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Code Issues Releases Wiki Activity
linux-stable/arch/riscv/net/bpf_jit_comp32.c
Tiezhu Yang ebf7f6f0a6 bpf: Change value of MAX_TAIL_CALL_CNT from 32 to 33 
In the current code, the actual max tail call count is 33 which is greater
than MAX_TAIL_CALL_CNT (defined as 32). The actual limit is not consistent
with the meaning of MAX_TAIL_CALL_CNT and thus confusing at first glance.
We can see the historical evolution from commit 04fd61ab36 ("bpf: allow
bpf programs to tail-call other bpf programs") and commit f9dabe016b
("bpf: Undo off-by-one in interpreter tail call count limit"). In order
to avoid changing existing behavior, the actual limit is 33 now, this is
reasonable.

After commit 874be05f52 ("bpf, tests: Add tail call test suite"), we can
see there exists failed testcase.

On all archs when CONFIG_BPF_JIT_ALWAYS_ON is not set:
 # echo 0 > /proc/sys/net/core/bpf_jit_enable
 # modprobe test_bpf
 # dmesg | grep -w FAIL
 Tail call error path, max count reached jited:0 ret 34 != 33 FAIL

On some archs:
 # echo 1 > /proc/sys/net/core/bpf_jit_enable
 # modprobe test_bpf
 # dmesg | grep -w FAIL
 Tail call error path, max count reached jited:1 ret 34 != 33 FAIL

Although the above failed testcase has been fixed in commit 18935a72eb
("bpf/tests: Fix error in tail call limit tests"), it would still be good
to change the value of MAX_TAIL_CALL_CNT from 32 to 33 to make the code
more readable.

The 32-bit x86 JIT was using a limit of 32, just fix the wrong comments and
limit to 33 tail calls as the constant MAX_TAIL_CALL_CNT updated. For the
mips64 JIT, use "ori" instead of "addiu" as suggested by Johan Almbladh.
For the riscv JIT, use RV_REG_TCC directly to save one register move as
suggested by Björn Töpel. For the other implementations, no function changes,
it does not change the current limit 33, the new value of MAX_TAIL_CALL_CNT
can reflect the actual max tail call count, the related tail call testcases
in test_bpf module and selftests can work well for the interpreter and the
JIT.

Here are the test results on x86_64:

 # uname -m
 x86_64
 # echo 0 > /proc/sys/net/core/bpf_jit_enable
 # modprobe test_bpf test_suite=test_tail_calls
 # dmesg | tail -1
 test_bpf: test_tail_calls: Summary: 8 PASSED, 0 FAILED, [0/8 JIT'ed]
 # rmmod test_bpf
 # echo 1 > /proc/sys/net/core/bpf_jit_enable
 # modprobe test_bpf test_suite=test_tail_calls
 # dmesg | tail -1
 test_bpf: test_tail_calls: Summary: 8 PASSED, 0 FAILED, [8/8 JIT'ed]
 # rmmod test_bpf
 # ./test_progs -t tailcalls
 #142 tailcalls:OK
 Summary: 1/11 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/bpf/1636075800-3264-1-git-send-email-yangtiezhu@loongson.cn
2021-11-16 14:03:15 +01:00

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// SPDX-License-Identifier: GPL-2.0
/*
* BPF JIT compiler for RV32G
*
* Copyright (c) 2020 Luke Nelson <luke.r.nels@gmail.com>
* Copyright (c) 2020 Xi Wang <xi.wang@gmail.com>
*
* The code is based on the BPF JIT compiler for RV64G by Björn Töpel and
* the BPF JIT compiler for 32-bit ARM by Shubham Bansal and Mircea Gherzan.
*/
#include <linux/bpf.h>
#include <linux/filter.h>
#include "bpf_jit.h"
/*
* Stack layout during BPF program execution:
*
* high
* RV32 fp => +----------+
* | saved ra |
* | saved fp | RV32 callee-saved registers
* | ... |
* +----------+ <= (fp - 4 * NR_SAVED_REGISTERS)
* | hi(R6) |
* | lo(R6) |
* | hi(R7) | JIT scratch space for BPF registers
* | lo(R7) |
* | ... |
* BPF_REG_FP => +----------+ <= (fp - 4 * NR_SAVED_REGISTERS
* | | - 4 * BPF_JIT_SCRATCH_REGS)
* | |
* | ... | BPF program stack
* | |
* RV32 sp => +----------+
* | |
* | ... | Function call stack
* | |
* +----------+
* low
*/
enum {
/* Stack layout - these are offsets from top of JIT scratch space. */
BPF_R6_HI,
BPF_R6_LO,
BPF_R7_HI,
BPF_R7_LO,
BPF_R8_HI,
BPF_R8_LO,
BPF_R9_HI,
BPF_R9_LO,
BPF_AX_HI,
BPF_AX_LO,
/* Stack space for BPF_REG_6 through BPF_REG_9 and BPF_REG_AX. */
BPF_JIT_SCRATCH_REGS,
};
/* Number of callee-saved registers stored to stack: ra, fp, s1--s7. */
#define NR_SAVED_REGISTERS 9
/* Offset from fp for BPF registers stored on stack. */
#define STACK_OFFSET(k) (-4 - (4 * NR_SAVED_REGISTERS) - (4 * (k)))
#define TMP_REG_1 (MAX_BPF_JIT_REG + 0)
#define TMP_REG_2 (MAX_BPF_JIT_REG + 1)
#define RV_REG_TCC RV_REG_T6
#define RV_REG_TCC_SAVED RV_REG_S7
static const s8 bpf2rv32[][2] = {
/* Return value from in-kernel function, and exit value from eBPF. */
[BPF_REG_0] = {RV_REG_S2, RV_REG_S1},
/* Arguments from eBPF program to in-kernel function. */
[BPF_REG_1] = {RV_REG_A1, RV_REG_A0},
[BPF_REG_2] = {RV_REG_A3, RV_REG_A2},
[BPF_REG_3] = {RV_REG_A5, RV_REG_A4},
[BPF_REG_4] = {RV_REG_A7, RV_REG_A6},
[BPF_REG_5] = {RV_REG_S4, RV_REG_S3},
/*
* Callee-saved registers that in-kernel function will preserve.
* Stored on the stack.
*/
[BPF_REG_6] = {STACK_OFFSET(BPF_R6_HI), STACK_OFFSET(BPF_R6_LO)},
[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 BPF stack. */
[BPF_REG_FP] = {RV_REG_S6, RV_REG_S5},
/* Temporary register for blinding constants. Stored on the stack. */
[BPF_REG_AX] = {STACK_OFFSET(BPF_AX_HI), STACK_OFFSET(BPF_AX_LO)},
/*
* Temporary registers used by the JIT to operate on registers stored
* on the stack. Save t0 and t1 to be used as temporaries in generated
* code.
