- 根目录:
- arch
- s390
- net
- bpf_jit_comp.c
/*
* BPF Jit compiler for s390.
*
* Minimum build requirements:
*
* - HAVE_MARCH_Z196_FEATURES: laal, laalg
* - HAVE_MARCH_Z10_FEATURES: msfi, cgrj, clgrj
* - HAVE_MARCH_Z9_109_FEATURES: alfi, llilf, clfi, oilf, nilf
* - PACK_STACK
* - 64BIT
*
* Copyright IBM Corp. 2012,2015
*
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
* Michael Holzheu <holzheu@linux.vnet.ibm.com>
*/
#define KMSG_COMPONENT "bpf_jit"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/netdevice.h>
#include <linux/filter.h>
#include <linux/init.h>
#include <linux/bpf.h>
#include <asm/cacheflush.h>
#include <asm/dis.h>
#include "bpf_jit.h"
int bpf_jit_enable __read_mostly;
struct bpf_jit {
u32 seen; /* Flags to remember seen eBPF instructions */
u32 seen_reg[16]; /* Array to remember which registers are used */
u32 *addrs; /* Array with relative instruction addresses */
u8 *prg_buf; /* Start of program */
int size; /* Size of program and literal pool */
int size_prg; /* Size of program */
int prg; /* Current position in program */
int lit_start; /* Start of literal pool */
int lit; /* Current position in literal pool */
int base_ip; /* Base address for literal pool */
int ret0_ip; /* Address of return 0 */
int exit_ip; /* Address of exit */
int tail_call_start; /* Tail call start offset */
int labels[1]; /* Labels for local jumps */
};
#define BPF_SIZE_MAX 0x7ffff /* Max size for program (20 bit signed displ) */
#define SEEN_SKB 1 /* skb access */
#define SEEN_MEM 2 /* use mem[] for temporary storage */
#define SEEN_RET0 4 /* ret0_ip points to a valid return 0 */
#define SEEN_LITERAL 8 /* code uses literals */
#define SEEN_FUNC 16 /* calls C functions */
#define SEEN_TAIL_CALL 32 /* code uses tail calls */
#define SEEN_SKB_CHANGE 64 /* code changes skb data */
#define SEEN_STACK (SEEN_FUNC | SEEN_MEM | SEEN_SKB)
/*
* s390 registers
*/
#define REG_W0 (__MAX_BPF_REG+0) /* Work register 1 (even) */
#define REG_W1 (__MAX_BPF_REG+1) /* Work register 2 (odd) */
#define REG_SKB_DATA (__MAX_BPF_REG+2) /* SKB data register */
#define REG_L (__MAX_BPF_REG+3) /* Literal pool register */
#define REG_15 (__MAX_BPF_REG+4) /* Register 15 */
#define REG_0 REG_W0 /* Register 0 */
#define REG_1 REG_W1 /* Register 1 */
#define REG_2 BPF_REG_1 /* Register 2 */
#define REG_14 BPF_REG_0 /* Register 14 */
/*
* Mapping of BPF registers to s390 registers
*/
static const int reg2hex[] = {
/* Return code */
[BPF_REG_0] = 14,
/* Function parameters */
[BPF_REG_1] = 2,
[BPF_REG_2] = 3,
[BPF_REG_3] = 4,
[BPF_REG_4] = 5,
[BPF_REG_5] = 6,
/* Call saved registers */
[BPF_REG_6] = 7,
[BPF_REG_7] = 8,
[BPF_REG_8] = 9,
[BPF_REG_9] = 10,
/* BPF stack pointer */
[BPF_REG_FP] = 13,
/* SKB data pointer */
[REG_SKB_DATA] = 12,
/* Work registers for s390x backend */
[REG_W0] = 0,
[REG_W1] = 1,
[REG_L] = 11,
[REG_15] = 15,
};
static inline u32 reg(u32 dst_reg, u32 src_reg)
{
return reg2hex[dst_reg] << 4 | reg2hex[src_reg];
}
static inline u32 reg_high(u32 reg)
{
return reg2hex[reg] << 4;
}
static inline void reg_set_seen(struct bpf_jit *jit, u32 b1)
{
u32 r1 = reg2hex[b1];
if (!jit->seen_reg[r1] && r1 >= 6 && r1 <= 15)
jit->seen_reg[r1] = 1;
}
#define REG_SET_SEEN(b1) \
({ \
reg_set_seen(jit, b1); \
})
#define REG_SEEN(b1) jit->seen_reg[reg2hex[(b1)]]
/*
* EMIT macros for code generation
*/
#define _EMIT2(op) \
({ \
if (jit->prg_buf) \
*(u16 *) (jit->prg_buf + jit->prg) = op; \
jit->prg += 2; \
})
#define EMIT2(op, b1, b2) \
({ \
_EMIT2(op | reg(b1, b2)); \
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
})
#define _EMIT4(op) \
({ \
if (jit->prg_buf) \
*(u32 *) (jit->prg_buf + jit->prg) = op; \
jit->prg += 4; \
})
#define EMIT4(op, b1, b2) \
({ \
_EMIT4(op | reg(b1, b2)); \
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
})
#define EMIT4_RRF(op, b1, b2, b3) \
({ \
_EMIT4(op | reg_high(b3) << 8 | reg(b1, b2)); \
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
REG_SET_SEEN(b3); \
})
#define _EMIT4_DISP(op, disp) \
({ \
unsigned int __disp = (disp) & 0xfff; \
_EMIT4(op | __disp); \
})
#define EMIT4_DISP(op, b1, b2, disp) \
({ \
_EMIT4_DISP(op | reg_high(b1) << 16 | \
reg_high(b2) << 8, disp); \
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
})
#define EMIT4_IMM(op, b1, imm) \
({ \
unsigned int __imm = (imm) & 0xffff; \
_EMIT4(op | reg_high(b1) << 16 | __imm); \
