Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Just-In-Time compiler for BPF filters on 32bit ARM |
| 3 | * |
| 4 | * Copyright (c) 2011 Mircea Gherzan <mgherzan@gmail.com> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify it |
| 7 | * under the terms of the GNU General Public License as published by the |
| 8 | * Free Software Foundation; version 2 of the License. |
| 9 | */ |
| 10 | |
| 11 | #include <linux/bitops.h> |
| 12 | #include <linux/compiler.h> |
| 13 | #include <linux/errno.h> |
| 14 | #include <linux/filter.h> |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 15 | #include <linux/netdevice.h> |
| 16 | #include <linux/string.h> |
| 17 | #include <linux/slab.h> |
Daniel Borkmann | bf0098f | 2012-11-07 15:31:02 +0000 | [diff] [blame] | 18 | #include <linux/if_vlan.h> |
Daniel Borkmann | e8b56d5 | 2014-09-19 14:56:57 +0200 | [diff] [blame] | 19 | |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 20 | #include <asm/cacheflush.h> |
| 21 | #include <asm/hwcap.h> |
Ben Dooks | 3460743 | 2013-07-24 15:44:56 +0100 | [diff] [blame] | 22 | #include <asm/opcodes.h> |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 23 | |
| 24 | #include "bpf_jit_32.h" |
| 25 | |
| 26 | /* |
| 27 | * ABI: |
| 28 | * |
| 29 | * r0 scratch register |
| 30 | * r4 BPF register A |
| 31 | * r5 BPF register X |
| 32 | * r6 pointer to the skb |
| 33 | * r7 skb->data |
| 34 | * r8 skb_headlen(skb) |
| 35 | */ |
| 36 | |
| 37 | #define r_scratch ARM_R0 |
| 38 | /* r1-r3 are (also) used for the unaligned loads on the non-ARMv7 slowpath */ |
| 39 | #define r_off ARM_R1 |
| 40 | #define r_A ARM_R4 |
| 41 | #define r_X ARM_R5 |
| 42 | #define r_skb ARM_R6 |
| 43 | #define r_skb_data ARM_R7 |
| 44 | #define r_skb_hl ARM_R8 |
| 45 | |
| 46 | #define SCRATCH_SP_OFFSET 0 |
Schichan Nicolas | fe15f3f | 2012-12-10 14:49:40 +0100 | [diff] [blame] | 47 | #define SCRATCH_OFF(k) (SCRATCH_SP_OFFSET + 4 * (k)) |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 48 | |
| 49 | #define SEEN_MEM ((1 << BPF_MEMWORDS) - 1) |
| 50 | #define SEEN_MEM_WORD(k) (1 << (k)) |
| 51 | #define SEEN_X (1 << BPF_MEMWORDS) |
| 52 | #define SEEN_CALL (1 << (BPF_MEMWORDS + 1)) |
| 53 | #define SEEN_SKB (1 << (BPF_MEMWORDS + 2)) |
| 54 | #define SEEN_DATA (1 << (BPF_MEMWORDS + 3)) |
| 55 | |
| 56 | #define FLAG_NEED_X_RESET (1 << 0) |
Nicolas Schichan | 0b59d88 | 2015-05-07 17:14:21 +0200 | [diff] [blame] | 57 | #define FLAG_IMM_OVERFLOW (1 << 1) |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 58 | |
| 59 | struct jit_ctx { |
Alexei Starovoitov | 7ae457c | 2014-07-30 20:34:16 -0700 | [diff] [blame] | 60 | const struct bpf_prog *skf; |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 61 | unsigned idx; |
| 62 | unsigned prologue_bytes; |
| 63 | int ret0_fp_idx; |
| 64 | u32 seen; |
| 65 | u32 flags; |
| 66 | u32 *offsets; |
| 67 | u32 *target; |
| 68 | #if __LINUX_ARM_ARCH__ < 7 |
| 69 | u16 epilogue_bytes; |
| 70 | u16 imm_count; |
| 71 | u32 *imms; |
| 72 | #endif |
| 73 | }; |
| 74 | |
Nicolas Schichan | 6d715e3 | 2015-07-21 14:14:13 +0200 | [diff] [blame] | 75 | static inline int call_neg_helper(struct sk_buff *skb, int offset, void *ret, |
| 76 | unsigned int size) |
| 77 | { |
| 78 | void *ptr = bpf_internal_load_pointer_neg_helper(skb, offset, size); |
| 79 | |
| 80 | if (!ptr) |
| 81 | return -EFAULT; |
| 82 | memcpy(ret, ptr, size); |
| 83 | return 0; |
| 84 | } |
| 85 | |
| 86 | static u64 jit_get_skb_b(struct sk_buff *skb, int offset) |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 87 | { |
| 88 | u8 ret; |
| 89 | int err; |
| 90 | |
Nicolas Schichan | 6d715e3 | 2015-07-21 14:14:13 +0200 | [diff] [blame] | 91 | if (offset < 0) |
| 92 | err = call_neg_helper(skb, offset, &ret, 1); |
| 93 | else |
| 94 | err = skb_copy_bits(skb, offset, &ret, 1); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 95 | |
| 96 | return (u64)err << 32 | ret; |
| 97 | } |
| 98 | |
Nicolas Schichan | 6d715e3 | 2015-07-21 14:14:13 +0200 | [diff] [blame] | 99 | static u64 jit_get_skb_h(struct sk_buff *skb, int offset) |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 100 | { |
| 101 | u16 ret; |
| 102 | int err; |
| 103 | |
Nicolas Schichan | 6d715e3 | 2015-07-21 14:14:13 +0200 | [diff] [blame] | 104 | if (offset < 0) |
| 105 | err = call_neg_helper(skb, offset, &ret, 2); |
| 106 | else |
| 107 | err = skb_copy_bits(skb, offset, &ret, 2); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 108 | |
| 109 | return (u64)err << 32 | ntohs(ret); |
| 110 | } |
| 111 | |
Nicolas Schichan | 6d715e3 | 2015-07-21 14:14:13 +0200 | [diff] [blame] | 112 | static u64 jit_get_skb_w(struct sk_buff *skb, int offset) |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 113 | { |
| 114 | u32 ret; |
| 115 | int err; |
| 116 | |
Nicolas Schichan | 6d715e3 | 2015-07-21 14:14:13 +0200 | [diff] [blame] | 117 | if (offset < 0) |
| 118 | err = call_neg_helper(skb, offset, &ret, 4); |
| 119 | else |
| 120 | err = skb_copy_bits(skb, offset, &ret, 4); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 121 | |
| 122 | return (u64)err << 32 | ntohl(ret); |
| 123 | } |
| 124 | |
| 125 | /* |
Nicolas Schichan | 4560cdf | 2015-10-02 17:06:47 +0200 | [diff] [blame] | 126 | * Wrappers which handle both OABI and EABI and assures Thumb2 interworking |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 127 | * (where the assembly routines like __aeabi_uidiv could cause problems). |
| 128 | */ |
| 129 | static u32 jit_udiv(u32 dividend, u32 divisor) |
| 130 | { |
| 131 | return dividend / divisor; |
| 132 | } |
| 133 | |
Nicolas Schichan | 4560cdf | 2015-10-02 17:06:47 +0200 | [diff] [blame] | 134 | static u32 jit_mod(u32 dividend, u32 divisor) |
| 135 | { |
| 136 | return dividend % divisor; |
| 137 | } |
| 138 | |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 139 | static inline void _emit(int cond, u32 inst, struct jit_ctx *ctx) |
| 140 | { |
Ben Dooks | 3460743 | 2013-07-24 15:44:56 +0100 | [diff] [blame] | 141 | inst |= (cond << 28); |
| 142 | inst = __opcode_to_mem_arm(inst); |
| 143 | |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 144 | if (ctx->target != NULL) |
