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linux/arch/mips/net/bpf_jit_comp64.c
Jiaxun Yang 7364d60c26 bpf, mips: Implement R4000 workarounds for JIT 
For R4000 erratas around multiplication and division instructions,
as our use of those instructions are always followed by mflo/mfhi
instructions, the only issue we need care is

"MIPS R4000PC/SC Errata, Processor Revision 2.2 and 3.0" Errata 28:
"A double-word or a variable shift may give an incorrect result if
executed while an integer multiplication is in progress."

We just emit a mfhi $0 to ensure the operation is completed after
every multiplication instruction according to workaround suggestion
in the document.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Link: https://lore.kernel.org/bpf/20230228113305.83751-3-jiaxun.yang@flygoat.com
2023-02-28 14:52:55 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Just-In-Time compiler for eBPF bytecode on MIPS.
* Implementation of JIT functions for 64-bit CPUs.
*
* Copyright (c) 2021 Anyfi Networks AB.
* Author: Johan Almbladh <johan.almbladh@gmail.com>
*
* Based on code and ideas from
* Copyright (c) 2017 Cavium, Inc.
* Copyright (c) 2017 Shubham Bansal <illusionist.neo@gmail.com>
* Copyright (c) 2011 Mircea Gherzan <mgherzan@gmail.com>
*/
#include <linux/errno.h>
#include <linux/filter.h>
#include <linux/bpf.h>
#include <asm/cpu-features.h>
#include <asm/isa-rev.h>
#include <asm/uasm.h>
#include "bpf_jit_comp.h"
/* MIPS t0-t3 are not available in the n64 ABI */
#undef MIPS_R_T0
#undef MIPS_R_T1
#undef MIPS_R_T2
#undef MIPS_R_T3
/* Stack is 16-byte aligned in n64 ABI */
#define MIPS_STACK_ALIGNMENT 16
/* Extra 64-bit eBPF registers used by JIT */
#define JIT_REG_TC (MAX_BPF_JIT_REG + 0)
#define JIT_REG_ZX (MAX_BPF_JIT_REG + 1)
/* Number of prologue bytes to skip when doing a tail call */
#define JIT_TCALL_SKIP 4
/* Callee-saved CPU registers that the JIT must preserve */
#define JIT_CALLEE_REGS \
(BIT(MIPS_R_S0) | \
BIT(MIPS_R_S1) | \
BIT(MIPS_R_S2) | \
BIT(MIPS_R_S3) | \
BIT(MIPS_R_S4) | \
BIT(MIPS_R_S5) | \
BIT(MIPS_R_S6) | \
BIT(MIPS_R_S7) | \
BIT(MIPS_R_GP) | \
BIT(MIPS_R_FP) | \
BIT(MIPS_R_RA))
/* Caller-saved CPU registers available for JIT use */
#define JIT_CALLER_REGS \
(BIT(MIPS_R_A5) | \
BIT(MIPS_R_A6) | \
BIT(MIPS_R_A7))
/*
* Mapping of 64-bit eBPF registers to 64-bit native MIPS registers.
* MIPS registers t4 - t7 may be used by the JIT as temporary registers.
* MIPS registers t8 - t9 are reserved for single-register common functions.
*/
static const u8 bpf2mips64[] = {
/* Return value from in-kernel function, and exit value from eBPF */
[BPF_REG_0] = MIPS_R_V0,
/* Arguments from eBPF program to in-kernel function */
[BPF_REG_1] = MIPS_R_A0,
[BPF_REG_2] = MIPS_R_A1,
[BPF_REG_3] = MIPS_R_A2,
[BPF_REG_4] = MIPS_R_A3,
[BPF_REG_5] = MIPS_R_A4,
/* Callee-saved registers that in-kernel function will preserve */
[BPF_REG_6] = MIPS_R_S0,
[BPF_REG_7] = MIPS_R_S1,
[BPF_REG_8] = MIPS_R_S2,
[BPF_REG_9] = MIPS_R_S3,
/* Read-only frame pointer to access the eBPF stack */
[BPF_REG_FP] = MIPS_R_FP,
/* Temporary register for blinding constants */
[BPF_REG_AX] = MIPS_R_AT,
/* Tail call count register, caller-saved */
[JIT_REG_TC] = MIPS_R_A5,
/* Constant for register zero-extension */
[JIT_REG_ZX] = MIPS_R_V1,
};
/*
* MIPS 32-bit operations on 64-bit registers generate a sign-extended
* result. However, the eBPF ISA mandates zero-extension, so we rely on the
* verifier to add that for us (emit_zext_ver). In addition, ALU arithmetic
* operations, right shift and byte swap require properly sign-extended
* operands or the result is unpredictable. We emit explicit sign-extensions
* in those cases.
