2 * Just-In-Time compiler for BPF filters on MIPS
4 * Copyright (c) 2014 Imagination Technologies Ltd.
5 * Author: Markos Chandras <markos.chandras@imgtec.com>
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; version 2 of the License.
12 #include <linux/bitops.h>
13 #include <linux/compiler.h>
14 #include <linux/errno.h>
15 #include <linux/filter.h>
16 #include <linux/if_vlan.h>
17 #include <linux/kconfig.h>
18 #include <linux/moduleloader.h>
19 #include <linux/netdevice.h>
20 #include <linux/string.h>
21 #include <linux/slab.h>
22 #include <linux/types.h>
24 #include <asm/bitops.h>
25 #include <asm/cacheflush.h>
26 #include <asm/cpu-features.h>
32 * r_skb_hl SKB header length
33 * r_data SKB data pointer
39 * r_skb_len SKB length
41 * On entry (*bpf_func)(*skb, *filter)
42 * a0 = MIPS_R_A0 = skb;
43 * a1 = MIPS_R_A1 = filter;
55 * saved reg 0 <-- r_sp
60 * <--------------------- len ------------------------>
61 * <--skb-len(r_skb_hl)-->< ----- skb->data_len ------>
62 * ----------------------------------------------------
64 * ----------------------------------------------------
67 #define ptr typeof(unsigned long)
69 #define SCRATCH_OFF(k) (4 * (k))
72 #define SEEN_CALL (1 << BPF_MEMWORDS)
73 #define SEEN_SREG_SFT (BPF_MEMWORDS + 1)
74 #define SEEN_SREG_BASE (1 << SEEN_SREG_SFT)
75 #define SEEN_SREG(x) (SEEN_SREG_BASE << (x))
76 #define SEEN_OFF SEEN_SREG(2)
77 #define SEEN_A SEEN_SREG(3)
78 #define SEEN_X SEEN_SREG(4)
79 #define SEEN_SKB SEEN_SREG(5)
80 #define SEEN_MEM SEEN_SREG(6)
81 /* SEEN_SK_DATA also implies skb_hl an skb_len */
82 #define SEEN_SKB_DATA (SEEN_SREG(7) | SEEN_SREG(1) | SEEN_SREG(0))
84 /* Arguments used by JIT */
85 #define ARGS_USED_BY_JIT 2 /* only applicable to 64-bit */
87 #define SBIT(x) (1 << (x)) /* Signed version of BIT() */
90 * struct jit_ctx - JIT context
92 * @prologue_bytes: Number of bytes for prologue
93 * @idx: Instruction index
95 * @offsets: Instruction offsets
96 * @target: Memory location for the compiled filter
99 const struct bpf_prog
*skf
;
100 unsigned int prologue_bytes
;
108 static inline int optimize_div(u32
*k
)
110 /* power of 2 divides can be implemented with right shift */
111 if (!(*k
& (*k
-1))) {
119 static inline void emit_jit_reg_move(ptr dst
, ptr src
, struct jit_ctx
*ctx
);
121 /* Simply emit the instruction if the JIT memory space has been allocated */
122 #define emit_instr(ctx, func, ...) \
124 if ((ctx)->target != NULL) { \
125 u32 *p = &(ctx)->target[ctx->idx]; \
126 uasm_i_##func(&p, ##__VA_ARGS__); \
132 * Similar to emit_instr but it must be used when we need to emit
133 * 32-bit or 64-bit instructions
135 #define emit_long_instr(ctx, func, ...) \
137 if ((ctx)->target != NULL) { \
138 u32 *p = &(ctx)->target[ctx->idx]; \
139 UASM_i_##func(&p, ##__VA_ARGS__); \
144 /* Determine if immediate is within the 16-bit signed range */
145 static inline bool is_range16(s32 imm
)
147 return !(imm
>= SBIT(15) || imm
< -SBIT(15));
150 static inline void emit_addu(unsigned int dst
, unsigned int src1
,
151 unsigned int src2
, struct jit_ctx
*ctx
)
153 emit_instr(ctx
, addu
, dst
, src1
, src2
);
156 static inline void emit_nop(struct jit_ctx
*ctx
)
158 emit_instr(ctx
, nop
);
161 /* Load a u32 immediate to a register */
162 static inline void emit_load_imm(unsigned int dst
, u32 imm
, struct jit_ctx
*ctx
)
164 if (ctx
->target
!= NULL
) {
165 /* addiu can only handle s16 */
166 if (!is_range16(imm
)) {
167 u32
*p
= &ctx
->target
[ctx
->idx
];
168 uasm_i_lui(&p
, r_tmp_imm
, (s32
)imm
>> 16);
169 p
= &ctx
->target
[ctx
->idx
+ 1];
170 uasm_i_ori(&p
, dst
, r_tmp_imm
, imm
& 0xffff);
172 u32
*p
= &ctx
->target
[ctx
->idx
];
173 uasm_i_addiu(&p
, dst
, r_zero
, imm
);
178 if (!is_range16(imm
))
182 static inline void emit_or(unsigned int dst