Ben Dooks | 3460743 | 2013-07-24 15:44:56 +0100 | [diff] [blame] | 145 | ctx->target[ctx->idx] = inst; |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 146 | |
| 147 | ctx->idx++; |
| 148 | } |
| 149 | |
| 150 | /* |
| 151 | * Emit an instruction that will be executed unconditionally. |
| 152 | */ |
| 153 | static inline void emit(u32 inst, struct jit_ctx *ctx) |
| 154 | { |
| 155 | _emit(ARM_COND_AL, inst, ctx); |
| 156 | } |
| 157 | |
| 158 | static u16 saved_regs(struct jit_ctx *ctx) |
| 159 | { |
| 160 | u16 ret = 0; |
| 161 | |
| 162 | if ((ctx->skf->len > 1) || |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 163 | (ctx->skf->insns[0].code == (BPF_RET | BPF_A))) |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 164 | ret |= 1 << r_A; |
| 165 | |
| 166 | #ifdef CONFIG_FRAME_POINTER |
| 167 | ret |= (1 << ARM_FP) | (1 << ARM_IP) | (1 << ARM_LR) | (1 << ARM_PC); |
| 168 | #else |
| 169 | if (ctx->seen & SEEN_CALL) |
| 170 | ret |= 1 << ARM_LR; |
| 171 | #endif |
| 172 | if (ctx->seen & (SEEN_DATA | SEEN_SKB)) |
| 173 | ret |= 1 << r_skb; |
| 174 | if (ctx->seen & SEEN_DATA) |
| 175 | ret |= (1 << r_skb_data) | (1 << r_skb_hl); |
| 176 | if (ctx->seen & SEEN_X) |
| 177 | ret |= 1 << r_X; |
| 178 | |
| 179 | return ret; |
| 180 | } |
| 181 | |
| 182 | static inline int mem_words_used(struct jit_ctx *ctx) |
| 183 | { |
| 184 | /* yes, we do waste some stack space IF there are "holes" in the set" */ |
| 185 | return fls(ctx->seen & SEEN_MEM); |
| 186 | } |
| 187 | |
Daniel Borkmann | 55309dd | 2014-09-08 08:04:48 +0200 | [diff] [blame] | 188 | static void jit_fill_hole(void *area, unsigned int size) |
| 189 | { |
Daniel Borkmann | e8b56d5 | 2014-09-19 14:56:57 +0200 | [diff] [blame] | 190 | u32 *ptr; |
Daniel Borkmann | 55309dd | 2014-09-08 08:04:48 +0200 | [diff] [blame] | 191 | /* We are guaranteed to have aligned memory. */ |
| 192 | for (ptr = area; size >= sizeof(u32); size -= sizeof(u32)) |
Daniel Borkmann | e8b56d5 | 2014-09-19 14:56:57 +0200 | [diff] [blame] | 193 | *ptr++ = __opcode_to_mem_arm(ARM_INST_UDF); |
Daniel Borkmann | 55309dd | 2014-09-08 08:04:48 +0200 | [diff] [blame] | 194 | } |
| 195 | |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 196 | static void build_prologue(struct jit_ctx *ctx) |
| 197 | { |
| 198 | u16 reg_set = saved_regs(ctx); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 199 | u16 off; |
| 200 | |
| 201 | #ifdef CONFIG_FRAME_POINTER |
| 202 | emit(ARM_MOV_R(ARM_IP, ARM_SP), ctx); |
| 203 | emit(ARM_PUSH(reg_set), ctx); |
| 204 | emit(ARM_SUB_I(ARM_FP, ARM_IP, 4), ctx); |
| 205 | #else |
| 206 | if (reg_set) |
| 207 | emit(ARM_PUSH(reg_set), ctx); |
| 208 | #endif |
| 209 | |
| 210 | if (ctx->seen & (SEEN_DATA | SEEN_SKB)) |
| 211 | emit(ARM_MOV_R(r_skb, ARM_R0), ctx); |
| 212 | |
| 213 | if (ctx->seen & SEEN_DATA) { |
| 214 | off = offsetof(struct sk_buff, data); |
| 215 | emit(ARM_LDR_I(r_skb_data, r_skb, off), ctx); |
| 216 | /* headlen = len - data_len */ |
| 217 | off = offsetof(struct sk_buff, len); |
| 218 | emit(ARM_LDR_I(r_skb_hl, r_skb, off), ctx); |
| 219 | off = offsetof(struct sk_buff, data_len); |
| 220 | emit(ARM_LDR_I(r_scratch, r_skb, off), ctx); |
| 221 | emit(ARM_SUB_R(r_skb_hl, r_skb_hl, r_scratch), ctx); |
| 222 | } |
| 223 | |
| 224 | if (ctx->flags & FLAG_NEED_X_RESET) |
| 225 | emit(ARM_MOV_I(r_X, 0), ctx); |
| 226 | |
| 227 | /* do not leak kernel data to userspace */ |
Rabin Vincent | 55795ef | 2016-01-05 16:23:07 +0100 | [diff] [blame] | 228 | if (bpf_needs_clear_a(&ctx->skf->insns[0])) |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 229 | emit(ARM_MOV_I(r_A, 0), ctx); |
| 230 | |
| 231 | /* stack space for the BPF_MEM words */ |
| 232 | if (ctx->seen & SEEN_MEM) |
| 233 | emit(ARM_SUB_I(ARM_SP, ARM_SP, mem_words_used(ctx) * 4), ctx); |
| 234 | } |
| 235 | |
| 236 | static void build_epilogue(struct jit_ctx *ctx) |
| 237 | { |
| 238 | u16 reg_set = saved_regs(ctx); |
| 239 | |
| 240 | if (ctx->seen & SEEN_MEM) |
| 241 | emit(ARM_ADD_I(ARM_SP, ARM_SP, mem_words_used(ctx) * 4), ctx); |
| 242 | |
| 243 | reg_set &= ~(1 << ARM_LR); |
| 244 | |
| 245 | #ifdef CONFIG_FRAME_POINTER |
| 246 | /* the first instruction of the prologue was: mov ip, sp */ |
| 247 | reg_set &= ~(1 << ARM_IP); |
| 248 | reg_set |= (1 << ARM_SP); |
| 249 | emit(ARM_LDM(ARM_SP, reg_set), ctx); |
| 250 | #else |
| 251 | if (reg_set) { |
| 252 | if (ctx->seen & SEEN_CALL) |
| 253 | reg_set |= 1 << ARM_PC; |
| 254 | emit(ARM_POP(reg_set), ctx); |
| 255 | } |
| 256 | |
| 257 | if (!(ctx->seen & SEEN_CALL)) |
| 258 | emit(ARM_BX(ARM_LR), ctx); |
| 259 | #endif |
| 260 | } |
| 261 | |
| 262 | static int16_t imm8m(u32 x) |
| 263 | { |
| 264 | u32 rot; |
| 265 | |
| 266 | for (rot = 0; rot < 16; rot++) |
| 267 | if ((x & ~ror32(0xff, 2 * rot)) == 0) |
| 268 | return rol32(x, 2 * rot) | (rot << 8); |
| 269 | |
| 270 | return -1; |
| 271 | } |
| 272 | |
| 273 | #if __LINUX_ARM_ARCH__ < 7 |
| 274 | |
| 275 | static u16 imm_offset(u32 k, struct jit_ctx *ctx) |
| 276 | { |
| 277 | unsigned i = 0, offset; |
| 278 | u16 imm; |
| 279 | |
| 280 | /* on the "fake" run we just count them (duplicates included) */ |
| 281 | if (ctx->target == NULL) { |
| 282 | ctx->imm_count++; |
| 283 | return 0; |
| 284 | } |
| 285 | |
| 286 | while ((i < ctx->imm_count) && ctx->imms[i]) { |
| 287 | if (ctx->imms[i] == k) |
| 288 | break; |
| 289 | i++; |
| 290 | } |
| 291 | |
| 292 | if (ctx->imms[i] == 0) |
| 293 | ctx->imms[i] = k; |
| 294 | |
| 295 | /* constants go just after the epilogue */ |
| 296 | offset = ctx->offsets[ctx->skf->len]; |
| 297 | offset += ctx->prologue_bytes; |
| 298 | offset += ctx->epilogue_bytes; |
| 299 | offset += i * 4; |
| 300 | |
| 301 | ctx->target[offset / 4] = k; |
| 302 | |
| 303 | /* PC in ARM mode == address of the instruction + 8 */ |
| 304 | imm = offset - (8 + ctx->idx * 4); |
| 305 | |
Nicolas Schichan | 0b59d88 | 2015-05-07 17:14:21 +0200 | [diff] [blame] | 306 | if (imm & ~0xfff) { |
| 307 | /* |
| 308 | * literal pool is too far, signal it into flags. we |
| 309 | * can only detect it on the second pass unfortunately. |
| 310 | */ |
