arch/s390/net/bpf_jit_comp.c - kernel/msm-4.9 - Gitiles

 /*
  * BPF Jit compiler for s390.
  *
  * Copyright IBM Corp. 2012
  *
  * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
  */
 #include <linux/moduleloader.h>
 #include <linux/netdevice.h>
 #include <linux/if_vlan.h>
 #include <linux/filter.h>
 #include <asm/cacheflush.h>
 #include <asm/processor.h>
 #include <asm/facility.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_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);
 		/* ahi %r15,<offset> */
 		EMIT4_IMM(0xa7fa0000, (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);
 }

 /*
  * 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_S_LD_W_ABS:
 	case BPF_S_LD_H_ABS:
 	case BPF_S_LD_B_ABS:
 	case BPF_S_LD_W_LEN:
 	case BPF_S_LD_W_IND:
 	case BPF_S_LD_H_IND:
 	case BPF_S_LD_B_IND:
 	case BPF_S_LDX_B_MSH:
 	case BPF_S_LD_IMM:
 	case BPF_S_LD_MEM:
 	case BPF_S_MISC_TXA:
 	case BPF_S_ANC_PROTOCOL:
 	case BPF_S_ANC_PKTTYPE:
 	case BPF_S_ANC_IFINDEX:
 	case BPF_S_ANC_MARK:
 	case BPF_S_ANC_QUEUE:
 	case BPF_S_ANC_HATYPE:
 	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_RET_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;

