// SPDX-License-Identifier: GPL-2.0-only /* * Just-In-Time compiler for eBPF filters on 32bit ARM * * Copyright (c) 2017 Shubham Bansal * Copyright (c) 2011 Mircea Gherzan */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include "bpf_jit_32.h" /* * eBPF prog stack layout: * * high * original ARM_SP => +-----+ * | | callee saved registers * +-----+ <= (BPF_FP + SCRATCH_SIZE) * | ... | eBPF JIT scratch space * eBPF fp register => +-----+ * (BPF_FP) | ... | eBPF prog stack * +-----+ * |RSVD | JIT scratchpad * current ARM_SP => +-----+ <= (BPF_FP - STACK_SIZE + SCRATCH_SIZE) * | ... | caller-saved registers * +-----+ * | ... | arguments passed on stack * ARM_SP during call => +-----| * | | * | ... | Function call stack * | | * +-----+ * low * * The callee saved registers depends on whether frame pointers are enabled. * With frame pointers (to be compliant with the ABI): * * high * original ARM_SP => +--------------+ \ * | pc | | * current ARM_FP => +--------------+ } callee saved registers * |r4-r9,fp,ip,lr| | * +--------------+ / * low * * Without frame pointers: * * high * original ARM_SP => +--------------+ * | r4-r9,fp,lr | callee saved registers * current ARM_FP => +--------------+ * low * * When popping registers off the stack at the end of a BPF function, we * reference them via the current ARM_FP register. * * Some eBPF operations are implemented via a call to a helper function. * Such calls are "invisible" in the eBPF code, so it is up to the calling * program to preserve any caller-saved ARM registers during the call. The * JIT emits code to push and pop those registers onto the stack, immediately * above the callee stack frame. */ #define CALLEE_MASK (1 << ARM_R4 | 1 << ARM_R5 | 1 << ARM_R6 | \ 1 << ARM_R7 | 1 << ARM_R8 | 1 << ARM_R9 | \ 1 << ARM_FP) #define CALLEE_PUSH_MASK (CALLEE_MASK | 1 << ARM_LR) #define CALLEE_POP_MASK (CALLEE_MASK | 1 << ARM_PC) #define CALLER_MASK (1 << ARM_R0 | 1 << ARM_R1 | 1 << ARM_R2 | 1 << ARM_R3) enum { /* Stack layout - these are offsets from (top of stack - 4) */ BPF_R2_HI, BPF_R2_LO, BPF_R3_HI, BPF_R3_LO, BPF_R4_HI, BPF_R4_LO, BPF_R5_HI, BPF_R5_LO, BPF_R7_HI, BPF_R7_LO, BPF_R8_HI, BPF_R8_LO, BPF_R9_HI, BPF_R9_LO, BPF_FP_HI, BPF_FP_LO, BPF_TC_HI, BPF_TC_LO, BPF_AX_HI, BPF_AX_LO, /* Stack space for BPF_REG_2, BPF_REG_3, BPF_REG_4, * BPF_REG_5, BPF_REG_7, BPF_REG_8, BPF_REG_9, * BPF_REG_FP and Tail call counts. */ BPF_JIT_SCRATCH_REGS, }; /* * Negative "register" values indicate the register is stored on the stack * and are the offset from the top of the eBPF JIT scratch space. */ #define STACK_OFFSET(k) (-4 - (k) * 4) #define SCRATCH_SIZE (BPF_JIT_SCRATCH_REGS * 4) #ifdef CONFIG_FRAME_POINTER #define EBPF_SCRATCH_TO_ARM_FP(x) ((x) - 4 * hweight16(CALLEE_PUSH_MASK) - 4) #else #define EBPF_SCRATCH_TO_ARM_FP(x) (x) #endif #define TMP_REG_1 (MAX_BPF_JIT_REG + 0) /* TEMP Register 1 */ #define TMP_REG_2 (MAX_BPF_JIT_REG + 1) /* TEMP Register 2 */ #define TCALL_CNT (MAX_BPF_JIT_REG + 2) /* Tail Call Count */ #define FLAG_IMM_OVERFLOW (1 << 0) /* * Map eBPF registers to ARM 32bit registers or stack scratch space. * * 1. First argument is passed using the arm 32bit registers and rest of the * arguments are passed on stack scratch space. * 2. First callee-saved argument is mapped to arm 32 bit registers and rest * arguments are mapped to scratch space on stack. * 3. We need two 64 bit temp registers to do complex operations on eBPF * registers. * * As the eBPF registers are all 64 bit registers and arm has only 32 bit * registers, we have to map each eBPF registers with two arm 32 bit regs or * scratch memory space and we have to build eBPF 64 bit register from those. * */ static const s8 bpf2a32[][2] = { /* return value from in-kernel function, and exit value from eBPF */ [BPF_REG_0] = {ARM_R1, ARM_R0}, /* arguments from eBPF program to in-kernel function */ [BPF_REG_1] = {ARM_R3, ARM_R2}, /* Stored on stack scratch space */ [BPF_REG_2] = {STACK_OFFSET(BPF_R2_HI), STACK_OFFSET(BPF_R2_LO)}, [BPF_REG_3] = {STACK_OFFSET(BPF_R3_HI), STACK_OFFSET(BPF_R3_LO)}, [BPF_REG_4] = {STACK_OFFSET(BPF_R4_HI), STACK_OFFSET(BPF_R4_LO)}, [BPF_REG_5] = {STACK_OFFSET(BPF_R5_HI), STACK_OFFSET(BPF_R5_LO)}, /* callee saved registers that in-kernel function will preserve */ [BPF_REG_6] = {ARM_R5, ARM_R4}, /* Stored on stack scratch space */ [BPF_REG_7] = {STACK_OFFSET(BPF_R7_HI), STACK_OFFSET(BPF_R7_LO)}, [BPF_REG_8] = {STACK_OFFSET(BPF_R8_HI), STACK_OFFSET(BPF_R8_LO)}, [BPF_REG_9] = {STACK_OFFSET(BPF_R9_HI), STACK_OFFSET(BPF_R9_LO)}, /* Read only Frame Pointer to access Stack */ [BPF_REG_FP] = {STACK_OFFSET(BPF_FP_HI), STACK_OFFSET(BPF_FP_LO)}, /* Temporary Register for internal BPF JIT, can be used * for constant blindings and others. */ [TMP_REG_1] = {ARM_R7, ARM_R6}, [TMP_REG_2] = {ARM_R9, ARM_R8}, /* Tail call count. Stored on stack scratch space. */ [TCALL_CNT] = {STACK_OFFSET(BPF_TC_HI), STACK_OFFSET(BPF_TC_LO)}, /* temporary register for blinding constants. * Stored on stack scratch space. */ [BPF_REG_AX] = {STACK_OFFSET(BPF_AX_HI), STACK_OFFSET(BPF_AX_LO)}, }; #define dst_lo dst[1] #define dst_hi dst[0] #define src_lo src[1] #define src_hi src[0] /* * JIT Context: * * prog : bpf_prog * idx : index of current last JITed instruction. * prologue_bytes : bytes used in prologue. * epilogue_offset : offset of epilogue starting. * offsets : array of eBPF instruction offsets in * JITed code. * target : final JITed code. * epilogue_bytes : no of bytes used in epilogue. * imm_count : no of immediate counts used for global * variables. * imms : array of global variable addresses. */ struct jit_ctx { const struct bpf_prog *prog; unsigned int idx; unsigned int prologue_bytes; unsigned int epilogue_offset; unsigned int cpu_architecture; u32 flags; u32 *offsets; u32 *target; u32 stack_size; #if __LINUX_ARM_ARCH__ < 7 u16 epilogue_bytes; u16 imm_count; u32 *imms; #endif }; /* * Wrappers which handle both OABI and EABI and assures Thumb2 interworking * (where the assembly routines like __aeabi_uidiv could cause problems). */ static u32 jit_udiv32(u32 dividend, u32 divisor) { return dividend / divisor; } static u32 jit_mod32(u32 dividend, u32 divisor) { return dividend % divisor; } static inline void _emit(int cond, u32 inst, struct jit_ctx *ctx) { inst |= (cond << 28); inst = __opcode_to_mem_arm(inst); if (ctx->target != NULL) ctx->target[ctx->idx] = inst; ctx->idx++; } /* * Emit an instruction that will be executed unconditionally. */ static inline void emit(u32 inst, struct jit_ctx *ctx) { _emit(ARM_COND_AL, inst, ctx); } /* * This is rather horrid, but necessary to convert an integer constant * to an immediate operand for the opcodes, and be able to detect at * build time whether the constant can't be converted (iow, usable in * BUILD_BUG_ON()). */ #define imm12val(v, s) (rol32(v, (s)) | (s) << 7) #define const_imm8m(x) \ ({ int r; \ u32 v = (x); \ if (!