, unsigned int src1
,
183 unsigned int src2
, struct jit_ctx
*ctx
)
185 emit_instr(ctx
, or, dst
, src1
, src2
);
188 static inline void emit_ori(unsigned int dst
, unsigned src
, u32 imm
,
191 if (imm
>= BIT(16)) {
192 emit_load_imm(r_tmp
, imm
, ctx
);
193 emit_or(dst
, src
, r_tmp
, ctx
);
195 emit_instr(ctx
, ori
, dst
, src
, imm
);
199 static inline void emit_daddiu(unsigned int dst
, unsigned int src
,
200 int imm
, struct jit_ctx
*ctx
)
203 * Only used for stack, so the imm is relatively small
204 * and it fits in 15-bits
206 emit_instr(ctx
, daddiu
, dst
, src
, imm
);
209 static inline void emit_addiu(unsigned int dst
, unsigned int src
,
210 u32 imm
, struct jit_ctx
*ctx
)
212 if (!is_range16(imm
)) {
213 emit_load_imm(r_tmp
, imm
, ctx
);
214 emit_addu(dst
, r_tmp
, src
, ctx
);
216 emit_instr(ctx
, addiu
, dst
, src
, imm
);
220 static inline void emit_and(unsigned int dst
, unsigned int src1
,
221 unsigned int src2
, struct jit_ctx
*ctx
)
223 emit_instr(ctx
, and, dst
, src1
, src2
);
226 static inline void emit_andi(unsigned int dst
, unsigned int src
,
227 u32 imm
, struct jit_ctx
*ctx
)
229 /* If imm does not fit in u16 then load it to register */
230 if (imm
>= BIT(16)) {
231 emit_load_imm(r_tmp
, imm
, ctx
);
232 emit_and(dst
, src
, r_tmp
, ctx
);
234 emit_instr(ctx
, andi
, dst
, src
, imm
);
238 static inline void emit_xor(unsigned int dst
, unsigned int src1
,
239 unsigned int src2
, struct jit_ctx
*ctx
)
241 emit_instr(ctx
, xor, dst
, src1
, src2
);
244 static inline void emit_xori(ptr dst
, ptr src
, u32 imm
, struct jit_ctx
*ctx
)
246 /* If imm does not fit in u16 then load it to register */
247 if (imm
>= BIT(16)) {
248 emit_load_imm(r_tmp
, imm
, ctx
);
249 emit_xor(dst
, src
, r_tmp
, ctx
);
251 emit_instr(ctx
, xori
, dst
, src
, imm
);
255 static inline void emit_stack_offset(int offset
, struct jit_ctx
*ctx
)
257 emit_long_instr(ctx
, ADDIU
, r_sp
, r_sp
, offset
);
260 static inline void emit_subu(unsigned int dst
, unsigned int src1
,
261 unsigned int src2
, struct jit_ctx
*ctx
)
263 emit_instr(ctx
, subu
, dst
, src1
, src2
);
266 static inline void emit_neg(unsigned int reg
, struct jit_ctx
*ctx
)
268 emit_subu(reg
, r_zero
, reg
, ctx
);
271 static inline void emit_sllv(unsigned int dst
, unsigned int src
,
272 unsigned int sa
, struct jit_ctx
*ctx
)
274 emit_instr(ctx
, sllv
, dst
, src
, sa
);
277 static inline void emit_sll(unsigned int dst
, unsigned int src
,
278 unsigned int sa
, struct jit_ctx
*ctx
)
280 /* sa is 5-bits long */
282 /* Shifting >= 32 results in zero */
283 emit_jit_reg_move(dst
, r_zero
, ctx
);
285 emit_instr(ctx
, sll
, dst
, src
, sa
);
288 static inline void emit_srlv(unsigned int dst
, unsigned int src
,
289 unsigned int sa
, struct jit_ctx
*ctx
)
291 emit_instr(ctx
, srlv
, dst
, src
, sa
);
294 static inline void emit_srl(unsigned int dst
, unsigned int src
,
295 unsigned int sa
, struct jit_ctx
*ctx
)
297 /* sa is 5-bits long */
299 /* Shifting >= 32 results in zero */
300 emit_jit_reg_move(dst
, r_zero
, ctx
);
302 emit_instr(ctx
, srl
, dst
, src
, sa
);
305 static inline void emit_slt(unsigned int dst
, unsigned int src1
,
306 unsigned int src2
, struct jit_ctx
*ctx
)
308 emit_instr(ctx
, slt
, dst
, src1
, src2
);
311 static inline void emit_sltu(unsigned int dst
, unsigned int src1
,
312 unsigned int src2
, struct jit_ctx
*ctx
)
314 emit_instr(ctx
, sltu
, dst
, src1
, src2
);
317 static inline void emit_sltiu(unsigned dst
, unsigned int src
,
318 unsigned int imm
, struct jit_ctx
*ctx
)
320 /* 16 bit immediate */
321 if (!is_range16((s32
)imm
)) {
322 emit_load_imm(r_tmp
, imm
, ctx
);
323 emit_sltu(dst
, src
, r_tmp
, ctx
);
325 emit_instr(ctx
, sltiu
, dst
, src
, imm
);