 	K = filter->k;
 	switch (filter->code) {
 	case BPF_S_ALU_ADD_X: /* A += X */
 		jit->seen |= SEEN_XREG;
 		/* ar %r5,%r12 */
 		EMIT2(0x1a5c);
 		break;
 	case BPF_S_ALU_ADD_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_S_ALU_SUB_X: /* A -= X */
 		jit->seen |= SEEN_XREG;
 		/* sr %r5,%r12 */
 		EMIT2(0x1b5c);
 		break;
 	case BPF_S_ALU_SUB_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_S_ALU_MUL_X: /* A *= X */
 		jit->seen |= SEEN_XREG;
 		/* msr %r5,%r12 */
 		EMIT4(0xb252005c);
 		break;
 	case BPF_S_ALU_MUL_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_S_ALU_DIV_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);
 		/* dr %r4,%r12 */
 		EMIT2(0x1d4c);
 		break;
 	case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K) */
 		/* m %r4,<d(K)>(%r13) */
 		EMIT4_DISP(0x5c40d000, EMIT_CONST(K));
 		/* lr %r5,%r4 */
 		EMIT2(0x1854);
 		break;
 	case BPF_S_ALU_MOD_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);
 		/* dr %r4,%r12 */
 		EMIT2(0x1d4c);
 		/* lr %r5,%r4 */
 		EMIT2(0x1854);
 		break;
 	case BPF_S_ALU_MOD_K: /* A %= K */
 		/* lhi %r4,0 */
 		EMIT4(0xa7480000);
 		/* d %r4,<d(K)>(%r13) */
 		EMIT4_DISP(0x5d40d000, EMIT_CONST(K));
 		/* lr %r5,%r4 */
 		EMIT2(0x1854);
 		break;
 	case BPF_S_ALU_AND_X: /* A &= X */
 		jit->seen |= SEEN_XREG;
 		/* nr %r5,%r12 */
 		EMIT2(0x145c);
 		break;
 	case BPF_S_ALU_AND_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_S_ALU_OR_X: /* A |= X */
 		jit->seen |= SEEN_XREG;
 		/* or %r5,%r12 */
 		EMIT2(0x165c);
 		break;
 	case BPF_S_ALU_OR_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_S_ANC_ALU_XOR_X: /* A ^= X; */
 	case BPF_S_ALU_XOR_X:
 		jit->seen |= SEEN_XREG;
 		/* xr %r5,%r12 */
 		EMIT2(0x175c);
 		break;
 	case BPF_S_ALU_XOR_K: /* A ^= K */
 		if (!K)
 			break;
 		/* x %r5,<d(K)>(%r13) */
 		EMIT4_DISP(0x5750d000, EMIT_CONST(K));
 		break;
 	case BPF_S_ALU_LSH_X: /* A <<= X; */
 		jit->seen |= SEEN_XREG;
 		/* sll %r5,0(%r12) */
 		EMIT4(0x8950c000);
 		break;
 	case BPF_S_ALU_LSH_K: /* A <<= K */
 		if (K == 0)
 			break;
 		/* sll %r5,K */
 		EMIT4_DISP(0x89500000, K);
 		break;
 	case BPF_S_ALU_RSH_X: /* A >>= X; */
 		jit->seen |= SEEN_XREG;
 		/* srl %r5,0(%r12) */
 		EMIT4(0x8850c000);
 		break;
 	case BPF_S_ALU_RSH_K: /* A >>= K; */
 		if (K == 0)
 			break;
 		/* srl %r5,K */
 		EMIT4_DISP(0x88500000, K);
 		break;
 	case BPF_S_ALU_NEG: /* A = -A */
 		/* lnr %r5,%r5 */
 		EMIT2(0x1155);
 		break;
 	case BPF_S_JMP_JA: /* ip += K */
 		offset = addrs[i + K] + jit->start - jit->prg;
 		EMIT4_PCREL(0xa7f40000, offset);
 		break;
 	case BPF_S_JMP_JGT_K: /* ip += (A > K) ? jt : jf */
 		mask = 0x200000; /* jh */
 		goto kbranch;
 	case BPF_S_JMP_JGE_K: /* ip += (A >= K) ? jt : jf */
 		mask = 0xa00000; /* jhe */
 		goto kbranch;
 	case BPF_S_JMP_JEQ_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_S_JMP_JSET_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_S_JMP_JGT_X: /* ip += (A > X) ? jt : jf */
 		mask = 0x200000; /* jh */
 		goto xbranch;
 	case BPF_S_JMP_JGE_X: /* ip += (A >= X) ? jt : jf */
 		mask = 0xa00000; /* jhe */
 		goto xbranch;
 	case BPF_S_JMP_JEQ_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_S_JMP_JSET_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_S_LD_W_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_S_LD_H_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_S_LD_B_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_S_LD_W_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_S_LD_H_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_S_LD_B_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_S_LDX_B_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_S_LD_W_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_S_LDX_W_LEN: /* X = skb->len; */
 		jit->seen |= SEEN_XREG;
 		/* l %r12,<d(len)>(%r2) */
 		EMIT4_DISP(0x58c02000, offsetof(struct sk_buff, len));
 		break;
 	case BPF_S_LD_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_S_LDX_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_S_LD_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_S_LDX_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_S_MISC_TAX: /* X = A */
 		jit->seen |= SEEN_XREG;
 		/* lr %r12,%r5 */
 		EMIT2(0x18c5);
 		break;
 	case BPF_S_MISC_TXA: /* A = X */
 		jit->seen |= SEEN_XREG;
 		/* lr %r5,%r12 */
 		EMIT2(0x185c);
 		break;
 	case BPF_S_RET_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_S_RET_A:
 		/* llgfr %r2,%r5 */
 		EMIT4(0xb9160025);
 		/* j <exit> */
 		EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
 		break;
 	case BPF_S_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_S_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_S_ANC_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_S_ANC_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_S_ANC_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_S_ANC_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_S_ANC_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_S_ANC_RXHASH: /* A = skb->rxhash */
 		BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
 		/* l %r5,<d(rxhash)>(%r2) */
 		EMIT4_DISP(0x58502000, offsetof(struct sk_buff, rxhash));
 		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);
 		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 (filter->code == BPF_S_ANC_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_S_ANC_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 sk_filter *fp)
 {
 	unsigned long size, prg_len, lit_len;
 	struct bpf_jit jit, cjit;
 	unsigned int *addrs;
 	int pass, i;

