1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Just-In-Time compiler for eBPF filters on 32bit ARM 4 * 5 * Copyright (c) 2017 Shubham Bansal <illusionist.neo@gmail.com> 6 * Copyright (c) 2011 Mircea Gherzan <mgherzan@gmail.com> 7 */ 8 9 #include <linux/bpf.h> 10 #include <linux/bitops.h> 11 #include <linux/compiler.h> 12 #include <linux/errno.h> 13 #include <linux/filter.h> 14 #include <linux/netdevice.h> 15 #include <linux/string.h> 16 #include <linux/slab.h> 17 #include <linux/if_vlan.h> 18 19 #include <asm/cacheflush.h> 20 #include <asm/hwcap.h> 21 #include <asm/opcodes.h> 22 #include <asm/system_info.h> 23 24 #include "bpf_jit_32.h" 25 26 /* 27 * eBPF prog stack layout: 28 * 29 * high 30 * original ARM_SP => +-----+ 31 * | | callee saved registers 32 * +-----+ <= (BPF_FP + SCRATCH_SIZE) 33 * | ... | eBPF JIT scratch space 34 * eBPF fp register => +-----+ 35 * (BPF_FP) | ... | eBPF prog stack 36 * +-----+ 37 * |RSVD | JIT scratchpad 38 * current ARM_SP => +-----+ <= (BPF_FP - STACK_SIZE + SCRATCH_SIZE) 39 * | | 40 * | ... | Function call stack 41 * | | 42 * +-----+ 43 * low 44 * 45 * The callee saved registers depends on whether frame pointers are enabled. 46 * With frame pointers (to be compliant with the ABI): 47 * 48 * high 49 * original ARM_SP => +--------------+ \ 50 * | pc | | 51 * current ARM_FP => +--------------+ } callee saved registers 52 * |r4-r9,fp,ip,lr| | 53 * +--------------+ / 54 * low 55 * 56 * Without frame pointers: 57 * 58 * high 59 * original ARM_SP => +--------------+ 60 * | r4-r9,fp,lr | callee saved registers 61 * current ARM_FP => +--------------+ 62 * low 63 * 64 * When popping registers off the stack at the end of a BPF function, we 65 * reference them via the current ARM_FP register. 66 */ 67 #define CALLEE_MASK (1 << ARM_R4 | 1 << ARM_R5 | 1 << ARM_R6 | \ 68 1 << ARM_R7 | 1 << ARM_R8 | 1 << ARM_R9 | \ 69 1 << ARM_FP) 70 #define CALLEE_PUSH_MASK (CALLEE_MASK | 1 << ARM_LR) 71 #define CALLEE_POP_MASK (CALLEE_MASK | 1 << ARM_PC) 72 73 enum { 74 /* Stack layout - these are offsets from (top of stack - 4) */ 75 BPF_R2_HI, 76 BPF_R2_LO, 77 BPF_R3_HI, 78 BPF_R3_LO, 79 BPF_R4_HI, 80 BPF_R4_LO, 81 BPF_R5_HI, 82 BPF_R5_LO, 83 BPF_R7_HI, 84 BPF_R7_LO, 85 BPF_R8_HI, 86 BPF_R8_LO, 87 BPF_R9_HI, 88 BPF_R9_LO, 89 BPF_FP_HI, 90 BPF_FP_LO, 91 BPF_TC_HI, 92 BPF_TC_LO, 93 BPF_AX_HI, 94 BPF_AX_LO, 95 /* Stack space for BPF_REG_2, BPF_REG_3, BPF_REG_4, 96 * BPF_REG_5, BPF_REG_7, BPF_REG_8, BPF_REG_9, 97 * BPF_REG_FP and Tail call counts. 98 */ 99 BPF_JIT_SCRATCH_REGS, 100 }; 101 102 /* 103 * Negative "register" values indicate the register is stored on the stack 104 * and are the offset from the top of the eBPF JIT scratch space. 105 */ 106 #define STACK_OFFSET(k) (-4 - (k) * 4) 107 #define SCRATCH_SIZE (BPF_JIT_SCRATCH_REGS * 4) 108 109 #ifdef CONFIG_FRAME_POINTER 110 #define EBPF_SCRATCH_TO_ARM_FP(x) ((x) - 4 * hweight16(CALLEE_PUSH_MASK) - 4) 111 #else 112 #define EBPF_SCRATCH_TO_ARM_FP(x) (x) 113 #endif 114 115 #define TMP_REG_1 (MAX_BPF_JIT_REG + 0) /* TEMP Register 1 */ 116 #define TMP_REG_2 (MAX_BPF_JIT_REG + 1) /* TEMP Register 2 */ 117 #define TCALL_CNT (MAX_BPF_JIT_REG + 2) /* Tail Call Count */ 118 119 #define FLAG_IMM_OVERFLOW (1 << 0) 120 121 /* 122 * Map eBPF registers to ARM 32bit registers or stack scratch space. 123 * 124 * 1. First argument is passed using the arm 32bit registers and rest of the 125 * arguments are passed on stack scratch space. 126 * 2. First callee-saved argument is mapped to arm 32 bit registers and rest 127 * arguments are mapped to scratch space on stack. 128 * 3. We need two 64 bit temp registers to do complex operations on eBPF 129 * registers. 130 * 131 * As the eBPF registers are all 64 bit registers and arm has only 32 bit 132 * registers, we have to map each eBPF registers with two arm 32 bit regs or 133 * scratch memory space and we have to build eBPF 64 bit register from those. 134 * 135 */ 136 static const s8 bpf2a32[][2] = { 137 /* return value from in-kernel function, and exit value from eBPF */ 138 [BPF_REG_0] = {ARM_R1, ARM_R0}, 139 /* arguments from eBPF program to in-kernel function */ 140 [BPF_REG_1] = {ARM_R3, ARM_R2}, 141 /* Stored on stack scratch space */ 142 [BPF_REG_2] = {STACK_OFFSET(BPF_R2_HI), STACK_OFFSET(BPF_R2_LO)}, 143 [BPF_REG_3] = {STACK_OFFSET(BPF_R3_HI), STACK_OFFSET(BPF_R3_LO)}, 144 [BPF_REG_4] = {STACK_OFFSET(BPF_R4_HI), STACK_OFFSET(BPF_R4_LO)}, 145 [BPF_REG_5] = {STACK_OFFSET(BPF_R5_HI), STACK_OFFSET(BPF_R5_LO)}, 146 /* callee saved registers that in-kernel function will preserve */ 147 [BPF_REG_6] = {ARM_R5, ARM_R4}, 148 /* Stored on stack scratch space */ 149 [BPF_REG_7] = {STACK_OFFSET(BPF_R7_HI), STACK_OFFSET(BPF_R7_LO)}, 150 [BPF_REG_8] = {STACK_OFFSET(BPF_R8_HI), STACK_OFFSET(BPF_R8_LO)}, 151 [BPF_REG_9] = {STACK_OFFSET(BPF_R9_HI), STACK_OFFSET(BPF_R9_LO)}, 152 /* Read only Frame Pointer to access Stack */ 153 [BPF_REG_FP] = {STACK_OFFSET(BPF_FP_HI), STACK_OFFSET(BPF_FP_LO)}, 154 /* Temporary Register for internal BPF JIT, can be used 155 * for constant blindings and others. 156 */ 157 [TMP_REG_1] = {ARM_R7, ARM_R6}, 158 [TMP_REG_2] = {ARM_R9, ARM_R8}, 159 /* Tail call count. Stored on stack scratch space. */ 160 [TCALL_CNT] = {STACK_OFFSET(BPF_TC_HI), STACK_OFFSET(BPF_TC_LO)}, 161 /* temporary register for blinding constants. 162 * Stored on stack scratch space. 163 */ 164 [BPF_REG_AX] = {STACK_OFFSET(BPF_AX_HI), STACK_OFFSET(BPF_AX_LO)}, 165 }; 166 167 #define dst_lo dst[1] 168 #define dst_hi dst[0] 169 #define src_lo src[1] 170 #define src_hi src[0] 171 172 /* 173 * JIT Context: 174 * 175 * prog : bpf_prog 176 * idx : index of current last JITed instruction. 177 * prologue_bytes : bytes used in prologue. 178 * epilogue_offset : offset of epilogue starting. 179 * offsets : array of eBPF instruction offsets in 180 * JITed code. 181 * target : final JITed code. 182 * epilogue_bytes : no of bytes used in epilogue. 183 * imm_count : no of immediate counts used for global 184 * variables. 185 * imms : array of global variable addresses. 186 */ 187 188 struct jit_ctx { 189 const struct bpf_prog *prog; 190 unsigned int idx; 191 unsigned int prologue_bytes; 192 unsigned int epilogue_offset; 193 unsigned int cpu_architecture; 194 u32 flags; 195 u32 *offsets; 196 u32 *target; 197 u32 stack_size; 198 #if __LINUX_ARM_ARCH__ < 7 199 u16 epilogue_bytes; 200 u16 imm_count; 201 u32 *imms; 202 #endif 203 }; 204 205 /* 206 * Wrappers which handle both OABI and EABI and assures Thumb2 interworking 207 * (where the assembly routines like __aeabi_uidiv could cause problems). 208 */ 209 static u32 jit_udiv32(u32 dividend, u32 divisor) 210 { 211 return dividend / divisor; 212 } 213 214 static u32 jit_mod32(u32 dividend, u32 divisor) 215 { 216 return dividend % divisor; 217 } 218 219 static inline void _emit(int cond, u32 inst, struct jit_ctx *ctx) 220 { 221 inst |= (cond << 28); 222 inst = __opcode_to_mem_arm(inst); 223 224 if (ctx->target != NULL) 225 ctx->target[ctx->idx] = inst; 226 227 ctx->idx++; 228 } 229 230 /* 231 * Emit an instruction that will be executed unconditionally. 232 */ 233 static inline void emit(u32 inst, struct jit_ctx *ctx) 234 { 235 _emit(ARM_COND_AL, inst, ctx); 236 } 237 238 /* 239 * This is rather horrid, but necessary to convert an integer constant 240 * to an immediate operand for the opcodes, and be able to detect at 241 * build time whether the constant can't be converted (iow, usable in 242 * BUILD_BUG_ON()). 243 */ 244 #define imm12val(v, s) (rol32(v, (s)) | (s) << 7) 245 #define const_imm8m(x) \ 246 ({ int r; \ 247 u32 v = (x); \ 248 if (!