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linux-zen-desktop/arch/loongarch/net/bpf_jit.c

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Initial commit
2023-08-30 17:31:07 +02:00
// SPDX-License-Identifier: GPL-2.0-only
/*
* BPF JIT compiler for LoongArch
*
* Copyright (C) 2022 Loongson Technology Corporation Limited
*/
#include "bpf_jit.h"
#define REG_TCC LOONGARCH_GPR_A6
#define TCC_SAVED LOONGARCH_GPR_S5
#define SAVE_RA BIT(0)
#define SAVE_TCC BIT(1)
static const int regmap[] = {
/* return value from in-kernel function, and exit value for eBPF program */
[BPF_REG_0] = LOONGARCH_GPR_A5,
/* arguments from eBPF program to in-kernel function */
[BPF_REG_1] = LOONGARCH_GPR_A0,
[BPF_REG_2] = LOONGARCH_GPR_A1,
[BPF_REG_3] = LOONGARCH_GPR_A2,
[BPF_REG_4] = LOONGARCH_GPR_A3,
[BPF_REG_5] = LOONGARCH_GPR_A4,
/* callee saved registers that in-kernel function will preserve */
[BPF_REG_6] = LOONGARCH_GPR_S0,
[BPF_REG_7] = LOONGARCH_GPR_S1,
[BPF_REG_8] = LOONGARCH_GPR_S2,
[BPF_REG_9] = LOONGARCH_GPR_S3,
/* read-only frame pointer to access stack */
[BPF_REG_FP] = LOONGARCH_GPR_S4,
/* temporary register for blinding constants */
[BPF_REG_AX] = LOONGARCH_GPR_T0,
};
static void mark_call(struct jit_ctx *ctx)
{
ctx->flags |= SAVE_RA;
}
static void mark_tail_call(struct jit_ctx *ctx)
{
ctx->flags |= SAVE_TCC;
}
static bool seen_call(struct jit_ctx *ctx)
{
return (ctx->flags & SAVE_RA);
}
static bool seen_tail_call(struct jit_ctx *ctx)
{
return (ctx->flags & SAVE_TCC);
}
static u8 tail_call_reg(struct jit_ctx *ctx)
{
if (seen_call(ctx))
return TCC_SAVED;
return REG_TCC;
}
/*
* eBPF prog stack layout:
*
* high
* original $sp ------------> +-------------------------+ <--LOONGARCH_GPR_FP
* | $ra |
* +-------------------------+
* | $fp |
* +-------------------------+
* | $s0 |
* +-------------------------+
* | $s1 |
* +-------------------------+
* | $s2 |
* +-------------------------+
* | $s3 |
* +-------------------------+
* | $s4 |
* +-------------------------+
* | $s5 |
* +-------------------------+ <--BPF_REG_FP
* | prog->aux->stack_depth |
* | (optional) |
* current $sp -------------> +-------------------------+
* low
*/
static void build_prologue(struct jit_ctx *ctx)
{
int stack_adjust = 0, store_offset, bpf_stack_adjust;
bpf_stack_adjust = round_up(ctx->prog->aux->stack_depth, 16);
/* To store ra, fp, s0, s1, s2, s3, s4 and s5. */
stack_adjust += sizeof(long) * 8;
stack_adjust = round_up(stack_adjust, 16);
stack_adjust += bpf_stack_adjust;
/*
* First instruction initializes the tail call count (TCC).
* On tail call we skip this instruction, and the TCC is
* passed in REG_TCC from the caller.
*/
emit_insn(ctx, addid, REG_TCC, LOONGARCH_GPR_ZERO, MAX_TAIL_CALL_CNT);
emit_insn(ctx, addid, LOONGARCH_GPR_SP, LOONGARCH_GPR_SP, -stack_adjust);
store_offset = stack_adjust - sizeof(long);
emit_insn(ctx, std, LOONGARCH_GPR_RA, LOONGARCH_GPR_SP, store_offset);
store_offset -= sizeof(long);
emit_insn(ctx, std, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, store_offset);
store_offset -= sizeof(long);
emit_insn(ctx, std, LOONGARCH_GPR_S0, LOONGARCH_GPR_SP, store_offset);
store_offset -= sizeof(long);
emit_insn(ctx, std, LOONGARCH_GPR_S1, LOONGARCH_GPR_SP, store_offset);
store_offset -= sizeof(long);
emit_insn(ctx, std, LOONGARCH_GPR_S2, LOONGARCH_GPR_SP, store_offset);
store_offset -= sizeof(long);
emit_insn(ctx, std, LOONGARCH_GPR_S3, LOONGARCH_GPR_SP, store_offset);
store_offset -= sizeof(long);
emit_insn(ctx, std, LOONGARCH_GPR_S4, LOONGARCH_GPR_SP, store_offset);
store_offset -= sizeof(long);
emit_insn(ctx, std, LOONGARCH_GPR_S5, LOONGARCH_GPR_SP, store_offset);
emit_insn(ctx, addid, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, stack_adjust);
if (bpf_stack_adjust)
emit_insn(ctx, addid, regmap[BPF_REG_FP], LOONGARCH_GPR_SP, bpf_stack_adjust);
/*
* Program contains calls and tail calls, so REG_TCC need
* to be saved across calls.