*/
/* Sign extension */
static void emit_sext(struct jit_context *ctx, u8 dst, u8 src)
{
emit(ctx, sll, dst, src, 0);
clobber_reg(ctx, dst);
}
/* Zero extension */
static void emit_zext(struct jit_context *ctx, u8 dst)
{
if (cpu_has_mips64r2 || cpu_has_mips64r6) {
emit(ctx, dinsu, dst, MIPS_R_ZERO, 32, 32);
} else {
emit(ctx, and, dst, dst, bpf2mips64[JIT_REG_ZX]);
access_reg(ctx, JIT_REG_ZX); /* We need the ZX register */
}
clobber_reg(ctx, dst);
}
/* Zero extension, if verifier does not do it for us */
static void emit_zext_ver(struct jit_context *ctx, u8 dst)
{
if (!ctx->program->aux->verifier_zext)
emit_zext(ctx, dst);
}
/* dst = imm (64-bit) */
static void emit_mov_i64(struct jit_context *ctx, u8 dst, u64 imm64)
{
if (imm64 >= 0xffffffffffff8000ULL || imm64 < 0x8000ULL) {
emit(ctx, daddiu, dst, MIPS_R_ZERO, (s16)imm64);
} else if (imm64 >= 0xffffffff80000000ULL ||
(imm64 < 0x80000000 && imm64 > 0xffff)) {
emit(ctx, lui, dst, (s16)(imm64 >> 16));
emit(ctx, ori, dst, dst, (u16)imm64 & 0xffff);
} else {
u8 acc = MIPS_R_ZERO;
int shift = 0;
int k;
for (k = 0; k < 4; k++) {
u16 half = imm64 >> (48 - 16 * k);
if (acc == dst)
shift += 16;
if (half) {
if (shift)
emit(ctx, dsll_safe, dst, dst, shift);
emit(ctx, ori, dst, acc, half);
acc = dst;
shift = 0;
}
}
if (shift)
emit(ctx, dsll_safe, dst, dst, shift);
}
clobber_reg(ctx, dst);
}
/* ALU immediate operation (64-bit) */
static void emit_alu_i64(struct jit_context *ctx, u8 dst, s32 imm, u8 op)
{
switch (BPF_OP(op)) {
/* dst = dst | imm */
case BPF_OR:
emit(ctx, ori, dst, dst, (u16)imm);
break;
/* dst = dst ^ imm */
case BPF_XOR:
emit(ctx, xori, dst, dst, (u16)imm);
break;
/* dst = -dst */
case BPF_NEG:
emit(ctx, dsubu, dst, MIPS_R_ZERO, dst);
break;
/* dst = dst << imm */
case BPF_LSH:
emit(ctx, dsll_safe, dst, dst, imm);
break;
/* dst = dst >> imm */
case BPF_RSH:
emit(ctx, dsrl_safe, dst, dst, imm);
break;
/* dst = dst >> imm (arithmetic) */
case BPF_ARSH:
emit(ctx, dsra_safe, dst, dst, imm);
break;
/* dst = dst + imm */
case BPF_ADD:
emit(ctx, daddiu, dst, dst, imm);
break;
/* dst = dst - imm */
case BPF_SUB:
emit(ctx, daddiu, dst, dst, -imm);
break;
default:
/* Width-generic operations */
emit_alu_i(ctx, dst, imm, op);
}
clobber_reg(ctx, dst);
}
/* ALU register operation (64-bit) */
static void emit_alu_r64(struct jit_context *ctx, u8 dst, u8 src, u8 op)
{
switch (BPF_OP(op)) {
/* dst = dst << src */
case BPF_LSH:
emit(ctx, dsllv, dst, dst, src);
break;
/* dst = dst >> src */
case BPF_RSH:
emit(ctx, dsrlv, dst, dst, src);
break;
/* dst = dst >> src (arithmetic) */
case BPF_ARSH:
emit(ctx, dsrav, dst, dst, src);
break;
/* dst = dst + src */
case BPF_ADD:
emit(ctx, daddu, dst, dst, src);
break;
/* dst = dst - src */
case BPF_SUB:
emit(ctx, dsubu, dst, dst, src);
break;
/* dst = dst * src */
case BPF_MUL:
if (cpu_has_mips64r6) {
emit(ctx, dmulu, dst, dst, src);
} else {
emit(ctx, dmultu, dst, src);
emit(ctx, mflo, dst);
/* Ensure multiplication is completed */
if (IS_ENABLED(CONFIG_CPU_R4000_WORKAROUNDS))
emit(ctx, mfhi, MIPS_R_ZERO);
}
break;
/* dst = dst / src */
case BPF_DIV:
if (cpu_has_mips64r6) {
emit(ctx, ddivu_r6, dst, dst, src);
} else {
emit(ctx, ddivu, dst, src);
emit(ctx, mflo, dst);
}
break;
/* dst = dst % src */
case BPF_MOD:
if (cpu_has_mips64r6) {
emit(ctx, dmodu, dst, dst, src);
} else {
emit(ctx, ddivu, dst, src);
emit(ctx, mfhi, dst);
}
break;
default:
/* Width-generic operations */
emit_alu_r(ctx, dst, src, op);
}
clobber_reg(ctx, dst);
}
/* Swap sub words in a register double word */
static void emit_swap_r64(struct jit_context *ctx, u8 dst, u8 mask, u32 bits)
{
u8 tmp = MIPS_R_T9;
emit(ctx, and, tmp, dst, mask); /* tmp = dst & mask */
