--- /dev/null
+/*
+ * BPF JIT compiler for ARM64
+ *
+ * Copyright (C) 2014 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/filter.h>
+#include <linux/printk.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+
+#include <asm/byteorder.h>
+#include <asm/cacheflush.h>
+#include <asm/debug-monitors.h>
+
+#include "bpf_jit.h"
+
+int bpf_jit_enable __read_mostly;
+
+#define TMP_REG_1 (MAX_BPF_REG + 0)
+#define TMP_REG_2 (MAX_BPF_REG + 1)
+
+/* 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_FP,
+ /* temporary register for internal BPF JIT */
+ [TMP_REG_1] = A64_R(23),
+ [TMP_REG_2] = A64_R(24),
+};
+
+struct jit_ctx {
+ const struct bpf_prog *prog;
+ int idx;
+ int tmp_used;
+ int epilogue_offset;
+ int *offset;
+ u32 *image;
+};
+
+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_i64(const int reg, const u64 val,
+ struct jit_ctx *ctx)
+{
+ u64 tmp = val;
+ int shift = 0;
+
+ emit(A64_MOVZ(1, reg, tmp & 0xffff, shift), ctx);
+ tmp >>= 16;
+ shift += 16;
+ while (tmp) {
+ if (tmp & 0xffff)
+ emit(A64_MOVK(1, reg, tmp & 0xffff, shift), ctx);
+ tmp >>= 16;
+ shift += 16;
+ }
+}
+
+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);
+ 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 inline int bpf2a64_offset(int bpf_to, int bpf_from,
+ const struct jit_ctx *ctx)
+{
+ int to = ctx->offset[bpf_to + 1];
+ /* -1 to account for the Branch instruction */
+ int from = ctx->offset[bpf_from + 1] - 1;
+
+ return to - from;
+}
+
+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++ = 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)
+
+static void build_prologue(struct jit_ctx *ctx)
+{
+ 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 ra = bpf2a64[BPF_REG_A];
+ const u8 rx = bpf2a64[BPF_REG_X];
+ const u8 tmp1 = bpf2a64[TMP_REG_1];
+ const u8 tmp2 = bpf2a64[TMP_REG_2];
+ int stack_size = MAX_BPF_STACK;
+
+ stack_size += 4; /* extra for skb_copy_bits buffer */
+ stack_size = STACK_ALIGN(stack_size);
+
+ /* Save callee-saved register */
+ emit(A64_PUSH(r6, r7, A64_SP), ctx);
+ emit(A64_PUSH(r8, r9, A64_SP), ctx);
+ if (ctx->tmp_used)
+ emit(A64_PUSH(tmp1, tmp2, A64_SP), ctx);
+
+ /* Set up BPF stack */
+ emit(A64_SUB_I(1, A64_SP, A64_SP, stack_size), ctx);
+
+ /* Set up frame pointer */
+ emit(A64_MOV(1, fp, A64_SP), ctx);
+
+ /* Clear registers A and X */
+ emit_a64_mov_i64(ra, 0, ctx);
+ emit_a64_mov_i64(rx, 0, ctx);
+}
+
+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];
+ const u8 tmp1 = bpf2a64[TMP_REG_1];
+ const u8 tmp2 = bpf2a64[TMP_REG_2];
+ int stack_size = MAX_BPF_STACK;
+
+ stack_size += 4; /* extra for skb_copy_bits buffer */
+ stack_size = STACK_ALIGN(stack_size);
+
+ /* We're done with BPF stack */
+ emit(A64_ADD_I(1, A64_SP, A64_SP, stack_size), ctx);
+
+ /* Restore callee-saved register */
+ if (ctx->tmp_used)
+ emit(A64_POP(tmp1, tmp2, A64_SP), ctx);
+ emit(A64_POP(r8, r9, A64_SP), ctx);
+ emit(A64_POP(r6, r7, A64_SP), ctx);
+
+ /* Restore frame pointer */
+ emit(A64_MOV(1, fp, 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)
+{
+ 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 s16 off = insn->off;
+ const s32 imm = insn->imm;
+ const int i = insn - ctx->prog->insnsi;
+ const bool is64 = BPF_CLASS(code) == BPF_ALU64;
+ u8 jmp_cond;
+ s32 jmp_offset;
+
+ 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:
+ emit(A64_UDIV(is64, dst, dst, src), ctx);
+ break;
+ case BPF_ALU | BPF_MOD | BPF_X:
+ case BPF_ALU64 | BPF_MOD | BPF_X:
+ ctx->tmp_used = 1;