*/
if (seen_tail_call(ctx) && seen_call(ctx))
move_reg(ctx, TCC_SAVED, REG_TCC);
ctx->stack_size = stack_adjust;
}
static void __build_epilogue(struct jit_ctx *ctx, bool is_tail_call)
{
int stack_adjust = ctx->stack_size;
int load_offset;
load_offset = stack_adjust - sizeof(long);
emit_insn(ctx, ldd, LOONGARCH_GPR_RA, LOONGARCH_GPR_SP, load_offset);
load_offset -= sizeof(long);
emit_insn(ctx, ldd, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, load_offset);
load_offset -= sizeof(long);
emit_insn(ctx, ldd, LOONGARCH_GPR_S0, LOONGARCH_GPR_SP, load_offset);
load_offset -= sizeof(long);
emit_insn(ctx, ldd, LOONGARCH_GPR_S1, LOONGARCH_GPR_SP, load_offset);
load_offset -= sizeof(long);
emit_insn(ctx, ldd, LOONGARCH_GPR_S2, LOONGARCH_GPR_SP, load_offset);
load_offset -= sizeof(long);
emit_insn(ctx, ldd, LOONGARCH_GPR_S3, LOONGARCH_GPR_SP, load_offset);
load_offset -= sizeof(long);
emit_insn(ctx, ldd, LOONGARCH_GPR_S4, LOONGARCH_GPR_SP, load_offset);
load_offset -= sizeof(long);
emit_insn(ctx, ldd, LOONGARCH_GPR_S5, LOONGARCH_GPR_SP, load_offset);
emit_insn(ctx, addid, LOONGARCH_GPR_SP, LOONGARCH_GPR_SP, stack_adjust);
if (!is_tail_call) {
/* Set return value */
move_reg(ctx, LOONGARCH_GPR_A0, regmap[BPF_REG_0]);
/* Return to the caller */
emit_insn(ctx, jirl, LOONGARCH_GPR_RA, LOONGARCH_GPR_ZERO, 0);
} else {
/*
* Call the next bpf prog and skip the first instruction
* of TCC initialization.
*/
emit_insn(ctx, jirl, LOONGARCH_GPR_T3, LOONGARCH_GPR_ZERO, 1);
}
}
static void build_epilogue(struct jit_ctx *ctx)
{
__build_epilogue(ctx, false);
}
bool bpf_jit_supports_kfunc_call(void)
{
return true;
}
/* initialized on the first pass of build_body() */
static int out_offset = -1;
static int emit_bpf_tail_call(struct jit_ctx *ctx)
{
int off;
u8 tcc = tail_call_reg(ctx);
u8 a1 = LOONGARCH_GPR_A1;
u8 a2 = LOONGARCH_GPR_A2;
u8 t1 = LOONGARCH_GPR_T1;
u8 t2 = LOONGARCH_GPR_T2;
u8 t3 = LOONGARCH_GPR_T3;
const int idx0 = ctx->idx;
#define cur_offset (ctx->idx - idx0)
#define jmp_offset (out_offset - (cur_offset))
/*
* a0: &ctx
* a1: &array
* a2: index
*
* if (index >= array->map.max_entries)
* goto out;
*/
off = offsetof(struct bpf_array, map.max_entries);
emit_insn(ctx, ldwu, t1, a1, off);
/* bgeu $a2, $t1, jmp_offset */
if (emit_tailcall_jmp(ctx, BPF_JGE, a2, t1, jmp_offset) < 0)
goto toofar;
/*
* if (--TCC < 0)
* goto out;
*/
emit_insn(ctx, addid, REG_TCC, tcc, -1);
if (emit_tailcall_jmp(ctx, BPF_JSLT, REG_TCC, LOONGARCH_GPR_ZERO, jmp_offset) < 0)
goto toofar;
/*
* prog = array->ptrs[index];
* if (!prog)
* goto out;
*/
emit_insn(ctx, alsld, t2, a2, a1, 2);
off = offsetof(struct bpf_array, ptrs);
emit_insn(ctx, ldd, t2, t2, off);
/* beq $t2, $zero, jmp_offset */
if (emit_tailcall_jmp(ctx, BPF_JEQ, t2, LOONGARCH_GPR_ZERO, jmp_offset) < 0)
goto toofar;
/* goto *(prog->bpf_func + 4); */
off = offsetof(struct bpf_prog, bpf_func);
emit_insn(ctx, ldd, t3, t2, off);
__build_epilogue(ctx, true);
/* out: */
if (out_offset == -1)
out_offset = cur_offset;
if (cur_offset != out_offset) {
pr_err_once("tail_call out_offset = %d, expected %d!\n",
cur_offset, out_offset);
return -1;
}
return 0;
toofar:
pr_info_once("tail_call: jump too far\n");
return -1;
#undef cur_offset
#undef jmp_offset
}
static void emit_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx)
{
const u8 t1 = LOONGARCH_GPR_T1;
const u8 t2 = LOONGARCH_GPR_T2;
const u8 t3 = LOONGARCH_GPR_T3;
const u8 r0 = regmap[BPF_REG_0];
const u8 src = regmap[insn->src_reg];
const u8 dst = regmap[insn->dst_reg];
const s16 off = insn->off;
const s32 imm = insn->imm;
