| /* |
| * BPF JIT compiler for ARM64 |
| * |
| * Copyright (C) 2014-2016 Zi Shen Lim <zlim.lnx@gmail.com> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| #define pr_fmt(fmt) "bpf_jit: " fmt |
| |
| #include <linux/bpf.h> |
| #include <linux/filter.h> |
| #include <linux/printk.h> |
| #include <linux/slab.h> |
| |
| #include <asm/byteorder.h> |
| #include <asm/cacheflush.h> |
| #include <asm/debug-monitors.h> |
| #include <asm/set_memory.h> |
| |
| #include "bpf_jit.h" |
| |
| #define TMP_REG_1 (MAX_BPF_JIT_REG + 0) |
| #define TMP_REG_2 (MAX_BPF_JIT_REG + 1) |
| #define TCALL_CNT (MAX_BPF_JIT_REG + 2) |
| #define TMP_REG_3 (MAX_BPF_JIT_REG + 3) |
| |
| /* Map BPF registers to A64 registers */ |
| static const int bpf2a64[] = { |
| /* return value from in-kernel function, and exit value from eBPF */ |
| [BPF_REG_0] = A64_R(7), |
| /* arguments from eBPF program to in-kernel function */ |
| [BPF_REG_1] = A64_R(0), |
| [BPF_REG_2] = A64_R(1), |
| [BPF_REG_3] = A64_R(2), |
| [BPF_REG_4] = A64_R(3), |
| [BPF_REG_5] = A64_R(4), |
| /* callee saved registers that in-kernel function will preserve */ |
| [BPF_REG_6] = A64_R(19), |
| [BPF_REG_7] = A64_R(20), |
| [BPF_REG_8] = A64_R(21), |
| [BPF_REG_9] = A64_R(22), |
| /* read-only frame pointer to access stack */ |
| [BPF_REG_FP] = A64_R(25), |
| /* temporary registers for internal BPF JIT */ |
| [TMP_REG_1] = A64_R(10), |
| [TMP_REG_2] = A64_R(11), |
| [TMP_REG_3] = A64_R(12), |
| /* tail_call_cnt */ |
| [TCALL_CNT] = A64_R(26), |
| /* temporary register for blinding constants */ |
| [BPF_REG_AX] = A64_R(9), |
| }; |
| |
| struct jit_ctx { |
| const struct bpf_prog *prog; |
| int idx; |
| int epilogue_offset; |
| int *offset; |
| __le32 *image; |
| u32 stack_size; |
| }; |
| |
| static inline void emit(const u32 insn, struct jit_ctx *ctx) |
| { |
| if (ctx->image != NULL) |
| ctx->image[ctx->idx] = cpu_to_le32(insn); |
| |
| ctx->idx++; |
| } |
| |
| static inline void emit_a64_mov_i(const int is64, const int reg, |
| const s32 val, struct jit_ctx *ctx) |
| { |
| u16 hi = val >> 16; |
| u16 lo = val & 0xffff; |
| |
| if (hi & 0x8000) { |
| if (hi == 0xffff) { |
| emit(A64_MOVN(is64, reg, (u16)~lo, 0), ctx); |
| } else { |
| emit(A64_MOVN(is64, reg, (u16)~hi, 16), ctx); |
| if (lo != 0xffff) |
| emit(A64_MOVK(is64, reg, lo, 0), ctx); |
| } |
| } else { |
| emit(A64_MOVZ(is64, reg, lo, 0), ctx); |
| if (hi) |
| emit(A64_MOVK(is64, reg, hi, 16), ctx); |
| } |
| } |
| |
| static int i64_i16_blocks(const u64 val, bool inverse) |
| { |
| return (((val >> 0) & 0xffff) != (inverse ? 0xffff : 0x0000)) + |
| (((val >> 16) & 0xffff) != (inverse ? 0xffff : 0x0000)) + |
| (((val >> 32) & 0xffff) != (inverse ? 0xffff : 0x0000)) + |
| (((val >> 48) & 0xffff) != (inverse ? 0xffff : 0x0000)); |
| } |
| |
| static inline void emit_a64_mov_i64(const int reg, const u64 val, |
| struct jit_ctx *ctx) |
| { |
| u64 nrm_tmp = val, rev_tmp = ~val; |
| bool inverse; |
| int shift; |
| |
| if (!(nrm_tmp >> 32)) |
| return emit_a64_mov_i(0, reg, (u32)val, ctx); |
| |