emit(ctx, dsll, tmp, tmp, bits); /* tmp = tmp << bits */
emit(ctx, dsrl, dst, dst, bits); /* dst = dst >> bits */
emit(ctx, and, dst, dst, mask); /* dst = dst & mask */
emit(ctx, or, dst, dst, tmp); /* dst = dst | tmp */
}
/* Swap bytes and truncate a register double word, word or half word */
static void emit_bswap_r64(struct jit_context *ctx, u8 dst, u32 width)
{
switch (width) {
/* Swap bytes in a double word */
case 64:
if (cpu_has_mips64r2 || cpu_has_mips64r6) {
emit(ctx, dsbh, dst, dst);
emit(ctx, dshd, dst, dst);
} else {
u8 t1 = MIPS_R_T6;
u8 t2 = MIPS_R_T7;
emit(ctx, dsll32, t2, dst, 0); /* t2 = dst << 32 */
emit(ctx, dsrl32, dst, dst, 0); /* dst = dst >> 32 */
emit(ctx, or, dst, dst, t2); /* dst = dst | t2 */
emit(ctx, ori, t2, MIPS_R_ZERO, 0xffff);
emit(ctx, dsll32, t1, t2, 0); /* t1 = t2 << 32 */
emit(ctx, or, t1, t1, t2); /* t1 = t1 | t2 */
emit_swap_r64(ctx, dst, t1, 16);/* dst = swap16(dst) */
emit(ctx, lui, t2, 0xff); /* t2 = 0x00ff0000 */
emit(ctx, ori, t2, t2, 0xff); /* t2 = t2 | 0x00ff */
emit(ctx, dsll32, t1, t2, 0); /* t1 = t2 << 32 */
emit(ctx, or, t1, t1, t2); /* t1 = t1 | t2 */
emit_swap_r64(ctx, dst, t1, 8); /* dst = swap8(dst) */
}
break;
/* Swap bytes in a half word */
/* Swap bytes in a word */
case 32:
case 16:
emit_sext(ctx, dst, dst);
emit_bswap_r(ctx, dst, width);
if (cpu_has_mips64r2 || cpu_has_mips64r6)
emit_zext(ctx, dst);
break;
}
clobber_reg(ctx, dst);
}
/* Truncate a register double word, word or half word */
static void emit_trunc_r64(struct jit_context *ctx, u8 dst, u32 width)
{
switch (width) {
case 64:
break;
/* Zero-extend a word */
case 32:
emit_zext(ctx, dst);
break;
/* Zero-extend a half word */
case 16:
emit(ctx, andi, dst, dst, 0xffff);
break;
}
clobber_reg(ctx, dst);
}
/* Load operation: dst = *(size*)(src + off) */
static void emit_ldx(struct jit_context *ctx, u8 dst, u8 src, s16 off, u8 size)
{
switch (size) {
/* Load a byte */
case BPF_B:
emit(ctx, lbu, dst, off, src);
break;
/* Load a half word */
case BPF_H:
emit(ctx, lhu, dst, off, src);
break;
/* Load a word */
case BPF_W:
emit(ctx, lwu, dst, off, src);
break;
/* Load a double word */
case BPF_DW:
emit(ctx, ld, dst, off, src);
break;
}
clobber_reg(ctx, dst);
}
/* Store operation: *(size *)(dst + off) = src */
static void emit_stx(struct jit_context *ctx, u8 dst, u8 src, s16 off, u8 size)
{
switch (size) {
/* Store a byte */
case BPF_B:
emit(ctx, sb, src, off, dst);
break;
/* Store a half word */
case BPF_H:
emit(ctx, sh, src, off, dst);
break;
/* Store a word */
case BPF_W:
emit(ctx, sw, src, off, dst);
break;
/* Store a double word */
case BPF_DW:
emit(ctx, sd, src, off, dst);
break;
}
}
/* Atomic read-modify-write */
static void emit_atomic_r64(struct jit_context *ctx,
u8 dst, u8 src, s16 off, u8 code)
{
u8 t1 = MIPS_R_T6;
u8 t2 = MIPS_R_T7;
LLSC_sync(ctx);
emit(ctx, lld, t1, off, dst);
switch (code) {
case BPF_ADD:
case BPF_ADD | BPF_FETCH:
emit(ctx, daddu, t2, t1, src);
break;
case BPF_AND:
case BPF_AND | BPF_FETCH:
emit(ctx, and, t2, t1, src);
break;
case BPF_OR:
case BPF_OR | BPF_FETCH:
emit(ctx, or, t2, t1, src);
break;
case BPF_XOR:
case BPF_XOR | BPF_FETCH:
emit(ctx, xor, t2, t1, src);
break;
case BPF_XCHG:
emit(ctx, move, t2, src);
break;
}
emit(ctx, scd, t2, off, dst);
emit(ctx, LLSC_beqz, t2, -16 - LLSC_offset);
emit(ctx, nop); /* Delay slot */
if (code & BPF_FETCH) {
emit(ctx, move, src, t1);
clobber_reg(ctx, src);
}
}
/* Atomic compare-and-exchange */
static void emit_cmpxchg_r64(struct jit_context *ctx, u8 dst, u8 src, s16 off)
{
u8 r0 = bpf2mips64[BPF_REG_0];
u8 t1 = MIPS_R_T6;
u8 t2 = MIPS_R_T7;
LLSC_sync(ctx);
emit(ctx, lld, t1, off, dst);
emit(ctx, bne, t1, r0, 12);