const bool isdw = BPF_SIZE(insn->code) == BPF_DW;
move_imm(ctx, t1, off, false);
emit_insn(ctx, addd, t1, dst, t1);
move_reg(ctx, t3, src);
switch (imm) {
/* lock *(size *)(dst + off) <op>= src */
case BPF_ADD:
if (isdw)
emit_insn(ctx, amaddd, t2, t1, src);
else
emit_insn(ctx, amaddw, t2, t1, src);
break;
case BPF_AND:
if (isdw)
emit_insn(ctx, amandd, t2, t1, src);
else
emit_insn(ctx, amandw, t2, t1, src);
break;
case BPF_OR:
if (isdw)
emit_insn(ctx, amord, t2, t1, src);
else
emit_insn(ctx, amorw, t2, t1, src);
break;
case BPF_XOR:
if (isdw)
emit_insn(ctx, amxord, t2, t1, src);
else
emit_insn(ctx, amxorw, t2, t1, src);
break;
/* src = atomic_fetch_<op>(dst + off, src) */
case BPF_ADD | BPF_FETCH:
if (isdw) {
emit_insn(ctx, amaddd, src, t1, t3);
} else {
emit_insn(ctx, amaddw, src, t1, t3);
emit_zext_32(ctx, src, true);
}
break;
case BPF_AND | BPF_FETCH:
if (isdw) {
emit_insn(ctx, amandd, src, t1, t3);
} else {
emit_insn(ctx, amandw, src, t1, t3);
emit_zext_32(ctx, src, true);
}
break;
case BPF_OR | BPF_FETCH:
if (isdw) {
emit_insn(ctx, amord, src, t1, t3);
} else {
emit_insn(ctx, amorw, src, t1, t3);
emit_zext_32(ctx, src, true);
}
break;
case BPF_XOR | BPF_FETCH:
if (isdw) {
emit_insn(ctx, amxord, src, t1, t3);
} else {
emit_insn(ctx, amxorw, src, t1, t3);
emit_zext_32(ctx, src, true);
}
break;
/* src = atomic_xchg(dst + off, src); */
case BPF_XCHG:
if (isdw) {
emit_insn(ctx, amswapd, src, t1, t3);
} else {
emit_insn(ctx, amswapw, src, t1, t3);
emit_zext_32(ctx, src, true);
}
break;
/* r0 = atomic_cmpxchg(dst + off, r0, src); */
case BPF_CMPXCHG:
move_reg(ctx, t2, r0);
if (isdw) {
emit_insn(ctx, lld, r0, t1, 0);
emit_insn(ctx, bne, t2, r0, 4);
move_reg(ctx, t3, src);
emit_insn(ctx, scd, t3, t1, 0);
emit_insn(ctx, beq, t3, LOONGARCH_GPR_ZERO, -4);
} else {
emit_insn(ctx, llw, r0, t1, 0);
emit_zext_32(ctx, t2, true);
emit_zext_32(ctx, r0, true);
emit_insn(ctx, bne, t2, r0, 4);
move_reg(ctx, t3, src);
emit_insn(ctx, scw, t3, t1, 0);
emit_insn(ctx, beq, t3, LOONGARCH_GPR_ZERO, -6);
emit_zext_32(ctx, r0, true);
}
break;
}
}
static bool is_signed_bpf_cond(u8 cond)
{
return cond == BPF_JSGT || cond == BPF_JSLT ||
cond == BPF_JSGE || cond == BPF_JSLE;
}
#define BPF_FIXUP_REG_MASK GENMASK(31, 27)
#define BPF_FIXUP_OFFSET_MASK GENMASK(26, 0)
bool ex_handler_bpf(const struct exception_table_entry *ex,
struct pt_regs *regs)
{
int dst_reg = FIELD_GET(BPF_FIXUP_REG_MASK, ex->fixup);
off_t offset = FIELD_GET(BPF_FIXUP_OFFSET_MASK, ex->fixup);
regs->regs[dst_reg] = 0;
regs->csr_era = (unsigned long)&ex->fixup - offset;
return true;
}
/* For accesses to BTF pointers, add an entry to the exception table */
static int add_exception_handler(const struct bpf_insn *insn,
struct jit_ctx *ctx,
int dst_reg)
{
unsigned long pc;
off_t offset;
struct exception_table_entry *ex;
if (!ctx->image || !ctx->prog->aux->extable || BPF_MODE(insn->code) != BPF_PROBE_MEM)
return 0;
if (WARN_ON_ONCE(ctx->num_exentries >= ctx->prog->aux->num_exentries))
return -EINVAL;
ex = &ctx->prog->aux->extable[ctx->num_exentries];
pc = (unsigned long)&ctx->image[ctx->idx - 1];
offset = pc - (long)&ex->insn;
if (WARN_ON_ONCE(offset >= 0 || offset < INT_MIN))
return -ERANGE;
ex->insn = offset;
/*
* Since the extable follows the program, the fixup offset is always
* negative and limited to BPF_JIT_REGION_SIZE. Store a positive value
* to keep things simple, and put the destination register in the upper
* bits. We don't need to worry about buildtime or runtime sort
* modifying the upper bits because the table is already sorted, and
* isn't part of the main exception table.