REG_SET_SEEN(b1); \
})
#define EMIT4_PCREL(op, pcrel) \
({ \
long __pcrel = ((pcrel) >> 1) & 0xffff; \
_EMIT4(op | __pcrel); \
})
#define _EMIT6(op1, op2) \
({ \
if (jit->prg_buf) { \
*(u32 *) (jit->prg_buf + jit->prg) = op1; \
*(u16 *) (jit->prg_buf + jit->prg + 4) = op2; \
} \
jit->prg += 6; \
})
#define _EMIT6_DISP(op1, op2, disp) \
({ \
unsigned int __disp = (disp) & 0xfff; \
_EMIT6(op1 | __disp, op2); \
})
#define _EMIT6_DISP_LH(op1, op2, disp) \
({ \
u32 _disp = (u32) disp; \
unsigned int __disp_h = _disp & 0xff000; \
unsigned int __disp_l = _disp & 0x00fff; \
_EMIT6(op1 | __disp_l, op2 | __disp_h >> 4); \
})
#define EMIT6_DISP_LH(op1, op2, b1, b2, b3, disp) \
({ \
_EMIT6_DISP_LH(op1 | reg(b1, b2) << 16 | \
reg_high(b3) << 8, op2, disp); \
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
REG_SET_SEEN(b3); \
})
#define EMIT6_PCREL_LABEL(op1, op2, b1, b2, label, mask) \
({ \
int rel = (jit->labels[label] - jit->prg) >> 1; \
_EMIT6(op1 | reg(b1, b2) << 16 | (rel & 0xffff), \
op2 | mask << 12); \
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
})
#define EMIT6_PCREL_IMM_LABEL(op1, op2, b1, imm, label, mask) \
({ \
int rel = (jit->labels[label] - jit->prg) >> 1; \
_EMIT6(op1 | (reg_high(b1) | mask) << 16 | \
(rel & 0xffff), op2 | (imm & 0xff) << 8); \
REG_SET_SEEN(b1); \
BUILD_BUG_ON(((unsigned long) imm) > 0xff); \
})
#define EMIT6_PCREL(op1, op2, b1, b2, i, off, mask) \
({ \
/* Branch instruction needs 6 bytes */ \
int rel = (addrs[i + off + 1] - (addrs[i + 1] - 6)) / 2;\
_EMIT6(op1 | reg(b1, b2) << 16 | (rel & 0xffff), op2 | mask); \
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
})
#define _EMIT6_IMM(op, imm) \
({ \
unsigned int __imm = (imm); \
_EMIT6(op | (__imm >> 16), __imm & 0xffff); \
})
#define EMIT6_IMM(op, b1, imm) \
({ \
_EMIT6_IMM(op | reg_high(b1) << 16, imm); \
REG_SET_SEEN(b1); \
})
#define EMIT_CONST_U32(val) \
({ \
unsigned int ret; \
ret = jit->lit - jit->base_ip; \
jit->seen |= SEEN_LITERAL; \
if (jit->prg_buf) \
*(u32 *) (jit->prg_buf + jit->lit) = (u32) val; \
jit->lit += 4; \
ret; \
})
#define EMIT_CONST_U64(val) \
({ \
unsigned int ret; \
ret = jit->lit - jit->base_ip; \
jit->seen |= SEEN_LITERAL; \
if (jit->prg_buf) \
*(u64 *) (jit->prg_buf + jit->lit) = (u64) val; \
jit->lit += 8; \
ret; \
})
#define EMIT_ZERO(b1) \
({ \
/* llgfr %dst,%dst (zero extend to 64 bit) */ \
EMIT4(0xb9160000, b1, b1); \
REG_SET_SEEN(b1); \
})
/*
* Fill whole space with illegal instructions
*/
static void jit_fill_hole(void *area, unsigned int size)
{
memset(area, 0, size);
}
/*
* Save registers from "rs" (register start) to "re" (register end) on stack
*/
static void save_regs(struct bpf_jit *jit, u32 rs, u32 re)
{
u32 off = STK_OFF_R6 + (rs - 6) * 8;
if (rs == re)
/* stg %rs,off(%r15) */
_EMIT6(0xe300f000 | rs << 20 | off, 0x0024);
else
/* stmg %rs,%re,off(%r15) */
_EMIT6_DISP(0xeb00f000 | rs << 20 | re << 16, 0x0024, off);
}
/*
* Restore registers from "rs" (register start) to "re" (register end) on stack
*/
static void restore_regs(struct bpf_jit *jit, u32 rs, u32 re)
{
u32 off = STK_OFF_R6 + (rs - 6) * 8;
if (jit->seen & SEEN_STACK)
off += STK_OFF;
if (rs == re)
/* lg %rs,off(%r15) */
_EMIT6(0xe300f000 | rs << 20 | off, 0x0004);
else
/* lmg %rs,%re,off(%r15) */
_EMIT6_DISP(0xeb00f000 | rs << 20 | re << 16, 0x0004, off);
}
/*
* Return first seen register (from start)
*/
static int get_start(struct bpf_jit *jit, int start)
{
int i;
for (i = start; i <= 15; i++) {
if (jit->seen_reg[i])
return i;
}
return 0;
}
/*
* Return last seen register (from start) (gap >= 2)
*/
static int get_end(struct bpf_jit *jit, int start)
{
int i;
for (i = start; i < 15; i++) {
if (!jit->seen_reg[i] && !jit->seen_reg[i + 1])
return i - 1;
}
return jit->seen_reg[15] ? 15 : 14;
}
#define REGS_SAVE 1
#define REGS_RESTORE 0
/*
* Save and restore clobbered registers (6-15) on stack.
* We save/restore registers in chunks with gap >= 2 registers.
*/
static void save_restore_regs(struct bpf_jit *jit, int op)
{
int re = 6, rs;
do {
rs = get_start(jit, re);
if (!rs)
break;
re = get_end(jit, rs + 1);
if (op == REGS_SAVE)
save_regs(jit, rs, re);
else
restore_regs(jit, rs, re);
re++;
} while (re <= 15);
}
/*
* For SKB access %b1 contains the SKB pointer. For "bpf_jit.S"
* we store the SKB header length on the stack and the SKB data
* pointer in REG_SKB_DATA.