+ 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;
+ 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)
+ break;
+#else /* !CONFIG_CPU_BIG_ENDIAN */
+ if (BPF_SRC(code) == BPF_FROM_LE)
+ break;
+#endif
+ switch (imm) {
+ case 16:
+ emit(A64_REV16(is64, dst, dst), ctx);
+ break;
+ case 32:
+ emit(A64_REV32(is64, dst, dst), ctx);
+ break;
+ case 64:
+ emit(A64_REV64(dst, dst), ctx);
+ 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:
+ ctx->tmp_used = 1;
+ 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:
+ ctx->tmp_used = 1;
+ 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:
+ ctx->tmp_used = 1;
+ 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:
+ ctx->tmp_used = 1;
+ 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:
+ ctx->tmp_used = 1;
+ 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:
+ ctx->tmp_used = 1;
+ 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:
+ ctx->tmp_used = 1;
+ 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:
+ ctx->tmp_used = 1;
+ 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;
+
+#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)
+
+ /* 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_JGE | BPF_X:
+ case BPF_JMP | BPF_JNE | BPF_X:
+ case BPF_JMP | BPF_JSGT | BPF_X:
+ case BPF_JMP | BPF_JSGE | 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_JGE:
+ jmp_cond = A64_COND_CS;
+ break;
+ case BPF_JNE:
+ jmp_cond = A64_COND_NE;
+ break;
+ case BPF_JSGT:
+ jmp_cond = A64_COND_GT;
+ break;
+ case BPF_JSGE:
+ jmp_cond = A64_COND_GE;
+ 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_JGE | BPF_K:
+ case BPF_JMP | BPF_JNE | BPF_K:
+ case BPF_JMP | BPF_JSGT | BPF_K:
+ case BPF_JMP | BPF_JSGE | BPF_K:
+ ctx->tmp_used = 1;
+ 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:
+ ctx->tmp_used = 1;
+ 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];
+ const u64 func = (u64)__bpf_call_base + imm;
+
+ ctx->tmp_used = 1;
+ emit_a64_mov_i64(tmp, func, ctx);
+ emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
+ emit(A64_MOV(1, A64_FP, A64_SP), ctx);
+ emit(A64_BLR(tmp), ctx);
+ emit(A64_MOV(1, r0, A64_R(0)), ctx);
+ emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
+ 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;
+
+ if (insn1.code != 0 || insn1.src_reg != 0 ||
+ insn1.dst_reg != 0 || insn1.off != 0) {
+ /* Note: verifier in BPF core must catch invalid
+ * instructions.
+ */
+ pr_err_once("Invalid BPF_LD_IMM64 instruction\n");
+ return -EINVAL;
+ }
+
+ 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:
+ ctx->tmp_used = 1;
+ 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:
+ 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:
+ ctx->tmp_used = 1;
+ 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:
+ goto notyet;
+
+ /* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + imm)) */
+ case BPF_LD | BPF_ABS | BPF_W:
+ case BPF_LD | BPF_ABS | BPF_H:
+ case BPF_LD | BPF_ABS | BPF_B:
+ /* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + src + imm)) */
+ case BPF_LD | BPF_IND | BPF_W:
+ case BPF_LD | BPF_IND | BPF_H:
+ case BPF_LD | BPF_IND | BPF_B:
+ {
+ const u8 r0 = bpf2a64[BPF_REG_0]; /* r0 = return value */
+ const u8 r6 = bpf2a64[BPF_REG_6]; /* r6 = pointer to sk_buff */
+ const u8 fp = bpf2a64[BPF_REG_FP];
+ const u8 r1 = bpf2a64[BPF_REG_1]; /* r1: struct sk_buff *skb */
+ const u8 r2 = bpf2a64[BPF_REG_2]; /* r2: int k */
+ const u8 r3 = bpf2a64[BPF_REG_3]; /* r3: unsigned int size */
+ const u8 r4 = bpf2a64[BPF_REG_4]; /* r4: void *buffer */