*/
offset = (long)&ex->fixup - (pc + LOONGARCH_INSN_SIZE);
if (!FIELD_FIT(BPF_FIXUP_OFFSET_MASK, offset))
return -ERANGE;
ex->type = EX_TYPE_BPF;
ex->fixup = FIELD_PREP(BPF_FIXUP_OFFSET_MASK, offset) | FIELD_PREP(BPF_FIXUP_REG_MASK, dst_reg);
ctx->num_exentries++;
return 0;
}
static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool extra_pass)
{
u8 tm = -1;
u64 func_addr;
bool func_addr_fixed;
int i = insn - ctx->prog->insnsi;
int ret, jmp_offset;
const u8 code = insn->code;
const u8 cond = BPF_OP(code);
const u8 t1 = LOONGARCH_GPR_T1;
const u8 t2 = LOONGARCH_GPR_T2;
const u8 src = regmap[insn->src_reg];
const u8 dst = regmap[insn->dst_reg];
const s16 off = insn->off;
const s32 imm = insn->imm;
const u64 imm64 = (u64)(insn + 1)->imm << 32 | (u32)insn->imm;
const bool is32 = BPF_CLASS(insn->code) == BPF_ALU || BPF_CLASS(insn->code) == BPF_JMP32;
switch (code) {
/* dst = src */
case BPF_ALU | BPF_MOV | BPF_X:
case BPF_ALU64 | BPF_MOV | BPF_X:
move_reg(ctx, dst, src);
emit_zext_32(ctx, dst, is32);
break;
/* dst = imm */
case BPF_ALU | BPF_MOV | BPF_K:
case BPF_ALU64 | BPF_MOV | BPF_K:
move_imm(ctx, dst, imm, is32);
break;
/* dst = dst + src */
case BPF_ALU | BPF_ADD | BPF_X:
case BPF_ALU64 | BPF_ADD | BPF_X:
emit_insn(ctx, addd, dst, dst, src);
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst + imm */
case BPF_ALU | BPF_ADD | BPF_K:
case BPF_ALU64 | BPF_ADD | BPF_K:
if (is_signed_imm12(imm)) {
emit_insn(ctx, addid, dst, dst, imm);
} else {
move_imm(ctx, t1, imm, is32);
emit_insn(ctx, addd, dst, dst, t1);
}
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst - src */
case BPF_ALU | BPF_SUB | BPF_X:
case BPF_ALU64 | BPF_SUB | BPF_X:
emit_insn(ctx, subd, dst, dst, src);
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst - imm */
case BPF_ALU | BPF_SUB | BPF_K:
case BPF_ALU64 | BPF_SUB | BPF_K:
if (is_signed_imm12(-imm)) {
emit_insn(ctx, addid, dst, dst, -imm);
} else {
move_imm(ctx, t1, imm, is32);
emit_insn(ctx, subd, dst, dst, t1);
}
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst * src */
case BPF_ALU | BPF_MUL | BPF_X:
case BPF_ALU64 | BPF_MUL | BPF_X:
emit_insn(ctx, muld, dst, dst, src);
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst * imm */
case BPF_ALU | BPF_MUL | BPF_K:
case BPF_ALU64 | BPF_MUL | BPF_K:
move_imm(ctx, t1, imm, is32);
emit_insn(ctx, muld, dst, dst, t1);
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst / src */
case BPF_ALU | BPF_DIV | BPF_X:
case BPF_ALU64 | BPF_DIV | BPF_X:
emit_zext_32(ctx, dst, is32);
move_reg(ctx, t1, src);
emit_zext_32(ctx, t1, is32);
emit_insn(ctx, divdu, dst, dst, t1);
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst / imm */
case BPF_ALU | BPF_DIV | BPF_K:
case BPF_ALU64 | BPF_DIV | BPF_K:
move_imm(ctx, t1, imm, is32);
emit_zext_32(ctx, dst, is32);
emit_insn(ctx, divdu, dst, dst, t1);
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst % src */
case BPF_ALU | BPF_MOD | BPF_X:
case BPF_ALU64 | BPF_MOD | BPF_X:
emit_zext_32(ctx, dst, is32);
move_reg(ctx, t1, src);
emit_zext_32(ctx, t1, is32);
emit_insn(ctx, moddu, dst, dst, t1);
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst % imm */
case BPF_ALU | BPF_MOD | BPF_K:
case BPF_ALU64 | BPF_MOD | BPF_K:
move_imm(ctx, t1, imm, is32);
emit_zext_32(ctx, dst, is32);
emit_insn(ctx, moddu, dst, dst, t1);
emit_zext_32(ctx, dst, is32);
break;
/* dst = -dst */
case BPF_ALU | BPF_NEG:
case BPF_ALU64 | BPF_NEG:
move_imm(ctx, t1, imm, is32);
emit_insn(ctx, subd, dst, LOONGARCH_GPR_ZERO, dst);
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst & src */
case BPF_ALU | BPF_AND | BPF_X:
case BPF_ALU64 | BPF_AND | BPF_X:
emit_insn(ctx, and, dst, dst, src);
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst & imm */
case BPF_ALU | BPF_AND | BPF_K:
case BPF_ALU64 | BPF_AND | BPF_K:
if (is_unsigned_imm12(imm)) {
emit_insn(ctx, andi, dst, dst, imm);