*/
static void emit_load_skb_data_hlen(struct bpf_jit *jit)
{
/* Header length: llgf %w1,<len>(%b1) */
EMIT6_DISP_LH(0xe3000000, 0x0016, REG_W1, REG_0, BPF_REG_1,
offsetof(struct sk_buff, len));
/* s %w1,<data_len>(%b1) */
EMIT4_DISP(0x5b000000, REG_W1, BPF_REG_1,
offsetof(struct sk_buff, data_len));
/* stg %w1,ST_OFF_HLEN(%r0,%r15) */
EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0, REG_15, STK_OFF_HLEN);
/* lg %skb_data,data_off(%b1) */
EMIT6_DISP_LH(0xe3000000, 0x0004, REG_SKB_DATA, REG_0,
BPF_REG_1, offsetof(struct sk_buff, data));
}
/*
* Emit function prologue
*
* Save registers and create stack frame if necessary.
* See stack frame layout desription in "bpf_jit.h"!
*/
static void bpf_jit_prologue(struct bpf_jit *jit, bool is_classic)
{
if (jit->seen & SEEN_TAIL_CALL) {
/* xc STK_OFF_TCCNT(4,%r15),STK_OFF_TCCNT(%r15) */
_EMIT6(0xd703f000 | STK_OFF_TCCNT, 0xf000 | STK_OFF_TCCNT);
} else {
/* j tail_call_start: NOP if no tail calls are used */
EMIT4_PCREL(0xa7f40000, 6);
_EMIT2(0);
}
/* Tail calls have to skip above initialization */
jit->tail_call_start = jit->prg;
/* Save registers */
save_restore_regs(jit, REGS_SAVE);
/* Setup literal pool */
if (jit->seen & SEEN_LITERAL) {
/* basr %r13,0 */
EMIT2(0x0d00, REG_L, REG_0);
jit->base_ip = jit->prg;
}
/* Setup stack and backchain */
if (jit->seen & SEEN_STACK) {
if (jit->seen & SEEN_FUNC)
/* lgr %w1,%r15 (backchain) */
EMIT4(0xb9040000, REG_W1, REG_15);
/* la %bfp,STK_160_UNUSED(%r15) (BPF frame pointer) */
EMIT4_DISP(0x41000000, BPF_REG_FP, REG_15, STK_160_UNUSED);
/* aghi %r15,-STK_OFF */
EMIT4_IMM(0xa70b0000, REG_15, -STK_OFF);
if (jit->seen & SEEN_FUNC)
/* stg %w1,152(%r15) (backchain) */
EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0,
REG_15, 152);
}
if (jit->seen & SEEN_SKB)
emit_load_skb_data_hlen(jit);
if (jit->seen & SEEN_SKB_CHANGE)
/* stg %b1,ST_OFF_SKBP(%r0,%r15) */
EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0, REG_15,
STK_OFF_SKBP);
/* Clear A (%b0) and X (%b7) registers for converted BPF programs */
if (is_classic) {
if (REG_SEEN(BPF_REG_A))
/* lghi %ba,0 */
EMIT4_IMM(0xa7090000, BPF_REG_A, 0);
if (REG_SEEN(BPF_REG_X))
/* lghi %bx,0 */
EMIT4_IMM(0xa7090000, BPF_REG_X, 0);
}
}
/*
* Function epilogue
*/
static void bpf_jit_epilogue(struct bpf_jit *jit)
{
/* Return 0 */
if (jit->seen & SEEN_RET0) {
jit->ret0_ip = jit->prg;
/* lghi %b0,0 */
EMIT4_IMM(0xa7090000, BPF_REG_0, 0);
}
jit->exit_ip = jit->prg;
/* Load exit code: lgr %r2,%b0 */
EMIT4(0xb9040000, REG_2, BPF_REG_0);
/* Restore registers */
save_restore_regs(jit, REGS_RESTORE);
/* br %r14 */
_EMIT2(0x07fe);
}
/*
* Compile one eBPF instruction into s390x code
*
* NOTE: Use noinline because for gcov (-fprofile-arcs) gcc allocates a lot of
* stack space for the large switch statement.
*/
static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i)
{
struct bpf_insn *insn = &fp->insnsi[i];
int jmp_off, last, insn_count = 1;
unsigned int func_addr, mask;
u32 dst_reg = insn->dst_reg;
u32 src_reg = insn->src_reg;
u32 *addrs = jit->addrs;
s32 imm = insn->imm;
s16 off = insn->off;
switch (insn->code) {
/*
* BPF_MOV
*/
case BPF_ALU | BPF_MOV | BPF_X: /* dst = (u32) src */
/* llgfr %dst,%src */
EMIT4(0xb9160000, dst_reg, src_reg);
break;
case BPF_ALU64 | BPF_MOV | BPF_X: /* dst = src */
/* lgr %dst,%src */
EMIT4(0xb9040000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_MOV | BPF_K: /* dst = (u32) imm */
/* llilf %dst,imm */
EMIT6_IMM(0xc00f0000, dst_reg, imm);
break;
case BPF_ALU64 | BPF_MOV | BPF_K: /* dst = imm */
/* lgfi %dst,imm */
EMIT6_IMM(0xc0010000, dst_reg, imm);
break;
/*
* BPF_LD 64
*/
case BPF_LD | BPF_IMM | BPF_DW: /* dst = (u64) imm */
{
/* 16 byte instruction that uses two 'struct bpf_insn' */
u64 imm64;
imm64 = (u64)(u32) insn[0].imm | ((u64)(u32) insn[1].imm) << 32;
/* lg %dst,<d(imm)>(%l) */
EMIT6_DISP_LH(0xe3000000, 0x0004, dst_reg, REG_0, REG_L,
EMIT_CONST_U64(imm64));
insn_count = 2;
break;
}
/*
* BPF_ADD
*/
case BPF_ALU | BPF_ADD | BPF_X: /* dst = (u32) dst + (u32) src */
/* ar %dst,%src */
EMIT2(0x1a00, dst_reg, src_reg);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_ADD | BPF_X: /* dst = dst + src */
/* agr %dst,%src */