+ const u8 r5 = bpf2a64[BPF_REG_5]; /* r5: void *(*func)(...) */
+ int size;
+
+ emit(A64_MOV(1, r1, r6), ctx);
+ emit_a64_mov_i(0, r2, imm, ctx);
+ if (BPF_MODE(code) == BPF_IND)
+ emit(A64_ADD(0, r2, r2, src), ctx);
+ switch (BPF_SIZE(code)) {
+ case BPF_W:
+ size = 4;
+ break;
+ case BPF_H:
+ size = 2;
+ break;
+ case BPF_B:
+ size = 1;
+ break;
+ default:
+ return -EINVAL;
+ }
+ emit_a64_mov_i64(r3, size, ctx);
+ emit(A64_ADD_I(1, r4, fp, MAX_BPF_STACK), ctx);
+ emit_a64_mov_i64(r5, (unsigned long)bpf_load_pointer, ctx);
+ emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
+ emit(A64_MOV(1, A64_FP, A64_SP), ctx);
+ emit(A64_BLR(r5), ctx);
+ emit(A64_MOV(1, r0, A64_R(0)), ctx);
+ emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
+
+ jmp_offset = epilogue_offset(ctx);
+ check_imm19(jmp_offset);
+ emit(A64_CBZ(1, r0, jmp_offset), ctx);
+ emit(A64_MOV(1, r5, r0), ctx);
+ switch (BPF_SIZE(code)) {
+ case BPF_W:
+ emit(A64_LDR32(r0, r5, A64_ZR), ctx);
+#ifndef CONFIG_CPU_BIG_ENDIAN
+ emit(A64_REV32(0, r0, r0), ctx);
+#endif
+ break;
+ case BPF_H:
+ emit(A64_LDRH(r0, r5, A64_ZR), ctx);
+#ifndef CONFIG_CPU_BIG_ENDIAN
+ emit(A64_REV16(0, r0, r0), ctx);
+#endif
+ break;
+ case BPF_B:
+ emit(A64_LDRB(r0, r5, A64_ZR), ctx);
+ break;
+ }
+ break;
+ }
+notyet:
+ pr_info_once("*** NOT YET: opcode %02x ***\n", code);
+ return -EFAULT;
+
+ default:
+ pr_err_once("unknown opcode %02x\n", code);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int build_body(struct jit_ctx *ctx)
+{
+ 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;
+
+ if (ctx->image == NULL)
+ ctx->offset[i] = ctx->idx;
+
+ ret = build_insn(insn, ctx);
+ if (ret > 0) {
+ i++;
+ continue;
+ }
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static inline void bpf_flush_icache(void *start, void *end)
+{
+ flush_icache_range((unsigned long)start, (unsigned long)end);
+}
+
+void bpf_jit_compile(struct bpf_prog *prog)
+{
+ /* Nothing to do here. We support Internal BPF. */
+}
+
+void bpf_int_jit_compile(struct bpf_prog *prog)
+{
+ struct bpf_binary_header *header;
+ struct jit_ctx ctx;
+ int image_size;
+ u8 *image_ptr;
+
+ if (!bpf_jit_enable)
+ return;
+
+ if (!prog || !prog->len)
+ return;
+
+ memset(&ctx, 0, sizeof(ctx));
+ ctx.prog = prog;
+
+ ctx.offset = kcalloc(prog->len, sizeof(int), GFP_KERNEL);
+ if (ctx.offset == NULL)
+ return;
+
+ /* 1. Initial fake pass to compute ctx->idx. */
+
+ /* Fake pass to fill in ctx->offset and ctx->tmp_used. */
+ if (build_body(&ctx))
+ goto out;
+
+ build_prologue(&ctx);
+
+ 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)
+ goto out;
+
+ /* 2. Now, the actual pass. */
+
+ ctx.image = (u32 *)image_ptr;
+ ctx.idx = 0;
+
+ build_prologue(&ctx);
+
+ if (build_body(&ctx)) {
+ bpf_jit_binary_free(header);
+ goto out;
+ }
+
+ build_epilogue(&ctx);
+
+ /* And we're done. */
+ if (bpf_jit_enable > 1)
+ bpf_jit_dump(prog->len, image_size, 2, ctx.image);
+
+ bpf_flush_icache(ctx.image, ctx.image + ctx.idx);
+
+ set_memory_ro((unsigned long)header, header->pages);
+ prog->bpf_func = (void *)ctx.image;
+ prog->jited = true;
+out:
+ kfree(ctx.offset);
+}
+
+void bpf_jit_free(struct bpf_prog *prog)
+{
+ unsigned long addr = (unsigned long)prog->bpf_func & PAGE_MASK;
+ struct bpf_binary_header *header = (void *)addr;
+
+ if (!prog->jited)
+ goto free_filter;
+
+ set_memory_rw(addr, header->pages);
+ bpf_jit_binary_free(header);
+
+free_filter:
+ bpf_prog_unlock_free(prog);
+}
Code Review / kvmfornfv.git / blobdiff