(v & ~0x000000ff)) \ 249 r = imm12val(v, 0); \ 250 else if (!(v & ~0xc000003f)) \ 251 r = imm12val(v, 2); \ 252 else if (!(v & ~0xf000000f)) \ 253 r = imm12val(v, 4); \ 254 else if (!(v & ~0xfc000003)) \ 255 r = imm12val(v, 6); \ 256 else if (!(v & ~0xff000000)) \ 257 r = imm12val(v, 8); \ 258 else if (!(v & ~0x3fc00000)) \ 259 r = imm12val(v, 10); \ 260 else if (!(v & ~0x0ff00000)) \ 261 r = imm12val(v, 12); \ 262 else if (!(v & ~0x03fc0000)) \ 263 r = imm12val(v, 14); \ 264 else if (!(v & ~0x00ff0000)) \ 265 r = imm12val(v, 16); \ 266 else if (!(v & ~0x003fc000)) \ 267 r = imm12val(v, 18); \ 268 else if (!(v & ~0x000ff000)) \ 269 r = imm12val(v, 20); \ 270 else if (!(v & ~0x0003fc00)) \ 271 r = imm12val(v, 22); \ 272 else if (!(v & ~0x0000ff00)) \ 273 r = imm12val(v, 24); \ 274 else if (!(v & ~0x00003fc0)) \ 275 r = imm12val(v, 26); \ 276 else if (!(v & ~0x00000ff0)) \ 277 r = imm12val(v, 28); \ 278 else if (!(v & ~0x000003fc)) \ 279 r = imm12val(v, 30); \ 280 else \ 281 r = -1; \ 282 r; }) 283 284 /* 285 * Checks if immediate value can be converted to imm12(12 bits) value. 286 */ 287 static int imm8m(u32 x) 288 { 289 u32 rot; 290 291 for (rot = 0; rot < 16; rot++) 292 if ((x & ~ror32(0xff, 2 * rot)) == 0) 293 return rol32(x, 2 * rot) | (rot << 8); 294 return -1; 295 } 296 297 #define imm8m(x) (__builtin_constant_p(x) ? const_imm8m(x) : imm8m(x)) 298 299 static u32 arm_bpf_ldst_imm12(u32 op, u8 rt, u8 rn, s16 imm12) 300 { 301 op |= rt << 12 | rn << 16; 302 if (imm12 >= 0) 303 op |= ARM_INST_LDST__U; 304 else 305 imm12 = -imm12; 306 return op | (imm12 & ARM_INST_LDST__IMM12); 307 } 308 309 static u32 arm_bpf_ldst_imm8(u32 op, u8 rt, u8 rn, s16 imm8) 310 { 311 op |= rt << 12 | rn << 16; 312 if (imm8 >= 0) 313 op |= ARM_INST_LDST__U; 314 else 315 imm8 = -imm8; 316 return op | (imm8 & 0xf0) << 4 | (imm8 & 0x0f); 317 } 318 319 #define ARM_LDR_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_LDR_I, rt, rn, off) 320 #define ARM_LDRB_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_LDRB_I, rt, rn, off) 321 #define ARM_LDRD_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_LDRD_I, rt, rn, off) 322 #define ARM_LDRH_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_LDRH_I, rt, rn, off) 323 324 #define ARM_STR_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_STR_I, rt, rn, off) 325 #define ARM_STRB_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_STRB_I, rt, rn, off) 326 #define ARM_STRD_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_STRD_I, rt, rn, off) 327 #define ARM_STRH_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_STRH_I, rt, rn, off) 328 329 /* 330 * Initializes the JIT space with undefined instructions. 331 */ 332 static void jit_fill_hole(void *area, unsigned int size) 333 { 334 u32 *ptr; 335 /* We are guaranteed to have aligned memory. */ 336 for (ptr = area; size >= sizeof(u32); size -= sizeof(u32)) 337 *ptr++ = __opcode_to_mem_arm(ARM_INST_UDF); 338 } 339 340 #if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) 341 /* EABI requires the stack to be aligned to 64-bit boundaries */ 342 #define STACK_ALIGNMENT 8 343 #else 344 /* Stack must be aligned to 32-bit boundaries */ 345 #define STACK_ALIGNMENT 4 346 #endif 347 348 /* total stack size used in JITed code */ 349 #define _STACK_SIZE (ctx->prog->aux->stack_depth + SCRATCH_SIZE) 350 #define STACK_SIZE ALIGN(_STACK_SIZE, STACK_ALIGNMENT) 351 352 #if __LINUX_ARM_ARCH__ < 7 353 354 static u16 imm_offset(u32 k, struct jit_ctx *ctx) 355 { 356 unsigned int i = 0, offset; 357 u16 imm; 358 359 /* on the "fake" run we just count them (duplicates included) */ 360 if (ctx->target == NULL) { 361 ctx->imm_count++; 362 return 0; 363 } 364 365 while ((i < ctx->imm_count) && ctx->imms[i]) { 366 if (ctx->imms[i] == k) 367 break; 368 i++; 369 } 370 371 if (ctx->imms[i] == 0) 372 ctx->imms[i] = k; 373 374 /* constants go just after the epilogue */ 375 offset = ctx->offsets[ctx->prog->len - 1] * 4; 376 offset += ctx->prologue_bytes; 377 offset += ctx->epilogue_bytes; 378 offset += i * 4; 379 380 ctx->target[offset / 4] = k; 381 382 /* PC in ARM mode == address of the instruction + 8 */ 383 imm = offset - (8 + ctx->idx * 4); 384 385 if (imm & ~0xfff) { 386 /* 387 * literal pool is too far, signal it into flags. we 388 * can only detect it on the second pass unfortunately. 389 */ 390 ctx->flags |= FLAG_IMM_OVERFLOW; 391 return 0; 392 } 393 394 return imm; 395 } 396 397 #endif /* __LINUX_ARM_ARCH__ */ 398 399 static inline int bpf2a32_offset(int bpf_to, int bpf_from, 400 const struct jit_ctx *ctx) { 401 int to, from; 402 403 if (ctx->target == NULL) 404 return 0; 405 to = ctx->offsets[bpf_to]; 406 from = ctx->offsets[bpf_from]; 407 408 return to - from - 1; 409 } 410 411 /* 412 * Move an immediate that's not an imm8m to a core register. 413 */ 414 static inline void emit_mov_i_no8m(const u8 rd, u32 val, struct jit_ctx *ctx) 415 { 416 #if __LINUX_ARM_ARCH__ < 7 417 emit(ARM_LDR_I(rd, ARM_PC, imm_offset(val, ctx)), ctx); 418 #else 419 emit(ARM_MOVW(rd, val & 0xffff), ctx); 420 if (val > 0xffff) 421 emit(ARM_MOVT(rd, val >> 16), ctx); 422 #endif 423 } 424 425 static inline void emit_mov_i(const u8 rd, u32 val, struct jit_ctx *ctx) 426 { 427 int imm12 = imm8m(val); 428 429 if (imm12 >= 0) 430 emit(ARM_MOV_I(rd, imm12), ctx); 431 else 432 emit_mov_i_no8m(rd, val, ctx); 433 } 434 435 static void emit_bx_r(u8 tgt_reg, struct jit_ctx *ctx) 436 { 437 if (elf_hwcap & HWCAP_THUMB) 438 emit(ARM_BX(tgt_reg), ctx); 439 else 440 emit(ARM_MOV_R(ARM_PC, tgt_reg), ctx); 441 } 442 443 static inline void emit_blx_r(u8 tgt_reg, struct jit_ctx *ctx) 444 { 445 #if __LINUX_ARM_ARCH__ < 5 446 emit(ARM_MOV_R(ARM_LR, ARM_PC), ctx); 447 emit_bx_r(tgt_reg, ctx); 448 #else 449 emit(ARM_BLX_R(tgt_reg), ctx); 450 #endif 451 } 452 453 static inline int epilogue_offset(const struct jit_ctx *ctx) 454 { 455 int to, from; 456 /* No need for 1st dummy run */ 457 if (ctx->target == NULL) 458 return 0; 459 to = ctx->epilogue_offset; 460 from = ctx->idx; 461 462 return to - from - 2; 463 } 464 465 static inline void emit_udivmod(u8 rd, u8 rm, u8 rn, struct jit_ctx *ctx, u8 op) 466 { 467 const s8 *tmp = bpf2a32[TMP_REG_1]; 468 469 #if __LINUX_ARM_ARCH__ == 7 470 if (elf_hwcap & HWCAP_IDIVA) { 471 if (op == BPF_DIV) 472 emit(ARM_UDIV(rd, rm, rn), ctx); 473 else { 474 emit(ARM_UDIV(ARM_IP, rm, rn), ctx); 475 emit(ARM_MLS(rd, rn, ARM_IP, rm), ctx); 476 } 477 return; 478 } 479 #endif 480 481 /* 482 * For BPF_ALU | BPF_DIV | BPF_K instructions 483 * As ARM_R1 and ARM_R0 contains 1st argument of bpf 484 * function, we need to save it on caller side to save 485 * it from getting destroyed within callee. 486 * After the return from the callee, we restore ARM_R0 487 * ARM_R1. 488 */ 489 if (rn != ARM_R1) { 490 emit(ARM_MOV_R(tmp[0], ARM_R1), ctx); 491 emit(ARM_MOV_R(ARM_R1, rn), ctx); 492 } 493 if (rm != ARM_R0) { 494 emit(ARM_MOV_R(tmp[1], ARM_R0), ctx); 495 emit(ARM_MOV_R(ARM_R0, rm), ctx); 496 } 497 498 /* Call appropriate function */ 499 emit_mov_i(ARM_IP, op == BPF_DIV ? 500 (u32)jit_udiv32 : (u32)jit_mod32, ctx); 501 emit_blx_r(ARM_IP, ctx); 502 503 /* Save return value */ 504 if (rd != ARM_R0) 505 emit(ARM_MOV_R(rd, ARM_R0), ctx); 506 507 /* Restore ARM_R0 and ARM_R1 */ 508 if (rn != ARM_R1) 509 emit(ARM_MOV_R(ARM_R1, tmp[0]), ctx); 510 if (rm != ARM_R0) 511 emit(ARM_MOV_R(ARM_R0, tmp[1]), ctx); 512 } 513 514 /* Is the translated BPF register on stack? */ 515 static bool is_stacked(s8 reg) 516 { 517 return reg < 0; 518 } 519 520 /* If a BPF register is on the stack (stk is true), load it to the 521 * supplied temporary register and return the temporary register 522 * for subsequent operations, otherwise just use the CPU register. 