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linux/arch/mips/net/ebpf_jit.c

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/*
* 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
* @tmp_offset: eBPF $sp offset to 8-byte temporary memory
* @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;
int tmp_offset;
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->tmp_offset = 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;
int r0 = MIPS_R_V0;
if (dest_reg == MIPS_R_RA &&
get_reg_val_type(ctx, prog->len, BPF_REG_0) == REG_32BIT_ZERO_EX)
/* Don't let zero extended value escape. */
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 * __must_check
ool_skb_header_pointer(const struct sk_buff *skb, int offset,
int len, void *buffer)
{
return skb_header_pointer(skb, offset, len, buffer);
}
static int size_to_len(const struct bpf_insn *insn)
{
switch (BPF_SIZE(insn->code)) {
case BPF_B:
return 1;
case BPF_H:
return 2;
case BPF_W:
return 4;
case BPF_DW:
return 8;
}
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;
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 */
emit_instr(ctx, daddiu, MIPS_R_T5,
(ctx->flags & EBPF_TCC_IN_V1) ? MIPS_R_V1 : MIPS_R_S4, -1);
b_off = b_imm(this_idx + 1, ctx);
emit_instr(ctx, bltz, MIPS_R_T5, 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_LD | BPF_B | BPF_ABS:
case BPF_LD | BPF_H | BPF_ABS:
case BPF_LD | BPF_W | BPF_ABS:
case BPF_LD | BPF_DW | BPF_ABS:
ctx->flags |= EBPF_SAVE_RA;
gen_imm_to_reg(insn, MIPS_R_A1, ctx);
emit_instr(ctx, addiu, MIPS_R_A2, MIPS_R_ZERO, size_to_len(insn));
if (insn->imm < 0) {
emit_const_to_reg(ctx, MIPS_R_T9, (u64)bpf_internal_load_pointer_neg_helper);
} else {
emit_const_to_reg(ctx, MIPS_R_T9, (u64)ool_skb_header_pointer);
emit_instr(ctx, daddiu, MIPS_R_A3, MIPS_R_SP, ctx->tmp_offset);
}
goto ld_skb_common;
case BPF_LD | BPF_B | BPF_IND:
case BPF_LD | BPF_H | BPF_IND:
case BPF_LD | BPF_W | BPF_IND:
case BPF_LD | BPF_DW | BPF_IND:
ctx->flags |= EBPF_SAVE_RA;
src = ebpf_to_mips_reg(ctx, insn, src_reg_no_fp);
if (src < 0)
return src;
ts = get_reg_val_type(ctx, this_idx, insn->src_reg);
if (ts == REG_32BIT_ZERO_EX) {
/* sign extend */
emit_instr(ctx, sll, MIPS_R_A1, src, 0);
src = MIPS_R_A1;
}
if (insn->imm >= S16_MIN && insn->imm <= S16_MAX) {
emit_instr(ctx, daddiu, MIPS_R_A1, src, insn->imm);
} else {
gen_imm_to_reg(insn, MIPS_R_AT, ctx);
emit_instr(ctx, daddu, MIPS_R_A1, MIPS_R_AT, src);
}
/* truncate to 32-bit int */
emit_instr(ctx, sll, MIPS_R_A1, MIPS_R_A1, 0);
emit_instr(ctx, daddiu, MIPS_R_A3, MIPS_R_SP, ctx->tmp_offset);
emit_instr(ctx, slt, MIPS_R_AT, MIPS_R_A1, MIPS_R_ZERO);
emit_const_to_reg(ctx, MIPS_R_T8, (u64)bpf_internal_load_pointer_neg_helper);
emit_const_to_reg(ctx, MIPS_R_T9, (u64)ool_skb_header_pointer);
emit_instr(ctx, addiu, MIPS_R_A2, MIPS_R_ZERO, size_to_len(insn));
emit_instr(ctx, movn, MIPS_R_T9, MIPS_R_T8, MIPS_R_AT);
ld_skb_common:
emit_instr(ctx, jalr, MIPS_R_RA, MIPS_R_T9);
/* delay slot move */
emit_instr(ctx, daddu, MIPS_R_A0, MIPS_R_S0, MIPS_R_ZERO);
/* Check the error value */
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;
if (!(ctx->offsets[this_idx] & OFFSETS_B_CONV)) {
ctx->offsets[this_idx] |= OFFSETS_B_CONV;
ctx->long_b_conversion = 1;
}
emit_instr(ctx, bne, MIPS_R_V0, MIPS_R_ZERO, 4 * 3);
emit_instr(ctx, nop);
emit_instr(ctx, j, target);
emit_instr(ctx, nop);
} else {
emit_instr(ctx, beq, MIPS_R_V0, MIPS_R_ZERO, b_off);
emit_instr(ctx, nop);
}
#ifdef __BIG_ENDIAN
need_swap = false;
#else
need_swap = true;
#endif
dst = MIPS_R_V0;
switch (BPF_SIZE(insn->code)) {
case BPF_B:
emit_instr(ctx, lbu, dst, 0, MIPS_R_V0);
break;
case BPF_H:
emit_instr(ctx, lhu, dst, 0, MIPS_R_V0);
if (need_swap)
emit_instr(ctx, wsbh, dst, dst);
break;
case BPF_W:
emit_instr(ctx, lw, dst, 0, MIPS_R_V0);
if (need_swap) {
emit_instr(ctx, wsbh, dst, dst);
emit_instr(ctx, rotr, dst, dst, 16);
}
break;
case BPF_DW:
emit_instr(ctx, ld, dst, 0, MIPS_R_V0);
if (need_swap) {
emit_instr(ctx, dsbh, dst, dst);
emit_instr(ctx, dshd, dst, dst);
}
break;
}
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_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 * sizeof(u32)));
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;
}
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