static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx) { int i; if (ctx->seen & (SEEN_MEM | SEEN_DATAREF)) { PPC_ADDI(1, 1, BPF_PPC_STACKFRAME); if (ctx->seen & SEEN_DATAREF) { PPC_LD(0, 1, 16); PPC_MTLR(0); PPC_LD(r_D, 1, -(8*(32-r_D))); PPC_LD(r_HL, 1, -(8*(32-r_HL))); } if (ctx->seen & SEEN_MEM) { /* Restore any saved non-vol registers */ for (i = r_M; i < (r_M+16); i++) { if (ctx->seen & (1 << (i-r_M))) PPC_LD(i, 1, -(8*(32-i))); } } } /* The RETs have left a return value in R3. */ PPC_BLR(); }
/* Assemble the body code between the prologue & epilogue */ static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *ctx, u32 *addrs, bool extra_pass) { const struct bpf_insn *insn = fp->insnsi; int flen = fp->len; int i, ret; /* Start of epilogue code - will only be valid 2nd pass onwards */ u32 exit_addr = addrs[flen]; for (i = 0; i < flen; i++) { u32 code = insn[i].code; u32 dst_reg = b2p[insn[i].dst_reg]; u32 src_reg = b2p[insn[i].src_reg]; s16 off = insn[i].off; s32 imm = insn[i].imm; bool func_addr_fixed; u64 func_addr; u64 imm64; u32 true_cond; u32 tmp_idx; /* * addrs[] maps a BPF bytecode address into a real offset from * the start of the body code. */ addrs[i] = ctx->idx * 4; /* * As an optimization, we note down which non-volatile registers * are used so that we can only save/restore those in our * prologue and epilogue. We do this here regardless of whether * the actual BPF instruction uses src/dst registers or not * (for instance, BPF_CALL does not use them). The expectation * is that those instructions will have src_reg/dst_reg set to * 0. Even otherwise, we just lose some prologue/epilogue * optimization but everything else should work without * any issues. */ if (dst_reg >= BPF_PPC_NVR_MIN && dst_reg < 32) bpf_set_seen_register(ctx, insn[i].dst_reg); if (src_reg >= BPF_PPC_NVR_MIN && src_reg < 32) bpf_set_seen_register(ctx, insn[i].src_reg); switch (code) { /* * Arithmetic operations: ADD/SUB/MUL/DIV/MOD/NEG */ case BPF_ALU | BPF_ADD | BPF_X: /* (u32) dst += (u32) src */ case BPF_ALU64 | BPF_ADD | BPF_X: /* dst += src */ PPC_ADD(dst_reg, dst_reg, src_reg); goto bpf_alu32_trunc; case BPF_ALU | BPF_SUB | BPF_X: /* (u32) dst -= (u32) src */ case BPF_ALU64 | BPF_SUB | BPF_X: /* dst -= src */ PPC_SUB(dst_reg, dst_reg, src_reg); goto bpf_alu32_trunc; case BPF_ALU | BPF_ADD | BPF_K: /* (u32) dst += (u32) imm */ case BPF_ALU | BPF_SUB | BPF_K: /* (u32) dst -= (u32) imm */ case BPF_ALU64 | BPF_ADD | BPF_K: /* dst += imm */ case BPF_ALU64 | BPF_SUB | BPF_K: /* dst -= imm */ if (BPF_OP(code) == BPF_SUB) imm = -imm; if (imm) { if (imm >= -32768 && imm < 32768) PPC_ADDI(dst_reg, dst_reg, IMM_L(imm)); else { PPC_LI32(b2p[TMP_REG_1], imm); PPC_ADD(dst_reg, dst_reg, b2p[TMP_REG_1]); } } goto bpf_alu32_trunc; case BPF_ALU | BPF_MUL | BPF_X: /* (u32) dst *= (u32) src */ case BPF_ALU64 | BPF_MUL | BPF_X: /* dst *= src */ if (BPF_CLASS(code) == BPF_ALU) PPC_MULW(dst_reg, dst_reg, src_reg); else PPC_MULD(dst_reg, dst_reg, src_reg); goto bpf_alu32_trunc; case BPF_ALU | BPF_MUL | BPF_K: /* (u32) dst *= (u32) imm */ case BPF_ALU64 | BPF_MUL | BPF_K: /* dst *= imm */ if (imm >= -32768 && imm < 32768) PPC_MULI(dst_reg, dst_reg, IMM_L(imm)); else { PPC_LI32(b2p[TMP_REG_1], imm); if (BPF_CLASS(code) == BPF_ALU) PPC_MULW(dst_reg, dst_reg, b2p[TMP_REG_1]); else PPC_MULD(dst_reg, dst_reg, b2p[TMP_REG_1]); } goto bpf_alu32_trunc; case BPF_ALU | BPF_DIV | BPF_X: /* (u32) dst /= (u32) src */ case BPF_ALU | BPF_MOD | BPF_X: /* (u32) dst %= (u32) src */ if (BPF_OP(code) == BPF_MOD) { PPC_DIVWU(b2p[TMP_REG_1], dst_reg, src_reg); PPC_MULW(b2p[TMP_REG_1], src_reg, b2p[TMP_REG_1]); PPC_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]); } else PPC_DIVWU(dst_reg, dst_reg, src_reg); goto bpf_alu32_trunc; case BPF_ALU64 | BPF_DIV | BPF_X: /* dst /= src */ case BPF_ALU64 | BPF_MOD | BPF_X: /* dst %= src */ if (BPF_OP(code) == BPF_MOD) { PPC_DIVD(b2p[TMP_REG_1], dst_reg, src_reg); PPC_MULD(b2p[TMP_REG_1], src_reg, b2p[TMP_REG_1]); PPC_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]); } else PPC_DIVD(dst_reg, dst_reg, src_reg); break; case BPF_ALU | BPF_MOD | BPF_K: /* (u32) dst %= (u32) imm */ case BPF_ALU | BPF_DIV | BPF_K: /* (u32) dst /= (u32) imm */ case BPF_ALU64 | BPF_MOD | BPF_K: /* dst %= imm */ case BPF_ALU64 | BPF_DIV | BPF_K: /* dst /= imm */ if (imm == 0) return -EINVAL; else if (imm == 1) goto bpf_alu32_trunc; PPC_LI32(b2p[TMP_REG_1], imm); switch (BPF_CLASS(code)) { case BPF_ALU: if (BPF_OP(code) == BPF_MOD) { PPC_DIVWU(b2p[TMP_REG_2], dst_reg, b2p[TMP_REG_1]); PPC_MULW(b2p[TMP_REG_1], b2p[TMP_REG_1], b2p[TMP_REG_2]); PPC_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]); } else PPC_DIVWU(dst_reg, dst_reg, b2p[TMP_REG_1]); break; case BPF_ALU64: if (BPF_OP(code) == BPF_MOD) { PPC_DIVD(b2p[TMP_REG_2], dst_reg, b2p[TMP_REG_1]); PPC_MULD(b2p[TMP_REG_1], b2p[TMP_REG_1], b2p[TMP_REG_2]); PPC_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]); } else PPC_DIVD(dst_reg, dst_reg, b2p[TMP_REG_1]); break; } goto bpf_alu32_trunc; case BPF_ALU | BPF_NEG: /* (u32) dst = -dst */ case BPF_ALU64 | BPF_NEG: /* dst = -dst */ PPC_NEG(dst_reg, dst_reg); goto bpf_alu32_trunc; /* * Logical operations: AND/OR/XOR/[A]LSH/[A]RSH */ case BPF_ALU | BPF_AND | BPF_X: /* (u32) dst = dst & src */ case BPF_ALU64 | BPF_AND | BPF_X: /* dst = dst & src */ PPC_AND(dst_reg, dst_reg, src_reg); goto bpf_alu32_trunc; case BPF_ALU | BPF_AND | BPF_K: /* (u32) dst = dst & imm */ case BPF_ALU64 | BPF_AND | BPF_K: /* dst = dst & imm */ if (!IMM_H(imm)) PPC_ANDI(dst_reg, dst_reg, IMM_L(imm)); else { /* Sign-extended */ PPC_LI32(b2p[TMP_REG_1], imm); PPC_AND(dst_reg, dst_reg, b2p[TMP_REG_1]); } goto bpf_alu32_trunc; case BPF_ALU | BPF_OR | BPF_X: /* dst = (u32) dst | (u32) src */ case BPF_ALU64 | BPF_OR | BPF_X: /* dst = dst | src */ PPC_OR(dst_reg, dst_reg, src_reg); goto bpf_alu32_trunc; case BPF_ALU | BPF_OR | BPF_K:/* dst = (u32) dst | (u32) imm */ case BPF_ALU64 | BPF_OR | BPF_K:/* dst = dst | imm */ if (imm < 0 && BPF_CLASS(code) == BPF_ALU64) { /* Sign-extended */ PPC_LI32(b2p[TMP_REG_1], imm); PPC_OR(dst_reg, dst_reg, b2p[TMP_REG_1]); } else { if (IMM_L(imm)) PPC_ORI(dst_reg, dst_reg, IMM_L(imm)); if (IMM_H(imm)) PPC_ORIS(dst_reg, dst_reg, IMM_H(imm)); } goto bpf_alu32_trunc; case BPF_ALU | BPF_XOR | BPF_X: /* (u32) dst ^= src */ case BPF_ALU64 | BPF_XOR | BPF_X: /* dst ^= src */ PPC_XOR(dst_reg, dst_reg, src_reg); goto bpf_alu32_trunc; case BPF_ALU | BPF_XOR | BPF_K: /* (u32) dst ^= (u32) imm */ case BPF_ALU64 | BPF_XOR | BPF_K: /* dst ^= imm */ if (imm < 0 && BPF_CLASS(code) == BPF_ALU64) { /* Sign-extended */ PPC_LI32(b2p[TMP_REG_1], imm); PPC_XOR(dst_reg, dst_reg, b2p[TMP_REG_1]); } else { if (IMM_L(imm)) PPC_XORI(dst_reg, dst_reg, IMM_L(imm)); if (IMM_H(imm)) PPC_XORIS(dst_reg, dst_reg, IMM_H(imm)); } goto bpf_alu32_trunc; case BPF_ALU | BPF_LSH | BPF_X: /* (u32) dst <<= (u32) src */ /* slw clears top 32 bits */ PPC_SLW(dst_reg, dst_reg, src_reg); break; case BPF_ALU64 | BPF_LSH | BPF_X: /* dst <<= src; */ PPC_SLD(dst_reg, dst_reg, src_reg); break; case BPF_ALU | BPF_LSH | BPF_K: /* (u32) dst <<== (u32) imm */ /* with imm 0, we still need to clear top 32 bits */ PPC_SLWI(dst_reg, dst_reg, imm); break; case BPF_ALU64 | BPF_LSH | BPF_K: /* dst <<== imm */ if (imm != 0) PPC_SLDI(dst_reg, dst_reg, imm); break; case BPF_ALU | BPF_RSH | BPF_X: /* (u32) dst >>= (u32) src */ PPC_SRW(dst_reg, dst_reg, src_reg); break; case BPF_ALU64 | BPF_RSH | BPF_X: /* dst >>= src */ PPC_SRD(dst_reg, dst_reg, src_reg); break; case BPF_ALU | BPF_RSH | BPF_K: /* (u32) dst >>= (u32) imm */ PPC_SRWI(dst_reg, dst_reg, imm); break; case BPF_ALU64 | BPF_RSH | BPF_K: /* dst >>= imm */ if (imm != 0) PPC_SRDI(dst_reg, dst_reg, imm); break; case BPF_ALU | BPF_ARSH | BPF_X: /* (s32) dst >>= src */ PPC_SRAW(dst_reg, dst_reg, src_reg); goto bpf_alu32_trunc; case BPF_ALU64 | BPF_ARSH | BPF_X: /* (s64) dst >>= src */ PPC_SRAD(dst_reg, dst_reg, src_reg); break; case BPF_ALU | BPF_ARSH | BPF_K: /* (s32) dst >>= imm */ PPC_SRAWI(dst_reg, dst_reg, imm); goto bpf_alu32_trunc; case BPF_ALU64 | BPF_ARSH | BPF_K: /* (s64) dst >>= imm */ if (imm != 0) PPC_SRADI(dst_reg, dst_reg, imm); break; /* * MOV */ case BPF_ALU | BPF_MOV | BPF_X: /* (u32) dst = src */ case BPF_ALU64 | BPF_MOV | BPF_X: /* dst = src */ PPC_MR(dst_reg, src_reg); goto bpf_alu32_trunc; case BPF_ALU | BPF_MOV | BPF_K: /* (u32) dst = imm */ case BPF_ALU64 | BPF_MOV | BPF_K: /* dst = (s64) imm */ PPC_LI32(dst_reg, imm); if (imm < 0) goto bpf_alu32_trunc; break; bpf_alu32_trunc: /* Truncate to 32-bits */ if (BPF_CLASS(code) == BPF_ALU) PPC_RLWINM(dst_reg, dst_reg, 0, 0, 31); break; /* * BPF_FROM_BE/LE */ case BPF_ALU | BPF_END | BPF_FROM_LE: case BPF_ALU | BPF_END | BPF_FROM_BE: #ifdef __BIG_ENDIAN__ if (BPF_SRC(code) == BPF_FROM_BE) goto emit_clear; #else /* !__BIG_ENDIAN__ */ if (BPF_SRC(code) == BPF_FROM_LE) goto emit_clear; #endif switch (imm) { case 16: /* Rotate 8 bits left & mask with 0x0000ff00 */ PPC_RLWINM(b2p[TMP_REG_1], dst_reg, 8, 16, 23); /* Rotate 8 bits right & insert LSB to reg */ PPC_RLWIMI(b2p[TMP_REG_1], dst_reg, 24, 24, 31); /* Move result back to dst_reg */ PPC_MR(dst_reg, b2p[TMP_REG_1]); break; case 32: /* * Rotate word left by 8 bits: * 2 bytes are already in their final position * -- byte 2 and 4 (of bytes 1, 2, 3 and 4) */ PPC_RLWINM(b2p[TMP_REG_1], dst_reg, 8, 0, 31); /* Rotate 24 bits and insert byte 1 */ PPC_RLWIMI(b2p[TMP_REG_1], dst_reg, 24, 0, 7); /* Rotate 24 bits and insert byte 3 */ PPC_RLWIMI(b2p[TMP_REG_1], dst_reg, 24, 16, 23); PPC_MR(dst_reg, b2p[TMP_REG_1]); break; case 64: /* * Way easier and faster(?) to store the value * into stack and then use ldbrx * * ctx->seen will be reliable in pass2, but * the instructions generated will remain the * same across all passes */ PPC_STD(dst_reg, 1, bpf_jit_stack_local(ctx)); PPC_ADDI(b2p[TMP_REG_1], 1, bpf_jit_stack_local(ctx)); PPC_LDBRX(dst_reg, 0, b2p[TMP_REG_1]); break; } break; emit_clear: switch (imm) { case 16: /* zero-extend 16 bits into 64 bits */ PPC_RLDICL(dst_reg, dst_reg, 0, 48); break; case 32: /* zero-extend 32 bits into 64 bits */ PPC_RLDICL(dst_reg, dst_reg, 0, 32); break; case 64: /* nop */ break; } break; /* * BPF_ST(X) */ case BPF_STX | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = src */ case BPF_ST | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = imm */ if (BPF_CLASS(code) == BPF_ST) { PPC_LI(b2p[TMP_REG_1], imm); src_reg = b2p[TMP_REG_1]; } PPC_STB(src_reg, dst_reg, off); break; case BPF_STX | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = src */ case BPF_ST | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = imm */ if (BPF_CLASS(code) == BPF_ST) { PPC_LI(b2p[TMP_REG_1], imm); src_reg = b2p[TMP_REG_1]; } PPC_STH(src_reg, dst_reg, off); break; case BPF_STX | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = src */ case BPF_ST | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = imm */ if (BPF_CLASS(code) == BPF_ST) { PPC_LI32(b2p[TMP_REG_1], imm); src_reg = b2p[TMP_REG_1]; } PPC_STW(src_reg, dst_reg, off); break; case BPF_STX | BPF_MEM | BPF_DW: /* (u64 *)(dst + off) = src */ case BPF_ST | BPF_MEM | BPF_DW: /* *(u64 *)(dst + off) = imm */ if (BPF_CLASS(code) == BPF_ST) { PPC_LI32(b2p[TMP_REG_1], imm); src_reg = b2p[TMP_REG_1]; } PPC_STD(src_reg, dst_reg, off); break; /* * BPF_STX XADD (atomic_add) */ /* *(u32 *)(dst + off) += src */ case BPF_STX | BPF_XADD | BPF_W: /* Get EA into TMP_REG_1 */ PPC_ADDI(b2p[TMP_REG_1], dst_reg, off); tmp_idx = ctx->idx * 4; /* load value from memory into TMP_REG_2 */ PPC_BPF_LWARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0); /* add value from src_reg into this */ PPC_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg); /* store result back */ PPC_BPF_STWCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]); /* we're done if this succeeded */ PPC_BCC_SHORT(COND_NE, tmp_idx); break; /* *(u64 *)(dst + off) += src */ case BPF_STX | BPF_XADD | BPF_DW: PPC_ADDI(b2p[TMP_REG_1], dst_reg, off); tmp_idx = ctx->idx * 4; PPC_BPF_LDARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0); PPC_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg); PPC_BPF_STDCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]); PPC_BCC_SHORT(COND_NE, tmp_idx); break; /* * BPF_LDX */ /* dst = *(u8 *)(ul) (src + off) */ case BPF_LDX | BPF_MEM | BPF_B: PPC_LBZ(dst_reg, src_reg, off); break; /* dst = *(u16 *)(ul) (src + off) */ case BPF_LDX | BPF_MEM | BPF_H: PPC_LHZ(dst_reg, src_reg, off); break; /* dst = *(u32 *)(ul) (src + off) */ case BPF_LDX | BPF_MEM | BPF_W: PPC_LWZ(dst_reg, src_reg, off); break; /* dst = *(u64 *)(ul) (src + off) */ case BPF_LDX | BPF_MEM | BPF_DW: PPC_LD(dst_reg, src_reg, off); break; /* * Doubleword load * 16 byte instruction that uses two 'struct bpf_insn' */ case BPF_LD | BPF_IMM | BPF_DW: /* dst = (u64) imm */ imm64 = ((u64)(u32) insn[i].imm) | (((u64)(u32) insn[i+1].imm) << 32); /* Adjust for two bpf instructions */ addrs[++i] = ctx->idx * 4; PPC_LI64(dst_reg, imm64); break; /* * Return/Exit */ case BPF_JMP | BPF_EXIT: /* * If this isn't the very last instruction, branch to * the epilogue. If we _are_ the last instruction, * we'll just fall through to the epilogue. */ if (i != flen - 1) PPC_JMP(exit_addr); /* else fall through to the epilogue */ break; /* * Call kernel helper or bpf function */ case