emit(ctx, move, t2, src); /* Delay slot */
emit(ctx, scd, t2, off, dst);
emit(ctx, LLSC_beqz, t2, -20 - LLSC_offset);
emit(ctx, move, r0, t1); /* Delay slot */
clobber_reg(ctx, r0);
}
/* Function call */
static int emit_call(struct jit_context *ctx, const struct bpf_insn *insn)
{
u8 zx = bpf2mips64[JIT_REG_ZX];
u8 tmp = MIPS_R_T6;
bool fixed;
u64 addr;
/* Decode the call address */
if (bpf_jit_get_func_addr(ctx->program, insn, false,
&addr, &fixed) < 0)
return -1;
if (!fixed)
return -1;
/* Push caller-saved registers on stack */
push_regs(ctx, ctx->clobbered & JIT_CALLER_REGS, 0, 0);
/* Emit function call */
emit_mov_i64(ctx, tmp, addr & JALR_MASK);
emit(ctx, jalr, MIPS_R_RA, tmp);
emit(ctx, nop); /* Delay slot */
/* Restore caller-saved registers */
pop_regs(ctx, ctx->clobbered & JIT_CALLER_REGS, 0, 0);
/* Re-initialize the JIT zero-extension register if accessed */
if (ctx->accessed & BIT(JIT_REG_ZX)) {
emit(ctx, daddiu, zx, MIPS_R_ZERO, -1);
emit(ctx, dsrl32, zx, zx, 0);
}
clobber_reg(ctx, MIPS_R_RA);
clobber_reg(ctx, MIPS_R_V0);
clobber_reg(ctx, MIPS_R_V1);
return 0;
}
/* Function tail call */
static int emit_tail_call(struct jit_context *ctx)
{
u8 ary = bpf2mips64[BPF_REG_2];
u8 ind = bpf2mips64[BPF_REG_3];
u8 tcc = bpf2mips64[JIT_REG_TC];
u8 tmp = MIPS_R_T6;
int off;
/*
* Tail call:
* eBPF R1 - function argument (context ptr), passed in a0-a1
* eBPF R2 - ptr to object with array of function entry points
* eBPF R3 - array index of function to be called
*/
/* if (ind >= ary->map.max_entries) goto out */
off = offsetof(struct bpf_array, map.max_entries);
if (off > 0x7fff)
return -1;
emit(ctx, lwu, tmp, off, ary); /* tmp = ary->map.max_entrs*/
emit(ctx, sltu, tmp, ind, tmp); /* tmp = ind < t1 */
emit(ctx, beqz, tmp, get_offset(ctx, 1)); /* PC += off(1) if tmp == 0*/
/* if (--TCC < 0) goto out */
emit(ctx, daddiu, tcc, tcc, -1); /* tcc-- (delay slot) */
emit(ctx, bltz, tcc, get_offset(ctx, 1)); /* PC += off(1) if tcc < 0 */
/* (next insn delay slot) */
/* prog = ary->ptrs[ind] */
off = offsetof(struct bpf_array, ptrs);
if (off > 0x7fff)
return -1;
emit(ctx, dsll, tmp, ind, 3); /* tmp = ind << 3 */
emit(ctx, daddu, tmp, tmp, ary); /* tmp += ary */
emit(ctx, ld, tmp, off, tmp); /* tmp = *(tmp + off) */
/* if (prog == 0) goto out */
emit(ctx, beqz, tmp, get_offset(ctx, 1)); /* PC += off(1) if tmp == 0*/
emit(ctx, nop); /* Delay slot */
/* func = prog->bpf_func + 8 (prologue skip offset) */
off = offsetof(struct bpf_prog, bpf_func);
if (off > 0x7fff)
return -1;
emit(ctx, ld, tmp, off, tmp); /* tmp = *(tmp + off) */
emit(ctx, daddiu, tmp, tmp, JIT_TCALL_SKIP); /* tmp += skip (4) */
/* goto func */
build_epilogue(ctx, tmp);
access_reg(ctx, JIT_REG_TC);
return 0;
}
/*
* Stack frame layout for a JITed program (stack grows down).
*
* Higher address : Previous stack frame :
* +===========================+ <--- MIPS sp before call
* | Callee-saved registers, |
* | including RA and FP |
* +---------------------------+ <--- eBPF FP (MIPS fp)
* | Local eBPF variables |
* | allocated by program |
* +---------------------------+
* | Reserved for caller-saved |
* | registers |
* Lower address +===========================+ <--- MIPS sp
*/
/* Build program prologue to set up the stack and registers */
void build_prologue(struct jit_context *ctx)
{
u8 fp = bpf2mips64[BPF_REG_FP];
u8 tc = bpf2mips64[JIT_REG_TC];
u8 zx = bpf2mips64[JIT_REG_ZX];
int stack, saved, locals, reserved;
/*
* In the unlikely event that the TCC limit is raised to more
* than 16 bits, it is clamped to the maximum value allowed for
* the generated code (0xffff). It is better fail to compile
* instead of degrading gracefully.
