// SPDX-License-Identifier: GPL-2.0-only
/*
* Just-In-Time compiler for eBPF filters on 32bit ARM
*
* Copyright (c) 2017 Shubham Bansal <illusionist.neo@gmail.com>
* Copyright (c) 2011 Mircea Gherzan <mgherzan@gmail.com>
*/
#include <linux/bpf.h>
#include <linux/bitops.h>
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/filter.h>
#include <linux/netdevice.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/if_vlan.h>
#include <asm/cacheflush.h>
#include <asm/hwcap.h>
#include <asm/opcodes.h>
#include <asm/system_info.h>
#include "bpf_jit_32.h"
/*
* eBPF prog stack layout:
*
* high
* original ARM_SP => +-----+
* | | callee saved registers
* +-----+ <= (BPF_FP + SCRATCH_SIZE)
* | ... | eBPF JIT scratch space
* eBPF fp register => +-----+
* (BPF_FP) | ... | eBPF prog stack
* +-----+
* |RSVD | JIT scratchpad
* current ARM_SP => +-----+ <= (BPF_FP - STACK_SIZE + SCRATCH_SIZE)
* | ... | caller-saved registers
* +-----+
* | ... | arguments passed on stack
* ARM_SP during call => +-----|
* | |
* | ... | Function call stack
* | |
* +-----+
* low
*
* The callee saved registers depends on whether frame pointers are enabled.
* With frame pointers (to be compliant with the ABI):
*
* high
* original ARM_SP => +--------------+ \
* | pc | |
* current ARM_FP => +--------------+ } callee saved registers
* |r4-r9,fp,ip,lr| |
* +--------------+ /
* low
*
* Without frame pointers:
*
* high
* original ARM_SP => +--------------+
* | r4-r9,fp,lr | callee saved registers
* current ARM_FP => +--------------+
* low
*
* When popping registers off the stack at the end of a BPF function, we
* reference them via the current ARM_FP register.
*
* Some eBPF operations are implemented via a call to a helper function.
* Such calls are "invisible" in the eBPF code, so it is up to the calling
* program to preserve any caller-saved ARM registers during the call. The
* JIT emits code to push and pop those registers onto the stack, immediately
* above the callee stack frame.
*/
#define CALLEE_MASK (1 << ARM_R4 | 1 << ARM_R5 | 1 << ARM_R6 | \
1 << ARM_R7 | 1 << ARM_R8 | 1 << ARM_R9 | \
1 << ARM_FP)
#define CALLEE_PUSH_MASK (CALLEE_MASK | 1 << ARM_LR)
#define CALLEE_POP_MASK (CALLEE_MASK | 1 << ARM_PC)
#define CALLER_MASK (1 << ARM_R0 | 1 << ARM_R1 | 1 << ARM_R2 | 1 << ARM_R3)
enum {
/* Stack layout - these are offsets from (top of stack - 4) */
BPF_R2_HI,
BPF_R2_LO,
BPF_R3_HI,
BPF_R3_LO,
BPF_R4_HI,
BPF_R4_LO,
BPF_R5_HI,
BPF_R5_LO,
BPF_R7_HI,
BPF_R7_LO,
BPF_R8_HI,
BPF_R8_LO,
BPF_R9_HI,
BPF_R9_LO,
BPF_FP_HI,
BPF_FP_LO,
BPF_TC_HI,
BPF_TC_LO,
BPF_AX_HI,
BPF_AX_LO,
/* Stack space for BPF_REG_2, BPF_REG_3, BPF_REG_4,
* BPF_REG_5, BPF_REG_7, BPF_REG_8, BPF_REG_9,
* BPF_REG_FP and Tail call counts.
*/
BPF_JIT_SCRATCH_REGS,
};
/*
* Negative "register" values indicate the register is stored on the stack
* and are the offset from the top of the eBPF JIT scratch space.
*/
#define STACK_OFFSET(k) (-4 - (k) * 4)
#define SCRATCH_SIZE (BPF_JIT_SCRATCH_REGS * 4)
#ifdef CONFIG_FRAME_POINTER
#define EBPF_SCRATCH_TO_ARM_FP(x) ((x) - 4 * hweight16(CALLEE_PUSH_MASK) - 4)
#else
#define EBPF_SCRATCH_TO_ARM_FP(x) (x)
#endif
#define TMP_REG_1 (MAX_BPF_JIT_REG + 0) /* TEMP Register 1 */
#define TMP_REG_2 (MAX_BPF_JIT_REG + 1) /* TEMP Register 2 */
#define TCALL_CNT (MAX_BPF_JIT_REG + 2) /* Tail Call Count */
#define FLAG_IMM_OVERFLOW (1 << 0)
/*
* Map eBPF registers to ARM 32bit registers or stack scratch space.
*
* 1. First argument is passed using the arm 32bit registers and rest of the
* arguments are passed on stack scratch space.
* 2. First callee-saved argument is mapped to arm 32 bit registers and rest
* arguments are mapped to scratch space on stack.
* 3. We need two 64 bit temp registers to do complex operations on eBPF
* registers.
*
* As the eBPF registers are all 64 bit registers and arm has only 32 bit
* registers, we have to map each eBPF registers with two arm 32 bit regs or
* scratch memory space and we have to build eBPF 64 bit register from those.
*
*/
static const s8 bpf2a32[][2] = {
/* return value from in-kernel function, and exit value from eBPF */
[BPF_REG_0] = {ARM_R1, ARM_R0},
/* arguments from eBPF program to in-kernel function */
[BPF_REG_1] = {ARM_R3, ARM_R2},
/* Stored on stack scratch space */
[BPF_REG_2] = {STACK_OFFSET(BPF_R2_HI), STACK_OFFSET(BPF_R2_LO)},
[BPF_REG_3] = {STACK_OFFSET(BPF_R3_HI), STACK_OFFSET(BPF_R3_LO)},
[BPF_REG_4] = {STACK_OFFSET(BPF_R4_HI), STACK_OFFSET(BPF_R4_LO)},
[BPF_REG_5] = {STACK_OFFSET(BPF_R5_HI), STACK_OFFSET(BPF_R5_LO)},
/* callee saved registers that in-kernel function will preserve */
[BPF_REG_6] = {ARM_R5, ARM_R4},
/* Stored on stack scratch space */
[BPF_REG_7] = {STACK_OFFSET(BPF_R7_HI), STACK_OFFSET(BPF_R7_LO)},
[BPF_REG_8] = {STACK_OFFSET(BPF_R8_HI), STACK_OFFSET(BPF_R8_LO)},
[BPF_REG_9] = {STACK_OFFSET(BPF_R9_HI), STACK_OFFSET(BPF_R9_LO)},
/* Read only Frame Pointer to access Stack */
[BPF_REG_FP] = {STACK_OFFSET(BPF_FP_HI), STACK_OFFSET(BPF_FP_LO)},
/* Temporary Register for BPF JIT, can be used
* for constant blindings and others.
*/
[TMP_REG_1] = {ARM_R7, ARM_R6},
[TMP_REG_2] = {ARM_R9, ARM_R8},
/* Tail call count. Stored on stack scratch space. */
[TCALL_CNT] = {STACK_OFFSET(BPF_TC_HI), STACK_OFFSET(BPF_TC_LO)},
/* temporary register for blinding constants.
* Stored on stack scratch space.
*/
[BPF_REG_AX] = {STACK_OFFSET(BPF_AX_HI), STACK_OFFSET(BPF_AX_LO)},
};
#define dst_lo dst[1]
#define dst_hi dst[0]
#define src_lo src[1]
#define src_hi src[0]
/*
* JIT Context:
*
* prog : bpf_prog
* idx : index of current last JITed instruction.
* prologue_bytes : bytes used in prologue.
* epilogue_offset : offset of epilogue starting.
* offsets : array of eBPF instruction offsets in
* JITed code.
* target : final JITed code.
* epilogue_bytes : no of bytes used in epilogue.
* imm_count : no of immediate counts used for global
* variables.
* imms : array of global variable addresses.
*/
struct jit_ctx {
const struct bpf_prog *prog;
unsigned int idx;
unsigned int prologue_bytes;
unsigned int epilogue_offset;
unsigned int cpu_architecture;
u32 flags;
u32 *offsets;
u32 *target;
u32 stack_size;
#if __LINUX_ARM_ARCH__ < 7
u16 epilogue_bytes;
u16 imm_count;
u32 *imms;
#endif
};
/*
* Wrappers which handle both OABI and EABI and assures Thumb2 interworking
* (where the assembly routines like __aeabi_uidiv could cause problems).
*/
static u32 jit_udiv32(u32 dividend, u32 divisor)
{
return dividend / divisor;
}
static u32 jit_mod32(u32 dividend, u32 divisor)
{
return dividend % divisor;
}
static inline void _emit(int cond, u32 inst, struct jit_ctx *ctx)
{
inst |= (cond << 28);
inst = __opcode_to_mem_arm(inst);
if (ctx->target != NULL)
ctx->target[ctx->idx] = inst;
ctx->idx++;
}
/*
* Emit an instruction that will be executed unconditionally.