*/
[TMP_REG_1] = {RV_REG_T3, RV_REG_T2},
[TMP_REG_2] = {RV_REG_T5, RV_REG_T4},
};
static s8 hi(const s8 *r)
{
return r[0];
}
static s8 lo(const s8 *r)
{
return r[1];
}
static void emit_imm(const s8 rd, s32 imm, struct rv_jit_context *ctx)
{
u32 upper = (imm + (1 << 11)) >> 12;
u32 lower = imm & 0xfff;
if (upper) {
emit(rv_lui(rd, upper), ctx);
emit(rv_addi(rd, rd, lower), ctx);
} else {
emit(rv_addi(rd, RV_REG_ZERO, lower), ctx);
}
}
static void emit_imm32(const s8 *rd, s32 imm, struct rv_jit_context *ctx)
{
/* Emit immediate into lower bits. */
emit_imm(lo(rd), imm, ctx);
/* Sign-extend into upper bits. */
if (imm >= 0)
emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
else
emit(rv_addi(hi(rd), RV_REG_ZERO, -1), ctx);
}
static void emit_imm64(const s8 *rd, s32 imm_hi, s32 imm_lo,
struct rv_jit_context *ctx)
{
emit_imm(lo(rd), imm_lo, ctx);
emit_imm(hi(rd), imm_hi, ctx);
}
static void __build_epilogue(bool is_tail_call, struct rv_jit_context *ctx)
{
int stack_adjust = ctx->stack_size;
const s8 *r0 = bpf2rv32[BPF_REG_0];
/* Set return value if not tail call. */
if (!is_tail_call) {
emit(rv_addi(RV_REG_A0, lo(r0), 0), ctx);
emit(rv_addi(RV_REG_A1, hi(r0), 0), ctx);
}
/* Restore callee-saved registers. */
emit(rv_lw(RV_REG_RA, stack_adjust - 4, RV_REG_SP), ctx);
emit(rv_lw(RV_REG_FP, stack_adjust - 8, RV_REG_SP), ctx);
emit(rv_lw(RV_REG_S1, stack_adjust - 12, RV_REG_SP), ctx);
emit(rv_lw(RV_REG_S2, stack_adjust - 16, RV_REG_SP), ctx);
emit(rv_lw(RV_REG_S3, stack_adjust - 20, RV_REG_SP), ctx);
emit(rv_lw(RV_REG_S4, stack_adjust - 24, RV_REG_SP), ctx);
emit(rv_lw(RV_REG_S5, stack_adjust - 28, RV_REG_SP), ctx);
emit(rv_lw(RV_REG_S6, stack_adjust - 32, RV_REG_SP), ctx);
emit(rv_lw(RV_REG_S7, stack_adjust - 36, RV_REG_SP), ctx);
emit(rv_addi(RV_REG_SP, RV_REG_SP, stack_adjust), ctx);
if (is_tail_call) {
/*
* goto *(t0 + 4);
* Skips first instruction of prologue which initializes tail
* call counter. Assumes t0 contains address of target program,
* see emit_bpf_tail_call.
*/
emit(rv_jalr(RV_REG_ZERO, RV_REG_T0, 4), ctx);
} else {
emit(rv_jalr(RV_REG_ZERO, RV_REG_RA, 0), ctx);
}
}
static bool is_stacked(s8 reg)
{
return reg < 0;
}
static const s8 *bpf_get_reg64(const s8 *reg, const s8 *tmp,
struct rv_jit_context *ctx)
{
if (is_stacked(hi(reg))) {
emit(rv_lw(hi(tmp), hi(reg), RV_REG_FP), ctx);
emit(rv_lw(lo(tmp), lo(reg), RV_REG_FP), ctx);
reg = tmp;
}
return reg;
}
static void bpf_put_reg64(const s8 *reg, const s8 *src,
struct rv_jit_context *ctx)
{
if (is_stacked(hi(reg))) {
emit(rv_sw(RV_REG_FP, hi(reg), hi(src)), ctx);
emit(rv_sw(RV_REG_FP, lo(reg), lo(src)), ctx);
}
}
static const s8 *bpf_get_reg32(const s8 *reg, const s8 *tmp,
struct rv_jit_context *ctx)
{
if (is_stacked(lo(reg))) {
emit(rv_lw(lo(tmp), lo(reg), RV_REG_FP), ctx);
reg = tmp;
}
return reg;
}
static void bpf_put_reg32(const s8 *reg, const s8 *src,
struct rv_jit_context *ctx)
{
if (is_stacked(lo(reg))) {
emit(rv_sw(RV_REG_FP, lo(reg), lo(src)), ctx);
if (!ctx->prog->aux->verifier_zext)
emit(rv_sw(RV_REG_FP, hi(reg), RV_REG_ZERO), ctx);
} else if (!ctx->prog->aux->verifier_zext) {
emit(rv_addi(hi(reg), RV_REG_ZERO, 0), ctx);
}
}
static void emit_jump_and_link(u8 rd, s32 rvoff, bool force_jalr,
struct rv_jit_context *ctx)
{
s32 upper, lower;
if (rvoff && is_21b_int(rvoff) && !force_jalr) {
emit(rv_jal(rd, rvoff >> 1), ctx);
return;
}
upper = (rvoff + (1 << 11)) >> 12;
lower = rvoff & 0xfff;
emit(rv_auipc(RV_REG_T1, upper), ctx);
emit(rv_jalr(rd, RV_REG_T1, lower), ctx);
}
static void emit_alu_i64(const s8 *dst, s32 imm,
struct rv_jit_context *ctx, const u8 op)
{
const s8 *tmp1 = bpf2rv32[TMP_REG_1];
const s8 *rd = bpf_get_reg64(dst, tmp1, ctx);
switch (op) {
case BPF_MOV:
emit_imm32(rd, imm, ctx);
break;
case BPF_AND:
if (is_12b_int(imm)) {
emit(rv_andi(lo(rd), lo(rd), imm), ctx);
} else {
emit_imm(RV_REG_T0, imm, ctx);
emit(rv_and(lo(rd), lo(rd), RV_REG_T0), ctx);
}
if (imm >= 0)
emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
break;
case BPF_OR:
if (is_12b_int(imm)) {
emit(rv_ori(lo(rd), lo(rd), imm), ctx);
} else {
emit_imm(RV_REG_T0, imm, ctx);
emit(rv_or(lo(rd), lo(rd), RV_REG_T0), ctx);
}
if (imm < 0)