*/
BUILD_BUG_ON(MAX_TAIL_CALL_CNT > 0xffff);
/*
* The first instruction initializes the tail call count register.
* On a tail call, the calling function jumps into the prologue
* after this instruction.
*/
emit(ctx, ori, tc, MIPS_R_ZERO, MAX_TAIL_CALL_CNT);
/* === Entry-point for tail calls === */
/*
* If the eBPF frame pointer and tail call count registers were
* accessed they must be preserved. Mark them as clobbered here
* to save and restore them on the stack as needed.
*/
if (ctx->accessed & BIT(BPF_REG_FP))
clobber_reg(ctx, fp);
if (ctx->accessed & BIT(JIT_REG_TC))
clobber_reg(ctx, tc);
if (ctx->accessed & BIT(JIT_REG_ZX))
clobber_reg(ctx, zx);
/* Compute the stack space needed for callee-saved registers */
saved = hweight32(ctx->clobbered & JIT_CALLEE_REGS) * sizeof(u64);
saved = ALIGN(saved, MIPS_STACK_ALIGNMENT);
/* Stack space used by eBPF program local data */
locals = ALIGN(ctx->program->aux->stack_depth, MIPS_STACK_ALIGNMENT);
/*
* If we are emitting function calls, reserve extra stack space for
* caller-saved registers needed by the JIT. The required space is
* computed automatically during resource usage discovery (pass 1).
*/
reserved = ctx->stack_used;
/* Allocate the stack frame */
stack = ALIGN(saved + locals + reserved, MIPS_STACK_ALIGNMENT);
if (stack)
emit(ctx, daddiu, MIPS_R_SP, MIPS_R_SP, -stack);
/* Store callee-saved registers on stack */
push_regs(ctx, ctx->clobbered & JIT_CALLEE_REGS, 0, stack - saved);
/* Initialize the eBPF frame pointer if accessed */
if (ctx->accessed & BIT(BPF_REG_FP))
emit(ctx, daddiu, fp, MIPS_R_SP, stack - saved);
/* Initialize the ePF JIT zero-extension register if accessed */
if (ctx->accessed & BIT(JIT_REG_ZX)) {
emit(ctx, daddiu, zx, MIPS_R_ZERO, -1);
emit(ctx, dsrl32, zx, zx, 0);
}
ctx->saved_size = saved;
ctx->stack_size = stack;
}
/* Build the program epilogue to restore the stack and registers */
void build_epilogue(struct jit_context *ctx, int dest_reg)
{
/* Restore callee-saved registers from stack */
pop_regs(ctx, ctx->clobbered & JIT_CALLEE_REGS, 0,
ctx->stack_size - ctx->saved_size);
/* Release the stack frame */
if (ctx->stack_size)
emit(ctx, daddiu, MIPS_R_SP, MIPS_R_SP, ctx->stack_size);
/* Jump to return address and sign-extend the 32-bit return value */
emit(ctx, jr, dest_reg);
emit(ctx, sll, MIPS_R_V0, MIPS_R_V0, 0); /* Delay slot */
}
/* Build one eBPF instruction */
int build_insn(const struct bpf_insn *insn, struct jit_context *ctx)
{
u8 dst = bpf2mips64[insn->dst_reg];
u8 src = bpf2mips64[insn->src_reg];
u8 res = bpf2mips64[BPF_REG_0];
u8 code = insn->code;
s16 off = insn->off;
s32 imm = insn->imm;
s32 val, rel;
u8 alu, jmp;
switch (code) {
/* ALU operations */
/* dst = imm */
case BPF_ALU | BPF_MOV | BPF_K:
emit_mov_i(ctx, dst, imm);
emit_zext_ver(ctx, dst);
break;
/* dst = src */
case BPF_ALU | BPF_MOV | BPF_X:
if (imm == 1) {
/* Special mov32 for zext */
emit_zext(ctx, dst);
} else {
emit_mov_r(ctx, dst, src);
emit_zext_ver(ctx, dst);
}
break;
/* dst = -dst */
case BPF_ALU | BPF_NEG:
emit_sext(ctx, dst, dst);
emit_alu_i(ctx, dst, 0, BPF_NEG);
emit_zext_ver(ctx, dst);
break;
/* dst = dst & imm */
/* dst = dst | imm */
/* dst = dst ^ imm */
/* dst = dst << imm */
case BPF_ALU | BPF_OR | BPF_K:
case BPF_ALU | BPF_AND | BPF_K:
case BPF_ALU | BPF_XOR | BPF_K:
case BPF_ALU | BPF_LSH | BPF_K:
if (!valid_alu_i(BPF_OP(code), imm)) {