BPF_JMP | BPF_CALL: ctx->seen |= SEEN_FUNC; ret = bpf_jit_get_func_addr(fp, &insn[i], extra_pass, &func_addr, &func_addr_fixed); if (ret < 0) return ret; if (func_addr_fixed) bpf_jit_emit_func_call_hlp(image, ctx, func_addr); else bpf_jit_emit_func_call_rel(image, ctx, func_addr); /* move return value from r3 to BPF_REG_0 */ PPC_MR(b2p[BPF_REG_0], 3); break; /* * Jumps and branches */ case BPF_JMP | BPF_JA: PPC_JMP(addrs[i + 1 + off]); break; case BPF_JMP | BPF_JGT | BPF_K: case BPF_JMP | BPF_JGT | BPF_X: case BPF_JMP | BPF_JSGT | BPF_K: case BPF_JMP | BPF_JSGT | BPF_X: true_cond = COND_GT; goto cond_branch; case BPF_JMP | BPF_JLT | BPF_K: case BPF_JMP | BPF_JLT | BPF_X: case BPF_JMP | BPF_JSLT | BPF_K: case BPF_JMP | BPF_JSLT | BPF_X: true_cond = COND_LT; goto cond_branch; case BPF_JMP | BPF_JGE | BPF_K: case BPF_JMP | BPF_JGE | BPF_X: case BPF_JMP | BPF_JSGE | BPF_K: case BPF_JMP | BPF_JSGE | BPF_X: true_cond = COND_GE; goto cond_branch; case BPF_JMP | BPF_JLE | BPF_K: case BPF_JMP | BPF_JLE | BPF_X: case BPF_JMP | BPF_JSLE | BPF_K: case BPF_JMP | BPF_JSLE | BPF_X: true_cond = COND_LE; goto cond_branch; case BPF_JMP | BPF_JEQ | BPF_K: case BPF_JMP | BPF_JEQ | BPF_X: true_cond = COND_EQ; goto cond_branch; case BPF_JMP | BPF_JNE | BPF_K: case BPF_JMP | BPF_JNE | BPF_X: true_cond = COND_NE; goto cond_branch; case BPF_JMP | BPF_JSET | BPF_K: case BPF_JMP | BPF_JSET | BPF_X: true_cond = COND_NE; /* Fall through */ cond_branch: switch (code) { case BPF_JMP | BPF_JGT | BPF_X: case BPF_JMP | BPF_JLT | BPF_X: case BPF_JMP | BPF_JGE | BPF_X: case BPF_JMP | BPF_JLE | BPF_X: case BPF_JMP | BPF_JEQ | BPF_X: case BPF_JMP | BPF_JNE | BPF_X: /* unsigned comparison */ PPC_CMPLD(dst_reg, src_reg); break; case BPF_JMP | BPF_JSGT | BPF_X: case BPF_JMP | BPF_JSLT | BPF_X: case BPF_JMP | BPF_JSGE | BPF_X: case BPF_JMP | BPF_JSLE | BPF_X: /* signed comparison */ PPC_CMPD(dst_reg, src_reg); break; case BPF_JMP | BPF_JSET | BPF_X: PPC_AND_DOT(b2p[TMP_REG_1], dst_reg, src_reg); break; case BPF_JMP | BPF_JNE | BPF_K: case BPF_JMP | BPF_JEQ | BPF_K: case BPF_JMP | BPF_JGT | BPF_K: case BPF_JMP | BPF_JLT | BPF_K: case BPF_JMP | BPF_JGE | BPF_K: case BPF_JMP | BPF_JLE | BPF_K: /* * Need sign-extended load, so only positive * values can be used as imm in cmpldi */ if (imm >= 0 && imm < 32768) PPC_CMPLDI(dst_reg, imm); else { /* sign-extending load */ PPC_LI32(b2p[TMP_REG_1], imm); /* ... but unsigned comparison */ PPC_CMPLD(dst_reg, b2p[TMP_REG_1]); } break; case BPF_JMP | BPF_JSGT | BPF_K: case BPF_JMP | BPF_JSLT | BPF_K: case BPF_JMP | BPF_JSGE | BPF_K: case BPF_JMP | BPF_JSLE | BPF_K: /* * signed comparison, so any 16-bit value * can be used in