| 311 | ctx->flags |= FLAG_IMM_OVERFLOW; |
| 312 | return 0; |
| 313 | } |
| 314 | |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 315 | return imm; |
| 316 | } |
| 317 | |
| 318 | #endif /* __LINUX_ARM_ARCH__ */ |
| 319 | |
| 320 | /* |
| 321 | * Move an immediate that's not an imm8m to a core register. |
| 322 | */ |
| 323 | static inline void emit_mov_i_no8m(int rd, u32 val, struct jit_ctx *ctx) |
| 324 | { |
| 325 | #if __LINUX_ARM_ARCH__ < 7 |
| 326 | emit(ARM_LDR_I(rd, ARM_PC, imm_offset(val, ctx)), ctx); |
| 327 | #else |
| 328 | emit(ARM_MOVW(rd, val & 0xffff), ctx); |
| 329 | if (val > 0xffff) |
| 330 | emit(ARM_MOVT(rd, val >> 16), ctx); |
| 331 | #endif |
| 332 | } |
| 333 | |
| 334 | static inline void emit_mov_i(int rd, u32 val, struct jit_ctx *ctx) |
| 335 | { |
| 336 | int imm12 = imm8m(val); |
| 337 | |
| 338 | if (imm12 >= 0) |
| 339 | emit(ARM_MOV_I(rd, imm12), ctx); |
| 340 | else |
| 341 | emit_mov_i_no8m(rd, val, ctx); |
| 342 | } |
| 343 | |
| 344 | #if __LINUX_ARM_ARCH__ < 6 |
| 345 | |
| 346 | static void emit_load_be32(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx) |
| 347 | { |
| 348 | _emit(cond, ARM_LDRB_I(ARM_R3, r_addr, 1), ctx); |
| 349 | _emit(cond, ARM_LDRB_I(ARM_R1, r_addr, 0), ctx); |
| 350 | _emit(cond, ARM_LDRB_I(ARM_R2, r_addr, 3), ctx); |
| 351 | _emit(cond, ARM_LSL_I(ARM_R3, ARM_R3, 16), ctx); |
| 352 | _emit(cond, ARM_LDRB_I(ARM_R0, r_addr, 2), ctx); |
| 353 | _emit(cond, ARM_ORR_S(ARM_R3, ARM_R3, ARM_R1, SRTYPE_LSL, 24), ctx); |
| 354 | _emit(cond, ARM_ORR_R(ARM_R3, ARM_R3, ARM_R2), ctx); |
| 355 | _emit(cond, ARM_ORR_S(r_res, ARM_R3, ARM_R0, SRTYPE_LSL, 8), ctx); |
| 356 | } |
| 357 | |
| 358 | static void emit_load_be16(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx) |
| 359 | { |
| 360 | _emit(cond, ARM_LDRB_I(ARM_R1, r_addr, 0), ctx); |
| 361 | _emit(cond, ARM_LDRB_I(ARM_R2, r_addr, 1), ctx); |
| 362 | _emit(cond, ARM_ORR_S(r_res, ARM_R2, ARM_R1, SRTYPE_LSL, 8), ctx); |
| 363 | } |
| 364 | |
| 365 | static inline void emit_swap16(u8 r_dst, u8 r_src, struct jit_ctx *ctx) |
| 366 | { |
Nicolas Schichan | 462738f | 2013-02-13 17:30:39 +0000 | [diff] [blame] | 367 | /* r_dst = (r_src << 8) | (r_src >> 8) */ |
| 368 | emit(ARM_LSL_I(ARM_R1, r_src, 8), ctx); |
| 369 | emit(ARM_ORR_S(r_dst, ARM_R1, r_src, SRTYPE_LSR, 8), ctx); |
| 370 | |
| 371 | /* |
| 372 | * we need to mask out the bits set in r_dst[23:16] due to |
| 373 | * the first shift instruction. |
| 374 | * |
| 375 | * note that 0x8ff is the encoded immediate 0x00ff0000. |
| 376 | */ |
| 377 | emit(ARM_BIC_I(r_dst, r_dst, 0x8ff), ctx); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 378 | } |
| 379 | |
| 380 | #else /* ARMv6+ */ |
| 381 | |
| 382 | static void emit_load_be32(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx) |
| 383 | { |
| 384 | _emit(cond, ARM_LDR_I(r_res, r_addr, 0), ctx); |
| 385 | #ifdef __LITTLE_ENDIAN |
| 386 | _emit(cond, ARM_REV(r_res, r_res), ctx); |
| 387 | #endif |
| 388 | } |
| 389 | |
| 390 | static void emit_load_be16(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx) |
| 391 | { |
| 392 | _emit(cond, ARM_LDRH_I(r_res, r_addr, 0), ctx); |
| 393 | #ifdef __LITTLE_ENDIAN |
| 394 | _emit(cond, ARM_REV16(r_res, r_res), ctx); |
| 395 | #endif |
| 396 | } |
| 397 | |
| 398 | static inline void emit_swap16(u8 r_dst __maybe_unused, |
| 399 | u8 r_src __maybe_unused, |
| 400 | struct jit_ctx *ctx __maybe_unused) |
| 401 | { |
| 402 | #ifdef __LITTLE_ENDIAN |
| 403 | emit(ARM_REV16(r_dst, r_src), ctx); |
| 404 | #endif |
| 405 | } |
| 406 | |
| 407 | #endif /* __LINUX_ARM_ARCH__ < 6 */ |
| 408 | |
| 409 | |
| 410 | /* Compute the immediate value for a PC-relative branch. */ |
| 411 | static inline u32 b_imm(unsigned tgt, struct jit_ctx *ctx) |
| 412 | { |
| 413 | u32 imm; |
| 414 | |
| 415 | if (ctx->target == NULL) |
| 416 | return 0; |
| 417 | /* |
| 418 | * BPF allows only forward jumps and the offset of the target is |
| 419 | * still the one computed during the first pass. |
| 420 | */ |
| 421 | imm = ctx->offsets[tgt] + ctx->prologue_bytes - (ctx->idx * 4 + 8); |
| 422 | |
| 423 | return imm >> 2; |
| 424 | } |
| 425 | |
| 426 | #define OP_IMM3(op, r1, r2, imm_val, ctx) \ |
| 427 | do { \ |
| 428 | imm12 = imm8m(imm_val); \ |
| 429 | if (imm12 < 0) { \ |
| 430 | emit_mov_i_no8m(r_scratch, imm_val, ctx); \ |
| 431 | emit(op ## _R((r1), (r2), r_scratch), ctx); \ |
| 432 | } else { \ |
| 433 | emit(op ## _I((r1), (r2), imm12), ctx); \ |
| 434 | } \ |
| 435 | } while (0) |
| 436 | |
| 437 | static inline void emit_err_ret(u8 cond, struct jit_ctx *ctx) |
| 438 | { |
| 439 | if (ctx->ret0_fp_idx >= 0) { |
| 440 | _emit(cond, ARM_B(b_imm(ctx->ret0_fp_idx, ctx)), ctx); |
| 441 | /* NOP to keep the size constant between passes */ |
| 442 | emit(ARM_MOV_R(ARM_R0, ARM_R0), ctx); |
| 443 | } else { |
| 444 | _emit(cond, ARM_MOV_I(ARM_R0, 0), ctx); |
| 445 | _emit(cond, ARM_B(b_imm(ctx->skf->len, ctx)), ctx); |
| 446 | } |
| 447 | } |
| 448 | |
| 449 | static inline void emit_blx_r(u8 tgt_reg, struct jit_ctx *ctx) |
| 450 | { |
| 451 | #if __LINUX_ARM_ARCH__ < 5 |
| 452 | emit(ARM_MOV_R(ARM_LR, ARM_PC), ctx); |
| 453 | |
| 454 | if (elf_hwcap & HWCAP_THUMB) |
| 455 | emit(ARM_BX(tgt_reg), ctx); |
| 456 | else |
| 457 | emit(ARM_MOV_R(ARM_PC, tgt_reg), ctx); |
| 458 | #else |
| 459 | emit(ARM_BLX_R(tgt_reg), ctx); |
| 460 | #endif |
| 461 | } |
| 462 | |
Nicolas Schichan | 4560cdf | 2015-10-02 17:06:47 +0200 | [diff] [blame] | 463 | static inline void emit_udivmod(u8 rd, u8 rm, u8 rn, struct jit_ctx *ctx, |
| 464 | int bpf_op) |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 465 | { |
| 466 | #if __LINUX_ARM_ARCH__ == 7 |
| 467 | if (elf_hwcap & HWCAP_IDIVA) { |
Nicolas Schichan | 4560cdf | 2015-10-02 17:06:47 +0200 | [diff] [blame] | 468 | if (bpf_op == BPF_DIV) |
| 469 | emit(ARM_UDIV(rd, rm, rn), ctx); |
| 470 | else { |
| 471 | emit(ARM_UDIV(ARM_R3, rm, rn), ctx); |
| 472 | emit(ARM_MLS(rd, rn, ARM_R3, rm), ctx); |
| 473 | } |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 474 | return; |
| 475 | } |
| 476 | #endif |
Nicolas Schichan | 19fc99d | 2015-05-06 18:31:56 +0200 | [diff] [blame] | 477 | |
