diff options
Diffstat (limited to 'arch/mips/net')
| -rw-r--r-- | arch/mips/net/Makefile | 4 | ||||
| -rw-r--r-- | arch/mips/net/bpf_jit.c | 1299 | ||||
| -rw-r--r-- | arch/mips/net/bpf_jit.h | 84 | ||||
| -rw-r--r-- | arch/mips/net/bpf_jit_asm.S | 285 | ||||
| -rw-r--r-- | arch/mips/net/ebpf_jit.c | 1849 |
5 files changed, 3521 insertions, 0 deletions
diff --git a/arch/mips/net/Makefile b/arch/mips/net/Makefile new file mode 100644 index 000000000..47d678416 --- /dev/null +++ b/arch/mips/net/Makefile @@ -0,0 +1,4 @@ +# MIPS networking code + +obj-$(CONFIG_MIPS_CBPF_JIT) += bpf_jit.o bpf_jit_asm.o +obj-$(CONFIG_MIPS_EBPF_JIT) += ebpf_jit.o diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c new file mode 100644 index 000000000..43e6597c7 --- /dev/null +++ b/arch/mips/net/bpf_jit.c @@ -0,0 +1,1299 @@ +/* + * Just-In-Time compiler for BPF filters on MIPS + * + * Copyright (c) 2014 Imagination Technologies Ltd. + * Author: Markos Chandras <markos.chandras@imgtec.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/bitops.h> +#include <linux/compiler.h> +#include <linux/errno.h> +#include <linux/filter.h> +#include <linux/if_vlan.h> +#include <linux/moduleloader.h> +#include <linux/netdevice.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <asm/asm.h> +#include <asm/bitops.h> +#include <asm/cacheflush.h> +#include <asm/cpu-features.h> +#include <asm/uasm.h> + +#include "bpf_jit.h" + +/* ABI + * r_skb_hl SKB header length + * r_data SKB data pointer + * r_off Offset + * r_A BPF register A + * r_X BPF register X + * r_skb *skb + * r_M *scratch memory + * r_skb_len SKB length + * + * On entry (*bpf_func)(*skb, *filter) + * a0 = MIPS_R_A0 = skb; + * a1 = MIPS_R_A1 = filter; + * + * Stack + * ... + * M[15] + * M[14] + * M[13] + * ... + * M[0] <-- r_M + * saved reg k-1 + * saved reg k-2 + * ... + * saved reg 0 <-- r_sp + * <no argument area> + * + * Packet layout + * + * <--------------------- len ------------------------> + * <--skb-len(r_skb_hl)-->< ----- skb->data_len ------> + * ---------------------------------------------------- + * | skb->data | + * ---------------------------------------------------- + */ + +#define ptr typeof(unsigned long) + +#define SCRATCH_OFF(k) (4 * (k)) + +/* JIT flags */ +#define SEEN_CALL (1 << BPF_MEMWORDS) +#define SEEN_SREG_SFT (BPF_MEMWORDS + 1) +#define SEEN_SREG_BASE (1 << SEEN_SREG_SFT) +#define SEEN_SREG(x) (SEEN_SREG_BASE << (x)) +#define SEEN_OFF SEEN_SREG(2) +#define SEEN_A SEEN_SREG(3) +#define SEEN_X SEEN_SREG(4) +#define SEEN_SKB SEEN_SREG(5) +#define SEEN_MEM SEEN_SREG(6) +/* SEEN_SK_DATA also implies skb_hl an skb_len */ +#define SEEN_SKB_DATA (SEEN_SREG(7) | SEEN_SREG(1) | SEEN_SREG(0)) + +/* Arguments used by JIT */ +#define ARGS_USED_BY_JIT 2 /* only applicable to 64-bit */ + +#define SBIT(x) (1 << (x)) /* Signed version of BIT() */ + +/** + * struct jit_ctx - JIT context + * @skf: The sk_filter + * @prologue_bytes: Number of bytes for prologue + * @idx: Instruction index + * @flags: JIT flags + * @offsets: Instruction offsets + * @target: Memory location for the compiled filter + */ +struct jit_ctx { + const struct bpf_prog *skf; + unsigned int prologue_bytes; + u32 idx; + u32 flags; + u32 *offsets; + u32 *target; +}; + + +static inline int optimize_div(u32 *k) +{ + /* power of 2 divides can be implemented with right shift */ + if (!(*k & (*k-1))) { + *k = ilog2(*k); + return 1; + } + + return 0; +} + +static inline void emit_jit_reg_move(ptr dst, ptr src, struct jit_ctx *ctx); + +/* Simply emit the instruction if the JIT memory space has been allocated */ +#define emit_instr(ctx, func, ...) \ +do { \ + if ((ctx)->target != NULL) { \ + u32 *p = &(ctx)->target[ctx->idx]; \ + uasm_i_##func(&p, ##__VA_ARGS__); \ + } \ + (ctx)->idx++; \ +} while (0) + +/* + * Similar to emit_instr but it must be used when we need to emit + * 32-bit or 64-bit instructions + */ +#define emit_long_instr(ctx, func, ...) \ +do { \ + if ((ctx)->target != NULL) { \ + u32 *p = &(ctx)->target[ctx->idx]; \ + UASM_i_##func(&p, ##__VA_ARGS__); \ + } \ + (ctx)->idx++; \ +} while (0) + +/* Determine if immediate is within the 16-bit signed range */ +static inline bool is_range16(s32 imm) +{ + return !(imm >= SBIT(15) || imm < -SBIT(15)); +} + +static inline void emit_addu(unsigned int dst, unsigned int src1, + unsigned int src2, struct jit_ctx *ctx) +{ + emit_instr(ctx, addu, dst, src1, src2); +} + +static inline void emit_nop(struct jit_ctx *ctx) +{ + emit_instr(ctx, nop); +} + +/* Load a u32 immediate to a register */ +static inline void emit_load_imm(unsigned int dst, u32 imm, struct jit_ctx *ctx) +{ + if (ctx->target != NULL) { + /* addiu can only handle s16 */ + if (!is_range16(imm)) { + u32 *p = &ctx->target[ctx->idx]; + uasm_i_lui(&p, r_tmp_imm, (s32)imm >> 16); + p = &ctx->target[ctx->idx + 1]; + uasm_i_ori(&p, dst, r_tmp_imm, imm & 0xffff); + } else { + u32 *p = &ctx->target[ctx->idx]; + uasm_i_addiu(&p, dst, r_zero, imm); + } + } + ctx->idx++; + + if (!is_range16(imm)) + ctx->idx++; +} + +static inline void emit_or(unsigned int dst, unsigned int src1, + unsigned int src2, struct jit_ctx *ctx) +{ + emit_instr(ctx, or, dst, src1, src2); +} + +static inline void emit_ori(unsigned int dst, unsigned src, u32 imm, + struct jit_ctx *ctx) +{ + if (imm >= BIT(16)) { + emit_load_imm(r_tmp, imm, ctx); + emit_or(dst, src, r_tmp, ctx); + } else { + emit_instr(ctx, ori, dst, src, imm); + } +} + +static inline void emit_daddiu(unsigned int dst, unsigned int src, + int imm, struct jit_ctx *ctx) +{ + /* + * Only used for stack, so the imm is relatively small + * and it fits in 15-bits + */ + emit_instr(ctx, daddiu, dst, src, imm); +} + +static inline void emit_addiu(unsigned int dst, unsigned int src, + u32 imm, struct jit_ctx *ctx) +{ + if (!is_range16(imm)) { + emit_load_imm(r_tmp, imm, ctx); + emit_addu(dst, r_tmp, src, ctx); + } else { + emit_instr(ctx, addiu, dst, src, imm); + } +} + +static inline void emit_and(unsigned int dst, unsigned int src1, + unsigned int src2, struct jit_ctx *ctx) +{ + emit_instr(ctx, and, dst, src1, src2); +} + +static inline void emit_andi(unsigned int dst, unsigned int src, + u32 imm, struct jit_ctx *ctx) +{ + /* If imm does not fit in u16 then load it to register */ + if (imm >= BIT(16)) { + emit_load_imm(r_tmp, imm, ctx); + emit_and(dst, src, r_tmp, ctx); + } else { + emit_instr(ctx, andi, dst, src, imm); + } +} + +static inline void emit_xor(unsigned int dst, unsigned int src1, + unsigned int src2, struct jit_ctx *ctx) +{ + emit_instr(ctx, xor, dst, src1, src2); +} + +static inline void emit_xori(ptr dst, ptr src, u32 imm, struct jit_ctx *ctx) +{ + /* If imm does not fit in u16 then load it to register */ + if (imm >= BIT(16)) { + emit_load_imm(r_tmp, imm, ctx); + emit_xor(dst, src, r_tmp, ctx); + } else { + emit_instr(ctx, xori, dst, src, imm); + } +} + +static inline void emit_stack_offset(int offset, struct jit_ctx *ctx) +{ + emit_long_instr(ctx, ADDIU, r_sp, r_sp, offset); +} + +static inline void emit_subu(unsigned int dst, unsigned int src1, + unsigned int src2, struct jit_ctx *ctx) +{ + emit_instr(ctx, subu, dst, src1, src2); +} + +static inline void emit_neg(unsigned int reg, struct jit_ctx *ctx) +{ + emit_subu(reg, r_zero, reg, ctx); +} + +static inline void emit_sllv(unsigned int dst, unsigned int src, + unsigned int sa, struct jit_ctx *ctx) +{ + emit_instr(ctx, sllv, dst, src, sa); +} + +static inline void emit_sll(unsigned int dst, unsigned int src, + unsigned int sa, struct jit_ctx *ctx) +{ + /* sa is 5-bits long */ + if (sa >= BIT(5)) + /* Shifting >= 32 results in zero */ + emit_jit_reg_move(dst, r_zero, ctx); + else + emit_instr(ctx, sll, dst, src, sa); +} + +static inline void emit_srlv(unsigned int dst, unsigned int src, + unsigned int sa, struct jit_ctx *ctx) +{ + emit_instr(ctx, srlv, dst, src, sa); +} + +static inline void emit_srl(unsigned int dst, unsigned int src, + unsigned int sa, struct jit_ctx *ctx) +{ + /* sa is 5-bits long */ + if (sa >= BIT(5)) + /* Shifting >= 32 results in zero */ + emit_jit_reg_move(dst, r_zero, ctx); + else + emit_instr(ctx, srl, dst, src, sa); +} + +static inline void emit_slt(unsigned int dst, unsigned int src1, + unsigned int src2, struct jit_ctx *ctx) +{ + emit_instr(ctx, slt, dst, src1, src2); +} + +static inline void emit_sltu(unsigned int dst, unsigned int src1, + unsigned int src2, struct jit_ctx *ctx) +{ + emit_instr(ctx, sltu, dst, src1, src2); +} + +static inline void emit_sltiu(unsigned dst, unsigned int src, + unsigned int imm, struct jit_ctx *ctx) +{ + /* 16 bit immediate */ + if (!is_range16((s32)imm)) { + emit_load_imm(r_tmp, imm, ctx); + emit_sltu(dst, src, r_tmp, ctx); + } else { + emit_instr(ctx, sltiu, dst, src, imm); + } + +} + +/* Store register on the stack */ +static inline void emit_store_stack_reg(ptr reg, ptr base, + unsigned int offset, + struct jit_ctx *ctx) +{ + emit_long_instr(ctx, SW, reg, offset, base); +} + +static inline void emit_store(ptr reg, ptr base, unsigned int offset, + struct jit_ctx *ctx) +{ + emit_instr(ctx, sw, reg, offset, base); +} + +static inline void emit_load_stack_reg(ptr reg, ptr base, + unsigned int offset, + struct jit_ctx *ctx) +{ + emit_long_instr(ctx, LW, reg, offset, base); +} + +static inline void emit_load(unsigned int reg, unsigned int base, + unsigned int offset, struct jit_ctx *ctx) +{ + emit_instr(ctx, lw, reg, offset, base); +} + +static inline void emit_load_byte(unsigned int reg, unsigned int base, + unsigned int offset, struct jit_ctx *ctx) +{ + emit_instr(ctx, lb, reg, offset, base); +} + +static inline void emit_half_load(unsigned int reg, unsigned int base, + unsigned int offset, struct jit_ctx *ctx) +{ + emit_instr(ctx, lh, reg, offset, base); +} + +static inline void emit_half_load_unsigned(unsigned int reg, unsigned int base, + unsigned int offset, struct jit_ctx *ctx) +{ + emit_instr(ctx, lhu, reg, offset, base); +} + +static inline void emit_mul(unsigned int dst, unsigned int src1, + unsigned int src2, struct jit_ctx *ctx) +{ + emit_instr(ctx, mul, dst, src1, src2); +} + +static inline void emit_div(unsigned int dst, unsigned int src, + struct jit_ctx *ctx) +{ + if (ctx->target != NULL) { + u32 *p = &ctx->target[ctx->idx]; + uasm_i_divu(&p, dst, src); + p = &ctx->target[ctx->idx + 1]; + uasm_i_mflo(&p, dst); + } + ctx->idx += 2; /* 2 insts */ +} + +static inline void emit_mod(unsigned int dst, unsigned int src, + struct jit_ctx *ctx) +{ + if (ctx->target != NULL) { + u32 *p = &ctx->target[ctx->idx]; + uasm_i_divu(&p, dst, src); + p = &ctx->target[ctx->idx + 1]; + uasm_i_mfhi(&p, dst); + } + ctx->idx += 2; /* 2 insts */ +} + +static inline void emit_dsll(unsigned int dst, unsigned int src, + unsigned int sa, struct jit_ctx *ctx) +{ + emit_instr(ctx, dsll, dst, src, sa); +} + +static inline void emit_dsrl32(unsigned int dst, unsigned int src, + unsigned int sa, struct jit_ctx *ctx) +{ + emit_instr(ctx, dsrl32, dst, src, sa); +} + +static inline void emit_wsbh(unsigned int dst, unsigned int src, + struct jit_ctx *ctx) +{ + emit_instr(ctx, wsbh, dst, src); +} + +/* load pointer to register */ +static inline void emit_load_ptr(unsigned int dst, unsigned int src, + int imm, struct jit_ctx *ctx) +{ + /* src contains the base addr of the 32/64-pointer */ + emit_long_instr(ctx, LW, dst, imm, src); +} + +/* load a function pointer to register */ +static inline void emit_load_func(unsigned int reg, ptr imm, + struct jit_ctx *ctx) +{ + if (IS_ENABLED(CONFIG_64BIT)) { + /* At this point imm is always 64-bit */ + emit_load_imm(r_tmp, (u64)imm >> 32, ctx); + emit_dsll(r_tmp_imm, r_tmp, 16, ctx); /* left shift by 16 */ + emit_ori(r_tmp, r_tmp_imm, (imm >> 16) & 0xffff, ctx); + emit_dsll(r_tmp_imm, r_tmp, 