| inverse = i64_i16_blocks(nrm_tmp, true) < i64_i16_blocks(nrm_tmp, false); |
| shift = max(round_down((inverse ? (fls64(rev_tmp) - 1) : |
| (fls64(nrm_tmp) - 1)), 16), 0); |
| if (inverse) |
| emit(A64_MOVN(1, reg, (rev_tmp >> shift) & 0xffff, shift), ctx); |
| else |
| emit(A64_MOVZ(1, reg, (nrm_tmp >> shift) & 0xffff, shift), ctx); |
| shift -= 16; |
| while (shift >= 0) { |
| if (((nrm_tmp >> shift) & 0xffff) != (inverse ? 0xffff : 0x0000)) |
| emit(A64_MOVK(1, reg, (nrm_tmp >> shift) & 0xffff, shift), ctx); |
| shift -= 16; |
| } |
| } |
| |
| /* |
| * Kernel addresses in the vmalloc space use at most 48 bits, and the |
| * remaining bits are guaranteed to be 0x1. So we can compose the address |
| * with a fixed length movn/movk/movk sequence. |
| */ |
| static inline void emit_addr_mov_i64(const int reg, const u64 val, |
| struct jit_ctx *ctx) |
| { |
| u64 tmp = val; |
| int shift = 0; |
| |
| emit(A64_MOVN(1, reg, ~tmp & 0xffff, shift), ctx); |
| while (shift < 32) { |
| tmp >>= 16; |
| shift += 16; |
| emit(A64_MOVK(1, reg, tmp & 0xffff, shift), ctx); |
| } |
| } |
| |
| static inline int bpf2a64_offset(int bpf_to, int bpf_from, |
| const struct jit_ctx *ctx) |
| { |
| int to = ctx->offset[bpf_to]; |
| /* -1 to account for the Branch instruction */ |
| int from = ctx->offset[bpf_from] - 1; |
| |
| return to - from; |
| } |
| |
| static void jit_fill_hole(void *area, unsigned int size) |
| { |
| __le32 *ptr; |
| /* We are guaranteed to have aligned memory. */ |
| for (ptr = area; size >= sizeof(u32); size -= sizeof(u32)) |
| *ptr++ = cpu_to_le32(AARCH64_BREAK_FAULT); |
| } |
| |
| static inline int epilogue_offset(const struct jit_ctx *ctx) |
| { |
| int to = ctx->epilogue_offset; |
| int from = ctx->idx; |
| |
| return to - from; |
| } |
| |
| /* Stack must be multiples of 16B */ |
| #define STACK_ALIGN(sz) (((sz) + 15) & ~15) |
| |
| /* Tail call offset to jump into */ |
| #define PROLOGUE_OFFSET 7 |
| |
| static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf) |
| { |
| const struct bpf_prog *prog = ctx->prog; |
| const u8 r6 = bpf2a64[BPF_REG_6]; |
| const u8 r7 = bpf2a64[BPF_REG_7]; |
| const u8 r8 = bpf2a64[BPF_REG_8]; |
| const u8 r9 = bpf2a64[BPF_REG_9]; |
| const u8 fp = bpf2a64[BPF_REG_FP]; |
| const u8 tcc = bpf2a64[TCALL_CNT]; |
| const int idx0 = ctx->idx; |
| int cur_offset; |
| |
| /* |
| * BPF prog stack layout |
| * |
| * high |
| * original A64_SP => 0:+-----+ BPF prologue |
| * |FP/LR| |
| * current A64_FP => -16:+-----+ |
| * | ... | callee saved registers |
| * BPF fp register => -64:+-----+ <= (BPF_FP) |
| * | | |
| * | ... | BPF prog stack |
| * | | |
| * +-----+ <= (BPF_FP - prog->aux->stack_depth) |
| * |RSVD | padding |
| * current A64_SP => +-----+ <= (BPF_FP - ctx->stack_size) |
| * | | |
| * | ... | Function call stack |
| * | | |
| * +-----+ |
| * low |
| * |
| */ |
| |
| /* Save FP and LR registers to stay align with ARM64 AAPCS */ |
| emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx); |
| emit(A64_MOV(1, A64_FP, A64_SP), ctx); |
| |
