diff options
author | Shubham Bansal <illusionist.neo@gmail.com> | 2017-08-22 12:02:33 +0530 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2017-08-22 09:26:43 -0700 |
commit | 39c13c204bb1150d401e27d41a9d8b332be47c49 (patch) | |
tree | 5b227810abdecca21fad1181a83b0820efc0c82f /arch/arm/net/bpf_jit_32.c | |
parent | e2a7c34fb2856fd5306e307e170e3dde358d0dce (diff) |
arm: eBPF JIT compiler
The JIT compiler emits ARM 32 bit instructions. Currently, It supports
eBPF only. Classic BPF is supported because of the conversion by BPF core.
This patch is essentially changing the current implementation of JIT compiler
of Berkeley Packet Filter from classic to internal with almost all
instructions from eBPF ISA supported except the following
BPF_ALU64 | BPF_DIV | BPF_K
BPF_ALU64 | BPF_DIV | BPF_X
BPF_ALU64 | BPF_MOD | BPF_K
BPF_ALU64 | BPF_MOD | BPF_X
BPF_STX | BPF_XADD | BPF_W
BPF_STX | BPF_XADD | BPF_DW
Implementation is using scratch space to emulate 64 bit eBPF ISA on 32 bit
ARM because of deficiency of general purpose registers on ARM. Currently,
only LITTLE ENDIAN machines are supported in this eBPF JIT Compiler.
Tested on ARMv7 with QEMU by me (Shubham Bansal).
Testing results on ARMv7:
1) test_bpf: Summary: 341 PASSED, 0 FAILED, [312/333 JIT'ed]
2) test_tag: OK (40945 tests)
3) test_progs: Summary: 30 PASSED, 0 FAILED
4) test_lpm: OK
5) test_lru_map: OK
Above tests are all done with following flags enabled discreatly.
1) bpf_jit_enable=1
a) CONFIG_FRAME_POINTER enabled
b) CONFIG_FRAME_POINTER disabled
2) bpf_jit_enable=1 and bpf_jit_harden=2
a) CONFIG_FRAME_POINTER enabled
b) CONFIG_FRAME_POINTER disabled
See Documentation/networking/filter.txt for more information.
Signed-off-by: Shubham Bansal <illusionist.neo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/arm/net/bpf_jit_32.c')
-rw-r--r-- | arch/arm/net/bpf_jit_32.c | 2448 |
1 files changed, 1663 insertions, 785 deletions
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index d5b9fa19b684..c199990e12b6 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -1,6 +1,7 @@ /* - * Just-In-Time compiler for BPF filters on 32bit ARM + * 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 @@ -8,6 +9,7 @@ * Free Software Foundation; version 2 of the License. */ +#include <linux/bpf.h> #include <linux/bitops.h> #include <linux/compiler.h> #include <linux/errno.h> @@ -18,54 +20,101 @@ #include <linux/if_vlan.h> #include <asm/cacheflush.h> -#include <asm/set_memory.h> #include <asm/hwcap.h> #include <asm/opcodes.h> #include "bpf_jit_32.h" +int bpf_jit_enable __read_mostly; + +#define STACK_OFFSET(k) (k) +#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 */ + +/* Flags used for JIT optimization */ +#define SEEN_CALL (1 << 0) + +#define FLAG_IMM_OVERFLOW (1 << 0) + /* - * ABI: + * 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 arugument 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. * - * r0 scratch register - * r4 BPF register A - * r5 BPF register X - * r6 pointer to the skb - * r7 skb->data - * r8 skb_headlen(skb) */ +static const u8 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(0), STACK_OFFSET(4)}, + [BPF_REG_3] = {STACK_OFFSET(8), STACK_OFFSET(12)}, + [BPF_REG_4] = {STACK_OFFSET(16), STACK_OFFSET(20)}, + [BPF_REG_5] = {STACK_OFFSET(24), STACK_OFFSET(28)}, + /* 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(32), STACK_OFFSET(36)}, + [BPF_REG_8] = {STACK_OFFSET(40), STACK_OFFSET(44)}, + [BPF_REG_9] = {STACK_OFFSET(48), STACK_OFFSET(52)}, + /* Read only Frame Pointer to access Stack */ + [BPF_REG_FP] = {STACK_OFFSET(56), STACK_OFFSET(60)}, + /* 