| 478 | /* |
| 479 | * For BPF_ALU | BPF_DIV | BPF_K instructions, rm is ARM_R4 |
| 480 | * (r_A) and rn is ARM_R0 (r_scratch) so load rn first into |
| 481 | * ARM_R1 to avoid accidentally overwriting ARM_R0 with rm |
| 482 | * before using it as a source for ARM_R1. |
| 483 | * |
| 484 | * For BPF_ALU | BPF_DIV | BPF_X rm is ARM_R4 (r_A) and rn is |
| 485 | * ARM_R5 (r_X) so there is no particular register overlap |
| 486 | * issues. |
| 487 | */ |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 488 | if (rn != ARM_R1) |
| 489 | emit(ARM_MOV_R(ARM_R1, rn), ctx); |
Nicolas Schichan | 19fc99d | 2015-05-06 18:31:56 +0200 | [diff] [blame] | 490 | if (rm != ARM_R0) |
| 491 | emit(ARM_MOV_R(ARM_R0, rm), ctx); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 492 | |
| 493 | ctx->seen |= SEEN_CALL; |
Nicolas Schichan | 4560cdf | 2015-10-02 17:06:47 +0200 | [diff] [blame] | 494 | emit_mov_i(ARM_R3, bpf_op == BPF_DIV ? (u32)jit_udiv : (u32)jit_mod, |
| 495 | ctx); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 496 | emit_blx_r(ARM_R3, ctx); |
| 497 | |
| 498 | if (rd != ARM_R0) |
| 499 | emit(ARM_MOV_R(rd, ARM_R0), ctx); |
| 500 | } |
| 501 | |
| 502 | static inline void update_on_xread(struct jit_ctx *ctx) |
| 503 | { |
| 504 | if (!(ctx->seen & SEEN_X)) |
| 505 | ctx->flags |= FLAG_NEED_X_RESET; |
| 506 | |
| 507 | ctx->seen |= SEEN_X; |
| 508 | } |
| 509 | |
| 510 | static int build_body(struct jit_ctx *ctx) |
| 511 | { |
| 512 | void *load_func[] = {jit_get_skb_b, jit_get_skb_h, jit_get_skb_w}; |
Alexei Starovoitov | 7ae457c | 2014-07-30 20:34:16 -0700 | [diff] [blame] | 513 | const struct bpf_prog *prog = ctx->skf; |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 514 | const struct sock_filter *inst; |
| 515 | unsigned i, load_order, off, condt; |
| 516 | int imm12; |
| 517 | u32 k; |
| 518 | |
| 519 | for (i = 0; i < prog->len; i++) { |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 520 | u16 code; |
| 521 | |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 522 | inst = &(prog->insns[i]); |
| 523 | /* K as an immediate value operand */ |
| 524 | k = inst->k; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 525 | code = bpf_anc_helper(inst); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 526 | |
| 527 | /* compute offsets only in the fake pass */ |
| 528 | if (ctx->target == NULL) |
| 529 | ctx->offsets[i] = ctx->idx * 4; |
| 530 | |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 531 | switch (code) { |
| 532 | case BPF_LD | BPF_IMM: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 533 | emit_mov_i(r_A, k, ctx); |
| 534 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 535 | case BPF_LD | BPF_W | BPF_LEN: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 536 | ctx->seen |= SEEN_SKB; |
| 537 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4); |
| 538 | emit(ARM_LDR_I(r_A, r_skb, |
| 539 | offsetof(struct sk_buff, len)), ctx); |
| 540 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 541 | case BPF_LD | BPF_MEM: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 542 | /* A = scratch[k] */ |
| 543 | ctx->seen |= SEEN_MEM_WORD(k); |
| 544 | emit(ARM_LDR_I(r_A, ARM_SP, SCRATCH_OFF(k)), ctx); |
| 545 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 546 | case BPF_LD | BPF_W | BPF_ABS: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 547 | load_order = 2; |
| 548 | goto load; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 549 | case BPF_LD | BPF_H | BPF_ABS: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 550 | load_order = 1; |
| 551 | goto load; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 552 | case BPF_LD | BPF_B | BPF_ABS: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 553 | load_order = 0; |
| 554 | load: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 555 | emit_mov_i(r_off, k, ctx); |
| 556 | load_common: |
| 557 | ctx->seen |= SEEN_DATA | SEEN_CALL; |
| 558 | |
| 559 | if (load_order > 0) { |
| 560 | emit(ARM_SUB_I(r_scratch, r_skb_hl, |
| 561 | 1 << load_order), ctx); |
| 562 | emit(ARM_CMP_R(r_scratch, r_off), ctx); |
Nicolas Schichan | 7aed35c | 2015-07-21 14:14:12 +0200 | [diff] [blame] | 563 | condt = ARM_COND_GE; |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 564 | } else { |
| 565 | emit(ARM_CMP_R(r_skb_hl, r_off), ctx); |
| 566 | condt = ARM_COND_HI; |
| 567 | } |
| 568 | |
Nicolas Schichan | 6d715e3 | 2015-07-21 14:14:13 +0200 | [diff] [blame] | 569 | /* |
| 570 | * test for negative offset, only if we are |
| 571 | * currently scheduled to take the fast |
| 572 | * path. this will update the flags so that |
| 573 | * the slowpath instruction are ignored if the |
| 574 | * offset is negative. |
| 575 | * |
| 576 | * for loard_order == 0 the HI condition will |
| 577 | * make loads at offset 0 take the slow path too. |
| 578 | */ |
| 579 | _emit(condt, ARM_CMP_I(r_off, 0), ctx); |
| 580 | |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 581 | _emit(condt, ARM_ADD_R(r_scratch, r_off, r_skb_data), |
| 582 | ctx); |
| 583 | |
| 584 | if (load_order == 0) |
| 585 | _emit(condt, ARM_LDRB_I(r_A, r_scratch, 0), |
| 586 | ctx); |
| 587 | else if (load_order == 1) |
| 588 | emit_load_be16(condt, r_A, r_scratch, ctx); |
| 589 | else if (load_order == 2) |
| 590 | emit_load_be32(condt, r_A, r_scratch, ctx); |
| 591 | |
| 592 | _emit(condt, ARM_B(b_imm(i + 1, ctx)), ctx); |
| 593 | |
| 594 | /* the slowpath */ |
| 595 | emit_mov_i(ARM_R3, (u32)load_func[load_order], ctx); |
| 596 | emit(ARM_MOV_R(ARM_R0, r_skb), ctx); |
| 597 | /* the offset is already in R1 */ |
| 598 | emit_blx_r(ARM_R3, ctx); |
| 599 | /* check the result of skb_copy_bits */ |
| 600 | emit(ARM_CMP_I(ARM_R1, 0), ctx); |
| 601 | emit_err_ret(ARM_COND_NE, ctx); |
| 602 | emit(ARM_MOV_R(r_A, ARM_R0), ctx); |
| 603 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 604 | case BPF_LD | BPF_W | BPF_IND: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 605 | load_order = 2; |
| 606 | goto load_ind; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 607 | case BPF_LD | BPF_H | BPF_IND: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 608 | load_order = 1; |