| /* Save callee-saved registers */ |
| emit(A64_PUSH(r6, r7, A64_SP), ctx); |
| emit(A64_PUSH(r8, r9, A64_SP), ctx); |
| emit(A64_PUSH(fp, tcc, A64_SP), ctx); |
| |
| /* Set up BPF prog stack base register */ |
| emit(A64_MOV(1, fp, A64_SP), ctx); |
| |
| if (!ebpf_from_cbpf) { |
| /* Initialize tail_call_cnt */ |
| emit(A64_MOVZ(1, tcc, 0, 0), ctx); |
| |
| cur_offset = ctx->idx - idx0; |
| if (cur_offset != PROLOGUE_OFFSET) { |
| pr_err_once("PROLOGUE_OFFSET = %d, expected %d!\n", |
| cur_offset, PROLOGUE_OFFSET); |
| return -1; |
| } |
| } |
| |
| ctx->stack_size = STACK_ALIGN(prog->aux->stack_depth); |
| |
| /* Set up function call stack */ |
| emit(A64_SUB_I(1, A64_SP, A64_SP, ctx->stack_size), ctx); |
| return 0; |
| } |
| |
| 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 u8 r2 = bpf2a64[BPF_REG_2]; |
| const u8 r3 = bpf2a64[BPF_REG_3]; |
| |
| const u8 tmp = bpf2a64[TMP_REG_1]; |
| const u8 prg = bpf2a64[TMP_REG_2]; |
| const u8 tcc = bpf2a64[TCALL_CNT]; |
| const int idx0 = ctx->idx; |
| #define cur_offset (ctx->idx - idx0) |
| #define jmp_offset (out_offset - (cur_offset)) |
| size_t off; |
| |
| /* if (index >= array->map.max_entries) |
| * goto out; |
| */ |
| off = offsetof(struct bpf_array, map.max_entries); |
| emit_a64_mov_i64(tmp, off, ctx); |
| emit(A64_LDR32(tmp, r2, tmp), ctx); |
| emit(A64_MOV(0, r3, r3), ctx); |
| emit(A64_CMP(0, r3, tmp), ctx); |
| emit(A64_B_(A64_COND_CS, jmp_offset), ctx); |
| |
| /* if (tail_call_cnt > MAX_TAIL_CALL_CNT) |
| * goto out; |
| * tail_call_cnt++; |
| */ |
| emit_a64_mov_i64(tmp, MAX_TAIL_CALL_CNT, ctx); |
| emit(A64_CMP(1, tcc, tmp), ctx); |
| emit(A64_B_(A64_COND_HI, jmp_offset), ctx); |
| emit(A64_ADD_I(1, tcc, tcc, 1), ctx); |
| |
| /* prog = array->ptrs[index]; |
| * if (prog == NULL) |
| * goto out; |
| */ |
| off = offsetof(struct bpf_array, ptrs); |
| emit_a64_mov_i64(tmp, off, ctx); |
| emit(A64_ADD(1, tmp, r2, tmp), ctx); |
| emit(A64_LSL(1, prg, r3, 3), ctx); |
| emit(A64_LDR64(prg, tmp, prg), ctx); |
| emit(A64_CBZ(1, prg, jmp_offset), ctx); |
| |
| /* goto *(prog->bpf_func + prologue_offset); */ |
| off = offsetof(struct bpf_prog, bpf_func); |
| emit_a64_mov_i64(tmp, off, ctx); |
| emit(A64_LDR64(tmp, prg, tmp), ctx); |
| emit(A64_ADD_I(1, tmp, tmp, sizeof(u32) * PROLOGUE_OFFSET), ctx); |
| emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx); |
| emit(A64_BR(tmp), 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 |
| } |
| |
| static void build_epilogue(struct jit_ctx *ctx) |
| { |
| const u8 r0 = bpf2a64[BPF_REG_0]; |
| const u8 r6 = bpf2a64[BPF_REG_6]; |
| const u8 r7 = bpf2a64[BPF_REG_7]; |
| const u8 r8 = bpf2a64[BPF_REG_8]; |
| const u8 r9 = bpf2a64[BPF_REG_9]; |
| const u8 fp = bpf2a64[BPF_REG_FP]; |
| |
| /* We're done with BPF stack */ |
| emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx); |
| |
| /* Restore fs (x25) and x26 */ |
| emit(A64_POP(fp, A64_R(26), A64_SP), ctx); |
| |
| /* Restore callee-saved register */ |
| emit(A64_POP(r8, r9, A64_SP), ctx); |
| emit(A64_POP(r6, r7, A64_SP), ctx); |