emit(rv_ori(hi(rd), RV_REG_ZERO, -1), ctx);
break;
case BPF_XOR:
if (is_12b_int(imm)) {
emit(rv_xori(lo(rd), lo(rd), imm), ctx);
} else {
emit_imm(RV_REG_T0, imm, ctx);
emit(rv_xor(lo(rd), lo(rd), RV_REG_T0), ctx);
}
if (imm < 0)
emit(rv_xori(hi(rd), hi(rd), -1), ctx);
break;
case BPF_LSH:
if (imm >= 32) {
emit(rv_slli(hi(rd), lo(rd), imm - 32), ctx);
emit(rv_addi(lo(rd), RV_REG_ZERO, 0), ctx);
} else if (imm == 0) {
/* Do nothing. */
} else {
emit(rv_srli(RV_REG_T0, lo(rd), 32 - imm), ctx);
emit(rv_slli(hi(rd), hi(rd), imm), ctx);
emit(rv_or(hi(rd), RV_REG_T0, hi(rd)), ctx);
emit(rv_slli(lo(rd), lo(rd), imm), ctx);
}
break;
case BPF_RSH:
if (imm >= 32) {
emit(rv_srli(lo(rd), hi(rd), imm - 32), ctx);
emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
} else if (imm == 0) {
/* Do nothing. */
} else {
emit(rv_slli(RV_REG_T0, hi(rd), 32 - imm), ctx);
emit(rv_srli(lo(rd), lo(rd), imm), ctx);
emit(rv_or(lo(rd), RV_REG_T0, lo(rd)), ctx);
emit(rv_srli(hi(rd), hi(rd), imm), ctx);
}
break;
case BPF_ARSH:
if (imm >= 32) {
emit(rv_srai(lo(rd), hi(rd), imm - 32), ctx);
emit(rv_srai(hi(rd), hi(rd), 31), ctx);
} else if (imm == 0) {
/* Do nothing. */
} else {
emit(rv_slli(RV_REG_T0, hi(rd), 32 - imm), ctx);
emit(rv_srli(lo(rd), lo(rd), imm), ctx);
emit(rv_or(lo(rd), RV_REG_T0, lo(rd)), ctx);
emit(rv_srai(hi(rd), hi(rd), imm), ctx);
}
break;
}
bpf_put_reg64(dst, rd, ctx);
}
static void emit_alu_i32(const s8 *dst, s32 imm,
struct rv_jit_context *ctx, const u8 op)
{
const s8 *tmp1 = bpf2rv32[TMP_REG_1];
const s8 *rd = bpf_get_reg32(dst, tmp1, ctx);
switch (op) {
case BPF_MOV:
emit_imm(lo(rd), imm, ctx);
break;
case BPF_ADD:
if (is_12b_int(imm)) {
emit(rv_addi(lo(rd), lo(rd), imm), ctx);
} else {
emit_imm(RV_REG_T0, imm, ctx);
emit(rv_add(lo(rd), lo(rd), RV_REG_T0), ctx);
}
break;
case BPF_SUB:
if (is_12b_int(-imm)) {
emit(rv_addi(lo(rd), lo(rd), -imm), ctx);
} else {
emit_imm(RV_REG_T0, imm, ctx);
emit(rv_sub(lo(rd), lo(rd), RV_REG_T0), ctx);
}
break;
case BPF_AND:
if (is_12b_int(imm)) {
emit(rv_andi(lo(rd), lo(rd), imm), ctx);
} else {
emit_imm(RV_REG_T0, imm, ctx);
emit(rv_and(lo(rd), lo(rd), RV_REG_T0), ctx);
}
break;
case BPF_OR:
if (is_12b_int(imm)) {
emit(rv_ori(lo(rd), lo(rd), imm), ctx);
} else {
emit_imm(RV_REG_T0, imm, ctx);
emit(rv_or(lo(rd), lo(rd), RV_REG_T0), ctx);
}
break;
case BPF_XOR:
if (is_12b_int(imm)) {
emit(rv_xori(lo(rd), lo(rd), imm), ctx);
} else {
emit_imm(RV_REG_T0, imm, ctx);
emit(rv_xor(lo(rd), lo(rd), RV_REG_T0), ctx);
}
break;
case BPF_LSH:
if (is_12b_int(imm)) {
emit(rv_slli(lo(rd), lo(rd), imm), ctx);
} else {
emit_imm(RV_REG_T0, imm, ctx);
emit(rv_sll(lo(rd), lo(rd), RV_REG_T0), ctx);
}
break;
case BPF_RSH:
if (is_12b_int(imm)) {
emit(rv_srli(lo(rd), lo(rd), imm), ctx);
} else {
emit_imm(RV_REG_T0, imm, ctx);
emit(rv_srl(lo(rd), lo(rd), RV_REG_T0), ctx);
}
break;
case BPF_ARSH:
if (is_12b_int(imm)) {
emit(rv_srai(lo(rd), lo(rd), imm), ctx);
} else {
emit_imm(RV_REG_T0, imm, ctx);
emit(rv_sra(lo(rd), lo(rd), RV_REG_T0), ctx);
}
break;
}
bpf_put_reg32(dst, rd, ctx);
}
static void emit_alu_r64(const s8 *dst, const s8 *src,
struct rv_jit_context *ctx, const u8 op)
{
const s8 *tmp1 = bpf2rv32[TMP_REG_1];
const s8 *tmp2 = bpf2rv32[TMP_REG_2];
const s8 *rd = bpf_get_reg64(dst, tmp1, ctx);
const s8 *rs = bpf_get_reg64(src, tmp2, ctx);
switch (op) {
case BPF_MOV:
emit(rv_addi(lo(rd), lo(rs), 0), ctx);
emit(rv_addi(hi(rd), hi(rs), 0), ctx);
break;
case BPF_ADD:
if (rd == rs) {
emit(rv_srli(RV_REG_T0, lo(rd), 31), ctx);
emit(rv_slli(hi(rd), hi(rd), 1), ctx);
emit(rv_or(hi(rd), RV_REG_T0, hi(rd)), ctx);
emit(rv_slli(lo(rd), lo(rd), 1), ctx);
} else {
emit(rv_add(lo(rd), lo(rd), lo(rs)), ctx);
emit(rv_sltu(RV_REG_T0, lo(rd), lo(rs)), ctx);
emit(rv_add(hi(rd), hi(rd), hi(rs)), ctx);
emit(rv_add(hi(rd), hi(rd), RV_REG_T0), ctx);
}
break;
case BPF_SUB:
emit(rv_sub(RV_REG_T1, hi(rd), hi(rs)), ctx);
emit(rv_sltu(RV_REG_T0, lo(rd), lo(rs)), ctx);
emit(rv_sub(hi(rd), RV_REG_T1, RV_REG_T0), ctx);
emit(rv_sub(lo(rd), lo(rd), lo(rs)), ctx);
break;
case BPF_AND:
emit(rv_and(lo(rd), lo(rd), lo(rs)), ctx);
emit(rv_and(hi(rd), hi(rd), hi(rs)), ctx);
break;
case BPF_OR:
emit(rv_or(lo(rd), lo(rd), lo(rs)), ctx);
emit(rv_or(hi(rd), hi(rd), hi(rs)), ctx);
break;
case BPF_XOR:
emit(rv_xor(lo(rd), lo(rd), lo(rs)), ctx);
emit(rv_xor(hi(rd), hi(rd), hi(rs)), ctx);
break;
case BPF_MUL:
emit(rv_mul(RV_REG_T0, hi(rs), lo(rd)), ctx);
emit(rv_mul(hi(rd), hi(rd), lo(rs)), ctx);
emit(rv_mulhu(RV_REG_T1, lo(rd), lo(rs)), ctx);
emit(rv_add(hi(rd), hi(rd), RV_REG_T0), ctx);
emit(rv_mul(lo(rd), lo(rd), lo(rs)), ctx);
emit(rv_add(hi(rd), hi(rd), RV_REG_T1), ctx);
break;
case BPF_LSH:
emit(rv_addi(RV_REG_T0, lo(rs), -32), ctx);
emit(rv_blt(RV_REG_T0, RV_REG_ZERO, 8), ctx);
emit(rv_sll(hi(rd), lo(rd), RV_REG_T0), ctx);
emit(rv_addi(lo(rd), RV_REG_ZERO, 0), ctx);
emit(rv_jal(RV_REG_ZERO, 16), ctx);
emit(rv_addi(RV_REG_T1, RV_REG_ZERO, 31), ctx);
emit(rv_srli(RV_REG_T0, lo(rd), 1), ctx);
emit(rv_sub(RV_REG_T1, RV_REG_T1, lo(rs)), ctx);
emit(rv_srl(RV_REG_T0, RV_REG_T0, RV_REG_T1), ctx);
emit(rv_sll(hi(rd), hi(rd), lo(rs)), ctx);
emit(rv_or(hi(rd), RV_REG_T0, hi(rd)), ctx);
emit(rv_sll(lo(rd), lo(rd), lo(rs)), ctx);
break;
case BPF_RSH:
emit(rv_addi(RV_REG_T0, lo(rs), -32), ctx);
emit(rv_blt(RV_REG_T0, RV_REG_ZERO, 8), ctx);
emit(rv_srl(lo(rd), hi(rd), RV_REG_T0), ctx);
emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
emit(rv_jal(RV_REG_ZERO, 16), ctx);
emit(rv_addi(RV_REG_T1, RV_REG_ZERO, 31), ctx);
emit(rv_slli(RV_REG_T0, hi(rd), 1), ctx);
emit(rv_sub(RV_REG_T1, RV_REG_T1, lo(rs)), ctx);
emit(rv_sll(RV_REG_T0, RV_REG_T0, RV_REG_T1), ctx);
emit(rv_srl(lo(rd), lo(rd), lo(rs)), ctx);
emit(rv_or(lo(rd), RV_REG_T0, lo(rd)), ctx);
emit(rv_srl(hi(rd), hi(rd), lo(rs)), ctx);
break;
case BPF_ARSH:
emit(rv_addi(RV_REG_T0, lo(rs), -32), ctx);
emit(rv_blt(RV_REG_T0, RV_REG_ZERO, 8), ctx);
emit(rv_sra(lo(rd), hi(rd), RV_REG_T0), ctx);
emit(rv_srai(hi(rd), hi(rd), 31), ctx);
emit(rv_jal(RV_REG_ZERO, 16), ctx);
emit(rv_addi(RV_REG_T1, RV_REG_ZERO, 31), ctx);
emit(rv_slli(RV_REG_T0, hi(rd), 1), ctx);
emit(rv_sub(RV_REG_T1, RV_REG_T1, lo(rs)), ctx);
emit(rv_sll(RV_REG_T0, RV_REG_T0, RV_REG_T1), ctx);
emit(rv_srl(lo(rd), lo(rd), lo(rs)), ctx);
emit(rv_or(lo(rd), RV_REG_T0, lo(rd)), ctx);
emit(rv_sra(hi(rd), hi(rd), lo(rs)), ctx);
break;
case BPF_NEG:
emit(rv_sub(lo(rd), RV_REG_ZERO, lo(rd)), ctx);
emit(rv_sltu(RV_REG_T0, RV_REG_ZERO, lo(rd)), ctx);
emit(rv_sub(hi(rd), RV_REG_ZERO, hi(rd)), ctx);
emit(rv_sub(hi(rd), hi(rd), RV_REG_T0), ctx);
break;
}
bpf_put_reg64(dst, rd, ctx);
}
static void emit_alu_r32(const s8 *dst, const s8 *src,
struct rv_jit_context *ctx, const u8 op)
{
const s8 *tmp1 = bpf2rv32[TMP_REG_1];
const s8 *tmp2 = bpf2rv32[TMP_REG_2];
const s8 *rd = bpf_get_reg32(dst, tmp1, ctx);
const s8 *rs = bpf_get_reg32(src, tmp2, ctx);
switch (op) {
case BPF_MOV:
emit(rv_addi(lo(rd), lo(rs), 0), ctx);
break;
case BPF_ADD:
emit(rv_add(lo(rd), lo(rd), lo(rs)), ctx);
break;
case BPF_SUB:
emit(rv_sub(lo(rd), lo(rd), lo(rs)), ctx);
break;
case BPF_AND:
emit(rv_and(lo(rd), lo(rd), lo(rs)), ctx);
break;
case BPF_OR:
emit(rv_or(lo(rd), lo(rd), lo(rs)), ctx);
break;
case BPF_XOR:
emit(rv_xor(lo(rd), lo(rd), lo(rs)), ctx);
break;
case BPF_MUL:
emit(rv_mul(lo(rd), lo(rd), lo(rs)), ctx);
break;
case BPF_DIV:
emit(rv_divu(lo(rd), lo(rd), lo(rs)), ctx);
break;
case BPF_MOD:
emit(rv_remu(lo(rd), lo(rd), lo(rs)), ctx);
break;
case BPF_LSH:
emit(rv_sll(lo(rd), lo(rd), lo(rs)), ctx);
break;
case BPF_RSH:
emit(rv_srl(lo(rd), lo(rd), lo(rs)), ctx);
break;
case BPF_ARSH:
emit(rv_sra(lo(rd), lo(rd), lo(rs)), ctx);
break;
case BPF_NEG:
emit(rv_sub(lo(rd), RV_REG_ZERO, lo(rd)), ctx);
break;
}
bpf_put_reg32(dst, rd, ctx);
}
static int emit_branch_r64(const s8 *src1, const s8 *src2, s32 rvoff,
struct rv_jit_context *ctx, const u8 op)
{
int e, s = ctx->ninsns;
const s8 *tmp1 = bpf2rv32[TMP_REG_1];
const s8 *tmp2 = bpf2rv32[TMP_REG_2];
const s8 *rs1 = bpf_get_reg64(src1, tmp1, ctx);
const s8 *rs2 = bpf_get_reg64(src2, tmp2, ctx);
/*
* NO_JUMP skips over the rest of the instructions and the
* emit_jump_and_link, meaning the BPF branch is not taken.
* JUMP skips directly to the emit_jump_and_link, meaning
* the BPF branch is taken.
*
* The fallthrough case results in the BPF branch being taken.
