diff options
Diffstat (limited to 'arch/mips/net/bpf_jit.c')
| -rw-r--r-- | arch/mips/net/bpf_jit.c | 1299 |
1 files changed, 0 insertions, 1299 deletions
diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c deleted file mode 100644 index cb6d22439f71..000000000000 --- a/arch/mips/net/bpf_jit.c +++ /dev/null @@ -1,1299 +0,0 @@ -/* - * 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(sizeof_field(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(sizeof_field(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(sizeof_field(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(sizeof_field(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(sizeof_field(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(sizeof_field(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(sizeof_field(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: - ctx->flags |= SEEN_SKB | SEEN_A; - BUILD_BUG_ON(sizeof_field(struct sk_buff, - vlan_tci) != 2); - off = offsetof(struct sk_buff, vlan_tci); - emit_half_load_unsigned(r_A, r_skb, off, ctx); - break; - case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT: - ctx->flags |= SEEN_SKB | SEEN_A; - emit_load_byte(r_A, r_skb, PKT_VLAN_PRESENT_OFFSET(), ctx); - if (PKT_VLAN_PRESENT_BIT) - emit_srl(r_A, r_A, PKT_VLAN_PRESENT_BIT, ctx); - if (PKT_VLAN_PRESENT_BIT < 7) - emit_andi(r_A, r_A, 1, 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(sizeof_field(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); -} |