(v & ~0x000000ff)) \ r = imm12val(v, 0); \ else if (!(v & ~0xc000003f)) \ r = imm12val(v, 2); \ else if (!(v & ~0xf000000f)) \ r = imm12val(v, 4); \ else if (!(v & ~0xfc000003)) \ r = imm12val(v, 6); \ else if (!(v & ~0xff000000)) \ r = imm12val(v, 8); \ else if (!(v & ~0x3fc00000)) \ r = imm12val(v, 10); \ else if (!(v & ~0x0ff00000)) \ r = imm12val(v, 12); \ else if (!(v & ~0x03fc0000)) \ r = imm12val(v, 14); \ else if (!(v & ~0x00ff0000)) \ r = imm12val(v, 16); \ else if (!(v & ~0x003fc000)) \ r = imm12val(v, 18); \ else if (!(v & ~0x000ff000)) \ r = imm12val(v, 20); \ else if (!(v & ~0x0003fc00)) \ r = imm12val(v, 22); \ else if (!(v & ~0x0000ff00)) \ r = imm12val(v, 24); \ else if (!(v & ~0x00003fc0)) \ r = imm12val(v, 26); \ else if (!(v & ~0x00000ff0)) \ r = imm12val(v, 28); \ else if (!(v & ~0x000003fc)) \ r = imm12val(v, 30); \ else \ r = -1; \ r; }) /* * Checks if immediate value can be converted to imm12(12 bits) value. */ static int imm8m(u32 x) { u32 rot; for (rot = 0; rot < 16; rot++) if ((x & ~ror32(0xff, 2 * rot)) == 0) return rol32(x, 2 * rot) | (rot << 8); return -1; } #define imm8m(x) (__builtin_constant_p(x) ? const_imm8m(x) : imm8m(x)) static u32 arm_bpf_ldst_imm12(u32 op, u8 rt, u8 rn, s16 imm12) { op |= rt << 12 | rn << 16; if (imm12 >= 0) op |= ARM_INST_LDST__U; else imm12 = -imm12; return op | (imm12 & ARM_INST_LDST__IMM12); } static u32 arm_bpf_ldst_imm8(u32 op, u8 rt, u8 rn, s16 imm8) { op |= rt << 12 | rn << 16; if (imm8 >= 0) op |= ARM_INST_LDST__U; else imm8 = -imm8; return op | (imm8 & 0xf0) << 4 | (imm8 & 0x0f); } #define ARM_LDR_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_LDR_I, rt, rn, off) #define ARM_LDRB_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_LDRB_I, rt, rn, off) #define ARM_LDRD_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_LDRD_I, rt, rn, off) #define ARM_LDRH_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_LDRH_I, rt, rn, off) #define ARM_STR_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_STR_I, rt, rn, off) #define ARM_STRB_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_STRB_I, rt, rn, off) #define ARM_STRD_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_STRD_I, rt, rn, off) #define ARM_STRH_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_STRH_I, rt, rn, off) /* * Initializes the JIT space with undefined instructions. */ static void jit_fill_hole(void *area, unsigned int size) { u32 *ptr; /* We are guaranteed to have aligned memory. */ for (ptr = area; size >= sizeof(u32); size -= sizeof(u32)) *ptr++ = __opcode_to_mem_arm(ARM_INST_UDF); } #if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5) /* EABI requires the stack to be aligned to 64-bit boundaries */ #define STACK_ALIGNMENT 8 #else /* Stack must be aligned to 32-bit boundaries */ #define STACK_ALIGNMENT 4 #endif /* total stack size used in JITed code */ #define _STACK_SIZE (ctx->prog->aux->stack_depth + SCRATCH_SIZE) #define STACK_SIZE ALIGN(_STACK_SIZE, STACK_ALIGNMENT) #if __LINUX_ARM_ARCH__ < 7 static u16 imm_offset(u32 k, struct jit_ctx *ctx) { unsigned int i = 0, offset; u16 imm; /* on the "fake" run we just count them (duplicates included) */ if (ctx->target == NULL) { ctx->imm_count++; return 0; } while ((i < ctx->imm_count) && ctx->imms[i]) { if (ctx->imms[i] == k) break; i++; } if (ctx->imms[i] == 0) ctx->imms[i] = k; /* constants go just after the epilogue */ offset = ctx->offsets[ctx->prog->len - 1] * 4; offset += ctx->prologue_bytes; offset += ctx->epilogue_bytes; offset += i * 4; ctx->target[offset / 4] = k; /* PC in ARM mode == address of the instruction + 8 */ imm = offset - (8 + ctx->idx * 4); if (imm & ~0xfff) { /* * literal pool is too far, signal it into flags. we * can only detect it on the second pass unfortunately. */ ctx->flags |= FLAG_IMM_OVERFLOW; return 0; } return imm; } #endif /* __LINUX_ARM_ARCH__ */ static inline int bpf2a32_offset(int bpf_to, int bpf_from, const struct jit_ctx *ctx) { int to, from; if (ctx->target == NULL) return 0; to = ctx->offsets[bpf_to]; from = ctx->offsets[bpf_from]; return to - from - 1; } /* * Move an immediate that's not an imm8m to a core register. */ static inline void emit_mov_i_no8m(const u8 rd, u32 val, struct jit_ctx *ctx) { #if __LINUX_ARM_ARCH__ < 7 emit(ARM_LDR_I(rd, ARM_PC, imm_offset(val, ctx)), ctx); #else emit(ARM_MOVW(rd, val & 0xffff), ctx); if (val > 0xffff) emit(ARM_MOVT(rd, val >> 16), ctx); #endif } static inline void emit_mov_i(const u8 rd, u32 val, struct jit_ctx *ctx) { int imm12 = imm8m(val); if (imm12 >= 0) emit(ARM_MOV_I(rd, imm12), ctx); else emit_mov_i_no8m(rd, val, ctx); } static void emit_bx_r(u8 tgt_reg, struct jit_ctx *ctx) { if (elf_hwcap & HWCAP_THUMB) emit(ARM_BX(tgt_reg), ctx); else emit(ARM_MOV_R(ARM_PC, tgt_reg), ctx); } static inline void emit_blx_r(u8 tgt_reg, struct jit_ctx *ctx) { #if __LINUX_ARM_ARCH__ < 5 emit(ARM_MOV_R(ARM_LR, ARM_PC), ctx); emit_bx_r(tgt_reg, ctx); #else emit(ARM_BLX_R(tgt_reg), ctx); #endif } static inline int epilogue_offset(const struct jit_ctx *ctx) { int to, from; /* No need for 1st dummy run */ if (ctx->target == NULL) return 0; to = ctx->epilogue_offset; from = ctx->idx; return to - from - 2; } static inline void emit_udivmod(u8 rd, u8 rm, u8 rn, struct jit_ctx *ctx, u8 op) { const int exclude_mask = BIT(ARM_R0) | BIT(ARM_R1); const s8 *tmp = bpf2a32[TMP_REG_1]; #if __LINUX_ARM_ARCH__ == 7 if (elf_hwcap & HWCAP_IDIVA) { if (op == BPF_DIV) emit(ARM_UDIV(rd, rm, rn), ctx); else { emit(ARM_UDIV(ARM_IP, rm, rn), ctx); emit(ARM_MLS(rd, rn, ARM_IP, rm), ctx); } return; } #endif /* * For BPF_ALU | BPF_DIV | BPF_K instructions * As ARM_R1 and ARM_R0 contains 1st argument of bpf * function, we need to save it on caller side to save * it from getting destroyed within callee. * After the return from the callee, we restore ARM_R0 * ARM_R1. */ if (rn != ARM_R1) { emit(ARM_MOV_R(tmp[0], ARM_R1), ctx); emit(ARM_MOV_R(ARM_R1, rn), ctx); } if (rm != ARM_R0) { emit(ARM_MOV_R(tmp[1], ARM_R0), ctx); emit(ARM_MOV_R(ARM_R0, rm), ctx); } /* Push caller-saved registers on stack */ emit(ARM_PUSH(CALLER_MASK & ~exclude_mask), ctx); /* Call