*/
#define NO_JUMP(idx) (6 + (2 * (idx)))
#define JUMP(idx) (2 + (2 * (idx)))
switch (op) {
case BPF_JEQ:
emit(rv_bne(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
emit(rv_bne(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
break;
case BPF_JGT:
emit(rv_bgtu(hi(rs1), hi(rs2), JUMP(2)), ctx);
emit(rv_bltu(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
emit(rv_bleu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
break;
case BPF_JLT:
emit(rv_bltu(hi(rs1), hi(rs2), JUMP(2)), ctx);
emit(rv_bgtu(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
emit(rv_bgeu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
break;
case BPF_JGE:
emit(rv_bgtu(hi(rs1), hi(rs2), JUMP(2)), ctx);
emit(rv_bltu(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
emit(rv_bltu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
break;
case BPF_JLE:
emit(rv_bltu(hi(rs1), hi(rs2), JUMP(2)), ctx);
emit(rv_bgtu(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
emit(rv_bgtu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
break;
case BPF_JNE:
emit(rv_bne(hi(rs1), hi(rs2), JUMP(1)), ctx);
emit(rv_beq(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
break;
case BPF_JSGT:
emit(rv_bgt(hi(rs1), hi(rs2), JUMP(2)), ctx);
emit(rv_blt(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
emit(rv_bleu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
break;
case BPF_JSLT:
emit(rv_blt(hi(rs1), hi(rs2), JUMP(2)), ctx);
emit(rv_bgt(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
emit(rv_bgeu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
break;
case BPF_JSGE:
emit(rv_bgt(hi(rs1), hi(rs2), JUMP(2)), ctx);
emit(rv_blt(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
emit(rv_bltu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
break;
case BPF_JSLE:
emit(rv_blt(hi(rs1), hi(rs2), JUMP(2)), ctx);
emit(rv_bgt(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
emit(rv_bgtu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
break;
case BPF_JSET:
emit(rv_and(RV_REG_T0, hi(rs1), hi(rs2)), ctx);
emit(rv_bne(RV_REG_T0, RV_REG_ZERO, JUMP(2)), ctx);
emit(rv_and(RV_REG_T0, lo(rs1), lo(rs2)), ctx);
emit(rv_beq(RV_REG_T0, RV_REG_ZERO, NO_JUMP(0)), ctx);
break;
}
#undef NO_JUMP
#undef JUMP
e = ctx->ninsns;
/* Adjust for extra insns. */
rvoff -= ninsns_rvoff(e - s);
emit_jump_and_link(RV_REG_ZERO, rvoff, true, ctx);
return 0;
}
static int emit_bcc(u8 op, u8 rd, u8 rs, int rvoff, struct rv_jit_context *ctx)
{
int e, s = ctx->ninsns;
bool far = false;
int off;
if (op == BPF_JSET) {
/*
* BPF_JSET is a special case: it has no inverse so we always
* treat it as a far branch.
*/
far = true;
} else if (!is_13b_int(rvoff)) {
op = invert_bpf_cond(op);
far = true;
}
/*
* For a far branch, the condition is negated and we jump over the
* branch itself, and the two instructions from emit_jump_and_link.
* For a near branch, just use rvoff.
*/
off = far ? 6 : (rvoff >> 1);
switch (op) {
case BPF_JEQ:
emit(rv_beq(rd, rs, off), ctx);
break;
case BPF_JGT:
emit(rv_bgtu(rd, rs, off), ctx);
break;
case BPF_JLT:
emit(rv_bltu(rd, rs, off), ctx);
break;
case BPF_JGE:
emit(rv_bgeu(rd, rs, off), ctx);
break;
case BPF_JLE:
emit(rv_bleu(rd, rs, off), ctx);
break;
case BPF_JNE:
emit(rv_bne(rd, rs, off), ctx);
break;
case BPF_JSGT:
emit(rv_bgt(rd, rs, off), ctx);
break;
case BPF_JSLT:
emit(rv_blt(rd, rs, off), ctx);
break;
case BPF_JSGE:
emit(rv_bge(rd, rs, off), ctx);
break;
case BPF_JSLE:
emit(rv_ble(rd, rs, off), ctx);
break;
case BPF_JSET:
emit(rv_and(RV_REG_T0, rd, rs), ctx);
emit(rv_beq(RV_REG_T0, RV_REG_ZERO, off), ctx);
break;
}
if (far) {
e = ctx->ninsns;
/* Adjust for extra insns. */
rvoff -= ninsns_rvoff(e - s);
emit_jump_and_link(RV_REG_ZERO, rvoff, true, ctx);
}
return 0;
}
static int emit_branch_r32(const s8 *src1, const s8 *src2, s32 rvoff,
struct rv_jit_context *ctx, const u8 op)
{
int e, s = ctx->ninsns;
const s8 *tmp1 = bpf2rv32[TMP_REG_1];
const s8 *tmp2 = bpf2rv32[TMP_REG_2];
const s8 *rs1 = bpf_get_reg32(src1, tmp1, ctx);
const s8 *rs2 = bpf_get_reg32(src2, tmp2, ctx);
e = ctx->ninsns;
/* Adjust for extra insns. */
rvoff -= ninsns_rvoff(e - s);
if (emit_bcc(op, lo(rs1), lo(rs2), rvoff, ctx))
return -1;
return 0;
}
static void emit_call(bool fixed, u64 addr, struct rv_jit_context *ctx)
{
const s8 *r0 = bpf2rv32[BPF_REG_0];
const s8 *r5 = bpf2rv32[BPF_REG_5];
u32 upper = ((u32)addr + (1 << 11)) >> 12;
u32 lower = addr & 0xfff;
/* R1-R4 already in correct registers---need to push R5 to stack. */
emit(rv_addi(RV_REG_SP, RV_REG_SP, -16), ctx);
emit(rv_sw(RV_REG_SP, 0, lo(r5)), ctx);
emit(rv_sw(RV_REG_SP, 4, hi(r5)), ctx);
/* Backup TCC. */
emit(rv_addi(RV_REG_TCC_SAVED, RV_REG_TCC, 0), ctx);
/*
* Use lui/jalr pair to jump to absolute address. Don't use emit_imm as
* the number of emitted instructions should not depend on the value of
* addr.