*/
static inline void emit(u32 inst, struct jit_ctx *ctx)
{
_emit(ARM_COND_AL, inst, ctx);
}
/*
* This is rather horrid, but necessary to convert an integer constant
* to an immediate operand for the opcodes, and be able to detect at
* build time whether the constant can't be converted (iow, usable in
* BUILD_BUG_ON()).
*/
#define imm12val(v, s) (rol32(v, (s)) | (s) << 7)
#define const_imm8m(x) \
({ int r; \
u32 v = (x); \
if (!(v & ~0x000000ff)) \
r = imm12val(v, 0); \
else if (!(v & ~0xc000003f)) \
r = imm12val(v, 2); \
else if (!(v & ~0xf000000f)) \
r = imm12val(v, 4); \
else if (!(v & ~0xfc000003)) \
r = imm12val(v, 6); \
else if (!(v & ~0xff000000)) \
r = imm12val(v, 8); \
else if (!(v & ~0x3fc00000)) \
r = imm12val(v, 10); \
else if (!(v & ~0x0ff00000)) \
r = imm12val(v, 12); \
else if (!(v & ~0x03fc0000)) \
r = imm12val(v, 14); \
else if (!(v & ~0x00ff0000)) \
r = imm12val(v, 16); \
else if (!(v & ~0x003fc000)) \
r = imm12val(v, 18); \
else if (!(v & ~0x000ff000)) \
r = imm12val(v, 20); \
else if (!(v & ~0x0003fc00)) \
r = imm12val(v, 22); \
else if (!(v & ~0x0000ff00)) \
r = imm12val(v, 24); \
else if (!(v & ~0x00003fc0)) \
r = imm12val(v, 26); \
else if (!(v & ~0x00000ff0)) \
r = imm12val(v, 28); \
else if (!(v & ~0x000003fc)) \
r = imm12val(v, 30); \
else \
r = -1; \
r; })
/*
* Checks if immediate value can be converted to imm12(12 bits) value.
*/
static int imm8m(u32 x)
{
u32 rot;
for (rot = 0; rot < 16; rot++)
if ((x & ~ror32(0xff, 2 * rot)) == 0)
return rol32(x, 2 * rot) | (rot << 8);
return -1;
}
#define imm8m(x) (__builtin_constant_p(x) ? const_imm8m(x) : imm8m(x))
static u32 arm_bpf_ldst_imm12(u32 op, u8 rt, u8 rn, s16 imm12)
{
op |= rt << 12 | rn << 16;
if (imm12 >= 0)
op |= ARM_INST_LDST__U;
else
imm12 = -imm12;
return op | (imm12 & ARM_INST_LDST__IMM12);
}
static u32 arm_bpf_ldst_imm8(u32 op, u8 rt, u8 rn, s16 imm8)
{
op |= rt << 12 | rn << 16;
if (imm8 >= 0)
op |= ARM_INST_LDST__U;
else
imm8 = -imm8;
return op | (imm8 & 0xf0) << 4 | (imm8 & 0x0f);
}
#define ARM_LDR_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_LDR_I, rt, rn, off)
#define ARM_LDRB_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_LDRB_I, rt, rn, off)
#define ARM_LDRD_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_LDRD_I, rt, rn, off)
#define ARM_LDRH_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_LDRH_I, rt, rn, off)
#define ARM_STR_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_STR_I, rt, rn, off)
#define ARM_STRB_I(rt, rn, off) arm_bpf_ldst_imm12(ARM_INST_STRB_I, rt, rn, off)
#define ARM_STRD_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_STRD_I, rt, rn, off)
#define ARM_STRH_I(rt, rn, off) arm_bpf_ldst_imm8(ARM_INST_STRH_I, rt, rn, off)
/*
* Initializes the JIT space with undefined 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++ = __opcode_to_mem_arm(ARM_INST_UDF);
}
#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5)
/* EABI requires the stack to be aligned to 64-bit boundaries */
#define STACK_ALIGNMENT 8
#else
/* Stack must be aligned to 32-bit boundaries */
#define STACK_ALIGNMENT 4
#endif
/* total stack size used in JITed code */
#define _STACK_SIZE (ctx->prog->aux->stack_depth + SCRATCH_SIZE)
#define STACK_SIZE ALIGN(_STACK_SIZE, STACK_ALIGNMENT)
#if __LINUX_ARM_ARCH__ < 7
static u16 imm_offset(u32 k, struct jit_ctx *ctx)
{
unsigned int i = 0, offset;
u16 imm;
/* on the "fake" run we just count them (duplicates included) */
if (ctx->target == NULL) {
ctx->imm_count++;
return 0;
}
while ((i < ctx->imm_count) && ctx->imms[i]) {
if (ctx->imms[i] == k)
break;
i++;
}
if (ctx->imms[i] == 0)
ctx->imms[i] = k;
/* constants go just after the epilogue */
offset = ctx->offsets[ctx->prog->len - 1] * 4;
offset += ctx->prologue_bytes;
offset += ctx->epilogue_bytes;
offset += i * 4;
ctx->target[offset / 4] = k;
/* PC in ARM mode == address of the instruction + 8 */
imm = offset - (8 + ctx->idx * 4);
if (imm & ~0xfff) {
/*
* literal pool is too far, signal it into flags. we
* can only detect it on the second pass unfortunately.
*/
ctx->flags |= FLAG_IMM_OVERFLOW;
return 0;
}
return imm;
}
#endif /* __LINUX_ARM_ARCH__ */
static inline int bpf2a32_offset(int bpf_to, int bpf_from,
const struct jit_ctx *ctx) {
int to, from;
if (ctx->target == NULL)
return 0;
to = ctx->offsets[bpf_to];
from = ctx->offsets[bpf_from];
return to - from - 1;
}
/*
* Move an immediate that's not an imm8m to a core register.
*/
static inline void emit_mov_i_no8m(const u8 rd, u32 val, struct jit_ctx *ctx)
{
#if __LINUX_ARM_ARCH__ < 7
emit(ARM_LDR_I(rd, ARM_PC, imm_offset(val, ctx)), ctx);
#else
emit(ARM_MOVW(rd, val & 0xffff), ctx);
if (val > 0xffff)
emit(ARM_MOVT(rd, val >> 16), ctx);
#endif
}
static inline void emit_mov_i(const u8 rd, u32 val, struct jit_ctx *ctx)
{
int imm12 = imm8m(val);
if (imm12 >= 0)
emit(ARM_MOV_I(rd, imm12), ctx);
else
emit_mov_i_no8m(rd, val, ctx);
}
static void emit_bx_r(u8 tgt_reg, struct jit_ctx *ctx)
{
if (elf_hwcap & HWCAP_THUMB)
emit(ARM_BX(tgt_reg), ctx);
else
emit(ARM_MOV_R(ARM_PC, tgt_reg), ctx);
}
static inline void emit_blx_r(u8 tgt_reg, struct jit_ctx *ctx)
{
#if __LINUX_ARM_ARCH__ < 5
emit(ARM_MOV_R(ARM_LR, ARM_PC), ctx);
emit_bx_r(tgt_reg, ctx);
#else
emit(ARM_BLX_R(tgt_reg), ctx);
#endif
}
static inline int epilogue_offset(const struct jit_ctx *ctx)
{
int to, from;
/* No need for 1st dummy run */
if (ctx->target == NULL)
return 0;
to = ctx->epilogue_offset;
from = ctx->idx;
return to - from - 2;
}
static inline void emit_udivmod(u8 rd, u8 rm, u8 rn, struct jit_ctx *ctx, u8 op)
{
const int exclude_mask = BIT(ARM_R0) | BIT(ARM_R1);
const s8 *tmp = bpf2a32[TMP_REG_1];
#if __LINUX_ARM_ARCH__ == 7
if (elf_hwcap & HWCAP_IDIVA) {
if (op == BPF_DIV)
emit(ARM_UDIV(rd, rm, rn), ctx);
else {
emit(ARM_UDIV(ARM_IP, rm, rn), ctx);
emit(ARM_MLS(rd, rn, ARM_IP, rm), ctx);
}
return;
}
#endif
/*
* For BPF_ALU | BPF_DIV | BPF_K instructions
* As ARM_R1 and ARM_R0 contains 1st argument of bpf
* function, we need to save it on caller side to save
* it from getting destroyed within callee.
* After the return from the callee, we restore ARM_R0
* ARM_R1.
*/
if (rn != ARM_R1) {
emit(ARM_MOV_R(tmp[0], ARM_R1), ctx);
emit(ARM_MOV_R(ARM_R1, rn), ctx);
}
if (rm != ARM_R0) {
emit(ARM_MOV_R(tmp[1], ARM_R0), ctx);
emit(ARM_MOV_R(ARM_R0, rm), ctx);
}
/* Push caller-saved registers on stack */
emit(ARM_PUSH(CALLER_MASK & ~exclude_mask), ctx);
/* Call appropriate function */
emit_mov_i(ARM_IP, op == BPF_DIV ?