 	if (!bpf_jit_enable)
 		return;
 	addrs = kmalloc(fp->len * sizeof(*addrs), GFP_KERNEL);
 	if (addrs == NULL)
 		return;
 	memset(addrs, 0, fp->len * sizeof(*addrs));
 	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 = max_t(unsigned long, prg_len + lit_len,
 				     sizeof(struct work_struct));
 			if (size >= BPF_SIZE_MAX)
 				goto out;
 			jit.start = module_alloc(size);
 			if (!jit.start)
 				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) {
 		pr_err("flen=%d proglen=%lu pass=%d image=%p\n",
 		       fp->len, jit.end - jit.start, pass, jit.start);
 		if (jit.start) {
 			printk(KERN_ERR "JIT code:\n");
 			print_fn_code(jit.start, jit.mid - jit.start);
 			print_hex_dump(KERN_ERR, "JIT literals:\n",
 				       DUMP_PREFIX_ADDRESS, 16, 1,
 				       jit.mid, jit.end - jit.mid, false);
 		}
 	}
 	if (jit.start)
 		fp->bpf_func = (void *) jit.start;
 out:
 	kfree(addrs);
 }

 static void jit_free_defer(struct work_struct *arg)
 {
 	module_free(NULL, arg);
 }

 /* run from softirq, we must use a work_struct to call
  * module_free() from process context
  */
 void bpf_jit_free(struct sk_filter *fp)
 {
 	struct work_struct *work;

 	if (fp->bpf_func == sk_run_filter)
 		return;
 	work = (struct work_struct *)fp->bpf_func;
 	INIT_WORK(work, jit_free_defer);
 	schedule_work(work);
 }
	/*
	* BPF Jit compiler for s390.
	*
	* Copyright IBM Corp. 2012
	*
	* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
	*/
	#include <linux/moduleloader.h>
	#include <linux/netdevice.h>
	#include <linux/if_vlan.h>
	#include <linux/filter.h>
	#include <asm/cacheflush.h>
	#include <asm/processor.h>
	#include <asm/facility.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_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);
	/* ahi %r15,<offset> */
	EMIT4_IMM(0xa7fa0000, (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);
	}

	/*
	* 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_S_LD_W_ABS:
	case BPF_S_LD_H_ABS:
	case BPF_S_LD_B_ABS:
	case BPF_S_LD_W_LEN:
	case BPF_S_LD_W_IND:
	case BPF_S_LD_H_IND:
	case BPF_S_LD_B_IND:
	case BPF_S_LDX_B_MSH:
	case BPF_S_LD_IMM:
	case BPF_S_LD_MEM:
	case BPF_S_MISC_TXA:
	case BPF_S_ANC_PROTOCOL:
	case BPF_S_ANC_PKTTYPE:
	case BPF_S_ANC_IFINDEX:
	case BPF_S_ANC_MARK:
	case BPF_S_ANC_QUEUE:
	case BPF_S_ANC_HATYPE:
	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_RET_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;