*/
emit(rv_lui(RV_REG_T1, upper), ctx);
emit(rv_jalr(RV_REG_RA, RV_REG_T1, lower), ctx);
/* Restore TCC. */
emit(rv_addi(RV_REG_TCC, RV_REG_TCC_SAVED, 0), ctx);
/* Set return value and restore stack. */
emit(rv_addi(lo(r0), RV_REG_A0, 0), ctx);
emit(rv_addi(hi(r0), RV_REG_A1, 0), ctx);
emit(rv_addi(RV_REG_SP, RV_REG_SP, 16), ctx);
}
static int emit_bpf_tail_call(int insn, struct rv_jit_context *ctx)
{
/*
* R1 -> &ctx
* R2 -> &array
* R3 -> index
*/
int tc_ninsn, off, start_insn = ctx->ninsns;
const s8 *arr_reg = bpf2rv32[BPF_REG_2];
const s8 *idx_reg = bpf2rv32[BPF_REG_3];
tc_ninsn = insn ? ctx->offset[insn] - ctx->offset[insn - 1] :
ctx->offset[0];
/* max_entries = array->map.max_entries; */
off = offsetof(struct bpf_array, map.max_entries);
if (is_12b_check(off, insn))
return -1;
emit(rv_lw(RV_REG_T1, off, lo(arr_reg)), ctx);
/*
* if (index >= max_entries)
* goto out;
*/
off = ninsns_rvoff(tc_ninsn - (ctx->ninsns - start_insn));
emit_bcc(BPF_JGE, lo(idx_reg), RV_REG_T1, off, ctx);
/*
* if (--tcc < 0)
* goto out;
*/
emit(rv_addi(RV_REG_TCC, RV_REG_TCC, -1), ctx);
off = ninsns_rvoff(tc_ninsn - (ctx->ninsns - start_insn));
emit_bcc(BPF_JSLT, RV_REG_TCC, RV_REG_ZERO, off, ctx);
/*
* prog = array->ptrs[index];
* if (!prog)
* goto out;
*/
emit(rv_slli(RV_REG_T0, lo(idx_reg), 2), ctx);
emit(rv_add(RV_REG_T0, RV_REG_T0, lo(arr_reg)), ctx);
off = offsetof(struct bpf_array, ptrs);
if (is_12b_check(off, insn))
return -1;
emit(rv_lw(RV_REG_T0, off, RV_REG_T0), ctx);
off = ninsns_rvoff(tc_ninsn - (ctx->ninsns - start_insn));
emit_bcc(BPF_JEQ, RV_REG_T0, RV_REG_ZERO, off, ctx);
/*
* tcc = temp_tcc;
* goto *(prog->bpf_func + 4);
*/
off = offsetof(struct bpf_prog, bpf_func);
if (is_12b_check(off, insn))
return -1;
emit(rv_lw(RV_REG_T0, off, RV_REG_T0), ctx);
/* Epilogue jumps to *(t0 + 4). */
__build_epilogue(true, ctx);
return 0;
}
static int emit_load_r64(const s8 *dst, const s8 *src, s16 off,
struct rv_jit_context *ctx, const u8 size)
{
const s8 *tmp1 = bpf2rv32[TMP_REG_1];
const s8 *tmp2 = bpf2rv32[TMP_REG_2];
const s8 *rd = bpf_get_reg64(dst, tmp1, ctx);
const s8 *rs = bpf_get_reg64(src, tmp2, ctx);
emit_imm(RV_REG_T0, off, ctx);
emit(rv_add(RV_REG_T0, RV_REG_T0, lo(rs)), ctx);
switch (size) {
case BPF_B:
emit(rv_lbu(lo(rd), 0, RV_REG_T0), ctx);
if (!ctx->prog->aux->verifier_zext)
emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
break;
case BPF_H:
emit(rv_lhu(lo(rd), 0, RV_REG_T0), ctx);
if (!ctx->prog->aux->verifier_zext)
emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
break;
case BPF_W:
emit(rv_lw(lo(rd), 0, RV_REG_T0), ctx);
if (!ctx->prog->aux->verifier_zext)
emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
break;
case BPF_DW:
emit(rv_lw(lo(rd), 0, RV_REG_T0), ctx);
emit(rv_lw(hi(rd), 4, RV_REG_T0), ctx);
break;
}
bpf_put_reg64(dst, rd, ctx);
return 0;
}
static int emit_store_r64(const s8 *dst, const s8 *src, s16 off,
struct rv_jit_context *ctx, const u8 size,
const u8 mode)
{
const s8 *tmp1 = bpf2rv32[TMP_REG_1];
const s8 *tmp2 = bpf2rv32[TMP_REG_2];
const s8 *rd = bpf_get_reg64(dst, tmp1, ctx);
const s8 *rs = bpf_get_reg64(src, tmp2, ctx);
if (mode == BPF_ATOMIC && size != BPF_W)
return -1;
emit_imm(RV_REG_T0, off, ctx);
emit(rv_add(RV_REG_T0, RV_REG_T0, lo(rd)), ctx);
switch (size) {
case BPF_B:
emit(rv_sb(RV_REG_T0, 0, lo(rs)), ctx);
break;
case BPF_H:
emit(rv_sh(RV_REG_T0, 0, lo(rs)), ctx);
break;
case BPF_W:
switch (mode) {
case BPF_MEM:
emit(rv_sw(RV_REG_T0, 0, lo(rs)), ctx);
break;
case BPF_ATOMIC: /* Only BPF_ADD supported */
emit(rv_amoadd_w(RV_REG_ZERO, lo(rs), RV_REG_T0, 0, 0),
ctx);
break;
}
break;
case BPF_DW:
emit(rv_sw(RV_REG_T0, 0, lo(rs)), ctx);
emit(rv_sw(RV_REG_T0, 4, hi(rs)), ctx);
break;
}
return 0;
}
static void emit_rev16(const s8 rd, struct rv_jit_context *ctx)
{
emit(rv_slli(rd, rd, 16), ctx);
emit(rv_slli(RV_REG_T1, rd, 8), ctx);
emit(rv_srli(rd, rd, 8), ctx);
emit(rv_add(RV_REG_T1, rd, RV_REG_T1), ctx);
emit(rv_srli(rd, RV_REG_T1, 16), ctx);
}
static void emit_rev32(const s8 rd, struct rv_jit_context *ctx)
{
emit(rv_addi(RV_REG_T1, RV_REG_ZERO, 0), ctx);
emit(rv_andi(RV_REG_T0, rd, 255), ctx);
emit(rv_add(RV_REG_T1, RV_REG_T1, RV_REG_T0), ctx);
emit(rv_slli(RV_REG_T1, RV_REG_T1, 8), ctx);
emit(rv_srli(rd, rd, 8), ctx);
emit(rv_andi(RV_REG_T0, rd, 255), ctx);
emit(rv_add(RV_REG_T1, RV_REG_T1, RV_REG_T0), ctx);
emit(rv_slli(RV_REG_T1, RV_REG_T1, 8), ctx);
emit(rv_srli(rd, rd, 8), ctx);
emit(rv_andi(RV_REG_T0, rd, 255), ctx);
emit(rv_add(RV_REG_T1, RV_REG_T1, RV_REG_T0), ctx);
emit(rv_slli(RV_REG_T1, RV_REG_T1, 8), ctx);
emit(rv_srli(rd, rd, 8), ctx);
emit(rv_andi(RV_REG_T0, rd, 255), ctx);
emit(rv_add(RV_REG_T1, RV_REG_T1, RV_REG_T0), ctx);
emit(rv_addi(rd, RV_REG_T1, 0), ctx);
}