| |
| /* Restore FP/LR registers */ |
| emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx); |
| |
| /* Set return value */ |
| emit(A64_MOV(1, A64_R(0), r0), ctx); |
| |
| emit(A64_RET(A64_LR), ctx); |
| } |
| |
| /* 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, |
| bool extra_pass) |
| { |
| const u8 code = insn->code; |
| const u8 dst = bpf2a64[insn->dst_reg]; |
| const u8 src = bpf2a64[insn->src_reg]; |
| const u8 tmp = bpf2a64[TMP_REG_1]; |
| const u8 tmp2 = bpf2a64[TMP_REG_2]; |
| const u8 tmp3 = bpf2a64[TMP_REG_3]; |
| 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 bool isdw = BPF_SIZE(code) == BPF_DW; |
| u8 jmp_cond; |
| s32 jmp_offset; |
| |
| #define check_imm(bits, imm) do { \ |
| if ((((imm) > 0) && ((imm) >> (bits))) || \ |
| (((imm) < 0) && (~(imm) >> (bits)))) { \ |
| pr_info("[%2d] imm=%d(0x%x) out of range\n", \ |
| i, imm, imm); \ |
| return -EINVAL; \ |
| } \ |
| } while (0) |
| #define check_imm19(imm) check_imm(19, imm) |
| #define check_imm26(imm) check_imm(26, imm) |
| |
| switch (code) { |
| /* dst = src */ |
| case BPF_ALU | BPF_MOV | BPF_X: |
| case BPF_ALU64 | BPF_MOV | BPF_X: |
| emit(A64_MOV(is64, dst, src), ctx); |
| break; |
| /* dst = dst OP src */ |
| case BPF_ALU | BPF_ADD | BPF_X: |
| case BPF_ALU64 | BPF_ADD | BPF_X: |
| emit(A64_ADD(is64, dst, dst, src), ctx); |
| break; |
| case BPF_ALU | BPF_SUB | BPF_X: |
| case BPF_ALU64 | BPF_SUB | BPF_X: |
| emit(A64_SUB(is64, dst, dst, src), ctx); |
| break; |
| case BPF_ALU | BPF_AND | BPF_X: |
| case BPF_ALU64 | BPF_AND | BPF_X: |
| emit(A64_AND(is64, dst, dst, src), ctx); |
| break; |
| case BPF_ALU | BPF_OR | BPF_X: |
| case BPF_ALU64 | BPF_OR | BPF_X: |
| emit(A64_ORR(is64, dst, dst, src), ctx); |
| break; |
| case BPF_ALU | BPF_XOR | BPF_X: |
| case BPF_ALU64 | BPF_XOR | BPF_X: |
| emit(A64_EOR(is64, dst, dst, src), ctx); |
| break; |
| case BPF_ALU | BPF_MUL | BPF_X: |
| case BPF_ALU64 | BPF_MUL | BPF_X: |
| emit(A64_MUL(is64, dst, dst, src), ctx); |
| break; |
| case BPF_ALU | BPF_DIV | BPF_X: |
| case BPF_ALU64 | BPF_DIV | BPF_X: |
| case BPF_ALU | BPF_MOD | BPF_X: |
| case BPF_ALU64 | BPF_MOD | BPF_X: |
| switch (BPF_OP(code)) { |
| case BPF_DIV: |
| emit(A64_UDIV(is64, dst, dst, src), ctx); |
| break; |
| case BPF_MOD: |
| emit(A64_UDIV(is64, tmp, dst, src), ctx); |
| emit(A64_MUL(is64, tmp, tmp, src), ctx); |
| emit(A64_SUB(is64, dst, dst, tmp), ctx); |
| break; |
| } |
| break; |
| case BPF_ALU | BPF_LSH | BPF_X: |
| case BPF_ALU64 | BPF_LSH | BPF_X: |
| emit(A64_LSLV(is64, dst, dst, src), ctx); |
| break; |
| case BPF_ALU | BPF_RSH | BPF_X: |
| case BPF_ALU64 | BPF_RSH | BPF_X: |
| emit(A64_LSRV(is64, dst, dst, src), ctx); |
| break; |
| case BPF_ALU | BPF_ARSH | BPF_X: |
| case BPF_ALU64 | BPF_ARSH | BPF_X: |
| emit(A64_ASRV(is64, dst, dst, src), ctx); |
| break; |
| /* dst = -dst */ |
| case BPF_ALU | BPF_NEG: |
| case BPF_ALU64 | BPF_NEG: |
| emit(A64_NEG(is64, dst, dst), ctx); |
| break; |
| /* dst = BSWAP##imm(dst) */ |
| case BPF_ALU | BPF_END | BPF_FROM_LE: |
