diff options
Diffstat (limited to 'arch/arm/net/bpf_jit_32.c')
| -rw-r--r-- | arch/arm/net/bpf_jit_32.c | 1993 |
1 files changed, 1993 insertions, 0 deletions
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c new file mode 100644 index 000000000..dade3a3ba --- /dev/null +++ b/arch/arm/net/bpf_jit_32.c @@ -0,0 +1,1993 @@ +/* + * Just-In-Time compiler for eBPF filters on 32bit ARM + * + * Copyright (c) 2017 Shubham Bansal <illusionist.neo@gmail.com> + * Copyright (c) 2011 Mircea Gherzan <mgherzan@gmail.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; version 2 of the License. + */ + +#include <linux/bpf.h> +#include <linux/bitops.h> +#include <linux/compiler.h> +#include <linux/errno.h> +#include <linux/filter.h> +#include <linux/netdevice.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/if_vlan.h> + +#include <asm/cacheflush.h> +#include <asm/hwcap.h> +#include <asm/opcodes.h> +#include <asm/system_info.h> + +#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); + 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); + /* 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_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_MI, ARM_B(0), ctx); + emit(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); + emit_a32_mov_i(rd[0], 0, ctx); + break; + case BPF_H: + /* Load a HalfWord */ + emit(ARM_LDRH_I(rd[1], rm, off), ctx); + emit_a32_mov_i(rd[0], 0, ctx); + break; + case BPF_W: + /* Load a Word */ + emit(ARM_LDR_I(rd[1], rm, off), ctx); + 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) { + switch (op) { + case BPF_JSET: + 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); + break; + case BPF_JEQ: + case BPF_JNE: + case BPF_JGT: + case BPF_JGE: + case BPF_JLE: + case BPF_JLT: + emit(ARM_CMP_R(rd, rm), ctx); + _emit(ARM_COND_EQ, ARM_CMP_R(rt, rn), ctx); + break; + case BPF_JSLE: + case BPF_JSGT: + emit(ARM_CMP_R(rn, rt), ctx); + emit(ARM_SBCS_R(ARM_IP, rm, rd), ctx); + break; + case BPF_JSLT: + case BPF_JSGE: + emit(ARM_CMP_R(rt, rn), ctx); + 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 r0 = bpf2a32[BPF_REG_0][1]; + const s8 r2 = bpf2a32[BPF_REG_1][1]; + const s8 r3 = bpf2a32[BPF_REG_1][0]; + const s8 r4 = bpf2a32[BPF_REG_6][1]; + const s8 fplo = bpf2a32[BPF_REG_FP][1]; + const s8 fphi = bpf2a32[BPF_REG_FP][0]; + 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 + /* Save frame pointer for later */ + emit(ARM_SUB_I(ARM_IP, 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_r(fplo, ARM_IP, ctx); + emit_a32_mov_i(fphi, 0, ctx); + + /* mov r4, 0 */ + emit(ARM_MOV_I(r4, 0), ctx); + + /* Move BPF_CTX to BPF_R1 */ + emit(ARM_MOV_R(r3, r4), ctx); + emit(ARM_MOV_R(r2, r0), ctx); + /* Initialize Tail Count */ + emit(ARM_STR_I(r4, ARM_FP, EBPF_SCRATCH_TO_ARM_FP(tcc[0])), ctx); + emit(ARM_STR_I(r4, ARM_FP, EBPF_SCRATCH_TO_ARM_FP(tcc[1])), 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: + 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_K: + 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); + 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 */ + case BPF_ALU | BPF_RSH | BPF_K: + case BPF_ALU | BPF_LSH | BPF_K: + if (unlikely(imm > 31)) + return -EINVAL; + if (imm) + emit_a32_alu_i(dst_lo, imm, ctx, BPF_OP(code)); + 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)); + 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 + emit(ARM_EOR_R(rd[0], rd[0], rd[0]), ctx); + break; + case 32: + /* zero-extend 32 bits into 64 bits */ + 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: + /* 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: + 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)); + + /* 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. */ +} + +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; +} + |