appropriate function */ emit_mov_i(ARM_IP, op == BPF_DIV ? (u32)jit_udiv32 : (u32)jit_mod32, ctx); emit_blx_r(ARM_IP, ctx); /* Restore caller-saved registers from stack */ emit(ARM_POP(CALLER_MASK & ~exclude_mask), ctx); /* Save return value */ if (rd != ARM_R0) emit(ARM_MOV_R(rd, ARM_R0), ctx); /* Restore ARM_R0 and ARM_R1 */ if (rn != ARM_R1) emit(ARM_MOV_R(ARM_R1, tmp[0]), ctx); if (rm != ARM_R0) emit(ARM_MOV_R(ARM_R0, tmp[1]), ctx); } /* Is the translated BPF register on stack? */ static bool is_stacked(s8 reg) { return reg < 0; } /* If a BPF register is on the stack (stk is true), load it to the * supplied temporary register and return the temporary register * for subsequent operations, otherwise just use the CPU register. */ static s8 arm_bpf_get_reg32(s8 reg, s8 tmp, struct jit_ctx *ctx) { if (is_stacked(reg)) { emit(ARM_LDR_I(tmp, ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg)), ctx); reg = tmp; } return reg; } static const s8 *arm_bpf_get_reg64(const s8 *reg, const s8 *tmp, struct jit_ctx *ctx) { if (is_stacked(reg[1])) { if (__LINUX_ARM_ARCH__ >= 6 || ctx->cpu_architecture >= CPU_ARCH_ARMv5TE) { emit(ARM_LDRD_I(tmp[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx); } else { emit(ARM_LDR_I(tmp[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx); emit(ARM_LDR_I(tmp[0], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg[0])), ctx); } reg = tmp; } return reg; } /* If a BPF register is on the stack (stk is true), save the register * back to the stack. If the source register is not the same, then * move it into the correct register. */ static void arm_bpf_put_reg32(s8 reg, s8 src, struct jit_ctx *ctx) { if (is_stacked(reg)) emit(ARM_STR_I(src, ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg)), ctx); else if (reg != src) emit(ARM_MOV_R(reg, src), ctx); } static void arm_bpf_put_reg64(const s8 *reg, const s8 *src, struct jit_ctx *ctx) { if (is_stacked(reg[1])) { if (__LINUX_ARM_ARCH__ >= 6 || ctx->cpu_architecture >= CPU_ARCH_ARMv5TE) { emit(ARM_STRD_I(src[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx); } else { emit(ARM_STR_I(src[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx); emit(ARM_STR_I(src[0], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg[0])), ctx); } } else { if (reg[1] != src[1]) emit(ARM_MOV_R(reg[1], src[1]), ctx); if (reg[0] != src[0]) emit(ARM_MOV_R(reg[0], src[0]), ctx); } } static inline void emit_a32_mov_i(const s8 dst, const u32 val, struct jit_ctx *ctx) { const s8 *tmp = bpf2a32[TMP_REG_1]; if (is_stacked(dst)) { emit_mov_i(tmp[1], val, ctx); arm_bpf_put_reg32(dst, tmp[1], ctx); } else { emit_mov_i(dst, val, ctx); } } static void emit_a32_mov_i64(const s8 dst[], u64 val, struct jit_ctx *ctx) { const s8 *tmp = bpf2a32[TMP_REG_1]; const s8 *rd = is_stacked(dst_lo) ? tmp : dst; emit_mov_i(rd[1], (u32)val, ctx); emit_mov_i(rd[0], val >> 32, ctx); arm_bpf_put_reg64(dst, rd, ctx); } /* Sign extended move */ static inline void emit_a32_mov_se_i64(const bool is64, const s8 dst[], const u32 val, struct jit_ctx *ctx) { u64 val64 = val; if (is64 && (val & (1<<31))) val64 |= 0xffffffff00000000ULL; emit_a32_mov_i64(dst, val64, ctx); } static inline void emit_a32_add_r(const u8 dst, const u8 src, const bool is64, const bool hi, struct jit_ctx *ctx) { /* 64 bit : * adds dst_lo, dst_lo, src_lo * adc dst_hi, dst_hi, src_hi * 32 bit : * add dst_lo, dst_lo, src_lo */ if (!hi && is64) emit(ARM_ADDS_R(dst, dst, src), ctx); else if (hi && is64) emit(ARM_ADC_R(dst, dst, src), ctx); else emit(ARM_ADD_R(dst, dst, src), ctx); } static inline void emit_a32_sub_r(const u8 dst, const u8 src, const bool is64, const bool hi, struct jit_ctx *ctx) { /* 64 bit : * subs dst_lo, dst_lo, src_lo * sbc dst_hi, dst_hi, src_hi * 32 bit : * sub dst_lo, dst_lo, src_lo */ if (!hi && is64) emit(ARM_SUBS_R(dst, dst, src), ctx); else if (hi && is64) emit(ARM_SBC_R(dst, dst, src), ctx); else emit(ARM_SUB_R(dst, dst, src), ctx); } static inline void emit_alu_r(const u8 dst, const u8 src, const bool is64, const bool hi, const u8 op, struct jit_ctx *ctx){ switch (BPF_OP(op)) { /* dst = dst + src */ case BPF_ADD: emit_a32_add_r(dst, src, is64, hi, ctx); break; /* dst = dst - src */ case BPF_SUB: emit_a32_sub_r(dst, src, is64, hi, ctx); break; /* dst = dst | src */ case BPF_OR: emit(ARM_ORR_R(dst, dst, src), ctx); break; /* dst = dst & src */ case BPF_AND: emit(ARM_AND_R(dst, dst, src), ctx); break; /* dst = dst ^ src */ case BPF_XOR: emit(ARM_EOR_R(dst, dst, src), ctx); break; /* dst = dst * src */ case BPF_MUL: emit(ARM_MUL(dst, dst, src), ctx); break; /* dst = dst << src */ case BPF_LSH: emit(ARM_LSL_R(dst, dst, src), ctx); break; /* dst = dst >> src */ case BPF_RSH: emit(ARM_LSR_R(dst, dst, src), ctx); break; /* dst = dst >> src (signed)*/ case BPF_ARSH: emit(ARM_MOV_SR(dst, dst, SRTYPE_ASR, src), ctx); break; } } /* ALU operation (32 bit) * dst = dst (op) src */ static inline void emit_a32_alu_r(const s8 dst, const s8 src, struct jit_ctx *ctx, const bool is64, const bool hi, const u8 op) { const s8 *tmp = bpf2a32[TMP_REG_1]; s8 rn, rd; rn = arm_bpf_get_reg32(src, tmp[1], ctx); rd = arm_bpf_get_reg32(dst, tmp[0], ctx); /* ALU operation */ emit_alu_r(rd, rn, is64, hi, op, ctx); arm_bpf_put_reg32(dst, rd, ctx); } /* ALU operation (64 bit) */ static inline void emit_a32_alu_r64(const bool is64, const s8 dst[], const s8 src[], struct jit_ctx *ctx, const u8 op) { const s8 *tmp = bpf2a32[TMP_REG_1]; const s8 *tmp2 = bpf2a32[TMP_REG_2]; const s8 *rd; rd = arm_bpf_get_reg64(dst, tmp, ctx); if (is64) { const s8 *rs; rs = arm_bpf_get_reg64(src, tmp2, ctx); /* ALU operation */ emit_alu_r(rd[1], rs[1], true, false, op, ctx); emit_alu_r(rd[0], rs[0], true, true, op, ctx); } else { s8 rs; rs = arm_bpf_get_reg32(src_lo, tmp2[1], ctx); /* ALU operation */ emit_alu_r(rd[1], rs, true, false, op, ctx); if (!ctx->prog->aux->verifier_zext) emit_a32_mov_i(rd[0], 0, ctx); } arm_bpf_put_reg64(dst, rd, ctx); } /* dst = src (4 bytes)*/ static inline void emit_a32_mov_r(const s8 dst, const s8 src, struct jit_ctx *ctx) { const s8 *tmp = bpf2a32[TMP_REG_1]; s8 rt; rt = arm_bpf_get_reg32(src, tmp[0], ctx); arm_bpf_put_reg32(dst, rt, ctx); } /* dst = src */ static inline void emit_a32_mov_r64(const bool is64, const s8 dst[], const s8 src[], struct jit_ctx *ctx) { if (!is64) { emit_a32_mov_r(dst_lo, src_lo, ctx); if (!ctx->prog->aux->verifier_zext) /* Zero out high 4 bytes */ emit_a32_mov_i(dst_hi, 0, ctx); } else if (__LINUX_ARM_ARCH__ < 6 && ctx->cpu_architecture < CPU_ARCH_ARMv5TE) { /* complete 8 byte move */ emit_a32_mov_r(dst_lo, src_lo, ctx); emit_a32_mov_r(dst_hi, src_hi, ctx); } else if (is_stacked(src_lo) && is_stacked(dst_lo)) { const u8 *tmp = bpf2a32[TMP_REG_1]; emit(ARM_LDRD_I(tmp[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(src_lo)), ctx); emit(ARM_STRD_I(tmp[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(dst_lo)), ctx); } else if (is_stacked(src_lo)) { emit(ARM_LDRD_I(dst[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(src_lo)), ctx); } else if (is_stacked(dst_lo)) { emit(ARM_STRD_I(src[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(dst_lo)), ctx); } else { emit(ARM_MOV_R(dst[0], src[0]), ctx); emit(ARM_MOV_R(dst[1], src[1]), ctx); } } /* Shift operations */ static inline void emit_a32_alu_i(const s8 dst, const u32 val, struct jit_ctx *ctx, const u8 op) { const s8 *tmp = bpf2a32[TMP_REG_1]; s8 rd; rd = arm_bpf_get_reg32(dst, tmp[0], ctx); /* Do shift operation */ switch (op) { case BPF_LSH: emit(ARM_LSL_I(rd, rd, val), ctx); break; case BPF_RSH: emit(ARM_LSR_I(rd, rd, val), ctx); break; case BPF_ARSH: emit(ARM_ASR_I(rd, rd, val), ctx); break; case BPF_NEG: emit(ARM_RSB_I(rd, rd, val), ctx); break; } arm_bpf_put_reg32(dst, rd, ctx); } /* dst = ~dst (64 bit) */ static inline void emit_a32_neg64(const s8 dst[], struct jit_ctx *ctx){ const s8 *tmp = bpf2a32[TMP_REG_1]; const s8 *rd; /* Setup Operand */ rd = arm_bpf_get_reg64(dst, tmp, ctx); /* Do Negate Operation */ emit(ARM_RSBS_I(rd[1], rd[1], 0), ctx); emit(ARM_RSC_I(rd[0], rd[0], 0), ctx); arm_bpf_put_reg64(dst, rd, ctx); } /* dst = dst << src */ static inline void emit_a32_lsh_r64(const s8 dst[], const s8 src[], struct jit_ctx *ctx) { const s8 *tmp = bpf2a32[TMP_REG_1]; const s8 *tmp2 = bpf2a32[TMP_REG_2]; const s8 *rd; s8 rt; /* Setup Operands */ rt = arm_bpf_get_reg32(src_lo, tmp2[1], ctx); rd = arm_bpf_get_reg64(dst, tmp, ctx); /* Do LSH operation */ emit(ARM_SUB_I(ARM_IP, rt, 32), ctx); emit(ARM_RSB_I(tmp2[0], rt, 32), ctx); emit(ARM_MOV_SR(ARM_LR, rd[0], SRTYPE_ASL, rt), ctx); emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[1], SRTYPE_ASL, ARM_IP), ctx); emit(ARM_ORR_SR(ARM_IP, ARM_LR, rd[1], SRTYPE_LSR, tmp2[0]), ctx); emit(ARM_MOV_SR(ARM_LR, rd[1], SRTYPE_ASL, rt), ctx); arm_bpf_put_reg32(dst_lo, ARM_LR, ctx); arm_bpf_put_reg32(dst_hi, ARM_IP, ctx); } /* dst = dst >> src (signed)*/ static inline void emit_a32_arsh_r64(const s8 dst[], const s8 src[], struct jit_ctx *ctx) { const s8 *tmp = bpf2a32[TMP_REG_1]; const s8 *tmp2 = bpf2a32[TMP_REG_2]; const s8 *rd; s8 rt; /* Setup Operands */ rt = arm_bpf_get_reg32(src_lo, tmp2[1], ctx); rd = arm_bpf_get_reg64(dst, tmp, ctx); /* Do the ARSH operation */ emit(ARM_RSB_I(ARM_IP, rt, 32), ctx); emit(ARM_SUBS_I(tmp2[0], rt, 32), ctx); emit(ARM_MOV_SR(ARM_LR, rd[1], SRTYPE_LSR, rt), ctx); emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASL, ARM_IP), ctx); _emit(ARM_COND_PL, ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASR, tmp2[0]), ctx); emit(ARM_MOV_SR(ARM_IP, rd[0], SRTYPE_ASR, rt), ctx); arm_bpf_put_reg32(dst_lo, ARM_LR, ctx); arm_bpf_put_reg32(dst_hi, ARM_IP, ctx); } /* dst = dst >> src */ static inline void emit_a32_rsh_r64(const s8 dst[], const s8 src[], struct jit_ctx *ctx) { const s8 *tmp = bpf2a32[TMP_REG_1]; const s8 *tmp2 = bpf2a32[TMP_REG_2]; const s8 *rd; s8 rt; /* Setup Operands */ rt = arm_bpf_get_reg32(src_lo, tmp2[1], ctx); rd = arm_bpf_get_reg64(dst, tmp, ctx); /* Do RSH operation */ emit(ARM_RSB_I(ARM_IP, rt, 32), ctx); emit(ARM_SUBS_I(tmp2[0], rt, 32), ctx); emit(ARM_MOV_SR(ARM_LR, rd[1], SRTYPE_LSR, rt), ctx); emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASL, ARM_IP), ctx); emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_LSR, tmp2[0]), ctx); emit(ARM_MOV_SR(ARM_IP, rd[0], SRTYPE_LSR, rt), ctx); arm_bpf_put_reg32(dst_lo, ARM_LR, ctx); arm_bpf_put_reg32(dst_hi, ARM_IP, ctx); } /* dst = dst << val */ static inline void emit_a32_lsh_i64(const s8 dst[], const u32 val, struct jit_ctx *ctx){ const s8 *tmp = bpf2a32[TMP_REG_1]; const s8 *tmp2 = bpf2a32[TMP_REG_2]; const s8 *rd; /* Setup operands */ rd = arm_bpf_get_reg64(dst, tmp, ctx); /* Do LSH operation */ if (val < 32) { emit(ARM_MOV_SI(tmp2[0], rd[0], SRTYPE_ASL, val), ctx); emit(ARM_ORR_SI(rd[0], tmp2[0], rd[1], SRTYPE_LSR, 32 - val), ctx); emit(ARM_MOV_SI(rd[1], rd[1], SRTYPE_ASL, val), ctx); } else { if (val == 32) emit(ARM_MOV_R(rd[0], rd[1]), ctx); else emit(ARM_MOV_SI(rd[0], rd[1], SRTYPE_ASL, val - 32), ctx); emit(ARM_EOR_R(rd[1], rd[1], rd[1]), ctx); } arm_bpf_put_reg64(dst, rd, ctx); } /* dst = dst >> val */ static inline void emit_a32_rsh_i64(const s8 dst[], const u32 val, struct jit_ctx *ctx) { const s8 *tmp = bpf2a32[TMP_REG_1]; const s8 *tmp2 = bpf2a32[TMP_REG_2]; const s8 *rd; /* Setup operands */ rd = arm_bpf_get_reg64(dst, tmp, ctx); /* Do LSR operation */ if (val == 0) { /* An immediate value of 0 encodes a shift amount of 32 * for LSR. To shift by 0, don't do anything. */ } else if (val < 32) { emit(ARM_MOV_SI(tmp2[1], rd[1], SRTYPE_LSR, val), ctx); emit(ARM_ORR_SI(rd[1], tmp2[1], rd[0], SRTYPE_ASL, 32 - val), ctx); emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_LSR, val), ctx); } else if (val == 32) { emit(ARM_MOV_R(rd[1], rd[0]), ctx); emit(ARM_MOV_I(rd[0], 0), ctx); } else { emit(ARM_MOV_SI(rd[1], rd[0], SRTYPE_LSR, val - 32), ctx); emit(ARM_MOV_I(rd[0], 0), ctx); } arm_bpf_put_reg64(dst, rd, ctx); } /* dst = dst >> val (signed) */ static inline void emit_a32_arsh_i64(const s8 dst[], const u32 val, struct jit_ctx *ctx){ const s8 *tmp = bpf2a32[TMP_REG_1]; const s8 *tmp2 = bpf2a32[TMP_REG_2]; const s8 *rd; /* Setup operands */ rd = arm_bpf_get_reg64(dst, tmp, ctx); /* Do ARSH operation */ if (val == 0) { /* An immediate value of 0 encodes a shift amount of 32 * for ASR. To shift by 0, don't do anything. */ } else if (val < 32) { emit(ARM_MOV_SI(tmp2[1], rd[1], SRTYPE_LSR, val), ctx); emit(ARM_ORR_SI(rd[1], tmp2[1], rd[0], SRTYPE_ASL, 32 - val), ctx); emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_ASR, val), ctx); } else if (val == 32) { emit(ARM_MOV_R(rd[1], rd[0]), ctx); emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_ASR, 31), ctx); } else { emit(ARM_MOV_SI(rd[1], rd[0], SRTYPE_ASR, val - 32), ctx); emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_ASR, 31), ctx); } arm_bpf_put_reg64(dst, rd, ctx); } static inline void emit_a32_mul_r64(const s8 dst[], const s8 src[], struct jit_ctx *ctx) { const s8 *tmp = bpf2a32[TMP_REG_1]; const s8 *tmp2 = bpf2a32[TMP_REG_2]; const s8 *rd, *rt; /* Setup operands for multiplication */ rd = arm_bpf_get_reg64(dst, tmp, ctx); rt = arm_bpf_get_reg64(src, tmp2, ctx); /* Do Multiplication */ emit(ARM_MUL(ARM_IP, rd[1], rt[0]), ctx); emit(ARM_MUL(ARM_LR, rd[0], rt[1]), ctx); emit(ARM_ADD_R(ARM_LR, ARM_IP, ARM_LR), ctx); emit(ARM_UMULL(ARM_IP, rd[0], rd[1], rt[1]), ctx); emit(ARM_ADD_R(rd[0], ARM_LR, rd[0]), ctx); arm_bpf_put_reg32(dst_lo, ARM_IP, ctx); arm_bpf_put_reg32(dst_hi, rd[0], ctx); } static bool is_ldst_imm(s16 off, const u8 size) { s16 off_max = 0; switch (size) { case BPF_B: case BPF_W: off_max = 0xfff; break; case BPF_H: off_max = 0xff; break; case BPF_DW: /* Need to make sure off+4 does not overflow. */ off_max = 0xfff - 4; break; } return -off_max <= off && off <= off_max; } /* *(size *)(dst + off) = src */ static inline void emit_str_r(const s8 dst, const s8 src[], s16 off, struct jit_ctx *ctx, const u8 sz){ const s8 *tmp = bpf2a32[TMP_REG_1]; s8 rd; rd = arm_bpf_get_reg32(dst, tmp[1], ctx); if (!is_ldst_imm(off, sz)) { emit_a32_mov_i(tmp[0], off, ctx); emit(ARM_ADD_R(tmp[0], tmp[0], rd), ctx); rd = tmp[0]; off = 0; } switch (sz) { case BPF_B: /* Store a Byte */ emit(ARM_STRB_I(src_lo, rd, off), ctx); break; case BPF_H: /* Store a HalfWord */ emit(ARM_STRH_I(src_lo, rd, off), ctx); break; case BPF_W: /* Store a Word */ emit(ARM_STR_I(src_lo, rd, off), ctx); break; case BPF_DW: /* Store a Double Word */ emit(ARM_STR_I(src_lo, rd, off), ctx); emit(ARM_STR_I(src_hi, rd, off + 4), ctx); break; } } /* dst = *(size*)(src + off) */ static inline void emit_ldx_r(const s8 dst[], const s8 src, s16 off, struct jit_ctx *ctx, const u8 sz){ const s8 *tmp = bpf2a32[TMP_REG_1]; const s8 *rd = is_stacked(dst_lo) ? tmp : dst; s8 rm = src; if (!is_ldst_imm(off, sz)) { emit_a32_mov_i(tmp[0], off, ctx); emit(ARM_ADD_R(tmp[0], tmp[0], src), ctx); rm = tmp[0]; off = 0; } else if (rd[1] == rm) { emit(ARM_MOV_R(tmp[0], rm), ctx); rm = tmp[0]; } switch (sz) { case BPF_B: /* Load a Byte */ emit(ARM_LDRB_I(rd[1], rm, off), ctx); if (!ctx->prog->aux->verifier_zext) emit_a32_mov_i(rd[0], 0, ctx); break; case BPF_H: /* Load a HalfWord */ emit(ARM_LDRH_I(rd[1], rm, off), ctx); if (!ctx->prog->aux->verifier_zext) emit_a32_mov_i(rd[0], 0, ctx); break; case BPF_W: /* Load a Word */ emit(ARM_LDR_I(rd[1], rm, off), ctx); if (!ctx->prog->aux->verifier_zext) emit_a32_mov_i(rd[0], 0, ctx); break; case BPF_DW: /* Load a Double Word */ emit(ARM_LDR_I(rd[1], rm, off), ctx); emit(ARM_LDR_I(rd[0], rm, off + 4), ctx); break; } arm_bpf_put_reg64(dst, rd, ctx); } /* Arithmatic Operation */ static inline void emit_ar_r(const u8 rd, const u8 rt, const u8 rm, const u8 rn, struct jit_ctx *ctx, u8 op, bool is_jmp64) { switch (op) { case BPF_JSET: if (is_jmp64) { emit(ARM_AND_R(ARM_IP, rt, rn), ctx); emit(ARM_AND_R(ARM_LR, rd, rm), ctx); emit(ARM_ORRS_R(ARM_IP, ARM_LR, ARM_IP), ctx); } else { emit(ARM_ANDS_R(ARM_IP, rt, rn), ctx); } break; case BPF_JEQ: case BPF_JNE: case BPF_JGT: case BPF_JGE: case BPF_JLE: case BPF_JLT: if (is_jmp64) { emit(ARM_CMP_R(rd, rm), ctx); /* Only compare low halve if high halve are equal. */ _emit(ARM_COND_EQ, ARM_CMP_R(rt, rn), ctx); } else { emit(ARM_CMP_R(rt, rn), ctx); } break; case BPF_JSLE: case BPF_JSGT: emit(ARM_CMP_R(rn, rt), ctx); if (is_jmp64) emit(ARM_SBCS_R(ARM_IP, rm, rd), ctx); break; case BPF_JSLT: case BPF_JSGE: emit(ARM_CMP_R(rt, rn), ctx); if (is_jmp64) emit(ARM_SBCS_R(ARM_IP, rd, rm), ctx); break; } } static int out_offset = -1; /* initialized on the first pass of build_body() */ static int emit_bpf_tail_call(struct jit_ctx *ctx) { /* bpf_tail_call(void *prog_ctx, struct bpf_array *array, u64 index) */ const s8 *r2 = bpf2a32[BPF_REG_2]; const s8 *r3 = bpf2a32[BPF_REG_3]; const s8 *tmp = bpf2a32[TMP_REG_1]; const s8 *tmp2 = bpf2a32[TMP_REG_2]; const s8 *tcc = bpf2a32[TCALL_CNT]; const s8 *tc; const int idx0 = ctx->idx; #define cur_offset (ctx->idx - idx0) #define jmp_offset (out_offset - (cur_offset) - 2) u32 lo, hi; s8 r_array, r_index; int off; /* if (index >= array->map.max_entries) * goto out; */ BUILD_BUG_ON(offsetof(struct bpf_array, map.max_entries) > ARM_INST_LDST__IMM12); off = offsetof(struct bpf_array, map.max_entries); r_array = arm_bpf_get_reg32(r2[1], tmp2[0], ctx); /* index is 32-bit for arrays */ r_index = arm_bpf_get_reg32(r3[1], tmp2[1], ctx); /* array->map.max_entries */ emit(ARM_LDR_I(tmp[1], r_array, off), ctx); /* index >= array->map.max_entries */ emit(ARM_CMP_R(r_index, tmp[1]), ctx); _emit(ARM_COND_CS, ARM_B(jmp_offset), ctx); /* tmp2[0] = array, tmp2[1] = index */ /* if (tail_call_cnt > MAX_TAIL_CALL_CNT) * goto out; * tail_call_cnt++; */ lo = (u32)MAX_TAIL_CALL_CNT; hi = (u32)((u64)MAX_TAIL_CALL_CNT >> 32); tc = arm_bpf_get_reg64(tcc, tmp, ctx); emit(ARM_CMP_I(tc[0], hi), ctx); _emit(ARM_COND_EQ, ARM_CMP_I(tc[1], lo), ctx); _emit(ARM_COND_HI, ARM_B(jmp_offset), ctx); emit(ARM_ADDS_I(tc[1], tc[1], 1), ctx); emit(ARM_ADC_I(tc[0], tc[0], 0), ctx); arm_bpf_put_reg64(tcc, tmp, ctx); /* prog = array->ptrs[index] * if (prog == NULL) * goto out; */ BUILD_BUG_ON(imm8m(offsetof(struct bpf_array, ptrs)) < 0); off = imm8m(offsetof(struct bpf_array, ptrs)); emit(ARM_ADD_I(tmp[1], r_array, off), ctx); emit(ARM_LDR_R_SI(tmp[1], tmp[1], r_index, SRTYPE_ASL, 2), ctx); emit(ARM_CMP_I(tmp[1], 0), ctx); _emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx); /* goto *(prog->bpf_func + prologue_size); */ BUILD_BUG_ON(offsetof(struct bpf_prog, bpf_func) > ARM_INST_LDST__IMM12); off = offsetof(struct bpf_prog, bpf_func); emit(ARM_LDR_I(tmp[1], tmp[1], off), ctx); emit(ARM_ADD_I(tmp[1], tmp[1], ctx->prologue_bytes), ctx); emit_bx_r(tmp[1], ctx); /* out: */ if (out_offset == -1) out_offset = cur_offset; if (cur_offset != out_offset) { pr_err_once("tail_call out_offset = %d, expected %d!