330 /* Store register on the stack */
331 static inline void emit_store_stack_reg(ptr reg
, ptr base
,
335 emit_long_instr(ctx
, SW
, reg
, offset
, base
);
338 static inline void emit_store(ptr reg
, ptr base
, unsigned int offset
,
341 emit_instr(ctx
, sw
, reg
, offset
, base
);
344 static inline void emit_load_stack_reg(ptr reg
, ptr base
,
348 emit_long_instr(ctx
, LW
, reg
, offset
, base
);
351 static inline void emit_load(unsigned int reg
, unsigned int base
,
352 unsigned int offset
, struct jit_ctx
*ctx
)
354 emit_instr(ctx
, lw
, reg
, offset
, base
);
357 static inline void emit_load_byte(unsigned int reg
, unsigned int base
,
358 unsigned int offset
, struct jit_ctx
*ctx
)
360 emit_instr(ctx
, lb
, reg
, offset
, base
);
363 static inline void emit_half_load(unsigned int reg
, unsigned int base
,
364 unsigned int offset
, struct jit_ctx
*ctx
)
366 emit_instr(ctx
, lh
, reg
, offset
, base
);
369 static inline void emit_mul(unsigned int dst
, unsigned int src1
,
370 unsigned int src2
, struct jit_ctx
*ctx
)
372 emit_instr(ctx
, mul
, dst
, src1
, src2
);
375 static inline void emit_div(unsigned int dst
, unsigned int src
,
378 if (ctx
->target
!= NULL
) {
379 u32
*p
= &ctx
->target
[ctx
->idx
];
380 uasm_i_divu(&p
, dst
, src
);
381 p
= &ctx
->target
[ctx
->idx
+ 1];
382 uasm_i_mflo(&p
, dst
);
384 ctx
->idx
+= 2; /* 2 insts */
387 static inline void emit_mod(unsigned int dst
, unsigned int src
,
390 if (ctx
->target
!= NULL
) {
391 u32
*p
= &ctx
->target
[ctx
->idx
];
392 uasm_i_divu(&p
, dst
, src
);
393 p
= &ctx
->target
[ctx
->idx
+ 1];
394 uasm_i_mfhi(&p
, dst
);
396 ctx
->idx
+= 2; /* 2 insts */
399 static inline void emit_dsll(unsigned int dst
, unsigned int src
,
400 unsigned int sa
, struct jit_ctx
*ctx
)
402 emit_instr(ctx
, dsll
, dst
, src
, sa
);
405 static inline void emit_dsrl32(unsigned int dst
, unsigned int src
,
406 unsigned int sa
, struct jit_ctx
*ctx
)
408 emit_instr(ctx
, dsrl32
, dst
, src
, sa
);
411 static inline void emit_wsbh(unsigned int dst
, unsigned int src
,
414 emit_instr(ctx
, wsbh
, dst
, src
);
417 /* load pointer to register */
418 static inline void emit_load_ptr(unsigned int dst
, unsigned int src
,
419 int imm
, struct jit_ctx
*ctx
)
421 /* src contains the base addr of the 32/64-pointer */
422 emit_long_instr(ctx
, LW
, dst
, imm
, src
);
425 /* load a function pointer to register */
426 static inline void emit_load_func(unsigned int reg
, ptr imm
,
429 if (config_enabled(CONFIG_64BIT
)) {
430 /* At this point imm is always 64-bit */
431 emit_load_imm(r_tmp
, (u64
)imm
>> 32, ctx
);
432 emit_dsll(r_tmp_imm
, r_tmp
, 16, ctx
); /* left shift by 16 */
433 emit_ori(r_tmp
, r_tmp_imm
, (imm
>> 16) & 0xffff, ctx
);
434 emit_dsll(r_tmp_imm
, r_tmp
, 16, ctx
); /* left shift by 16 */
435 emit_ori(reg
, r_tmp_imm
, imm
& 0xffff, ctx
);
437 emit_load_imm(reg
, imm
, ctx
);
441 /* Move to real MIPS register */
442 static inline void emit_reg_move(ptr dst
, ptr src
, struct jit_ctx
*ctx
)
444 emit_long_instr(ctx
, ADDU
, dst
, src
, r_zero
);
447 /* Move to JIT (32-bit) register */
448 static inline void emit_jit_reg_move(ptr dst
, ptr src
, struct jit_ctx
*ctx
)
450 emit_addu(dst
, src
, r_zero
, ctx
);
453 /* Compute the immediate value for PC-relative branches. */
454 static inline u32
b_imm(unsigned int tgt
, struct jit_ctx
*ctx
)
456 if (ctx
->target
== NULL
)
460 * We want a pc-relative branch. We only do forward branches
461 * so tgt is always after pc. tgt is the instruction offset
462 * we want to jump to.
465 * I: target_offset <- sign_extend(offset)
466 * I+1: PC += target_offset (delay slot)
468 * ctx->idx currently points to the branch instruction
469 * but the offset is added to the delay slot so we need
472 return ctx
->offsets
[tgt
] -