cmpdi */ if (imm >= -32768 && imm < 32768) PPC_CMPDI(dst_reg, imm); else { PPC_LI32(b2p[TMP_REG_1], imm); PPC_CMPD(dst_reg, b2p[TMP_REG_1]); } break; case BPF_JMP | BPF_JSET | BPF_K: /* andi does not sign-extend the immediate */ if (imm >= 0 && imm < 32768) /* PPC_ANDI is _only/always_ dot-form */ PPC_ANDI(b2p[TMP_REG_1], dst_reg, imm); else { PPC_LI32(b2p[TMP_REG_1], imm); PPC_AND_DOT(b2p[TMP_REG_1], dst_reg, b2p[TMP_REG_1]); } break; } PPC_BCC(true_cond, addrs[i + 1 + off]); break; /* * Tail call */ case BPF_JMP | BPF_TAIL_CALL: ctx->seen |= SEEN_TAILCALL; bpf_jit_emit_tail_call(image, ctx, addrs[i + 1]); break; default: /* * The filter contains something cruel & unusual. * We don't handle it, but also there shouldn't be * anything missing from our list. */ pr_err_ratelimited("eBPF filter opcode %04x (@%d) unsupported\n", code, i); return -ENOTSUPP; } } /* Set end-of-body-code address for exit. */ addrs[i] = ctx->idx * 4; return 0; }
static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out) { /* * By now, the eBPF program has already setup parameters in r3, r4 and r5 * r3/BPF_REG_1 - pointer to ctx -- passed as is to the next bpf program * r4/BPF_REG_2 - pointer to bpf_array * r5/BPF_REG_3 - index in bpf_array */ int b2p_bpf_array = b2p[BPF_REG_2]; int b2p_index = b2p[BPF_REG_3]; /* * if (index >= array->map.max_entries) * goto out; */ PPC_LWZ(b2p[TMP_REG_1], b2p_bpf_array, offsetof(struct bpf_array, map.max_entries)); PPC_RLWINM(b2p_index, b2p_index, 0, 0, 31); PPC_CMPLW(b2p_index, b2p[TMP_REG_1]); PPC_BCC(COND_GE, out); /* * if (tail_call_cnt > MAX_TAIL_CALL_CNT) * goto out; */ PPC_LD(b2p[TMP_REG_1], 1, bpf_jit_stack_tailcallcnt(ctx)); PPC_CMPLWI(b2p[TMP_REG_1], MAX_TAIL_CALL_CNT); PPC_BCC(COND_GT, out); /* * tail_call_cnt++; */ PPC_ADDI(b2p[TMP_REG_1], b2p[TMP_REG_1], 1); PPC_BPF_STL(b2p[TMP_REG_1], 1, bpf_jit_stack_tailcallcnt(ctx)); /* prog = array->ptrs[index]; */ PPC_MULI(b2p[TMP_REG_1], b2p_index, 8); PPC_ADD(b2p[TMP_REG_1], b2p[TMP_REG_1], b2p_bpf_array); PPC_LD(b2p[TMP_REG_1], b2p[TMP_REG_1], offsetof(struct bpf_array, ptrs)); /* * if (prog == NULL) * goto out; */ PPC_CMPLDI(b2p[TMP_REG_1], 0); PPC_BCC(COND_EQ, out); /* goto *(prog->bpf_func + prologue_size); */ PPC_LD(b2p[TMP_REG_1], b2p[TMP_REG_1], offsetof(struct bpf_prog, bpf_func)); #ifdef PPC64_ELF_ABI_v1 /* skip past the function descriptor */ PPC_ADDI(b2p[TMP_REG_1], b2p[TMP_REG_1], FUNCTION_DESCR_SIZE + BPF_TAILCALL_PROLOGUE_SIZE); #else PPC_ADDI(b2p[TMP_REG_1], b2p[TMP_REG_1], BPF_TAILCALL_PROLOGUE_SIZE); #endif PPC_MTCTR(b2p[TMP_REG_1]); /* tear down stack, restore NVRs, ... */ bpf_jit_emit_common_epilogue(image, ctx); PPC_BCTR(); /* out: */ }