523 */ 524 static s8 arm_bpf_get_reg32(s8 reg, s8 tmp, struct jit_ctx *ctx) 525 { 526 if (is_stacked(reg)) { 527 emit(ARM_LDR_I(tmp, ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg)), ctx); 528 reg = tmp; 529 } 530 return reg; 531 } 532 533 static const s8 *arm_bpf_get_reg64(const s8 *reg, const s8 *tmp, 534 struct jit_ctx *ctx) 535 { 536 if (is_stacked(reg[1])) { 537 if (__LINUX_ARM_ARCH__ >= 6 || 538 ctx->cpu_architecture >= CPU_ARCH_ARMv5TE) { 539 emit(ARM_LDRD_I(tmp[1], ARM_FP, 540 EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx); 541 } else { 542 emit(ARM_LDR_I(tmp[1], ARM_FP, 543 EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx); 544 emit(ARM_LDR_I(tmp[0], ARM_FP, 545 EBPF_SCRATCH_TO_ARM_FP(reg[0])), ctx); 546 } 547 reg = tmp; 548 } 549 return reg; 550 } 551 552 /* If a BPF register is on the stack (stk is true), save the register 553 * back to the stack. If the source register is not the same, then 554 * move it into the correct register. 555 */ 556 static void arm_bpf_put_reg32(s8 reg, s8 src, struct jit_ctx *ctx) 557 { 558 if (is_stacked(reg)) 559 emit(ARM_STR_I(src, ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg)), ctx); 560 else if (reg != src) 561 emit(ARM_MOV_R(reg, src), ctx); 562 } 563 564 static void arm_bpf_put_reg64(const s8 *reg, const s8 *src, 565 struct jit_ctx *ctx) 566 { 567 if (is_stacked(reg[1])) { 568 if (__LINUX_ARM_ARCH__ >= 6 || 569 ctx->cpu_architecture >= CPU_ARCH_ARMv5TE) { 570 emit(ARM_STRD_I(src[1], ARM_FP, 571 EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx); 572 } else { 573 emit(ARM_STR_I(src[1], ARM_FP, 574 EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx); 575 emit(ARM_STR_I(src[0], ARM_FP, 576 EBPF_SCRATCH_TO_ARM_FP(reg[0])), ctx); 577 } 578 } else { 579 if (reg[1] != src[1]) 580 emit(ARM_MOV_R(reg[1], src[1]), ctx); 581 if (reg[0] != src[0]) 582 emit(ARM_MOV_R(reg[0], src[0]), ctx); 583 } 584 } 585 586 static inline void emit_a32_mov_i(const s8 dst, const u32 val, 587 struct jit_ctx *ctx) 588 { 589 const s8 *tmp = bpf2a32[TMP_REG_1]; 590 591 if (is_stacked(dst)) { 592 emit_mov_i(tmp[1], val, ctx); 593 arm_bpf_put_reg32(dst, tmp[1], ctx); 594 } else { 595 emit_mov_i(dst, val, ctx); 596 } 597 } 598 599 static void emit_a32_mov_i64(const s8 dst[], u64 val, struct jit_ctx *ctx) 600 { 601 const s8 *tmp = bpf2a32[TMP_REG_1]; 602 const s8 *rd = is_stacked(dst_lo) ? tmp : dst; 603 604 emit_mov_i(rd[1], (u32)val, ctx); 605 emit_mov_i(rd[0], val >> 32, ctx); 606 607 arm_bpf_put_reg64(dst, rd, ctx); 608 } 609 610 /* Sign extended move */ 611 static inline void emit_a32_mov_se_i64(const bool is64, const s8 dst[], 612 const u32 val, struct jit_ctx *ctx) { 613 u64 val64 = val; 614 615 if (is64 && (val & (1<<31))) 616 val64 |= 0xffffffff00000000ULL; 617 emit_a32_mov_i64(dst, val64, ctx); 618 } 619 620 static inline void emit_a32_add_r(const u8 dst, const u8 src, 621 const bool is64, const bool hi, 622 struct jit_ctx *ctx) { 623 /* 64 bit : 624 * adds dst_lo, dst_lo, src_lo 625 * adc dst_hi, dst_hi, src_hi 626 * 32 bit : 627 * add dst_lo, dst_lo, src_lo 628 */ 629 if (!hi && is64) 630 emit(ARM_ADDS_R(dst, dst, src), ctx); 631 else if (hi && is64) 632 emit(ARM_ADC_R(dst, dst, src), ctx); 633 else 634 emit(ARM_ADD_R(dst, dst, src), ctx); 635 } 636 637 static inline void emit_a32_sub_r(const u8 dst, const u8 src, 638 const bool is64, const bool hi, 639 struct jit_ctx *ctx) { 640 /* 64 bit : 641 * subs dst_lo, dst_lo, src_lo 642 * sbc dst_hi, dst_hi, src_hi 643 * 32 bit : 644 * sub dst_lo, dst_lo, src_lo 645 */ 646 if (!hi && is64) 647 emit(ARM_SUBS_R(dst, dst, src), ctx); 648 else if (hi && is64) 649 emit(ARM_SBC_R(dst, dst, src), ctx); 650 else 651 emit(ARM_SUB_R(dst, dst, src), ctx); 652 } 653 654 static inline void emit_alu_r(const u8 dst, const u8 src, const bool is64, 655 const bool hi, const u8 op, struct jit_ctx *ctx){ 656 switch (BPF_OP(op)) { 657 /* dst = dst + src */ 658 case BPF_ADD: 659 emit_a32_add_r(dst, src, is64, hi, ctx); 660 break; 661 /* dst = dst - src */ 662 case BPF_SUB: 663 emit_a32_sub_r(dst, src, is64, hi, ctx); 664 break; 665 /* dst = dst | src */ 666 case BPF_OR: 667 emit(ARM_ORR_R(dst, dst, src), ctx); 668 break; 669 /* dst = dst & src */ 670 case BPF_AND: 671 emit(ARM_AND_R(dst, dst, src), ctx); 672 break; 673 /* dst = dst ^ src */ 674 case BPF_XOR: 675 emit(ARM_EOR_R(dst, dst, src), ctx); 676 break; 677 /* dst = dst * src */ 678 case BPF_MUL: 679 emit(ARM_MUL(dst, dst, src), ctx); 680 break; 681 /* dst = dst << src */ 682 case BPF_LSH: 683 emit(ARM_LSL_R(dst, dst, src), ctx); 684 break; 685 /* dst = dst >> src */ 686 case BPF_RSH: 687 emit(ARM_LSR_R(dst, dst, src), ctx); 688 break; 689 /* dst = dst >> src (signed)*/ 690 case BPF_ARSH: 691 emit(ARM_MOV_SR(dst, dst, SRTYPE_ASR, src), ctx); 692 break; 693 } 694 } 695 696 /* ALU operation (32 bit) 697 * dst = dst (op) src 698 */ 699 static inline void emit_a32_alu_r(const s8 dst, const s8 src, 700 struct jit_ctx *ctx, const bool is64, 701 const bool hi, const u8 op) { 702 const s8 *tmp = bpf2a32[TMP_REG_1]; 703 s8 rn, rd; 704 705 rn = arm_bpf_get_reg32(src, tmp[1], ctx); 706 rd = arm_bpf_get_reg32(dst, tmp[0], ctx); 707 /* ALU operation */ 708 emit_alu_r(rd, rn, is64, hi, op, ctx); 709 arm_bpf_put_reg32(dst, rd, ctx); 710 } 711 712 /* ALU operation (64 bit) */ 713 static inline void emit_a32_alu_r64(const bool is64, const s8 dst[], 714 const s8 src[], struct jit_ctx *ctx, 715 const u8 op) { 716 const s8 *tmp = bpf2a32[TMP_REG_1]; 717 const s8 *tmp2 = bpf2a32[TMP_REG_2]; 718 const s8 *rd; 719 720 rd = arm_bpf_get_reg64(dst, tmp, ctx); 721 if (is64) { 722 const s8 *rs; 723 724 rs = arm_bpf_get_reg64(src, tmp2, ctx); 725 726 /* ALU operation */ 727 emit_alu_r(rd[1], rs[1], true, false, op, ctx); 728 emit_alu_r(rd[0], rs[0], true, true, op, ctx); 729 } else { 730 s8 rs; 731 732 rs = arm_bpf_get_reg32(src_lo, tmp2[1], ctx); 733 734 /* ALU operation */ 735 emit_alu_r(rd[1], rs, true, false, op, ctx); 736 if (!ctx->prog->aux->verifier_zext) 737 emit_a32_mov_i(rd[0], 0, ctx); 738 } 739 740 arm_bpf_put_reg64(dst, rd, ctx); 741 } 742 743 /* dst = src (4 bytes)*/ 744 static inline void emit_a32_mov_r(const s8 dst, const s8 src, 745 struct jit_ctx *ctx) { 746 const s8 *tmp = bpf2a32[TMP_REG_1]; 747 s8 rt; 748 749 rt = arm_bpf_get_reg32(src, tmp[0], ctx); 750 arm_bpf_put_reg32(dst, rt, ctx); 751 } 752 753 /* dst = src */ 754 static inline void emit_a32_mov_r64(const bool is64, const s8 dst[], 755 const s8 src[], 756 struct jit_ctx *ctx) { 757 if (!is64) { 758 emit_a32_mov_r(dst_lo, src_lo, ctx); 759 if (!ctx->prog->aux->verifier_zext) 760 /* Zero out high 4 bytes */ 761 emit_a32_mov_i(dst_hi, 0, ctx); 762 } else if (__LINUX_ARM_ARCH__ < 6 && 763 ctx->cpu_architecture < CPU_ARCH_ARMv5TE) { 764 /* complete 8 byte move */ 765 emit_a32_mov_r(dst_lo, src_lo, ctx); 766 emit_a32_mov_r(dst_hi, src_hi, ctx); 767 } else if (is_stacked(src_lo) && is_stacked(dst_lo)) { 768 const u8 *tmp = bpf2a32[TMP_REG_1]; 769 770 emit(ARM_LDRD_I(tmp[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(src_lo)), ctx); 771 emit(ARM_STRD_I(tmp[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(dst_lo)), ctx); 772 } else if (is_stacked(src_lo)) { 773 emit(ARM_LDRD_I(dst[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(src_lo)), ctx); 774 } else if (is_stacked(dst_lo)) { 775 emit(ARM_STRD_I(src[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(dst_lo)), ctx); 