emit_mov_i(ctx, MIPS_R_T4, imm);
emit_alu_r(ctx, dst, MIPS_R_T4, BPF_OP(code));
} else if (rewrite_alu_i(BPF_OP(code), imm, &alu, &val)) {
emit_alu_i(ctx, dst, val, alu);
}
emit_zext_ver(ctx, dst);
break;
/* dst = dst >> imm */
/* dst = dst >> imm (arithmetic) */
/* dst = dst + imm */
/* dst = dst - imm */
/* dst = dst * imm */
/* dst = dst / imm */
/* dst = dst % imm */
case BPF_ALU | BPF_RSH | BPF_K:
case BPF_ALU | BPF_ARSH | BPF_K:
case BPF_ALU | BPF_ADD | BPF_K:
case BPF_ALU | BPF_SUB | BPF_K:
case BPF_ALU | BPF_MUL | BPF_K:
case BPF_ALU | BPF_DIV | BPF_K:
case BPF_ALU | BPF_MOD | BPF_K:
if (!valid_alu_i(BPF_OP(code), imm)) {
emit_sext(ctx, dst, dst);
emit_mov_i(ctx, MIPS_R_T4, imm);
emit_alu_r(ctx, dst, MIPS_R_T4, BPF_OP(code));
} else if (rewrite_alu_i(BPF_OP(code), imm, &alu, &val)) {
emit_sext(ctx, dst, dst);
emit_alu_i(ctx, dst, val, alu);
}
emit_zext_ver(ctx, dst);
break;
/* dst = dst & src */
/* dst = dst | src */
/* dst = dst ^ src */
/* dst = dst << src */
case BPF_ALU | BPF_AND | BPF_X:
case BPF_ALU | BPF_OR | BPF_X:
case BPF_ALU | BPF_XOR | BPF_X:
case BPF_ALU | BPF_LSH | BPF_X:
emit_alu_r(ctx, dst, src, BPF_OP(code));
emit_zext_ver(ctx, dst);
break;
/* dst = dst >> src */
/* dst = dst >> src (arithmetic) */
/* dst = dst + src */
/* dst = dst - src */
/* dst = dst * src */
/* dst = dst / src */
/* dst = dst % src */
case BPF_ALU | BPF_RSH | BPF_X:
case BPF_ALU | BPF_ARSH | BPF_X:
case BPF_ALU | BPF_ADD | BPF_X:
case BPF_ALU | BPF_SUB | BPF_X:
case BPF_ALU | BPF_MUL | BPF_X:
case BPF_ALU | BPF_DIV | BPF_X:
case BPF_ALU | BPF_MOD | BPF_X:
emit_sext(ctx, dst, dst);
emit_sext(ctx, MIPS_R_T4, src);
emit_alu_r(ctx, dst, MIPS_R_T4, BPF_OP(code));
emit_zext_ver(ctx, dst);
break;
/* dst = imm (64-bit) */
case BPF_ALU64 | BPF_MOV | BPF_K:
emit_mov_i(ctx, dst, imm);
break;
/* dst = src (64-bit) */
case BPF_ALU64 | BPF_MOV | BPF_X:
emit_mov_r(ctx, dst, src);
break;
/* dst = -dst (64-bit) */
case BPF_ALU64 | BPF_NEG:
emit_alu_i64(ctx, dst, 0, BPF_NEG);
break;
/* dst = dst & imm (64-bit) */
/* dst = dst | imm (64-bit) */
/* dst = dst ^ imm (64-bit) */
/* dst = dst << imm (64-bit) */
/* dst = dst >> imm (64-bit) */
/* dst = dst >> imm ((64-bit, arithmetic) */
/* dst = dst + imm (64-bit) */
/* dst = dst - imm (64-bit) */
/* dst = dst * imm (64-bit) */
/* dst = dst / imm (64-bit) */
/* dst = dst % imm (64-bit) */
case BPF_ALU64 | BPF_AND | BPF_K:
case BPF_ALU64 | BPF_OR | BPF_K:
case BPF_ALU64 | BPF_XOR | BPF_K:
case BPF_ALU64 | BPF_LSH | BPF_K:
case BPF_ALU64 | BPF_RSH | BPF_K:
case BPF_ALU64 | BPF_ARSH | BPF_K:
case BPF_ALU64 | BPF_ADD | BPF_K:
case BPF_ALU64 | BPF_SUB | BPF_K:
case BPF_ALU64 | BPF_MUL | BPF_K:
case BPF_ALU64 | BPF_DIV | BPF_K:
case BPF_ALU64 | BPF_MOD | BPF_K:
if (!valid_alu_i(BPF_OP(code), imm)) {
emit_mov_i(ctx, MIPS_R_T4, imm);
emit_alu_r64(ctx, dst, MIPS_R_T4, BPF_OP(code));
} else if (rewrite_alu_i(BPF_OP(code), imm, &alu, &val)) {
emit_alu_i64(ctx, dst, val, alu);
}
break;
/* dst = dst & src (64-bit) */
/* dst = dst | src (64-bit) */
/* dst = dst ^ src (64-bit) */
/* dst = dst << src (64-bit) */
/* dst = dst >> src (64-bit) */
/* dst = dst >> src (64-bit, arithmetic) */
/* dst = dst + src (64-bit) */
/* dst = dst - src (64-bit) */
/* dst = dst * src (64-bit) */
/* dst = dst / src (64-bit) */
/* dst = dst % src (64-bit) */
case BPF_ALU64 | BPF_AND | BPF_X:
case BPF_ALU64 | BPF_OR | BPF_X:
case BPF_ALU64 | BPF_XOR | BPF_X:
case BPF_ALU64 | BPF_LSH | BPF_X:
case BPF_ALU64 | BPF_RSH | BPF_X:
case BPF_ALU64 | BPF_ARSH | BPF_X:
case BPF_ALU64 | BPF_ADD | BPF_X:
case BPF_ALU64 | BPF_SUB | BPF_X:
case BPF_ALU64 | BPF_MUL | BPF_X:
case BPF_ALU64 | BPF_DIV | BPF_X:
case BPF_ALU64 | BPF_MOD | BPF_X:
emit_alu_r64(ctx, dst, src, BPF_OP(code));
break;
/* dst = htole(dst) */
/* dst = htobe(dst) */
case BPF_ALU | BPF_END | BPF_FROM_LE:
case BPF_ALU | BPF_END | BPF_FROM_BE:
if (BPF_SRC(code) ==
#ifdef __BIG_ENDIAN
BPF_FROM_LE
#else
BPF_FROM_BE
#endif
)
emit_bswap_r64(ctx, dst, imm);
else
emit_trunc_r64(ctx, dst, imm);
break;
/* dst = imm64 */
case BPF_LD | BPF_IMM | BPF_DW:
emit_mov_i64(ctx, dst, (u32)imm | ((u64)insn[1].imm << 32));
return 1;
/* LDX: dst = *(size *)(src + off) */
case BPF_LDX | BPF_MEM | BPF_W:
case BPF_LDX | BPF_MEM | BPF_H:
case BPF_LDX | BPF_MEM | BPF_B:
case BPF_LDX | BPF_MEM | BPF_DW:
emit_ldx(ctx, dst, src, off, BPF_SIZE(code));
break;
/* ST: *(size *)(dst + off) = imm */
case BPF_ST | BPF_MEM | BPF_W:
case BPF_ST | BPF_MEM | BPF_H:
case BPF_ST | BPF_MEM | BPF_B:
case BPF_ST | BPF_MEM | BPF_DW:
emit_mov_i(ctx, MIPS_R_T4, imm);
emit_stx(ctx, dst, MIPS_R_T4, off, BPF_SIZE(code));
break;
/* STX: *(size *)(dst + off) = src */
case BPF_STX | BPF_MEM | BPF_W:
case BPF_STX | BPF_MEM | BPF_H:
case BPF_STX | BPF_MEM | BPF_B:
case BPF_STX | BPF_MEM | BPF_DW:
emit_stx(ctx, dst, src, off, BPF_SIZE(code));
break;
/* Speculation barrier */
case BPF_ST | BPF_NOSPEC:
break;
/* Atomics */
case BPF_STX | BPF_ATOMIC | BPF_W:
case BPF_STX | BPF_ATOMIC | BPF_DW:
switch (imm) {
case BPF_ADD:
case BPF_ADD | BPF_FETCH:
case BPF_AND:
case BPF_AND | BPF_FETCH:
case BPF_OR:
case BPF_OR | BPF_FETCH:
case BPF_XOR:
case BPF_XOR | BPF_FETCH:
case BPF_XCHG:
if (BPF_SIZE(code) == BPF_DW) {
emit_atomic_r64(ctx, dst, src, off, imm);
} else if (imm & BPF_FETCH) {
u8 tmp = dst;
if (src == dst) { /* Don't overwrite dst */
emit_mov_r(ctx, MIPS_R_T4, dst);
tmp = MIPS_R_T4;
}
emit_sext(ctx, src, src);
emit_atomic_r(ctx, tmp, src, off, imm);
emit_zext_ver(ctx, src);
} else { /* 32-bit, no fetch */
emit_sext(ctx, MIPS_R_T4, src);
emit_atomic_r(ctx, dst, MIPS_R_T4, off, imm);
}
break;
case BPF_CMPXCHG:
if (BPF_SIZE(code) == BPF_DW) {
emit_cmpxchg_r64(ctx, dst, src, off);
} else {
u8 tmp = res;
if (res == dst) /* Don't overwrite dst */
tmp = MIPS_R_T4;
emit_sext(ctx, tmp, res);
emit_sext(ctx, MIPS_R_T5, src);
emit_cmpxchg_r(ctx, dst, MIPS_R_T5, tmp, off);
if (res == dst) /* Restore result */
emit_mov_r(ctx, res, MIPS_R_T4);
/* Result zext inserted by verifier */
}
break;
default:
goto notyet;
}
break;
/* PC += off if dst == src */
/* PC += off if dst != src */
/* PC += off if dst & src */
/* PC += off if dst > src */
/* PC += off if dst >= src */
/* PC += off if dst < src */
/* PC += off if dst <= src */
/* PC += off if dst > src (signed) */
/* PC += off if dst >= src (signed) */
/* PC += off if dst < src (signed) */
/* PC += off if dst <= src (signed) */
case BPF_JMP32 | BPF_JEQ | BPF_X:
case BPF_JMP32 | BPF_JNE | BPF_X:
case BPF_JMP32 | BPF_JSET | 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:
if (off == 0)
break;
setup_jmp_r(ctx, dst == src, BPF_OP(code), off, &jmp, &rel);
emit_sext(ctx, MIPS_R_T4, dst); /* Sign-extended dst */
emit_sext(ctx, MIPS_R_T5, src); /* Sign-extended src */