} else {
move_imm(ctx, t1, imm, is32);
emit_insn(ctx, and, dst, dst, t1);
}
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst | src */
case BPF_ALU | BPF_OR | BPF_X:
case BPF_ALU64 | BPF_OR | BPF_X:
emit_insn(ctx, or, dst, dst, src);
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst | imm */
case BPF_ALU | BPF_OR | BPF_K:
case BPF_ALU64 | BPF_OR | BPF_K:
if (is_unsigned_imm12(imm)) {
emit_insn(ctx, ori, dst, dst, imm);
} else {
move_imm(ctx, t1, imm, is32);
emit_insn(ctx, or, dst, dst, t1);
}
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst ^ src */
case BPF_ALU | BPF_XOR | BPF_X:
case BPF_ALU64 | BPF_XOR | BPF_X:
emit_insn(ctx, xor, dst, dst, src);
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst ^ imm */
case BPF_ALU | BPF_XOR | BPF_K:
case BPF_ALU64 | BPF_XOR | BPF_K:
if (is_unsigned_imm12(imm)) {
emit_insn(ctx, xori, dst, dst, imm);
} else {
move_imm(ctx, t1, imm, is32);
emit_insn(ctx, xor, dst, dst, t1);
}
emit_zext_32(ctx, dst, is32);
break;
/* dst = dst << src (logical) */
case BPF_ALU | BPF_LSH | BPF_X:
emit_insn(ctx, sllw, dst, dst, src);
emit_zext_32(ctx, dst, is32);
break;
case BPF_ALU64 | BPF_LSH | BPF_X:
emit_insn(ctx, slld, dst, dst, src);
break;
/* dst = dst << imm (logical) */
case BPF_ALU | BPF_LSH | BPF_K:
emit_insn(ctx, slliw, dst, dst, imm);
emit_zext_32(ctx, dst, is32);
break;
case BPF_ALU64 | BPF_LSH | BPF_K:
emit_insn(ctx, sllid, dst, dst, imm);
break;
/* dst = dst >> src (logical) */
case BPF_ALU | BPF_RSH | BPF_X:
emit_insn(ctx, srlw, dst, dst, src);
emit_zext_32(ctx, dst, is32);
break;
case BPF_ALU64 | BPF_RSH | BPF_X:
emit_insn(ctx, srld, dst, dst, src);
break;
/* dst = dst >> imm (logical) */
case BPF_ALU | BPF_RSH | BPF_K:
emit_insn(ctx, srliw, dst, dst, imm);
emit_zext_32(ctx, dst, is32);
break;
case BPF_ALU64 | BPF_RSH | BPF_K:
emit_insn(ctx, srlid, dst, dst, imm);
break;
/* dst = dst >> src (arithmetic) */
case BPF_ALU | BPF_ARSH | BPF_X:
emit_insn(ctx, sraw, dst, dst, src);
emit_zext_32(ctx, dst, is32);
break;
case BPF_ALU64 | BPF_ARSH | BPF_X:
emit_insn(ctx, srad, dst, dst, src);
break;
/* dst = dst >> imm (arithmetic) */
case BPF_ALU | BPF_ARSH | BPF_K:
emit_insn(ctx, sraiw, dst, dst, imm);
emit_zext_32(ctx, dst, is32);
break;
case BPF_ALU64 | BPF_ARSH | BPF_K:
emit_insn(ctx, sraid, dst, dst, imm);
break;
/* dst = BSWAP##imm(dst) */
case BPF_ALU | BPF_END | BPF_FROM_LE:
switch (imm) {
case 16:
/* zero-extend 16 bits into 64 bits */
emit_insn(ctx, bstrpickd, dst, dst, 15, 0);
break;
case 32:
/* zero-extend 32 bits into 64 bits */
emit_zext_32(ctx, dst, is32);
break;
case 64:
/* do nothing */
break;
}
break;
case BPF_ALU | BPF_END | BPF_FROM_BE:
switch (imm) {
case 16:
emit_insn(ctx, revb2h, dst, dst);
/* zero-extend 16 bits into 64 bits */
emit_insn(ctx, bstrpickd, dst, dst, 15, 0);
break;
case 32:
emit_insn(ctx, revb2w, dst, dst);
/* zero-extend 32 bits into 64 bits */
emit_zext_32(ctx, dst, is32);
break;
case 64:
emit_insn(ctx, revbd, dst, dst);
break;
}
break;
/* PC += off if dst cond src */
case BPF_JMP | BPF_JEQ | BPF_X:
case BPF_JMP | BPF_JNE | BPF_X:
case BPF_JMP | BPF_JGT | BPF_X:
case BPF_JMP | BPF_JGE | BPF_X:
case BPF_JMP | BPF_JLT | BPF_X:
case BPF_JMP | BPF_JLE | BPF_X:
case BPF_JMP | BPF_JSGT | BPF_X:
case BPF_JMP | BPF_JSGE | BPF_X:
case BPF_JMP | BPF_JSLT | BPF_X:
case BPF_JMP | BPF_JSLE | BPF_X:
case BPF_JMP32 | BPF_JEQ | BPF_X:
case BPF_JMP32 | BPF_JNE | BPF_X:
case BPF_JMP32 | BPF_JGT | BPF_X:
case BPF_JMP32 | BPF_JGE | BPF_X:
case BPF_JMP32 | BPF_JLT | BPF_X:
case BPF_JMP32 | BPF_JLE | BPF_X:
case BPF_JMP32 | BPF_JSGT | BPF_X:
case BPF_JMP32 | BPF_JSGE | BPF_X:
case BPF_JMP32 | BPF_JSLT | BPF_X:
case BPF_JMP32 | BPF_JSLE | BPF_X:
jmp_offset = bpf2la_offset(i, off, ctx);
move_reg(ctx, t1, dst);
move_reg(ctx, t2, src);
if (is_signed_bpf_cond(BPF_OP(code))) {
emit_sext_32(ctx, t1, is32);
emit_sext_32(ctx, t2, is32);