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_R10, ARM_R8}, + /* Tail call count. Stored on stack scratch space. */ + [TCALL_CNT] = {STACK_OFFSET(64), STACK_OFFSET(68)}, + /* temporary register for blinding constants. + * Stored on stack scratch space. + */ + [BPF_REG_AX] = {STACK_OFFSET(72), STACK_OFFSET(76)}, +}; -#define r_scratch ARM_R0 -/* r1-r3 are (also) used for the unaligned loads on the non-ARMv7 slowpath */ -#define r_off ARM_R1 -#define r_A ARM_R4 -#define r_X ARM_R5 -#define r_skb ARM_R6 -#define r_skb_data ARM_R7 -#define r_skb_hl ARM_R8 - -#define SCRATCH_SP_OFFSET 0 -#define SCRATCH_OFF(k) (SCRATCH_SP_OFFSET + 4 * (k)) - -#define SEEN_MEM ((1 << BPF_MEMWORDS) - 1) -#define SEEN_MEM_WORD(k) (1 << (k)) -#define SEEN_X (1 << BPF_MEMWORDS) -#define SEEN_CALL (1 << (BPF_MEMWORDS + 1)) -#define SEEN_SKB (1 << (BPF_MEMWORDS + 2)) -#define SEEN_DATA (1 << (BPF_MEMWORDS + 3)) +#define dst_lo dst[1] +#define dst_hi dst[0] +#define src_lo src[1] +#define src_hi src[0] -#define FLAG_NEED_X_RESET (1 << 0) -#define FLAG_IMM_OVERFLOW (1 << 1) +/* + * JIT Context: + * + * prog : bpf_prog + * idx : index of current last JITed instruction. + * prologue_bytes : bytes used in prologue. + * epilogue_offset : offset of epilogue starting. + * seen : bit mask used for JIT optimization. + * 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 *skf; - unsigned idx; - unsigned prologue_bytes; - int ret0_fp_idx; + const struct bpf_prog *prog; + unsigned int idx; + unsigned int prologue_bytes; + unsigned int epilogue_offset; u32 seen; u32 flags; u32 *offsets; u32 *target; + u32 stack_size; #if __LINUX_ARM_ARCH__ < 7 u16 epilogue_bytes; u16 imm_count; @@ -73,68 +122,16 @@ struct jit_ctx { #endif }; -int bpf_jit_enable __read_mostly; - -static inline int call_neg_helper(struct sk_buff *skb, int offset, void *ret, - unsigned int size) -{ - void *ptr = bpf_internal_load_pointer_neg_helper(skb, offset, size); - - if (!ptr) - return -EFAULT; - memcpy(ret, ptr, size); - return 0; -} - -static u64 jit_get_skb_b(struct sk_buff *skb, int offset) -{ - u8 ret; - int err; - - if (offset < 0) - err = call_neg_helper(skb, offset, &ret, 1); - else - err = skb_copy_bits(skb, offset, &ret, 1); - - return (u64)err << 32 | ret; -} - -static u64 jit_get_skb_h(struct sk_buff *skb, int offset) -{ - u16 ret; - int err; - - if (offset < 0) - err = call_neg_helper(skb, offset, &ret, 2); - else - err = skb_copy_bits(skb, offset, &ret, 2); - - return (u64)err << 32 | ntohs(ret); -} - -static u64 jit_get_skb_w(struct sk_buff *skb, int offset) -{ - u32 ret; - int err; - - if (offset < 0) - err = call_neg_helper(skb, offset, &ret, 4); - else - err = skb_copy_bits(skb, offset, &ret, 4); - - return (u64)err << 32 | ntohl(ret); -} - /* * Wrappers which handle both OABI and EABI and assures Thumb2 interworking * (where the assembly routines like __aeabi_uidiv could cause problems). */ -static u32 jit_udiv(u32 dividend, u32 divisor) +static u32 jit_udiv32(u32 dividend, u32 divisor) { return dividend / divisor; } -static u32 jit_mod(u32 dividend, u32 divisor) +static u32 jit_mod32(u32 dividend, u32 divisor) { return dividend % divisor; } @@ -158,36 +155,22 @@ static inline void emit(u32 inst, struct jit_ctx *ctx) _emit(ARM_COND_AL, inst, ctx); } -static u16 saved_regs(struct jit_ctx *ctx) +/* + * Checks if immediate value can be converted to imm12(12 bits) value. + */ +static int16_t imm8m(u32 x) { - u16 ret = 0; - - if ((ctx->skf->len > 1) || - (ctx->skf->insns[0].code == (BPF_RET | BPF_A))) - ret |= 1 << r_A; - -#ifdef CONFIG_FRAME_POINTER - ret |= (1 << ARM_FP) | (1 << ARM_IP) | (1 << ARM_LR) | (1 << ARM_PC); -#else - if (ctx->seen & SEEN_CALL) - ret |= 1 << ARM_LR; -#endif - if (ctx->seen & (SEEN_DATA | SEEN_SKB)) - ret |= 1 << r_skb; - if (ctx->seen & SEEN_DATA) - ret |= (1 << r_skb_data) | (1 << r_skb_hl); - if (ctx->seen & SEEN_X) - ret |= 1 << r_X; - - return ret; -} + u32 rot; -static inline int mem_words_used(struct jit_ctx *ctx) -{ - /* yes, we do waste some stack space IF there are "holes" in the set" */ - return fls(ctx->seen & SEEN_MEM); + for (rot = 0; rot < 16; rot++) + if ((x & ~ror32(0xff, 2 * rot)) == 0) + return rol32(x, 2 * rot) | (rot << 8); + return -1; } +/* + * Initializes the JIT space with undefined instructions. + */ static void jit_fill_hole(void *area, unsigned int size) { u32 *ptr; @@ -196,88 +179,34 @@ static void jit_fill_hole(void *area, unsigned int size) *ptr++ = __opcode_to_mem_arm(ARM_INST_UDF); } -static void build_prologue(struct jit_ctx *ctx) -{ - u16 reg_set = saved_regs(ctx); - u16 off; - -#ifdef CONFIG_FRAME_POINTER - 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 - if (reg_set) - emit(ARM_PUSH(reg_set), ctx); -#endif - - if (ctx->seen & (SEEN_DATA | SEEN_SKB)) - emit(ARM_MOV_R(r_skb, ARM_R0), ctx); - - if (ctx->seen & SEEN_DATA) { - off = offsetof(struct sk_buff, data); - emit(ARM_LDR_I(r_skb_data, r_skb, off), ctx); - /* headlen = len - data_len */ - off = offsetof(struct sk_buff, len); - emit(ARM_LDR_I(r_skb_hl, r_skb, off), ctx); - off = offsetof(struct sk_buff, data_len); - emit(ARM_LDR_I(r_scratch, r_skb, off), ctx); - emit(ARM_SUB_R(r_skb_hl, r_skb_hl, r_scratch), ctx); - } - - if (ctx->flags & FLAG_NEED_X_RESET) - emit(ARM_MOV_I(r_X, 0), ctx); - - /* do not leak kernel data to userspace */ - if (bpf_needs_clear_a(&ctx->skf->insns[0])) - emit(ARM_MOV_I(r_A, 0), ctx); - - /* stack space for the BPF_MEM words */ - if (ctx->seen & SEEN_MEM) - emit(ARM_SUB_I(ARM_SP, ARM_SP, mem_words_used(ctx) * 4), ctx); -} - -static void build_epilogue(struct jit_ctx *ctx) -{ - u16 reg_set = saved_regs(ctx); - - if (ctx->seen & SEEN_MEM) - emit(ARM_ADD_I(ARM_SP, ARM_SP, mem_words_used(ctx) * 4), ctx); - - reg_set &= ~(1 << ARM_LR); +/* Stack must be multiples of 16 Bytes */ +#define STACK_ALIGN(sz) (((sz) + 3) & ~3) -#ifdef CONFIG_FRAME_POINTER - /* the first instruction of the prologue was: mov ip, sp */ - reg_set &= ~(1 << ARM_IP); - reg_set |= (1 << ARM_SP); - emit(ARM_LDM(ARM_SP, reg_set), ctx); -#else - if (reg_set) { - if (ctx->seen & SEEN_CALL) - reg_set |= 1 << ARM_PC; - emit(ARM_POP(reg_set), ctx); - } +/* 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. + */ +#define SCRATCH_SIZE 80 - if (!(ctx->seen & SEEN_CALL)) - emit(ARM_BX(ARM_LR), ctx); -#endif -} +/* total stack size used in JITed code */ +#define _STACK_SIZE \ + (ctx->prog->aux->stack_depth + \ + + SCRATCH_SIZE + \ + + 4 /* extra for skb_copy_bits buffer */) -static int16_t imm8m(u32 x) -{ - u32 rot; +#define STACK_SIZE STACK_ALIGN(_STACK_SIZE) - for (rot = 0; rot < 16; rot++) - if ((x & ~ror32(0xff, 2 * rot)) == 0) - return rol32(x, 2 * rot) | (rot << 8); +/* Get the offset of eBPF REGISTERs stored on scratch space. */ +#define STACK_VAR(off) (STACK_SIZE-off-4) - return -1; -} +/* Offset of skb_copy_bits buffer */ +#define SKB_BUFFER STACK_VAR(SCRATCH_SIZE) #if __LINUX_ARM_ARCH__ < 7 static u16 imm_offset(u32 k, struct jit_ctx *ctx) { - unsigned i = 0, offset; + unsigned int i = 0, offset; u16 imm; /* on the "fake" run we just count them (duplicates included) */ @@ -296,7 +225,7 @@ static u16 imm_offset(u32 k, struct jit_ctx *ctx) ctx->imms[i] = k; /* constants go just after the epilogue */ - offset = ctx->offsets[ctx->skf->len]; + offset = ctx->offsets[ctx->prog->len - 1] * 4; offset += ctx->prologue_bytes; offset += ctx->epilogue_bytes; offset += i * 4; @@ -320,10 +249,22 @@ static u16 imm_offset(u32 k, struct jit_ctx *ctx) #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(int rd, u32 val, struct jit_ctx *ctx) +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); @@ -334,7 +275,7 @@ static inline void emit_mov_i_no8m(int rd, u32 val, struct jit_ctx *ctx) #endif } -static inline void emit_mov_i(int rd, u32 val, struct jit_ctx *ctx) +static inline void emit_mov_i(const u8 rd, u32 val, struct jit_ctx *ctx) { int imm12 = imm8m(val); @@ -344,676 +285,1594 @@ static inline void emit_mov_i(int rd, u32 val, struct jit_ctx *ctx) emit_mov_i_no8m(rd, val, ctx); } -#if __LINUX_ARM_ARCH__ < 6 - -static void emit_load_be32(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx) +static inline void emit_blx_r(u8 tgt_reg, struct jit_ctx *ctx) { - _emit(cond, ARM_LDRB_I(ARM_R3, r_addr, 1), ctx); - _emit(cond, ARM_LDRB_I(ARM_R1, r_addr, 0), ctx); - _emit(cond, ARM_LDRB_I(ARM_R2, r_addr, 3), ctx); - _emit(cond, ARM_LSL_I(ARM_R3, ARM_R3, 16), ctx); - _emit(cond, ARM_LDRB_I(ARM_R0, r_addr, 2), ctx); - _emit(cond, ARM_ORR_S(ARM_R3, ARM_R3, ARM_R1, SRTYPE_LSL, 24), ctx); - _emit(cond, ARM_ORR_R(ARM_R3, ARM_R3, ARM_R2), ctx); - _emit(cond, ARM_ORR_S(r_res, ARM_R3, ARM_R0, SRTYPE_LSL, 8), ctx); + ctx->seen |= SEEN_CALL; +#if __LINUX_ARM_ARCH__ < 5 + emit(ARM_MOV_R(ARM_LR, ARM_PC), ctx); + + if (elf_hwcap & HWCAP_THUMB) + emit(ARM_BX(tgt_reg), ctx); + else + emit(ARM_MOV_R(ARM_PC, tgt_reg), ctx); +#else + emit(ARM_BLX_R(tgt_reg), ctx); +#endif } -static void emit_load_be16(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx) +static inline int epilogue_offset(const struct jit_ctx *ctx) { - _emit(cond, ARM_LDRB_I(ARM_R1, r_addr, 0), ctx); - _emit(cond, ARM_LDRB_I(ARM_R2, r_addr, 1), ctx); - _emit(cond, ARM_ORR_S(r_res, ARM_R2, ARM_R1, SRTYPE_LSL, 8), 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_swap16(u8 r_dst, u8 r_src, struct jit_ctx *ctx) +static inline void emit_udivmod(u8 rd, u8 rm, u8 rn, struct jit_ctx *ctx, u8 op) { - /* r_dst = (r_src << 8) | (r_src >> 8) */ - emit(ARM_LSL_I(ARM_R1, r_src, 8), ctx); - emit(ARM_ORR_S(r_dst, ARM_R1, r_src, SRTYPE_LSR, 8), ctx); + const u8 *tmp = bpf2a32[TMP_REG_1]; + s32 jmp_offset; + + /* checks if divisor is zero or not. If it is, then + * exit directly. + */ + emit(ARM_CMP_I(rn, 0), ctx); + _emit(ARM_COND_EQ, ARM_MOV_I(ARM_R0, 0), ctx); + jmp_offset = epilogue_offset(ctx); + _emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx); +#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 /* - * we need to mask out the bits set in r_dst[23:16] due to - * the first shift instruction. - * - * note that 0x8ff is the encoded immediate 0x00ff0000. + * 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. */ - emit(ARM_BIC_I(r_dst, r_dst, 0x8ff), ctx); -} + 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); + } -#else /* ARMv6+ */ + /* Call appropriate function */ + ctx->seen |= SEEN_CALL; + emit_mov_i(ARM_IP, op == BPF_DIV ? + (u32)jit_udiv32 : (u32)jit_mod32, ctx); + emit_blx_r(ARM_IP, ctx); -static void emit_load_be32(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx) -{ - _emit(cond, ARM_LDR_I(r_res, r_addr, 0), ctx); -#ifdef __LITTLE_ENDIAN - _emit(cond, ARM_REV(r_res, r_res), ctx); -#endif + /* 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); } -static void