	K = filter->k;
	switch (filter->code) {
	case BPF_S_ALU_ADD_X: /* A += X */
	jit->seen \|= SEEN_XREG;
	/* ar %r5,%r12 */
	EMIT2(0x1a5c);
	break;
	case BPF_S_ALU_ADD_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_S_ALU_SUB_X: /* A -= X */
	jit->seen \|= SEEN_XREG;
	/* sr %r5,%r12 */
	EMIT2(0x1b5c);
	break;
	case BPF_S_ALU_SUB_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_S_ALU_MUL_X: /* A = X /
	jit->seen \|= SEEN_XREG;
	/* msr %r5,%r12 */
	EMIT4(0xb252005c);
	break;
	case BPF_S_ALU_MUL_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_S_ALU_DIV_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);
	/* dr %r4,%r12 */
	EMIT2(0x1d4c);
	break;
	case BPF_S_ALU_DIV_K: /* A = reciprocal_divide(A, K) */
	/* m %r4,<d(K)>(%r13) */
	EMIT4_DISP(0x5c40d000, EMIT_CONST(K));
	/* lr %r5,%r4 */
	EMIT2(0x1854);
	break;
	case BPF_S_ALU_MOD_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);
	/* dr %r4,%r12 */
	EMIT2(0x1d4c);
	/* lr %r5,%r4 */
	EMIT2(0x1854);
	break;
	case BPF_S_ALU_MOD_K: /* A %= K */
	/* lhi %r4,0 */
	EMIT4(0xa7480000);
	/* d %r4,<d(K)>(%r13) */
	EMIT4_DISP(0x5d40d000, EMIT_CONST(K));
	/* lr %r5,%r4 */
	EMIT2(0x1854);
	break;
	case BPF_S_ALU_AND_X: /* A &= X */
	jit->seen \|= SEEN_XREG;
	/* nr %r5,%r12 */
	EMIT2(0x145c);
	break;
	case BPF_S_ALU_AND_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_S_ALU_OR_X: /* A \|= X */
	jit->seen \|= SEEN_XREG;
	/* or %r5,%r12 */
	EMIT2(0x165c);
	break;
	case BPF_S_ALU_OR_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_S_ANC_ALU_XOR_X: /* A ^= X; */
	case BPF_S_ALU_XOR_X:
	jit->seen \|= SEEN_XREG;
	/* xr %r5,%r12 */
	EMIT2(0x175c);
	break;
	case BPF_S_ALU_XOR_K: /* A ^= K */
	if (!K)
	break;
	/* x %r5,<d(K)>(%r13) */
	EMIT4_DISP(0x5750d000, EMIT_CONST(K));
	break;
	case BPF_S_ALU_LSH_X: /* A <<= X; */
	jit->seen \|= SEEN_XREG;
	/* sll %r5,0(%r12) */
	EMIT4(0x8950c000);
	break;
	case BPF_S_ALU_LSH_K: /* A <<= K */
	if (K == 0)
	break;
	/* sll %r5,K */
	EMIT4_DISP(0x89500000, K);
	break;
	case BPF_S_ALU_RSH_X: /* A >>= X; */
	jit->seen \|= SEEN_XREG;
	/* srl %r5,0(%r12) */
	EMIT4(0x8850c000);
	break;
	case BPF_S_ALU_RSH_K: /* A >>= K; */
	if (K == 0)
	break;
	/* srl %r5,K */
	EMIT4_DISP(0x88500000, K);
	break;
	case BPF_S_ALU_NEG: /* A = -A */
	/* lnr %r5,%r5 */
	EMIT2(0x1155);
	break;
	case BPF_S_JMP_JA: /* ip += K */
	offset = addrs[i + K] + jit->start - jit->prg;
	EMIT4_PCREL(0xa7f40000, offset);
	break;
	case BPF_S_JMP_JGT_K: /* ip += (A > K) ? jt : jf */
	mask = 0x200000; /* jh */
	goto kbranch;
	case BPF_S_JMP_JGE_K: /* ip += (A >= K) ? jt : jf */
	mask = 0xa00000; /* jhe */
	goto kbranch;
	case BPF_S_JMP_JEQ_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_S_JMP_JSET_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_S_JMP_JGT_X: /* ip += (A > X) ? jt : jf */
	mask = 0x200000; /* jh */
	goto xbranch;
	case BPF_S_JMP_JGE_X: /* ip += (A >= X) ? jt : jf */
	mask = 0xa00000; /* jhe */
	goto xbranch;
	case BPF_S_JMP_JEQ_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_S_JMP_JSET_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_S_LD_W_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_S_LD_H_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_S_LD_B_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_S_LD_W_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_S_LD_H_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_S_LD_B_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_S_LDX_B_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_S_LD_W_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_S_LDX_W_LEN: /* X = skb->len; */
	jit->seen \|= SEEN_XREG;
	/* l %r12,<d(len)>(%r2) */
	EMIT4_DISP(0x58c02000, offsetof(struct sk_buff, len));
	break;
	case BPF_S_LD_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_S_LDX_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_S_LD_MEM: /* A = mem[K] */
	jit->seen \|= SEEN_MEM;
	/* l %r5,<K>(%r15) */
	EMIT4_DISP(0x5850f000,
	(jit->seen & SEEN_DATAREF) ? 160 + K4 : K4);
	break;
	case BPF_S_LDX_MEM: /* X = mem[K] */
	jit->seen \|= SEEN_XREG \| SEEN_MEM;
	/* l %r12,<K>(%r15) */
	EMIT4_DISP(0x58c0f000,
	(jit->seen & SEEN_DATAREF) ? 160 + K4 : K4);
	break;
	case BPF_S_MISC_TAX: /* X = A */
	jit->seen \|= SEEN_XREG;
	/* lr %r12,%r5 */
	EMIT2(0x18c5);
	break;
	case BPF_S_MISC_TXA: /* A = X */
	jit->seen \|= SEEN_XREG;
	/* lr %r5,%r12 */
	EMIT2(0x185c);
	break;
	case BPF_S_RET_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_S_RET_A:
	/* llgfr %r2,%r5 */
	EMIT4(0xb9160025);
	/* j <exit> */
	EMIT4_PCREL(0xa7f40000, jit->exit_ip - jit->prg);
	break;
	case BPF_S_ST: /* mem[K] = A */
	jit->seen \|= SEEN_MEM;
	/* st %r5,<K>(%r15) */
	EMIT4_DISP(0x5050f000,
	(jit->seen & SEEN_DATAREF) ? 160 + K4 : K4);
	break;
	case BPF_S_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 + K4 : K4);
	break;
	case BPF_S_ANC_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_S_ANC_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_S_ANC_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_S_ANC_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_S_ANC_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_S_ANC_RXHASH: /* A = skb->rxhash */
	BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, rxhash) != 4);
	/* l %r5,<d(rxhash)>(%r2) */
	EMIT4_DISP(0x58502000, offsetof(struct sk_buff, rxhash));
	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);
	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 (filter->code == BPF_S_ANC_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_S_ANC_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 sk_filter *fp)
	{
	unsigned long size, prg_len, lit_len;
	struct bpf_jit jit, cjit;
	unsigned int *addrs;
	int pass, i;