\n", cur_offset, out_offset); return -1; } return 0; #undef cur_offset #undef jmp_offset } /* 0xabcd => 0xcdab */ static inline void emit_rev16(const u8 rd, const u8 rn, struct jit_ctx *ctx) { #if __LINUX_ARM_ARCH__ < 6 const s8 *tmp2 = bpf2a32[TMP_REG_2]; emit(ARM_AND_I(tmp2[1], rn, 0xff), ctx); emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 8), ctx); emit(ARM_AND_I(tmp2[0], tmp2[0], 0xff), ctx); emit(ARM_ORR_SI(rd, tmp2[0], tmp2[1], SRTYPE_LSL, 8), ctx); #else /* ARMv6+ */ emit(ARM_REV16(rd, rn), ctx); #endif } /* 0xabcdefgh => 0xghefcdab */ static inline void emit_rev32(const u8 rd, const u8 rn, struct jit_ctx *ctx) { #if __LINUX_ARM_ARCH__ < 6 const s8 *tmp2 = bpf2a32[TMP_REG_2]; emit(ARM_AND_I(tmp2[1], rn, 0xff), ctx); emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 24), ctx); emit(ARM_ORR_SI(ARM_IP, tmp2[0], tmp2[1], SRTYPE_LSL, 24), ctx); emit(ARM_MOV_SI(tmp2[1], rn, SRTYPE_LSR, 8), ctx); emit(ARM_AND_I(tmp2[1], tmp2[1], 0xff), ctx); emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 16), ctx); emit(ARM_AND_I(tmp2[0], tmp2[0], 0xff), ctx); emit(ARM_MOV_SI(tmp2[0], tmp2[0], SRTYPE_LSL, 8), ctx); emit(ARM_ORR_SI(tmp2[0], tmp2[0], tmp2[1], SRTYPE_LSL, 16), ctx); emit(ARM_ORR_R(rd, ARM_IP, tmp2[0]), ctx); #else /* ARMv6+ */ emit(ARM_REV(rd, rn), ctx); #endif } // push the scratch stack register on top of the stack static inline void emit_push_r64(const s8 src[], struct jit_ctx *ctx) { const s8 *tmp2 = bpf2a32[TMP_REG_2]; const s8 *rt; u16 reg_set = 0; rt = arm_bpf_get_reg64(src, tmp2, ctx); reg_set = (1 << rt[1]) | (1 << rt[0]); emit(ARM_PUSH(reg_set), ctx); } static void build_prologue(struct jit_ctx *ctx) { const s8 arm_r0 = bpf2a32[BPF_REG_0][1]; const s8 *bpf_r1 = bpf2a32[BPF_REG_1]; const s8 *bpf_fp = bpf2a32[BPF_REG_FP]; const s8 *tcc = bpf2a32[TCALL_CNT]; /* Save callee saved registers. */ #ifdef CONFIG_FRAME_POINTER u16 reg_set = CALLEE_PUSH_MASK | 1 << ARM_IP | 1 << ARM_PC; emit(ARM_MOV_R(ARM_IP, ARM_SP), ctx); emit(ARM_PUSH(reg_set), ctx); emit(ARM_SUB_I(ARM_FP, ARM_IP, 4), ctx); #else emit(ARM_PUSH(CALLEE_PUSH_MASK), ctx); emit(ARM_MOV_R(ARM_FP, ARM_SP), ctx); #endif /* mov r3, #0 */ /* sub r2, sp, #SCRATCH_SIZE */ emit(ARM_MOV_I(bpf_r1[0], 0), ctx); emit(ARM_SUB_I(bpf_r1[1], ARM_SP, SCRATCH_SIZE), ctx); ctx->stack_size = imm8m(STACK_SIZE); /* Set up function call stack */ emit(ARM_SUB_I(ARM_SP, ARM_SP, ctx->stack_size), ctx); /* Set up BPF prog stack base register */ emit_a32_mov_r64(true, bpf_fp, bpf_r1, ctx); /* Initialize Tail Count */ emit(ARM_MOV_I(bpf_r1[1], 0), ctx); emit_a32_mov_r64(true, tcc, bpf_r1, ctx); /* Move BPF_CTX to BPF_R1 */ emit(ARM_MOV_R(bpf_r1[1], arm_r0), ctx); /* end of prologue */ } /* restore callee saved registers. */ static void build_epilogue(struct jit_ctx *ctx) { #ifdef CONFIG_FRAME_POINTER /* When using frame pointers, some additional registers need to * be loaded. */ u16 reg_set = CALLEE_POP_MASK | 1 << ARM_SP; emit(ARM_SUB_I(ARM_SP, ARM_FP, hweight16(reg_set) * 4), ctx); emit(ARM_LDM(ARM_SP, reg_set), ctx); #else /* Restore callee saved registers. */ emit(ARM_MOV_R(ARM_SP, ARM_FP), ctx); emit(ARM_POP(CALLEE_POP_MASK), ctx); #endif } /* * Convert an eBPF instruction to native instruction, i.e * JITs an eBPF instruction. * Returns : * 0 - Successfully JITed an 8-byte eBPF instruction * >0 - Successfully JITed a 16-byte eBPF instruction * <0 - Failed to JIT. */ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) { const u8 code = insn->code; const s8 *dst = bpf2a32[insn->dst_reg]; const s8 *src = bpf2a32[insn->src_reg]; const s8 *tmp = bpf2a32[TMP_REG_1]; const s8 *tmp2 = bpf2a32[TMP_REG_2]; const s16 off = insn->off; const s32 imm = insn->imm; const int i = insn - ctx->prog->insnsi; const bool is64 = BPF_CLASS(code) == BPF_ALU64; const s8 *rd, *rs; s8 rd_lo, rt, rm, rn; s32 jmp_offset; #define check_imm(bits, imm) do { \ if ((imm) >= (1 << ((bits) - 1)) || \ (imm) < -(1 << ((bits) - 1))) { \ pr_info("[%2d] imm=%d(0x%x) out of range\n", \ i, imm, imm); \ return -EINVAL; \ } \ } while (0) #define check_imm24(imm) check_imm(24, imm) switch (code) { /* ALU operations */ /* dst = src */ case BPF_ALU | BPF_MOV | BPF_K: case BPF_ALU | BPF_MOV | BPF_X: case BPF_ALU64 | BPF_MOV | BPF_K: case BPF_ALU64 | BPF_MOV | BPF_X: switch (BPF_SRC(code)) { case BPF_X: if (imm == 1) { /* Special mov32 for zext */ emit_a32_mov_i(dst_hi, 0, ctx); break; } emit_a32_mov_r64(is64, dst, src, ctx); break; case BPF_K: /* Sign-extend immediate value to destination reg */ emit_a32_mov_se_i64(is64, dst, imm, ctx); break; } break; /* dst = dst + src/imm */ /* dst = dst - src/imm */ /* dst = dst | src/imm */ /* dst = dst & src/imm */ /* dst = dst ^ src/imm */ /* dst = dst * src/imm */ /* dst = dst << src */ /* dst = dst >> src */ case BPF_ALU | BPF_ADD | BPF_K: case BPF_ALU | BPF_ADD | BPF_X: case BPF_ALU | BPF_SUB | BPF_K: case BPF_ALU | BPF_SUB | BPF_X: case BPF_ALU | BPF_OR | BPF_K: case BPF_ALU | BPF_OR | BPF_X: case BPF_ALU | BPF_AND | BPF_K: case BPF_ALU | BPF_AND | BPF_X: case BPF_ALU | BPF_XOR | BPF_K: case BPF_ALU | BPF_XOR | BPF_X: case BPF_ALU | BPF_MUL | BPF_K: case BPF_ALU | BPF_MUL | BPF_X: case BPF_ALU | BPF_LSH | BPF_X: case BPF_ALU | BPF_RSH | BPF_X: case BPF_ALU | BPF_ARSH | BPF_X: case BPF_ALU64 | BPF_ADD | BPF_K: case BPF_ALU64 | BPF_ADD | BPF_X: case BPF_ALU64 | BPF_SUB | BPF_K: case BPF_ALU64 | BPF_SUB | BPF_X: case BPF_ALU64 | BPF_OR | BPF_K: case BPF_ALU64 | BPF_OR | BPF_X: case BPF_ALU64 | BPF_AND | BPF_K: case BPF_ALU64 | BPF_AND | BPF_X: case BPF_ALU64 | BPF_XOR | BPF_K: case BPF_ALU64 | BPF_XOR | BPF_X: switch (BPF_SRC(code)) { case BPF_X: emit_a32_alu_r64(is64, dst, src, ctx, BPF_OP(code)); break; case BPF_K: /* Move immediate value to the temporary register * and then do the ALU operation on the temporary * register as this will sign-extend the immediate * value into temporary reg and then it would be * safe to do the operation on it. */ emit_a32_mov_se_i64(is64, tmp2, imm, ctx); emit_a32_alu_r64(is64, dst, tmp2, ctx, BPF_OP(code)); break; } break; /* dst = dst / src(imm) */ /* dst = dst % src(imm) */ case BPF_ALU | BPF_DIV | BPF_K: case BPF_ALU | BPF_DIV | BPF_X: case BPF_ALU | BPF_MOD | BPF_K: case BPF_ALU | BPF_MOD | BPF_X: rd_lo = arm_bpf_get_reg32(dst_lo, tmp2[1], ctx); switch (BPF_SRC(code)) { case BPF_X: rt = arm_bpf_get_reg32(src_lo, tmp2[0], ctx); break; case BPF_K: rt = tmp2[0]; emit_a32_mov_i(rt, imm, ctx); break; default: rt = src_lo; break; } emit_udivmod(rd_lo, rd_lo, rt, ctx, BPF_OP(code)); arm_bpf_put_reg32(dst_lo, rd_lo, ctx); if (!ctx->prog->aux->verifier_zext) emit_a32_mov_i(dst_hi, 0, ctx); break; case BPF_ALU64 | BPF_DIV | BPF_K: case BPF_ALU64 | BPF_DIV | BPF_X: case BPF_ALU64 | BPF_MOD | BPF_K: case BPF_ALU64 | BPF_MOD | BPF_X: goto notyet; /* dst = dst << imm */ /* dst = dst >> imm */ /* dst = dst >> imm (signed) */ case BPF_ALU | BPF_LSH | BPF_K: case BPF_ALU | BPF_RSH | BPF_K: case BPF_ALU | BPF_ARSH | BPF_K: if (unlikely(imm > 31)) return -EINVAL; if (imm) emit_a32_alu_i(dst_lo, imm, ctx, BPF_OP(code)); if (!ctx->prog->aux->verifier_zext) emit_a32_mov_i(dst_hi, 0, ctx); break; /* dst = dst << imm */ case BPF_ALU64 | BPF_LSH | BPF_K: if (unlikely(imm > 63)) return -EINVAL; emit_a32_lsh_i64(dst, imm, ctx); break; /* dst = dst >> imm */ case BPF_ALU64 | BPF_RSH | BPF_K: if (unlikely(imm > 63)) return -EINVAL; emit_a32_rsh_i64(dst, imm, ctx); break; /* dst = dst << src */ case BPF_ALU64 | BPF_LSH | BPF_X: emit_a32_lsh_r64(dst, src, ctx); break; /* dst = dst >> src */ case BPF_ALU64 | BPF_RSH | BPF_X: emit_a32_rsh_r64(dst, src, ctx); break; /* dst = dst >> src (signed) */ case BPF_ALU64 | BPF_ARSH | BPF_X: emit_a32_arsh_r64(dst, src, ctx); break; /* dst = dst >> imm (signed) */ case BPF_ALU64 | BPF_ARSH | BPF_K: if (unlikely(imm > 63)) return -EINVAL; emit_a32_arsh_i64(dst, imm, ctx); break; /* dst = ~dst */ case BPF_ALU | BPF_NEG: emit_a32_alu_i(dst_lo, 0, ctx, BPF_OP(code)); if (!ctx->prog->aux->verifier_zext) emit_a32_mov_i(dst_hi, 0, ctx); break; /* dst = ~dst (64 bit) */ case BPF_ALU64 | BPF_NEG: emit_a32_neg64(dst, ctx); break; /* dst = dst * src/imm */ case BPF_ALU64 | BPF_MUL | BPF_X: case BPF_ALU64 | BPF_MUL | BPF_K: switch (BPF_SRC(code)) { case BPF_X: emit_a32_mul_r64(dst, src, ctx); break; case BPF_K: /* Move immediate value to the temporary register * and then do the multiplication on it as this * will sign-extend the immediate value into temp * reg then it would be safe to do the operation * on it. */ emit_a32_mov_se_i64(is64, tmp2, imm, ctx); emit_a32_mul_r64(dst, tmp2, ctx); break; } break; /* dst = htole(dst) */ /* dst = htobe(dst) */ case BPF_ALU | BPF_END | BPF_FROM_LE: case BPF_ALU | BPF_END | BPF_FROM_BE: rd = arm_bpf_get_reg64(dst, tmp, ctx); if (BPF_SRC(code) == BPF_FROM_LE) goto emit_bswap_uxt; switch (imm) { case 16: emit_rev16(rd[1], rd[1], ctx); goto emit_bswap_uxt; case 32: emit_rev32(rd[1], rd[1], ctx); goto emit_bswap_uxt; case 64: emit_rev32(ARM_LR, rd[1], ctx); emit_rev32(rd[1], rd[0], ctx); emit(ARM_MOV_R(rd[0], ARM_LR), ctx); break; } goto exit; emit_bswap_uxt: switch (imm) { case 16: /* zero-extend 16 bits into 64 bits */ #if __LINUX_ARM_ARCH__ < 6 emit_a32_mov_i(tmp2[1], 0xffff, ctx); emit(ARM_AND_R(rd[1], rd[1], tmp2[1]), ctx); #else /* ARMv6+ */ emit(ARM_UXTH(rd[1], rd[1]), ctx); #endif if (!ctx->prog->aux->verifier_zext) emit(ARM_EOR_R(rd[0], rd[0], rd[0]), ctx); break; case 32: /* zero-extend 32 bits into 64 bits */ if (!ctx->prog->aux->verifier_zext) emit(ARM_EOR_R(rd[0], rd[0], rd[0]), ctx); break; case 64: /* nop */ break; } exit: arm_bpf_put_reg64(dst, rd, ctx); break; /* dst = imm64 */ case BPF_LD | BPF_IMM | BPF_DW: { u64 val = (u32)imm | (u64)insn[1].imm << 32; emit_a32_mov_i64(dst, val, ctx); return 1; } /* LDX: dst = *(size *)(src + off) */ case BPF_LDX | BPF_MEM | BPF_W: case BPF_LDX | BPF_MEM | BPF_H: case BPF_LDX | BPF_MEM | BPF_B: case BPF_LDX | BPF_MEM | BPF_DW: rn = arm_bpf_get_reg32(src_lo, tmp2[1], ctx); emit_ldx_r(dst, rn, off, ctx, BPF_SIZE(code)); break; /* speculation barrier */ case BPF_ST | BPF_NOSPEC: break; /* ST: *(size *)(dst + off) = imm */ case BPF_ST | BPF_MEM | BPF_W: case BPF_ST | BPF_MEM | BPF_H: case BPF_ST | BPF_MEM | BPF_B: case BPF_ST | BPF_MEM | BPF_DW: switch (BPF_SIZE(code)) { case BPF_DW: /* Sign-extend immediate value into temp reg */ emit_a32_mov_se_i64(true, tmp2, imm, ctx); break; case BPF_W: case BPF_H: case BPF_B: emit_a32_mov_i(tmp2[1], imm, ctx); break; } emit_str_r(dst_lo, tmp2, off, ctx, BPF_SIZE(code)); break; /* STX XADD: lock *(u32 *)(dst + off) += src */ case BPF_STX | BPF_XADD | BPF_W: /* STX XADD: lock *(u64 *)(dst + off) += src */ case BPF_STX | BPF_XADD | BPF_DW: goto notyet; /* STX: *(size *)(dst + off) = src */ case BPF_STX | BPF_MEM | BPF_W: case BPF_STX | BPF_MEM | BPF_H: case BPF_STX | BPF_MEM | BPF_B: case BPF_STX | BPF_MEM | BPF_DW: rs = arm_bpf_get_reg64(src, tmp2, ctx); emit_str_r(dst_lo, rs, off, ctx, BPF_SIZE(code)); break; /* PC += off if dst == src */ /* PC += off if dst > src */ /* PC += off if dst >= src */ /* PC += off if dst < src */ /* PC += off if dst <= src */ /* PC += off if dst != src */ /* PC += off if dst > src (signed) */ /* PC += off if dst >= src (signed) */ /* PC += off if dst < src (signed) */ /* PC += off if dst <= src (signed) */ /* PC += off if dst & src */ case BPF_JMP | BPF_JEQ | BPF_X: case BPF_JMP | BPF_JGT | BPF_X: case BPF_JMP | BPF_JGE | BPF_X: case BPF_JMP | BPF_JNE | BPF_X: case BPF_JMP | BPF_JSGT | BPF_X: case BPF_JMP | BPF_JSGE | BPF_X: case BPF_JMP | BPF_JSET | BPF_X: case BPF_JMP | BPF_JLE | BPF_X: case BPF_JMP | BPF_JLT | BPF_X: case BPF_JMP | BPF_JSLT | BPF_X: case BPF_JMP | BPF_JSLE | BPF_X: case BPF_JMP32 | BPF_JEQ | BPF_X: case BPF_JMP32 | BPF_JGT | BPF_X: case BPF_JMP32 | BPF_JGE | BPF_X: case BPF_JMP32 | BPF_JNE | BPF_X: case BPF_JMP32 | BPF_JSGT | BPF_X: case BPF_JMP32 | BPF_JSGE | BPF_X: case BPF_JMP32 | BPF_JSET | BPF_X: case BPF_JMP32 | BPF_JLE | BPF_X: case BPF_JMP32 | BPF_JLT | BPF_X: case BPF_JMP32 | BPF_JSLT | BPF_X: case BPF_JMP32 | BPF_JSLE | BPF_X: /* Setup source registers */ rm = arm_bpf_get_reg32(src_hi, tmp2[0], ctx); rn = arm_bpf_get_reg32(src_lo, tmp2[1], ctx); goto go_jmp; /* PC += off if dst == imm */ /* PC += off if dst > imm */ /* PC += off if dst >= imm */ /* PC += off if dst < imm */ /* PC += off if dst <= imm */ /* PC += off if dst != imm */ /* PC += off if dst > imm (signed) */ /* PC += off if dst >= imm (signed) */ /* PC += off if dst < imm (signed) */ /* PC += off if dst <= imm (signed) */ /* PC += off if dst & imm */ case BPF_JMP | BPF_JEQ | BPF_K: case BPF_JMP | BPF_JGT | BPF_K: case BPF_JMP | BPF_JGE | BPF_K: case BPF_JMP | BPF_JNE | BPF_K: case BPF_JMP | BPF_JSGT | BPF_K: case BPF_JMP | BPF_JSGE | BPF_K: case BPF_JMP | BPF_JSET | BPF_K: case BPF_JMP | BPF_JLT | BPF_K: case BPF_JMP | BPF_JLE | BPF_K: case BPF_JMP | BPF_JSLT | BPF_K: case BPF_JMP | BPF_JSLE | BPF_K: case BPF_JMP32 | BPF_JEQ | BPF_K: case BPF_JMP32 | BPF_JGT | BPF_K: case BPF_JMP32 | BPF_JGE | BPF_K: case BPF_JMP32 | BPF_JNE | BPF_K: case BPF_JMP32 | BPF_JSGT | BPF_K: case BPF_JMP32 | BPF_JSGE | BPF_K: case BPF_JMP32 | BPF_JSET | BPF_K: case BPF_JMP32 | BPF_JLT | BPF_K: case BPF_JMP32 | BPF_JLE | BPF_K: case BPF_JMP32 | BPF_JSLT | BPF_K: case BPF_JMP32 | BPF_JSLE | BPF_K: if (off == 0) break; rm = tmp2[0]; rn = tmp2[1]; /* Sign-extend immediate value */ emit_a32_mov_se_i64(true, tmp2, imm, ctx); go_jmp: /* Setup destination register */ rd = arm_bpf_get_reg64(dst, tmp, ctx); /* Check for the condition */ emit_ar_r(rd[0], rd[1], rm, rn, ctx, BPF_OP(code), BPF_CLASS(code) == BPF_JMP); /* Setup JUMP instruction */ jmp_offset = bpf2a32_offset(i+off, i, ctx); switch (BPF_OP(code)) { case BPF_JNE: case BPF_JSET: _emit(ARM_COND_NE, ARM_B(jmp_offset), ctx); break; case BPF_JEQ: _emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx); break; case BPF_JGT: _emit(ARM_COND_HI, ARM_B(jmp_offset), ctx); break; case BPF_JGE: _emit(ARM_COND_CS, ARM_B(jmp_offset), ctx); break; case BPF_JSGT: _emit(ARM_COND_LT, ARM_B(jmp_offset), ctx); break; case BPF_JSGE: _emit(ARM_COND_GE, ARM_B(jmp_offset), ctx); break; case BPF_JLE: _emit(ARM_COND_LS, ARM_B(jmp_offset), ctx); break; case BPF_JLT: _emit(ARM_COND_CC, ARM_B(jmp_offset), ctx); break; case BPF_JSLT: _emit(ARM_COND_LT, ARM_B(jmp_offset), ctx); break; case BPF_JSLE: _emit(ARM_COND_GE, ARM_B(jmp_offset), ctx); break; } break; /* JMP OFF */ case BPF_JMP | BPF_JA: { if (off == 0) break; jmp_offset = bpf2a32_offset(i+off, i, ctx); check_imm24(jmp_offset); emit(ARM_B(jmp_offset), ctx); break; } /* tail call */ case BPF_JMP | BPF_TAIL_CALL: if (emit_bpf_tail_call(ctx)) return -EFAULT; break; /* function call */ case BPF_JMP | BPF_CALL: { const s8 *r0 = bpf2a32[BPF_REG_0]; const s8 *r1 = bpf2a32[BPF_REG_1]; const s8 *r2 = bpf2a32[BPF_REG_2]; const s8 *r3 = bpf2a32[BPF_REG_3]; const s8 *r4 = bpf2a32[BPF_REG_4]; const s8 *r5 = bpf2a32[BPF_REG_5]; const u32 func = (u32)__bpf_call_base + (u32)imm; emit_a32_mov_r64(true, r0, r1, ctx); emit_a32_mov_r64(true, r1, r2, ctx); emit_push_r64(r5, ctx); emit_push_r64(r4, ctx); emit_push_r64(r3, ctx); emit_a32_mov_i(tmp[1], func, ctx); emit_blx_r(tmp[1], ctx); emit(ARM_ADD_I(ARM_SP, ARM_SP, imm8m(24)), ctx); // callee clean break; } /* function return */ case BPF_JMP | BPF_EXIT: /* Optimization: when last instruction is EXIT * simply fallthrough to epilogue. */ if (i == ctx->prog->len - 1) break; jmp_offset = epilogue_offset(ctx); check_imm24(jmp_offset); emit(ARM_B(jmp_offset), ctx); break; notyet: pr_info_once("*** NOT YET: opcode %02x ***\n", code); return -EFAULT; default: pr_err_once("unknown opcode %02x\n", code); return -EINVAL; } if (ctx->flags & FLAG_IMM_OVERFLOW) /* * this instruction generated an overflow when * trying to access the literal pool, so * delegate this filter to the kernel interpreter. */ return -1; return 0; } static int build_body(struct jit_ctx *ctx) { const struct bpf_prog *prog = ctx->prog; unsigned int i; for (i = 0; i < prog->len; i++) { const struct bpf_insn *insn = &(prog->insnsi[i]); int ret; ret = build_insn(insn, ctx); /* It's used with loading the 64 bit immediate value. */ if (ret > 0) { i++; if (ctx->target == NULL) ctx->offsets[i] = ctx->idx; continue; } if (ctx->target == NULL) ctx->offsets[i] = ctx->idx; /* If unsuccesfull, return with error code */ if (ret) return ret; } return 0; } static int validate_code(struct jit_ctx *ctx) { int i; for (i = 0; i < ctx->idx; i++) { if (ctx->target[i] == __opcode_to_mem_arm(ARM_INST_UDF)) return -1; } return 0; } void bpf_jit_compile(struct bpf_prog *prog) { /* Nothing to do here. We support Internal BPF. */ } bool bpf_jit_needs_zext(void) { return true; } struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) { struct bpf_prog *tmp, *orig_prog = prog; struct bpf_binary_header *header; bool tmp_blinded = false; struct jit_ctx ctx; unsigned int tmp_idx; unsigned int image_size; u8 *image_ptr; /* If BPF JIT was not enabled then we must fall back to * the interpreter. */ if (!prog->jit_requested) return orig_prog; /* If constant blinding was enabled and we failed during blinding * then we must fall back to the interpreter. Otherwise, we save * the new JITed code. */ tmp = bpf_jit_blind_constants(prog); if (IS_ERR(tmp)) return orig_prog; if (tmp != prog) { tmp_blinded = true; prog = tmp; } memset(&ctx, 0, sizeof(ctx)); ctx.prog = prog; ctx.cpu_architecture = cpu_architecture(); /* Not able to allocate memory for offsets[] , then * we must fall back to the interpreter */ ctx.offsets = kcalloc(prog->len, sizeof(int), GFP_KERNEL); if (ctx.offsets == NULL) { prog = orig_prog; goto out; } /* 1) fake pass to find in the length of the JITed code, * to compute ctx->offsets and other context variables * needed to compute final JITed code. * Also, calculate random starting pointer/start of JITed code * which is prefixed by random number of fault instructions. * * If the first pass fails then there is no chance of it * being successful in the second pass, so just fall back * to the interpreter. */ if (build_body(&ctx)) { prog = orig_prog; goto out_off; } tmp_idx = ctx.idx; build_prologue(&ctx); ctx.prologue_bytes = (ctx.idx - tmp_idx) * 4; ctx.epilogue_offset = ctx.idx; #if __LINUX_ARM_ARCH__ < 7 tmp_idx = ctx.idx; build_epilogue(&ctx); ctx.epilogue_bytes = (ctx.idx - tmp_idx) * 4; ctx.idx += ctx.imm_count; if (ctx.imm_count) { ctx.imms = kcalloc(ctx.imm_count, sizeof(u32), GFP_KERNEL); if (ctx.imms == NULL) { prog = orig_prog; goto out_off; } } #else /* there's nothing about the epilogue on ARMv7 */ build_epilogue(&ctx); #endif /* Now we can get the actual image size of the JITed arm code. * Currently, we are not considering the THUMB-2 instructions * for jit, although it can decrease the size of the image. * * As each arm instruction is of length 32bit, we are translating * number of JITed intructions into the size required to store these * JITed code. */ image_size = sizeof(u32) * ctx.idx; /* Now we know the size of the structure to make */ header = bpf_jit_binary_alloc(image_size, &image_ptr, sizeof(u32), jit_fill_hole); /* Not able to allocate memory for the structure then * we must fall back to the interpretation */ if (header == NULL) { prog = orig_prog; goto out_imms; } /* 2.) Actual pass to generate final JIT code */ ctx.target = (u32 *) image_ptr; ctx.idx = 0; build_prologue(&ctx); /* If building the body of the JITed code fails somehow, * we fall back to the interpretation. */ if (build_body(&ctx) < 0) { image_ptr = NULL; bpf_jit_binary_free(header); prog = orig_prog; goto out_imms; } build_epilogue(&ctx); /* 3.) Extra pass to validate JITed Code */ if (validate_code(&ctx)) { image_ptr = NULL; bpf_jit_binary_free(header); prog = orig_prog; goto out_imms; } flush_icache_range((u32)header, (u32)(ctx.target + ctx.idx)); if (bpf_jit_enable > 1) /* there are 2 passes here */ bpf_jit_dump(prog->len, image_size, 2, ctx.target); bpf_jit_binary_lock_ro(header); prog->bpf_func = (void *)ctx.target; prog->jited = 1; prog->jited_len = image_size; out_imms: #if __LINUX_ARM_ARCH__ < 7 if (ctx.imm_count) kfree(ctx.imms); #endif out_off: kfree(ctx.offsets); out: if (tmp_blinded) bpf_jit_prog_release_other(prog, prog == orig_prog ? tmp : orig_prog); return prog; }