emit_jmp_r(ctx, MIPS_R_T4, MIPS_R_T5, rel, jmp);
if (finish_jmp(ctx, jmp, off) < 0)
goto toofar;
break;
/* PC += off if dst == imm */
/* PC += off if dst != imm */
/* PC += off if dst & imm */
/* PC += off if dst > imm */
/* PC += off if dst >= imm */
/* PC += off if dst < imm */
/* PC += off if dst <= imm */
/* PC += off if dst > imm (signed) */
/* PC += off if dst >= imm (signed) */
/* PC += off if dst < imm (signed) */
/* PC += off if dst <= imm (signed) */
case BPF_JMP32 | BPF_JEQ | BPF_K:
case BPF_JMP32 | BPF_JNE | BPF_K:
case BPF_JMP32 | BPF_JSET | 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:
if (off == 0)
break;
setup_jmp_i(ctx, imm, 32, BPF_OP(code), off, &jmp, &rel);
emit_sext(ctx, MIPS_R_T4, dst); /* Sign-extended dst */
if (valid_jmp_i(jmp, imm)) {
emit_jmp_i(ctx, MIPS_R_T4, imm, rel, jmp);
} else {
/* Move large immediate to register, sign-extended */
emit_mov_i(ctx, MIPS_R_T5, imm);
emit_jmp_r(ctx, MIPS_R_T4, MIPS_R_T5, rel, jmp);
}
if (finish_jmp(ctx, jmp, off) < 0)
goto toofar;
break;
/* PC += off if dst == src */
/* PC += off if dst != src */
/* PC += off if dst & src */
/* PC += off if dst > src */
/* PC += off if dst >= src */
/* PC += off if dst < src */
/* PC += off if dst <= src */
/* PC += off if dst > src (signed) */
/* PC += off if dst >= src (signed) */
/* PC += off if dst < src (signed) */
/* PC += off if dst <= src (signed) */
case BPF_JMP | BPF_JEQ | BPF_X:
case BPF_JMP | BPF_JNE | BPF_X:
case BPF_JMP | BPF_JSET | 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:
if (off == 0)
break;
setup_jmp_r(ctx, dst == src, BPF_OP(code), off, &jmp, &rel);
emit_jmp_r(ctx, dst, src, rel, jmp);
if (finish_jmp(ctx, jmp, off) < 0)
goto toofar;
break;
/* PC += off if dst == imm */
/* PC += off if dst != imm */
/* PC += off if dst & imm */
/* PC += off if dst > imm */
/* PC += off if dst >= imm */
/* PC += off if dst < imm */
/* PC += off if dst <= imm */
/* PC += off if dst > imm (signed) */
/* PC += off if dst >= imm (signed) */
/* PC += off if dst < imm (signed) */
/* PC += off if dst <= imm (signed) */
case BPF_JMP | BPF_JEQ | BPF_K:
case BPF_JMP | BPF_JNE | BPF_K:
case BPF_JMP | BPF_JSET | 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:
if (off == 0)
break;
setup_jmp_i(ctx, imm, 64, BPF_OP(code), off, &jmp, &rel);
if (valid_jmp_i(jmp, imm)) {
emit_jmp_i(ctx, dst, imm, rel, jmp);
} else {
/* Move large immediate to register */
emit_mov_i(ctx, MIPS_R_T4, imm);
emit_jmp_r(ctx, dst, MIPS_R_T4, rel, jmp);
}
if (finish_jmp(ctx, jmp, off) < 0)
goto toofar;
break;
/* PC += off */
case BPF_JMP | BPF_JA:
if (off == 0)
break;
if (emit_ja(ctx, off) < 0)
goto toofar;
break;
/* Tail call */
case BPF_JMP | BPF_TAIL_CALL:
if (emit_tail_call(ctx) < 0)
goto invalid;
break;
/* Function call */
case BPF_JMP | BPF_CALL:
if (emit_call(ctx, insn) < 0)
goto invalid;
break;
/* Function return */
case BPF_JMP | BPF_EXIT:
/*
* Optimization: when last instruction is EXIT
* simply continue to epilogue.
*/
if (ctx->bpf_index == ctx->program->len - 1)
break;
if (emit_exit(ctx) < 0)
goto toofar;
break;
default:
invalid:
pr_err_once("unknown opcode %02x\n", code);
return -EINVAL;
notyet:
pr_info_once("*** NOT YET: opcode %02x ***\n", code);
return -EFAULT;
toofar:
pr_info_once("*** TOO FAR: jump at %u opcode %02x ***\n",
ctx->bpf_index, code);
return -E2BIG;
}
return 0;
}
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