	if (!bpf_jit_enable)
	return;
	addrs = kmalloc(fp->len * sizeof(*addrs), GFP_KERNEL);
	if (addrs == NULL)
	return;
	memset(addrs, 0, fp->len * sizeof(*addrs));
	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 = max_t(unsigned long, prg_len + lit_len,
	sizeof(struct work_struct));
	if (size >= BPF_SIZE_MAX)
	goto out;
	jit.start = module_alloc(size);
	if (!jit.start)
	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) {
	pr_err("flen=%d proglen=%lu pass=%d image=%p\n",
	fp->len, jit.end - jit.start, pass, jit.start);
	if (jit.start) {
	printk(KERN_ERR "JIT code:\n");
	print_fn_code(jit.start, jit.mid - jit.start);
	print_hex_dump(KERN_ERR, "JIT literals:\n",
	DUMP_PREFIX_ADDRESS, 16, 1,
	jit.mid, jit.end - jit.mid, false);
	}
	}
	if (jit.start)
	fp->bpf_func = (void *) jit.start;
	out:
	kfree(addrs);
	}

	static void jit_free_defer(struct work_struct *arg)
	{
	module_free(NULL, arg);
	}

	/* run from softirq, we must use a work_struct to call
	* module_free() from process context
	*/
	void bpf_jit_free(struct sk_filter *fp)
	{
	struct work_struct *work;

	if (fp->bpf_func == sk_run_filter)
	return;
	work = (struct work_struct *)fp->bpf_func;
	INIT_WORK(work, jit_free_defer);
	schedule_work(work);
	}