| 609 | goto load_ind; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 610 | case BPF_LD | BPF_B | BPF_IND: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 611 | load_order = 0; |
| 612 | load_ind: |
Nicolas Schichan | 8690f47 | 2015-10-02 15:39:12 +0200 | [diff] [blame] | 613 | update_on_xread(ctx); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 614 | OP_IMM3(ARM_ADD, r_off, r_X, k, ctx); |
| 615 | goto load_common; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 616 | case BPF_LDX | BPF_IMM: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 617 | ctx->seen |= SEEN_X; |
| 618 | emit_mov_i(r_X, k, ctx); |
| 619 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 620 | case BPF_LDX | BPF_W | BPF_LEN: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 621 | ctx->seen |= SEEN_X | SEEN_SKB; |
| 622 | emit(ARM_LDR_I(r_X, r_skb, |
| 623 | offsetof(struct sk_buff, len)), ctx); |
| 624 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 625 | case BPF_LDX | BPF_MEM: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 626 | ctx->seen |= SEEN_X | SEEN_MEM_WORD(k); |
| 627 | emit(ARM_LDR_I(r_X, ARM_SP, SCRATCH_OFF(k)), ctx); |
| 628 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 629 | case BPF_LDX | BPF_B | BPF_MSH: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 630 | /* x = ((*(frame + k)) & 0xf) << 2; */ |
| 631 | ctx->seen |= SEEN_X | SEEN_DATA | SEEN_CALL; |
| 632 | /* the interpreter should deal with the negative K */ |
Chen Gang | 45549a6 | 2013-03-10 10:15:54 +0800 | [diff] [blame] | 633 | if ((int)k < 0) |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 634 | return -1; |
| 635 | /* offset in r1: we might have to take the slow path */ |
| 636 | emit_mov_i(r_off, k, ctx); |
| 637 | emit(ARM_CMP_R(r_skb_hl, r_off), ctx); |
| 638 | |
| 639 | /* load in r0: common with the slowpath */ |
| 640 | _emit(ARM_COND_HI, ARM_LDRB_R(ARM_R0, r_skb_data, |
| 641 | ARM_R1), ctx); |
| 642 | /* |
| 643 | * emit_mov_i() might generate one or two instructions, |
| 644 | * the same holds for emit_blx_r() |
| 645 | */ |
| 646 | _emit(ARM_COND_HI, ARM_B(b_imm(i + 1, ctx) - 2), ctx); |
| 647 | |
| 648 | emit(ARM_MOV_R(ARM_R0, r_skb), ctx); |
| 649 | /* r_off is r1 */ |
| 650 | emit_mov_i(ARM_R3, (u32)jit_get_skb_b, ctx); |
| 651 | emit_blx_r(ARM_R3, ctx); |
| 652 | /* check the return value of skb_copy_bits */ |
| 653 | emit(ARM_CMP_I(ARM_R1, 0), ctx); |
| 654 | emit_err_ret(ARM_COND_NE, ctx); |
| 655 | |
| 656 | emit(ARM_AND_I(r_X, ARM_R0, 0x00f), ctx); |
| 657 | emit(ARM_LSL_I(r_X, r_X, 2), ctx); |
| 658 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 659 | case BPF_ST: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 660 | ctx->seen |= SEEN_MEM_WORD(k); |
| 661 | emit(ARM_STR_I(r_A, ARM_SP, SCRATCH_OFF(k)), ctx); |
| 662 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 663 | case BPF_STX: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 664 | update_on_xread(ctx); |
| 665 | ctx->seen |= SEEN_MEM_WORD(k); |
| 666 | emit(ARM_STR_I(r_X, ARM_SP, SCRATCH_OFF(k)), ctx); |
| 667 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 668 | case BPF_ALU | BPF_ADD | BPF_K: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 669 | /* A += K */ |
| 670 | OP_IMM3(ARM_ADD, r_A, r_A, k, ctx); |
| 671 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 672 | case BPF_ALU | BPF_ADD | BPF_X: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 673 | update_on_xread(ctx); |
| 674 | emit(ARM_ADD_R(r_A, r_A, r_X), ctx); |
| 675 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 676 | case BPF_ALU | BPF_SUB | BPF_K: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 677 | /* A -= K */ |
| 678 | OP_IMM3(ARM_SUB, r_A, r_A, k, ctx); |
| 679 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 680 | case BPF_ALU | BPF_SUB | BPF_X: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 681 | update_on_xread(ctx); |
| 682 | emit(ARM_SUB_R(r_A, r_A, r_X), ctx); |
| 683 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 684 | case BPF_ALU | BPF_MUL | BPF_K: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 685 | /* A *= K */ |
| 686 | emit_mov_i(r_scratch, k, ctx); |
| 687 | emit(ARM_MUL(r_A, r_A, r_scratch), ctx); |
| 688 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 689 | case BPF_ALU | BPF_MUL | BPF_X: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 690 | update_on_xread(ctx); |
| 691 | emit(ARM_MUL(r_A, r_A, r_X), ctx); |
| 692 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 693 | case BPF_ALU | BPF_DIV | BPF_K: |
Eric Dumazet | aee636c | 2014-01-15 06:50:07 -0800 | [diff] [blame] | 694 | if (k == 1) |
| 695 | break; |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 696 | emit_mov_i(r_scratch, k, ctx); |
Nicolas Schichan | 4560cdf | 2015-10-02 17:06:47 +0200 | [diff] [blame] | 697 | emit_udivmod(r_A, r_A, r_scratch, ctx, BPF_DIV); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 698 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 699 | case BPF_ALU | BPF_DIV | BPF_X: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 700 | update_on_xread(ctx); |
| 701 | emit(ARM_CMP_I(r_X, 0), ctx); |
| 702 | emit_err_ret(ARM_COND_EQ, ctx); |
Nicolas Schichan | 4560cdf | 2015-10-02 17:06:47 +0200 | [diff] [blame] | 703 | emit_udivmod(r_A, r_A, r_X, ctx, BPF_DIV); |
| 704 | break; |
| 705 | case BPF_ALU | BPF_MOD | BPF_K: |
| 706 | if (k == 1) { |
| 707 | emit_mov_i(r_A, 0, ctx); |
| 708 | break; |
| 709 | } |
| 710 | emit_mov_i(r_scratch, k, ctx); |
| 711 | emit_udivmod(r_A, r_A, r_scratch, ctx, BPF_MOD); |
| 712 | break; |
| 713 | case BPF_ALU | BPF_MOD | BPF_X: |
| 714 | update_on_xread(ctx); |
| 715 | emit(ARM_CMP_I(r_X, 0), ctx); |
| 716 | emit_err_ret(ARM_COND_EQ, ctx); |
| 717 | emit_udivmod(r_A, r_A, r_X, ctx, BPF_MOD); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 718 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 719 | case BPF_ALU | BPF_OR | BPF_K: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 720 | /* A |= K */ |
| 721 | OP_IMM3(ARM_ORR, r_A, r_A, k, ctx); |