(u32)jit_udiv32 : (u32)jit_mod32, ctx);
emit_blx_r(ARM_IP, ctx);
/* Restore caller-saved registers from stack */
emit(ARM_POP(CALLER_MASK & ~exclude_mask), ctx);
/* Save return value */
if (rd != ARM_R0)
emit(ARM_MOV_R(rd, ARM_R0), ctx);
/* Restore ARM_R0 and ARM_R1 */
if (rn != ARM_R1)
emit(ARM_MOV_R(ARM_R1, tmp[0]), ctx);
if (rm != ARM_R0)
emit(ARM_MOV_R(ARM_R0, tmp[1]), ctx);
}
/* Is the translated BPF register on stack? */
static bool is_stacked(s8 reg)
{
return reg < 0;
}
/* If a BPF register is on the stack (stk is true), load it to the
* supplied temporary register and return the temporary register
* for subsequent operations, otherwise just use the CPU register.
*/
static s8 arm_bpf_get_reg32(s8 reg, s8 tmp, struct jit_ctx *ctx)
{
if (is_stacked(reg)) {
emit(ARM_LDR_I(tmp, ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg)), ctx);
reg = tmp;
}
return reg;
}
static const s8 *arm_bpf_get_reg64(const s8 *reg, const s8 *tmp,
struct jit_ctx *ctx)
{
if (is_stacked(reg[1])) {
if (__LINUX_ARM_ARCH__ >= 6 ||
ctx->cpu_architecture >= CPU_ARCH_ARMv5TE) {
emit(ARM_LDRD_I(tmp[1], ARM_FP,
EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx);
} else {
emit(ARM_LDR_I(tmp[1], ARM_FP,
EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx);
emit(ARM_LDR_I(tmp[0], ARM_FP,
EBPF_SCRATCH_TO_ARM_FP(reg[0])), ctx);
}
reg = tmp;
}
return reg;
}
/* If a BPF register is on the stack (stk is true), save the register
* back to the stack. If the source register is not the same, then
* move it into the correct register.
*/
static void arm_bpf_put_reg32(s8 reg, s8 src, struct jit_ctx *ctx)
{
if (is_stacked(reg))
emit(ARM_STR_I(src, ARM_FP, EBPF_SCRATCH_TO_ARM_FP(reg)), ctx);
else if (reg != src)
emit(ARM_MOV_R(reg, src), ctx);
}
static void arm_bpf_put_reg64(const s8 *reg, const s8 *src,
struct jit_ctx *ctx)
{
if (is_stacked(reg[1])) {
if (__LINUX_ARM_ARCH__ >= 6 ||
ctx->cpu_architecture >= CPU_ARCH_ARMv5TE) {
emit(ARM_STRD_I(src[1], ARM_FP,
EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx);
} else {
emit(ARM_STR_I(src[1], ARM_FP,
EBPF_SCRATCH_TO_ARM_FP(reg[1])), ctx);
emit(ARM_STR_I(src[0], ARM_FP,
EBPF_SCRATCH_TO_ARM_FP(reg[0])), ctx);
}
} else {
if (reg[1] != src[1])
emit(ARM_MOV_R(reg[1], src[1]), ctx);
if (reg[0] != src[0])
emit(ARM_MOV_R(reg[0], src[0]), ctx);
}
}
static inline void emit_a32_mov_i(const s8 dst, const u32 val,
struct jit_ctx *ctx)
{
const s8 *tmp = bpf2a32[TMP_REG_1];
if (is_stacked(dst)) {
emit_mov_i(tmp[1], val, ctx);
arm_bpf_put_reg32(dst, tmp[1], ctx);
} else {
emit_mov_i(dst, val, ctx);
}
}
static void emit_a32_mov_i64(const s8 dst[], u64 val, struct jit_ctx *ctx)
{
const s8 *tmp = bpf2a32[TMP_REG_1];
const s8 *rd = is_stacked(dst_lo) ? tmp : dst;
emit_mov_i(rd[1], (u32)val, ctx);
emit_mov_i(rd[0], val >> 32, ctx);
arm_bpf_put_reg64(dst, rd, ctx);
}
/* Sign extended move */
static inline void emit_a32_mov_se_i64(const bool is64, const s8 dst[],
const u32 val, struct jit_ctx *ctx) {
u64 val64 = val;
if (is64 && (val & (1<<31)))
val64 |= 0xffffffff00000000ULL;
emit_a32_mov_i64(dst, val64, ctx);
}
static inline void emit_a32_add_r(const u8 dst, const u8 src,
const bool is64, const bool hi,
struct jit_ctx *ctx) {
/* 64 bit :
* adds dst_lo, dst_lo, src_lo
* adc dst_hi, dst_hi, src_hi
* 32 bit :
* add dst_lo, dst_lo, src_lo
*/
if (!hi && is64)
emit(ARM_ADDS_R(dst, dst, src), ctx);
else if (hi && is64)
emit(ARM_ADC_R(dst, dst, src), ctx);
else
emit(ARM_ADD_R(dst, dst, src), ctx);
}
static inline void emit_a32_sub_r(const u8 dst, const u8 src,
const bool is64, const bool hi,
struct jit_ctx *ctx) {
/* 64 bit :
* subs dst_lo, dst_lo, src_lo
* sbc dst_hi, dst_hi, src_hi
* 32 bit :
* sub dst_lo, dst_lo, src_lo
*/
if (!hi && is64)
emit(ARM_SUBS_R(dst, dst, src), ctx);
else if (hi && is64)
emit(ARM_SBC_R(dst, dst, src), ctx);
else
emit(ARM_SUB_R(dst, dst, src), ctx);
}
static inline void emit_alu_r(const u8 dst, const u8 src, const bool is64,
const bool hi, const u8 op, struct jit_ctx *ctx){
switch (BPF_OP(op)) {
/* dst = dst + src */
case BPF_ADD:
emit_a32_add_r(dst, src, is64, hi, ctx);
break;
/* dst = dst - src */
case BPF_SUB:
emit_a32_sub_r(dst, src, is64, hi, ctx);
break;
/* dst = dst | src */
case BPF_OR:
emit(ARM_ORR_R(dst, dst, src), ctx);
break;
/* dst = dst & src */
case BPF_AND:
emit(ARM_AND_R(dst, dst, src), ctx);
break;
/* dst = dst ^ src */
case BPF_XOR:
emit(ARM_EOR_R(dst, dst, src), ctx);
break;
/* dst = dst * src */
case BPF_MUL:
emit(ARM_MUL(dst, dst, src), ctx);
break;
/* dst = dst << src */
case BPF_LSH:
emit(ARM_LSL_R(dst, dst, src), ctx);
break;
/* dst = dst >> src */
case BPF_RSH:
emit(ARM_LSR_R(dst, dst, src), ctx);
break;
/* dst = dst >> src (signed)*/
case BPF_ARSH:
emit(ARM_MOV_SR(dst, dst, SRTYPE_ASR, src), ctx);
break;
}
}
/* ALU operation (64 bit) */
static inline void emit_a32_alu_r64(const bool is64, const s8 dst[],
const s8 src[], struct jit_ctx *ctx,
const u8 op) {
const s8 *tmp = bpf2a32[TMP_REG_1];
const s8 *tmp2 = bpf2a32[TMP_REG_2];
const s8 *rd;
rd = arm_bpf_get_reg64(dst, tmp, ctx);
if (is64) {
const s8 *rs;
rs = arm_bpf_get_reg64(src, tmp2, ctx);
/* ALU operation */
emit_alu_r(rd[1], rs[1], true, false, op, ctx);
emit_alu_r(rd[0], rs[0], true, true, op, ctx);
} else {
s8 rs;
rs = arm_bpf_get_reg32(src_lo, tmp2[1], ctx);
/* ALU operation */
emit_alu_r(rd[1], rs, true, false, op, ctx);
if (!ctx->prog->aux->verifier_zext)
emit_a32_mov_i(rd[0], 0, ctx);
}
arm_bpf_put_reg64(dst, rd, ctx);
}
/* dst = src (4 bytes)*/
static inline void emit_a32_mov_r(const s8 dst, const s8 src,
struct jit_ctx *ctx) {
const s8 *tmp = bpf2a32[TMP_REG_1];
s8 rt;
rt = arm_bpf_get_reg32(src, tmp[0], ctx);
arm_bpf_put_reg32(dst, rt, ctx);
}
/* dst = src */
static inline void emit_a32_mov_r64(const bool is64, const s8 dst[],
const s8 src[],
struct jit_ctx *ctx) {
if (!is64) {
emit_a32_mov_r(dst_lo, src_lo, ctx);
if (!ctx->prog->aux->verifier_zext)
/* Zero out high 4 bytes */