473 (ctx
->idx
* 4 - ctx
->prologue_bytes
) - 4;
476 static inline void emit_bcond(int cond
, unsigned int reg1
, unsigned int reg2
,
477 unsigned int imm
, struct jit_ctx
*ctx
)
479 if (ctx
->target
!= NULL
) {
480 u32
*p
= &ctx
->target
[ctx
->idx
];
484 uasm_i_beq(&p
, reg1
, reg2
, imm
);
487 uasm_i_bne(&p
, reg1
, reg2
, imm
);
493 pr_warn("%s: Unhandled branch conditional: %d\n",
500 static inline void emit_b(unsigned int imm
, struct jit_ctx
*ctx
)
502 emit_bcond(MIPS_COND_ALL
, r_zero
, r_zero
, imm
, ctx
);
505 static inline void emit_jalr(unsigned int link
, unsigned int reg
,
508 emit_instr(ctx
, jalr
, link
, reg
);
511 static inline void emit_jr(unsigned int reg
, struct jit_ctx
*ctx
)
513 emit_instr(ctx
, jr
, reg
);
516 static inline u16
align_sp(unsigned int num
)
518 /* Double word alignment for 32-bit, quadword for 64-bit */
519 unsigned int align
= config_enabled(CONFIG_64BIT
) ? 16 : 8;
520 num
= (num
+ (align
- 1)) & -align
;
524 static bool is_load_to_a(u16 inst
)
527 case BPF_LD
| BPF_W
| BPF_LEN
:
528 case BPF_LD
| BPF_W
| BPF_ABS
:
529 case BPF_LD
| BPF_H
| BPF_ABS
:
530 case BPF_LD
| BPF_B
| BPF_ABS
:
537 static void save_bpf_jit_regs(struct jit_ctx
*ctx
, unsigned offset
)
539 int i
= 0, real_off
= 0;
540 u32 sflags
, tmp_flags
;
542 /* Adjust the stack pointer */
543 emit_stack_offset(-align_sp(offset
), ctx
);
545 tmp_flags
= sflags
= ctx
->flags
>> SEEN_SREG_SFT
;
546 /* sflags is essentially a bitmap */
548 if ((sflags
>> i
) & 0x1) {
549 emit_store_stack_reg(MIPS_R_S0
+ i
, r_sp
, real_off
,
557 /* save return address */
558 if (ctx
->flags
& SEEN_CALL
) {
559 emit_store_stack_reg(r_ra
, r_sp
, real_off
, ctx
);
563 /* Setup r_M leaving the alignment gap if necessary */
564 if (ctx
->flags
& SEEN_MEM
) {
565 if (real_off
% (SZREG
* 2))
567 emit_long_instr(ctx
, ADDIU
, r_M
, r_sp
, real_off
);
571 static void restore_bpf_jit_regs(struct jit_ctx
*ctx
,
575 u32 sflags
, tmp_flags
;
577 tmp_flags
= sflags
= ctx
->flags
>> SEEN_SREG_SFT
;
578 /* sflags is a bitmap */
581 if ((sflags
>> i
) & 0x1) {
582 emit_load_stack_reg(MIPS_R_S0
+ i
, r_sp
, real_off
,
590 /* restore return address */
591 if (ctx
->flags
& SEEN_CALL
)
592 emit_load_stack_reg(r_ra
, r_sp
, real_off
, ctx
);
594 /* Restore the sp and discard the scrach memory */
595 emit_stack_offset(align_sp(offset
), ctx
);
598 static unsigned int get_stack_depth(struct jit_ctx
*ctx
)
603 /* How may s* regs do we need to preserved? */
604 sp_off
+= hweight32(ctx
->flags
>> SEEN_SREG_SFT
) * SZREG
;
606 if (ctx
->flags
& SEEN_MEM
)
607 sp_off
+= 4 * BPF_MEMWORDS
; /* BPF_MEMWORDS are 32-bit */
609 if (ctx
->flags
& SEEN_CALL
)
610 sp_off
+= SZREG
; /* Space for our ra register */
615 static void build_prologue(struct jit_ctx
*ctx
)
617 u16 first_inst
= ctx
->skf
->insns
[0].code
;
620 /* Calculate the total offset for the stack pointer */
621 sp_off
= get_stack_depth(ctx
);
622 save_bpf_jit_regs(ctx
, sp_off
);
624 if (ctx
->flags
& SEEN_SKB
)
625 emit_reg_move(r_skb
, MIPS_R_A0
, ctx
);
627 if (ctx
->flags
& SEEN_SKB_DATA
) {
628 /* Load packet length */
629 emit_load(r_skb_len
, r_skb
, offsetof(struct sk_buff
, len
),
631 emit_load(r_tmp
, r_skb
, offsetof(struct sk_buff
, data_len
),
633 /* Load the data pointer */
634 emit_load_ptr(r_skb_data
, r_skb
,
635 offsetof(struct sk_buff
, data
), ctx
);
636 /* Load the header length */
637 emit_subu(r_skb_hl
, r_skb_len
, r_tmp
, ctx
);
640 if (ctx
->flags
& SEEN_X
)
641 emit_jit_reg_move(r_X
, r_zero
, ctx
);
643 /* Do not leak kernel data to userspace */
644 if ((first_inst
!= (BPF_RET
| BPF_K
)) && !(is_load_to_a(first_inst
)))
645 emit_jit_reg_move(r_A
, r_zero
, ctx
);
648 static void build_epilogue(struct jit_ctx
*ctx
)