| case BPF_ALU | BPF_END | BPF_FROM_BE: |
| #ifdef CONFIG_CPU_BIG_ENDIAN |
| if (BPF_SRC(code) == BPF_FROM_BE) |
| goto emit_bswap_uxt; |
| #else /* !CONFIG_CPU_BIG_ENDIAN */ |
| if (BPF_SRC(code) == BPF_FROM_LE) |
| goto emit_bswap_uxt; |
| #endif |
| switch (imm) { |
| case 16: |
| emit(A64_REV16(is64, dst, dst), ctx); |
| /* zero-extend 16 bits into 64 bits */ |
| emit(A64_UXTH(is64, dst, dst), ctx); |
| break; |
| case 32: |
| emit(A64_REV32(is64, dst, dst), ctx); |
| /* upper 32 bits already cleared */ |
| break; |
| case 64: |
| emit(A64_REV64(dst, dst), ctx); |
| break; |
| } |
| break; |
| emit_bswap_uxt: |
| switch (imm) { |
| case 16: |
| /* zero-extend 16 bits into 64 bits */ |
| emit(A64_UXTH(is64, dst, dst), ctx); |
| break; |
| case 32: |
| /* zero-extend 32 bits into 64 bits */ |
| emit(A64_UXTW(is64, dst, dst), ctx); |
| break; |
| case 64: |
| /* nop */ |
| break; |
| } |
| break; |
| /* dst = imm */ |
| case BPF_ALU | BPF_MOV | BPF_K: |
| case BPF_ALU64 | BPF_MOV | BPF_K: |
| emit_a64_mov_i(is64, dst, imm, ctx); |
| break; |
| /* dst = dst OP imm */ |
| case BPF_ALU | BPF_ADD | BPF_K: |
| case BPF_ALU64 | BPF_ADD | BPF_K: |
| emit_a64_mov_i(is64, tmp, imm, ctx); |
| emit(A64_ADD(is64, dst, dst, tmp), ctx); |
| break; |
| case BPF_ALU | BPF_SUB | BPF_K: |
| case BPF_ALU64 | BPF_SUB | BPF_K: |
| emit_a64_mov_i(is64, tmp, imm, ctx); |
| emit(A64_SUB(is64, dst, dst, tmp), ctx); |
| break; |
| case BPF_ALU | BPF_AND | BPF_K: |
| case BPF_ALU64 | BPF_AND | BPF_K: |
| emit_a64_mov_i(is64, tmp, imm, ctx); |
| emit(A64_AND(is64, dst, dst, tmp), ctx); |
| break; |
| case BPF_ALU | BPF_OR | BPF_K: |
| case BPF_ALU64 | BPF_OR | BPF_K: |
| emit_a64_mov_i(is64, tmp, imm, ctx); |
| emit(A64_ORR(is64, dst, dst, tmp), ctx); |
| break; |
| case BPF_ALU | BPF_XOR | BPF_K: |
| case BPF_ALU64 | BPF_XOR | BPF_K: |
| emit_a64_mov_i(is64, tmp, imm, ctx); |
| emit(A64_EOR(is64, dst, dst, tmp), ctx); |
| break; |
| case BPF_ALU | BPF_MUL | BPF_K: |
| case BPF_ALU64 | BPF_MUL | BPF_K: |
| emit_a64_mov_i(is64, tmp, imm, ctx); |
| emit(A64_MUL(is64, dst, dst, tmp), ctx); |
| break; |
| case BPF_ALU | BPF_DIV | BPF_K: |
| case BPF_ALU64 | BPF_DIV | BPF_K: |
| emit_a64_mov_i(is64, tmp, imm, ctx); |
| emit(A64_UDIV(is64, dst, dst, tmp), ctx); |
| break; |
| case BPF_ALU | BPF_MOD | BPF_K: |
| case BPF_ALU64 | BPF_MOD | BPF_K: |
| emit_a64_mov_i(is64, tmp2, imm, ctx); |
| emit(A64_UDIV(is64, tmp, dst, tmp2), ctx); |
| emit(A64_MUL(is64, tmp, tmp, tmp2), ctx); |
| emit(A64_SUB(is64, dst, dst, tmp), ctx); |
| break; |
| case BPF_ALU | BPF_LSH | BPF_K: |
| case BPF_ALU64 | BPF_LSH | BPF_K: |
| emit(A64_LSL(is64, dst, dst, imm), ctx); |
| break; |
| case BPF_ALU | BPF_RSH | BPF_K: |
| case BPF_ALU64 | BPF_RSH | BPF_K: |
| emit(A64_LSR(is64, dst, dst, imm), ctx); |
| break; |
| case BPF_ALU | BPF_ARSH | BPF_K: |
| case BPF_ALU64 | BPF_ARSH | BPF_K: |
| emit(A64_ASR(is64, dst, dst, imm), ctx); |
| break; |
| |
| /* JUMP off */ |
| case BPF_JMP | BPF_JA: |
| jmp_offset = bpf2a64_offset(i + off, i, ctx); |
| check_imm26(jmp_offset); |