16, ctx); /* left shift by 16 */ + emit_ori(reg, r_tmp_imm, imm & 0xffff, ctx); + } else { + emit_load_imm(reg, imm, ctx); + } +} + +/* Move to real MIPS register */ +static inline void emit_reg_move(ptr dst, ptr src, struct jit_ctx *ctx) +{ + emit_long_instr(ctx, ADDU, dst, src, r_zero); +} + +/* Move to JIT (32-bit) register */ +static inline void emit_jit_reg_move(ptr dst, ptr src, struct jit_ctx *ctx) +{ + emit_addu(dst, src, r_zero, ctx); +} + +/* Compute the immediate value for PC-relative branches. */ +static inline u32 b_imm(unsigned int tgt, struct jit_ctx *ctx) +{ + if (ctx->target == NULL) + return 0; + + /* + * We want a pc-relative branch. We only do forward branches + * so tgt is always after pc. tgt is the instruction offset + * we want to jump to. + + * Branch on MIPS: + * I: target_offset <- sign_extend(offset) + * I+1: PC += target_offset (delay slot) + * + * ctx->idx currently points to the branch instruction + * but the offset is added to the delay slot so we need + * to subtract 4. + */ + return ctx->offsets[tgt] - + (ctx->idx * 4 - ctx->prologue_bytes) - 4; +} + +static inline void emit_bcond(int cond, unsigned int reg1, unsigned int reg2, + unsigned int imm, struct jit_ctx *ctx) +{ + if (ctx->target != NULL) { + u32 *p = &ctx->target[ctx->idx]; + + switch (cond) { + case MIPS_COND_EQ: + uasm_i_beq(&p, reg1, reg2, imm); + break; + case MIPS_COND_NE: + uasm_i_bne(&p, reg1, reg2, imm); + break; + case MIPS_COND_ALL: + uasm_i_b(&p, imm); + break; + default: + pr_warn("%s: Unhandled branch conditional: %d\n", + __func__, cond); + } + } + ctx->idx++; +} + +static inline void emit_b(unsigned int imm, struct jit_ctx *ctx) +{ + emit_bcond(MIPS_COND_ALL, r_zero, r_zero, imm, ctx); +} + +static inline void emit_jalr(unsigned int link, unsigned int reg, + struct jit_ctx *ctx) +{ + emit_instr(ctx, jalr, link, reg); +} + +static inline void emit_jr(unsigned int reg, struct jit_ctx *ctx) +{ + emit_instr(ctx, jr, reg); +} + +static inline u16 align_sp(unsigned int num) +{ + /* Double word alignment for 32-bit, quadword for 64-bit */ + unsigned int align = IS_ENABLED(CONFIG_64BIT) ? 16 : 8; + num = (num + (align - 1)) & -align; + return num; +} + +static void save_bpf_jit_regs(struct jit_ctx *ctx, unsigned offset) +{ + int i = 0, real_off = 0; + u32 sflags, tmp_flags; + + /* Adjust the stack pointer */ + if (offset) + emit_stack_offset(-align_sp(offset), ctx); + + tmp_flags = sflags = ctx->flags >> SEEN_SREG_SFT; + /* sflags is essentially a bitmap */ + while (tmp_flags) { + if ((sflags >> i) & 0x1) { + emit_store_stack_reg(MIPS_R_S0 + i, r_sp, real_off, + ctx); + real_off += SZREG; + } + i++; + tmp_flags >>= 1; + } + + /* save return address */ + if (ctx->flags & SEEN_CALL) { + emit_store_stack_reg(r_ra, r_sp, real_off, ctx); + real_off += SZREG; + } + + /* Setup r_M leaving the alignment gap if necessary */ + if (ctx->flags & SEEN_MEM) { + if (real_off % (SZREG * 2)) + real_off += SZREG; + emit_long_instr(ctx, ADDIU, r_M, r_sp, real_off); + } +} + +static void restore_bpf_jit_regs(struct jit_ctx *ctx, + unsigned int offset) +{ + int i, real_off = 0; + u32 sflags, tmp_flags; + + tmp_flags = sflags = ctx->flags >> SEEN_SREG_SFT; + /* sflags is a bitmap */ + i = 0; + while (tmp_flags) { + if ((sflags >> i) & 0x1) { + emit_load_stack_reg(MIPS_R_S0 + i, r_sp, real_off, + ctx); + real_off += SZREG; + } + i++; + tmp_flags >>= 1; + } + + /* restore return address */ + if (ctx->flags & SEEN_CALL) + emit_load_stack_reg(r_ra, r_sp, real_off, ctx); + + /* Restore the sp and discard the scrach memory */ + if (offset) + emit_stack_offset(align_sp(offset), ctx); +} + +static unsigned int get_stack_depth(struct jit_ctx *ctx) +{ + int sp_off = 0; + + + /* How may s* regs do we need to preserved? */ + sp_off += hweight32(ctx->flags >> SEEN_SREG_SFT) * SZREG; + + if (ctx->flags & SEEN_MEM) + sp_off += 4 * BPF_MEMWORDS; /* BPF_MEMWORDS are 32-bit */ + + if (ctx->flags & SEEN_CALL) + sp_off += SZREG; /* Space for our ra register */ + + return sp_off; +} + +static void build_prologue(struct jit_ctx *ctx) +{ + int sp_off; + + /* Calculate the total offset for the stack pointer */ + sp_off = get_stack_depth(ctx); + save_bpf_jit_regs(ctx, sp_off); + + if (ctx->flags & SEEN_SKB) + emit_reg_move(r_skb, MIPS_R_A0, ctx); + + if (ctx->flags & SEEN_SKB_DATA) { + /* Load packet length */ + emit_load(r_skb_len, r_skb, offsetof(struct sk_buff, len), + ctx); + emit_load(r_tmp, r_skb, offsetof(struct sk_buff, data_len), + ctx); + /* Load the data pointer */ + emit_load_ptr(r_skb_data, r_skb, + offsetof(struct sk_buff, data), ctx); + /* Load the header length */ + emit_subu(r_skb_hl, r_skb_len, r_tmp, ctx); + } + + if (ctx->flags & SEEN_X) + emit_jit_reg_move(r_X, r_zero, ctx); + + /* + * Do not leak kernel data to userspace, we only need to clear + * r_A if it is ever used. In fact if it is never used, we + * will not save/restore it, so clearing it in this case would + * corrupt the state of the caller. + */ + if (bpf_needs_clear_a(&ctx->skf->insns[0]) && + (ctx->flags & SEEN_A)) + emit_jit_reg_move(r_A, r_zero, ctx); +} + +static void build_epilogue(struct jit_ctx *ctx) +{ + unsigned int sp_off; + + /* Calculate the total offset for the stack pointer */ + + sp_off = get_stack_depth(ctx); + restore_bpf_jit_regs(ctx, sp_off); + + /* Return */ + emit_jr(r_ra, ctx); + emit_nop(ctx); +} + +#define CHOOSE_LOAD_FUNC(K, func) \ + ((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative : func) : \ + func##_positive) + +static bool is_bad_offset(int b_off) +{ + return b_off > 0x1ffff || b_off < -0x20000; +} + +static int build_body(struct jit_ctx *ctx) +{ + const struct bpf_prog *prog = ctx->skf; + const struct sock_filter *inst; + unsigned int i, off, condt; + u32 k, b_off __maybe_unused; + u8 (*sk_load_func)(unsigned long *skb, int offset); + + for (i = 0; i < prog->len; i++) { + u16 code; + + inst = &(prog->insns[i]); + pr_debug("%s: code->0x%02x, jt->0x%x, jf->0x%x, k->0x%x\n", + __func__, inst->code, inst->jt, inst->jf, inst->k); + k = inst->k; + code = bpf_anc_helper(inst); + + if (ctx->target == NULL) + ctx->offsets[i] = ctx->idx * 4; + + switch (code) { + case BPF_LD | BPF_IMM: + /* A <- k ==> li r_A, k */ + ctx->flags |= SEEN_A; + emit_load_imm(r_A, k, ctx); + break; + case BPF_LD | BPF_W | BPF_LEN: + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4); + /* A <- len ==> lw r_A, offset(skb) */ + ctx->flags |= SEEN_SKB | SEEN_A; + off = offsetof(struct sk_buff, len); + emit_load(r_A, r_skb, off, ctx); + break; + case BPF_LD | BPF_MEM: + /* A <- M[k] ==> lw r_A, offset(M) */ + ctx->flags |= SEEN_MEM | SEEN_A; + emit_load(r_A, r_M, SCRATCH_OFF(k), ctx); + break; + case BPF_LD | BPF_W | BPF_ABS: + /* A <- P[k:4] */ + sk_load_func = CHOOSE_LOAD_FUNC(k, sk_load_word); + goto load; + case BPF_LD | BPF_H | BPF_ABS: + /* A <- P[k:2] */ + sk_load_func = CHOOSE_LOAD_FUNC(k, sk_load_half); + goto load; + case BPF_LD | BPF_B | BPF_ABS: + /* A <- P[k:1] */ + sk_load_func = CHOOSE_LOAD_FUNC(k, sk_load_byte); +load: + emit_load_imm(r_off, k, ctx); +load_common: + ctx->flags |= SEEN_CALL | SEEN_OFF | + SEEN_SKB | SEEN_A | SEEN_SKB_DATA; + + emit_load_func(r_s0, (ptr)sk_load_func, ctx); + emit_reg_move(MIPS_R_A0, r_skb, ctx); + emit_jalr(MIPS_R_RA, r_s0, ctx); + /* Load second argument to delay slot */ + emit_reg_move(MIPS_R_A1, r_off, ctx); + /* Check the error value */ + emit_bcond(MIPS_COND_EQ, r_ret, 0, b_imm(i + 1, ctx), + ctx); + /* Load return register on DS for failures */ + emit_reg_move(r_ret, r_zero, ctx); + /* Return with error */ + b_off = b_imm(prog->len, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + emit_b(b_off, ctx); + emit_nop(ctx); + break; + case BPF_LD | BPF_W | BPF_IND: + /* A <- P[X + k:4] */ + sk_load_func = sk_load_word; + goto load_ind; + case BPF_LD | BPF_H | BPF_IND: + /* A <- P[X + k:2] */ + sk_load_func = sk_load_half; + goto load_ind; + case BPF_LD | BPF_B | BPF_IND: + /* A <- P[X + k:1] */ + sk_load_func = sk_load_byte; +load_ind: + ctx->flags |= SEEN_OFF | SEEN_X; + emit_addiu(r_off, r_X, k, ctx); + goto load_common; + case BPF_LDX | BPF_IMM: + /* X <- k */ + ctx->flags |= SEEN_X; + emit_load_imm(r_X, k, ctx); + break; + case BPF_LDX | BPF_MEM: + /* X <- M[k] */ + ctx->flags |= SEEN_X | SEEN_MEM; + emit_load(r_X, r_M, SCRATCH_OFF(k), ctx); + break; + case BPF_LDX | BPF_W | BPF_LEN: + /* X <- len */ + ctx->flags |= SEEN_X | SEEN_SKB; + off = offsetof(struct sk_buff, len); + emit_load(r_X, r_skb, off, ctx); + break; + case BPF_LDX | BPF_B | BPF_MSH: + /* X <- 4 * (P[k:1] & 0xf) */ + ctx->flags |= SEEN_X | SEEN_CALL | SEEN_SKB; + /* Load offset to a1 */ + emit_load_func(r_s0, (ptr)sk_load_byte, ctx); + /* + * This may emit two instructions so it may not fit + * in the delay slot. So use a0 in the delay slot. + */ + emit_load_imm(MIPS_R_A1, k, ctx); + emit_jalr(MIPS_R_RA, r_s0, ctx); + emit_reg_move(MIPS_R_A0, r_skb, ctx); /* delay slot */ + /* Check the error value */ + b_off = b_imm(prog->len, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + emit_bcond(MIPS_COND_NE, r_ret, 0, b_off, ctx); + emit_reg_move(r_ret, r_zero, ctx); + /* We are good */ + /* X <- P[1:K] & 0xf */ + emit_andi(r_X, r_A, 0xf, ctx); + /* X << 2 */ + emit_b(b_imm(i + 1, ctx), ctx); + emit_sll(r_X, r_X, 2, ctx); /* delay slot */ + break; + case BPF_ST: + /* M[k] <- A */ + ctx->flags |= SEEN_MEM | SEEN_A; + emit_store(r_A, r_M, SCRATCH_OFF(k), ctx); + break; + case BPF_STX: + /* M[k] <- X */ + ctx->flags |= SEEN_MEM | SEEN_X; + emit_store(r_X, r_M, SCRATCH_OFF(k), ctx); + break; + case BPF_ALU | BPF_ADD | BPF_K: + /* A += K */ + ctx->flags |= SEEN_A; + emit_addiu(r_A, r_A, k, ctx); + break; + case BPF_ALU | BPF_ADD | BPF_X: + /* A += X */ + ctx->flags |= SEEN_A | SEEN_X; + emit_addu(r_A, r_A, r_X, ctx); + break; + case BPF_ALU | BPF_SUB | BPF_K: + /* A -= K */ + ctx->flags |= SEEN_A; + emit_addiu(r_A, r_A, -k, ctx); + break; + case BPF_ALU | BPF_SUB | BPF_X: + /* A -= X */ + ctx->flags |= SEEN_A | SEEN_X; + emit_subu(r_A, r_A, r_X, ctx); + break; + case BPF_ALU | BPF_MUL | BPF_K: + /* A *= K */ + /* Load K to scratch register before MUL */ + ctx->flags |= SEEN_A; + emit_load_imm(r_s0, k, ctx); + emit_mul(r_A, r_A, r_s0, ctx); + break; + case BPF_ALU | BPF_MUL | BPF_X: + /* A *= X */ + ctx->flags |= SEEN_A | SEEN_X; + emit_mul(r_A, r_A, r_X, ctx); + break; + case BPF_ALU | BPF_DIV | BPF_K: + /* A /= k */ + if (k == 1) + break; + if (optimize_div(&k)) { + ctx->flags |= SEEN_A; + emit_srl(r_A, r_A, k, ctx); + break; + } + ctx->flags |= SEEN_A; + emit_load_imm(r_s0, k, ctx); + emit_div(r_A, r_s0, ctx); + break; + case BPF_ALU | BPF_MOD | BPF_K: + /* A %= k */ + if (k == 1) { + ctx->flags |= SEEN_A; + emit_jit_reg_move(r_A, r_zero, ctx); + } else { + ctx->flags |= SEEN_A; + emit_load_imm(r_s0, k, ctx); + emit_mod(r_A, r_s0, ctx); + } + break; + case BPF_ALU | BPF_DIV | BPF_X: + /* A /= X */ + ctx->flags |= SEEN_X | SEEN_A; + /* Check if r_X is zero */ + b_off = b_imm(prog->len, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + emit_bcond(MIPS_COND_EQ, r_X, r_zero, b_off, ctx); + emit_load_imm(r_ret, 0, ctx); /* delay slot */ + emit_div(r_A, r_X, ctx); + break; + case BPF_ALU | BPF_MOD | BPF_X: + /* A %= X */ + ctx->flags |= SEEN_X | SEEN_A; + /* Check if r_X is zero */ + b_off = b_imm(prog->len, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + emit_bcond(MIPS_COND_EQ, r_X, r_zero, b_off, ctx); + emit_load_imm(r_ret, 0, ctx); /* delay slot */ + emit_mod(r_A, r_X, ctx); + break; + case BPF_ALU | BPF_OR | BPF_K: + /* A |= K */ + ctx->flags |= SEEN_A; + emit_ori(r_A, r_A, k, ctx); + break; + case BPF_ALU | BPF_OR | BPF_X: + /* A |= X */ + ctx->flags |= SEEN_A; + emit_ori(r_A, r_A, r_X, ctx); + break; + case BPF_ALU | BPF_XOR | BPF_K: + /* A ^= k */ + ctx->flags |= SEEN_A; + emit_xori(r_A, r_A, k, ctx); + break; + case BPF_ANC | SKF_AD_ALU_XOR_X: + case BPF_ALU | BPF_XOR | BPF_X: + /* A ^= X */ + ctx->flags |= SEEN_A; + emit_xor(r_A, r_A, r_X, ctx); + break; + case BPF_ALU | BPF_AND | BPF_K: + /* A &= K */ + ctx->flags |= SEEN_A; + emit_andi(r_A, r_A, k, ctx); + break; + case BPF_ALU | BPF_AND | BPF_X: + /* A &= X */ + ctx->flags |= SEEN_A | SEEN_X; + emit_and(r_A, r_A, r_X, ctx); + break; + case BPF_ALU | BPF_LSH | BPF_K: + /* A <<= K */ + ctx->flags |= SEEN_A; + emit_sll(r_A, r_A, k, ctx); + break; + case BPF_ALU | BPF_LSH | BPF_X: + /* A <<= X */ + ctx->flags |= SEEN_A | SEEN_X; + emit_sllv(r_A, r_A, r_X, ctx); + break; + case BPF_ALU | BPF_RSH | BPF_K: + /* A >>= K */ + ctx->flags |= SEEN_A; + emit_srl(r_A, r_A, k, ctx); + break; + case BPF_ALU | BPF_RSH | BPF_X: + ctx->flags |= SEEN_A | SEEN_X; + emit_srlv(r_A, r_A, r_X, ctx); + break; + case BPF_ALU | BPF_NEG: + /* A = -A */ + ctx->flags |= SEEN_A; + emit_neg(r_A, ctx); + break; + case BPF_JMP | BPF_JA: + /* pc += K */ + b_off = b_imm(i + k + 1, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + emit_b(b_off, ctx); + emit_nop(ctx); + break; + case BPF_JMP | BPF_JEQ | BPF_K: + /* pc += ( A == K ) ? pc->jt : pc->jf */ + condt = MIPS_COND_EQ | MIPS_COND_K; + goto jmp_cmp; + case BPF_JMP | BPF_JEQ | BPF_X: + ctx->flags |= SEEN_X; + /* pc += ( A == X ) ? pc->jt : pc->jf */ + condt = MIPS_COND_EQ | MIPS_COND_X; + goto jmp_cmp; + case BPF_JMP | BPF_JGE | BPF_K: + /* pc += ( A >= K ) ? pc->jt : pc->jf */ + condt = MIPS_COND_GE | MIPS_COND_K; + goto jmp_cmp; + case BPF_JMP | BPF_JGE | BPF_X: + ctx->flags |= SEEN_X; + /* pc += ( A >= X ) ? pc->jt : pc->jf */ + condt = MIPS_COND_GE | MIPS_COND_X; + goto jmp_cmp; + case BPF_JMP | BPF_JGT | BPF_K: + /* pc += ( A > K ) ? pc->jt : pc->jf */ + condt = MIPS_COND_GT | MIPS_COND_K; + goto jmp_cmp; + case BPF_JMP | BPF_JGT | BPF_X: + ctx->flags |= SEEN_X; + /* pc += ( A > X ) ? pc->jt : pc->jf */ + condt = MIPS_COND_GT | MIPS_COND_X; +jmp_cmp: + /* Greater or Equal */ + if ((condt & MIPS_COND_GE) || + (condt & MIPS_COND_GT)) { + if (condt & MIPS_COND_K) { /* K */ + ctx->flags |= SEEN_A; + emit_sltiu(r_s0, r_A, k, ctx); + } else { /* X */ + ctx->flags |= SEEN_A | + SEEN_X; + emit_sltu(r_s0, r_A, r_X, ctx); + } + /* A < (K|X) ? r_scrach = 1 */ + b_off = b_imm(i + inst->jf + 1, ctx); + emit_bcond(MIPS_COND_NE, r_s0, r_zero, b_off, + ctx); + emit_nop(ctx); + /* A > (K|X) ? scratch = 0 */ + if (condt & MIPS_COND_GT) { + /* Checking for equality */ + ctx->flags |= SEEN_A | SEEN_X; + if (condt & MIPS_COND_K) + emit_load_imm(r_s0, k, ctx); + else + emit_jit_reg_move(r_s0, r_X, + ctx); + b_off = b_imm(i + inst->jf + 1, ctx); + emit_bcond(MIPS_COND_EQ, r_A, r_s0, + b_off, ctx); + emit_nop(ctx); + /* Finally, A > K|X */ + b_off = b_imm(i + inst->jt + 1, ctx); + emit_b(b_off, ctx); + emit_nop(ctx); + } else { + /* A >= (K|X) so jump */ + b_off = b_imm(i + inst->jt + 1, ctx); + emit_b(b_off, ctx); + emit_nop(ctx); + } + } else { + /* A == K|X */ + if (condt & MIPS_COND_K) { /* K */ + ctx->flags |= SEEN_A; + emit_load_imm(r_s0, k, ctx); + /* jump true */ + b_off = b_imm(i + inst->jt + 1, ctx); + emit_bcond(MIPS_COND_EQ, r_A, r_s0, + b_off, ctx); + emit_nop(ctx); + /* jump false */ + b_off = b_imm(i + inst->jf + 1, + ctx); + emit_bcond(MIPS_COND_NE, r_A, r_s0, + b_off, ctx); + emit_nop(ctx); + } else { /* X */ + /* jump true */ + ctx->flags |= SEEN_A | SEEN_X; + b_off = b_imm(i + inst->jt + 1, + ctx); + emit_bcond(MIPS_COND_EQ, r_A, r_X, + b_off, ctx); + emit_nop(ctx); + /* jump false */ + b_off = b_imm(i + inst->jf + 1, ctx); + emit_bcond(MIPS_COND_NE, r_A, r_X, + b_off, ctx); + emit_nop(ctx); + } + } + break; + case BPF_JMP | BPF_JSET | BPF_K: + ctx->flags |= SEEN_A; + /* pc += (A & K) ? pc -> jt : pc -> jf */ + emit_load_imm(r_s1, k, ctx); + emit_and(r_s0, r_A, r_s1, ctx); + /* jump true */ + b_off = b_imm(i + inst->jt + 1, ctx); + emit_bcond(MIPS_COND_NE, r_s0, r_zero, b_off, ctx); + emit_nop(ctx); + /* jump false */ + b_off = b_imm(i + inst->jf + 1, ctx); + emit_b(b_off, ctx); + emit_nop(ctx); + break; + case BPF_JMP | BPF_JSET | BPF_X: + ctx->flags |= SEEN_X | SEEN_A; + /* pc += (A & X) ? pc -> jt : pc -> jf */ + emit_and(r_s0, r_A, r_X, ctx); + /* jump true */ + b_off = b_imm(i + inst->jt + 1, ctx); + emit_bcond(MIPS_COND_NE, r_s0, r_zero, b_off, ctx); + emit_nop(ctx); + /* jump false */ + b_off = b_imm(i + inst->jf + 1, ctx); + emit_b(b_off, ctx); + emit_nop(ctx); + break; + case BPF_RET | BPF_A: + ctx->flags |= SEEN_A; + if (i != prog->len - 1) { + /* + * If this is not the last instruction + * then jump to the epilogue + */ + b_off = b_imm(prog->len, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + emit_b(b_off, ctx); + } + emit_reg_move(r_ret, r_A, ctx); /* delay slot */ + break; + case BPF_RET | BPF_K: + /* + * It can emit two instructions so it does not fit on + * the delay slot. + */ + emit_load_imm(r_ret, k, ctx); + if (i != prog->len - 1) { + /* + * If this is not the last instruction + * then jump to the epilogue + */ + b_off = b_imm(prog->len, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + emit_b(b_off, ctx); + emit_nop(ctx); + } + break; + case BPF_MISC | BPF_TAX: + /* X = A */ + ctx->flags |= SEEN_X | SEEN_A; + emit_jit_reg_move(r_X, r_A, ctx); + break; + case BPF_MISC | BPF_TXA: + /* A = X */ + ctx->flags |= SEEN_A | SEEN_X; + emit_jit_reg_move(r_A, r_X, ctx); + break; + /* AUX */ + case BPF_ANC | SKF_AD_PROTOCOL: + /* A = ntohs(skb->protocol */ + ctx->flags |= SEEN_SKB | SEEN_OFF | SEEN_A; + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, + protocol) != 2); + off = offsetof(struct sk_buff, protocol); + emit_half_load(r_A, r_skb, off, ctx); +#ifdef CONFIG_CPU_LITTLE_ENDIAN + /* This needs little endian fixup */ + if (cpu_has_wsbh) { + /* R2 and later have the wsbh instruction */ + emit_wsbh(r_A, r_A, ctx); + } else { + /* Get first byte */ + emit_andi(r_tmp_imm, r_A, 0xff, ctx); + /* Shift it */ + emit_sll(r_tmp, r_tmp_imm, 8, ctx); + /* Get second byte */ + emit_srl(r_tmp_imm, r_A, 8, ctx); + emit_andi(r_tmp_imm, r_tmp_imm, 0xff, ctx); + /* Put everyting together in r_A */ + emit_or(r_A, r_tmp, r_tmp_imm, ctx); + } +#endif + break; + case BPF_ANC | SKF_AD_CPU: + ctx->flags |= SEEN_A | SEEN_OFF; + /* A = current_thread_info()->cpu */ + BUILD_BUG_ON(FIELD_SIZEOF(struct thread_info, + cpu) != 4); + off = offsetof(struct thread_info, cpu); + /* $28/gp points to the thread_info struct */ + emit_load(r_A, 28, off, ctx); + break; + case BPF_ANC | SKF_AD_IFINDEX: + /* A = skb->dev->ifindex */ + case BPF_ANC | SKF_AD_HATYPE: + /* A = skb->dev->type */ + ctx->flags |= SEEN_SKB | SEEN_A; + off = offsetof(struct sk_buff, dev); + /* Load *dev pointer */ + emit_load_ptr(r_s0, r_skb, off, ctx); + /* error (0) in the delay slot */ + b_off = b_imm(prog->len, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + emit_bcond(MIPS_COND_EQ, r_s0, r_zero, b_off, ctx); + emit_reg_move(r_ret, r_zero, ctx); + if (code == (BPF_ANC | SKF_AD_IFINDEX)) { + BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4); + off = offsetof(struct net_device, ifindex); + emit_load(r_A, r_s0, off, ctx); + } else { /* (code == (BPF_ANC | SKF_AD_HATYPE) */ + BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2); + off = offsetof(struct net_device, type); + emit_half_load_unsigned(r_A, r_s0, off, ctx); + } + break; + case BPF_ANC | SKF_AD_MARK: + ctx->flags |= SEEN_SKB | SEEN_A; + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4); + off = offsetof(struct sk_buff, mark); + emit_load(r_A, r_skb, off, ctx); + break; + case BPF_ANC | SKF_AD_RXHASH: + ctx->flags |= SEEN_SKB | SEEN_A; + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4); + off = offsetof(struct sk_buff, hash); + emit_load(r_A, r_skb, off, ctx); + break; + case BPF_ANC | SKF_AD_VLAN_TAG: + case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT: + ctx->flags |= SEEN_SKB | SEEN_A; + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, + vlan_tci) != 2); + off = offsetof(struct sk_buff, vlan_tci); + emit_half_load_unsigned(r_s0, r_skb, off, ctx); + if (code == (BPF_ANC | SKF_AD_VLAN_TAG)) { + emit_andi(r_A, r_s0, (u16)~VLAN_TAG_PRESENT, ctx); + } else { + emit_andi(r_A, r_s0, VLAN_TAG_PRESENT, ctx); + /* return 1 if present */ + emit_sltu(r_A, r_zero, r_A, ctx); + } + break; + case BPF_ANC | SKF_AD_PKTTYPE: + ctx->flags |= SEEN_SKB; + + emit_load_byte(r_tmp, r_skb, PKT_TYPE_OFFSET(), ctx); + /* Keep only the last 3 bits */ + emit_andi(r_A, r_tmp, PKT_TYPE_MAX, ctx); +#ifdef __BIG_ENDIAN_BITFIELD + /* Get the actual packet type to the lower 3 bits */ + emit_srl(r_A, r_A, 5, ctx); +#endif + break; + case BPF_ANC | SKF_AD_QUEUE: + ctx->flags |= SEEN_SKB | SEEN_A; + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, + queue_mapping) != 2); + BUILD_BUG_ON(offsetof(struct sk_buff, + queue_mapping) > 0xff); + off = offsetof(struct sk_buff, queue_mapping); + emit_half_load_unsigned(r_A, r_skb, off, ctx); + break; + default: + pr_debug("%s: Unhandled opcode: 0x%02x\n", __FILE__, + inst->code); + return -1; + } + } + + /* compute offsets only during the first pass */ + if (ctx->target == NULL) + ctx->offsets[i] = ctx->idx * 4; + + return 0; +} + +void bpf_jit_compile(struct bpf_prog *fp) +{ + struct jit_ctx ctx; + unsigned int alloc_size, tmp_idx; + + if (!bpf_jit_enable) + return; + + memset(&ctx, 0, sizeof(ctx)); + + ctx.offsets = kcalloc(fp->len + 1, sizeof(*ctx.offsets), GFP_KERNEL); + if (ctx.offsets == NULL) + return; + + ctx.skf = fp; + + if (build_body(&ctx)) + goto out; + + tmp_idx = ctx.idx; + build_prologue(&ctx); + ctx.prologue_bytes = (ctx.idx - tmp_idx) * 4; + /* just to complete the ctx.idx count */ + build_epilogue(&ctx); + + alloc_size = 4 * ctx.idx; + ctx.target = module_alloc(alloc_size); + if (ctx.target == NULL) + goto out; + + /* Clean it */ + memset(ctx.target, 0, alloc_size); + + ctx.idx = 0; + + /* Generate the actual JIT code */ + build_prologue(&ctx); + if (build_body(&ctx)) { + module_memfree(ctx.target); + goto out; + } + build_epilogue(&ctx); + + /* Update the icache */ + flush_icache_range((ptr)ctx.target, (ptr)(ctx.target + ctx.idx)); + + if (bpf_jit_enable > 1) + /* Dump JIT code */ + bpf_jit_dump(fp->len, alloc_size, 2, ctx.target); + + fp->bpf_func = (void *)ctx.target; + fp->jited = 1; + +out: + kfree(ctx.offsets); +} + +void bpf_jit_free(struct bpf_prog *fp) +{ + if (fp->jited) + module_memfree(fp->bpf_func); + + bpf_prog_unlock_free(fp); +} diff --git a/arch/mips/net/bpf_jit.h b/arch/mips/net/bpf_jit.h new file mode 100644 index 000000000..8f9f54841 --- /dev/null +++ b/arch/mips/net/bpf_jit.h @@ -0,0 +1,84 @@ +/* + * Just-In-Time compiler for BPF filters on MIPS + * + * Copyright (c) 2014 Imagination Technologies Ltd. + * Author: Markos Chandras <markos.chandras@imgtec.