652 /* Calculate the total offset for the stack pointer */
654 sp_off
= get_stack_depth(ctx
);
655 restore_bpf_jit_regs(ctx
, sp_off
);
662 #define CHOOSE_LOAD_FUNC(K, func) \
663 ((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative : func) : \
666 static int build_body(struct jit_ctx
*ctx
)
668 const struct bpf_prog
*prog
= ctx
->skf
;
669 const struct sock_filter
*inst
;
670 unsigned int i
, off
, condt
;
671 u32 k
, b_off __maybe_unused
;
672 u8 (*sk_load_func
)(unsigned long *skb
, int offset
);
674 for (i
= 0; i
< prog
->len
; i
++) {
677 inst
= &(prog
->insns
[i
]);
678 pr_debug("%s: code->0x%02x, jt->0x%x, jf->0x%x, k->0x%x\n",
679 __func__
, inst
->code
, inst
->jt
, inst
->jf
, inst
->k
);
681 code
= bpf_anc_helper(inst
);
683 if (ctx
->target
== NULL
)
684 ctx
->offsets
[i
] = ctx
->idx
* 4;
687 case BPF_LD
| BPF_IMM
:
688 /* A <- k ==> li r_A, k */
689 ctx
->flags
|= SEEN_A
;
690 emit_load_imm(r_A
, k
, ctx
);
692 case BPF_LD
| BPF_W
| BPF_LEN
:
693 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, len
) != 4);
694 /* A <- len ==> lw r_A, offset(skb) */
695 ctx
->flags
|= SEEN_SKB
| SEEN_A
;
696 off
= offsetof(struct sk_buff
, len
);
697 emit_load(r_A
, r_skb
, off
, ctx
);
699 case BPF_LD
| BPF_MEM
:
700 /* A <- M[k] ==> lw r_A, offset(M) */
701 ctx
->flags
|= SEEN_MEM
| SEEN_A
;
702 emit_load(r_A
, r_M
, SCRATCH_OFF(k
), ctx
);
704 case BPF_LD
| BPF_W
| BPF_ABS
:
706 sk_load_func
= CHOOSE_LOAD_FUNC(k
, sk_load_word
);
708 case BPF_LD
| BPF_H
| BPF_ABS
:
710 sk_load_func
= CHOOSE_LOAD_FUNC(k
, sk_load_half
);
712 case BPF_LD
| BPF_B
| BPF_ABS
:
714 sk_load_func
= CHOOSE_LOAD_FUNC(k
, sk_load_byte
);
716 emit_load_imm(r_off
, k
, ctx
);
718 ctx
->flags
|= SEEN_CALL
| SEEN_OFF
|
719 SEEN_SKB
| SEEN_A
| SEEN_SKB_DATA
;
721 emit_load_func(r_s0
, (ptr
)sk_load_func
, ctx
);
722 emit_reg_move(MIPS_R_A0
, r_skb
, ctx
);
723 emit_jalr(MIPS_R_RA
, r_s0
, ctx
);
724 /* Load second argument to delay slot */
725 emit_reg_move(MIPS_R_A1
, r_off
, ctx
);
726 /* Check the error value */
727 emit_bcond(MIPS_COND_EQ
, r_ret
, 0, b_imm(i
+ 1, ctx
),
729 /* Load return register on DS for failures */
730 emit_reg_move(r_ret
, r_zero
, ctx
);
731 /* Return with error */
732 emit_b(b_imm(prog
->len
, ctx
), ctx
);
735 case BPF_LD
| BPF_W
| BPF_IND
:
736 /* A <- P[X + k:4] */
737 sk_load_func
= sk_load_word
;
739 case BPF_LD
| BPF_H
| BPF_IND
:
740 /* A <- P[X + k:2] */
741 sk_load_func
= sk_load_half
;
743 case BPF_LD
| BPF_B
| BPF_IND
:
744 /* A <- P[X + k:1] */
745 sk_load_func
= sk_load_byte
;
747 ctx
->flags
|= SEEN_OFF
| SEEN_X
;
748 emit_addiu(r_off
, r_X
, k
, ctx
);
750 case BPF_LDX
| BPF_IMM
:
752 ctx
->flags
|= SEEN_X
;
753 emit_load_imm(r_X
, k
, ctx
);
755 case BPF_LDX
| BPF_MEM
:
757 ctx
->flags
|= SEEN_X
| SEEN_MEM
;
758 emit_load(r_X
, r_M
, SCRATCH_OFF(k
), ctx
);
760 case BPF_LDX
| BPF_W
| BPF_LEN
:
762 ctx
->flags
|= SEEN_X
| SEEN_SKB
;
763 off
= offsetof(struct sk_buff
, len
);
764 emit_load(r_X
, r_skb
, off
, ctx
);
766 case BPF_LDX
| BPF_B
| BPF_MSH
:
767 /* X <- 4 * (P[k:1] & 0xf) */
768 ctx
->flags
|= SEEN_X
| SEEN_CALL
| SEEN_SKB
;
769 /* Load offset to a1 */
770 emit_load_func(r_s0
, (ptr
)sk_load_byte
, ctx
);
772 * This may emit two instructions so it may not fit
773 * in the delay slot. So use a0 in the delay slot.
775 emit_load_imm(MIPS_R_A1
, k
, ctx
);
776 emit_jalr(MIPS_R_RA
, r_s0
, ctx
);
777 emit_reg_move(MIPS_R_A0
, r_skb
, ctx
); /* delay slot */
778 /* Check the error value */
779 emit_bcond(MIPS_COND_NE
, r_ret
, 0,
780 b_imm(prog
->len
, ctx
), ctx
);
781 emit_reg_move(r_ret
, r_zero
, ctx
);
783 /* X <- P[1:K] & 0xf */
784 emit_andi(r_X
, r_A
, 0xf, ctx
);
786 emit_b(b_imm(i
+ 1, ctx
), ctx
);
787 emit_sll(r_X
, r_X
, 2, ctx
); /* delay slot */
791 ctx
->flags