| 722 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 723 | case BPF_ALU | BPF_OR | BPF_X: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 724 | update_on_xread(ctx); |
| 725 | emit(ARM_ORR_R(r_A, r_A, r_X), ctx); |
| 726 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 727 | case BPF_ALU | BPF_XOR | BPF_K: |
Daniel Borkmann | 3cbe204 | 2012-11-07 15:28:28 +0000 | [diff] [blame] | 728 | /* A ^= K; */ |
| 729 | OP_IMM3(ARM_EOR, r_A, r_A, k, ctx); |
| 730 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 731 | case BPF_ANC | SKF_AD_ALU_XOR_X: |
| 732 | case BPF_ALU | BPF_XOR | BPF_X: |
Daniel Borkmann | 3cbe204 | 2012-11-07 15:28:28 +0000 | [diff] [blame] | 733 | /* A ^= X */ |
| 734 | update_on_xread(ctx); |
| 735 | emit(ARM_EOR_R(r_A, r_A, r_X), ctx); |
| 736 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 737 | case BPF_ALU | BPF_AND | BPF_K: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 738 | /* A &= K */ |
| 739 | OP_IMM3(ARM_AND, r_A, r_A, k, ctx); |
| 740 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 741 | case BPF_ALU | BPF_AND | BPF_X: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 742 | update_on_xread(ctx); |
| 743 | emit(ARM_AND_R(r_A, r_A, r_X), ctx); |
| 744 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 745 | case BPF_ALU | BPF_LSH | BPF_K: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 746 | if (unlikely(k > 31)) |
| 747 | return -1; |
| 748 | emit(ARM_LSL_I(r_A, r_A, k), ctx); |
| 749 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 750 | case BPF_ALU | BPF_LSH | BPF_X: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 751 | update_on_xread(ctx); |
| 752 | emit(ARM_LSL_R(r_A, r_A, r_X), ctx); |
| 753 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 754 | case BPF_ALU | BPF_RSH | BPF_K: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 755 | if (unlikely(k > 31)) |
| 756 | return -1; |
Rabin Vincent | f941461 | 2016-01-05 18:34:04 +0100 | [diff] [blame] | 757 | if (k) |
| 758 | emit(ARM_LSR_I(r_A, r_A, k), ctx); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 759 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 760 | case BPF_ALU | BPF_RSH | BPF_X: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 761 | update_on_xread(ctx); |
| 762 | emit(ARM_LSR_R(r_A, r_A, r_X), ctx); |
| 763 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 764 | case BPF_ALU | BPF_NEG: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 765 | /* A = -A */ |
| 766 | emit(ARM_RSB_I(r_A, r_A, 0), ctx); |
| 767 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 768 | case BPF_JMP | BPF_JA: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 769 | /* pc += K */ |
| 770 | emit(ARM_B(b_imm(i + k + 1, ctx)), ctx); |
| 771 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 772 | case BPF_JMP | BPF_JEQ | BPF_K: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 773 | /* pc += (A == K) ? pc->jt : pc->jf */ |
| 774 | condt = ARM_COND_EQ; |
| 775 | goto cmp_imm; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 776 | case BPF_JMP | BPF_JGT | BPF_K: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 777 | /* pc += (A > K) ? pc->jt : pc->jf */ |
| 778 | condt = ARM_COND_HI; |
| 779 | goto cmp_imm; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 780 | case BPF_JMP | BPF_JGE | BPF_K: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 781 | /* pc += (A >= K) ? pc->jt : pc->jf */ |
| 782 | condt = ARM_COND_HS; |
| 783 | cmp_imm: |
| 784 | imm12 = imm8m(k); |
| 785 | if (imm12 < 0) { |
| 786 | emit_mov_i_no8m(r_scratch, k, ctx); |
| 787 | emit(ARM_CMP_R(r_A, r_scratch), ctx); |
| 788 | } else { |
| 789 | emit(ARM_CMP_I(r_A, imm12), ctx); |
| 790 | } |
| 791 | cond_jump: |
| 792 | if (inst->jt) |
| 793 | _emit(condt, ARM_B(b_imm(i + inst->jt + 1, |
| 794 | ctx)), ctx); |
| 795 | if (inst->jf) |
| 796 | _emit(condt ^ 1, ARM_B(b_imm(i + inst->jf + 1, |
| 797 | ctx)), ctx); |
| 798 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 799 | case BPF_JMP | BPF_JEQ | BPF_X: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 800 | /* pc += (A == X) ? pc->jt : pc->jf */ |
| 801 | condt = ARM_COND_EQ; |
| 802 | goto cmp_x; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 803 | case BPF_JMP | BPF_JGT | BPF_X: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 804 | /* pc += (A > X) ? pc->jt : pc->jf */ |
| 805 | condt = ARM_COND_HI; |
| 806 | goto cmp_x; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 807 | case BPF_JMP | BPF_JGE | BPF_X: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 808 | /* pc += (A >= X) ? pc->jt : pc->jf */ |
| 809 | condt = ARM_COND_CS; |
| 810 | cmp_x: |
| 811 | update_on_xread(ctx); |
| 812 | emit(ARM_CMP_R(r_A, r_X), ctx); |
| 813 | goto cond_jump; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 814 | case BPF_JMP | BPF_JSET | BPF_K: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 815 | /* pc += (A & K) ? pc->jt : pc->jf */ |
| 816 | condt = ARM_COND_NE; |
| 817 | /* not set iff all zeroes iff Z==1 iff EQ */ |
| 818 | |
| 819 | imm12 = imm8m(k); |
| 820 | if (imm12 < 0) { |
| 821 | emit_mov_i_no8m(r_scratch, k, ctx); |
| 822 | emit(ARM_TST_R(r_A, r_scratch), ctx); |
| 823 | } else { |
| 824 | emit(ARM_TST_I(r_A, imm12), ctx); |
| 825 | } |
| 826 | goto cond_jump; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 827 | case BPF_JMP | BPF_JSET | BPF_X: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 828 | /* pc += (A & X) ? pc->jt : pc->jf */ |
| 829 | update_on_xread(ctx); |
| 830 | condt = ARM_COND_NE; |
| 831 | emit(ARM_TST_R(r_A, r_X), ctx); |
| 832 | goto cond_jump; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 833 | case BPF_RET | BPF_A: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 834 | emit(ARM_MOV_R(ARM_R0, r_A), ctx); |
| 835 | goto b_epilogue; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 836 | case BPF_RET | BPF_K: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 837 | if ((k == 0) && (ctx->ret0_fp_idx < 0)) |
| 838 | ctx->ret0_fp_idx = i; |
| 839 | emit_mov_i(ARM_R0, k, ctx); |
| 840 | b_epilogue: |
| 841 | if (i != ctx->skf->len - 1) |
| 842 | emit(ARM_B(b_imm(prog->len, ctx)), ctx); |