| emit(A64_B(jmp_offset), ctx); |
| break; |
| /* IF (dst COND src) JUMP off */ |
| case BPF_JMP | BPF_JEQ | BPF_X: |
| 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_JNE | BPF_X: |
| 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: |
| emit(A64_CMP(1, dst, src), ctx); |
| emit_cond_jmp: |
| jmp_offset = bpf2a64_offset(i + off, i, ctx); |
| check_imm19(jmp_offset); |
| switch (BPF_OP(code)) { |
| case BPF_JEQ: |
| jmp_cond = A64_COND_EQ; |
| break; |
| case BPF_JGT: |
| jmp_cond = A64_COND_HI; |
| break; |
| case BPF_JLT: |
| jmp_cond = A64_COND_CC; |
| break; |
| case BPF_JGE: |
| jmp_cond = A64_COND_CS; |
| break; |
| case BPF_JLE: |
| jmp_cond = A64_COND_LS; |
| break; |
| case BPF_JSET: |
| case BPF_JNE: |
| jmp_cond = A64_COND_NE; |
| break; |
| case BPF_JSGT: |
| jmp_cond = A64_COND_GT; |
| break; |
| case BPF_JSLT: |
| jmp_cond = A64_COND_LT; |
| break; |
| case BPF_JSGE: |
| jmp_cond = A64_COND_GE; |
| break; |
| case BPF_JSLE: |
| jmp_cond = A64_COND_LE; |
| break; |
| default: |
| return -EFAULT; |
| } |
| emit(A64_B_(jmp_cond, jmp_offset), ctx); |
| break; |
| case BPF_JMP | BPF_JSET | BPF_X: |
| emit(A64_TST(1, dst, src), ctx); |
| goto emit_cond_jmp; |
| /* IF (dst COND imm) JUMP off */ |
| 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: |
| case BPF_JMP | BPF_JNE | BPF_K: |
| 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: |
| emit_a64_mov_i(1, tmp, imm, ctx); |
| emit(A64_CMP(1, dst, tmp), ctx); |
| goto emit_cond_jmp; |
| case BPF_JMP | BPF_JSET | BPF_K: |
| emit_a64_mov_i(1, tmp, imm, ctx); |
| emit(A64_TST(1, dst, tmp), ctx); |
| goto emit_cond_jmp; |
| /* function call */ |
| case BPF_JMP | BPF_CALL: |
| { |
| const u8 r0 = bpf2a64[BPF_REG_0]; |
| bool func_addr_fixed; |
| u64 func_addr; |
| int ret; |
| |
| ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass, |
| &func_addr, &func_addr_fixed); |
| if (ret < 0) |
| return ret; |
| emit_addr_mov_i64(tmp, func_addr, ctx); |
| emit(A64_BLR(tmp), ctx); |
| emit(A64_MOV(1, r0, A64_R(0)), ctx); |
| break; |
| } |
| /* tail call */ |
| case BPF_JMP | BPF_TAIL_CALL: |
| if (emit_bpf_tail_call(ctx)) |
| return -EFAULT; |
| 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_imm26(jmp_offset); |
| emit(A64_B(jmp_offset), ctx); |
| break; |
| |
| /* dst = imm64 */ |
| case BPF_LD | BPF_IMM | BPF_DW: |
| { |
| const struct bpf_insn insn1 = insn[1]; |
| u64 imm64; |
| |
| imm64 = (u64)insn1.imm << 32 | (u32)imm; |
| emit_a64_mov_i64(dst, imm64, 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: |
| emit_a64_mov_i(1, tmp, off, ctx); |
| switch (BPF_SIZE(code)) { |
| case BPF_W: |
| emit(A64_LDR32(dst, src, tmp), ctx); |
| break; |
| case BPF_H: |
| emit(A64_LDRH(dst, src, tmp), ctx); |
| break; |
| case BPF_B: |
| emit(A64_LDRB(dst, src, tmp), ctx); |
| break; |
| case BPF_DW: |
| emit(A64_LDR64(dst, src, tmp), ctx); |
| break; |
| } |
| 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: |
| /* Load imm to a register then store it */ |
| emit_a64_mov_i(1, tmp2, off, ctx); |