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. + */ + +#ifndef BPF_JIT_MIPS_OP_H +#define BPF_JIT_MIPS_OP_H + +/* Registers used by JIT */ +#define MIPS_R_ZERO 0 +#define MIPS_R_V0 2 +#define MIPS_R_A0 4 +#define MIPS_R_A1 5 +#define MIPS_R_T4 12 +#define MIPS_R_T5 13 +#define MIPS_R_T6 14 +#define MIPS_R_T7 15 +#define MIPS_R_S0 16 +#define MIPS_R_S1 17 +#define MIPS_R_S2 18 +#define MIPS_R_S3 19 +#define MIPS_R_S4 20 +#define MIPS_R_S5 21 +#define MIPS_R_S6 22 +#define MIPS_R_S7 23 +#define MIPS_R_SP 29 +#define MIPS_R_RA 31 + +/* Conditional codes */ +#define MIPS_COND_EQ 0x1 +#define MIPS_COND_GE (0x1 << 1) +#define MIPS_COND_GT (0x1 << 2) +#define MIPS_COND_NE (0x1 << 3) +#define MIPS_COND_ALL (0x1 << 4) +/* Conditionals on X register or K immediate */ +#define MIPS_COND_X (0x1 << 5) +#define MIPS_COND_K (0x1 << 6) + +#define r_ret MIPS_R_V0 + +/* + * Use 2 scratch registers to avoid pipeline interlocks. + * There is no overhead during epilogue and prologue since + * any of the $s0-$s6 registers will only be preserved if + * they are going to actually be used. + */ +#define r_skb_hl MIPS_R_S0 /* skb header length */ +#define r_skb_data MIPS_R_S1 /* skb actual data */ +#define r_off MIPS_R_S2 +#define r_A MIPS_R_S3 +#define r_X MIPS_R_S4 +#define r_skb MIPS_R_S5 +#define r_M MIPS_R_S6 +#define r_skb_len MIPS_R_S7 +#define r_s0 MIPS_R_T4 /* scratch reg 1 */ +#define r_s1 MIPS_R_T5 /* scratch reg 2 */ +#define r_tmp_imm MIPS_R_T6 /* No need to preserve this */ +#define r_tmp MIPS_R_T7 /* No need to preserve this */ +#define r_zero MIPS_R_ZERO +#define r_sp MIPS_R_SP +#define r_ra MIPS_R_RA + +#ifndef __ASSEMBLY__ + +/* Declare ASM helpers */ + +#define DECLARE_LOAD_FUNC(func) \ + extern u8 func(unsigned long *skb, int offset); \ + extern u8 func##_negative(unsigned long *skb, int offset); \ + extern u8 func##_positive(unsigned long *skb, int offset) + +DECLARE_LOAD_FUNC(sk_load_word); +DECLARE_LOAD_FUNC(sk_load_half); +DECLARE_LOAD_FUNC(sk_load_byte); + +#endif + +#endif /* BPF_JIT_MIPS_OP_H */ diff --git a/arch/mips/net/bpf_jit_asm.S b/arch/mips/net/bpf_jit_asm.S new file mode 100644 index 000000000..57154c588 --- /dev/null +++ b/arch/mips/net/bpf_jit_asm.S @@ -0,0 +1,285 @@ +/* + * bpf_jib_asm.S: Packet/header access helper functions for MIPS/MIPS64 BPF + * compiler. + * + * Copyright (C) 2015 Imagination Technologies Ltd. + * Author: Markos Chandras <markos.chandras@imgtec.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 <asm/asm.h> +#include <asm/isa-rev.h> +#include <asm/regdef.h> +#include "bpf_jit.h" + +/* ABI + * + * r_skb_hl skb header length + * r_skb_data skb data + * r_off(a1) offset register + * r_A BPF register A + * r_X PF register X + * r_skb(a0) *skb + * r_M *scratch memory + * r_skb_le skb length + * r_s0 Scratch register 0 + * r_s1 Scratch register 1 + * + * On entry: + * a0: *skb + * a1: offset (imm or imm + X) + * + * All non-BPF-ABI registers are free for use. On return, we only + * care about r_ret. The BPF-ABI registers are assumed to remain + * unmodified during the entire filter operation. + */ + +#define skb a0 +#define offset a1 +#define SKF_LL_OFF (-0x200000) /* Can't include linux/filter.h in assembly */ + + /* We know better :) so prevent assembler reordering etc */ + .set noreorder + +#define is_offset_negative(TYPE) \ + /* If offset is negative we have more work to do */ \ + slti t0, offset, 0; \ + bgtz t0, bpf_slow_path_##TYPE##_neg; \ + /* Be careful what follows in DS. */ + +#define is_offset_in_header(SIZE, TYPE) \ + /* Reading from header? */ \ + addiu $r_s0, $r_skb_hl, -SIZE; \ + slt t0, $r_s0, offset; \ + bgtz t0, bpf_slow_path_##TYPE; \ + +LEAF(sk_load_word) + is_offset_negative(word) +FEXPORT(sk_load_word_positive) + is_offset_in_header(4, word) + /* Offset within header boundaries */ + PTR_ADDU t1, $r_skb_data, offset + .set reorder + lw $r_A, 0(t1) + .set noreorder +#ifdef CONFIG_CPU_LITTLE_ENDIAN +# if MIPS_ISA_REV >= 2 + wsbh t0, $r_A + rotr $r_A, t0, 16 +# else + sll t0, $r_A, 24 + srl t1, $r_A, 24 + srl t2, $r_A, 8 + or t0, t0, t1 + andi t2, t2, 0xff00 + andi t1, $r_A, 0xff00 + or t0, t0, t2 + sll t1, t1, 8 + or $r_A, t0, t1 +# endif +#endif + jr $r_ra + move $r_ret, zero + END(sk_load_word) + +LEAF(sk_load_half) + is_offset_negative(half) +FEXPORT(sk_load_half_positive) + is_offset_in_header(2, half) + /* Offset within header boundaries */ + PTR_ADDU t1, $r_skb_data, offset + lhu $r_A, 0(t1) +#ifdef CONFIG_CPU_LITTLE_ENDIAN +# if MIPS_ISA_REV >= 2 + wsbh $r_A, $r_A +# else + sll t0, $r_A, 8 + srl t1, $r_A, 8 + andi t0, t0, 0xff00 + or $r_A, t0, t1 +# endif +#endif + jr $r_ra + move $r_ret, zero + END(sk_load_half) + +LEAF(sk_load_byte) + is_offset_negative(byte) +FEXPORT(sk_load_byte_positive) + is_offset_in_header(1, byte) + /* Offset within header boundaries */ + PTR_ADDU t1, $r_skb_data, offset + lbu $r_A, 0(t1) + jr $r_ra + move $r_ret, zero + END(sk_load_byte) + +/* + * call skb_copy_bits: + * (prototype in linux/skbuff.h) + * + * int skb_copy_bits(sk_buff *skb, int offset, void *to, int len) + * + * o32 mandates we leave 4 spaces for argument registers in case + * the callee needs to use them. Even though we don't care about + * the argument registers ourselves, we need to allocate that space + * to remain ABI compliant since the callee may want to use that space. + * We also allocate 2 more spaces for $r_ra and our return register (*to). + * + * n64 is a bit different. The *caller* will allocate the space to preserve + * the arguments. So in 64-bit kernels, we allocate the 4-arg space for no + * good reason but it does not matter that much really. + * + * (void *to) is returned in r_s0 + * + */ +#ifdef CONFIG_CPU_LITTLE_ENDIAN +#define DS_OFFSET(SIZE) (4 * SZREG) +#else +#define DS_OFFSET(SIZE) ((4 * SZREG) + (4 - SIZE)) +#endif +#define bpf_slow_path_common(SIZE) \ + /* Quick check. Are we within reasonable boundaries? */ \ + LONG_ADDIU $r_s1, $r_skb_len, -SIZE; \ + sltu $r_s0, offset, $r_s1; \ + beqz $r_s0, fault; \ + /* Load 4th argument in DS */ \ + LONG_ADDIU a3, zero, SIZE; \ + PTR_ADDIU $r_sp, $r_sp, -(6 * SZREG); \ + PTR_LA t0, skb_copy_bits; \ + PTR_S $r_ra, (5 * SZREG)($r_sp); \ + /* Assign low slot to a2 */ \ + PTR_ADDIU a2, $r_sp, DS_OFFSET(SIZE); \ + jalr t0; \ + /* Reset our destination slot (DS but it's ok) */ \ + INT_S zero, (4 * SZREG)($r_sp); \ + /* \ + * skb_copy_bits returns 0 on success and -EFAULT \ + * on error. Our data live in a2. Do not bother with \ + * our data if an error has been returned. \ + */ \ + /* Restore our frame */ \ + PTR_L $r_ra, (5 * SZREG)($r_sp); \ + INT_L $r_s0, (4 * SZREG)($r_sp); \ + bltz v0, fault; \ + PTR_ADDIU $r_sp, $r_sp, 6 * SZREG; \ + move $r_ret, zero; \ + +NESTED(bpf_slow_path_word, (6 * SZREG), $r_sp) + bpf_slow_path_common(4) +#ifdef CONFIG_CPU_LITTLE_ENDIAN +# if MIPS_ISA_REV >= 2 + wsbh t0, $r_s0 + jr $r_ra + rotr $r_A, t0, 16 +# else + sll t0, $r_s0, 24 + srl t1, $r_s0, 24 + srl t2, $r_s0, 8 + or t0, t0, t1 + andi t2, t2, 0xff00 + andi t1, $r_s0, 0xff00 + or t0, t0, t2 + sll t1, t1, 8 + jr $r_ra + or $r_A, t0, t1 +# endif +#else + jr $r_ra + move $r_A, $r_s0 +#endif + + END(bpf_slow_path_word) + +NESTED(bpf_slow_path_half, (6 * SZREG), $r_sp) + bpf_slow_path_common(2) +#ifdef CONFIG_CPU_LITTLE_ENDIAN +# if MIPS_ISA_REV >= 2 + jr $r_ra + wsbh $r_A, $r_s0 +# else + sll t0, $r_s0, 8 + andi t1, $r_s0, 0xff00 + andi t0, t0, 0xff00 + srl t1, t1, 8 + jr $r_ra + or $r_A, t0, t1 +# endif +#else + jr $r_ra + move $r_A, $r_s0 +#endif + + END(bpf_slow_path_half) + +NESTED(bpf_slow_path_byte, (6 * SZREG), $r_sp) + bpf_slow_path_common(1) + jr $r_ra + move $r_A, $r_s0 + + END(bpf_slow_path_byte) + +/* + * Negative entry points + */ + .macro bpf_is_end_of_data + li t0, SKF_LL_OFF + /* Reading link layer data? */ + slt t1, offset, t0 + bgtz t1, fault + /* Be careful what follows in DS. */ + .endm +/* + * call skb_copy_bits: + * (prototype in linux/filter.h) + * + * void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, + * int k, unsigned int size) + * + * see above (bpf_slow_path_common) for ABI restrictions + */ +#define bpf_negative_common(SIZE) \ + PTR_ADDIU $r_sp, $r_sp, -(6 * SZREG); \ + PTR_LA t0, bpf_internal_load_pointer_neg_helper; \ + PTR_S $r_ra, (5 * SZREG)($r_sp); \ + jalr t0; \ + li a2, SIZE; \ + PTR_L $r_ra, (5 * SZREG)($r_sp); \ + /* Check return pointer */ \ + beqz v0, fault; \ + PTR_ADDIU $r_sp, $r_sp, 6 * SZREG; \ + /* Preserve our pointer */ \ + move $r_s0, v0; \ + /* Set return value */ \ + move $r_ret, zero; \ + +bpf_slow_path_word_neg: + bpf_is_end_of_data +NESTED(sk_load_word_negative, (6 * SZREG), $r_sp) + bpf_negative_common(4) + jr $r_ra + lw $r_A, 0($r_s0) + END(sk_load_word_negative) + +bpf_slow_path_half_neg: + bpf_is_end_of_data +NESTED(sk_load_half_negative, (6 * SZREG), $r_sp) + bpf_negative_common(2) + jr $r_ra + lhu $r_A, 0($r_s0) + END(sk_load_half_negative) + +bpf_slow_path_byte_neg: + bpf_is_end_of_data +NESTED(sk_load_byte_negative, (6 * SZREG), $r_sp) + bpf_negative_common(1) + jr $r_ra + lbu $r_A, 0($r_s0) + END(sk_load_byte_negative) + +fault: + jr $r_ra + addiu $r_ret, zero, 1 diff --git a/arch/mips/net/ebpf_jit.c b/arch/mips/net/ebpf_jit.c new file mode 100644 index 000000000..947a7172c --- /dev/null +++ b/arch/mips/net/ebpf_jit.c @@ -0,0 +1,1849 @@ +/* + * Just-In-Time compiler for eBPF filters on MIPS + * + * Copyright (c) 2017 Cavium, Inc. + * + * Based on code from: + * + * Copyright (c) 2014 Imagination Technologies Ltd. + * Author: Markos Chandras <markos.chandras@imgtec.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/bitops.h> +#include <linux/errno.h> +#include <linux/filter.h> +#include <linux/bpf.h> +#include <linux/slab.h> +#include <asm/bitops.h> +#include <asm/byteorder.h> +#include <asm/cacheflush.h> +#include <asm/cpu-features.h> +#include <asm/uasm.h> + +/* Registers used by JIT */ +#define MIPS_R_ZERO 0 +#define MIPS_R_AT 1 +#define MIPS_R_V0 2 /* BPF_R0 */ +#define MIPS_R_V1 3 +#define MIPS_R_A0 4 /* BPF_R1 */ +#define MIPS_R_A1 5 /* BPF_R2 */ +#define MIPS_R_A2 6 /* BPF_R3 */ +#define MIPS_R_A3 7 /* BPF_R4 */ +#define MIPS_R_A4 8 /* BPF_R5 */ +#define MIPS_R_T4 12 /* BPF_AX */ +#define MIPS_R_T5 13 +#define MIPS_R_T6 14 +#define MIPS_R_T7 15 +#define MIPS_R_S0 16 /* BPF_R6 */ +#define MIPS_R_S1 17 /* BPF_R7 */ +#define MIPS_R_S2 18 /* BPF_R8 */ +#define MIPS_R_S3 19 /* BPF_R9 */ +#define MIPS_R_S4 20 /* BPF_TCC */ +#define MIPS_R_S5 21 +#define MIPS_R_S6 22 +#define MIPS_R_S7 23 +#define MIPS_R_T8 24 +#define MIPS_R_T9 25 +#define MIPS_R_SP 29 +#define MIPS_R_RA 31 + +/* eBPF flags */ +#define EBPF_SAVE_S0 BIT(0) +#define EBPF_SAVE_S1 BIT(1) +#define EBPF_SAVE_S2 BIT(2) +#define EBPF_SAVE_S3 BIT(3) +#define EBPF_SAVE_S4 BIT(4) +#define EBPF_SAVE_RA BIT(5) +#define EBPF_SEEN_FP BIT(6) +#define EBPF_SEEN_TC BIT(7) +#define EBPF_TCC_IN_V1 BIT(8) + +/* + * For the mips64 ISA, we need to track the value range or type for + * each JIT register. The BPF machine requires zero extended 32-bit + * values, but the mips64 ISA requires sign extended 32-bit values. + * At each point in the BPF program we track the state of every + * register so that we can zero extend or sign extend as the BPF + * semantics require. + */ +enum reg_val_type { + /* uninitialized */ + REG_UNKNOWN, + /* not known to be 32-bit compatible. */ + REG_64BIT, + /* 32-bit compatible, no truncation needed for 64-bit ops. */ + REG_64BIT_32BIT, + /* 32-bit compatible, need truncation for 64-bit ops. */ + REG_32BIT, + /* 32-bit zero extended. */ + REG_32BIT_ZERO_EX, + /* 32-bit no sign/zero extension needed. */ + REG_32BIT_POS +}; + +/* + * high bit of offsets indicates if long branch conversion done at + * this insn. + */ +#define OFFSETS_B_CONV BIT(31) + +/** + * struct jit_ctx - JIT context + * @skf: The sk_filter + * @stack_size: eBPF stack size + * @idx: Instruction index + * @flags: JIT flags + * @offsets: Instruction offsets + * @target: Memory location for the compiled filter + * @reg_val_types Packed enum reg_val_type for each register. + */ +struct jit_ctx { + const struct bpf_prog *skf; + int stack_size; + u32 idx; + u32 flags; + u32 *offsets; + u32 *target; + u64 *reg_val_types; + unsigned int long_b_conversion:1; + unsigned int gen_b_offsets:1; + unsigned int use_bbit_insns:1; +}; + +static void set_reg_val_type(u64 *rvt, int reg, enum reg_val_type type) +{ + *rvt &= ~(7ull << (reg * 3)); + *rvt |= ((u64)type << (reg * 3)); +} + +static enum reg_val_type get_reg_val_type(const