;
/* l %r12,<d(len)>(%r2) */
EMIT4_DISP(0x58c02000, offsetof(struct sk_buff, len));
break;
case BPF_LD | BPF_IMM: /* A = K */
if (K <= 16383)
/* lhi %r5,K */
EMIT4_IMM(0xa7580000, K);
else if (test_facility(21))
/* llilf %r5,<K> */
EMIT6_IMM(0xc05f0000, K);
else
/* l %r5,<d(K)>(%r13) */
EMIT4_DISP(0x5850d000, EMIT_CONST(K));
break;
case BPF_LDX | BPF_IMM: /* X = K */
jit->seen |= SEEN_XREG;
if (K <= 16383)
/* lhi %r12,<K> */
EMIT4_IMM(0xa7c80000, K);
else if (test_facility(21))
/* llilf %r12,<K> */
EMIT6_IMM(0xc0cf0000, K);
else
/* l %r12,<d(K)>(%r13) */
EMIT4_DISP(0x58c0d000, EMIT_CONST(K));
break;
case BPF_LD | BPF_MEM: /* A = mem[K] */
jit->seen |= SEEN_MEM;
/* l %r5,<K>(%r15) */
EMIT4_DISP(0x5850f000,
(jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
break;
case BPF_LDX | BPF_MEM: /* X = mem[K] */
jit->seen |= SEEN_XREG | SEEN_MEM;
/* l %r12,<K>(%r15) */
EMIT4_DISP(0x58c0f000,
(jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
break;
case BPF_MISC | BPF_TAX: /* X = A */
jit->seen |= SEEN_XREG;
/* lr %r12,%r5 */
EMIT2(0x18c5);
break;
case BPF_MISC | BPF_TXA: /* A = X */
jit->seen |= SEEN_XREG;
/* lr %r5,%r12 */
EMIT2(0x185c);
break;
case BPF_RET | BPF_K:
if (K == 0) {
jit->seen |= SEEN_RET0;
if (last)
break;
/* j <ret0> */
EMIT4_PCREL(0xa7f40000, jit->ret0_ip - jit->prg);
} else {
if (K <= 16383)
/* lghi %r2,K */
EMIT4_IMM(0xa7290000, K);
else
/* llgf %r2,<K>(%r13) */
EMIT6_DISP(0xe320d000, 0x0016, EMIT_CONST(K));
/* j <exit> */
if (last && !(jit->seen & SEEN_RET0))
break;
EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
}
break;
case BPF_RET | BPF_A:
/* llgfr %r2,%r5 */
EMIT4(0xb9160025);
/* j <exit> */
EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
break;
case BPF_ST: /* mem[K] = A */
jit->seen |= SEEN_MEM;
/* st %r5,<K>(%r15) */
EMIT4_DISP(0x5050f000,
(jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
break;
case BPF_STX: /* mem[K] = X : mov %ebx,off8(%rbp) */
jit->seen |= SEEN_XREG | SEEN_MEM;
/* st %r12,<K>(%r15) */
EMIT4_DISP(0x50c0f000,
(jit->seen & SEEN_DATAREF) ? 160 + K*4 : K*4);
break;
case BPF_ANC | SKF_AD_PROTOCOL: /* A = ntohs(skb->protocol); */
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
/* lhi %r5,0 */
EMIT4(0xa7580000);
/* icm %r5,3,<d(protocol)>(%r2) */
EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, protocol));
break;
case BPF_ANC | SKF_AD_IFINDEX: /* if (!skb->dev) return 0;
* A = skb->dev->ifindex */
BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
jit->seen |= SEEN_RET0;
/* lg %r1,<d(dev)>(%r2) */
EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
/* ltgr %r1,%r1 */
EMIT4(0xb9020011);
/* jz <ret0> */
EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
/* l %r5,<d(ifindex)>(%r1) */
EMIT4_DISP(0x58501000, offsetof(struct net_device, ifindex));
break;
case BPF_ANC | SKF_AD_MARK: /* A = skb->mark */
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
/* l %r5,<d(mark)>(%r2) */
EMIT4_DISP(0x58502000, offsetof(struct sk_buff, mark));
break;
case BPF_ANC | SKF_AD_QUEUE: /* A = skb->queue_mapping */
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
/* lhi %r5,0 */
EMIT4(0xa7580000);
/* icm %r5,3,<d(queue_mapping)>(%r2) */
EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, queue_mapping));
break;
case BPF_ANC | SKF_AD_HATYPE: /* if (!skb->dev) return 0;
* A = skb->dev->type */
BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
jit->seen |= SEEN_RET0;