EMIT4(0xb9080000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_ADD | BPF_K: /* dst = (u32) dst + (u32) imm */
if (!imm)
break;
/* alfi %dst,imm */
EMIT6_IMM(0xc20b0000, dst_reg, imm);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_ADD | BPF_K: /* dst = dst + imm */
if (!imm)
break;
/* agfi %dst,imm */
EMIT6_IMM(0xc2080000, dst_reg, imm);
break;
/*
* BPF_SUB
*/
case BPF_ALU | BPF_SUB | BPF_X: /* dst = (u32) dst - (u32) src */
/* sr %dst,%src */
EMIT2(0x1b00, dst_reg, src_reg);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_SUB | BPF_X: /* dst = dst - src */
/* sgr %dst,%src */
EMIT4(0xb9090000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_SUB | BPF_K: /* dst = (u32) dst - (u32) imm */
if (!imm)
break;
/* alfi %dst,-imm */
EMIT6_IMM(0xc20b0000, dst_reg, -imm);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_SUB | BPF_K: /* dst = dst - imm */
if (!imm)
break;
/* agfi %dst,-imm */
EMIT6_IMM(0xc2080000, dst_reg, -imm);
break;
/*
* BPF_MUL
*/
case BPF_ALU | BPF_MUL | BPF_X: /* dst = (u32) dst * (u32) src */
/* msr %dst,%src */
EMIT4(0xb2520000, dst_reg, src_reg);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_MUL | BPF_X: /* dst = dst * src */
/* msgr %dst,%src */
EMIT4(0xb90c0000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_MUL | BPF_K: /* dst = (u32) dst * (u32) imm */
if (imm == 1)
break;
/* msfi %r5,imm */
EMIT6_IMM(0xc2010000, dst_reg, imm);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_MUL | BPF_K: /* dst = dst * imm */
if (imm == 1)
break;
/* msgfi %dst,imm */
EMIT6_IMM(0xc2000000, dst_reg, imm);
break;
/*
* BPF_DIV / BPF_MOD
*/
case BPF_ALU | BPF_DIV | BPF_X: /* dst = (u32) dst / (u32) src */
case BPF_ALU | BPF_MOD | BPF_X: /* dst = (u32) dst % (u32) src */
{
int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
jit->seen |= SEEN_RET0;
/* ltr %src,%src (if src == 0 goto fail) */
EMIT2(0x1200, src_reg, src_reg);
/* jz <ret0> */
EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
/* lhi %w0,0 */
EMIT4_IMM(0xa7080000, REG_W0, 0);
/* lr %w1,%dst */
EMIT2(0x1800, REG_W1, dst_reg);
/* dlr %w0,%src */
EMIT4(0xb9970000, REG_W0, src_reg);
/* llgfr %dst,%rc */
EMIT4(0xb9160000, dst_reg, rc_reg);
break;
}
case BPF_ALU64 | BPF_DIV | BPF_X: /* dst = dst / src */
case BPF_ALU64 | BPF_MOD | BPF_X: /* dst = dst % src */
{
int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
jit->seen |= SEEN_RET0;
/* ltgr %src,%src (if src == 0 goto fail) */
EMIT4(0xb9020000, src_reg, src_reg);
/* jz <ret0> */
EMIT4_PCREL(0xa7840000, jit->ret0_ip - jit->prg);
/* lghi %w0,0 */
EMIT4_IMM(0xa7090000, REG_W0, 0);
/* lgr %w1,%dst */
EMIT4(0xb9040000, REG_W1, dst_reg);
/* dlgr %w0,%dst */
EMIT4(0xb9870000, REG_W0, src_reg);
/* lgr %dst,%rc */
EMIT4(0xb9040000, dst_reg, rc_reg);
break;
}
case BPF_ALU | BPF_DIV | BPF_K: /* dst = (u32) dst / (u32) imm */
case BPF_ALU | BPF_MOD | BPF_K: /* dst = (u32) dst % (u32) imm */
{
int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
if (imm == 1) {
if (BPF_OP(insn->code) == BPF_MOD)
/* lhgi %dst,0 */
EMIT4_IMM(0xa7090000, dst_reg, 0);
break;
}
/* lhi %w0,0 */
EMIT4_IMM(0xa7080000, REG_W0, 0);
/* lr %w1,%dst */
EMIT2(0x1800, REG_W1, dst_reg);
/* dl %w0,<d(imm)>(%l) */
EMIT6_DISP_LH(0xe3000000, 0x0097, REG_W0, REG_0, REG_L,
EMIT_CONST_U32(imm));
/* llgfr %dst,%rc */
EMIT4(0xb9160000, dst_reg, rc_reg);
break;
}
case BPF_ALU64 | BPF_DIV | BPF_K: /* dst = dst / imm */
case BPF_ALU64 | BPF_MOD | BPF_K: /* dst = dst % imm */
{
int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
if (imm == 1) {
if (BPF_OP(insn->code) == BPF_MOD)
/* lhgi %dst,0 */
EMIT4_IMM(0xa7090000, dst_reg, 0);
break;
}
/* lghi %w0,0 */
EMIT4_IMM(0xa7090000, REG_W0, 0);
/* lgr %w1,%dst */
EMIT4(0xb9040000, REG_W1, dst_reg);
/* dlg %w0,<d(imm)>(%l) */
EMIT6_DISP_LH(0xe3000000, 0x0087, REG_W0, REG_0, REG_L,
EMIT_CONST_U64(imm));
/* lgr %dst,%rc */
EMIT4(0xb9040000, dst_reg, rc_reg);
break;
}
/*
* BPF_AND
*/
case BPF_ALU | BPF_AND | BPF_X: /* dst = (u32) dst & (u32) src */
/* nr %dst,%src */
EMIT2(0x1400, dst_reg, src_reg);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_AND | BPF_X: /* dst = dst & src */
/* ngr %dst,%src */