| 843 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 844 | case BPF_MISC | BPF_TAX: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 845 | /* X = A */ |
| 846 | ctx->seen |= SEEN_X; |
| 847 | emit(ARM_MOV_R(r_X, r_A), ctx); |
| 848 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 849 | case BPF_MISC | BPF_TXA: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 850 | /* A = X */ |
| 851 | update_on_xread(ctx); |
| 852 | emit(ARM_MOV_R(r_A, r_X), ctx); |
| 853 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 854 | case BPF_ANC | SKF_AD_PROTOCOL: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 855 | /* A = ntohs(skb->protocol) */ |
| 856 | ctx->seen |= SEEN_SKB; |
| 857 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, |
| 858 | protocol) != 2); |
| 859 | off = offsetof(struct sk_buff, protocol); |
| 860 | emit(ARM_LDRH_I(r_scratch, r_skb, off), ctx); |
| 861 | emit_swap16(r_A, r_scratch, ctx); |
| 862 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 863 | case BPF_ANC | SKF_AD_CPU: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 864 | /* r_scratch = current_thread_info() */ |
| 865 | OP_IMM3(ARM_BIC, r_scratch, ARM_SP, THREAD_SIZE - 1, ctx); |
| 866 | /* A = current_thread_info()->cpu */ |
| 867 | BUILD_BUG_ON(FIELD_SIZEOF(struct thread_info, cpu) != 4); |
| 868 | off = offsetof(struct thread_info, cpu); |
| 869 | emit(ARM_LDR_I(r_A, r_scratch, off), ctx); |
| 870 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 871 | case BPF_ANC | SKF_AD_IFINDEX: |
Nicolas Schichan | 5bf705b | 2015-07-27 15:06:51 +0200 | [diff] [blame] | 872 | case BPF_ANC | SKF_AD_HATYPE: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 873 | /* A = skb->dev->ifindex */ |
Nicolas Schichan | 5bf705b | 2015-07-27 15:06:51 +0200 | [diff] [blame] | 874 | /* A = skb->dev->type */ |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 875 | ctx->seen |= SEEN_SKB; |
| 876 | off = offsetof(struct sk_buff, dev); |
| 877 | emit(ARM_LDR_I(r_scratch, r_skb, off), ctx); |
| 878 | |
| 879 | emit(ARM_CMP_I(r_scratch, 0), ctx); |
| 880 | emit_err_ret(ARM_COND_EQ, ctx); |
| 881 | |
| 882 | BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, |
| 883 | ifindex) != 4); |
Nicolas Schichan | 5bf705b | 2015-07-27 15:06:51 +0200 | [diff] [blame] | 884 | BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, |
| 885 | type) != 2); |
| 886 | |
| 887 | if (code == (BPF_ANC | SKF_AD_IFINDEX)) { |
| 888 | off = offsetof(struct net_device, ifindex); |
| 889 | emit(ARM_LDR_I(r_A, r_scratch, off), ctx); |
| 890 | } else { |
| 891 | /* |
| 892 | * offset of field "type" in "struct |
| 893 | * net_device" is above what can be |
| 894 | * used in the ldrh rd, [rn, #imm] |
| 895 | * instruction, so load the offset in |
| 896 | * a register and use ldrh rd, [rn, rm] |
| 897 | */ |
| 898 | off = offsetof(struct net_device, type); |
| 899 | emit_mov_i(ARM_R3, off, ctx); |
| 900 | emit(ARM_LDRH_R(r_A, r_scratch, ARM_R3), ctx); |
| 901 | } |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 902 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 903 | case BPF_ANC | SKF_AD_MARK: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 904 | ctx->seen |= SEEN_SKB; |
| 905 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); |
| 906 | off = offsetof(struct sk_buff, mark); |
| 907 | emit(ARM_LDR_I(r_A, r_skb, off), ctx); |
| 908 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 909 | case BPF_ANC | SKF_AD_RXHASH: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 910 | ctx->seen |= SEEN_SKB; |
Tom Herbert | 61b905d | 2014-03-24 15:34:47 -0700 | [diff] [blame] | 911 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4); |
| 912 | off = offsetof(struct sk_buff, hash); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 913 | emit(ARM_LDR_I(r_A, r_skb, off), ctx); |
| 914 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 915 | case BPF_ANC | SKF_AD_VLAN_TAG: |
| 916 | case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT: |
Daniel Borkmann | bf0098f | 2012-11-07 15:31:02 +0000 | [diff] [blame] | 917 | ctx->seen |= SEEN_SKB; |
| 918 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2); |
| 919 | off = offsetof(struct sk_buff, vlan_tci); |
| 920 | emit(ARM_LDRH_I(r_A, r_skb, off), ctx); |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 921 | if (code == (BPF_ANC | SKF_AD_VLAN_TAG)) |
Nicolas Schichan | c18fe54 | 2015-07-21 14:14:14 +0200 | [diff] [blame] | 922 | OP_IMM3(ARM_AND, r_A, r_A, ~VLAN_TAG_PRESENT, ctx); |
| 923 | else { |
| 924 | OP_IMM3(ARM_LSR, r_A, r_A, 12, ctx); |
| 925 | OP_IMM3(ARM_AND, r_A, r_A, 0x1, ctx); |
| 926 | } |
Daniel Borkmann | bf0098f | 2012-11-07 15:31:02 +0000 | [diff] [blame] | 927 | break; |
Nicolas Schichan | 1447f93 | 2015-07-27 15:06:49 +0200 | [diff] [blame] | 928 | case BPF_ANC | SKF_AD_PKTTYPE: |
| 929 | ctx->seen |= SEEN_SKB; |
| 930 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, |
| 931 | __pkt_type_offset[0]) != 1); |
| 932 | off = PKT_TYPE_OFFSET(); |
| 933 | emit(ARM_LDRB_I(r_A, r_skb, off), ctx); |
| 934 | emit(ARM_AND_I(r_A, r_A, PKT_TYPE_MAX), ctx); |
| 935 | #ifdef __BIG_ENDIAN_BITFIELD |
| 936 | emit(ARM_LSR_I(r_A, r_A, 5), ctx); |
| 937 | #endif |
| 938 | break; |
Daniel Borkmann | 3480593 | 2014-05-29 10:22:50 +0200 | [diff] [blame] | 939 | case BPF_ANC | SKF_AD_QUEUE: |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 940 | ctx->seen |= SEEN_SKB; |
| 941 | BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, |
| 942 | queue_mapping) != 2); |
| 943 | BUILD_BUG_ON(offsetof(struct sk_buff, |
| 944 | queue_mapping) > 0xff); |
| 945 | off = offsetof(struct sk_buff, queue_mapping); |
| 946 | emit(ARM_LDRH_I(r_A, r_skb, off), ctx); |
| 947 | break; |
Nicolas Schichan | 303249a | 2015-07-27 15:06:50 +0200 | [diff] [blame] | 948 | case BPF_ANC | SKF_AD_PAY_OFFSET: |
| 949 | ctx->seen |= SEEN_SKB | SEEN_CALL; |
| 950 | |
| 951 | emit(ARM_MOV_R(ARM_R0, r_skb), ctx); |
| 952 | emit_mov_i(ARM_R3, (unsigned int)skb_get_poff, ctx); |
| 953 | emit_blx_r(ARM_R3, ctx); |
| 954 | emit(ARM_MOV_R(r_A, ARM_R0), ctx); |
| 955 | break; |