struct jit_ctx *ctx, + int index, int reg) +{ + return (ctx->reg_val_types[index] >> (reg * 3)) & 7; +} + +/* Simply emit the instruction if the JIT memory space has been allocated */ +#define emit_instr(ctx, func, ...) \ +do { \ + if ((ctx)->target != NULL) { \ + u32 *p = &(ctx)->target[ctx->idx]; \ + uasm_i_##func(&p, ##__VA_ARGS__); \ + } \ + (ctx)->idx++; \ +} while (0) + +static unsigned int j_target(struct jit_ctx *ctx, int target_idx) +{ + unsigned long target_va, base_va; + unsigned int r; + + if (!ctx->target) + return 0; + + base_va = (unsigned long)ctx->target; + target_va = base_va + (ctx->offsets[target_idx] & ~OFFSETS_B_CONV); + + if ((base_va & ~0x0ffffffful) != (target_va & ~0x0ffffffful)) + return (unsigned int)-1; + r = target_va & 0x0ffffffful; + return r; +} + +/* Compute the immediate value for PC-relative branches. */ +static u32 b_imm(unsigned int tgt, struct jit_ctx *ctx) +{ + if (!ctx->gen_b_offsets) + return 0; + + /* + * We want a pc-relative branch. tgt is the instruction offset + * we want to jump to. + + * Branch on MIPS: + * I: target_offset <- sign_extend(offset) + * I+1: PC += target_offset (delay slot) + * + * ctx->idx currently points to the branch instruction + * but the offset is added to the delay slot so we need + * to subtract 4. + */ + return (ctx->offsets[tgt] & ~OFFSETS_B_CONV) - + (ctx->idx * 4) - 4; +} + +enum which_ebpf_reg { + src_reg, + src_reg_no_fp, + dst_reg, + dst_reg_fp_ok +}; + +/* + * For eBPF, the register mapping naturally falls out of the + * requirements of eBPF and the MIPS n64 ABI. We don't maintain a + * separate frame pointer, so BPF_REG_10 relative accesses are + * adjusted to be $sp relative. + */ +int ebpf_to_mips_reg(struct jit_ctx *ctx, const struct bpf_insn *insn, + enum which_ebpf_reg w) +{ + int ebpf_reg = (w == src_reg || w == src_reg_no_fp) ? + insn->src_reg : insn->dst_reg; + + switch (ebpf_reg) { + case BPF_REG_0: + return MIPS_R_V0; + case BPF_REG_1: + return MIPS_R_A0; + case BPF_REG_2: + return MIPS_R_A1; + case BPF_REG_3: + return MIPS_R_A2; + case BPF_REG_4: + return MIPS_R_A3; + case BPF_REG_5: + return MIPS_R_A4; + case BPF_REG_6: + ctx->flags |= EBPF_SAVE_S0; + return MIPS_R_S0; + case BPF_REG_7: + ctx->flags |= EBPF_SAVE_S1; + return MIPS_R_S1; + case BPF_REG_8: + ctx->flags |= EBPF_SAVE_S2; + return MIPS_R_S2; + case BPF_REG_9: + ctx->flags |= EBPF_SAVE_S3; + return MIPS_R_S3; + case BPF_REG_10: + if (w == dst_reg || w == src_reg_no_fp) + goto bad_reg; + ctx->flags |= EBPF_SEEN_FP; + /* + * Needs special handling, return something that + * cannot be clobbered just in case. + */ + return MIPS_R_ZERO; + case BPF_REG_AX: + return MIPS_R_T4; + default: +bad_reg: + WARN(1, "Illegal bpf reg: %d\n", ebpf_reg); + return -EINVAL; + } +} +/* + * eBPF stack frame will be something like: + * + * Entry $sp ------> +--------------------------------+ + * | $ra (optional) | + * +--------------------------------+ + * | $s0 (optional) | + * +--------------------------------+ + * | $s1 (optional) | + * +--------------------------------+ + * | $s2 (optional) | + * +--------------------------------+ + * | $s3 (optional) | + * +--------------------------------+ + * | $s4 (optional) | + * +--------------------------------+ + * | tmp-storage (if $ra saved) | + * $sp + tmp_offset --> +--------------------------------+ <--BPF_REG_10 + * | BPF_REG_10 relative storage | + * | MAX_BPF_STACK (optional) | + * | . | + * | . | + * | . | + * $sp --------> +--------------------------------+ + * + * If BPF_REG_10 is never referenced, then the MAX_BPF_STACK sized + * area is not allocated. + */ +static int gen_int_prologue(struct jit_ctx *ctx) +{ + int stack_adjust = 0; + int store_offset; + int locals_size; + + if (ctx->flags & EBPF_SAVE_RA) + /* + * If RA we are doing a function call and may need + * extra 8-byte tmp area. + */ + stack_adjust += 16; + if (ctx->flags & EBPF_SAVE_S0) + stack_adjust += 8; + if (ctx->flags & EBPF_SAVE_S1) + stack_adjust += 8; + if (ctx->flags & EBPF_SAVE_S2) + stack_adjust += 8; + if (ctx->flags & EBPF_SAVE_S3) + stack_adjust += 8; + if (ctx->flags & EBPF_SAVE_S4) + stack_adjust += 8; + + BUILD_BUG_ON(MAX_BPF_STACK & 7); + locals_size = (ctx->flags & EBPF_SEEN_FP) ? MAX_BPF_STACK : 0; + + stack_adjust += locals_size; + + ctx->stack_size = stack_adjust; + + /* + * First instruction initializes the tail call count (TCC). + * On tail call we skip this instruction, and the TCC is + * passed in $v1 from the caller. + */ + emit_instr(ctx, daddiu, MIPS_R_V1, MIPS_R_ZERO, MAX_TAIL_CALL_CNT); + if (stack_adjust) + emit_instr(ctx, daddiu, MIPS_R_SP, MIPS_R_SP, -stack_adjust); + else + return 0; + + store_offset = stack_adjust - 8; + + if (ctx->flags & EBPF_SAVE_RA) { + emit_instr(ctx, sd, MIPS_R_RA, store_offset, MIPS_R_SP); + store_offset -= 8; + } + if (ctx->flags & EBPF_SAVE_S0) { + emit_instr(ctx, sd, MIPS_R_S0, store_offset, MIPS_R_SP); + store_offset -= 8; + } + if (ctx->flags & EBPF_SAVE_S1) { + emit_instr(ctx, sd, MIPS_R_S1, store_offset, MIPS_R_SP); + store_offset -= 8; + } + if (ctx->flags & EBPF_SAVE_S2) { + emit_instr(ctx, sd, MIPS_R_S2, store_offset, MIPS_R_SP); + store_offset -= 8; + } + if (ctx->flags & EBPF_SAVE_S3) { + emit_instr(ctx, sd, MIPS_R_S3, store_offset, MIPS_R_SP); + store_offset -= 8; + } + if (ctx->flags & EBPF_SAVE_S4) { + emit_instr(ctx, sd, MIPS_R_S4, store_offset, MIPS_R_SP); + store_offset -= 8; + } + + if ((ctx->flags & EBPF_SEEN_TC) && !(ctx->flags & EBPF_TCC_IN_V1)) + emit_instr(ctx, daddu, MIPS_R_S4, MIPS_R_V1, MIPS_R_ZERO); + + return 0; +} + +static int build_int_epilogue(struct jit_ctx *ctx, int dest_reg) +{ + const struct bpf_prog *prog = ctx->skf; + int stack_adjust = ctx->stack_size; + int store_offset = stack_adjust - 8; + enum reg_val_type td; + int r0 = MIPS_R_V0; + + if (dest_reg == MIPS_R_RA) { + /* Don't let zero extended value escape. */ + td = get_reg_val_type(ctx, prog->len, BPF_REG_0); + if (td == REG_64BIT || td == REG_32BIT_ZERO_EX) + emit_instr(ctx, sll, r0, r0, 0); + } + + if (ctx->flags & EBPF_SAVE_RA) { + emit_instr(ctx, ld, MIPS_R_RA, store_offset, MIPS_R_SP); + store_offset -= 8; + } + if (ctx->flags & EBPF_SAVE_S0) { + emit_instr(ctx, ld, MIPS_R_S0, store_offset, MIPS_R_SP); + store_offset -= 8; + } + if (ctx->flags & EBPF_SAVE_S1) { + emit_instr(ctx, ld, MIPS_R_S1, store_offset, MIPS_R_SP); + store_offset -= 8; + } + if (ctx->flags & EBPF_SAVE_S2) { + emit_instr(ctx, ld, MIPS_R_S2, store_offset, MIPS_R_SP); + store_offset -= 8; + } + if (ctx->flags & EBPF_SAVE_S3) { + emit_instr(ctx, ld, MIPS_R_S3, store_offset, MIPS_R_SP); + store_offset -= 8; + } + if (ctx->flags & EBPF_SAVE_S4) { + emit_instr(ctx, ld, MIPS_R_S4, store_offset, MIPS_R_SP); + store_offset -= 8; + } + emit_instr(ctx, jr, dest_reg); + + if (stack_adjust) + emit_instr(ctx, daddiu, MIPS_R_SP, MIPS_R_SP, stack_adjust); + else + emit_instr(ctx, nop); + + return 0; +} + +static void gen_imm_to_reg(const struct bpf_insn *insn, int reg, + struct jit_ctx *ctx) +{ + if (insn->imm >= S16_MIN && insn->imm <= S16_MAX) { + emit_instr(ctx, addiu, reg, MIPS_R_ZERO, insn->imm); + } else { + int lower = (s16)(insn->imm & 0xffff); + int upper = insn->imm - lower; + + emit_instr(ctx, lui, reg, upper >> 16); + emit_instr(ctx, addiu, reg, reg, lower); + } +} + +static int gen_imm_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, + int idx) +{ + int upper_bound, lower_bound; + int dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + + if (dst < 0) + return dst; + + switch (BPF_OP(insn->code)) { + case BPF_MOV: + case BPF_ADD: + upper_bound = S16_MAX; + lower_bound = S16_MIN; + break; + case BPF_SUB: + upper_bound = -(int)S16_MIN; + lower_bound = -(int)S16_MAX; + break; + case BPF_AND: + case BPF_OR: + case BPF_XOR: + upper_bound = 0xffff; + lower_bound = 0; + break; + case BPF_RSH: + case BPF_LSH: + case BPF_ARSH: + /* Shift amounts are truncated, no need for bounds */ + upper_bound = S32_MAX; + lower_bound = S32_MIN; + break; + default: + return -EINVAL; + } + + /* + * Immediate move clobbers the register, so no sign/zero + * extension needed. + */ + if (BPF_CLASS(insn->code) == BPF_ALU64 && + BPF_OP(insn->code) != BPF_MOV && + get_reg_val_type(ctx, idx, insn->dst_reg) == REG_32BIT) + emit_instr(ctx, dinsu, dst, MIPS_R_ZERO, 32, 32); + /* BPF_ALU | BPF_LSH doesn't need separate sign extension */ + if (BPF_CLASS(insn->code) == BPF_ALU && + BPF_OP(insn->code) != BPF_LSH && + BPF_OP(insn->code) != BPF_MOV && + get_reg_val_type(ctx, idx, insn->dst_reg) != REG_32BIT) + emit_instr(ctx, sll, dst, dst, 0); + + if (insn->imm >= lower_bound && insn->imm <= upper_bound) { + /* single insn immediate case */ + switch (BPF_OP(insn->code) | BPF_CLASS(insn->code)) { + case BPF_ALU64 | BPF_MOV: + emit_instr(ctx, daddiu, dst, MIPS_R_ZERO, insn->imm); + break; + case BPF_ALU64 | BPF_AND: + case BPF_ALU | BPF_AND: + emit_instr(ctx, andi, dst, dst, insn->imm); + break; + case BPF_ALU64 | BPF_OR: + case BPF_ALU | BPF_OR: + emit_instr(ctx, ori, dst, dst, insn->imm); + break; + case BPF_ALU64 | BPF_XOR: + case BPF_ALU | BPF_XOR: + emit_instr(ctx, xori, dst, dst, insn->imm); + break; + case BPF_ALU64 | BPF_ADD: + emit_instr(ctx, daddiu, dst, dst, insn->imm); + break; + case BPF_ALU64 | BPF_SUB: + emit_instr(ctx, daddiu, dst, dst, -insn->imm); + break; + case BPF_ALU64 | BPF_RSH: + emit_instr(ctx, dsrl_safe, dst, dst, insn->imm & 0x3f); + break; + case BPF_ALU | BPF_RSH: + emit_instr(ctx, srl, dst, dst, insn->imm & 0x1f); + break; + case BPF_ALU64 | BPF_LSH: + emit_instr(ctx, dsll_safe, dst, dst, insn->imm & 0x3f); + break; + case BPF_ALU | BPF_LSH: + emit_instr(ctx, sll, dst, dst, insn->imm & 0x1f); + break; + case BPF_ALU64 | BPF_ARSH: + emit_instr(ctx, dsra_safe, dst, dst, insn->imm & 0x3f); + break; + case BPF_ALU | BPF_ARSH: + emit_instr(ctx, sra, dst, dst, insn->imm & 0x1f); + break; + case BPF_ALU | BPF_MOV: + emit_instr(ctx, addiu, dst, MIPS_R_ZERO, insn->imm); + break; + case BPF_ALU | BPF_ADD: + emit_instr(ctx, addiu, dst, dst, insn->imm); + break; + case BPF_ALU | BPF_SUB: + emit_instr(ctx, addiu, dst, dst, -insn->imm); + break; + default: + return -EINVAL; + } + } else { + /* multi insn immediate case */ + if (BPF_OP(insn->code) == BPF_MOV) { + gen_imm_to_reg(insn, dst, ctx); + } else { + gen_imm_to_reg(insn, MIPS_R_AT, ctx); + switch (BPF_OP(insn->code) | BPF_CLASS(insn->code)) { + case BPF_ALU64 | BPF_AND: + case BPF_ALU | BPF_AND: + emit_instr(ctx, and, dst, dst, MIPS_R_AT); + break; + case BPF_ALU64 | BPF_OR: + case BPF_ALU | BPF_OR: + emit_instr(ctx, or, dst, dst, MIPS_R_AT); + break; + case BPF_ALU64 | BPF_XOR: + case BPF_ALU | BPF_XOR: + emit_instr(ctx, xor, dst, dst, MIPS_R_AT); + break; + case BPF_ALU64 | BPF_ADD: + emit_instr(ctx, daddu, dst, dst, MIPS_R_AT); + break; + case BPF_ALU64 | BPF_SUB: + emit_instr(ctx, dsubu, dst, dst, MIPS_R_AT); + break; + case BPF_ALU | BPF_ADD: + emit_instr(ctx, addu, dst, dst, MIPS_R_AT); + break; + case BPF_ALU | BPF_SUB: + emit_instr(ctx, subu, dst, dst, MIPS_R_AT); + break; + default: + return -EINVAL; + } + } + } + + return 0; +} + +static void emit_const_to_reg(struct jit_ctx *ctx, int dst, u64 value) +{ + if (value >= 0xffffffffffff8000ull || value < 0x8000ull) { + emit_instr(ctx, daddiu, dst, MIPS_R_ZERO, (int)value); + } else if (value >= 0xffffffff80000000ull || + (value < 0x80000000 && value > 0xffff)) { + emit_instr(ctx, lui, dst, (s32)(s16)(value >> 16)); + emit_instr(ctx, ori, dst, dst, (unsigned int)(value & 0xffff)); + } else { + int i; + bool seen_part = false; + int needed_shift = 0; + + for (i = 0; i < 4; i++) { + u64 part = (value >> (16 * (3 - i))) & 0xffff; + + if (seen_part && needed_shift > 0 && (part || i == 