EMIT4(0xb9800000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_AND | BPF_K: /* dst = (u32) dst & (u32) imm */
/* nilf %dst,imm */
EMIT6_IMM(0xc00b0000, dst_reg, imm);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_AND | BPF_K: /* dst = dst & imm */
/* ng %dst,<d(imm)>(%l) */
EMIT6_DISP_LH(0xe3000000, 0x0080, dst_reg, REG_0, REG_L,
EMIT_CONST_U64(imm));
break;
/*
* BPF_OR
*/
case BPF_ALU | BPF_OR | BPF_X: /* dst = (u32) dst | (u32) src */
/* or %dst,%src */
EMIT2(0x1600, dst_reg, src_reg);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_OR | BPF_X: /* dst = dst | src */
/* ogr %dst,%src */
EMIT4(0xb9810000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_OR | BPF_K: /* dst = (u32) dst | (u32) imm */
/* oilf %dst,imm */
EMIT6_IMM(0xc00d0000, dst_reg, imm);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_OR | BPF_K: /* dst = dst | imm */
/* og %dst,<d(imm)>(%l) */
EMIT6_DISP_LH(0xe3000000, 0x0081, dst_reg, REG_0, REG_L,
EMIT_CONST_U64(imm));
break;
/*
* BPF_XOR
*/
case BPF_ALU | BPF_XOR | BPF_X: /* dst = (u32) dst ^ (u32) src */
/* xr %dst,%src */
EMIT2(0x1700, dst_reg, src_reg);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_XOR | BPF_X: /* dst = dst ^ src */
/* xgr %dst,%src */
EMIT4(0xb9820000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_XOR | BPF_K: /* dst = (u32) dst ^ (u32) imm */
if (!imm)
break;
/* xilf %dst,imm */
EMIT6_IMM(0xc0070000, dst_reg, imm);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_XOR | BPF_K: /* dst = dst ^ imm */
/* xg %dst,<d(imm)>(%l) */
EMIT6_DISP_LH(0xe3000000, 0x0082, dst_reg, REG_0, REG_L,
EMIT_CONST_U64(imm));
break;
/*
* BPF_LSH
*/
case BPF_ALU | BPF_LSH | BPF_X: /* dst = (u32) dst << (u32) src */
/* sll %dst,0(%src) */
EMIT4_DISP(0x89000000, dst_reg, src_reg, 0);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_LSH | BPF_X: /* dst = dst << src */
/* sllg %dst,%dst,0(%src) */
EMIT6_DISP_LH(0xeb000000, 0x000d, dst_reg, dst_reg, src_reg, 0);
break;
case BPF_ALU | BPF_LSH | BPF_K: /* dst = (u32) dst << (u32) imm */
if (imm == 0)
break;
/* sll %dst,imm(%r0) */
EMIT4_DISP(0x89000000, dst_reg, REG_0, imm);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_LSH | BPF_K: /* dst = dst << imm */
if (imm == 0)
break;
/* sllg %dst,%dst,imm(%r0) */
EMIT6_DISP_LH(0xeb000000, 0x000d, dst_reg, dst_reg, REG_0, imm);
break;
/*
* BPF_RSH
*/
case BPF_ALU | BPF_RSH | BPF_X: /* dst = (u32) dst >> (u32) src */
/* srl %dst,0(%src) */
EMIT4_DISP(0x88000000, dst_reg, src_reg, 0);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_RSH | BPF_X: /* dst = dst >> src */
/* srlg %dst,%dst,0(%src) */
EMIT6_DISP_LH(0xeb000000, 0x000c, dst_reg, dst_reg, src_reg, 0);
break;
case BPF_ALU | BPF_RSH | BPF_K: /* dst = (u32) dst >> (u32) imm */
if (imm == 0)
break;
/* srl %dst,imm(%r0) */
EMIT4_DISP(0x88000000, dst_reg, REG_0, imm);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_RSH | BPF_K: /* dst = dst >> imm */
if (imm == 0)
break;
/* srlg %dst,%dst,imm(%r0) */
EMIT6_DISP_LH(0xeb000000, 0x000c, dst_reg, dst_reg, REG_0, imm);
break;
/*
* BPF_ARSH
*/
case BPF_ALU64 | BPF_ARSH | BPF_X: /* ((s64) dst) >>= src */
/* srag %dst,%dst,0(%src) */
EMIT6_DISP_LH(0xeb000000, 0x000a, dst_reg, dst_reg, src_reg, 0);
break;
case BPF_ALU64 | BPF_ARSH | BPF_K: /* ((s64) dst) >>= imm */
if (imm == 0)
break;
/* srag %dst,%dst,imm(%r0) */
EMIT6_DISP_LH(0xeb000000, 0x000a, dst_reg, dst_reg, REG_0, imm);
break;
/*
* BPF_NEG
*/
case BPF_ALU | BPF_NEG: /* dst = (u32) -dst */
/* lcr %dst,%dst */
EMIT2(0x1300, dst_reg, dst_reg);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_NEG: /* dst = -dst */
/* lcgr %dst,%dst */
EMIT4(0xb9130000, dst_reg, dst_reg);
break;
/*
* BPF_FROM_BE/LE
*/
case BPF_ALU | BPF_END | BPF_FROM_BE:
/* s390 is big endian, therefore only clear high order bytes */
switch (imm) {
case 16: /* dst = (u16) cpu_to_be16(dst) */
/* llghr %dst,%dst */
EMIT4(0xb9850000, dst_reg, dst_reg);
break;
case 32: /* dst = (u32) cpu_to_be32(dst) */
/* llgfr %dst,%dst */
EMIT4(0xb9160000, dst_reg, dst_reg);
break;
case 64: /* dst = (u64) cpu_to_be64(dst) */
break;
}
break;
case BPF_ALU | BPF_END | BPF_FROM_LE:
switch (imm) {
case 16: /* dst = (u16) cpu_to_le16(dst) */
/* lrvr %dst,%dst */
EMIT4(0xb91f0000, dst_reg, dst_reg);