static void emit_zext64(const s8 *dst, struct rv_jit_context *ctx)
{
const s8 *rd;
const s8 *tmp1 = bpf2rv32[TMP_REG_1];
rd = bpf_get_reg64(dst, tmp1, ctx);
emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
bpf_put_reg64(dst, rd, ctx);
}
int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
bool extra_pass)
{
bool is64 = BPF_CLASS(insn->code) == BPF_ALU64 ||
BPF_CLASS(insn->code) == BPF_JMP;
int s, e, rvoff, i = insn - ctx->prog->insnsi;
u8 code = insn->code;
s16 off = insn->off;
s32 imm = insn->imm;
const s8 *dst = bpf2rv32[insn->dst_reg];
const s8 *src = bpf2rv32[insn->src_reg];
const s8 *tmp1 = bpf2rv32[TMP_REG_1];
const s8 *tmp2 = bpf2rv32[TMP_REG_2];
switch (code) {
case BPF_ALU64 | BPF_MOV | BPF_X:
case BPF_ALU64 | BPF_ADD | BPF_X:
case BPF_ALU64 | BPF_ADD | BPF_K:
case BPF_ALU64 | BPF_SUB | BPF_X:
case BPF_ALU64 | BPF_SUB | BPF_K:
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_MUL | BPF_X:
case BPF_ALU64 | BPF_MUL | BPF_K:
case BPF_ALU64 | BPF_LSH | BPF_X:
case BPF_ALU64 | BPF_RSH | BPF_X:
case BPF_ALU64 | BPF_ARSH | BPF_X:
if (BPF_SRC(code) == BPF_K) {
emit_imm32(tmp2, imm, ctx);
src = tmp2;
}
emit_alu_r64(dst, src, ctx, BPF_OP(code));
break;
case BPF_ALU64 | BPF_NEG:
emit_alu_r64(dst, tmp2, ctx, BPF_OP(code));
break;
case BPF_ALU64 | BPF_DIV | BPF_X:
case BPF_ALU64 | BPF_DIV | BPF_K:
case BPF_ALU64 | BPF_MOD | BPF_X:
case BPF_ALU64 | BPF_MOD | BPF_K:
goto notsupported;
case BPF_ALU64 | BPF_MOV | BPF_K:
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:
emit_alu_i64(dst, imm, ctx, BPF_OP(code));
break;
case BPF_ALU | BPF_MOV | BPF_X:
if (imm == 1) {
/* Special mov32 for zext. */
emit_zext64(dst, ctx);
break;
}
fallthrough;
case BPF_ALU | BPF_ADD | BPF_X:
case BPF_ALU | BPF_SUB | BPF_X:
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_MUL | BPF_X:
case BPF_ALU | BPF_MUL | BPF_K:
case BPF_ALU | BPF_DIV | BPF_X:
case BPF_ALU | BPF_DIV | BPF_K:
case BPF_ALU | BPF_MOD | BPF_X:
case BPF_ALU | BPF_MOD | BPF_K:
case BPF_ALU | BPF_LSH | BPF_X:
case BPF_ALU | BPF_RSH | BPF_X:
case BPF_ALU | BPF_ARSH | BPF_X:
if (BPF_SRC(code) == BPF_K) {
emit_imm32(tmp2, imm, ctx);
src = tmp2;
}
emit_alu_r32(dst, src, ctx, BPF_OP(code));
break;
case BPF_ALU | BPF_MOV | BPF_K:
case BPF_ALU | BPF_ADD | BPF_K:
case BPF_ALU | BPF_SUB | BPF_K:
case BPF_ALU | BPF_AND | BPF_K:
case BPF_ALU | BPF_OR | BPF_K:
case BPF_ALU | BPF_XOR | BPF_K:
case BPF_ALU | BPF_LSH | BPF_K:
case BPF_ALU | BPF_RSH | BPF_K:
case BPF_ALU | BPF_ARSH | BPF_K:
/*
* mul,div,mod are handled in the BPF_X case since there are
* no RISC-V I-type equivalents.
*/
emit_alu_i32(dst, imm, ctx, BPF_OP(code));
break;
case BPF_ALU | BPF_NEG:
/*
* src is ignored---choose tmp2 as a dummy register since it
* is not on the stack.
*/
emit_alu_r32(dst, tmp2, ctx, BPF_OP(code));
break;
case BPF_ALU | BPF_END | BPF_FROM_LE:
{
const s8 *rd = bpf_get_reg64(dst, tmp1, ctx);
switch (imm) {
case 16:
emit(rv_slli(lo(rd), lo(rd), 16), ctx);
emit(rv_srli(lo(rd), lo(rd), 16), ctx);
fallthrough;
case 32:
if (!ctx->prog->aux->verifier_zext)
emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
break;
case 64:
/* Do nothing. */
break;
default:
pr_err("bpf-jit: BPF_END imm %d invalid\n", imm);
return -1;
}
bpf_put_reg64(dst, rd, ctx);
break;
}
case BPF_ALU | BPF_END | BPF_FROM_BE:
{
const s8 *rd = bpf_get_reg64(dst, tmp1, ctx);
switch (imm) {
case 16:
emit_rev16(lo(rd), ctx);
if (!ctx->prog->aux->verifier_zext)
emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
break;
case 32:
emit_rev32(lo(rd), ctx);
if (!ctx->prog->aux->verifier_zext)
emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
break;
case 64:
/* Swap upper and lower halves. */
emit(rv_addi(RV_REG_T0, lo(rd), 0), ctx);
emit(rv_addi(lo(rd), hi(rd), 0), ctx);
emit(rv_addi(hi(rd), RV_REG_T0, 0), ctx);
/* Swap each half. */
emit_rev32(lo(rd), ctx);
emit_rev32(hi(rd), ctx);
break;
default:
pr_err("bpf-jit: BPF_END imm %d invalid\n", imm);
return -1;
}
bpf_put_reg64(dst, rd, ctx);
break;
}
case BPF_JMP | BPF_JA:
rvoff = rv_offset(i, off, ctx);
emit_jump_and_link(RV_REG_ZERO, rvoff, false, ctx);
break;
case BPF_JMP | BPF_CALL:
{
bool fixed;
int ret;
u64 addr;
ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass, &addr,
&fixed);
if (ret < 0)
return ret;
emit_call(fixed, addr, ctx);
break;
}
case BPF_JMP | BPF_TAIL_CALL:
if (emit_bpf_tail_call(i, ctx))
return -1;
break;
case BPF_JMP | BPF_JEQ | BPF_X:
case BPF_JMP | BPF_JEQ | BPF_K:
case BPF_JMP32 | BPF_JEQ | BPF_X:
case BPF_JMP32 | BPF_JEQ | BPF_K:
case BPF_JMP | BPF_JNE | BPF_X:
case BPF_JMP | BPF_JNE | BPF_K:
case BPF_JMP32 | BPF_JNE | BPF_X:
case BPF_JMP32 | BPF_JNE | BPF_K:
case BPF_JMP | BPF_JLE | BPF_X:
case BPF_JMP | BPF_JLE | BPF_K:
case BPF_JMP32 | BPF_JLE | BPF_X:
case BPF_JMP32 | BPF_JLE | BPF_K:
case BPF_JMP | BPF_JLT | BPF_X:
case BPF_JMP | BPF_JLT | BPF_K:
case BPF_JMP32 | BPF_JLT | BPF_X:
case BPF_JMP32 | BPF_JLT | BPF_K:
case BPF_JMP | BPF_JGE | BPF_X:
case BPF_JMP | BPF_JGE | BPF_K:
case BPF_JMP32 | BPF_JGE | BPF_X:
case BPF_JMP32 | BPF_JGE | BPF_K:
case BPF_JMP | BPF_JGT | BPF_X:
case BPF_JMP | BPF_JGT | BPF_K:
case BPF_JMP32 | BPF_JGT | BPF_X:
case BPF_JMP32 | BPF_JGT | BPF_K:
case BPF_JMP | BPF_JSLE | BPF_X:
case BPF_JMP | BPF_JSLE | BPF_K:
case BPF_JMP32 | BPF_JSLE | BPF_X:
case BPF_JMP32 | BPF_JSLE | BPF_K:
case BPF_JMP | BPF_JSLT | BPF_X:
case BPF_JMP | BPF_JSLT | BPF_K:
case BPF_JMP32 | BPF_JSLT | BPF_X:
case BPF_JMP32 | BPF_JSLT | BPF_K:
case BPF_JMP | BPF_JSGE | BPF_X:
case BPF_JMP | BPF_JSGE | BPF_K:
case BPF_JMP32 | BPF_JSGE | BPF_X:
case BPF_JMP32 | BPF_JSGE | BPF_K:
case BPF_JMP | BPF_JSGT | BPF_X:
case BPF_JMP | BPF_JSGT | BPF_K:
case BPF_JMP32 | BPF_JSGT | BPF_X:
case BPF_JMP32 | BPF_JSGT | BPF_K:
case BPF_JMP | BPF_JSET | BPF_X:
case BPF_JMP | BPF_JSET | BPF_K:
case BPF_JMP32 | BPF_JSET | BPF_X:
case BPF_JMP32 | BPF_JSET | BPF_K:
rvoff = rv_offset(i, off, ctx);
if (BPF_SRC(code) == BPF_K) {
s = ctx->ninsns;
emit_imm32(tmp2, imm, ctx);
src = tmp2;
e = ctx->ninsns;
rvoff -= ninsns_rvoff(e - s);
}
if (is64)
emit_branch_r64(dst, src, rvoff, ctx, BPF_OP(code));
else
emit_branch_r32(dst, src, rvoff, ctx, BPF_OP(code));
break;
case BPF_JMP | BPF_EXIT:
if (i == ctx->prog->len - 1)
break;
rvoff = epilogue_offset(ctx);
emit_jump_and_link(RV_REG_ZERO, rvoff, false, ctx);
break;
case BPF_LD | BPF_IMM | BPF_DW:
{
struct bpf_insn insn1 = insn[1];
s32 imm_lo = imm;
s32 imm_hi = insn1.imm;
const s8 *rd = bpf_get_reg64(dst, tmp1, ctx);
emit_imm64(rd, imm_hi, imm_lo, ctx);
bpf_put_reg64(dst, rd, ctx);
return 1;
}
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:
if (emit_load_r64(dst, src, off, ctx, BPF_SIZE(code)))
return -1;
break;
/* speculation barrier */
case BPF_ST | BPF_NOSPEC:
break;
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:
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:
if (BPF_CLASS(code) == BPF_ST) {
emit_imm32(tmp2, imm, ctx);
src = tmp2;
}
if (emit_store_r64(dst, src, off, ctx, BPF_SIZE(code),
BPF_MODE(code)))
return -1;
break;
case BPF_STX | BPF_ATOMIC | BPF_W:
if (insn->imm != BPF_ADD) {
pr_info_once(
"bpf-jit: not supported: atomic operation %02x ***\n",
insn->imm);
return -EFAULT;
}
if (emit_store_r64(dst, src, off, ctx, BPF_SIZE(code),
BPF_MODE(code)))
return -1;
break;
/* No hardware support for 8-byte atomics in RV32. */
case BPF_STX | BPF_ATOMIC | BPF_DW:
/* Fallthrough. */
notsupported:
pr_info_once("bpf-jit: not supported: opcode %02x ***\n", code);
return -EFAULT;
default:
pr_err("bpf-jit: unknown opcode %02x\n", code);
return -EINVAL;
}
return 0;
}
void bpf_jit_build_prologue(struct rv_jit_context *ctx)
{
const s8 *fp = bpf2rv32[BPF_REG_FP];
const s8 *r1 = bpf2rv32[BPF_REG_1];
int stack_adjust = 0;
int bpf_stack_adjust =
round_up(ctx->prog->aux->stack_depth, STACK_ALIGN);
/* Make space for callee-saved registers. */
stack_adjust += NR_SAVED_REGISTERS * sizeof(u32);
/* Make space for BPF registers on stack. */
stack_adjust += BPF_JIT_SCRATCH_REGS * sizeof(u32);
/* Make space for BPF stack. */
stack_adjust += bpf_stack_adjust;
/* Round up for stack alignment. */
stack_adjust = round_up(stack_adjust, STACK_ALIGN);
/*
* The first instruction sets the tail-call-counter (TCC) register.
* This instruction is skipped by tail calls.
*/
emit(rv_addi(RV_REG_TCC, RV_REG_ZERO, MAX_TAIL_CALL_CNT), ctx);
emit(rv_addi(RV_REG_SP, RV_REG_SP, -stack_adjust), ctx);
/* Save callee-save registers. */
emit(rv_sw(RV_REG_SP, stack_adjust - 4, RV_REG_RA), ctx);
emit(rv_sw(RV_REG_SP, stack_adjust - 8, RV_REG_FP), ctx);
emit(rv_sw(RV_REG_SP, stack_adjust - 12, RV_REG_S1), ctx);
emit(rv_sw(RV_REG_SP, stack_adjust - 16, RV_REG_S2), ctx);
emit(rv_sw(RV_REG_SP, stack_adjust - 20, RV_REG_S3), ctx);
emit(rv_sw(RV_REG_SP, stack_adjust - 24, RV_REG_S4), ctx);
emit(rv_sw(RV_REG_SP, stack_adjust - 28, RV_REG_S5), ctx);
emit(rv_sw(RV_REG_SP, stack_adjust - 32, RV_REG_S6), ctx);
emit(rv_sw(RV_REG_SP, stack_adjust - 36, RV_REG_S7), ctx);
/* Set fp: used as the base address for stacked BPF registers. */
emit(rv_addi(RV_REG_FP, RV_REG_SP, stack_adjust), ctx);
/* Set up BPF frame pointer. */
emit(rv_addi(lo(fp), RV_REG_SP, bpf_stack_adjust), ctx);
emit(rv_addi(hi(fp), RV_REG_ZERO, 0), ctx);
/* Set up BPF context pointer. */
emit(rv_addi(lo(r1), RV_REG_A0, 0), ctx);
emit(rv_addi(hi(r1), RV_REG_ZERO, 0), ctx);
ctx->stack_size = stack_adjust;
}
void bpf_jit_build_epilogue(struct rv_jit_context *ctx)
{
__build_epilogue(false, ctx);
}
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