|= SEEN_MEM
| SEEN_A
;
792 emit_store(r_A
, r_M
, SCRATCH_OFF(k
), ctx
);
796 ctx
->flags
|= SEEN_MEM
| SEEN_X
;
797 emit_store(r_X
, r_M
, SCRATCH_OFF(k
), ctx
);
799 case BPF_ALU
| BPF_ADD
| BPF_K
:
801 ctx
->flags
|= SEEN_A
;
802 emit_addiu(r_A
, r_A
, k
, ctx
);
804 case BPF_ALU
| BPF_ADD
| BPF_X
:
806 ctx
->flags
|= SEEN_A
| SEEN_X
;
807 emit_addu(r_A
, r_A
, r_X
, ctx
);
809 case BPF_ALU
| BPF_SUB
| BPF_K
:
811 ctx
->flags
|= SEEN_A
;
812 emit_addiu(r_A
, r_A
, -k
, ctx
);
814 case BPF_ALU
| BPF_SUB
| BPF_X
:
816 ctx
->flags
|= SEEN_A
| SEEN_X
;
817 emit_subu(r_A
, r_A
, r_X
, ctx
);
819 case BPF_ALU
| BPF_MUL
| BPF_K
:
821 /* Load K to scratch register before MUL */
822 ctx
->flags
|= SEEN_A
;
823 emit_load_imm(r_s0
, k
, ctx
);
824 emit_mul(r_A
, r_A
, r_s0
, ctx
);
826 case BPF_ALU
| BPF_MUL
| BPF_X
:
828 ctx
->flags
|= SEEN_A
| SEEN_X
;
829 emit_mul(r_A
, r_A
, r_X
, ctx
);
831 case BPF_ALU
| BPF_DIV
| BPF_K
:
835 if (optimize_div(&k
)) {
836 ctx
->flags
|= SEEN_A
;
837 emit_srl(r_A
, r_A
, k
, ctx
);
840 ctx
->flags
|= SEEN_A
;
841 emit_load_imm(r_s0
, k
, ctx
);
842 emit_div(r_A
, r_s0
, ctx
);
844 case BPF_ALU
| BPF_MOD
| BPF_K
:
847 ctx
->flags
|= SEEN_A
;
848 emit_jit_reg_move(r_A
, r_zero
, ctx
);
850 ctx
->flags
|= SEEN_A
;
851 emit_load_imm(r_s0
, k
, ctx
);
852 emit_mod(r_A
, r_s0
, ctx
);
855 case BPF_ALU
| BPF_DIV
| BPF_X
:
857 ctx
->flags
|= SEEN_X
| SEEN_A
;
858 /* Check if r_X is zero */
859 emit_bcond(MIPS_COND_EQ
, r_X
, r_zero
,
860 b_imm(prog
->len
, ctx
), ctx
);
861 emit_load_imm(r_ret
, 0, ctx
); /* delay slot */
862 emit_div(r_A
, r_X
, ctx
);
864 case BPF_ALU
| BPF_MOD
| BPF_X
:
866 ctx
->flags
|= SEEN_X
| SEEN_A
;
867 /* Check if r_X is zero */
868 emit_bcond(MIPS_COND_EQ
, r_X
, r_zero
,
869 b_imm(prog
->len
, ctx
), ctx
);
870 emit_load_imm(r_ret
, 0, ctx
); /* delay slot */
871 emit_mod(r_A
, r_X
, ctx
);
873 case BPF_ALU
| BPF_OR
| BPF_K
:
875 ctx
->flags
|= SEEN_A
;
876 emit_ori(r_A
, r_A
, k
, ctx
);
878 case BPF_ALU
| BPF_OR
| BPF_X
:
880 ctx
->flags
|= SEEN_A
;
881 emit_ori(r_A
, r_A
, r_X
, ctx
);
883 case BPF_ALU
| BPF_XOR
| BPF_K
:
885 ctx
->flags
|= SEEN_A
;
886 emit_xori(r_A
, r_A
, k
, ctx
);
888 case BPF_ANC
| SKF_AD_ALU_XOR_X
:
889 case BPF_ALU
| BPF_XOR
| BPF_X
:
891 ctx
->flags
|= SEEN_A
;
892 emit_xor(r_A
, r_A
, r_X
, ctx
);
894 case BPF_ALU
| BPF_AND
| BPF_K
:
896 ctx
->flags
|= SEEN_A
;
897 emit_andi(r_A
, r_A
, k
, ctx
);
899 case BPF_ALU
| BPF_AND
| BPF_X
:
901 ctx
->flags
|= SEEN_A
| SEEN_X
;
902 emit_and(r_A
, r_A
, r_X
, ctx
);
904 case BPF_ALU
| BPF_LSH
| BPF_K
:
906 ctx
->flags
|= SEEN_A
;
907 emit_sll(r_A
, r_A
, k
, ctx
);
909 case BPF_ALU
| BPF_LSH
| BPF_X
:
911 ctx
->flags
|= SEEN_A
| SEEN_X
;
912 emit_sllv(r_A
, r_A
, r_X
, ctx
);
914 case BPF_ALU
| BPF_RSH
| BPF_K
:
916 ctx
->flags
|= SEEN_A
;
917 emit_srl(r_A
, r_A
, k
, ctx
);
919 case BPF_ALU
| BPF_RSH
| BPF_X
:
920 ctx
->flags
|= SEEN_A
| SEEN_X
;
921 emit_srlv(r_A
, r_A
, r_X
, ctx
);
923 case BPF_ALU
| BPF_NEG
:
925 ctx
->flags
|= SEEN_A
;
928 case BPF_JMP
| BPF_JA
:
930 emit_b(b_imm(i
+ k
+ 1, ctx
), ctx
);
933 case BPF_JMP
| BPF_JEQ
| BPF_K
:
934 /* pc += ( A == K ) ? pc->jt : pc->jf */
935 condt
= MIPS_COND_EQ
| MIPS_COND_K
;
937 case BPF_JMP
| BPF_JEQ
| BPF_X
:
938 ctx
->flags
|= SEEN_X
;
939 /* pc += ( A == X ) ? pc->jt : pc->jf */
940 condt
= MIPS_COND_EQ
| MIPS_COND_X
;
942 case BPF_JMP
| BPF_JGE
| BPF_K
:
943 /* pc += ( A >= K ) ? pc->jt : pc->jf */
944 condt
= MIPS_COND_GE
| MIPS_COND_K
;
946 case BPF_JMP
| BPF_JGE
| BPF_X
:
947 ctx
->flags
|= SEEN_X
;
948 /* pc += ( A >= X ) ? pc->jt : pc->jf */
949 condt
= MIPS_COND_GE
| MIPS_COND_X
;
951 case BPF_JMP
| BPF_JGT
| BPF_K
:
952 /* pc += ( A > K ) ? pc->jt : pc->jf */
953 condt
= MIPS_COND_GT
| MIPS_COND_K