| emit_a64_mov_i(1, tmp, imm, ctx); |
| switch (BPF_SIZE(code)) { |
| case BPF_W: |
| emit(A64_STR32(tmp, dst, tmp2), ctx); |
| break; |
| case BPF_H: |
| emit(A64_STRH(tmp, dst, tmp2), ctx); |
| break; |
| case BPF_B: |
| emit(A64_STRB(tmp, dst, tmp2), ctx); |
| break; |
| case BPF_DW: |
| emit(A64_STR64(tmp, dst, tmp2), ctx); |
| break; |
| } |
| break; |
| |
| /* 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: |
| emit_a64_mov_i(1, tmp, off, ctx); |
| switch (BPF_SIZE(code)) { |
| case BPF_W: |
| emit(A64_STR32(src, dst, tmp), ctx); |
| break; |
| case BPF_H: |
| emit(A64_STRH(src, dst, tmp), ctx); |
| break; |
| case BPF_B: |
| emit(A64_STRB(src, dst, tmp), ctx); |
| break; |
| case BPF_DW: |
| emit(A64_STR64(src, dst, tmp), ctx); |
| break; |
| } |
| 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: |
| emit_a64_mov_i(1, tmp, off, ctx); |
| emit(A64_ADD(1, tmp, tmp, dst), ctx); |
| emit(A64_PRFM(tmp, PST, L1, STRM), ctx); |
| emit(A64_LDXR(isdw, tmp2, tmp), ctx); |
| emit(A64_ADD(isdw, tmp2, tmp2, src), ctx); |
| emit(A64_STXR(isdw, tmp2, tmp, tmp3), ctx); |
| jmp_offset = -3; |
| check_imm19(jmp_offset); |
| emit(A64_CBNZ(0, tmp3, jmp_offset), ctx); |
| break; |
| |
| default: |
| pr_err_once("unknown opcode %02x\n", code); |
| return -EINVAL; |
| } |
| |
| return 0; |
| } |
| |
| static int build_body(struct jit_ctx *ctx, bool extra_pass) |
| { |
| const struct bpf_prog *prog = ctx->prog; |
| int i; |
| |
| for (i = 0; i < prog->len; i++) { |
| const struct bpf_insn *insn = &prog->insnsi[i]; |
| int ret; |
| |
| ret = build_insn(insn, ctx, extra_pass); |
| if (ret > 0) { |
| i++; |
| if (ctx->image == NULL) |
| ctx->offset[i] = ctx->idx; |
| continue; |
| } |
| if (ctx->image == NULL) |
| ctx->offset[i] = ctx->idx; |
| if (ret) |
| return ret; |
| } |
| |
| return 0; |
| } |
| |
| static int validate_code(struct jit_ctx *ctx) |
| { |
| int i; |
| |
| for (i = 0; i < ctx->idx; i++) { |
| u32 a64_insn = le32_to_cpu(ctx->image[i]); |
| |
| if (a64_insn == AARCH64_BREAK_FAULT) |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| static inline void bpf_flush_icache(void *start, void *end) |
| { |
| flush_icache_range((unsigned long)start, (unsigned long)end); |
| } |
| |
| struct arm64_jit_data { |
| struct bpf_binary_header *header; |
| u8 *image; |
| struct jit_ctx ctx; |
| }; |
| |
| struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) |
| { |
| struct bpf_prog *tmp, *orig_prog = prog; |
| struct bpf_binary_header *header; |
| struct arm64_jit_data *jit_data; |
| bool was_classic = bpf_prog_was_classic(prog); |
| bool tmp_blinded = false; |
| bool extra_pass = false; |
| struct jit_ctx ctx; |
| int image_size; |
| u8 *image_ptr; |
| |
| if (!prog->jit_requested) |
| return orig_prog; |
| |
| tmp = bpf_jit_blind_constants(prog); |
| /* If blinding was requested and we failed during blinding, |
| * we must fall back to the interpreter. |
| */ |
| if (IS_ERR(tmp)) |
| return orig_prog; |
| if (tmp != prog) { |
| tmp_blinded = true; |
| prog = tmp; |
| } |
| |
| jit_data = prog->aux->jit_data; |