} else {
emit_zext_32(ctx, t1, is32);
emit_zext_32(ctx, t2, is32);
}
if (emit_cond_jmp(ctx, cond, t1, t2, jmp_offset) < 0)
goto toofar;
break;
/* PC += off if dst cond imm */
case BPF_JMP | BPF_JEQ | BPF_K:
case BPF_JMP | BPF_JNE | BPF_K:
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:
case BPF_JMP | BPF_JSGT | BPF_K:
case BPF_JMP | BPF_JSGE | BPF_K:
case BPF_JMP | BPF_JSLT | BPF_K:
case BPF_JMP | BPF_JSLE | BPF_K:
case BPF_JMP32 | BPF_JEQ | BPF_K:
case BPF_JMP32 | BPF_JNE | BPF_K:
case BPF_JMP32 | BPF_JGT | BPF_K:
case BPF_JMP32 | BPF_JGE | BPF_K:
case BPF_JMP32 | BPF_JLT | BPF_K:
case BPF_JMP32 | BPF_JLE | BPF_K:
case BPF_JMP32 | BPF_JSGT | BPF_K:
case BPF_JMP32 | BPF_JSGE | BPF_K:
case BPF_JMP32 | BPF_JSLT | BPF_K:
case BPF_JMP32 | BPF_JSLE | BPF_K:
jmp_offset = bpf2la_offset(i, off, ctx);
if (imm) {
move_imm(ctx, t1, imm, false);
tm = t1;
} else {
/* If imm is 0, simply use zero register. */
tm = LOONGARCH_GPR_ZERO;
}
move_reg(ctx, t2, dst);
if (is_signed_bpf_cond(BPF_OP(code))) {
emit_sext_32(ctx, tm, is32);
emit_sext_32(ctx, t2, is32);
} else {
emit_zext_32(ctx, tm, is32);
emit_zext_32(ctx, t2, is32);
}
if (emit_cond_jmp(ctx, cond, t2, tm, jmp_offset) < 0)
goto toofar;
break;
/* PC += off if dst & src */
case BPF_JMP | BPF_JSET | BPF_X:
case BPF_JMP32 | BPF_JSET | BPF_X:
jmp_offset = bpf2la_offset(i, off, ctx);
emit_insn(ctx, and, t1, dst, src);
emit_zext_32(ctx, t1, is32);
if (emit_cond_jmp(ctx, cond, t1, LOONGARCH_GPR_ZERO, jmp_offset) < 0)
goto toofar;
break;
/* PC += off if dst & imm */
case BPF_JMP | BPF_JSET | BPF_K:
case BPF_JMP32 | BPF_JSET | BPF_K:
jmp_offset = bpf2la_offset(i, off, ctx);
move_imm(ctx, t1, imm, is32);
emit_insn(ctx, and, t1, dst, t1);
emit_zext_32(ctx, t1, is32);
if (emit_cond_jmp(ctx, cond, t1, LOONGARCH_GPR_ZERO, jmp_offset) < 0)
goto toofar;
break;
/* PC += off */
case BPF_JMP | BPF_JA:
jmp_offset = bpf2la_offset(i, off, ctx);
if (emit_uncond_jmp(ctx, jmp_offset) < 0)
goto toofar;
break;
/* function call */
case BPF_JMP | BPF_CALL:
mark_call(ctx);
ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass,
&func_addr, &func_addr_fixed);
if (ret < 0)
return ret;
move_addr(ctx, t1, func_addr);
emit_insn(ctx, jirl, t1, LOONGARCH_GPR_RA, 0);
move_reg(ctx, regmap[BPF_REG_0], LOONGARCH_GPR_A0);
break;
/* tail call */
case BPF_JMP | BPF_TAIL_CALL:
mark_tail_call(ctx);
if (emit_bpf_tail_call(ctx) < 0)
return -EINVAL;
break;
/* function return */
case BPF_JMP | BPF_EXIT:
emit_sext_32(ctx, regmap[BPF_REG_0], true);
if (i == ctx->prog->len - 1)
break;
jmp_offset = epilogue_offset(ctx);
if (emit_uncond_jmp(ctx, jmp_offset) < 0)
goto toofar;
break;
/* dst = imm64 */
case BPF_LD | BPF_IMM | BPF_DW:
move_imm(ctx, dst, imm64, is32);
return 1;
/* dst = *(size *)(src + off) */
case BPF_LDX | BPF_MEM | BPF_B:
case BPF_LDX | BPF_MEM | BPF_H:
case BPF_LDX | BPF_MEM | BPF_W:
case BPF_LDX | BPF_MEM | BPF_DW:
case BPF_LDX | BPF_PROBE_MEM | BPF_DW:
case BPF_LDX | BPF_PROBE_MEM | BPF_W:
case BPF_LDX | BPF_PROBE_MEM | BPF_H:
case BPF_LDX | BPF_PROBE_MEM | BPF_B:
switch (BPF_SIZE(code)) {
case BPF_B:
if (is_signed_imm12(off)) {
emit_insn(ctx, ldbu, dst, src, off);
} else {
move_imm(ctx, t1, off, is32);
emit_insn(ctx, ldxbu, dst, src, t1);
}
break;
case BPF_H:
if (is_signed_imm12(off)) {
emit_insn(ctx, ldhu, dst, src, off);
} else {
move_imm(ctx, t1, off, is32);
emit_insn(ctx, ldxhu, dst, src, t1);
}
break;
case BPF_W:
if (is_signed_imm12(off)) {
emit_insn(ctx, ldwu, dst, src, off);
} else if (is_signed_imm14(off)) {
emit_insn(ctx, ldptrw, dst, src, off);
} else {
move_imm(ctx, t1, off, is32);
emit_insn(ctx, ldxwu, dst, src, t1);
}
break;
case BPF_DW:
if (is_signed_imm12(off)) {
emit_insn(ctx, ldd, dst, src, off);
} else if (is_signed_imm14(off)) {
emit_insn(ctx, ldptrd, dst, src, off);
} else {
move_imm(ctx, t1, off, is32);
emit_insn(ctx, ldxd, dst, src, t1);
}