;
955 case BPF_JMP
| BPF_JGT
| BPF_X
:
956 ctx
->flags
|= SEEN_X
;
957 /* pc += ( A > X ) ? pc->jt : pc->jf */
958 condt
= MIPS_COND_GT
| MIPS_COND_X
;
960 /* Greater or Equal */
961 if ((condt
& MIPS_COND_GE
) ||
962 (condt
& MIPS_COND_GT
)) {
963 if (condt
& MIPS_COND_K
) { /* K */
964 ctx
->flags
|= SEEN_A
;
965 emit_sltiu(r_s0
, r_A
, k
, ctx
);
967 ctx
->flags
|= SEEN_A
|
969 emit_sltu(r_s0
, r_A
, r_X
, ctx
);
971 /* A < (K|X) ? r_scrach = 1 */
972 b_off
= b_imm(i
+ inst
->jf
+ 1, ctx
);
973 emit_bcond(MIPS_COND_NE
, r_s0
, r_zero
, b_off
,
976 /* A > (K|X) ? scratch = 0 */
977 if (condt
& MIPS_COND_GT
) {
978 /* Checking for equality */
979 ctx
->flags
|= SEEN_A
| SEEN_X
;
980 if (condt
& MIPS_COND_K
)
981 emit_load_imm(r_s0
, k
, ctx
);
983 emit_jit_reg_move(r_s0
, r_X
,
985 b_off
= b_imm(i
+ inst
->jf
+ 1, ctx
);
986 emit_bcond(MIPS_COND_EQ
, r_A
, r_s0
,
989 /* Finally, A > K|X */
990 b_off
= b_imm(i
+ inst
->jt
+ 1, ctx
);
994 /* A >= (K|X) so jump */
995 b_off
= b_imm(i
+ inst
->jt
+ 1, ctx
);
1001 if (condt
& MIPS_COND_K
) { /* K */
1002 ctx
->flags
|= SEEN_A
;
1003 emit_load_imm(r_s0
, k
, ctx
);
1005 b_off
= b_imm(i
+ inst
->jt
+ 1, ctx
);
1006 emit_bcond(MIPS_COND_EQ
, r_A
, r_s0
,
1010 b_off
= b_imm(i
+ inst
->jf
+ 1,
1012 emit_bcond(MIPS_COND_NE
, r_A
, r_s0
,
1017 ctx
->flags
|= SEEN_A
| SEEN_X
;
1018 b_off
= b_imm(i
+ inst
->jt
+ 1,
1020 emit_bcond(MIPS_COND_EQ
, r_A
, r_X
,
1024 b_off
= b_imm(i
+ inst
->jf
+ 1, ctx
);
1025 emit_bcond(MIPS_COND_NE
, r_A
, r_X
,
1031 case BPF_JMP
| BPF_JSET
| BPF_K
:
1032 ctx
->flags
|= SEEN_A
;
1033 /* pc += (A & K) ? pc -> jt : pc -> jf */
1034 emit_load_imm(r_s1
, k
, ctx
);
1035 emit_and(r_s0
, r_A
, r_s1
, ctx
);
1037 b_off
= b_imm(i
+ inst
->jt
+ 1, ctx
);
1038 emit_bcond(MIPS_COND_NE
, r_s0
, r_zero
, b_off
, ctx
);
1041 b_off
= b_imm(i
+ inst
->jf
+ 1, ctx
);
1045 case BPF_JMP
| BPF_JSET
| BPF_X
:
1046 ctx
->flags
|= SEEN_X
| SEEN_A
;
1047 /* pc += (A & X) ? pc -> jt : pc -> jf */
1048 emit_and(r_s0
, r_A
, r_X
, ctx
);
1050 b_off
= b_imm(i
+ inst
->jt
+ 1, ctx
);
1051 emit_bcond(MIPS_COND_NE
, r_s0
, r_zero
, b_off
, ctx
);
1054 b_off
= b_imm(i
+ inst
->jf
+ 1, ctx
);
1058 case BPF_RET
| BPF_A
:
1059 ctx
->flags
|= SEEN_A
;
1060 if (i
!= prog
->len
- 1)
1062 * If this is not the last instruction
1063 * then jump to the epilogue
1065 emit_b(b_imm(prog
->len
, ctx
), ctx
);
1066 emit_reg_move(r_ret
, r_A
, ctx
); /* delay slot */
1068 case BPF_RET
| BPF_K
:
1070 * It can emit two instructions so it does not fit on
1073 emit_load_imm(r_ret
, k
, ctx
);
1074 if (i
!= prog
->len
- 1) {
1076 * If this is not the last instruction
1077 * then jump to the epilogue
1079 emit_b(b_imm(prog
->len
, ctx
), ctx
);
1083 case BPF_MISC
| BPF_TAX
:
1085 ctx
->flags
|= SEEN_X
| SEEN_A
;
1086 emit_jit_reg_move(r_X
, r_A
, ctx
);
1088 case BPF_MISC
| BPF_TXA
:
1090 ctx
->flags
|= SEEN_A
| SEEN_X
;
1091 emit_jit_reg_move(r_A
, r_X
, ctx
);
1094 case BPF_ANC
| SKF_AD_PROTOCOL
:
1095 /* A = ntohs(skb->protocol */
1096 ctx
->flags
|= SEEN_SKB
| SEEN_OFF
| SEEN_A
;
1097 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
,
1099 off
= offsetof(struct sk_buff
, protocol
);
1100 emit_half_load(r_A
, r_skb
, off
, ctx
);
1101 #ifdef CONFIG_CPU_LITTLE_ENDIAN
1102 /* This needs little endian fixup */
1104 /* R2 and later have the wsbh instruction */
1105 emit_wsbh(r_A
, r_A
, ctx
);
1107 /* Get first byte */
1108 emit_andi(r_tmp_imm
, r_A
, 0xff, ctx
);
1110 emit_sll(r_tmp
, r_tmp_imm
, 8, ctx
);
1111 /* Get second byte */
1112 emit_srl(r_tmp_imm
, r_A
, 8, ctx
);
1113 emit_andi(r_tmp_imm
, r_tmp_imm
, 0xff, ctx
);
1114 /* Put everyting together in r_A */
1115 emit_or(r_A
, r_tmp
, r_tmp_imm
, ctx
);
1119 case BPF_ANC
| SKF_AD_CPU
:
1120 ctx
->flags