/* lg %r1,<d(dev)>(%r2) */
EMIT6_DISP(0xe3102000, 0x0004, offsetof(struct sk_buff, dev));
/* ltgr %r1,%r1 */
EMIT4(0xb9020011);
/* jz <ret0> */
EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
/* lhi %r5,0 */
EMIT4(0xa7580000);
/* icm %r5,3,<d(type)>(%r1) */
EMIT4_DISP(0xbf531000, offsetof(struct net_device, type));
break;
case BPF_ANC | SKF_AD_RXHASH: /* A = skb->hash */
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
/* l %r5,<d(hash)>(%r2) */
EMIT4_DISP(0x58502000, offsetof(struct sk_buff, hash));
break;
case BPF_ANC | SKF_AD_VLAN_TAG:
case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
/* lhi %r5,0 */
EMIT4(0xa7580000);
/* icm %r5,3,<d(vlan_tci)>(%r2) */
EMIT4_DISP(0xbf532000, offsetof(struct sk_buff, vlan_tci));
if (code == (BPF_ANC | SKF_AD_VLAN_TAG)) {
/* nill %r5,0xefff */
EMIT4_IMM(0xa5570000, ~VLAN_TAG_PRESENT);
} else {
/* nill %r5,0x1000 */
EMIT4_IMM(0xa5570000, VLAN_TAG_PRESENT);
/* srl %r5,12 */
EMIT4_DISP(0x88500000, 12);
}
break;
case BPF_ANC | SKF_AD_PKTTYPE:
if (pkt_type_offset < 0)
goto out;
/* lhi %r5,0 */
EMIT4(0xa7580000);
/* ic %r5,<d(pkt_type_offset)>(%r2) */
EMIT4_DISP(0x43502000, pkt_type_offset);
/* srl %r5,5 */
EMIT4_DISP(0x88500000, 5);
break;
case BPF_ANC | SKF_AD_CPU: /* A = smp_processor_id() */
#ifdef CONFIG_SMP
/* l %r5,<d(cpu_nr)> */
EMIT4_DISP(0x58500000, offsetof(struct _lowcore, cpu_nr));
#else
/* lhi %r5,0 */
EMIT4(0xa7580000);
#endif
break;
default: /* too complex, give up */
goto out;
}
addrs[i] = jit->prg - jit->start;
return 0;
out:
return -1;
}
void bpf_jit_compile(struct bpf_prog *fp)
{
struct bpf_binary_header *header = NULL;
unsigned long size, prg_len, lit_len;
struct bpf_jit jit, cjit;
unsigned int *addrs;
int pass, i;
if (!bpf_jit_enable)
return;
addrs = kcalloc(fp->len, sizeof(*addrs), GFP_KERNEL);
if (addrs == NULL)
return;
memset(&jit, 0, sizeof(cjit));
memset(&cjit, 0, sizeof(cjit));
for (pass = 0; pass < 10; pass++) {
jit.prg = jit.start;
jit.lit = jit.mid;
bpf_jit_prologue(&jit);
bpf_jit_noleaks(&jit, fp->insns);
for (i = 0; i < fp->len; i++) {
if (bpf_jit_insn(&jit, fp->insns + i, addrs, i,
i == fp->len - 1))
goto out;
}
bpf_jit_epilogue(&jit);
if (jit.start) {
WARN_ON(jit.prg > cjit.prg || jit.lit > cjit.lit);
if (memcmp(&jit, &cjit, sizeof(jit)) == 0)
break;
} else if (jit.prg == cjit.prg && jit.lit == cjit.lit) {
prg_len = jit.prg - jit.start;
lit_len = jit.lit - jit.mid;
size = prg_len + lit_len;
if (size >= BPF_SIZE_MAX)
goto out;
header = bpf_jit_binary_alloc(size, &jit.start,
2, bpf_jit_fill_hole);
if (!header)
goto out;
jit.prg = jit.mid = jit.start + prg_len;
jit.lit = jit.end = jit.start + prg_len + lit_len;
jit.base_ip += (unsigned long) jit.start;
jit.exit_ip += (unsigned long) jit.start;
jit.ret0_ip += (unsigned long) jit.start;
}
cjit = jit;
}
if (bpf_jit_enable > 1) {
bpf_jit_dump(fp->len, jit.end - jit.start, pass, jit.start);
if (jit.start)
print_fn_code(jit.start, jit.mid - jit.start);
}
if (jit.start) {
set_memory_ro((unsigned long)header, header->pages);
fp->bpf_func = (void *) jit.start;
fp->jited = 1;
}
out:
kfree(addrs);
}
void bpf_jit_free(struct bpf_prog *fp)
{
unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
struct bpf_binary_header *header = (void *)addr;
if (!fp->jited)
goto free_filter;
set_memory_rw(addr, header->pages);
bpf_jit_binary_free(header);
free_filter:
bpf_prog_unlock_free(fp);
}
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