/* srl %dst,16(%r0) */
EMIT4_DISP(0x88000000, dst_reg, REG_0, 16);
/* llghr %dst,%dst */
EMIT4(0xb9850000, dst_reg, dst_reg);
break;
case 32: /* dst = (u32) cpu_to_le32(dst) */
/* lrvr %dst,%dst */
EMIT4(0xb91f0000, dst_reg, dst_reg);
/* llgfr %dst,%dst */
EMIT4(0xb9160000, dst_reg, dst_reg);
break;
case 64: /* dst = (u64) cpu_to_le64(dst) */
/* lrvgr %dst,%dst */
EMIT4(0xb90f0000, dst_reg, dst_reg);
break;
}
break;
/*
* BPF_ST(X)
*/
case BPF_STX | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = src_reg */
/* stcy %src,off(%dst) */
EMIT6_DISP_LH(0xe3000000, 0x0072, src_reg, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_STX | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = src */
/* sthy %src,off(%dst) */
EMIT6_DISP_LH(0xe3000000, 0x0070, src_reg, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_STX | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = src */
/* sty %src,off(%dst) */
EMIT6_DISP_LH(0xe3000000, 0x0050, src_reg, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_STX | BPF_MEM | BPF_DW: /* (u64 *)(dst + off) = src */
/* stg %src,off(%dst) */
EMIT6_DISP_LH(0xe3000000, 0x0024, src_reg, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_ST | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = imm */
/* lhi %w0,imm */
EMIT4_IMM(0xa7080000, REG_W0, (u8) imm);
/* stcy %w0,off(dst) */
EMIT6_DISP_LH(0xe3000000, 0x0072, REG_W0, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_ST | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = imm */
/* lhi %w0,imm */
EMIT4_IMM(0xa7080000, REG_W0, (u16) imm);
/* sthy %w0,off(dst) */
EMIT6_DISP_LH(0xe3000000, 0x0070, REG_W0, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_ST | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = imm */
/* llilf %w0,imm */
EMIT6_IMM(0xc00f0000, REG_W0, (u32) imm);
/* sty %w0,off(%dst) */
EMIT6_DISP_LH(0xe3000000, 0x0050, REG_W0, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_ST | BPF_MEM | BPF_DW: /* *(u64 *)(dst + off) = imm */
/* lgfi %w0,imm */
EMIT6_IMM(0xc0010000, REG_W0, imm);
/* stg %w0,off(%dst) */
EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W0, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
/*
* BPF_STX XADD (atomic_add)
*/
case BPF_STX | BPF_XADD | BPF_W: /* *(u32 *)(dst + off) += src */
/* laal %w0,%src,off(%dst) */
EMIT6_DISP_LH(0xeb000000, 0x00fa, REG_W0, src_reg,
dst_reg, off);
jit->seen |= SEEN_MEM;
break;
case BPF_STX | BPF_XADD | BPF_DW: /* *(u64 *)(dst + off) += src */
/* laalg %w0,%src,off(%dst) */
EMIT6_DISP_LH(0xeb000000, 0x00ea, REG_W0, src_reg,
dst_reg, off);
jit->seen |= SEEN_MEM;
break;
/*
* BPF_LDX
*/
case BPF_LDX | BPF_MEM | BPF_B: /* dst = *(u8 *)(ul) (src + off) */
/* llgc %dst,0(off,%src) */
EMIT6_DISP_LH(0xe3000000, 0x0090, dst_reg, src_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_LDX | BPF_MEM | BPF_H: /* dst = *(u16 *)(ul) (src + off) */
/* llgh %dst,0(off,%src) */
EMIT6_DISP_LH(0xe3000000, 0x0091, dst_reg, src_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_LDX | BPF_MEM | BPF_W: /* dst = *(u32 *)(ul) (src + off) */
/* llgf %dst,off(%src) */
jit->seen |= SEEN_MEM;
EMIT6_DISP_LH(0xe3000000, 0x0016, dst_reg, src_reg, REG_0, off);
break;
case BPF_LDX | BPF_MEM | BPF_DW: /* dst = *(u64 *)(ul) (src + off) */
/* lg %dst,0(off,%src) */
jit->seen |= SEEN_MEM;
EMIT6_DISP_LH(0xe3000000, 0x0004, dst_reg, src_reg, REG_0, off);
break;
/*
* BPF_JMP / CALL
*/
case BPF_JMP | BPF_CALL:
{
/*
* b0 = (__bpf_call_base + imm)(b1, b2, b3, b4, b5)
*/
const u64 func = (u64)__bpf_call_base + imm;
REG_SET_SEEN(BPF_REG_5);
jit->seen |= SEEN_FUNC;
/* lg %w1,<d(imm)>(%l) */
EMIT6_DISP_LH(0xe3000000, 0x0004, REG_W1, REG_0, REG_L,
EMIT_CONST_U64(func));
/* basr %r14,%w1 */
EMIT2(0x0d00, REG_14, REG_W1);
/* lgr %b0,%r2: load return value into %b0 */
EMIT4(0xb9040000, BPF_REG_0, REG_2);
if (bpf_helper_changes_skb_data((void *)func)) {
jit->seen |= SEEN_SKB_CHANGE;
/* lg %b1,ST_OFF_SKBP(%r15) */
EMIT6_DISP_LH(0xe3000000, 0x0004, BPF_REG_1, REG_0,
REG_15, STK_OFF_SKBP);
emit_load_skb_data_hlen(jit);
}
break;
}
case BPF_JMP | BPF_CALL | BPF_X:
/*
* Implicit input:
* B1: pointer to ctx
* B2: pointer to bpf_array
* B3: index in bpf_array
*/