3)) { + emit_instr(ctx, dsll_safe, dst, dst, needed_shift); + needed_shift = 0; + } + if (part) { + if (i == 0 || (!seen_part && i < 3 && part < 0x8000)) { + emit_instr(ctx, lui, dst, (s32)(s16)part); + needed_shift = -16; + } else { + emit_instr(ctx, ori, dst, + seen_part ? dst : MIPS_R_ZERO, + (unsigned int)part); + } + seen_part = true; + } + if (seen_part) + needed_shift += 16; + } + } +} + +static int emit_bpf_tail_call(struct jit_ctx *ctx, int this_idx) +{ + int off, b_off; + int tcc_reg; + + ctx->flags |= EBPF_SEEN_TC; + /* + * if (index >= array->map.max_entries) + * goto out; + */ + off = offsetof(struct bpf_array, map.max_entries); + emit_instr(ctx, lwu, MIPS_R_T5, off, MIPS_R_A1); + emit_instr(ctx, sltu, MIPS_R_AT, MIPS_R_T5, MIPS_R_A2); + b_off = b_imm(this_idx + 1, ctx); + emit_instr(ctx, bne, MIPS_R_AT, MIPS_R_ZERO, b_off); + /* + * if (TCC-- < 0) + * goto out; + */ + /* Delay slot */ + tcc_reg = (ctx->flags & EBPF_TCC_IN_V1) ? MIPS_R_V1 : MIPS_R_S4; + emit_instr(ctx, daddiu, MIPS_R_T5, tcc_reg, -1); + b_off = b_imm(this_idx + 1, ctx); + emit_instr(ctx, bltz, tcc_reg, b_off); + /* + * prog = array->ptrs[index]; + * if (prog == NULL) + * goto out; + */ + /* Delay slot */ + emit_instr(ctx, dsll, MIPS_R_T8, MIPS_R_A2, 3); + emit_instr(ctx, daddu, MIPS_R_T8, MIPS_R_T8, MIPS_R_A1); + off = offsetof(struct bpf_array, ptrs); + emit_instr(ctx, ld, MIPS_R_AT, off, MIPS_R_T8); + b_off = b_imm(this_idx + 1, ctx); + emit_instr(ctx, beq, MIPS_R_AT, MIPS_R_ZERO, b_off); + /* Delay slot */ + emit_instr(ctx, nop); + + /* goto *(prog->bpf_func + 4); */ + off = offsetof(struct bpf_prog, bpf_func); + emit_instr(ctx, ld, MIPS_R_T9, off, MIPS_R_AT); + /* All systems are go... propagate TCC */ + emit_instr(ctx, daddu, MIPS_R_V1, MIPS_R_T5, MIPS_R_ZERO); + /* Skip first instruction (TCC initialization) */ + emit_instr(ctx, daddiu, MIPS_R_T9, MIPS_R_T9, 4); + return build_int_epilogue(ctx, MIPS_R_T9); +} + +static bool is_bad_offset(int b_off) +{ + return b_off > 0x1ffff || b_off < -0x20000; +} + +/* Returns the number of insn slots consumed. */ +static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, + int this_idx, int exit_idx) +{ + int src, dst, r, td, ts, mem_off, b_off; + bool need_swap, did_move, cmp_eq; + unsigned int target = 0; + u64 t64; + s64 t64s; + int bpf_op = BPF_OP(insn->code); + + switch (insn->code) { + case BPF_ALU64 | BPF_ADD | BPF_K: /* ALU64_IMM */ + case BPF_ALU64 | BPF_SUB | BPF_K: /* ALU64_IMM */ + case BPF_ALU64 | BPF_OR | BPF_K: /* ALU64_IMM */ + case BPF_ALU64 | BPF_AND | BPF_K: /* ALU64_IMM */ + case BPF_ALU64 | BPF_LSH | BPF_K: /* ALU64_IMM */ + case BPF_ALU64 | BPF_RSH | BPF_K: /* ALU64_IMM */ + case BPF_ALU64 | BPF_XOR | BPF_K: /* ALU64_IMM */ + case BPF_ALU64 | BPF_ARSH | BPF_K: /* ALU64_IMM */ + case BPF_ALU64 | BPF_MOV | BPF_K: /* ALU64_IMM */ + case BPF_ALU | BPF_MOV | BPF_K: /* ALU32_IMM */ + case BPF_ALU | BPF_ADD | BPF_K: /* ALU32_IMM */ + case BPF_ALU | BPF_SUB | BPF_K: /* ALU32_IMM */ + case BPF_ALU | BPF_OR | BPF_K: /* ALU64_IMM */ + case BPF_ALU | BPF_AND | BPF_K: /* ALU64_IMM */ + case BPF_ALU | BPF_LSH | BPF_K: /* ALU64_IMM */ + case BPF_ALU | BPF_RSH | BPF_K: /* ALU64_IMM */ + case BPF_ALU | BPF_XOR | BPF_K: /* ALU64_IMM */ + case BPF_ALU | BPF_ARSH | BPF_K: /* ALU64_IMM */ + r = gen_imm_insn(insn, ctx, this_idx); + if (r < 0) + return r; + break; + case BPF_ALU64 | BPF_MUL | BPF_K: /* ALU64_IMM */ + dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + if (dst < 0) + return dst; + if (get_reg_val_type(ctx, this_idx, insn->dst_reg) == REG_32BIT) + emit_instr(ctx, dinsu, dst, MIPS_R_ZERO, 32, 32); + if (insn->imm == 1) /* Mult by 1 is a nop */ + break; + gen_imm_to_reg(insn, MIPS_R_AT, ctx); + emit_instr(ctx, dmultu, MIPS_R_AT, dst); + emit_instr(ctx, mflo, dst); + break; + case BPF_ALU64 | BPF_NEG | BPF_K: /* ALU64_IMM */ + dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + if (dst < 0) + return dst; + if (get_reg_val_type(ctx, this_idx, insn->dst_reg) == REG_32BIT) + emit_instr(ctx, dinsu, dst, MIPS_R_ZERO, 32, 32); + emit_instr(ctx, dsubu, dst, MIPS_R_ZERO, dst); + break; + case BPF_ALU | BPF_MUL | BPF_K: /* ALU_IMM */ + dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + if (dst < 0) + return dst; + td = get_reg_val_type(ctx, this_idx, insn->dst_reg); + if (td == REG_64BIT || td == REG_32BIT_ZERO_EX) { + /* sign extend */ + emit_instr(ctx, sll, dst, dst, 0); + } + if (insn->imm == 1) /* Mult by 1 is a nop */ + break; + gen_imm_to_reg(insn, MIPS_R_AT, ctx); + emit_instr(ctx, multu, dst, MIPS_R_AT); + emit_instr(ctx, mflo, dst); + break; + case BPF_ALU | BPF_NEG | BPF_K: /* ALU_IMM */ + dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + if (dst < 0) + return dst; + td = get_reg_val_type(ctx, this_idx, insn->dst_reg); + if (td == REG_64BIT || td == REG_32BIT_ZERO_EX) { + /* sign extend */ + emit_instr(ctx, sll, dst, dst, 0); + } + emit_instr(ctx, subu, dst, MIPS_R_ZERO, dst); + break; + case BPF_ALU | BPF_DIV | BPF_K: /* ALU_IMM */ + case BPF_ALU | BPF_MOD | BPF_K: /* ALU_IMM */ + if (insn->imm == 0) + return -EINVAL; + dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + if (dst < 0) + return dst; + td = get_reg_val_type(ctx, this_idx, insn->dst_reg); + if (td == REG_64BIT || td == REG_32BIT_ZERO_EX) + /* sign extend */ + emit_instr(ctx, sll, dst, dst, 0); + if (insn->imm == 1) { + /* div by 1 is a nop, mod by 1 is zero */ + if (bpf_op == BPF_MOD) + emit_instr(ctx, addu, dst, MIPS_R_ZERO, MIPS_R_ZERO); + break; + } + gen_imm_to_reg(insn, MIPS_R_AT, ctx); + emit_instr(ctx, divu, dst, MIPS_R_AT); + if (bpf_op == BPF_DIV) + emit_instr(ctx, mflo, dst); + else + emit_instr(ctx, mfhi, dst); + break; + case BPF_ALU64 | BPF_DIV | BPF_K: /* ALU_IMM */ + case BPF_ALU64 | BPF_MOD | BPF_K: /* ALU_IMM */ + if (insn->imm == 0) + return -EINVAL; + dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + if (dst < 0) + return dst; + if (get_reg_val_type(ctx, this_idx, insn->dst_reg) == REG_32BIT) + emit_instr(ctx, dinsu, dst, MIPS_R_ZERO, 32, 32); + if (insn->imm == 1) { + /* div by 1 is a nop, mod by 1 is zero */ + if (bpf_op == BPF_MOD) + emit_instr(ctx, addu, dst, MIPS_R_ZERO, MIPS_R_ZERO); + break; + } + gen_imm_to_reg(insn, MIPS_R_AT, ctx); + emit_instr(ctx, ddivu, dst, MIPS_R_AT); + if (bpf_op == BPF_DIV) + emit_instr(ctx, mflo, dst); + else + emit_instr(ctx, mfhi, dst); + break; + case BPF_ALU64 | BPF_MOV | BPF_X: /* ALU64_REG */ + case BPF_ALU64 | BPF_ADD | BPF_X: /* ALU64_REG */ + case BPF_ALU64 | BPF_SUB | BPF_X: /* ALU64_REG */ + case BPF_ALU64 | BPF_XOR | BPF_X: /* ALU64_REG */ + case BPF_ALU64 | BPF_OR | BPF_X: /* ALU64_REG */ + case BPF_ALU64 | BPF_AND | BPF_X: /* ALU64_REG */ + case BPF_ALU64 | BPF_MUL | BPF_X: /* ALU64_REG */ + case BPF_ALU64 | BPF_DIV | BPF_X: /* ALU64_REG */ + case BPF_ALU64 | BPF_MOD | BPF_X: /* ALU64_REG */ + case BPF_ALU64 | BPF_LSH | BPF_X: /* ALU64_REG */ + case BPF_ALU64 | BPF_RSH | BPF_X: /* ALU64_REG */ + case BPF_ALU64 | BPF_ARSH | BPF_X: /* ALU64_REG */ + src = ebpf_to_mips_reg(ctx, insn, src_reg); + dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + if (src < 0 || dst < 0) + return -EINVAL; + if (get_reg_val_type(ctx, this_idx, insn->dst_reg) == REG_32BIT) + emit_instr(ctx, dinsu, dst, MIPS_R_ZERO, 32, 32); + did_move = false; + if (insn->src_reg == BPF_REG_10) { + if (bpf_op == BPF_MOV) { + emit_instr(ctx, daddiu, dst, MIPS_R_SP, MAX_BPF_STACK); + did_move = true; + } else { + emit_instr(ctx, daddiu, MIPS_R_AT, MIPS_R_SP, MAX_BPF_STACK); + src = MIPS_R_AT; + } + } else if (get_reg_val_type(ctx, this_idx, insn->src_reg) == REG_32BIT) { + int tmp_reg = MIPS_R_AT; + + if (bpf_op == BPF_MOV) { + tmp_reg = dst; + did_move = true; + } + emit_instr(ctx, daddu, tmp_reg, src, MIPS_R_ZERO); + emit_instr(ctx, dinsu, tmp_reg, MIPS_R_ZERO, 32, 32); + src = MIPS_R_AT; + } + switch (bpf_op) { + case BPF_MOV: + if (!did_move) + emit_instr(ctx, daddu, dst, src, MIPS_R_ZERO); + break; + case BPF_ADD: + emit_instr(ctx, daddu, dst, dst, src); + break; + case BPF_SUB: + emit_instr(ctx, dsubu, dst, dst, src); + break; + case BPF_XOR: + emit_instr(ctx, xor, dst, dst, src); + break; + case BPF_OR: + emit_instr(ctx, or, dst, dst, src); + break; + case BPF_AND: + emit_instr(ctx, and, dst, dst, src); + break; + case BPF_MUL: + emit_instr(ctx, dmultu, dst, src); + emit_instr(ctx, mflo, dst); + break; + case BPF_DIV: + case BPF_MOD: + emit_instr(ctx, ddivu, dst, src); + if (bpf_op == BPF_DIV) + emit_instr(ctx, mflo, dst); + else + emit_instr(ctx, mfhi, dst); + break; + case BPF_LSH: + emit_instr(ctx, dsllv, dst, dst, src); + break; + case BPF_RSH: + emit_instr(ctx, dsrlv, dst, dst, src); + break; + case BPF_ARSH: + emit_instr(ctx, dsrav, dst, dst, src); + break; + default: + pr_err("ALU64_REG NOT HANDLED\n"); + return -EINVAL; + } + break; + case BPF_ALU | BPF_MOV | BPF_X: /* ALU_REG */ + case BPF_ALU | BPF_ADD | BPF_X: /* ALU_REG */ + case BPF_ALU | BPF_SUB | BPF_X: /* ALU_REG */ + case BPF_ALU | BPF_XOR | BPF_X: /* ALU_REG */ + case BPF_ALU | BPF_OR | BPF_X: /* ALU_REG */ + case BPF_ALU | BPF_AND | BPF_X: /* ALU_REG */ + case BPF_ALU | BPF_MUL | BPF_X: /* ALU_REG */ + case BPF_ALU | BPF_DIV | BPF_X: /* ALU_REG */ + case BPF_ALU | BPF_MOD | BPF_X: /* ALU_REG */ + case BPF_ALU | BPF_LSH | BPF_X: /* ALU_REG */ + case BPF_ALU | BPF_RSH | BPF_X: /* ALU_REG */ + src = ebpf_to_mips_reg(ctx, insn, src_reg_no_fp); + dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + if (src < 0 || dst < 0) + return -EINVAL; + td = get_reg_val_type(ctx, this_idx, insn->dst_reg); + if (td == REG_64BIT || td == REG_32BIT_ZERO_EX) { + /* sign extend */ + emit_instr(ctx, sll, dst, dst, 0); + } + did_move = false; + ts = get_reg_val_type(ctx, this_idx, insn->src_reg); + if (ts == REG_64BIT || ts == REG_32BIT_ZERO_EX) { + int tmp_reg = MIPS_R_AT; + + if (bpf_op == BPF_MOV) { + tmp_reg = dst; + did_move = true; + } + /* sign extend */ + emit_instr(ctx, sll, tmp_reg, src, 0); + src = MIPS_R_AT; + } + switch (bpf_op) { + case BPF_MOV: + if (!did_move) + emit_instr(ctx, addu, dst, src, MIPS_R_ZERO); + break; + case BPF_ADD: + emit_instr(ctx, addu, dst, dst, src); + break; + case BPF_SUB: + emit_instr(ctx, subu, dst, dst, src); + break; + case BPF_XOR: + emit_instr(ctx, xor, dst, dst, src); + break; + case BPF_OR: + emit_instr(ctx, or, dst, dst, src); + break; + case BPF_AND: + emit_instr(ctx, and, dst, dst, src); + break; + case BPF_MUL: + emit_instr(ctx, mul, dst, dst, src); + break; + case BPF_DIV: + case BPF_MOD: + emit_instr(ctx, divu, dst, src); + if (bpf_op == BPF_DIV) + emit_instr(ctx, mflo, dst); + else + emit_instr(ctx, mfhi, dst); + break; + case BPF_LSH: + emit_instr(ctx, sllv, dst, dst, src); + break; + case BPF_RSH: + emit_instr(ctx, srlv, dst, dst, src); + break; + default: + pr_err("ALU_REG NOT HANDLED\n"); + return -EINVAL; + } + break; + case BPF_JMP | BPF_EXIT: + if (this_idx + 1 < exit_idx) { + b_off = b_imm(exit_idx, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + emit_instr(ctx, beq, MIPS_R_ZERO, MIPS_R_ZERO, b_off); + emit_instr(ctx, nop); + } + break; + case BPF_JMP | BPF_JEQ | BPF_K: /* JMP_IMM */ + case BPF_JMP | BPF_JNE | BPF_K: /* JMP_IMM */ + cmp_eq = (bpf_op == BPF_JEQ); + dst = ebpf_to_mips_reg(ctx, insn, dst_reg_fp_ok); + if (dst < 0) + return dst; + if (insn->imm == 0) { + src = MIPS_R_ZERO; + } else { + gen_imm_to_reg(insn, MIPS_R_AT, ctx); + src = MIPS_R_AT; + } + goto jeq_common; + case BPF_JMP | BPF_JEQ | BPF_X: /* JMP_REG */ + case BPF_JMP | BPF_JNE | BPF_X: + case BPF_JMP | BPF_JSLT | BPF_X: + case BPF_JMP | BPF_JSLE | BPF_X: + case BPF_JMP | BPF_JSGT | BPF_X: + case BPF_JMP | BPF_JSGE | BPF_X: + case BPF_JMP | BPF_JLT | BPF_X: + case BPF_JMP | BPF_JLE | BPF_X: + case