Nicolas Schichan | 24e737c | 2015-05-07 15:00:13 +0200 | [diff] [blame] | 956 | case BPF_LDX | BPF_W | BPF_ABS: |
| 957 | /* |
| 958 | * load a 32bit word from struct seccomp_data. |
| 959 | * seccomp_check_filter() will already have checked |
| 960 | * that k is 32bit aligned and lies within the |
| 961 | * struct seccomp_data. |
| 962 | */ |
| 963 | ctx->seen |= SEEN_SKB; |
| 964 | emit(ARM_LDR_I(r_A, r_skb, k), ctx); |
| 965 | break; |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 966 | default: |
| 967 | return -1; |
| 968 | } |
Nicolas Schichan | 0b59d88 | 2015-05-07 17:14:21 +0200 | [diff] [blame] | 969 | |
| 970 | if (ctx->flags & FLAG_IMM_OVERFLOW) |
| 971 | /* |
| 972 | * this instruction generated an overflow when |
| 973 | * trying to access the literal pool, so |
| 974 | * delegate this filter to the kernel interpreter. |
| 975 | */ |
| 976 | return -1; |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 977 | } |
| 978 | |
| 979 | /* compute offsets only during the first pass */ |
| 980 | if (ctx->target == NULL) |
| 981 | ctx->offsets[i] = ctx->idx * 4; |
| 982 | |
| 983 | return 0; |
| 984 | } |
| 985 | |
| 986 | |
Alexei Starovoitov | 7ae457c | 2014-07-30 20:34:16 -0700 | [diff] [blame] | 987 | void bpf_jit_compile(struct bpf_prog *fp) |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 988 | { |
Daniel Borkmann | 55309dd | 2014-09-08 08:04:48 +0200 | [diff] [blame] | 989 | struct bpf_binary_header *header; |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 990 | struct jit_ctx ctx; |
| 991 | unsigned tmp_idx; |
| 992 | unsigned alloc_size; |
Daniel Borkmann | 55309dd | 2014-09-08 08:04:48 +0200 | [diff] [blame] | 993 | u8 *target_ptr; |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 994 | |
| 995 | if (!bpf_jit_enable) |
| 996 | return; |
| 997 | |
| 998 | memset(&ctx, 0, sizeof(ctx)); |
| 999 | ctx.skf = fp; |
| 1000 | ctx.ret0_fp_idx = -1; |
| 1001 | |
Schichan Nicolas | 89c2e00 | 2012-12-10 14:49:39 +0100 | [diff] [blame] | 1002 | ctx.offsets = kzalloc(4 * (ctx.skf->len + 1), GFP_KERNEL); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 1003 | if (ctx.offsets == NULL) |
| 1004 | return; |
| 1005 | |
| 1006 | /* fake pass to fill in the ctx->seen */ |
| 1007 | if (unlikely(build_body(&ctx))) |
| 1008 | goto out; |
| 1009 | |
| 1010 | tmp_idx = ctx.idx; |
| 1011 | build_prologue(&ctx); |
| 1012 | ctx.prologue_bytes = (ctx.idx - tmp_idx) * 4; |
| 1013 | |
| 1014 | #if __LINUX_ARM_ARCH__ < 7 |
| 1015 | tmp_idx = ctx.idx; |
| 1016 | build_epilogue(&ctx); |
| 1017 | ctx.epilogue_bytes = (ctx.idx - tmp_idx) * 4; |
| 1018 | |
| 1019 | ctx.idx += ctx.imm_count; |
| 1020 | if (ctx.imm_count) { |
Schichan Nicolas | 89c2e00 | 2012-12-10 14:49:39 +0100 | [diff] [blame] | 1021 | ctx.imms = kzalloc(4 * ctx.imm_count, GFP_KERNEL); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 1022 | if (ctx.imms == NULL) |
| 1023 | goto out; |
| 1024 | } |
| 1025 | #else |
| 1026 | /* there's nothing after the epilogue on ARMv7 */ |
| 1027 | build_epilogue(&ctx); |
| 1028 | #endif |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 1029 | alloc_size = 4 * ctx.idx; |
Daniel Borkmann | 55309dd | 2014-09-08 08:04:48 +0200 | [diff] [blame] | 1030 | header = bpf_jit_binary_alloc(alloc_size, &target_ptr, |
| 1031 | 4, jit_fill_hole); |
| 1032 | if (header == NULL) |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 1033 | goto out; |
| 1034 | |
Daniel Borkmann | 55309dd | 2014-09-08 08:04:48 +0200 | [diff] [blame] | 1035 | ctx.target = (u32 *) target_ptr; |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 1036 | ctx.idx = 0; |
Daniel Borkmann | 55309dd | 2014-09-08 08:04:48 +0200 | [diff] [blame] | 1037 | |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 1038 | build_prologue(&ctx); |
Nicolas Schichan | 0b59d88 | 2015-05-07 17:14:21 +0200 | [diff] [blame] | 1039 | if (build_body(&ctx) < 0) { |
| 1040 | #if __LINUX_ARM_ARCH__ < 7 |
| 1041 | if (ctx.imm_count) |
| 1042 | kfree(ctx.imms); |
| 1043 | #endif |
| 1044 | bpf_jit_binary_free(header); |
| 1045 | goto out; |
| 1046 | } |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 1047 | build_epilogue(&ctx); |
| 1048 | |
Daniel Borkmann | ebaef64 | 2015-11-14 01:26:53 +0100 | [diff] [blame] | 1049 | flush_icache_range((u32)header, (u32)(ctx.target + ctx.idx)); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 1050 | |
| 1051 | #if __LINUX_ARM_ARCH__ < 7 |
| 1052 | if (ctx.imm_count) |
| 1053 | kfree(ctx.imms); |
| 1054 | #endif |
| 1055 | |
| 1056 | if (bpf_jit_enable > 1) |
Daniel Borkmann | 7961780 | 2013-03-21 22:22:03 +0100 | [diff] [blame] | 1057 | /* there are 2 passes here */ |
| 1058 | bpf_jit_dump(fp->len, alloc_size, 2, ctx.target); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 1059 | |
Daniel Borkmann | 55309dd | 2014-09-08 08:04:48 +0200 | [diff] [blame] | 1060 | set_memory_ro((unsigned long)header, header->pages); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 1061 | fp->bpf_func = (void *)ctx.target; |
Daniel Borkmann | a91263d | 2015-09-30 01:41:50 +0200 | [diff] [blame] | 1062 | fp->jited = 1; |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 1063 | out: |
| 1064 | kfree(ctx.offsets); |
| 1065 | return; |
| 1066 | } |
| 1067 | |
Alexei Starovoitov | 7ae457c | 2014-07-30 20:34:16 -0700 | [diff] [blame] | 1068 | void bpf_jit_free(struct bpf_prog *fp) |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 1069 | { |
Daniel Borkmann | 55309dd | 2014-09-08 08:04:48 +0200 | [diff] [blame] | 1070 | unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK; |
| 1071 | struct bpf_binary_header *header = (void *)addr; |
Daniel Borkmann | 60a3b22 | 2014-09-02 22:53:44 +0200 | [diff] [blame] | 1072 | |
Daniel Borkmann | 55309dd | 2014-09-08 08:04:48 +0200 | [diff] [blame] | 1073 | if (!fp->jited) |
| 1074 | goto free_filter; |
| 1075 | |
| 1076 | set_memory_rw(addr, header->pages); |
| 1077 | bpf_jit_binary_free(header); |
| 1078 | |
| 1079 | free_filter: |
Daniel Borkmann | 60a3b22 | 2014-09-02 22:53:44 +0200 | [diff] [blame] | 1080 | bpf_prog_unlock_free(fp); |
Mircea Gherzan | ddecdfc | 2012-03-16 13:37:12 +0100 | [diff] [blame] | 1081 | } |