emit_load_be16(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx) +/* Checks whether BPF register is on scratch stack space or not. */ +static inline bool is_on_stack(u8 bpf_reg) { - _emit(cond, ARM_LDRH_I(r_res, r_addr, 0), ctx); -#ifdef __LITTLE_ENDIAN - _emit(cond, ARM_REV16(r_res, r_res), ctx); -#endif + static u8 stack_regs[] = {BPF_REG_AX, BPF_REG_3, BPF_REG_4, BPF_REG_5, + BPF_REG_7, BPF_REG_8, BPF_REG_9, TCALL_CNT, + BPF_REG_2, BPF_REG_FP}; + int i, reg_len = sizeof(stack_regs); + + for (i = 0 ; i < reg_len ; i++) { + if (bpf_reg == stack_regs[i]) + return true; + } + return false; } -static inline void emit_swap16(u8 r_dst __maybe_unused, - u8 r_src __maybe_unused, - struct jit_ctx *ctx __maybe_unused) +static inline void emit_a32_mov_i(const u8 dst, const u32 val, + bool dstk, struct jit_ctx *ctx) { -#ifdef __LITTLE_ENDIAN - emit(ARM_REV16(r_dst, r_src), ctx); -#endif + const u8 *tmp = bpf2a32[TMP_REG_1]; + + if (dstk) { + emit_mov_i(tmp[1], val, ctx); + emit(ARM_STR_I(tmp[1], ARM_SP, STACK_VAR(dst)), ctx); + } else { + emit_mov_i(dst, val, ctx); + } } -#endif /* __LINUX_ARM_ARCH__ < 6 */ +/* Sign extended move */ +static inline void emit_a32_mov_i64(const bool is64, const u8 dst[], + const u32 val, bool dstk, + struct jit_ctx *ctx) { + u32 hi = 0; + if (is64 && (val & (1<<31))) + hi = (u32)~0; + emit_a32_mov_i(dst_lo, val, dstk, ctx); + emit_a32_mov_i(dst_hi, hi, dstk, ctx); +} -/* Compute the immediate value for a PC-relative branch. */ -static inline u32 b_imm(unsigned tgt, struct jit_ctx *ctx) -{ - u32 imm; +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); +} - if (ctx->target == NULL) - return 0; - /* - * BPF allows only forward jumps and the offset of the target is - * still the one computed during the first pass. +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 */ - imm = ctx->offsets[tgt] + ctx->prologue_bytes - (ctx->idx * 4 + 8); + 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); +} - return imm >> 2; +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; + } } -#define OP_IMM3(op, r1, r2, imm_val, ctx) \ - do { \ - imm12 = imm8m(imm_val); \ - if (imm12 < 0) { \ - emit_mov_i_no8m(r_scratch, imm_val, ctx); \ - emit(op ## _R((r1), (r2), r_scratch), ctx); \ - } else { \ - emit(op ## _I((r1), (r2), imm12), ctx); \ - } \ - } while (0) - -static inline void emit_err_ret(u8 cond, struct jit_ctx *ctx) -{ - if (ctx->ret0_fp_idx >= 0) { - _emit(cond, ARM_B(b_imm(ctx->ret0_fp_idx, ctx)), ctx); - /* NOP to keep the size constant between passes */ - emit(ARM_MOV_R(ARM_R0, ARM_R0), ctx); +/* ALU operation (32 bit) + * dst = dst (op) src + */ +static inline void emit_a32_alu_r(const u8 dst, const u8 src, + bool dstk, bool sstk, + struct jit_ctx *ctx, const bool is64, + const bool hi, const u8 op) { + const u8 *tmp = bpf2a32[TMP_REG_1]; + u8 rn = sstk ? tmp[1] : src; + + if (sstk) + emit(ARM_LDR_I(rn, ARM_SP, STACK_VAR(src)), ctx); + + /* ALU operation */ + if (dstk) { + emit(ARM_LDR_I(tmp[0], ARM_SP, STACK_VAR(dst)), ctx); + emit_alu_r(tmp[0], rn, is64, hi, op, ctx); + emit(ARM_STR_I(tmp[0], ARM_SP, STACK_VAR(dst)), ctx); } else { - _emit(cond, ARM_MOV_I(ARM_R0, 0), ctx); - _emit(cond, ARM_B(b_imm(ctx->skf->len, ctx)), ctx); + emit_alu_r(dst, rn, is64, hi, op, 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); +/* ALU operation (64 bit) */ +static inline void emit_a32_alu_r64(const bool is64, const u8 dst[], + const u8 src[], bool dstk, + bool sstk, struct jit_ctx *ctx, + const u8 op) { + emit_a32_alu_r(dst_lo, src_lo, dstk, sstk, ctx, is64, false, op); + if (is64) + emit_a32_alu_r(dst_hi, src_hi, dstk, sstk, ctx, is64, true, op); + else + emit_a32_mov_i(dst_hi, 0, dstk, ctx); +} - if (elf_hwcap & HWCAP_THUMB) - emit(ARM_BX(tgt_reg), ctx); +/* dst = imm (4 bytes)*/ +static inline void emit_a32_mov_r(const u8 dst, const u8 src, + bool dstk, bool sstk, + struct jit_ctx *ctx) { + const u8 *tmp = bpf2a32[TMP_REG_1]; + u8 rt = sstk ? tmp[0] : src; + + if (sstk) + emit(ARM_LDR_I(tmp[0], ARM_SP, STACK_VAR(src)), ctx); + if (dstk) + emit(ARM_STR_I(rt, ARM_SP, STACK_VAR(dst)), ctx); else - emit(ARM_MOV_R(ARM_PC, tgt_reg), ctx); -#else - emit(ARM_BLX_R(tgt_reg), ctx); -#endif + emit(ARM_MOV_R(dst, rt), ctx); } -static inline void emit_udivmod(u8 rd, u8 rm, u8 rn, struct jit_ctx *ctx, - int bpf_op) -{ -#if __LINUX_ARM_ARCH__ == 7 - if (elf_hwcap & HWCAP_IDIVA) { - if (bpf_op == BPF_DIV) - emit(ARM_UDIV(rd, rm, rn), ctx); - else { - emit(ARM_UDIV(ARM_R3, rm, rn), ctx); - emit(ARM_MLS(rd, rn, ARM_R3, rm), ctx); - } - return; +/* dst = src */ +static inline void emit_a32_mov_r64(const bool is64, const u8 dst[], + const u8 src[], bool dstk, + bool sstk, struct jit_ctx *ctx) { + emit_a32_mov_r(dst_lo, src_lo, dstk, sstk, ctx); + if (is64) { + /* complete 8 byte move */ + emit_a32_mov_r(dst_hi, src_hi, dstk, sstk, ctx); + } else { + /* Zero out high 4 bytes */ + emit_a32_mov_i(dst_hi, 0, dstk, ctx); } -#endif +} - /* - * For BPF_ALU | BPF_DIV | BPF_K instructions, rm is ARM_R4 - * (r_A) and rn is ARM_R0 (r_scratch) so load rn first into - * ARM_R1 to avoid accidentally overwriting ARM_R0 with rm - * before using it as a source for ARM_R1. - * - * For BPF_ALU | BPF_DIV | BPF_X rm is ARM_R4 (r_A) and rn is - * ARM_R5 (r_X) so there is no particular register overlap - * issues. - */ - if (rn != ARM_R1) - emit(ARM_MOV_R(ARM_R1, rn), ctx); - if (rm != ARM_R0) - emit(ARM_MOV_R(ARM_R0, rm), ctx); +/* Shift operations */ +static inline void emit_a32_alu_i(const u8 dst, const u32 val, bool dstk, + struct jit_ctx *ctx, const u8 op) { + const u8 *tmp = bpf2a32[TMP_REG_1]; + u8 rd = dstk ? tmp[0] : dst; + + if (dstk) + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst)), 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; + } + if (dstk) + emit(ARM_STR_I(rd, ARM_SP, STACK_VAR(dst)), ctx); +} + +/* dst = ~dst (64 bit) */ +static inline void emit_a32_neg64(const u8 dst[], bool dstk, + struct jit_ctx *ctx){ + const u8 *tmp = bpf2a32[TMP_REG_1]; + u8 rd = dstk ? tmp[1] : dst[1]; + u8 rm = dstk ? tmp[0] : dst[0]; + + /* Setup Operand */ + if (dstk) { + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx); + } + + /* Do Negate Operation */ + emit(ARM_RSBS_I(rd, rd, 0), ctx); + emit(ARM_RSC_I(rm, rm, 0), ctx); + + if (dstk) { + emit(ARM_STR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_STR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx); + } +} + +/* dst = dst << src */ +static inline void emit_a32_lsh_r64(const u8 dst[], const u8 src[], bool dstk, + bool sstk, struct jit_ctx *ctx) { + const u8 *tmp = bpf2a32[TMP_REG_1]; + const u8 *tmp2 = bpf2a32[TMP_REG_2]; + + /* Setup Operands */ + u8 rt = sstk ? tmp2[1] : src_lo; + u8 rd = dstk ? tmp[1] : dst_lo; + u8 rm = dstk ? tmp[0] : dst_hi; + + if (sstk) + emit(ARM_LDR_I(rt, ARM_SP, STACK_VAR(src_lo)), ctx); + if (dstk) { + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx); + } + + /* Do LSH operation */ + emit(ARM_SUB_I(ARM_IP, rt, 32), ctx); + emit(ARM_RSB_I(tmp2[0], rt, 32), ctx); + /* As we are using ARM_LR */ ctx->seen |= SEEN_CALL; - emit_mov_i(ARM_R3, bpf_op == BPF_DIV ? (u32)jit_udiv : (u32)jit_mod, - ctx); - emit_blx_r(ARM_R3, ctx); + emit(ARM_MOV_SR(ARM_LR, rm, SRTYPE_ASL, rt), ctx); + emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd, SRTYPE_ASL, ARM_IP), ctx); + emit(ARM_ORR_SR(ARM_IP, ARM_LR, rd, SRTYPE_LSR, tmp2[0]), ctx); + emit(ARM_MOV_SR(ARM_LR, rd, SRTYPE_ASL, rt), ctx); + + if (dstk) { + emit(ARM_STR_I(ARM_LR, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_STR_I(ARM_IP, ARM_SP, STACK_VAR(dst_hi)), ctx); + } else { + emit(ARM_MOV_R(rd, ARM_LR), ctx); + emit(ARM_MOV_R(rm, ARM_IP), ctx); + } +} - if (rd != ARM_R0) - emit(ARM_MOV_R(rd, ARM_R0), ctx); +/* dst = dst >> src (signed)*/ +static inline void emit_a32_arsh_r64(const u8 dst[], const u8 src[], bool dstk, + bool sstk, struct jit_ctx *ctx) { + const u8 *tmp = bpf2a32[TMP_REG_1]; + const u8 *tmp2 = bpf2a32[TMP_REG_2]; + /* Setup Operands */ + u8 rt = sstk ? tmp2[1] : src_lo; + u8 rd = dstk ? tmp[1] : dst_lo; + u8 rm = dstk ? tmp[0] : dst_hi; + + if (sstk) + emit(ARM_LDR_I(rt, ARM_SP, STACK_VAR(src_lo)), ctx); + if (dstk) { + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx); + } + + /* Do the ARSH operation */ + emit(ARM_RSB_I(ARM_IP, rt, 32), ctx); + emit(ARM_SUBS_I(tmp2[0], rt, 32), ctx); + /* As we are using ARM_LR */ + ctx->seen |= SEEN_CALL; + emit(ARM_MOV_SR(ARM_LR, rd, SRTYPE_LSR, rt), ctx); + emit(ARM_ORR_SR(ARM_LR, ARM_LR, rm, SRTYPE_ASL, ARM_IP), ctx); + _emit(ARM_COND_MI, ARM_B(0), ctx); + emit(ARM_ORR_SR(ARM_LR, ARM_LR, rm, SRTYPE_ASR, tmp2[0]), ctx); + emit(ARM_MOV_SR(ARM_IP, rm, SRTYPE_ASR, rt), ctx); + if (dstk) { + emit(ARM_STR_I(ARM_LR, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_STR_I(ARM_IP, ARM_SP, STACK_VAR(dst_hi)), ctx); + } else { + emit(ARM_MOV_R(rd, ARM_LR), ctx); + emit(ARM_MOV_R(rm, ARM_IP), ctx); + } +} + +/* dst = dst >> src */ +static inline void emit_a32_lsr_r64(const u8 dst[], const u8 src[], bool dstk, + bool sstk, struct jit_ctx *ctx) { + const u8 *tmp = bpf2a32[TMP_REG_1]; + const u8 *tmp2 = bpf2a32[TMP_REG_2]; + /* Setup Operands */ + u8 rt = sstk ? tmp2[1] : src_lo; + u8 rd = dstk ? tmp[1] : dst_lo; + u8 rm = dstk ? tmp[0] : dst_hi; + + if (sstk) + emit(ARM_LDR_I(rt, ARM_SP, STACK_VAR(src_lo)), ctx); + if (dstk) { + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx); + } + + /* Do LSH operation */ + emit(ARM_RSB_I(ARM_IP, rt, 32), ctx); + emit(ARM_SUBS_I(tmp2[0], rt, 32), ctx); + /* As we are using ARM_LR */ + ctx->seen |= SEEN_CALL; + emit(ARM_MOV_SR(ARM_LR, rd, SRTYPE_LSR, rt), ctx); + emit(ARM_ORR_SR(ARM_LR, ARM_LR, rm, SRTYPE_ASL, ARM_IP), ctx); + emit(ARM_ORR_SR(ARM_LR, ARM_LR, rm, SRTYPE_LSR, tmp2[0]), ctx); + emit(ARM_MOV_SR(ARM_IP, rm, SRTYPE_LSR, rt), ctx); + if (dstk) { + emit(ARM_STR_I(ARM_LR, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_STR_I(ARM_IP, ARM_SP, STACK_VAR(dst_hi)), ctx); + } else { + emit(ARM_MOV_R(rd, ARM_LR), ctx); + emit(ARM_MOV_R(rm, ARM_IP), ctx); + } } -static inline void update_on_xread(struct jit_ctx *ctx) +/* dst = dst << val */ +static inline void emit_a32_lsh_i64(const u8 dst[], bool dstk, + const u32 val, struct jit_ctx *ctx){ + const u8 *tmp = bpf2a32[TMP_REG_1]; + const u8 *tmp2 = bpf2a32[TMP_REG_2]; + /* Setup operands */ + u8 rd = dstk ? tmp[1] : dst_lo; + u8 rm = dstk ? tmp[0] : dst_hi; + + if (dstk) { + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx); + } + + /* Do LSH operation */ + if (val < 32) { + emit(ARM_MOV_SI(tmp2[0], rm, SRTYPE_ASL, val), ctx); + emit(ARM_ORR_SI(rm, tmp2[0], rd, SRTYPE_LSR, 32 - val), ctx); + emit(ARM_MOV_SI(rd, rd, SRTYPE_ASL, val), ctx); + } else { + if (val == 32) + emit(ARM_MOV_R(rm, rd), ctx); + else + emit(ARM_MOV_SI(rm, rd, SRTYPE_ASL, val - 32), ctx); + emit(ARM_EOR_R(rd, rd, rd), ctx); + } + + if (dstk) { + emit(ARM_STR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_STR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx); + } +} + +/* dst = dst >> val */ +static inline void emit_a32_lsr_i64(const u8 dst[], bool dstk, + const u32 val, struct jit_ctx *ctx) { + const u8 *tmp = bpf2a32[TMP_REG_1]; + const u8 *tmp2 = bpf2a32[TMP_REG_2]; + /* Setup operands */ + u8 rd = dstk ? tmp[1] : dst_lo; + u8 rm = dstk ? tmp[0] : dst_hi; + + if (dstk) { + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx); + } + + /* Do LSR operation */ + if (val < 32) { + emit(ARM_MOV_SI(tmp2[1], rd, SRTYPE_LSR, val), ctx); + emit(ARM_ORR_SI(rd, tmp2[1], rm, SRTYPE_ASL, 32 - val), ctx); + emit(ARM_MOV_SI(rm, rm, SRTYPE_LSR, val), ctx); + } else if (val == 32) { + emit(ARM_MOV_R(rd, rm), ctx); + emit(ARM_MOV_I(rm, 0), ctx); + } else { + emit(ARM_MOV_SI(rd, rm, SRTYPE_LSR, val - 32), ctx); + emit(ARM_MOV_I(rm, 0), ctx); + } + + if (dstk) { + emit(ARM_STR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_STR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx); + } +} + +/* dst = dst >> val (signed) */ +static inline void emit_a32_arsh_i64(const u8 dst[], bool dstk, + const u32 val, struct jit_ctx *ctx){ + const u8 *tmp = bpf2a32[TMP_REG_1]; + const u8 *tmp2 = bpf2a32[TMP_REG_2]; + /* Setup operands */ + u8 rd = dstk ? tmp[1] : dst_lo; + u8 rm = dstk ? tmp[0] : dst_hi; + + if (dstk) { + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx); + } + + /* Do ARSH operation */ + if (val < 32) { + emit(ARM_MOV_SI(tmp2[1], rd, SRTYPE_LSR, val), ctx); + emit(ARM_ORR_SI(rd, tmp2[1], rm, SRTYPE_ASL, 32 - val), ctx); + emit(ARM_MOV_SI(rm, rm, SRTYPE_ASR, val), ctx); + } else if (val == 32) { + emit(ARM_MOV_R(rd, rm), ctx); + emit(ARM_MOV_SI(rm, rm, SRTYPE_ASR, 31), ctx); + } else { + emit(ARM_MOV_SI(rd, rm, SRTYPE_ASR, val - 32), ctx); + emit(ARM_MOV_SI(rm, rm, SRTYPE_ASR, 31), ctx); + } + + if (dstk) { + emit(ARM_STR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_STR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx); + } +} + +static inline void emit_a32_mul_r64(const u8 dst[], const u8 src[], bool dstk, + bool sstk, struct jit_ctx *ctx) { + const u8 *tmp = bpf2a32[TMP_REG_1]; + const u8 *tmp2 = bpf2a32[TMP_REG_2]; + /* Setup operands for multiplication */ + u8 rd = dstk ? tmp[1] : dst_lo; + u8 rm = dstk ? tmp[0] : dst_hi; + u8 rt = sstk ? tmp2[1] : src_lo; + u8 rn = sstk ? tmp2[0] : src_hi; + + if (dstk) { + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx); + } + if (sstk) { + emit(ARM_LDR_I(rt, ARM_SP, STACK_VAR(src_lo)), ctx); + emit(ARM_LDR_I(rn, ARM_SP, STACK_VAR(src_hi)), ctx); + } + + /* Do Multiplication */ + emit(ARM_MUL(ARM_IP, rd, rn), ctx); + emit(ARM_MUL(ARM_LR, rm, rt), ctx); + /* As we are using ARM_LR */ + ctx->seen |= SEEN_CALL; + emit(ARM_ADD_R(ARM_LR, ARM_IP, ARM_LR), ctx); + + emit(ARM_UMULL(ARM_IP, rm, rd, rt), ctx); + emit(ARM_ADD_R(rm, ARM_LR, rm), ctx); + if (dstk) { + emit(ARM_STR_I(ARM_IP, ARM_SP, STACK_VAR(dst_lo)), ctx); + emit(ARM_STR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx); + } else { + emit(ARM_MOV_R(rd, ARM_IP), ctx); + } +} + +/* *(size *)(dst + off) = src */ +static inline void emit_str_r(const u8 dst, const u8 src, bool dstk, + const s32 off, struct jit_ctx *ctx, const u8 sz){ + const u8 *tmp = bpf2a32[TMP_REG_1]; + u8 rd = dstk ? tmp[1] : dst; + + if (dstk) + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst)), ctx); + if (off) { + emit_a32_mov_i(tmp[0], off, false, ctx); + emit(ARM_ADD_R(tmp[0], rd, tmp[0]), ctx); + rd = tmp[0]; + } |