emit_a32_mov_i(dst_hi, 0, ctx);
} else if (__LINUX_ARM_ARCH__ < 6 &&
ctx->cpu_architecture < CPU_ARCH_ARMv5TE) {
/* complete 8 byte move */
emit_a32_mov_r(dst_lo, src_lo, ctx);
emit_a32_mov_r(dst_hi, src_hi, ctx);
} else if (is_stacked(src_lo) && is_stacked(dst_lo)) {
const u8 *tmp = bpf2a32[TMP_REG_1];
emit(ARM_LDRD_I(tmp[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(src_lo)), ctx);
emit(ARM_STRD_I(tmp[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(dst_lo)), ctx);
} else if (is_stacked(src_lo)) {
emit(ARM_LDRD_I(dst[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(src_lo)), ctx);
} else if (is_stacked(dst_lo)) {
emit(ARM_STRD_I(src[1], ARM_FP, EBPF_SCRATCH_TO_ARM_FP(dst_lo)), ctx);
} else {
emit(ARM_MOV_R(dst[0], src[0]), ctx);
emit(ARM_MOV_R(dst[1], src[1]), ctx);
}
}
/* Shift operations */
static inline void emit_a32_alu_i(const s8 dst, const u32 val,
struct jit_ctx *ctx, const u8 op) {
const s8 *tmp = bpf2a32[TMP_REG_1];
s8 rd;
rd = arm_bpf_get_reg32(dst, tmp[0], ctx);
/* Do shift operation */
switch (op) {
case BPF_LSH:
emit(ARM_LSL_I(rd, rd, val), ctx);
break;
case BPF_RSH:
emit(ARM_LSR_I(rd, rd, val), ctx);
break;
case BPF_ARSH:
emit(ARM_ASR_I(rd, rd, val), ctx);
break;
case BPF_NEG:
emit(ARM_RSB_I(rd, rd, val), ctx);
break;
}
arm_bpf_put_reg32(dst, rd, ctx);
}
/* dst = ~dst (64 bit) */
static inline void emit_a32_neg64(const s8 dst[],
struct jit_ctx *ctx){
const s8 *tmp = bpf2a32[TMP_REG_1];
const s8 *rd;
/* Setup Operand */
rd = arm_bpf_get_reg64(dst, tmp, ctx);
/* Do Negate Operation */
emit(ARM_RSBS_I(rd[1], rd[1], 0), ctx);
emit(ARM_RSC_I(rd[0], rd[0], 0), ctx);
arm_bpf_put_reg64(dst, rd, ctx);
}
/* dst = dst << src */
static inline void emit_a32_lsh_r64(const s8 dst[], const s8 src[],
struct jit_ctx *ctx) {
const s8 *tmp = bpf2a32[TMP_REG_1];
const s8 *tmp2 = bpf2a32[TMP_REG_2];
const s8 *rd;
s8 rt;
/* Setup Operands */
rt = arm_bpf_get_reg32(src_lo, tmp2[1], ctx);
rd = arm_bpf_get_reg64(dst, tmp, ctx);
/* Do LSH operation */
emit(ARM_SUB_I(ARM_IP, rt, 32), ctx);
emit(ARM_RSB_I(tmp2[0], rt, 32), ctx);
emit(ARM_MOV_SR(ARM_LR, rd[0], SRTYPE_ASL, rt), ctx);
emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[1], SRTYPE_ASL, ARM_IP), ctx);
emit(ARM_ORR_SR(ARM_IP, ARM_LR, rd[1], SRTYPE_LSR, tmp2[0]), ctx);
emit(ARM_MOV_SR(ARM_LR, rd[1], SRTYPE_ASL, rt), ctx);
arm_bpf_put_reg32(dst_lo, ARM_LR, ctx);
arm_bpf_put_reg32(dst_hi, ARM_IP, ctx);
}
/* dst = dst >> src (signed)*/
static inline void emit_a32_arsh_r64(const s8 dst[], const s8 src[],
struct jit_ctx *ctx) {
const s8 *tmp = bpf2a32[TMP_REG_1];
const s8 *tmp2 = bpf2a32[TMP_REG_2];
const s8 *rd;
s8 rt;
/* Setup Operands */
rt = arm_bpf_get_reg32(src_lo, tmp2[1], ctx);
rd = arm_bpf_get_reg64(dst, tmp, ctx);
/* Do the ARSH operation */
emit(ARM_RSB_I(ARM_IP, rt, 32), ctx);
emit(ARM_SUBS_I(tmp2[0], rt, 32), ctx);
emit(ARM_MOV_SR(ARM_LR, rd[1], SRTYPE_LSR, rt), ctx);
emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASL, ARM_IP), ctx);
_emit(ARM_COND_PL,
ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASR, tmp2[0]), ctx);
emit(ARM_MOV_SR(ARM_IP, rd[0], SRTYPE_ASR, rt), ctx);
arm_bpf_put_reg32(dst_lo, ARM_LR, ctx);
arm_bpf_put_reg32(dst_hi, ARM_IP, ctx);
}
/* dst = dst >> src */
static inline void emit_a32_rsh_r64(const s8 dst[], const s8 src[],
struct jit_ctx *ctx) {
const s8 *tmp = bpf2a32[TMP_REG_1];
const s8 *tmp2 = bpf2a32[TMP_REG_2];
const s8 *rd;
s8 rt;
/* Setup Operands */
rt = arm_bpf_get_reg32(src_lo, tmp2[1], ctx);
rd = arm_bpf_get_reg64(dst, tmp, ctx);
/* Do RSH operation */
emit(ARM_RSB_I(ARM_IP, rt, 32), ctx);
emit(ARM_SUBS_I(tmp2[0], rt, 32), ctx);
emit(ARM_MOV_SR(ARM_LR, rd[1], SRTYPE_LSR, rt), ctx);
emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_ASL, ARM_IP), ctx);
emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd[0], SRTYPE_LSR, tmp2[0]), ctx);
emit(ARM_MOV_SR(ARM_IP, rd[0], SRTYPE_LSR, rt), ctx);
arm_bpf_put_reg32(dst_lo, ARM_LR, ctx);
arm_bpf_put_reg32(dst_hi, ARM_IP, ctx);
}
/* dst = dst << val */
static inline void emit_a32_lsh_i64(const s8 dst[],
const u32 val, struct jit_ctx *ctx){
const s8 *tmp = bpf2a32[TMP_REG_1];
const s8 *tmp2 = bpf2a32[TMP_REG_2];
const s8 *rd;
/* Setup operands */
rd = arm_bpf_get_reg64(dst, tmp, ctx);
/* Do LSH operation */
if (val < 32) {
emit(ARM_MOV_SI(tmp2[0], rd[0], SRTYPE_ASL, val), ctx);
emit(ARM_ORR_SI(rd[0], tmp2[0], rd[1], SRTYPE_LSR, 32 - val), ctx);
emit(ARM_MOV_SI(rd[1], rd[1], SRTYPE_ASL, val), ctx);
} else {
if (val == 32)
emit(ARM_MOV_R(rd[0], rd[1]), ctx);
else
emit(ARM_MOV_SI(rd[0], rd[1], SRTYPE_ASL, val - 32), ctx);
emit(ARM_EOR_R(rd[1], rd[1], rd[1]), ctx);
}
arm_bpf_put_reg64(dst, rd, ctx);
}
/* dst = dst >> val */
static inline void emit_a32_rsh_i64(const s8 dst[],
const u32 val, struct jit_ctx *ctx) {
const s8 *tmp = bpf2a32[TMP_REG_1];
const s8 *tmp2 = bpf2a32[TMP_REG_2];
const s8 *rd;
/* Setup operands */
rd = arm_bpf_get_reg64(dst, tmp, ctx);
/* Do LSR operation */
if (val == 0) {
/* An immediate value of 0 encodes a shift amount of 32
* for LSR. To shift by 0, don't do anything.
*/
} else if (val < 32) {
emit(ARM_MOV_SI(tmp2[1], rd[1], SRTYPE_LSR, val), ctx);
emit(ARM_ORR_SI(rd[1], tmp2[1], rd[0], SRTYPE_ASL, 32 - val), ctx);
emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_LSR, val), ctx);
} else if (val == 32) {
emit(ARM_MOV_R(rd[1], rd[0]), ctx);
emit(ARM_MOV_I(rd[0], 0), ctx);
} else {
emit(ARM_MOV_SI(rd[1], rd[0], SRTYPE_LSR, val - 32), ctx);
emit(ARM_MOV_I(rd[0], 0), ctx);
}
arm_bpf_put_reg64(dst, rd, ctx);
}
/* dst = dst >> val (signed) */
static inline void emit_a32_arsh_i64(const s8 dst[],
const u32 val, struct jit_ctx *ctx){
const s8 *tmp = bpf2a32[TMP_REG_1];
const s8 *tmp2 = bpf2a32[TMP_REG_2];
const s8 *rd;
/* Setup operands */
rd = arm_bpf_get_reg64(dst, tmp, ctx);
/* Do ARSH operation */
if (val == 0) {
/* An immediate value of 0 encodes a shift amount of 32
* for ASR. To shift by 0, don't do anything.