BPF_JMP | BPF_JGT | BPF_X: + case BPF_JMP | BPF_JGE | BPF_X: + case BPF_JMP | BPF_JSET | BPF_X: + src = ebpf_to_mips_reg(ctx, insn, src_reg_no_fp); + dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + if (src < 0 || dst < 0) + return -EINVAL; + td = get_reg_val_type(ctx, this_idx, insn->dst_reg); + ts = get_reg_val_type(ctx, this_idx, insn->src_reg); + if (td == REG_32BIT && ts != REG_32BIT) { + emit_instr(ctx, sll, MIPS_R_AT, src, 0); + src = MIPS_R_AT; + } else if (ts == REG_32BIT && td != REG_32BIT) { + emit_instr(ctx, sll, MIPS_R_AT, dst, 0); + dst = MIPS_R_AT; + } + if (bpf_op == BPF_JSET) { + emit_instr(ctx, and, MIPS_R_AT, dst, src); + cmp_eq = false; + dst = MIPS_R_AT; + src = MIPS_R_ZERO; + } else if (bpf_op == BPF_JSGT || bpf_op == BPF_JSLE) { + emit_instr(ctx, dsubu, MIPS_R_AT, dst, src); + if ((insn + 1)->code == (BPF_JMP | BPF_EXIT) && insn->off == 1) { + b_off = b_imm(exit_idx, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + if (bpf_op == BPF_JSGT) + emit_instr(ctx, blez, MIPS_R_AT, b_off); + else + emit_instr(ctx, bgtz, MIPS_R_AT, b_off); + emit_instr(ctx, nop); + return 2; /* We consumed the exit. */ + } + b_off = b_imm(this_idx + insn->off + 1, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + if (bpf_op == BPF_JSGT) + emit_instr(ctx, bgtz, MIPS_R_AT, b_off); + else + emit_instr(ctx, blez, MIPS_R_AT, b_off); + emit_instr(ctx, nop); + break; + } else if (bpf_op == BPF_JSGE || bpf_op == BPF_JSLT) { + emit_instr(ctx, slt, MIPS_R_AT, dst, src); + cmp_eq = bpf_op == BPF_JSGE; + dst = MIPS_R_AT; + src = MIPS_R_ZERO; + } else if (bpf_op == BPF_JGT || bpf_op == BPF_JLE) { + /* dst or src could be AT */ + emit_instr(ctx, dsubu, MIPS_R_T8, dst, src); + emit_instr(ctx, sltu, MIPS_R_AT, dst, src); + /* SP known to be non-zero, movz becomes boolean not */ + emit_instr(ctx, movz, MIPS_R_T9, MIPS_R_SP, MIPS_R_T8); + emit_instr(ctx, movn, MIPS_R_T9, MIPS_R_ZERO, MIPS_R_T8); + emit_instr(ctx, or, MIPS_R_AT, MIPS_R_T9, MIPS_R_AT); + cmp_eq = bpf_op == BPF_JGT; + dst = MIPS_R_AT; + src = MIPS_R_ZERO; + } else if (bpf_op == BPF_JGE || bpf_op == BPF_JLT) { + emit_instr(ctx, sltu, MIPS_R_AT, dst, src); + cmp_eq = bpf_op == BPF_JGE; + dst = MIPS_R_AT; + src = MIPS_R_ZERO; + } else { /* JNE/JEQ case */ + cmp_eq = (bpf_op == BPF_JEQ); + } +jeq_common: + /* + * If the next insn is EXIT and we are jumping arround + * only it, invert the sense of the compare and + * conditionally jump to the exit. Poor man's branch + * chaining. + */ + if ((insn + 1)->code == (BPF_JMP | BPF_EXIT) && insn->off == 1) { + b_off = b_imm(exit_idx, ctx); + if (is_bad_offset(b_off)) { + target = j_target(ctx, exit_idx); + if (target == (unsigned int)-1) + return -E2BIG; + cmp_eq = !cmp_eq; + b_off = 4 * 3; + if (!(ctx->offsets[this_idx] & OFFSETS_B_CONV)) { + ctx->offsets[this_idx] |= OFFSETS_B_CONV; + ctx->long_b_conversion = 1; + } + } + + if (cmp_eq) + emit_instr(ctx, bne, dst, src, b_off); + else + emit_instr(ctx, beq, dst, src, b_off); + emit_instr(ctx, nop); + if (ctx->offsets[this_idx] & OFFSETS_B_CONV) { + emit_instr(ctx, j, target); + emit_instr(ctx, nop); + } + return 2; /* We consumed the exit. */ + } + b_off = b_imm(this_idx + insn->off + 1, ctx); + if (is_bad_offset(b_off)) { + target = j_target(ctx, this_idx + insn->off + 1); + if (target == (unsigned int)-1) + return -E2BIG; + cmp_eq = !cmp_eq; + b_off = 4 * 3; + if (!(ctx->offsets[this_idx] & OFFSETS_B_CONV)) { + ctx->offsets[this_idx] |= OFFSETS_B_CONV; + ctx->long_b_conversion = 1; + } + } + + if (cmp_eq) + emit_instr(ctx, beq, dst, src, b_off); + else + emit_instr(ctx, bne, dst, src, b_off); + emit_instr(ctx, nop); + if (ctx->offsets[this_idx] & OFFSETS_B_CONV) { + emit_instr(ctx, j, target); + emit_instr(ctx, nop); + } + break; + case BPF_JMP | BPF_JSGT | BPF_K: /* JMP_IMM */ + case BPF_JMP | BPF_JSGE | BPF_K: /* JMP_IMM */ + case BPF_JMP | BPF_JSLT | BPF_K: /* JMP_IMM */ + case BPF_JMP | BPF_JSLE | BPF_K: /* JMP_IMM */ + cmp_eq = (bpf_op == BPF_JSGE); + dst = ebpf_to_mips_reg(ctx, insn, dst_reg_fp_ok); + if (dst < 0) + return dst; + + if (insn->imm == 0) { + if ((insn + 1)->code == (BPF_JMP | BPF_EXIT) && insn->off == 1) { + b_off = b_imm(exit_idx, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + switch (bpf_op) { + case BPF_JSGT: + emit_instr(ctx, blez, dst, b_off); + break; + case BPF_JSGE: + emit_instr(ctx, bltz, dst, b_off); + break; + case BPF_JSLT: + emit_instr(ctx, bgez, dst, b_off); + break; + case BPF_JSLE: + emit_instr(ctx, bgtz, dst, b_off); + break; + } + emit_instr(ctx, nop); + return 2; /* We consumed the exit. */ + } + b_off = b_imm(this_idx + insn->off + 1, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + switch (bpf_op) { + case BPF_JSGT: + emit_instr(ctx, bgtz, dst, b_off); + break; + case BPF_JSGE: + emit_instr(ctx, bgez, dst, b_off); + break; + case BPF_JSLT: + emit_instr(ctx, bltz, dst, b_off); + break; + case BPF_JSLE: + emit_instr(ctx, blez, dst, b_off); + break; + } + emit_instr(ctx, nop); + break; + } + /* + * only "LT" compare available, so we must use imm + 1 + * to generate "GT" and imm -1 to generate LE + */ + if (bpf_op == BPF_JSGT) + t64s = insn->imm + 1; + else if (bpf_op == BPF_JSLE) + t64s = insn->imm + 1; + else + t64s = insn->imm; + + cmp_eq = bpf_op == BPF_JSGT || bpf_op == BPF_JSGE; + if (t64s >= S16_MIN && t64s <= S16_MAX) { + emit_instr(ctx, slti, MIPS_R_AT, dst, (int)t64s); + src = MIPS_R_AT; + dst = MIPS_R_ZERO; + goto jeq_common; + } + emit_const_to_reg(ctx, MIPS_R_AT, (u64)t64s); + emit_instr(ctx, slt, MIPS_R_AT, dst, MIPS_R_AT); + src = MIPS_R_AT; + dst = MIPS_R_ZERO; + goto jeq_common; + + case BPF_JMP | BPF_JGT | BPF_K: + case BPF_JMP | BPF_JGE | BPF_K: + case BPF_JMP | BPF_JLT | BPF_K: + case BPF_JMP | BPF_JLE | BPF_K: + cmp_eq = (bpf_op == BPF_JGE); + dst = ebpf_to_mips_reg(ctx, insn, dst_reg_fp_ok); + if (dst < 0) + return dst; + /* + * only "LT" compare available, so we must use imm + 1 + * to generate "GT" and imm -1 to generate LE + */ + if (bpf_op == BPF_JGT) + t64s = (u64)(u32)(insn->imm) + 1; + else if (bpf_op == BPF_JLE) + t64s = (u64)(u32)(insn->imm) + 1; + else + t64s = (u64)(u32)(insn->imm); + + cmp_eq = bpf_op == BPF_JGT || bpf_op == BPF_JGE; + + emit_const_to_reg(ctx, MIPS_R_AT, (u64)t64s); + emit_instr(ctx, sltu, MIPS_R_AT, dst, MIPS_R_AT); + src = MIPS_R_AT; + dst = MIPS_R_ZERO; + goto jeq_common; + + case BPF_JMP | BPF_JSET | BPF_K: /* JMP_IMM */ + dst = ebpf_to_mips_reg(ctx, insn, dst_reg_fp_ok); + if (dst < 0) + return dst; + + if (ctx->use_bbit_insns && hweight32((u32)insn->imm) == 1) { + if ((insn + 1)->code == (BPF_JMP | BPF_EXIT) && insn->off == 1) { + b_off = b_imm(exit_idx, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + emit_instr(ctx, bbit0, dst, ffs((u32)insn->imm) - 1, b_off); + emit_instr(ctx, nop); + return 2; /* We consumed the exit. */ + } + b_off = b_imm(this_idx + insn->off + 1, ctx); + if (is_bad_offset(b_off)) + return -E2BIG; + emit_instr(ctx, bbit1, dst, ffs((u32)insn->imm) - 1, b_off); + emit_instr(ctx, nop); + break; + } + t64 = (u32)insn->imm; + emit_const_to_reg(ctx, MIPS_R_AT, t64); + emit_instr(ctx, and, MIPS_R_AT, dst, MIPS_R_AT); + src = MIPS_R_AT; + dst = MIPS_R_ZERO; + cmp_eq = false; + goto jeq_common; + + case BPF_JMP | BPF_JA: + /* + * Prefer relative branch for easier debugging, but + * fall back if needed. + */ + b_off = b_imm(this_idx + insn->off + 1, ctx); + if (is_bad_offset(b_off)) { + target = j_target(ctx, this_idx + insn->off + 1); + if (target == (unsigned int)-1) + return -E2BIG; + emit_instr(ctx, j, target); + } else { + emit_instr(ctx, b, b_off); + } + emit_instr(ctx, nop); + break; + case BPF_LD | BPF_DW | BPF_IMM: + if (insn->src_reg != 0) + return -EINVAL; + dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + if (dst < 0) + return dst; + t64 = ((u64)(u32)insn->imm) | ((u64)(insn + 1)->imm << 32); + emit_const_to_reg(ctx, dst, t64); + return 2; /* Double slot insn */ + + case BPF_JMP | BPF_CALL: + ctx->flags |= EBPF_SAVE_RA; + t64s = (s64)insn->imm + (s64)__bpf_call_base; + emit_const_to_reg(ctx, MIPS_R_T9, (u64)t64s); + emit_instr(ctx, jalr, MIPS_R_RA, MIPS_R_T9); + /* delay slot */ + emit_instr(ctx, nop); + break; + + case BPF_JMP | BPF_TAIL_CALL: + if (emit_bpf_tail_call(ctx, this_idx)) + return -EINVAL; + break; + + case BPF_ALU | BPF_END | BPF_FROM_BE: + case BPF_ALU | BPF_END | BPF_FROM_LE: + dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + if (dst < 0) + return dst; + td = get_reg_val_type(ctx, this_idx, insn->dst_reg); + if (insn->imm == 64 && td == REG_32BIT) + emit_instr(ctx, dinsu, dst, MIPS_R_ZERO, 32, 32); + + if (insn->imm != 64 && + (td == REG_64BIT || td == REG_32BIT_ZERO_EX)) { + /* sign extend */ + emit_instr(ctx, sll, dst, dst, 0); + } + +#ifdef __BIG_ENDIAN + need_swap = (BPF_SRC(insn->code) == BPF_FROM_LE); +#else + need_swap = (BPF_SRC(insn->code) == BPF_FROM_BE); +#endif + if (insn->imm == 16) { + if (need_swap) + emit_instr(ctx, wsbh, dst, dst); + emit_instr(ctx, andi, dst, dst, 0xffff); + } else if (insn->imm == 32) { + if (need_swap) { + emit_instr(ctx, wsbh, dst, dst); + emit_instr(ctx, rotr, dst, dst, 16); + } + } else { /* 64-bit*/ + if (need_swap) { + emit_instr(ctx, dsbh, dst, dst); + emit_instr(ctx, dshd, dst, dst); + } + } + break; + + case BPF_ST | BPF_NOSPEC: /* speculation barrier */ + break; + + case BPF_ST | BPF_B | BPF_MEM: + case BPF_ST | BPF_H | BPF_MEM: + case BPF_ST | BPF_W | BPF_MEM: + case BPF_ST | BPF_DW | BPF_MEM: + if (insn->dst_reg == BPF_REG_10) { + ctx->flags |= EBPF_SEEN_FP; + dst = MIPS_R_SP; + mem_off = insn->off + MAX_BPF_STACK; + } else { + dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + if (dst < 0) + return dst; + mem_off = insn->off; + } + gen_imm_to_reg(insn, MIPS_R_AT, ctx); + switch (BPF_SIZE(insn->code)) { + case BPF_B: + emit_instr(ctx, sb, MIPS_R_AT, mem_off, dst); + break; + case BPF_H: + emit_instr(ctx, sh, MIPS_R_AT, mem_off, dst); + break; + case BPF_W: + emit_instr(ctx, sw, MIPS_R_AT, mem_off, dst); + break; + case BPF_DW: + emit_instr(ctx, sd, MIPS_R_AT, mem_off, dst); + break; + } + break; + + case BPF_LDX | BPF_B | BPF_MEM: + case BPF_LDX | BPF_H | BPF_MEM: + case BPF_LDX | BPF_W | BPF_MEM: + case BPF_LDX | BPF_DW | BPF_MEM: + if (insn->src_reg == BPF_REG_10) { + ctx->flags |= EBPF_SEEN_FP; + src = MIPS_R_SP; + mem_off = insn->off + MAX_BPF_STACK; + } else { + src = ebpf_to_mips_reg(ctx, insn, src_reg_no_fp); + if (src < 0) + return src; + mem_off = insn->off; + } + dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + if (dst < 0) + return dst; + switch (BPF_SIZE(insn->code)) { + case BPF_B: + emit_instr(ctx, lbu, dst, mem_off, src); + break; + case BPF_H: + emit_instr(ctx, lhu, dst, mem_off, src); + break; + case BPF_W: + emit_instr(ctx, lw, dst, mem_off, src); + break; + case BPF_DW: + emit_instr(ctx, ld, dst, mem_off, src); + break; + } + break; + + case BPF_STX | BPF_B | BPF_MEM: + case BPF_STX | BPF_H | BPF_MEM: + case BPF_STX | BPF_W | BPF_MEM: + case BPF_STX | BPF_DW | BPF_MEM: + case BPF_STX | BPF_W | BPF_XADD: + case BPF_STX | BPF_DW | BPF_XADD: + if (insn->dst_reg == BPF_REG_10) { + ctx->flags |= EBPF_SEEN_FP; + dst = MIPS_R_SP; + mem_off = insn->off + MAX_BPF_STACK; + } else { + dst = ebpf_to_mips_reg(ctx, insn, dst_reg); + if (dst < 0) + return dst; + mem_off = insn->off; + } + src = ebpf_to_mips_reg(ctx, insn, src_reg_no_fp); + if (src < 0) + return src; + if (BPF_MODE(insn->code) == BPF_XADD) { + switch (BPF_SIZE(insn->code)) { + case BPF_W: + if (get_reg_val_type(ctx, this_idx, insn->src_reg) == REG_32BIT) { + emit_instr(ctx, sll, MIPS_R_AT, src, 0); + src = MIPS_R_AT; + } + emit_instr(ctx, ll, MIPS_R_T8, mem_off, dst); + emit_instr(ctx, addu, MIPS_R_T8, MIPS_R_T8, src); + emit_instr(ctx, sc, MIPS_R_T8, mem_off, dst); + /* + * On