776 } else { 777 emit(ARM_MOV_R(dst[0], src[0]), ctx); 778 emit(ARM_MOV_R(dst[1], src[1]), ctx); 779 } 780 } 781 782 /* Shift operations */ 783 static inline void emit_a32_alu_i(const s8 dst, const u32 val, 784 struct jit_ctx *ctx, const u8 op) { 785 const s8 *tmp = bpf2a32[TMP_REG_1]; 786 s8 rd; 787 788 rd = arm_bpf_get_reg32(dst, tmp[0], ctx); 789 790 /* Do shift operation */ 791 switch (op) { 792 case BPF_LSH: 793 emit(ARM_LSL_I(rd, rd, val), ctx); 794 break; 795 case BPF_RSH: 796 emit(ARM_LSR_I(rd, rd, val), ctx); 797 break; 798 case BPF_ARSH: 799 emit(ARM_ASR_I(rd, rd, val), ctx); 800 break; 801 case BPF_NEG: 802 emit(ARM_RSB_I(rd, rd, val), ctx); 803 break; 804 } 805 806 arm_bpf_put_reg32(dst, rd, ctx); 807 } 808 809 /* dst = ~dst (64 bit) */ 810 static inline void emit_a32_neg64(const s8 dst[], 811 struct jit_ctx *ctx){ 812 const s8 *tmp = bpf2a32[TMP_REG_1]; 813 const s8 *rd; 814 815 /* Setup Operand */ 816 rd = arm_bpf_get_reg64(dst, tmp, ctx); 817 818 /* Do Negate Operation */ 819 emit(ARM_RSBS_I(rd[1], rd[1], 0), ctx); 820 emit(ARM_RSC_I(rd[0], rd[0], 0), ctx); 821 822 arm_bpf_put_reg64(dst, rd, ctx); 823 } 824 825 /* dst = dst << src */ 826 static inline void emit_a32_lsh_r64(const s8 dst[], const s8 src[], 827 struct jit_ctx *ctx) { 828 const s8 *tmp = bpf2a32[TMP_REG_1]; 829 const s8 *tmp2 = bpf2a32[TMP_REG_2]; 830 const s8 *rd; 831 s8 rt; 832 833 /* Setup Operands */ 834 rt = arm_bpf_get_reg32(src_lo, tmp2[1], ctx); 835 rd = arm_bpf_get_reg64(dst, tmp, ctx); 836 837 /* Do LSH operation */ 838 emit(ARM_SUB_I(ARM_IP, rt, 32), ctx); 839 emit(ARM_RSB_I(tmp2[0], rt, 32), ctx); 840 emit(ARM_MOV_SR(ARM_LR, rd[0], SRTYPE_ASL, rt), ctx); 841 emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[1], SRTYPE_ASL, ARM_IP), ctx); 842 emit(ARM_ORR_SR(ARM_IP, ARM_LR, rd[1], SRTYPE_LSR, tmp2[0]), ctx); 843 emit(ARM_MOV_SR(ARM_LR, rd[1], SRTYPE_ASL, rt), ctx); 844 845 arm_bpf_put_reg32(dst_lo, ARM_LR, ctx); 846 arm_bpf_put_reg32(dst_hi, ARM_IP, ctx); 847 } 848 849 /* dst = dst >> src (signed)*/ 850 static inline void emit_a32_arsh_r64(const s8 dst[], const s8 src[], 851 struct jit_ctx *ctx) { 852 const s8 *tmp = bpf2a32[TMP_REG_1]; 853 const s8 *tmp2 = bpf2a32[TMP_REG_2]; 854 const s8 *rd; 855 s8 rt; 856 857 /* Setup Operands */ 858 rt = arm_bpf_get_reg32(src_lo, tmp2[1], ctx); 859 rd = arm_bpf_get_reg64(dst, tmp, ctx); 860 861 /* Do the ARSH operation */ 862 emit(ARM_RSB_I(ARM_IP, rt, 32), ctx); 863 emit(ARM_SUBS_I(tmp2[0], rt, 32), ctx); 864 emit(ARM_MOV_SR(ARM_LR, rd[1], SRTYPE_LSR, rt), ctx); 865 emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASL, ARM_IP), ctx); 866 _emit(ARM_COND_PL, 867 ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASR, tmp2[0]), ctx); 868 emit(ARM_MOV_SR(ARM_IP, rd[0], SRTYPE_ASR, rt), ctx); 869 870 arm_bpf_put_reg32(dst_lo, ARM_LR, ctx); 871 arm_bpf_put_reg32(dst_hi, ARM_IP, ctx); 872 } 873 874 /* dst = dst >> src */ 875 static inline void emit_a32_rsh_r64(const s8 dst[], const s8 src[], 876 struct jit_ctx *ctx) { 877 const s8 *tmp = bpf2a32[TMP_REG_1]; 878 const s8 *tmp2 = bpf2a32[TMP_REG_2]; 879 const s8 *rd; 880 s8 rt; 881 882 /* Setup Operands */ 883 rt = arm_bpf_get_reg32(src_lo, tmp2[1], ctx); 884 rd = arm_bpf_get_reg64(dst, tmp, ctx); 885 886 /* Do RSH operation */ 887 emit(ARM_RSB_I(ARM_IP, rt, 32), ctx); 888 emit(ARM_SUBS_I(tmp2[0], rt, 32), ctx); 889 emit(ARM_MOV_SR(ARM_LR, rd[1], SRTYPE_LSR, rt), ctx); 890 emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASL, ARM_IP), ctx); 891 emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_LSR, tmp2[0]), ctx); 892 emit(ARM_MOV_SR(ARM_IP, rd[0], SRTYPE_LSR, rt), ctx); 893 894 arm_bpf_put_reg32(dst_lo, ARM_LR, ctx); 895 arm_bpf_put_reg32(dst_hi, ARM_IP, ctx); 896 } 897 898 /* dst = dst << val */ 899 static inline void emit_a32_lsh_i64(const s8 dst[], 900 const u32 val, struct jit_ctx *ctx){ 901 const s8 *tmp = bpf2a32[TMP_REG_1]; 902 const s8 *tmp2 = bpf2a32[TMP_REG_2]; 903 const s8 *rd; 904 905 /* Setup operands */ 906 rd = arm_bpf_get_reg64(dst, tmp, ctx); 907 908 /* Do LSH operation */ 909 if (val < 32) { 910 emit(ARM_MOV_SI(tmp2[0], rd[0], SRTYPE_ASL, val), ctx); 911 emit(ARM_ORR_SI(rd[0], tmp2[0], rd[1], SRTYPE_LSR, 32 - val), ctx); 912 emit(ARM_MOV_SI(rd[1], rd[1], SRTYPE_ASL, val), ctx); 913 } else { 914 if (val == 32) 915 emit(ARM_MOV_R(rd[0], rd[1]), ctx); 916 else 917 emit(ARM_MOV_SI(rd[0], rd[1], SRTYPE_ASL, val - 32), ctx); 918 emit(ARM_EOR_R(rd[1], rd[1], rd[1]), ctx); 919 } 920 921 arm_bpf_put_reg64(dst, rd, ctx); 922 } 923 924 /* dst = dst >> val */ 925 static inline void emit_a32_rsh_i64(const s8 dst[], 926 const u32 val, struct jit_ctx *ctx) { 927 const s8 *tmp = bpf2a32[TMP_REG_1]; 928 const s8 *tmp2 = bpf2a32[TMP_REG_2]; 929 const s8 *rd; 930 931 /* Setup operands */ 932 rd = arm_bpf_get_reg64(dst, tmp, ctx); 933 934 /* Do LSR operation */ 935 if (val == 0) { 936 /* An immediate value of 0 encodes a shift amount of 32 937 * for LSR. To shift by 0, don't do anything. 938 */ 939 } else if (val < 32) { 940 emit(ARM_MOV_SI(tmp2[1], rd[1], SRTYPE_LSR, val), ctx); 941 emit(ARM_ORR_SI(rd[1], tmp2[1], rd[0], SRTYPE_ASL, 32 - val), ctx); 942 emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_LSR, val), ctx); 943 } else if (val == 32) { 944 emit(ARM_MOV_R(rd[1], rd[0]), ctx); 945 emit(ARM_MOV_I(rd[0], 0), ctx); 946 } else { 947 emit(ARM_MOV_SI(rd[1], rd[0], SRTYPE_LSR, val - 32), ctx); 948 emit(ARM_MOV_I(rd[0], 0), ctx); 949 } 950 951 arm_bpf_put_reg64(dst, rd, ctx); 952 } 953 954 /* dst = dst >> val (signed) */ 955 static inline void emit_a32_arsh_i64(const s8 dst[], 956 const u32 val, struct jit_ctx *ctx){ 957 const s8 *tmp = bpf2a32[TMP_REG_1]; 958 const s8 *tmp2 = bpf2a32[TMP_REG_2]; 959 const s8 *rd; 960 961 /* Setup operands */ 962 rd = arm_bpf_get_reg64(dst, tmp, ctx); 963 964 /* Do ARSH operation */ 965 if (val == 0) { 966 /* An immediate value of 0 encodes a shift amount of 32 967 * for ASR. To shift by 0, don't do anything. 968 */ 969 } else if (val < 32) { 970 emit(ARM_MOV_SI(tmp2[1], rd[1], SRTYPE_LSR, val), ctx); 971 emit(ARM_ORR_SI(rd[1], tmp2[1], rd[0], SRTYPE_ASL, 32 - val), ctx); 972 emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_ASR, val), ctx); 973 } else if (val == 32) { 974 emit(ARM_MOV_R(rd[1], rd[0]), ctx); 975 emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_ASR, 31), ctx); 976 } else { 977 emit(ARM_MOV_SI(rd[1], rd[0], SRTYPE_ASR, val - 32), ctx); 978 emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_ASR, 31), ctx); 979 } 980 981 arm_bpf_put_reg64(dst, rd, ctx); 982 } 983 984 static inline void emit_a32_mul_r64(const s8 dst[], const s8 src[], 985 struct jit_ctx *ctx) { 986 const s8 *tmp = bpf2a32[TMP_REG_1]; 987 const s8 *tmp2 = bpf2a32[TMP_REG_2]; 988 const s8 *rd, *rt; 989 990 /* Setup operands for multiplication */ 991 rd = arm_bpf_get_reg64(dst, tmp, ctx); 992 rt = arm_bpf_get_reg64(src, tmp2, ctx); 993 994 /* Do Multiplication */ 995 emit(ARM_MUL(ARM_IP, rd[1], rt[0]), ctx); 996 emit(ARM_MUL(ARM_LR, rd[0], rt[1]), ctx); 997 emit(ARM_ADD_R(ARM_LR, ARM_IP, ARM_LR), ctx); 998 999 emit(ARM_UMULL(ARM_IP, rd[0], rd[1], rt[1]), ctx); 1000 emit(ARM_ADD_R(rd[0], ARM_LR, rd[0]), ctx); 1001 1002 arm_bpf_put_reg32(dst_lo, ARM_IP, ctx); 1003 arm_bpf_put_reg32(dst_hi, rd[0], ctx); 1004 } 1005 1006 static bool is_ldst_imm(s16 off, const u8 size) 1007 { 1008 s16 off_max = 0; 1009 1010 switch (size) { 1011 case BPF_B: 1012 case BPF_W: 1013 off_max = 0xfff; 1014 break; 1015 case BPF_H: 1016 off_max = 0xff; 1017 break; 1018 case BPF_DW: 1019 /* Need to make sure off+4 does