*/
} else if (val < 32) {
emit(ARM_MOV_SI(tmp2[1], rd[1], SRTYPE_LSR, val), ctx);
emit(ARM_ORR_SI(rd[1], tmp2[1], rd[0], SRTYPE_ASL, 32 - val), ctx);
emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_ASR, val), ctx);
} else if (val == 32) {
emit(ARM_MOV_R(rd[1], rd[0]), ctx);
emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_ASR, 31), ctx);
} else {
emit(ARM_MOV_SI(rd[1], rd[0], SRTYPE_ASR, val - 32), ctx);
emit(ARM_MOV_SI(rd[0], rd[0], SRTYPE_ASR, 31), ctx);
}
arm_bpf_put_reg64(dst, rd, ctx);
}
static inline void emit_a32_mul_r64(const s8 dst[], const s8 src[],
struct jit_ctx *ctx) {
const s8 *tmp = bpf2a32[TMP_REG_1];
const s8 *tmp2 = bpf2a32[TMP_REG_2];
const s8 *rd, *rt;
/* Setup operands for multiplication */
rd = arm_bpf_get_reg64(dst, tmp, ctx);
rt = arm_bpf_get_reg64(src, tmp2, ctx);
/* Do Multiplication */
emit(ARM_MUL(ARM_IP, rd[1], rt[0]), ctx);
emit(ARM_MUL(ARM_LR, rd[0], rt[1]), ctx);
emit(ARM_ADD_R(ARM_LR, ARM_IP, ARM_LR), ctx);
emit(ARM_UMULL(ARM_IP, rd[0], rd[1], rt[1]), ctx);
emit(ARM_ADD_R(rd[0], ARM_LR, rd[0]), ctx);
arm_bpf_put_reg32(dst_lo, ARM_IP, ctx);
arm_bpf_put_reg32(dst_hi, rd[0], ctx);
}
static bool is_ldst_imm(s16 off, const u8 size)
{
s16 off_max = 0;
switch (size) {
case BPF_B:
case BPF_W:
off_max = 0xfff;
break;
case BPF_H:
off_max = 0xff;
break;
case BPF_DW:
/* Need to make sure off+4 does not overflow. */
off_max = 0xfff - 4;
break;
}
return -off_max <= off && off <= off_max;
}
/* *(size *)(dst + off) = src */
static inline void emit_str_r(const s8 dst, const s8 src[],
s16 off, struct jit_ctx *ctx, const u8 sz){
const s8 *tmp = bpf2a32[TMP_REG_1];
s8 rd;
rd = arm_bpf_get_reg32(dst, tmp[1], ctx);
if (!is_ldst_imm(off, sz)) {
emit_a32_mov_i(tmp[0], off, ctx);
emit(ARM_ADD_R(tmp[0], tmp[0], rd), ctx);
rd = tmp[0];
off = 0;
}
switch (sz) {
case BPF_B:
/* Store a Byte */
emit(ARM_STRB_I(src_lo, rd, off), ctx);
break;
case BPF_H:
/* Store a HalfWord */
emit(ARM_STRH_I(src_lo, rd, off), ctx);
break;
case BPF_W:
/* Store a Word */
emit(ARM_STR_I(src_lo, rd, off), ctx);
break;
case BPF_DW:
/* Store a Double Word */
emit(ARM_STR_I(src_lo, rd, off), ctx);
emit(ARM_STR_I(src_hi, rd, off + 4), ctx);
break;
}
}
/* dst = *(size*)(src + off) */
static inline void emit_ldx_r(const s8 dst[], const s8 src,
s16 off, struct jit_ctx *ctx, const u8 sz){
const s8 *tmp = bpf2a32[TMP_REG_1];
const s8 *rd = is_stacked(dst_lo) ? tmp : dst;
s8 rm = src;
if (!is_ldst_imm(off, sz)) {
emit_a32_mov_i(tmp[0], off, ctx);
emit(ARM_ADD_R(tmp[0], tmp[0], src), ctx);
rm = tmp[0];
off = 0;
} else if (rd[1] == rm) {
emit(ARM_MOV_R(tmp[0], rm), ctx);
rm = tmp[0];
}
switch (sz) {
case BPF_B:
/* Load a Byte */
emit(ARM_LDRB_I(rd[1], rm, off), ctx);
if (!ctx->prog->aux->verifier_zext)
emit_a32_mov_i(rd[0], 0, ctx);
break;
case BPF_H:
/* Load a HalfWord */
emit(ARM_LDRH_I(rd[1], rm, off), ctx);
if (!ctx->prog->aux->verifier_zext)
emit_a32_mov_i(rd[0], 0, ctx);
break;
case BPF_W:
/* Load a Word */
emit(ARM_LDR_I(rd[1], rm, off), ctx);
if (!ctx->prog->aux->verifier_zext)
emit_a32_mov_i(rd[0], 0, ctx);
break;
case BPF_DW:
/* Load a Double Word */
emit(ARM_LDR_I(rd[1], rm, off), ctx);
emit(ARM_LDR_I(rd[0], rm, off + 4), ctx);
break;
}
arm_bpf_put_reg64(dst, rd, ctx);
}
/* Arithmatic Operation */
static inline void emit_ar_r(const u8 rd, const u8 rt, const u8 rm,
const u8 rn, struct jit_ctx *ctx, u8 op,
bool is_jmp64) {
switch (op) {
case BPF_JSET:
if (is_jmp64) {
emit(ARM_AND_R(ARM_IP, rt, rn), ctx);
emit(ARM_AND_R(ARM_LR, rd, rm), ctx);
emit(ARM_ORRS_R(ARM_IP, ARM_LR, ARM_IP), ctx);
} else {
emit(ARM_ANDS_R(ARM_IP, rt, rn), ctx);
}
break;
case BPF_JEQ:
case BPF_JNE:
case BPF_JGT:
case BPF_JGE:
case BPF_JLE:
case BPF_JLT:
if (is_jmp64) {
emit(ARM_CMP_R(rd, rm), ctx);
/* Only compare low halve if high halve are equal. */
_emit(ARM_COND_EQ, ARM_CMP_R(rt, rn), ctx);
} else {
emit(ARM_CMP_R(rt, rn), ctx);
}
break;
case BPF_JSLE:
case BPF_JSGT:
emit(ARM_CMP_R(rn, rt), ctx);
if (is_jmp64)
emit(ARM_SBCS_R(ARM_IP, rm, rd), ctx);
break;
case BPF_JSLT:
case BPF_JSGE:
emit(ARM_CMP_R(rt, rn), ctx);
if (is_jmp64)
emit(ARM_SBCS_R(ARM_IP, rd, rm), ctx);
break;
}
}
static int out_offset = -1; /* initialized on the first pass of build_body() */
static int emit_bpf_tail_call(struct jit_ctx *ctx)
{
/* bpf_tail_call(void *prog_ctx, struct bpf_array *array, u64 index) */
const s8 *r2 = bpf2a32[BPF_REG_2];
const s8 *r3 = bpf2a32[BPF_REG_3];
const s8 *tmp = bpf2a32[TMP_REG_1];
const s8 *tmp2 = bpf2a32[TMP_REG_2];
const s8 *tcc = bpf2a32[TCALL_CNT];
const s8 *tc;
const int idx0 = ctx->idx;
#define cur_offset (ctx->idx - idx0)
#define jmp_offset (out_offset - (cur_offset) - 2)
u32 lo, hi;
s8 r_array, r_index;
int off;
/* if (index >= array->map.max_entries)
* goto out;
*/
BUILD_BUG_ON(offsetof(struct bpf_array, map.max_entries) >
ARM_INST_LDST__IMM12);
off = offsetof(struct bpf_array, map.max_entries);
r_array = arm_bpf_get_reg32(r2[1], tmp2[0], ctx);
/* index is 32-bit for arrays */
r_index = arm_bpf_get_reg32(r3[1], tmp2[1], ctx);
/* array->map.max_entries */
emit(ARM_LDR_I(tmp[1], r_array, off), ctx);
/* index >= array->map.max_entries */
emit(ARM_CMP_R(r_index, tmp[1]), ctx);
_emit(ARM_COND_CS, ARM_B(jmp_offset), ctx);
/* tmp2[0] = array, tmp2[1] = index */
/*
* if (tail_call_cnt >= MAX_TAIL_CALL_CNT)
* goto out;
* tail_call_cnt++;
*/
lo = (u32)MAX_TAIL_CALL_CNT;
hi = (u32)((u64)MAX_TAIL_CALL_CNT >> 32);
tc = arm_bpf_get_reg64(tcc, tmp, ctx);
emit(ARM_CMP_I(tc[0], hi), ctx);
_emit(ARM_COND_EQ, ARM_CMP_I(tc[1], lo), ctx);
_emit(ARM_COND_CS, ARM_B(jmp_offset), ctx);
emit(ARM_ADDS_I(tc[1], tc[1], 1), ctx);
emit(ARM_ADC_I(tc[0], tc[0], 0), ctx);
arm_bpf_put_reg64(tcc, tmp, ctx);
/* prog = array->ptrs[index]
* if (prog == NULL)
* goto out;
*/
BUILD_BUG_ON(imm8m(offsetof(struct bpf_array, ptrs)) < 0);
off = imm8m(offsetof(struct bpf_array, ptrs));
emit(ARM_ADD_I(tmp[1], r_array, off), ctx);
emit(ARM_LDR_R_SI(tmp[1], tmp[1], r_index, SRTYPE_ASL, 2), ctx);
emit(ARM_CMP_I(tmp[1], 0), ctx);
_emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx);
/* goto *(prog->bpf_func + prologue_size); */
BUILD_BUG_ON(offsetof(struct bpf_prog, bpf_func) >