jit->seen |= SEEN_TAIL_CALL;
/*
* if (index >= array->map.max_entries)
* goto out;
*/
/* llgf %w1,map.max_entries(%b2) */
EMIT6_DISP_LH(0xe3000000, 0x0016, REG_W1, REG_0, BPF_REG_2,
offsetof(struct bpf_array, map.max_entries));
/* clgrj %b3,%w1,0xa,label0: if %b3 >= %w1 goto out */
EMIT6_PCREL_LABEL(0xec000000, 0x0065, BPF_REG_3,
REG_W1, 0, 0xa);
/*
* if (tail_call_cnt++ > MAX_TAIL_CALL_CNT)
* goto out;
*/
if (jit->seen & SEEN_STACK)
off = STK_OFF_TCCNT + STK_OFF;
else
off = STK_OFF_TCCNT;
/* lhi %w0,1 */
EMIT4_IMM(0xa7080000, REG_W0, 1);
/* laal %w1,%w0,off(%r15) */
EMIT6_DISP_LH(0xeb000000, 0x00fa, REG_W1, REG_W0, REG_15, off);
/* clij %w1,MAX_TAIL_CALL_CNT,0x2,label0 */
EMIT6_PCREL_IMM_LABEL(0xec000000, 0x007f, REG_W1,
MAX_TAIL_CALL_CNT, 0, 0x2);
/*
* prog = array->ptrs[index];
* if (prog == NULL)
* goto out;
*/
/* sllg %r1,%b3,3: %r1 = index * 8 */
EMIT6_DISP_LH(0xeb000000, 0x000d, REG_1, BPF_REG_3, REG_0, 3);
/* lg %r1,prog(%b2,%r1) */
EMIT6_DISP_LH(0xe3000000, 0x0004, REG_1, BPF_REG_2,
REG_1, offsetof(struct bpf_array, ptrs));
/* clgij %r1,0,0x8,label0 */
EMIT6_PCREL_IMM_LABEL(0xec000000, 0x007d, REG_1, 0, 0, 0x8);
/*
* Restore registers before calling function
*/
save_restore_regs(jit, REGS_RESTORE);
/*
* goto *(prog->bpf_func + tail_call_start);
*/
/* lg %r1,bpf_func(%r1) */
EMIT6_DISP_LH(0xe3000000, 0x0004, REG_1, REG_1, REG_0,
offsetof(struct bpf_prog, bpf_func));
/* bc 0xf,tail_call_start(%r1) */
_EMIT4(0x47f01000 + jit->tail_call_start);
/* out: */
jit->labels[0] = jit->prg;
break;
case BPF_JMP | BPF_EXIT: /* return b0 */
last = (i == fp->len - 1) ? 1 : 0;
if (last && !(jit->seen & SEEN_RET0))
break;
/* j <exit> */
EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
break;
/*
* Branch relative (number of skipped instructions) to offset on
* condition.
*
* Condition code to mask mapping:
*
* CC | Description | Mask
* ------------------------------
* 0 | Operands equal | 8
* 1 | First operand low | 4
* 2 | First operand high | 2
* 3 | Unused | 1
*
* For s390x relative branches: ip = ip + off_bytes
* For BPF relative branches: insn = insn + off_insns + 1
*
* For example for s390x with offset 0 we jump to the branch
* instruction itself (loop) and for BPF with offset 0 we
* branch to the instruction behind the branch.
*/
case BPF_JMP | BPF_JA: /* if (true) */
mask = 0xf000; /* j */
goto branch_oc;
case BPF_JMP | BPF_JSGT | BPF_K: /* ((s64) dst > (s64) imm) */
mask = 0x2000; /* jh */
goto branch_ks;
case BPF_JMP | BPF_JSGE | BPF_K: /* ((s64) dst >= (s64) imm) */
mask = 0xa000; /* jhe */
goto branch_ks;
case BPF_JMP | BPF_JGT | BPF_K: /* (dst_reg > imm) */
mask = 0x2000; /* jh */
goto branch_ku;
case BPF_JMP | BPF_JGE | BPF_K: /* (dst_reg >= imm) */
mask = 0xa000; /* jhe */
goto branch_ku;
case BPF_JMP | BPF_JNE | BPF_K: /* (dst_reg != imm) */
mask = 0x7000; /* jne */
goto branch_ku;
case BPF_JMP | BPF_JEQ | BPF_K: /* (dst_reg == imm) */
mask = 0x8000; /* je */
goto branch_ku;
case BPF_JMP | BPF_JSET | BPF_K: /* (dst_reg & imm) */
mask = 0x7000; /* jnz */
/* lgfi %w1,imm (load sign extend imm) */
EMIT6_IMM(0xc0010000, REG_W1, imm);
/* ngr %w1,%dst */
EMIT4(0xb9800000, REG_W1, dst_reg);
goto branch_oc;
case BPF_JMP | BPF_JSGT | BPF_X: /* ((s64) dst > (s64) src) */
mask = 0x2000; /* jh */
goto branch_xs;
case BPF_JMP | BPF_JSGE | BPF_X: /* ((s64) dst >= (s64) src) */
mask = 0xa000; /* jhe */
goto branch_xs;
case BPF_JMP | BPF_JGT | BPF_X: /* (dst > src) */
mask = 0x2000; /* jh */
goto branch_xu;
case BPF_JMP | BPF_JGE | BPF_X: /* (dst >= src) */
mask = 0xa000; /* jhe */
goto branch_xu;
case BPF_JMP | BPF_JNE | BPF_X: /* (dst != src) */
mask = 0x7000; /* jne */
goto branch_xu;
case BPF_JMP | BPF_JEQ | BPF_X: /* (dst == src) */
mask = 0x8000; /* je */
goto branch_xu;
case BPF_JMP | BPF_JSET | BPF_X: /* (dst & src) */
mask = 0x7000; /* jnz */
/* ngrk %w1,%dst,%src */
EMIT4_RRF(0xb9e40000, REG_W1, dst_reg, src_reg);
goto branch_oc;
branch_ks:
/* lgfi %w1,imm (load sign extend imm) */
EMIT6_IMM(0xc0010000, REG_W1, imm);
/* cgrj %dst,%w1,mask,off */
EMIT6_PCREL(0xec000000, 0x0064, dst_reg, REG_W1, i, off, mask);
break;
branch_ku:
/* lgfi %w1,imm (load sign extend imm) */
EMIT6_IMM(0xc0010000, REG_W1, imm);