not overflow. */ 1020 off_max = 0xfff - 4; 1021 break; 1022 } 1023 return -off_max <= off && off <= off_max; 1024 } 1025 1026 /* *(size *)(dst + off) = src */ 1027 static inline void emit_str_r(const s8 dst, const s8 src[], 1028 s16 off, struct jit_ctx *ctx, const u8 sz){ 1029 const s8 *tmp = bpf2a32[TMP_REG_1]; 1030 s8 rd; 1031 1032 rd = arm_bpf_get_reg32(dst, tmp[1], ctx); 1033 1034 if (!is_ldst_imm(off, sz)) { 1035 emit_a32_mov_i(tmp[0], off, ctx); 1036 emit(ARM_ADD_R(tmp[0], tmp[0], rd), ctx); 1037 rd = tmp[0]; 1038 off = 0; 1039 } 1040 switch (sz) { 1041 case BPF_B: 1042 /* Store a Byte */ 1043 emit(ARM_STRB_I(src_lo, rd, off), ctx); 1044 break; 1045 case BPF_H: 1046 /* Store a HalfWord */ 1047 emit(ARM_STRH_I(src_lo, rd, off), ctx); 1048 break; 1049 case BPF_W: 1050 /* Store a Word */ 1051 emit(ARM_STR_I(src_lo, rd, off), ctx); 1052 break; 1053 case BPF_DW: 1054 /* Store a Double Word */ 1055 emit(ARM_STR_I(src_lo, rd, off), ctx); 1056 emit(ARM_STR_I(src_hi, rd, off + 4), ctx); 1057 break; 1058 } 1059 } 1060 1061 /* dst = *(size*)(src + off) */ 1062 static inline void emit_ldx_r(const s8 dst[], const s8 src, 1063 s16 off, struct jit_ctx *ctx, const u8 sz){ 1064 const s8 *tmp = bpf2a32[TMP_REG_1]; 1065 const s8 *rd = is_stacked(dst_lo) ? tmp : dst; 1066 s8 rm = src; 1067 1068 if (!is_ldst_imm(off, sz)) { 1069 emit_a32_mov_i(tmp[0], off, ctx); 1070 emit(ARM_ADD_R(tmp[0], tmp[0], src), ctx); 1071 rm = tmp[0]; 1072 off = 0; 1073 } else if (rd[1] == rm) { 1074 emit(ARM_MOV_R(tmp[0], rm), ctx); 1075 rm = tmp[0]; 1076 } 1077 switch (sz) { 1078 case BPF_B: 1079 /* Load a Byte */ 1080 emit(ARM_LDRB_I(rd[1], rm, off), ctx); 1081 if (!ctx->prog->aux->verifier_zext) 1082 emit_a32_mov_i(rd[0], 0, ctx); 1083 break; 1084 case BPF_H: 1085 /* Load a HalfWord */ 1086 emit(ARM_LDRH_I(rd[1], rm, off), ctx); 1087 if (!ctx->prog->aux->verifier_zext) 1088 emit_a32_mov_i(rd[0], 0, ctx); 1089 break; 1090 case BPF_W: 1091 /* Load a Word */ 1092 emit(ARM_LDR_I(rd[1], rm, off), ctx); 1093 if (!ctx->prog->aux->verifier_zext) 1094 emit_a32_mov_i(rd[0], 0, ctx); 1095 break; 1096 case BPF_DW: 1097 /* Load a Double Word */ 1098 emit(ARM_LDR_I(rd[1], rm, off), ctx); 1099 emit(ARM_LDR_I(rd[0], rm, off + 4), ctx); 1100 break; 1101 } 1102 arm_bpf_put_reg64(dst, rd, ctx); 1103 } 1104 1105 /* Arithmatic Operation */ 1106 static inline void emit_ar_r(const u8 rd, const u8 rt, const u8 rm, 1107 const u8 rn, struct jit_ctx *ctx, u8 op, 1108 bool is_jmp64) { 1109 switch (op) { 1110 case BPF_JSET: 1111 if (is_jmp64) { 1112 emit(ARM_AND_R(ARM_IP, rt, rn), ctx); 1113 emit(ARM_AND_R(ARM_LR, rd, rm), ctx); 1114 emit(ARM_ORRS_R(ARM_IP, ARM_LR, ARM_IP), ctx); 1115 } else { 1116 emit(ARM_ANDS_R(ARM_IP, rt, rn), ctx); 1117 } 1118 break; 1119 case BPF_JEQ: 1120 case BPF_JNE: 1121 case BPF_JGT: 1122 case BPF_JGE: 1123 case BPF_JLE: 1124 case BPF_JLT: 1125 if (is_jmp64) { 1126 emit(ARM_CMP_R(rd, rm), ctx); 1127 /* Only compare low halve if high halve are equal. */ 1128 _emit(ARM_COND_EQ, ARM_CMP_R(rt, rn), ctx); 1129 } else { 1130 emit(ARM_CMP_R(rt, rn), ctx); 1131 } 1132 break; 1133 case BPF_JSLE: 1134 case BPF_JSGT: 1135 emit(ARM_CMP_R(rn, rt), ctx); 1136 if (is_jmp64) 1137 emit(ARM_SBCS_R(ARM_IP, rm, rd), ctx); 1138 break; 1139 case BPF_JSLT: 1140 case BPF_JSGE: 1141 emit(ARM_CMP_R(rt, rn), ctx); 1142 if (is_jmp64) 1143 emit(ARM_SBCS_R(ARM_IP, rd, rm), ctx); 1144 break; 1145 } 1146 } 1147 1148 static int out_offset = -1; /* initialized on the first pass of build_body() */ 1149 static int emit_bpf_tail_call(struct jit_ctx *ctx) 1150 { 1151 1152 /* bpf_tail_call(void *prog_ctx, struct bpf_array *array, u64 index) */ 1153 const s8 *r2 = bpf2a32[BPF_REG_2]; 1154 const s8 *r3 = bpf2a32[BPF_REG_3]; 1155 const s8 *tmp = bpf2a32[TMP_REG_1]; 1156 const s8 *tmp2 = bpf2a32[TMP_REG_2]; 1157 const s8 *tcc = bpf2a32[TCALL_CNT]; 1158 const s8 *tc; 1159 const int idx0 = ctx->idx; 1160 #define cur_offset (ctx->idx - idx0) 1161 #define jmp_offset (out_offset - (cur_offset) - 2) 1162 u32 lo, hi; 1163 s8 r_array, r_index; 1164 int off; 1165 1166 /* if (index >= array->map.max_entries) 1167 * goto out; 1168 */ 1169 BUILD_BUG_ON(offsetof(struct bpf_array, map.max_entries) > 1170 ARM_INST_LDST__IMM12); 1171 off = offsetof(struct bpf_array, map.max_entries); 1172 r_array = arm_bpf_get_reg32(r2[1], tmp2[0], ctx); 1173 /* index is 32-bit for arrays */ 1174 r_index = arm_bpf_get_reg32(r3[1], tmp2[1], ctx); 1175 /* array->map.max_entries */ 1176 emit(ARM_LDR_I(tmp[1], r_array, off), ctx); 1177 /* index >= array->map.max_entries */ 1178 emit(ARM_CMP_R(r_index, tmp[1]), ctx); 1179 _emit(ARM_COND_CS, ARM_B(jmp_offset), ctx); 1180 1181 /* tmp2[0] = array, tmp2[1] = index */ 1182 1183 /* if (tail_call_cnt > MAX_TAIL_CALL_CNT) 1184 * goto out; 1185 * tail_call_cnt++; 1186 */ 1187 lo = (u32)MAX_TAIL_CALL_CNT; 1188 hi = (u32)((u64)MAX_TAIL_CALL_CNT >> 32); 1189 tc = arm_bpf_get_reg64(tcc, tmp, ctx); 1190 emit(ARM_CMP_I(tc[0], hi), ctx); 1191 _emit(ARM_COND_EQ, ARM_CMP_I(tc[1], lo), ctx); 1192 _emit(ARM_COND_HI, ARM_B(jmp_offset), ctx); 1193 emit(ARM_ADDS_I(tc[1], tc[1], 1), ctx); 1194 emit(ARM_ADC_I(tc[0], tc[0], 0), ctx); 1195 arm_bpf_put_reg64(tcc, tmp, ctx); 1196 1197 /* prog = array->ptrs[index] 1198 * if (prog == NULL) 1199 * goto out; 1200 */ 1201 BUILD_BUG_ON(imm8m(offsetof(struct bpf_array, ptrs)) < 0); 1202 off = imm8m(offsetof(struct bpf_array, ptrs)); 1203 emit(ARM_ADD_I(tmp[1], r_array, off), ctx); 1204 emit(ARM_LDR_R_SI(tmp[1], tmp[1], r_index, SRTYPE_ASL, 2), ctx); 1205 emit(ARM_CMP_I(tmp[1], 0), ctx); 1206 _emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx); 1207 1208 /* goto *(prog->bpf_func + prologue_size); */ 1209 BUILD_BUG_ON(offsetof(struct bpf_prog, bpf_func) > 1210 ARM_INST_LDST__IMM12); 1211 off = offsetof(struct bpf_prog, bpf_func); 1212 emit(ARM_LDR_I(tmp[1], tmp[1], off), ctx); 1213 emit(ARM_ADD_I(tmp[1], tmp[1], ctx->prologue_bytes), ctx); 1214 emit_bx_r(tmp[1], ctx); 1215 1216 /* out: */ 1217 if (out_offset == -1) 1218 out_offset = cur_offset; 1219 if (cur_offset != out_offset) { 1220 pr_err_once("tail_call out_offset = %d, expected %d!\n", 1221 cur_offset, out_offset); 1222 return -1; 1223 } 1224 return 0; 1225 #undef cur_offset 1226 #undef jmp_offset 1227 } 1228 1229 /* 0xabcd => 0xcdab */ 1230 static inline void emit_rev16(const u8 rd, const u8 rn, struct jit_ctx *ctx) 1231 { 1232 #if __LINUX_ARM_ARCH__ < 6 1233 const s8 *tmp2 = bpf2a32[TMP_REG_2]; 1234 1235 emit(ARM_AND_I(tmp2[1], rn, 0xff), ctx); 1236 emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 8), ctx); 1237 emit(ARM_AND_I(tmp2[0], tmp2[0], 0xff), ctx); 1238 emit(ARM_ORR_SI(rd, tmp2[0], tmp2[1], SRTYPE_LSL, 8), ctx); 1239 #else /* ARMv6+ */ 1240 emit(ARM_REV16(rd, rn), ctx); 1241 #endif 1242 } 1243 1244 /* 0xabcdefgh => 0xghefcdab */ 1245 static inline void emit_rev32(const u8 rd, const u8 rn, struct jit_ctx *ctx) 1246 { 1247 #if __LINUX_ARM_ARCH__ < 6 1248 const s8 *tmp2 = bpf2a32[TMP_REG_2]; 1249 1250 emit(ARM_AND_I(tmp2[1], rn, 0xff), ctx); 1251 emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 24), ctx); 1252 emit(ARM_ORR_SI(ARM_IP, tmp2[0], tmp2[1], SRTYPE_LSL, 24), ctx); 1253 1254 emit(ARM_MOV_SI(tmp2[1], rn, SRTYPE_LSR, 8), ctx); 1255 emit(ARM_AND_I(tmp2[1], tmp2[1], 0xff), ctx); 1256 emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 16), ctx); 1257 emit(ARM_AND_I(tmp2[0], tmp2[0], 0xff), ctx); 1258 emit(ARM_MOV_SI(tmp2[0], tmp2[0], SRTYPE_LSL, 8), ctx); 1259 emit(ARM_ORR_SI(tmp2[0], tmp2[0], tmp2[1], SRTYPE_LSL, 16), ctx); 1260 emit(ARM_ORR_R(rd, ARM_IP, tmp2[0]), ctx); 1261 1262 #else /* ARMv6+ */ 1263 emit(ARM_REV(rd, rn), ctx); 1264 #endif 1265 } 1266 1267 // push the scratch stack register on top of the stack 1268 static inline void emit_push_r64(const s8 src[], struct jit_ctx *ctx) 1269 { 1270 const s8 *tmp2 = bpf2a32[TMP_REG_2]; 1271 const s8 *rt; 1272 u16 reg_set = 0; 1273 1274 rt = arm_bpf_get_reg64(src, tmp2, ctx); 1275 1276 reg_set = (1 << rt[1]) | (1 << rt[0]); 1277 emit(ARM_PUSH(reg_set), ctx); 1278 } 1279 1280 static void build_prologue(struct jit_ctx *ctx) 1281 { 1282 const s8 arm_r0 = bpf2a32[BPF_REG_0][1]; 1283 const s8 *bpf_r1 = bpf2a32[BPF_REG_1]; 1284 const s8 *bpf_fp = bpf2a32[BPF_REG_FP]; 1285 const s8 *tcc = bpf2a32[TCALL_CNT]; 1286 1287 /* Save callee saved registers. */ 1288 #ifdef CONFIG_FRAME_POINTER 1289 u16 reg_set = CALLEE_PUSH_MASK | 1 << ARM_IP | 1 << ARM_PC; 1290 emit(ARM_MOV_R(ARM_IP, ARM_SP), ctx); 1291 emit(ARM_PUSH(reg_set), ctx); 1292 emit(ARM_SUB_I(ARM_FP, ARM_IP, 4), ctx); 1293 #else 1294 emit(ARM_PUSH(CALLEE_PUSH_MASK), ctx); 1295 emit(ARM_MOV_R(ARM_FP, ARM_SP), ctx); 1296 #endif 1297 /* mov r3, #0 */ 1298 /* sub r2, sp, #SCRATCH_SIZE */ 1299 emit(ARM_MOV_I(bpf_r1[0], 0), ctx); 1300 emit(ARM_SUB_I(bpf_r1[1], ARM_SP, SCRATCH_SIZE), ctx); 1301 1302 ctx->stack_size = imm8m(STACK_SIZE); 1303 1304 /* Set up function call stack */ 1305 emit(ARM_SUB_I(ARM_SP, ARM_SP, ctx->stack_size), ctx); 1306 1307 /* Set up BPF prog stack base register */ 1308 emit_a32_mov_r64(true, bpf_fp, bpf_r1, ctx); 1309 1310 /* Initialize Tail Count */ 1311 emit(ARM_MOV_I(bpf_r1[1], 0), ctx); 1312 emit_a32_mov_r64(true, tcc, bpf_r1, ctx); 1313 1314 /* Move BPF_CTX to BPF_R1 */ 1315 emit(ARM_MOV_R(bpf_r1[1], arm_r0), ctx); 1316 1317 /* end of prologue */ 1318 } 1319 1320 /* restore callee saved registers. */ 1321 static void build_epilogue(struct jit_ctx *ctx) 1322 { 1323 #ifdef CONFIG_FRAME_POINTER 1324 /* When using frame pointers, some additional registers need to 1325 * be loaded. */ 1326 u16 reg_set = CALLEE_POP_MASK | 1 << ARM_SP; 1327 emit(ARM_SUB_I(ARM_SP, ARM_FP, hweight16(reg_set) * 4), ctx); 1328 emit(ARM_LDM(ARM_SP, reg_set), ctx); 1329 #else 1330 /* Restore callee saved registers. */ 1331 emit(ARM_MOV_R(ARM_SP, ARM_FP), ctx); 1332 emit(ARM_POP(CALLEE_POP_MASK), ctx); 1333 #endif 1334 } 1335 1336 /* 1337 * Convert an eBPF instruction to native instruction, i.e 1338 * JITs an eBPF instruction. 1339 * Returns : 1340 * 0 - Successfully JITed an 8-byte eBPF instruction 1341 * >0 - Successfully JITed a 16-byte eBPF instruction 1342 * <0 - Failed to JIT. 1343 */ 1344 static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) 1345 { 1346 const u8 code = insn->code; 1347 const s8 *dst = bpf2a32[insn->dst_reg]; 1348 const s8 *src = bpf2a32[insn->src_reg]; 1349 const s8 *tmp = bpf2a32[TMP_REG_1]; 1350 const s8 *tmp2 = bpf2a32[TMP_REG_2]; 1351 const s16 off = insn->off; 1352 const s32 imm = insn->imm; 1353 const int i = insn - ctx->prog->insnsi; 1354 const bool is64 = BPF_CLASS(code) == BPF_ALU64; 1355 const s8 *rd, *rs; 1356 s8 rd_lo, rt, rm, rn; 1357 s32 jmp_offset; 1358 1359 #define check_imm(bits, imm) do { \ 1360 if ((imm) >= (1 << ((bits) - 1)) || \ 1361 (imm) < -(1 << ((bits) - 1))) { \ 1362 pr_info("[%2d] imm=%d(0x%x) out of range\n", \ 1363 i, imm, imm); \ 1364 return -EINVAL; \ 1365 } \ 1366 } while (0) 1367 #define check_imm24(imm) check_imm(24, imm) 1368 1369 switch (code) { 1370 /* ALU operations */ 1371 1372 /* dst = src */ 1373 case BPF_ALU | BPF_MOV | BPF_K: 1374 case BPF_ALU | BPF_MOV | BPF_X: 1375 case BPF_ALU64 | BPF_MOV | BPF_K: 1376 case BPF_ALU64 | BPF_MOV | BPF_X: 1377 switch (BPF_SRC(code)) { 1378 case BPF_X: 1379 if (imm == 1) { 1380 /* Special mov32 for zext */ 1381 emit_a32_mov_i(dst_hi, 0, ctx); 1382 break; 1383 } 1384 emit_a32_mov_r64(is64, dst, src, ctx); 1385 break; 1386 case BPF_K: 1387 /* Sign-extend immediate value to destination reg */ 1388 emit_a32_mov_se_i64(is64, dst, imm, ctx); 1389 break; 1390 } 1391 break; 1392 /* dst = dst + src/imm */ 1393 /* dst = dst - src/imm */ 1394 /* dst = dst | src/imm */ 1395 /* dst = dst & src/imm */ 1396 /* dst = dst ^ src/imm */ 1397 /* dst = dst * src/imm */ 1398 /* dst = dst << src */ 1399 /* dst = dst >> src */ 1400 case BPF_ALU | BPF_ADD | BPF_K: 1401 case BPF_ALU | BPF_ADD | BPF_X: 1402 case BPF_ALU | BPF_SUB | BPF_K: 1403 case BPF_ALU | BPF_SUB | BPF_X: 1404 case BPF_ALU | BPF_OR | BPF_K: 1405 case BPF_ALU | BPF_OR | BPF_X: 1406 case BPF_ALU | BPF_AND | BPF_K: 1407 case BPF_ALU | BPF_AND | BPF_X: 1408 case BPF_ALU | BPF_XOR | BPF_K: 1409 case BPF_ALU | BPF_XOR | BPF_X: 1410 case BPF_ALU | BPF_MUL | BPF_K: 1411 case BPF_ALU | BPF_MUL | BPF_X: 1412 case BPF_ALU | BPF_LSH | BPF_X: 1413 case BPF_ALU | BPF_RSH | BPF_X: 1414 case BPF_ALU | BPF_ARSH | BPF_X: 1415 case BPF_ALU64 | BPF_ADD | BPF_K: 1416 case BPF_ALU64 | BPF_ADD | BPF_X: 1417 case BPF_ALU64 | BPF_SUB | BPF_K: 1418 case BPF_ALU64 | BPF_SUB | BPF_X: 1419 case BPF_ALU64 | BPF_OR | BPF_K: 1420 case BPF_ALU64 | BPF_OR | BPF_X: 1421 case BPF_ALU64 | BPF_AND | BPF_K: 1422 case BPF_ALU64 | BPF_AND | BPF_X: 1423 case BPF_ALU64 | BPF_XOR | BPF_K: 1424 case BPF_ALU64 | BPF_XOR | BPF_X: 1425 switch (BPF_SRC(code)) { 1426 case BPF_X: 1427 emit_a32_alu_r64(is64, dst, src, ctx, BPF_OP(code)); 1428 break; 1429 case BPF_K: 1430 /* Move immediate value to the temporary register 1431 * and then do the ALU operation on the temporary 1432 * register as this will sign-extend the immediate 1433 * value into temporary reg and then it would be 1434 * safe to do the operation on it. 1435 */ 1436 emit_a32_mov_se_i64(is64, tmp2, imm, ctx); 1437 emit_a32_alu_r64(is64, dst, tmp2, ctx, BPF_OP(code)); 1438 break; 1439 } 1440 break; 1441 /* dst = dst / src(imm) */ 1442 /* dst = dst % src(imm) */ 1443 case BPF_ALU | BPF_DIV | BPF_K: 1444 case BPF_ALU | BPF_DIV | BPF_X: 1445 case BPF_ALU | BPF_MOD | BPF_K: 1446 case BPF_ALU | BPF_MOD | BPF_X: 1447 rd_lo = arm_bpf_get_reg32(dst_lo, tmp2[1], ctx); 1448 switch (BPF_SRC(code)) { 1449 case BPF_X: 1450 rt = arm_bpf_get_reg32(src_lo, tmp2[0], ctx); 1451 break; 1452 case BPF_K: 1453 rt = tmp2[0]; 1454 emit_a32_mov_i(rt, imm, ctx); 1455 break; 1456 default: 1457 rt = src_lo; 1458 break; 1459 } 1460 emit_udivmod(rd_lo, rd_lo, rt, ctx, BPF_OP(code)); 1461 arm_bpf_put_reg32(dst_lo, rd_lo, ctx); 1462 if (!ctx->prog->aux->verifier_zext) 1463 emit_a32_mov_i(dst_hi, 0, ctx); 1464 break; 1465 case BPF_ALU64 | BPF_DIV | BPF_K: 1466 case BPF_ALU64 | BPF_DIV | BPF_X: 1467 case BPF_ALU64 | BPF_MOD | BPF_K: 1468 case BPF_ALU64 | BPF_MOD | BPF_X: 1469 goto notyet; 1470 /* dst = dst << imm */ 1471 /* dst = dst >> imm */ 1472 /* dst = dst >> imm (signed) */ 1473 case BPF_ALU | BPF_LSH | BPF_K: 1474 case BPF_ALU | BPF_RSH | BPF_K: 1475 case BPF_ALU | BPF_ARSH | BPF_K: 1476 if (unlikely(imm > 31)) 1477 return -EINVAL; 1478 if (imm) 1479 emit_a32_alu_i(dst_lo, imm, ctx, BPF_OP(code)); 1480 if (!ctx->prog->aux->verifier_zext) 1481 emit_a32_mov_i(dst_hi, 0, ctx); 1482 break; 1483 /* dst = dst << imm */ 1484 case BPF_ALU64 | BPF_LSH | BPF_K: 1485 if (unlikely(imm > 63)) 1486 return -EINVAL; 1487 emit_a32_lsh_i64(dst, imm, ctx); 1488 break; 1489 /* dst = dst >> imm */ 1490 case BPF_ALU64 | BPF_RSH | BPF_K: 1491 if (unlikely(imm > 63)) 1492 return -EINVAL; 1493 emit_a32_rsh_i64(dst, imm, ctx); 1494 break; 1495 /* dst = dst << src */ 1496 case BPF_ALU64 | BPF_LSH | BPF_X: 1497 emit_a32_lsh_r64(dst, src, ctx); 1498 break; 1499 /* dst = dst >> src */ 1500 case BPF_ALU64 | BPF_RSH | BPF_X: 1501 emit_a32_rsh_r64(dst, src, ctx); 1502 break; 1503 /* dst = dst >> src (signed) */ 1504 