ARM_INST_LDST__IMM12);
off = offsetof(struct bpf_prog, bpf_func);
emit(ARM_LDR_I(tmp[1], tmp[1], off), ctx);
emit(ARM_ADD_I(tmp[1], tmp[1], ctx->prologue_bytes), ctx);
emit_bx_r(tmp[1], ctx);
/* 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;
#undef cur_offset
#undef jmp_offset
}
/* 0xabcd => 0xcdab */
static inline void emit_rev16(const u8 rd, const u8 rn, struct jit_ctx *ctx)
{
#if __LINUX_ARM_ARCH__ < 6
const s8 *tmp2 = bpf2a32[TMP_REG_2];
emit(ARM_AND_I(tmp2[1], rn, 0xff), ctx);
emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 8), ctx);
emit(ARM_AND_I(tmp2[0], tmp2[0], 0xff), ctx);
emit(ARM_ORR_SI(rd, tmp2[0], tmp2[1], SRTYPE_LSL, 8), ctx);
#else /* ARMv6+ */
emit(ARM_REV16(rd, rn), ctx);
#endif
}
/* 0xabcdefgh => 0xghefcdab */
static inline void emit_rev32(const u8 rd, const u8 rn, struct jit_ctx *ctx)
{
#if __LINUX_ARM_ARCH__ < 6
const s8 *tmp2 = bpf2a32[TMP_REG_2];
emit(ARM_AND_I(tmp2[1], rn, 0xff), ctx);
emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 24), ctx);
emit(ARM_ORR_SI(ARM_IP, tmp2[0], tmp2[1], SRTYPE_LSL, 24), ctx);
emit(ARM_MOV_SI(tmp2[1], rn, SRTYPE_LSR, 8), ctx);
emit(ARM_AND_I(tmp2[1], tmp2[1], 0xff), ctx);
emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 16), ctx);
emit(ARM_AND_I(tmp2[0], tmp2[0], 0xff), ctx);
emit(ARM_MOV_SI(tmp2[0], tmp2[0], SRTYPE_LSL, 8), ctx);
emit(ARM_ORR_SI(tmp2[0], tmp2[0], tmp2[1], SRTYPE_LSL, 16), ctx);
emit(ARM_ORR_R(rd, ARM_IP, tmp2[0]), ctx);
#else /* ARMv6+ */
emit(ARM_REV(rd, rn), ctx);
#endif
}
// push the scratch stack register on top of the stack
static inline void emit_push_r64(const s8 src[], struct jit_ctx *ctx)
{
const s8 *tmp2 = bpf2a32[TMP_REG_2];
const s8 *rt;
u16 reg_set = 0;
rt = arm_bpf_get_reg64(src, tmp2, ctx);
reg_set = (1 << rt[1]) | (1 << rt[0]);
emit(ARM_PUSH(reg_set), ctx);
}
static void build_prologue(struct jit_ctx *ctx)
{
const s8 arm_r0 = bpf2a32[BPF_REG_0][1];
const s8 *bpf_r1 = bpf2a32[BPF_REG_1];
const s8 *bpf_fp = bpf2a32[BPF_REG_FP];
const s8 *tcc = bpf2a32[TCALL_CNT];
/* Save callee saved registers. */
#ifdef CONFIG_FRAME_POINTER
u16 reg_set = CALLEE_PUSH_MASK | 1 << ARM_IP | 1 << ARM_PC;
emit(ARM_MOV_R(ARM_IP, ARM_SP), ctx);
emit(ARM_PUSH(reg_set), ctx);
emit(ARM_SUB_I(ARM_FP, ARM_IP, 4), ctx);
#else
emit(ARM_PUSH(CALLEE_PUSH_MASK), ctx);
emit(ARM_MOV_R(ARM_FP, ARM_SP), ctx);
#endif
/* mov r3, #0 */
/* sub r2, sp, #SCRATCH_SIZE */
emit(ARM_MOV_I(bpf_r1[0], 0), ctx);
emit(ARM_SUB_I(bpf_r1[1], ARM_SP, SCRATCH_SIZE), ctx);
ctx->stack_size = imm8m(STACK_SIZE);
/* Set up function call stack */
emit(ARM_SUB_I(ARM_SP, ARM_SP, ctx->stack_size), ctx);
/* Set up BPF prog stack base register */
emit_a32_mov_r64(true, bpf_fp, bpf_r1, ctx);
/* Initialize Tail Count */
emit(ARM_MOV_I(bpf_r1[1], 0), ctx);
emit_a32_mov_r64(true, tcc, bpf_r1, ctx);
/* Move BPF_CTX to BPF_R1 */
emit(ARM_MOV_R(bpf_r1[1], arm_r0), ctx);
/* end of prologue */
}
/* restore callee saved registers. */
static void build_epilogue(struct jit_ctx *ctx)
{
#ifdef CONFIG_FRAME_POINTER
/* When using frame pointers, some additional registers need to
* be loaded. */
u16 reg_set = CALLEE_POP_MASK | 1 << ARM_SP;
emit(ARM_SUB_I(ARM_SP, ARM_FP, hweight16(reg_set) * 4), ctx);
emit(ARM_LDM(ARM_SP, reg_set), ctx);
#else
/* Restore callee saved registers. */
emit(ARM_MOV_R(ARM_SP, ARM_FP), ctx);
emit(ARM_POP(CALLEE_POP_MASK), ctx);
#endif
}
/*
* Convert an eBPF instruction to native instruction, i.e
* JITs an eBPF instruction.
* Returns :
* 0 - Successfully JITed an 8-byte eBPF instruction
* >0 - Successfully JITed a 16-byte eBPF instruction
* <0 - Failed to JIT.
*/
static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
{
const u8 code = insn->code;
const s8 *dst = bpf2a32[insn->dst_reg];
const s8 *src = bpf2a32[insn->src_reg];
const s8 *tmp = bpf2a32[TMP_REG_1];
const s8 *tmp2 = bpf2a32[TMP_REG_2];
const s16 off = insn->off;
const s32 imm = insn->imm;
const int i = insn - ctx->prog->insnsi;
const bool is64 = BPF_CLASS(code) == BPF_ALU64;
const s8 *rd, *rs;
s8 rd_lo, rt, rm, rn;
s32 jmp_offset;
#define check_imm(bits, imm) do { \
if ((imm) >= (1 << ((bits) - 1)) || \
(imm) < -(1 << ((bits) - 1))) { \
pr_info("[%2d] imm=%d(0x%x) out of range\n", \
i, imm, imm); \
return -EINVAL; \
} \
} while (0)
#define check_imm24(imm) check_imm(24, imm)
switch (code) {
/* ALU operations */
/* dst = src */
case BPF_ALU | BPF_MOV | BPF_K:
case BPF_ALU | BPF_MOV | BPF_X:
case BPF_ALU64 | BPF_MOV | BPF_K:
case BPF_ALU64 | BPF_MOV | BPF_X:
switch (BPF_SRC(code)) {
case BPF_X:
if (imm == 1) {
/* Special mov32 for zext */
emit_a32_mov_i(dst_hi, 0, ctx);
break;
}
emit_a32_mov_r64(is64, dst, src, ctx);
break;
case BPF_K:
/* Sign-extend immediate value to destination reg */
emit_a32_mov_se_i64(is64, dst, imm, ctx);
break;
}
break;
/* dst = dst + src/imm */
/* dst = dst - src/imm */
/* dst = dst | src/imm */
/* dst = dst & src/imm */
/* dst = dst ^ src/imm */
/* dst = dst * src/imm */
/* dst = dst << src */
/* dst = dst >> src */
case BPF_ALU | BPF_ADD | BPF_K:
case BPF_ALU | BPF_ADD | BPF_X:
case BPF_ALU | BPF_SUB | BPF_K:
case BPF_ALU | BPF_SUB | BPF_X:
case BPF_ALU | BPF_OR | BPF_K:
case BPF_ALU | BPF_OR | BPF_X:
case BPF_ALU | BPF_AND | BPF_K:
case BPF_ALU | BPF_AND | BPF_X:
case BPF_ALU | BPF_XOR | BPF_K:
case BPF_ALU | BPF_XOR | BPF_X:
case BPF_ALU | BPF_MUL | BPF_K:
case BPF_ALU | BPF_MUL | BPF_X:
case BPF_ALU | BPF_LSH | BPF_X:
case BPF_ALU | BPF_RSH | BPF_X:
case BPF_ALU | BPF_ARSH | BPF_X:
case BPF_ALU64 | BPF_ADD | BPF_K:
case BPF_ALU64 | BPF_ADD | BPF_X:
case BPF_ALU64 | BPF_SUB | BPF_K:
case BPF_ALU64 | BPF_SUB | BPF_X:
case BPF_ALU64 | BPF_OR | BPF_K:
case BPF_ALU64 | BPF_OR | BPF_X:
case BPF_ALU64 | BPF_AND | BPF_K:
case BPF_ALU64 | BPF_AND | BPF_X:
case BPF_ALU64 | BPF_XOR | BPF_K:
case BPF_ALU64 | BPF_XOR | BPF_X:
switch (BPF_SRC(code)) {
case BPF_X:
emit_a32_alu_r64(is64, dst, src, ctx, BPF_OP(code));
break;
case BPF_K:
/* Move immediate value to the temporary register
* and then do the ALU operation on the temporary
* register as this will sign-extend the immediate
* value into temporary reg and then it would be
* safe to do the operation on it.