|= SEEN_A
| SEEN_OFF
;
1121 /* A = current_thread_info()->cpu */
1122 BUILD_BUG_ON(FIELD_SIZEOF(struct thread_info
,
1124 off
= offsetof(struct thread_info
, cpu
);
1125 /* $28/gp points to the thread_info struct */
1126 emit_load(r_A
, 28, off
, ctx
);
1128 case BPF_ANC
| SKF_AD_IFINDEX
:
1129 /* A = skb->dev->ifindex */
1130 ctx
->flags
|= SEEN_SKB
| SEEN_A
;
1131 off
= offsetof(struct sk_buff
, dev
);
1132 /* Load *dev pointer */
1133 emit_load_ptr(r_s0
, r_skb
, off
, ctx
);
1134 /* error (0) in the delay slot */
1135 emit_bcond(MIPS_COND_EQ
, r_s0
, r_zero
,
1136 b_imm(prog
->len
, ctx
), ctx
);
1137 emit_reg_move(r_ret
, r_zero
, ctx
);
1138 BUILD_BUG_ON(FIELD_SIZEOF(struct net_device
,
1140 off
= offsetof(struct net_device
, ifindex
);
1141 emit_load(r_A
, r_s0
, off
, ctx
);
1143 case BPF_ANC
| SKF_AD_MARK
:
1144 ctx
->flags
|= SEEN_SKB
| SEEN_A
;
1145 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, mark
) != 4);
1146 off
= offsetof(struct sk_buff
, mark
);
1147 emit_load(r_A
, r_skb
, off
, ctx
);
1149 case BPF_ANC
| SKF_AD_RXHASH
:
1150 ctx
->flags
|= SEEN_SKB
| SEEN_A
;
1151 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
, hash
) != 4);
1152 off
= offsetof(struct sk_buff
, hash
);
1153 emit_load(r_A
, r_skb
, off
, ctx
);
1155 case BPF_ANC
| SKF_AD_VLAN_TAG
:
1156 case BPF_ANC
| SKF_AD_VLAN_TAG_PRESENT
:
1157 ctx
->flags
|= SEEN_SKB
| SEEN_A
;
1158 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
,
1160 off
= offsetof(struct sk_buff
, vlan_tci
);
1161 emit_half_load(r_s0
, r_skb
, off
, ctx
);
1162 if (code
== (BPF_ANC
| SKF_AD_VLAN_TAG
)) {
1163 emit_andi(r_A
, r_s0
, (u16
)~VLAN_TAG_PRESENT
, ctx
);
1165 emit_andi(r_A
, r_s0
, VLAN_TAG_PRESENT
, ctx
);
1166 /* return 1 if present */
1167 emit_sltu(r_A
, r_zero
, r_A
, ctx
);
1170 case BPF_ANC
| SKF_AD_PKTTYPE
:
1171 ctx
->flags
|= SEEN_SKB
;
1173 emit_load_byte(r_tmp
, r_skb
, PKT_TYPE_OFFSET(), ctx
);
1174 /* Keep only the last 3 bits */
1175 emit_andi(r_A
, r_tmp
, PKT_TYPE_MAX
, ctx
);
1176 #ifdef __BIG_ENDIAN_BITFIELD
1177 /* Get the actual packet type to the lower 3 bits */
1178 emit_srl(r_A
, r_A
, 5, ctx
);
1181 case BPF_ANC
| SKF_AD_QUEUE
:
1182 ctx
->flags
|= SEEN_SKB
| SEEN_A
;
1183 BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff
,
1184 queue_mapping
) != 2);
1185 BUILD_BUG_ON(offsetof(struct sk_buff
,
1186 queue_mapping
) > 0xff);
1187 off
= offsetof(struct sk_buff
, queue_mapping
);
1188 emit_half_load(r_A
, r_skb
, off
, ctx
);
1191 pr_debug("%s: Unhandled opcode: 0x%02x\n", __FILE__
,
1197 /* compute offsets only during the first pass */
1198 if (ctx
->target
== NULL
)
1199 ctx
->offsets
[i
] = ctx
->idx
* 4;
1204 int bpf_jit_enable __read_mostly
;
1206 void bpf_jit_compile(struct bpf_prog
*fp
)
1209 unsigned int alloc_size
, tmp_idx
;
1211 if (!bpf_jit_enable
)
1214 memset(&ctx
, 0, sizeof(ctx
));
1216 ctx
.offsets
= kcalloc(fp
->len
, sizeof(*ctx
.offsets
), GFP_KERNEL
);
1217 if (ctx
.offsets
== NULL
)
1222 if (build_body(&ctx
))
1226 build_prologue(&ctx
);
1227 ctx
.prologue_bytes
= (ctx
.idx
- tmp_idx
) * 4;
1228 /* just to complete the ctx.idx count */
1229 build_epilogue(&ctx
);
1231 alloc_size
= 4 * ctx
.idx
;
1232 ctx
.target
= module_alloc(alloc_size
);
1233 if (ctx
.target
== NULL
)
1237 memset(ctx
.target
, 0, alloc_size
);
1241 /* Generate the actual JIT code */
1242 build_prologue(&ctx
);
1244 build_epilogue(&ctx
);
1246 /* Update the icache */
1247 flush_icache_range((ptr
)ctx
.target
, (ptr
)(ctx
.target
+ ctx
.idx
));
1249 if (bpf_jit_enable
> 1)
1251 bpf_jit_dump(fp
->len
, alloc_size
, 2, ctx
.target
);
1253 fp
->bpf_func
= (void *)ctx
.target
;
1260 void bpf_jit_free(struct bpf_prog
*fp
)
1263 module_memfree(fp
->bpf_func
);
1265 bpf_prog_unlock_free(fp
);