case BPF_ALU64 | BPF_ARSH | BPF_X: 1505 emit_a32_arsh_r64(dst, src, ctx); 1506 break; 1507 /* dst = dst >> imm (signed) */ 1508 case BPF_ALU64 | BPF_ARSH | BPF_K: 1509 if (unlikely(imm > 63)) 1510 return -EINVAL; 1511 emit_a32_arsh_i64(dst, imm, ctx); 1512 break; 1513 /* dst = ~dst */ 1514 case BPF_ALU | BPF_NEG: 1515 emit_a32_alu_i(dst_lo, 0, ctx, BPF_OP(code)); 1516 if (!ctx->prog->aux->verifier_zext) 1517 emit_a32_mov_i(dst_hi, 0, ctx); 1518 break; 1519 /* dst = ~dst (64 bit) */ 1520 case BPF_ALU64 | BPF_NEG: 1521 emit_a32_neg64(dst, ctx); 1522 break; 1523 /* dst = dst * src/imm */ 1524 case BPF_ALU64 | BPF_MUL | BPF_X: 1525 case BPF_ALU64 | BPF_MUL | BPF_K: 1526 switch (BPF_SRC(code)) { 1527 case BPF_X: 1528 emit_a32_mul_r64(dst, src, ctx); 1529 break; 1530 case BPF_K: 1531 /* Move immediate value to the temporary register 1532 * and then do the multiplication on it as this 1533 * will sign-extend the immediate value into temp 1534 * reg then it would be safe to do the operation 1535 * on it. 1536 */ 1537 emit_a32_mov_se_i64(is64, tmp2, imm, ctx); 1538 emit_a32_mul_r64(dst, tmp2, ctx); 1539 break; 1540 } 1541 break; 1542 /* dst = htole(dst) */ 1543 /* dst = htobe(dst) */ 1544 case BPF_ALU | BPF_END | BPF_FROM_LE: 1545 case BPF_ALU | BPF_END | BPF_FROM_BE: 1546 rd = arm_bpf_get_reg64(dst, tmp, ctx); 1547 if (BPF_SRC(code) == BPF_FROM_LE) 1548 goto emit_bswap_uxt; 1549 switch (imm) { 1550 case 16: 1551 emit_rev16(rd[1], rd[1], ctx); 1552 goto emit_bswap_uxt; 1553 case 32: 1554 emit_rev32(rd[1], rd[1], ctx); 1555 goto emit_bswap_uxt; 1556 case 64: 1557 emit_rev32(ARM_LR, rd[1], ctx); 1558 emit_rev32(rd[1], rd[0], ctx); 1559 emit(ARM_MOV_R(rd[0], ARM_LR), ctx); 1560 break; 1561 } 1562 goto exit; 1563 emit_bswap_uxt: 1564 switch (imm) { 1565 case 16: 1566 /* zero-extend 16 bits into 64 bits */ 1567 #if __LINUX_ARM_ARCH__ < 6 1568 emit_a32_mov_i(tmp2[1], 0xffff, ctx); 1569 emit(ARM_AND_R(rd[1], rd[1], tmp2[1]), ctx); 1570 #else /* ARMv6+ */ 1571 emit(ARM_UXTH(rd[1], rd[1]), ctx); 1572 #endif 1573 if (!ctx->prog->aux->verifier_zext) 1574 emit(ARM_EOR_R(rd[0], rd[0], rd[0]), ctx); 1575 break; 1576 case 32: 1577 /* zero-extend 32 bits into 64 bits */ 1578 if (!ctx->prog->aux->verifier_zext) 1579 emit(ARM_EOR_R(rd[0], rd[0], rd[0]), ctx); 1580 break; 1581 case 64: 1582 /* nop */ 1583 break; 1584 } 1585 exit: 1586 arm_bpf_put_reg64(dst, rd, ctx); 1587 break; 1588 /* dst = imm64 */ 1589 case BPF_LD | BPF_IMM | BPF_DW: 1590 { 1591 u64 val = (u32)imm | (u64)insn[1].imm << 32; 1592 1593 emit_a32_mov_i64(dst, val, ctx); 1594 1595 return 1; 1596 } 1597 /* LDX: dst = *(size *)(src + off) */ 1598 case BPF_LDX | BPF_MEM | BPF_W: 1599 case BPF_LDX | BPF_MEM | BPF_H: 1600 case BPF_LDX | BPF_MEM | BPF_B: 1601 case BPF_LDX | BPF_MEM | BPF_DW: 1602 rn = arm_bpf_get_reg32(src_lo, tmp2[1], ctx); 1603 emit_ldx_r(dst, rn, off, ctx, BPF_SIZE(code)); 1604 break; 1605 /* ST: *(size *)(dst + off) = imm */ 1606 case BPF_ST | BPF_MEM | BPF_W: 1607 case BPF_ST | BPF_MEM | BPF_H: 1608 case BPF_ST | BPF_MEM | BPF_B: 1609 case BPF_ST | BPF_MEM | BPF_DW: 1610 switch (BPF_SIZE(code)) { 1611 case BPF_DW: 1612 /* Sign-extend immediate value into temp reg */ 1613 emit_a32_mov_se_i64(true, tmp2, imm, ctx); 1614 break; 1615 case BPF_W: 1616 case BPF_H: 1617 case BPF_B: 1618 emit_a32_mov_i(tmp2[1], imm, ctx); 1619 break; 1620 } 1621 emit_str_r(dst_lo, tmp2, off, ctx, BPF_SIZE(code)); 1622 break; 1623 /* STX XADD: lock *(u32 *)(dst + off) += src */ 1624 case BPF_STX | BPF_XADD | BPF_W: 1625 /* STX XADD: lock *(u64 *)(dst + off) += src */ 1626 case BPF_STX | BPF_XADD | BPF_DW: 1627 goto notyet; 1628 /* STX: *(size *)(dst + off) = src */ 1629 case BPF_STX | BPF_MEM | BPF_W: 1630 case BPF_STX | BPF_MEM | BPF_H: 1631 case BPF_STX | BPF_MEM | BPF_B: 1632 case BPF_STX | BPF_MEM | BPF_DW: 1633 rs = arm_bpf_get_reg64(src, tmp2, ctx); 1634 emit_str_r(dst_lo, rs, off, ctx, BPF_SIZE(code)); 1635 break; 1636 /* PC += off if dst == src */ 1637 /* PC += off if dst > src */ 1638 /* PC += off if dst >= src */ 1639 /* PC += off if dst < src */ 1640 /* PC += off if dst <= src */ 1641 /* PC += off if dst != src */ 1642 /* PC += off if dst > src (signed) */ 1643 /* PC += off if dst >= src (signed) */ 1644 /* PC += off if dst < src (signed) */ 1645 /* PC += off if dst <= src (signed) */ 1646 /* PC += off if dst & src */ 1647 case BPF_JMP | BPF_JEQ | BPF_X: 1648 case BPF_JMP | BPF_JGT | BPF_X: 1649 case BPF_JMP | BPF_JGE | BPF_X: 1650 case BPF_JMP | BPF_JNE | BPF_X: 1651 case BPF_JMP | BPF_JSGT | BPF_X: 1652 case BPF_JMP | BPF_JSGE | BPF_X: 1653 case BPF_JMP | BPF_JSET | BPF_X: 1654 case BPF_JMP | BPF_JLE | BPF_X: 1655 case BPF_JMP | BPF_JLT | BPF_X: 1656 case BPF_JMP | BPF_JSLT | BPF_X: 1657 case BPF_JMP | BPF_JSLE | BPF_X: 1658 case BPF_JMP32 | BPF_JEQ | BPF_X: 1659 case BPF_JMP32 | BPF_JGT | BPF_X: 1660 case BPF_JMP32 | BPF_JGE | BPF_X: 1661 case BPF_JMP32 | BPF_JNE | BPF_X: 1662 case BPF_JMP32 | BPF_JSGT | BPF_X: 1663 case BPF_JMP32 | BPF_JSGE | BPF_X: 1664 case BPF_JMP32 | BPF_JSET | BPF_X: 1665 case BPF_JMP32 | BPF_JLE | BPF_X: 1666 case BPF_JMP32 | BPF_JLT | BPF_X: 1667 case BPF_JMP32 | BPF_JSLT | BPF_X: 1668 case BPF_JMP32 | BPF_JSLE | BPF_X: 1669 /* Setup source registers */ 1670 rm = arm_bpf_get_reg32(src_hi, tmp2[0], ctx); 1671 rn = arm_bpf_get_reg32(src_lo, tmp2[1], ctx); 1672 goto go_jmp; 1673 /* PC += off if dst == imm */ 1674 /* PC += off if dst > imm */ 1675 /* PC += off if dst >= imm */ 1676 /* PC += off if dst < imm */ 1677 /* PC += off if dst <= imm */ 1678 /* PC += off if dst != imm */ 1679 /* PC += off if dst > imm (signed) */ 1680 /* PC += off if dst >= imm (signed) */ 1681 /* PC += off if dst < imm (signed) */ 1682 /* PC += off if dst <= imm (signed) */ 1683 /* PC += off if dst & imm */ 1684 case BPF_JMP | BPF_JEQ | BPF_K: 1685 case BPF_JMP | BPF_JGT | BPF_K: 1686 case BPF_JMP | BPF_JGE | BPF_K: 1687 case BPF_JMP | BPF_JNE | BPF_K: 1688 case BPF_JMP | BPF_JSGT | BPF_K: 1689 case BPF_JMP | BPF_JSGE | BPF_K: 1690 case BPF_JMP | BPF_JSET | BPF_K: 1691 case BPF_JMP | BPF_JLT | BPF_K: 1692 case BPF_JMP | BPF_JLE | BPF_K: 1693 case BPF_JMP | BPF_JSLT | BPF_K: 1694 case BPF_JMP | BPF_JSLE | BPF_K: 1695 case BPF_JMP32 | BPF_JEQ | BPF_K: 1696 case BPF_JMP32 | BPF_JGT | BPF_K: 1697 case BPF_JMP32 | BPF_JGE | BPF_K: 1698 case BPF_JMP32 | BPF_JNE | BPF_K: 1699 case BPF_JMP32 | BPF_JSGT | BPF_K: 1700 case BPF_JMP32 | BPF_JSGE | BPF_K: 1701 case BPF_JMP32 | BPF_JSET | BPF_K: 1702 case BPF_JMP32 | BPF_JLT | BPF_K: 1703 case BPF_JMP32 | BPF_JLE | BPF_K: 1704 case BPF_JMP32 | BPF_JSLT | BPF_K: 1705 case BPF_JMP32 | BPF_JSLE | BPF_K: 1706 if (off == 0) 1707 break; 1708 rm = tmp2[0]; 1709 rn = tmp2[1]; 1710 /* Sign-extend immediate value */ 1711 emit_a32_mov_se_i64(true, tmp2, imm, ctx); 1712 go_jmp: 1713 /* Setup destination register */ 1714 rd = arm_bpf_get_reg64(dst, tmp, ctx); 1715 1716 /* Check for the condition */ 1717 emit_ar_r(rd[0], rd[1], rm, rn, ctx, BPF_OP(code), 1718 BPF_CLASS(code) == BPF_JMP); 1719 1720 /* Setup JUMP instruction */ 1721 jmp_offset = bpf2a32_offset(i+off, i, ctx); 1722 switch (BPF_OP(code)) { 1723 case BPF_JNE: 1724 case BPF_JSET: 1725 _emit(ARM_COND_NE, ARM_B(jmp_offset), ctx); 1726 break; 1727 case BPF_JEQ: 1728 _emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx); 1729 break; 1730 case BPF_JGT: 1731 _emit(ARM_COND_HI, ARM_B(jmp_offset), ctx); 1732 break; 1733 case BPF_JGE: 1734 _emit(ARM_COND_CS, ARM_B(jmp_offset), ctx); 1735 break; 1736 case BPF_JSGT: 1737 _emit(ARM_COND_LT, ARM_B(jmp_offset), ctx); 1738 break; 1739 case BPF_JSGE: 1740 _emit(ARM_COND_GE, ARM_B(jmp_offset), ctx); 1741 break; 1742 case BPF_JLE: 1743 _emit(ARM_COND_LS, ARM_B(jmp_offset), ctx); 1744 break; 1745 case BPF_JLT: 1746 _emit(ARM_COND_CC, ARM_B(jmp_offset), ctx); 1747 break; 1748 case BPF_JSLT: 1749 _emit(ARM_COND_LT, ARM_B(jmp_offset), ctx); 1750 break; 1751 case BPF_JSLE: 1752 _emit(ARM_COND_GE, ARM_B(jmp_offset), ctx); 1753 break; 1754 } 1755 break; 1756 /* JMP OFF */ 1757 case BPF_JMP | BPF_JA: 1758 { 1759 if (off == 0) 1760 break; 1761 jmp_offset = bpf2a32_offset(i+off, i, ctx); 1762 check_imm24(jmp_offset); 1763 emit(ARM_B(jmp_offset), ctx); 1764 break; 1765 } 1766 /* tail call */ 1767 case BPF_JMP | BPF_TAIL_CALL: 1768 if (emit_bpf_tail_call(ctx)) 1769 return -EFAULT; 1770 break; 1771 /* function call */ 1772 case BPF_JMP | BPF_CALL: 1773 { 1774 const s8 *r0 = bpf2a32[BPF_REG_0]; 1775 const s8 *r1 = bpf2a32[BPF_REG_1]; 1776 const s8 *r2 = bpf2a32[BPF_REG_2]; 1777 const s8 *r3 = bpf2a32[BPF_REG_3]; 1778 const s8 *r4 = bpf2a32[BPF_REG_4]; 1779 const s8 *r5 = bpf2a32[BPF_REG_5]; 1780 const u32 func = (u32)__bpf_call_base + (u32)imm; 1781 1782 emit_a32_mov_r64(true, r0, r1, ctx); 1783 emit_a32_mov_r64(true, r1, r2, ctx); 1784 emit_push_r64(r5, ctx); 1785 emit_push_r64(r4, ctx); 1786 emit_push_r64(r3, ctx); 1787 1788 emit_a32_mov_i(tmp[1], func, ctx); 1789 emit_blx_r(tmp[1], ctx); 1790 1791 emit(ARM_ADD_I(ARM_SP, ARM_SP, imm8m(24)), ctx); // callee clean 1792 break; 1793 } 1794 /* function return */ 1795 case BPF_JMP | BPF_EXIT: 1796 /* Optimization: when last instruction is EXIT 1797 * simply fallthrough to epilogue. 1798 */ 1799 if (i == ctx->prog->len - 1) 1800 break; 1801 jmp_offset = epilogue_offset(ctx); 1802 check_imm24(jmp_offset); 1803 emit(ARM_B(jmp_offset), ctx); 1804 break; 1805 notyet: 1806 pr_info_once("*** NOT YET: opcode %02x ***\n", code); 1807 return -EFAULT; 1808 default: 1809 pr_err_once("unknown opcode %02x\n", code); 1810 return -EINVAL; 1811 } 1812 1813 if (ctx->flags & FLAG_IMM_OVERFLOW) 1814 /* 1815 * this instruction generated an overflow when 1816 * trying to access the literal pool, so 1817 * delegate this filter to the kernel interpreter. 1818 */ 1819 return -1; 1820 return 0; 1821 } 1822 1823 static int build_body(struct jit_ctx *ctx) 1824 { 1825 const struct bpf_prog *prog = ctx->prog; 1826 unsigned int i; 1827 1828 for (i = 0; i < prog->len; i++) { 1829 const struct bpf_insn *insn = &(prog->insnsi[i]); 1830 int ret; 1831 1832 ret = build_insn(insn, ctx); 1833 1834 /* It's used with loading the 64 bit immediate value. */ 1835 if (ret > 0) { 1836 i++; 1837 if (ctx->target == NULL) 1838 ctx->offsets[i] = ctx->idx; 1839 continue; 1840 } 1841 1842 if (ctx->target == NULL) 1843 ctx->offsets[i] = ctx->idx; 1844 1845 /* If unsuccesfull, return with error code */ 1846 if (ret) 1847 return ret; 1848 } 1849 return 0; 1850 } 1851 1852 static int validate_code(struct jit_ctx *ctx) 1853 { 1854 int i; 1855 1856 for (i = 0; i < ctx->idx; i++) { 1857 if (ctx->target[i] == __opcode_to_mem_arm(ARM_INST_UDF)) 1858 return -1; 1859 } 1860 1861 return 0; 1862 } 1863 1864 void bpf_jit_compile(struct bpf_prog *prog) 1865 { 1866 /* Nothing to do here. We support Internal BPF. */ 1867 } 1868 1869 bool bpf_jit_needs_zext(void) 1870 { 1871 return true; 1872 } 1873 1874 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) 1875 { 1876 struct bpf_prog *tmp, *orig_prog = prog; 1877 struct bpf_binary_header *header; 1878 bool tmp_blinded = false; 1879 struct jit_ctx ctx; 1880 unsigned int tmp_idx; 1881 unsigned int image_size; 1882 u8 *image_ptr; 1883 1884 /* If BPF JIT was not enabled then we must fall back to 1885 * the interpreter. 1886 */ 1887 if (!prog->jit_requested) 1888 return orig_prog; 1889 1890 /* If constant blinding was enabled and we failed during blinding 1891 * then we must fall back to the interpreter. Otherwise, we save 1892 * the new JITed code. 1893 */ 1894 tmp = bpf_jit_blind_constants(prog); 1895 1896 if (IS_ERR(tmp)) 1897 return orig_prog; 1898 if (tmp != prog) { 1899 tmp_blinded = true; 1900 prog = tmp; 1901 } 1902 1903 memset(&ctx, 0, sizeof(ctx)); 1904 ctx.prog = prog; 1905 ctx.cpu_architecture = cpu_architecture(); 1906 1907 /* Not able to allocate memory for offsets[] , then 1908 * we must fall back to the interpreter 1909 */ 1910 ctx.offsets = kcalloc(prog->len, sizeof(int), GFP_KERNEL); 1911 if (ctx.offsets == NULL) { 1912 prog = orig_prog; 1913 goto out; 1914 } 1915 1916 /* 1) fake pass to find in the length of the JITed code, 1917 * to compute ctx->offsets and other context variables 1918 * needed to compute final JITed code. 1919 * Also, calculate random starting pointer/start of JITed code 1920 * which is prefixed by random number of fault instructions. 1921 * 1922 * If the first pass fails then there is no chance of it 1923 * being successful in the second pass, so just fall back 1924 * to the interpreter. 1925 */ 1926 if (build_body(&ctx)) { 1927 prog = orig_prog; 1928 goto out_off; 1929 } 1930 1931 tmp_idx = ctx.idx; 1932 build_prologue(&ctx); 1933 ctx.prologue_bytes = (ctx.idx - tmp_idx) * 4; 1934 1935 ctx.epilogue_offset = ctx.idx; 1936 1937 #if __LINUX_ARM_ARCH__ < 7 1938 tmp_idx = ctx.idx; 1939 build_epilogue(&ctx); 1940 ctx.epilogue_bytes = (ctx.idx - tmp_idx) * 4; 1941 1942 ctx.idx += ctx.imm_count; 1943 if (ctx.imm_count) { 1944 ctx.imms = kcalloc(ctx.imm_count, sizeof(u32), GFP_KERNEL); 1945 if (ctx.imms == NULL) { 1946 prog = orig_prog; 1947 goto out_off; 1948 } 1949 } 1950 #else 1951 /* there's nothing about the epilogue on ARMv7 */ 1952 build_epilogue(&ctx); 1953 #endif 1954 /* Now we can get the actual image size of the JITed arm code. 1955 * Currently, we are not considering the THUMB-2 instructions 1956 * for jit, although it can decrease the size of the image. 1957 * 1958 * As each arm instruction is of length 32bit, we are translating 1959 * number of JITed intructions into the size required to store these 1960 * JITed code. 1961 */ 1962 image_size = sizeof(u32) * ctx.idx; 1963 1964 /* Now we know the size of the structure to make */ 1965 header = bpf_jit_binary_alloc(image_size, &image_ptr, 1966 sizeof(u32), jit_fill_hole); 1967 /* Not able to allocate memory for the structure then 1968 * we must fall back to the interpretation 1969 */ 1970 if (header == NULL) { 1971 prog = orig_prog; 1972 goto out_imms; 1973 } 1974 1975 /* 2.) Actual pass to generate final JIT code */ 1976 ctx.target = (u32 *) image_ptr; 1977 ctx.idx = 0; 1978 1979 build_prologue(&ctx); 1980 1981 /* If building the body of the JITed code fails somehow, 1982 * we fall back to the interpretation. 1983 */ 1984 if (build_body(&ctx) < 0) { 1985 image_ptr = NULL; 1986 bpf_jit_binary_free(header); 1987 prog = orig_prog; 1988 goto out_imms; 1989 } 1990 build_epilogue(&ctx); 1991 1992 /* 3.) Extra pass to validate JITed Code */ 1993 if (validate_code(&ctx)) { 1994 image_ptr = NULL; 1995 bpf_jit_binary_free(header); 1996 prog = orig_prog; 1997 goto out_imms; 1998 } 1999 flush_icache_range((u32)header, (u32)(ctx.target + ctx.idx)); 2000 2001 if (bpf_jit_enable > 1) 2002 /* there are 2 passes here */ 2003 bpf_jit_dump(prog->len, image_size, 2, ctx.target); 2004 2005 bpf_jit_binary_lock_ro(header); 2006 prog->bpf_func = (void *)ctx.target; 2007 prog->jited = 1; 2008 prog->jited_len = image_size; 2009 2010 out_imms: 2011 #if __LINUX_ARM_ARCH__ < 7 2012 if (ctx.imm_count) 2013 kfree(ctx.imms); 2014 #endif 2015 out_off: 2016 kfree(ctx.offsets); 2017 out: 2018 if (tmp_blinded) 2019 bpf_jit_prog_release_other(prog, prog == orig_prog ? 2020 tmp : orig_prog); 2021 return prog; 2022 } 2023 2024