*/
emit_a32_mov_se_i64(is64, tmp2, imm, ctx);
emit_a32_alu_r64(is64, dst, tmp2, ctx, BPF_OP(code));
break;
}
break;
/* dst = dst / src(imm) */
/* dst = dst % src(imm) */
case BPF_ALU | BPF_DIV | BPF_K:
case BPF_ALU | BPF_DIV | BPF_X:
case BPF_ALU | BPF_MOD | BPF_K:
case BPF_ALU | BPF_MOD | BPF_X:
rd_lo = arm_bpf_get_reg32(dst_lo, tmp2[1], ctx);
switch (BPF_SRC(code)) {
case BPF_X:
rt = arm_bpf_get_reg32(src_lo, tmp2[0], ctx);
break;
case BPF_K:
rt = tmp2[0];
emit_a32_mov_i(rt, imm, ctx);
break;
default:
rt = src_lo;
break;
}
emit_udivmod(rd_lo, rd_lo, rt, ctx, BPF_OP(code));
arm_bpf_put_reg32(dst_lo, rd_lo, ctx);
if (!ctx->prog->aux->verifier_zext)
emit_a32_mov_i(dst_hi, 0, ctx);
break;
case BPF_ALU64 | BPF_DIV | BPF_K:
case BPF_ALU64 | BPF_DIV | BPF_X:
case BPF_ALU64 | BPF_MOD | BPF_K:
case BPF_ALU64 | BPF_MOD | BPF_X:
goto notyet;
/* dst = dst << imm */
/* dst = dst >> imm */
/* dst = dst >> imm (signed) */
case BPF_ALU | BPF_LSH | BPF_K:
case BPF_ALU | BPF_RSH | BPF_K:
case BPF_ALU | BPF_ARSH | BPF_K:
if (unlikely(imm > 31))
return -EINVAL;
if (imm)
emit_a32_alu_i(dst_lo, imm, ctx, BPF_OP(code));
if (!ctx->prog->aux->verifier_zext)
emit_a32_mov_i(dst_hi, 0, ctx);
break;
/* dst = dst << imm */
case BPF_ALU64 | BPF_LSH | BPF_K:
if (unlikely(imm > 63))
return -EINVAL;
emit_a32_lsh_i64(dst, imm, ctx);
break;
/* dst = dst >> imm */
case BPF_ALU64 | BPF_RSH | BPF_K:
if (unlikely(imm > 63))
return -EINVAL;
emit_a32_rsh_i64(dst, imm, ctx);
break;
/* dst = dst << src */
case BPF_ALU64 | BPF_LSH | BPF_X:
emit_a32_lsh_r64(dst, src, ctx);
break;
/* dst = dst >> src */
case BPF_ALU64 | BPF_RSH | BPF_X:
emit_a32_rsh_r64(dst, src, ctx);
break;
/* dst = dst >> src (signed) */
case BPF_ALU64 | BPF_ARSH | BPF_X:
emit_a32_arsh_r64(dst, src, ctx);
break;
/* dst = dst >> imm (signed) */
case BPF_ALU64 | BPF_ARSH | BPF_K:
if (unlikely(imm > 63))
return -EINVAL;
emit_a32_arsh_i64(dst, imm, ctx);
break;
/* dst = ~dst */
case BPF_ALU | BPF_NEG:
emit_a32_alu_i(dst_lo, 0, ctx, BPF_OP(code));
if (!ctx->prog->aux->verifier_zext)
emit_a32_mov_i(dst_hi, 0, ctx);
break;
/* dst = ~dst (64 bit) */
case BPF_ALU64 | BPF_NEG:
emit_a32_neg64(dst, ctx);
break;
/* dst = dst * src/imm */
case BPF_ALU64 | BPF_MUL | BPF_X:
case BPF_ALU64 | BPF_MUL | BPF_K:
switch (BPF_SRC(code)) {
case BPF_X:
emit_a32_mul_r64(dst, src, ctx);
break;
case BPF_K:
/* Move immediate value to the temporary register
* and then do the multiplication on it as this
* will sign-extend the immediate value into temp
* reg then it would be safe to do the operation
* on it.
*/
emit_a32_mov_se_i64(is64, tmp2, imm, ctx);
emit_a32_mul_r64(dst, tmp2, ctx);
break;
}
break;
/* dst = htole(dst) */
/* dst = htobe(dst) */
case BPF_ALU | BPF_END | BPF_FROM_LE:
case BPF_ALU | BPF_END | BPF_FROM_BE:
rd = arm_bpf_get_reg64(dst, tmp, ctx);
if (BPF_SRC(code) == BPF_FROM_LE)
goto emit_bswap_uxt;
switch (imm) {
case 16:
emit_rev16(rd[1], rd[1], ctx);
goto emit_bswap_uxt;
case 32:
emit_rev32(rd[1], rd[1], ctx);
goto emit_bswap_uxt;
case 64:
emit_rev32(ARM_LR, rd[1], ctx);
emit_rev32(rd[1], rd[0], ctx);
emit(ARM_MOV_R(rd[0], ARM_LR), ctx);
break;
}
goto exit;
emit_bswap_uxt:
switch (imm) {
case 16:
/* zero-extend 16 bits into 64 bits */
#if __LINUX_ARM_ARCH__ < 6
emit_a32_mov_i(tmp2[1], 0xffff, ctx);
emit(ARM_AND_R(rd[1], rd[1], tmp2[1]), ctx);
#else /* ARMv6+ */
emit(ARM_UXTH(rd[1], rd[1]), ctx);
#endif
if (!ctx->prog->aux->verifier_zext)
emit(ARM_EOR_R(rd[0], rd[0], rd[0]), ctx);
break;
case 32:
/* zero-extend 32 bits into 64 bits */
if (!ctx->prog->aux->verifier_zext)
emit(ARM_EOR_R(rd[0], rd[0], rd[0]), ctx);
break;
case 64:
/* nop */
break;
}
exit:
arm_bpf_put_reg64(dst, rd, ctx);
break;
/* dst = imm64 */
case BPF_LD | BPF_IMM | BPF_DW:
{
u64 val = (u32)imm | (u64)insn[1].imm << 32;
emit_a32_mov_i64(dst, val, ctx);
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:
rn = arm_bpf_get_reg32(src_lo, tmp2[1], ctx);
emit_ldx_r(dst, rn, off, ctx, BPF_SIZE(code));
break;
/* speculation barrier */
case BPF_ST | BPF_NOSPEC:
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:
switch (BPF_SIZE(code)) {
case BPF_DW:
/* Sign-extend immediate value into temp reg */
emit_a32_mov_se_i64(true, tmp2, imm, ctx);
break;
case BPF_W:
case BPF_H:
case BPF_B:
emit_a32_mov_i(tmp2[1], imm, ctx);
break;
}
emit_str_r(dst_lo, tmp2, off, ctx, BPF_SIZE(code));
break;
/* Atomic ops */
case BPF_STX | BPF_ATOMIC | BPF_W:
case BPF_STX | BPF_ATOMIC | BPF_DW:
goto notyet;
/* 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:
rs = arm_bpf_get_reg64(src, tmp2, ctx);
emit_str_r(dst_lo, rs, off, ctx, BPF_SIZE(code));
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 (signed) */
/* PC += off if dst >= src (signed) */
/* PC += off if dst < src (signed) */
/* PC += off if dst <= src (signed) */
/* PC += off if dst & src */
case BPF_JMP | BPF_JEQ | BPF_X:
case BPF_JMP | BPF_JGT | BPF_X:
case BPF_JMP | BPF_JGE | BPF_X:
case BPF_JMP | BPF_JNE | BPF_X:
case BPF_JMP | BPF_JSGT | BPF_X:
case BPF_JMP | BPF_JSGE | BPF_X:
case BPF_JMP | BPF_JSET | BPF_X:
case BPF_JMP | BPF_JLE | BPF_X:
case BPF_JMP | BPF_JLT | 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_JGT | BPF_X:
case BPF_JMP32 | BPF_JGE | BPF_X:
case BPF_JMP32 | BPF_JNE | BPF_X:
case BPF_JMP32 | BPF_JSGT | BPF_X:
case BPF_JMP32 | BPF_JSGE | BPF_X:
case BPF_JMP32 | BPF_JSET | BPF_X:
case BPF_JMP32 | BPF_JLE | BPF_X:
case BPF_JMP32 | BPF_JLT | BPF_X:
case BPF_JMP32 | BPF_JSLT | BPF_X:
case BPF_JMP32 | BPF_JSLE | BPF_X:
/* Setup source registers */
rm = arm_bpf_get_reg32(src_hi, tmp2[0], ctx);
rn = arm_bpf_get_reg32(src_lo, tmp2[1], ctx);
goto go_jmp;
/* 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) */
/* PC += off if dst & imm */
case BPF_JMP | BPF_JEQ | BPF_K:
case BPF_JMP | BPF_JGT | BPF_K:
case BPF_JMP | BPF_JGE | BPF_K:
case BPF_JMP | BPF_JNE | BPF_K:
case BPF_JMP | BPF_JSGT | BPF_K:
case BPF_JMP | BPF_JSGE | BPF_K:
case BPF_JMP | BPF_JSET | BPF_K:
case BPF_JMP | BPF_JLT | BPF_K:
case BPF_JMP | BPF_JLE | 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_JGT | BPF_K:
case BPF_JMP32 | BPF_JGE | BPF_K:
case BPF_JMP32 | BPF_JNE | BPF_K:
case BPF_JMP32 | BPF_JSGT | BPF_K:
case BPF_JMP32 | BPF_JSGE | BPF_K:
case BPF_JMP32 | BPF_JSET | BPF_K:
case BPF_JMP32 | BPF_JLT | BPF_K:
case BPF_JMP32 | BPF_JLE | BPF_K:
case BPF_JMP32 | BPF_JSLT | BPF_K:
case BPF_JMP32 | BPF_JSLE | BPF_K:
if (off == 0)
break;
rm = tmp2[0];
rn = tmp2[1];
/* Sign-extend immediate value */
emit_a32_mov_se_i64(true, tmp2, imm, ctx);
go_jmp:
/* Setup destination register */
rd = arm_bpf_get_reg64(dst, tmp, ctx);