/* clgrj %dst,%w1,mask,off */
EMIT6_PCREL(0xec000000, 0x0065, dst_reg, REG_W1, i, off, mask);
break;
branch_xs:
/* cgrj %dst,%src,mask,off */
EMIT6_PCREL(0xec000000, 0x0064, dst_reg, src_reg, i, off, mask);
break;
branch_xu:
/* clgrj %dst,%src,mask,off */
EMIT6_PCREL(0xec000000, 0x0065, dst_reg, src_reg, i, off, mask);
break;
branch_oc:
/* brc mask,jmp_off (branch instruction needs 4 bytes) */
jmp_off = addrs[i + off + 1] - (addrs[i + 1] - 4);
EMIT4_PCREL(0xa7040000 | mask << 8, jmp_off);
break;
/*
* BPF_LD
*/
case BPF_LD | BPF_ABS | BPF_B: /* b0 = *(u8 *) (skb->data+imm) */
case BPF_LD | BPF_IND | BPF_B: /* b0 = *(u8 *) (skb->data+imm+src) */
if ((BPF_MODE(insn->code) == BPF_ABS) && (imm >= 0))
func_addr = __pa(sk_load_byte_pos);
else
func_addr = __pa(sk_load_byte);
goto call_fn;
case BPF_LD | BPF_ABS | BPF_H: /* b0 = *(u16 *) (skb->data+imm) */
case BPF_LD | BPF_IND | BPF_H: /* b0 = *(u16 *) (skb->data+imm+src) */
if ((BPF_MODE(insn->code) == BPF_ABS) && (imm >= 0))
func_addr = __pa(sk_load_half_pos);
else
func_addr = __pa(sk_load_half);
goto call_fn;
case BPF_LD | BPF_ABS | BPF_W: /* b0 = *(u32 *) (skb->data+imm) */
case BPF_LD | BPF_IND | BPF_W: /* b0 = *(u32 *) (skb->data+imm+src) */
if ((BPF_MODE(insn->code) == BPF_ABS) && (imm >= 0))
func_addr = __pa(sk_load_word_pos);
else
func_addr = __pa(sk_load_word);
goto call_fn;
call_fn:
jit->seen |= SEEN_SKB | SEEN_RET0 | SEEN_FUNC;
REG_SET_SEEN(REG_14); /* Return address of possible func call */
/*
* Implicit input:
* BPF_REG_6 (R7) : skb pointer
* REG_SKB_DATA (R12): skb data pointer
*
* Calculated input:
* BPF_REG_2 (R3) : offset of byte(s) to fetch in skb
* BPF_REG_5 (R6) : return address
*
* Output:
* BPF_REG_0 (R14): data read from skb
*
* Scratch registers (BPF_REG_1-5)
*/
/* Call function: llilf %w1,func_addr */
EMIT6_IMM(0xc00f0000, REG_W1, func_addr);
/* Offset: lgfi %b2,imm */
EMIT6_IMM(0xc0010000, BPF_REG_2, imm);
if (BPF_MODE(insn->code) == BPF_IND)
/* agfr %b2,%src (%src is s32 here) */
EMIT4(0xb9180000, BPF_REG_2, src_reg);
/* basr %b5,%w1 (%b5 is call saved) */
EMIT2(0x0d00, BPF_REG_5, REG_W1);
/*
* Note: For fast access we jump directly after the
* jnz instruction from bpf_jit.S
*/
/* jnz <ret0> */
EMIT4_PCREL(0xa7740000, jit->ret0_ip - jit->prg);
break;
default: /* too complex, give up */
pr_err("Unknown opcode %02x\n", insn->code);
return -1;
}
return insn_count;
}
/*
* Compile eBPF program into s390x code
*/
static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp)
{
int i, insn_count;
jit->lit = jit->lit_start;
jit->prg = 0;
bpf_jit_prologue(jit, bpf_prog_was_classic(fp));
for (i = 0; i < fp->len; i += insn_count) {
insn_count = bpf_jit_insn(jit, fp, i);
if (insn_count < 0)
return -1;
jit->addrs[i + 1] = jit->prg; /* Next instruction address */
}
bpf_jit_epilogue(jit);
jit->lit_start = jit->prg;
jit->size = jit->lit;
jit->size_prg = jit->prg;
return 0;
}
/*
* Classic BPF function stub. BPF programs will be converted into
* eBPF and then bpf_int_jit_compile() will be called.
*/
void bpf_jit_compile(struct bpf_prog *fp)
{
}
/*
* Compile eBPF program "fp"
*/
void bpf_int_jit_compile(struct bpf_prog *fp)
{
struct bpf_binary_header *header;
struct bpf_jit jit;
int pass;
if (!bpf_jit_enable)
return;
memset(&jit, 0, sizeof(jit));
jit.addrs = kcalloc(fp->len + 1, sizeof(*jit.addrs), GFP_KERNEL);
if (jit.addrs == NULL)
return;
/*
* Three initial passes:
* - 1/2: Determine clobbered registers
* - 3: Calculate program size and addrs arrray
*/
for (pass = 1; pass <= 3; pass++) {
if (bpf_jit_prog(&jit, fp))
goto free_addrs;
}
/*
* Final pass: Allocate and generate program
*/
if (jit.size >= BPF_SIZE_MAX)
goto free_addrs;
header = bpf_jit_binary_alloc(jit.size, &jit.prg_buf, 2, jit_fill_hole);
if (!header)
goto free_addrs;
if (bpf_jit_prog(&jit, fp))
goto free_addrs;
if (bpf_jit_enable > 1) {
bpf_jit_dump(fp->len, jit.size, pass, jit.prg_buf);
if (jit.prg_buf)
print_fn_code(jit.prg_buf, jit.size_prg);
}
if (jit.prg_buf) {
set_memory_ro((unsigned long)header, header->pages);
fp->bpf_func = (void *) jit.prg_buf;
fp->jited = 1;
}
free_addrs:
kfree(jit.addrs);
}
/*
* Free eBPF program
*/
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);
}