break;
}
ret = add_exception_handler(insn, ctx, dst);
if (ret)
return ret;
break;
/* *(size *)(dst + off) = imm */
case BPF_ST | BPF_MEM | BPF_B:
case BPF_ST | BPF_MEM | BPF_H:
case BPF_ST | BPF_MEM | BPF_W:
case BPF_ST | BPF_MEM | BPF_DW:
switch (BPF_SIZE(code)) {
case BPF_B:
move_imm(ctx, t1, imm, is32);
if (is_signed_imm12(off)) {
emit_insn(ctx, stb, t1, dst, off);
} else {
move_imm(ctx, t2, off, is32);
emit_insn(ctx, stxb, t1, dst, t2);
}
break;
case BPF_H:
move_imm(ctx, t1, imm, is32);
if (is_signed_imm12(off)) {
emit_insn(ctx, sth, t1, dst, off);
} else {
move_imm(ctx, t2, off, is32);
emit_insn(ctx, stxh, t1, dst, t2);
}
break;
case BPF_W:
move_imm(ctx, t1, imm, is32);
if (is_signed_imm12(off)) {
emit_insn(ctx, stw, t1, dst, off);
} else if (is_signed_imm14(off)) {
emit_insn(ctx, stptrw, t1, dst, off);
} else {
move_imm(ctx, t2, off, is32);
emit_insn(ctx, stxw, t1, dst, t2);
}
break;
case BPF_DW:
move_imm(ctx, t1, imm, is32);
if (is_signed_imm12(off)) {
emit_insn(ctx, std, t1, dst, off);
} else if (is_signed_imm14(off)) {
emit_insn(ctx, stptrd, t1, dst, off);
} else {
move_imm(ctx, t2, off, is32);
emit_insn(ctx, stxd, t1, dst, t2);
}
break;
}
break;
/* *(size *)(dst + off) = src */
case BPF_STX | BPF_MEM | BPF_B:
case BPF_STX | BPF_MEM | BPF_H:
case BPF_STX | BPF_MEM | BPF_W:
case BPF_STX | BPF_MEM | BPF_DW:
switch (BPF_SIZE(code)) {
case BPF_B:
if (is_signed_imm12(off)) {
emit_insn(ctx, stb, src, dst, off);
} else {
move_imm(ctx, t1, off, is32);
emit_insn(ctx, stxb, src, dst, t1);
}
break;
case BPF_H:
if (is_signed_imm12(off)) {
emit_insn(ctx, sth, src, dst, off);
} else {
move_imm(ctx, t1, off, is32);
emit_insn(ctx, stxh, src, dst, t1);
}
break;
case BPF_W:
if (is_signed_imm12(off)) {
emit_insn(ctx, stw, src, dst, off);
} else if (is_signed_imm14(off)) {
emit_insn(ctx, stptrw, src, dst, off);
} else {
move_imm(ctx, t1, off, is32);
emit_insn(ctx, stxw, src, dst, t1);
}
break;
case BPF_DW:
if (is_signed_imm12(off)) {
emit_insn(ctx, std, src, dst, off);
} else if (is_signed_imm14(off)) {
emit_insn(ctx, stptrd, src, dst, off);
} else {
move_imm(ctx, t1, off, is32);
emit_insn(ctx, stxd, src, dst, t1);
}
break;
}
break;
case BPF_STX | BPF_ATOMIC | BPF_W:
case BPF_STX | BPF_ATOMIC | BPF_DW:
emit_atomic(insn, ctx);
break;
/* Speculation barrier */
case BPF_ST | BPF_NOSPEC:
break;
default:
pr_err("bpf_jit: unknown opcode %02x\n", code);
return -EINVAL;
}
return 0;
toofar:
pr_info_once("bpf_jit: opcode %02x, jump too far\n", code);
return -E2BIG;
}
static int build_body(struct jit_ctx *ctx, bool extra_pass)
{
int i;
const struct bpf_prog *prog = ctx->prog;
for (i = 0; i < prog->len; i++) {
const struct bpf_insn *insn = &prog->insnsi[i];
int ret;
if (ctx->image == NULL)
ctx->offset[i] = ctx->idx;
ret = build_insn(insn, ctx, extra_pass);
if (ret > 0) {
i++;
if (ctx->image == NULL)
ctx->offset[i] = ctx->idx;
continue;
}
if (ret)
return ret;
}
if (ctx->image == NULL)
ctx->offset[i] = ctx->idx;
return 0;
}
/* Fill space with break instructions */
static void jit_fill_hole(void *area, unsigned int size)
{
u32 *ptr;
/* We are guaranteed to have aligned memory */
for (ptr = area; size >= sizeof(u32); size -= sizeof(u32))
*ptr++ = INSN_BREAK;
}
static int validate_code(struct jit_ctx *ctx)
{
int i;
union loongarch_instruction insn;
for (i = 0; i < ctx->idx; i++) {
insn = ctx->image[i];
/* Check INSN_BREAK */
if (insn.word == INSN_BREAK)
return -1;
}
if (WARN_ON_ONCE(ctx->num_exentries != ctx->prog->aux->num_exentries))
return -1;
return 0;
}
struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
{
bool tmp_blinded = false, extra_pass = false;
u8 *image_ptr;
int image_size, prog_size, extable_size;
struct jit_ctx ctx;
struct jit_data *jit_data;
struct bpf_binary_header *header;
struct bpf_prog *tmp, *orig_prog = prog;
/*
* If BPF JIT was not enabled then we must fall back to
* the interpreter.