/* Check for the condition */
emit_ar_r(rd[0], rd[1], rm, rn, ctx, BPF_OP(code),
BPF_CLASS(code) == BPF_JMP);
/* Setup JUMP instruction */
jmp_offset = bpf2a32_offset(i+off, i, ctx);
switch (BPF_OP(code)) {
case BPF_JNE:
case BPF_JSET:
_emit(ARM_COND_NE, ARM_B(jmp_offset), ctx);
break;
case BPF_JEQ:
_emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx);
break;
case BPF_JGT:
_emit(ARM_COND_HI, ARM_B(jmp_offset), ctx);
break;
case BPF_JGE:
_emit(ARM_COND_CS, ARM_B(jmp_offset), ctx);
break;
case BPF_JSGT:
_emit(ARM_COND_LT, ARM_B(jmp_offset), ctx);
break;
case BPF_JSGE:
_emit(ARM_COND_GE, ARM_B(jmp_offset), ctx);
break;
case BPF_JLE:
_emit(ARM_COND_LS, ARM_B(jmp_offset), ctx);
break;
case BPF_JLT:
_emit(ARM_COND_CC, ARM_B(jmp_offset), ctx);
break;
case BPF_JSLT:
_emit(ARM_COND_LT, ARM_B(jmp_offset), ctx);
break;
case BPF_JSLE:
_emit(ARM_COND_GE, ARM_B(jmp_offset), ctx);
break;
}
break;
/* JMP OFF */
case BPF_JMP | BPF_JA:
{
if (off == 0)
break;
jmp_offset = bpf2a32_offset(i+off, i, ctx);
check_imm24(jmp_offset);
emit(ARM_B(jmp_offset), ctx);
break;
}
/* tail call */
case BPF_JMP | BPF_TAIL_CALL:
if (emit_bpf_tail_call(ctx))
return -EFAULT;
break;
/* function call */
case BPF_JMP | BPF_CALL:
{
const s8 *r0 = bpf2a32[BPF_REG_0];
const s8 *r1 = bpf2a32[BPF_REG_1];
const s8 *r2 = bpf2a32[BPF_REG_2];
const s8 *r3 = bpf2a32[BPF_REG_3];
const s8 *r4 = bpf2a32[BPF_REG_4];
const s8 *r5 = bpf2a32[BPF_REG_5];
const u32 func = (u32)__bpf_call_base + (u32)imm;
emit_a32_mov_r64(true, r0, r1, ctx);
emit_a32_mov_r64(true, r1, r2, ctx);
emit_push_r64(r5, ctx);
emit_push_r64(r4, ctx);
emit_push_r64(r3, ctx);
emit_a32_mov_i(tmp[1], func, ctx);
emit_blx_r(tmp[1], ctx);
emit(ARM_ADD_I(ARM_SP, ARM_SP, imm8m(24)), ctx); // callee clean
break;
}
/* function return */
case BPF_JMP | BPF_EXIT:
/* Optimization: when last instruction is EXIT
* simply fallthrough to epilogue.
*/
if (i == ctx->prog->len - 1)
break;
jmp_offset = epilogue_offset(ctx);
check_imm24(jmp_offset);
emit(ARM_B(jmp_offset), ctx);
break;
notyet:
pr_info_once("*** NOT YET: opcode %02x ***\n", code);
return -EFAULT;
default:
pr_err_once("unknown opcode %02x\n", code);
return -EINVAL;
}
if (ctx->flags & FLAG_IMM_OVERFLOW)
/*
* this instruction generated an overflow when
* trying to access the literal pool, so
* delegate this filter to the kernel interpreter.
*/
return -1;
return 0;
}
static int build_body(struct jit_ctx *ctx)
{
const struct bpf_prog *prog = ctx->prog;
unsigned int i;
for (i = 0; i < prog->len; i++) {
const struct bpf_insn *insn = &(prog->insnsi[i]);
int ret;
ret = build_insn(insn, ctx);
/* It's used with loading the 64 bit immediate value. */
if (ret > 0) {
i++;
if (ctx->target == NULL)
ctx->offsets[i] = ctx->idx;
continue;
}
if (ctx->target == NULL)
ctx->offsets[i] = ctx->idx;
/* If unsuccesful, return with error code */
if (ret)
return ret;
}
return 0;
}
static int validate_code(struct jit_ctx *ctx)
{
int i;
for (i = 0; i < ctx->idx; i++) {
if (ctx->target[i] == __opcode_to_mem_arm(ARM_INST_UDF))
return -1;
}
return 0;
}
bool bpf_jit_needs_zext(void)
{
return true;
}
struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
{
struct bpf_prog *tmp, *orig_prog = prog;
struct bpf_binary_header *header;
bool tmp_blinded = false;
struct jit_ctx ctx;
unsigned int tmp_idx;
unsigned int image_size;
u8 *image_ptr;
/* If BPF JIT was not enabled then we must fall back to
* the interpreter.
*/
if (!prog->jit_requested)
return orig_prog;
/* If constant blinding was enabled and we failed during blinding
* then we must fall back to the interpreter. Otherwise, we save
* the new JITed code.
*/
tmp = bpf_jit_blind_constants(prog);
if (IS_ERR(tmp))
return orig_prog;
if (tmp != prog) {
tmp_blinded = true;
prog = tmp;
}
memset(&ctx, 0, sizeof(ctx));
ctx.prog = prog;
ctx.cpu_architecture = cpu_architecture();
/* Not able to allocate memory for offsets[] , then
* we must fall back to the interpreter
*/
ctx.offsets = kcalloc(prog->len, sizeof(int), GFP_KERNEL);
if (ctx.offsets == NULL) {
prog = orig_prog;
goto out;
}
/* 1) fake pass to find in the length of the JITed code,
* to compute ctx->offsets and other context variables
* needed to compute final JITed code.
* Also, calculate random starting pointer/start of JITed code
* which is prefixed by random number of fault instructions.
*
* If the first pass fails then there is no chance of it
* being successful in the second pass, so just fall back
* to the interpreter.
*/
if (build_body(&ctx)) {
prog = orig_prog;
goto out_off;
}
tmp_idx = ctx.idx;
build_prologue(&ctx);
ctx.prologue_bytes = (ctx.idx - tmp_idx) * 4;
ctx.epilogue_offset = ctx.idx;
#if __LINUX_ARM_ARCH__ < 7
tmp_idx = ctx.idx;
build_epilogue(&ctx);
ctx.epilogue_bytes = (ctx.idx - tmp_idx) * 4;
ctx.idx += ctx.imm_count;
if (ctx.imm_count) {
ctx.imms = kcalloc(ctx.imm_count, sizeof(u32), GFP_KERNEL);
if (ctx.imms == NULL) {
prog = orig_prog;
goto out_off;
}
}
#else
/* there's nothing about the epilogue on ARMv7 */
build_epilogue(&ctx);
#endif
/* Now we can get the actual image size of the JITed arm code.
* Currently, we are not considering the THUMB-2 instructions
* for jit, although it can decrease the size of the image.
*
* As each arm instruction is of length 32bit, we are translating
* number of JITed instructions into the size required to store these
* JITed code.
*/
image_size = sizeof(u32) * ctx.idx;
/* Now we know the size of the structure to make */
header = bpf_jit_binary_alloc(image_size, &image_ptr,
sizeof(u32), jit_fill_hole);
/* Not able to allocate memory for the structure then
* we must fall back to the interpretation
*/
if (header == NULL) {
prog = orig_prog;
goto out_imms;
}
/* 2.) Actual pass to generate final JIT code */
ctx.target = (u32 *) image_ptr;
ctx.idx = 0;
build_prologue(&ctx);
/* If building the body of the JITed code fails somehow,
* we fall back to the interpretation.
*/
if (build_body(&ctx) < 0) {
image_ptr = NULL;
bpf_jit_binary_free(header);
prog = orig_prog;
goto out_imms;
}
build_epilogue(&ctx);
/* 3.) Extra pass to validate JITed Code */
if (validate_code(&ctx)) {
image_ptr = NULL;
bpf_jit_binary_free(header);
prog = orig_prog;
goto out_imms;
}
flush_icache_range((u32)header, (u32)(ctx.target + ctx.idx));
if (bpf_jit_enable > 1)
/* there are 2 passes here */
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_imms:
#if __LINUX_ARM_ARCH__ < 7
if (ctx.imm_count)
kfree(ctx.imms);
#endif
out_off:
kfree(ctx.offsets);
out:
if (tmp_blinded)
bpf_jit_prog_release_other(prog, prog == orig_prog ?
tmp : orig_prog);
return prog;
}