failure back up to LL (-4 + * instructions of 4 bytes each + */ + emit_instr(ctx, beq, MIPS_R_T8, MIPS_R_ZERO, -4 * 4); + emit_instr(ctx, nop); + break; + case BPF_DW: + if (get_reg_val_type(ctx, this_idx, insn->src_reg) == REG_32BIT) { + emit_instr(ctx, daddu, MIPS_R_AT, src, MIPS_R_ZERO); + emit_instr(ctx, dinsu, MIPS_R_AT, MIPS_R_ZERO, 32, 32); + src = MIPS_R_AT; + } + emit_instr(ctx, lld, MIPS_R_T8, mem_off, dst); + emit_instr(ctx, daddu, MIPS_R_T8, MIPS_R_T8, src); + emit_instr(ctx, scd, MIPS_R_T8, mem_off, dst); + emit_instr(ctx, beq, MIPS_R_T8, MIPS_R_ZERO, -4 * 4); + emit_instr(ctx, nop); + break; + } + } else { /* BPF_MEM */ + switch (BPF_SIZE(insn->code)) { + case BPF_B: + emit_instr(ctx, sb, src, mem_off, dst); + break; + case BPF_H: + emit_instr(ctx, sh, src, mem_off, dst); + break; + case BPF_W: + emit_instr(ctx, sw, src, mem_off, dst); + break; + case BPF_DW: + if (get_reg_val_type(ctx, this_idx, insn->src_reg) == REG_32BIT) { + emit_instr(ctx, daddu, MIPS_R_AT, src, MIPS_R_ZERO); + emit_instr(ctx, dinsu, MIPS_R_AT, MIPS_R_ZERO, 32, 32); + src = MIPS_R_AT; + } + emit_instr(ctx, sd, src, mem_off, dst); + break; + } + } + break; + + default: + pr_err("NOT HANDLED %d - (%02x)\n", + this_idx, (unsigned int)insn->code); + return -EINVAL; + } + return 1; +} + +#define RVT_VISITED_MASK 0xc000000000000000ull +#define RVT_FALL_THROUGH 0x4000000000000000ull +#define RVT_BRANCH_TAKEN 0x8000000000000000ull +#define RVT_DONE (RVT_FALL_THROUGH | RVT_BRANCH_TAKEN) + +static int build_int_body(struct jit_ctx *ctx) +{ + const struct bpf_prog *prog = ctx->skf; + const struct bpf_insn *insn; + int i, r; + + for (i = 0; i < prog->len; ) { + insn = prog->insnsi + i; + if ((ctx->reg_val_types[i] & RVT_VISITED_MASK) == 0) { + /* dead instruction, don't emit it. */ + i++; + continue; + } + + if (ctx->target == NULL) + ctx->offsets[i] = (ctx->offsets[i] & OFFSETS_B_CONV) | (ctx->idx * 4); + + r = build_one_insn(insn, ctx, i, prog->len); + if (r < 0) + return r; + i += r; + } + /* epilogue offset */ + if (ctx->target == NULL) + ctx->offsets[i] = ctx->idx * 4; + + /* + * All exits have an offset of the epilogue, some offsets may + * not have been set due to banch-around threading, so set + * them now. + */ + if (ctx->target == NULL) + for (i = 0; i < prog->len; i++) { + insn = prog->insnsi + i; + if (insn->code == (BPF_JMP | BPF_EXIT)) + ctx->offsets[i] = ctx->idx * 4; + } + return 0; +} + +/* return the last idx processed, or negative for error */ +static int reg_val_propagate_range(struct jit_ctx *ctx, u64 initial_rvt, + int start_idx, bool follow_taken) +{ + const struct bpf_prog *prog = ctx->skf; + const struct bpf_insn *insn; + u64 exit_rvt = initial_rvt; + u64 *rvt = ctx->reg_val_types; + int idx; + int reg; + + for (idx = start_idx; idx < prog->len; idx++) { + rvt[idx] = (rvt[idx] & RVT_VISITED_MASK) | exit_rvt; + insn = prog->insnsi + idx; + switch (BPF_CLASS(insn->code)) { + case BPF_ALU: + switch (BPF_OP(insn->code)) { + case BPF_ADD: + case BPF_SUB: + case BPF_MUL: + case BPF_DIV: + case BPF_OR: + case BPF_AND: + case BPF_LSH: + case BPF_RSH: + case BPF_NEG: + case BPF_MOD: + case BPF_XOR: + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT); + break; + case BPF_MOV: + if (BPF_SRC(insn->code)) { + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT); + } else { + /* IMM to REG move*/ + if (insn->imm >= 0) + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT_POS); + else + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT); + } + break; + case BPF_END: + if (insn->imm == 64) + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT); + else if (insn->imm == 32) + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT); + else /* insn->imm == 16 */ + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT_POS); + break; + } + rvt[idx] |= RVT_DONE; + break; + case BPF_ALU64: + switch (BPF_OP(insn->code)) { + case BPF_MOV: + if (BPF_SRC(insn->code)) { + /* REG to REG move*/ + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT); + } else { + /* IMM to REG move*/ + if (insn->imm >= 0) + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT_POS); + else + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT_32BIT); + } + break; + default: + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT); + } + rvt[idx] |= RVT_DONE; + break; + case BPF_LD: + switch (BPF_SIZE(insn->code)) { + case BPF_DW: + if (BPF_MODE(insn->code) == BPF_IMM) { + s64 val; + + val = (s64)((u32)insn->imm | ((u64)(insn + 1)->imm << 32)); + if (val > 0 && val <= S32_MAX) + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT_POS); + else if (val >= S32_MIN && val <= S32_MAX) + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT_32BIT); + else + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT); + rvt[idx] |= RVT_DONE; + idx++; + } else { + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT); + } + break; + case BPF_B: + case BPF_H: + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT_POS); + break; + case BPF_W: + if (BPF_MODE(insn->code) == BPF_IMM) + set_reg_val_type(&exit_rvt, insn->dst_reg, + insn->imm >= 0 ? REG_32BIT_POS : REG_32BIT); + else + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT); + break; + } + rvt[idx] |= RVT_DONE; + break; + case BPF_LDX: + switch (BPF_SIZE(insn->code)) { + case BPF_DW: + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_64BIT); + break; + case BPF_B: + case BPF_H: + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT_POS); + break; + case BPF_W: + set_reg_val_type(&exit_rvt, insn->dst_reg, REG_32BIT); + break; + } + rvt[idx] |= RVT_DONE; + break; + case BPF_JMP: + switch (BPF_OP(insn->code)) { + case BPF_EXIT: + rvt[idx] = RVT_DONE | exit_rvt; + rvt[prog->len] = exit_rvt; + return idx; + case BPF_JA: + rvt[idx] |= RVT_DONE; + idx += insn->off; + break; + case BPF_JEQ: + case BPF_JGT: + case BPF_JGE: + case BPF_JLT: + case BPF_JLE: + case BPF_JSET: + case BPF_JNE: + case BPF_JSGT: + case BPF_JSGE: + case BPF_JSLT: + case BPF_JSLE: + if (follow_taken) { + rvt[idx] |= RVT_BRANCH_TAKEN; + idx += insn->off; + follow_taken = false; + } else { + rvt[idx] |= RVT_FALL_THROUGH; + } + break; + case BPF_CALL: + set_reg_val_type(&exit_rvt, BPF_REG_0, REG_64BIT); + /* Upon call return, argument registers are clobbered. */ + for (reg = BPF_REG_0; reg <= BPF_REG_5; reg++) + set_reg_val_type(&exit_rvt, reg, REG_64BIT); + + rvt[idx] |= RVT_DONE; + break; + default: + WARN(1, "Unhandled BPF_JMP case.\n"); + rvt[idx] |= RVT_DONE; + break; + } + break; + default: + rvt[idx] |= RVT_DONE; + break; + } + } + return idx; +} + +/* + * Track the value range (i.e. 32-bit vs. 64-bit) of each register at + * each eBPF insn. This allows unneeded sign and zero extension + * operations to be omitted. + * + * Doesn't handle yet confluence of control paths with conflicting + * ranges, but it is good enough for most sane code. + */ +static int reg_val_propagate(struct jit_ctx *ctx) +{ + const struct bpf_prog *prog = ctx->skf; + u64 exit_rvt; + int reg; + int i; + + /* + * 11 registers * 3 bits/reg leaves top bits free for other + * uses. Bit-62..63 used to see if we have visited an insn. + */ + exit_rvt = 0; + + /* Upon entry, argument registers are 64-bit. */ + for (reg = BPF_REG_1; reg <= BPF_REG_5; reg++) + set_reg_val_type(&exit_rvt, reg, REG_64BIT); + + /* + * First follow all conditional branches on the fall-through + * edge of control flow.. + */ + reg_val_propagate_range(ctx, exit_rvt, 0, false); +restart_search: + /* + * Then repeatedly find the first conditional branch where + * both edges of control flow have not been taken, and follow + * the branch taken edge. We will end up restarting the + * search once per conditional branch insn. + */ + for (i = 0; i < prog->len; i++) { + u64 rvt = ctx->reg_val_types[i]; + + if ((rvt & RVT_VISITED_MASK) == RVT_DONE || + (rvt & RVT_VISITED_MASK) == 0) + continue; + if ((rvt & RVT_VISITED_MASK) == RVT_FALL_THROUGH) { + reg_val_propagate_range(ctx, rvt & ~RVT_VISITED_MASK, i, true); + } else { /* RVT_BRANCH_TAKEN */ + WARN(1, "Unexpected RVT_BRANCH_TAKEN case.\n"); + reg_val_propagate_range(ctx, rvt & ~RVT_VISITED_MASK, i, false); + } + goto restart_search; + } + /* + * Eventually all conditional branches have been followed on + * both branches and we are done. Any insn that has not been + * visited at this point is dead. + */ + + return 0; +} + +static void jit_fill_hole(void *area, unsigned int size) +{ + u32 *p; + + /* We are guaranteed to have aligned memory. */ + for (p = area; size >= sizeof(u32); size -= sizeof(u32)) + uasm_i_break(&p, BRK_BUG); /* Increments p */ +} + +struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) +{ + struct bpf_prog *orig_prog = prog; + bool tmp_blinded = false; + struct bpf_prog *tmp; + struct bpf_binary_header *header = NULL; + struct jit_ctx ctx; + unsigned int image_size; + u8 *image_ptr; + + if (!prog->jit_requested || !cpu_has_mips64r2) + return prog; + + tmp = bpf_jit_blind_constants(prog); + /* If blinding was requested and we failed during blinding, + * we must fall back to the interpreter. + */ + if (IS_ERR(tmp)) + return orig_prog; + if (tmp != prog) { + tmp_blinded = true; + prog = tmp; + } + + memset(&ctx, 0, sizeof(ctx)); + + preempt_disable(); + switch (current_cpu_type()) { + case CPU_CAVIUM_OCTEON: + case CPU_CAVIUM_OCTEON_PLUS: + case CPU_CAVIUM_OCTEON2: + case CPU_CAVIUM_OCTEON3: + ctx.use_bbit_insns = 1; + break; + default: + ctx.use_bbit_insns = 0; + } + preempt_enable(); + + ctx.offsets = kcalloc(prog->len + 1, sizeof(*ctx.offsets), GFP_KERNEL); + if (ctx.offsets == NULL) + goto out_err; + + ctx.reg_val_types = kcalloc(prog->len + 1, sizeof(*ctx.reg_val_types), GFP_KERNEL); + if (ctx.reg_val_types == NULL) + goto out_err; + + ctx.skf = prog; + + if (reg_val_propagate(&ctx)) + goto out_err; + + /* + * First pass discovers used resources and instruction offsets + * assuming short branches are used. + */ + if (build_int_body(&ctx)) + goto out_err; + + /* + * If no calls are made (EBPF_SAVE_RA), then tail call count + * in $v1, else we must save in n$s4. + */ + if (ctx.flags & EBPF_SEEN_TC) { + if (ctx.flags & EBPF_SAVE_RA) + ctx.flags |= EBPF_SAVE_S4; + else + ctx.flags |= EBPF_TCC_IN_V1; + } + + /* + * Second pass generates offsets, if any branches are out of + * range a jump-around long sequence is generated, and we have + * to try again from the beginning to generate the new + * offsets. This is done until no additional conversions are + * necessary. + */ + do { + ctx.idx = 0; + ctx.gen_b_offsets = 1; + ctx.long_b_conversion = 0; + if (gen_int_prologue(&ctx)) + goto out_err; + if (build_int_body(&ctx)) + goto out_err; + if (build_int_epilogue(&ctx, MIPS_R_RA)) + goto out_err; + } while (ctx.long_b_conversion); + + image_size = 4 * ctx.idx; + + header = bpf_jit_binary_alloc(image_size, &image_ptr, + sizeof(u32), jit_fill_hole); + if (header == NULL) + goto out_err; + + ctx.target = (u32 *)image_ptr; + + /* Third pass generates the code */ + ctx.idx = 0; + if (gen_int_prologue(&ctx)) + goto out_err; + if (build_int_body(&ctx)) + goto out_err; + if (build_int_epilogue(&ctx, MIPS_R_RA)) + goto out_err; + + /* Update the icache */ + flush_icache_range((unsigned long)ctx.target, + (unsigned long)&ctx.target[ctx.idx]); + + if (bpf_jit_enable > 1) + /* Dump JIT code */ + 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_normal: + if (tmp_blinded) + bpf_jit_prog_release_other(prog, prog == orig_prog ? + tmp : orig_prog); + kfree(ctx.offsets); + kfree(ctx.reg_val_types); + + return prog; + +out_err: + prog = orig_prog; + if (header) + bpf_jit_binary_free(header); + goto out_normal; +} |