| if (!jit_data) { |
| jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL); |
| if (!jit_data) { |
| prog = orig_prog; |
| goto out; |
| } |
| prog->aux->jit_data = jit_data; |
| } |
| if (jit_data->ctx.offset) { |
| ctx = jit_data->ctx; |
| image_ptr = jit_data->image; |
| header = jit_data->header; |
| extra_pass = true; |
| image_size = sizeof(u32) * ctx.idx; |
| goto skip_init_ctx; |
| } |
| memset(&ctx, 0, sizeof(ctx)); |
| ctx.prog = prog; |
| |
| ctx.offset = kcalloc(prog->len, sizeof(int), GFP_KERNEL); |
| if (ctx.offset == NULL) { |
| prog = orig_prog; |
| goto out_off; |
| } |
| |
| /* 1. Initial fake pass to compute ctx->idx. */ |
| |
| /* Fake pass to fill in ctx->offset. */ |
| if (build_body(&ctx, extra_pass)) { |
| prog = orig_prog; |
| goto out_off; |
| } |
| |
| if (build_prologue(&ctx, was_classic)) { |
| prog = orig_prog; |
| goto out_off; |
| } |
| |
| ctx.epilogue_offset = ctx.idx; |
| build_epilogue(&ctx); |
| |
| /* Now we know the actual image size. */ |
| image_size = sizeof(u32) * ctx.idx; |
| header = bpf_jit_binary_alloc(image_size, &image_ptr, |
| sizeof(u32), jit_fill_hole); |
| if (header == NULL) { |
| prog = orig_prog; |
| goto out_off; |
| } |
| |
| /* 2. Now, the actual pass. */ |
| |
| ctx.image = (__le32 *)image_ptr; |
| skip_init_ctx: |
| ctx.idx = 0; |
| |
| build_prologue(&ctx, was_classic); |
| |
| if (build_body(&ctx, extra_pass)) { |
| bpf_jit_binary_free(header); |
| prog = orig_prog; |
| goto out_off; |
| } |
| |
| build_epilogue(&ctx); |
| |
| /* 3. Extra pass to validate JITed code. */ |
| if (validate_code(&ctx)) { |
| bpf_jit_binary_free(header); |
| prog = orig_prog; |
| goto out_off; |
| } |
| |
| /* And we're done. */ |
| if (bpf_jit_enable > 1) |
| bpf_jit_dump(prog->len, image_size, 2, ctx.image); |
| |
| bpf_flush_icache(header, ctx.image + ctx.idx); |
| |
| if (!prog->is_func || extra_pass) { |
| if (extra_pass && ctx.idx != jit_data->ctx.idx) { |
| pr_err_once("multi-func JIT bug %d != %d\n", |
| ctx.idx, jit_data->ctx.idx); |
| bpf_jit_binary_free(header); |
| prog->bpf_func = NULL; |
| prog->jited = 0; |
| goto out_off; |
| } |
| bpf_jit_binary_lock_ro(header); |
| } else { |
| jit_data->ctx = ctx; |
| jit_data->image = image_ptr; |
| jit_data->header = header; |
| } |
| prog->bpf_func = (void *)ctx.image; |
| prog->jited = 1; |
| prog->jited_len = image_size; |
| |
| if (!prog->is_func || extra_pass) { |
| bpf_prog_fill_jited_linfo(prog, ctx.offset); |
| out_off: |
| kfree(ctx.offset); |
| kfree(jit_data); |
| prog->aux->jit_data = NULL; |
| } |
| out: |
| if (tmp_blinded) |
| bpf_jit_prog_release_other(prog, prog == orig_prog ? |
| tmp : orig_prog); |
| return prog; |
| } |
| |
| void *bpf_jit_alloc_exec(unsigned long size) |
| { |
| return __vmalloc_node_range(size, PAGE_SIZE, BPF_JIT_REGION_START, |
| BPF_JIT_REGION_END, GFP_KERNEL, |
| PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, |
| __builtin_return_address(0)); |
| } |
| |
| void bpf_jit_free_exec(void *addr) |
| { |
| return vfree(addr); |
| } |