*/
if (!prog->jit_requested)
return orig_prog;
tmp = bpf_jit_blind_constants(prog);
/*
* If blinding was requested and we failed during blinding,
* we must fall back to the interpreter. Otherwise, we save
* the new JITed code.
*/
if (IS_ERR(tmp))
return orig_prog;
if (tmp != prog) {
tmp_blinded = true;
prog = tmp;
}
jit_data = prog->aux->jit_data;
if (!jit_data) {
jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
if (!jit_data) {
prog = orig_prog;
goto out;
}
prog->aux->jit_data = jit_data;
}
if (jit_data->ctx.offset) {
ctx = jit_data->ctx;
image_ptr = jit_data->image;
header = jit_data->header;
extra_pass = true;
prog_size = sizeof(u32) * ctx.idx;
goto skip_init_ctx;
}
memset(&ctx, 0, sizeof(ctx));
ctx.prog = prog;
ctx.offset = kvcalloc(prog->len + 1, sizeof(u32), GFP_KERNEL);
if (ctx.offset == NULL) {
prog = orig_prog;
goto out_offset;
}
/* 1. Initial fake pass to compute ctx->idx and set ctx->flags */
build_prologue(&ctx);
if (build_body(&ctx, extra_pass)) {
prog = orig_prog;
goto out_offset;
}
ctx.epilogue_offset = ctx.idx;
build_epilogue(&ctx);
extable_size = prog->aux->num_exentries * sizeof(struct exception_table_entry);
/* Now we know the actual image size.
* As each LoongArch instruction is of length 32bit,
* we are translating number of JITed intructions into
* the size required to store these JITed code.
*/
prog_size = sizeof(u32) * ctx.idx;
image_size = prog_size + extable_size;
/* Now we know the size of the structure to make */
header = bpf_jit_binary_alloc(image_size, &image_ptr,
sizeof(u32), jit_fill_hole);
if (header == NULL) {
prog = orig_prog;
goto out_offset;
}
/* 2. Now, the actual pass to generate final JIT code */
ctx.image = (union loongarch_instruction *)image_ptr;
if (extable_size)
prog->aux->extable = (void *)image_ptr + prog_size;
skip_init_ctx:
ctx.idx = 0;
ctx.num_exentries = 0;
build_prologue(&ctx);
if (build_body(&ctx, extra_pass)) {
bpf_jit_binary_free(header);
prog = orig_prog;
goto out_offset;
}
build_epilogue(&ctx);
/* 3. Extra pass to validate JITed code */
if (validate_code(&ctx)) {
bpf_jit_binary_free(header);
prog = orig_prog;
goto out_offset;
}
/* And we're done */
if (bpf_jit_enable > 1)
bpf_jit_dump(prog->len, prog_size, 2, ctx.image);
/* Update the icache */
flush_icache_range((unsigned long)header, (unsigned long)(ctx.image + ctx.idx));
if (!prog->is_func || extra_pass) {
if (extra_pass && ctx.idx != jit_data->ctx.idx) {
pr_err_once("multi-func JIT bug %d != %d\n",
ctx.idx, jit_data->ctx.idx);
bpf_jit_binary_free(header);
prog->bpf_func = NULL;
prog->jited = 0;
prog->jited_len = 0;
goto out_offset;
}
bpf_jit_binary_lock_ro(header);
} else {
jit_data->ctx = ctx;
jit_data->image = image_ptr;
jit_data->header = header;
}
prog->jited = 1;
prog->jited_len = prog_size;
prog->bpf_func = (void *)ctx.image;
if (!prog->is_func || extra_pass) {
int i;
/* offset[prog->len] is the size of program */
for (i = 0; i <= prog->len; i++)
ctx.offset[i] *= LOONGARCH_INSN_SIZE;
bpf_prog_fill_jited_linfo(prog, ctx.offset + 1);
out_offset:
kvfree(ctx.offset);
kfree(jit_data);
prog->aux->jit_data = NULL;
}
out:
if (tmp_blinded)
bpf_jit_prog_release_other(prog, prog == orig_prog ? tmp : orig_prog);
out_offset = -1;
return prog;
}
6.5.5
2023-10-24 12:59:35 +02:00
/* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */
bool bpf_jit_supports_subprog_tailcalls(void)
{
return true;
}