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linux/arch/riscv/net/bpf_jit_comp64.c
Andrea Parri e59db0623f riscv, bpf: Make BPF_CMPXCHG fully ordered 
According to the prototype formal BPF memory consistency model
discussed e.g. in [1] and following the ordering properties of
the C/in-kernel macro atomic_cmpxchg(), a BPF atomic operation
with the BPF_CMPXCHG modifier is fully ordered.  However, the
current RISC-V JIT lowerings fail to meet such memory ordering
property.  This is illustrated by the following litmus test:

BPF BPF__MP+success_cmpxchg+fence
{
 0:r1=x; 0:r3=y; 0:r5=1;
 1:r2=y; 1:r4=f; 1:r7=x;
}
 P0                               | P1                                         ;
 *(u64 *)(r1 + 0) = 1             | r1 = *(u64 *)(r2 + 0)                      ;
 r2 = cmpxchg_64 (r3 + 0, r4, r5) | r3 = atomic_fetch_add((u64 *)(r4 + 0), r5) ;
                                  | r6 = *(u64 *)(r7 + 0)                      ;
exists (1:r1=1 /\ 1:r6=0)

whose "exists" clause is not satisfiable according to the BPF
memory model.  Using the current RISC-V JIT lowerings, the test
can be mapped to the following RISC-V litmus test:

RISCV RISCV__MP+success_cmpxchg+fence
{
 0:x1=x; 0:x3=y; 0:x5=1;
 1:x2=y; 1:x4=f; 1:x7=x;
}
 P0                 | P1                          ;
 sd x5, 0(x1)       | ld x1, 0(x2)                ;
 L00:               | amoadd.d.aqrl x3, x5, 0(x4) ;
 lr.d x2, 0(x3)     | ld x6, 0(x7)                ;
 bne x2, x4, L01    |                             ;
 sc.d x6, x5, 0(x3) |                             ;
 bne x6, x4, L00    |                             ;
 fence rw, rw       |                             ;
 L01:               |                             ;
exists (1:x1=1 /\ 1:x6=0)

where the two stores in P0 can be reordered.  Update the RISC-V
JIT lowerings/implementation of BPF_CMPXCHG to emit an SC with
RELEASE ("rl") annotation in order to meet the expected memory
ordering guarantees.  The resulting RISC-V JIT lowerings of
BPF_CMPXCHG match the RISC-V lowerings of the C atomic_cmpxchg().

Other lowerings were fixed via 20a759df3b ("riscv, bpf: make
some atomic operations fully ordered").

Fixes: dd642ccb45 ("riscv, bpf: Implement more atomic operations for RV64")
Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lpc.events/event/18/contributions/1949/attachments/1665/3441/bpfmemmodel.2024.09.19p.pdf [1]
Link: https://lore.kernel.org/bpf/20241017143628.2673894-1-parri.andrea@gmail.com
2024-10-17 17:14:48 +02:00

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// SPDX-License-Identifier: GPL-2.0
/* BPF JIT compiler for RV64G
*
* Copyright(c) 2019 Björn Töpel <bjorn.topel@gmail.com>
*
*/
#include <linux/bitfield.h>
#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/memory.h>
#include <linux/stop_machine.h>
#include <asm/patch.h>
#include <asm/cfi.h>
#include <asm/percpu.h>
#include "bpf_jit.h"
#define RV_MAX_REG_ARGS 8
#define RV_FENTRY_NINSNS 2
#define RV_FENTRY_NBYTES (RV_FENTRY_NINSNS * 4)
#define RV_KCFI_NINSNS (IS_ENABLED(CONFIG_CFI_CLANG) ? 1 : 0)
/* imm that allows emit_imm to emit max count insns */
#define RV_MAX_COUNT_IMM 0x7FFF7FF7FF7FF7FF
#define RV_REG_TCC RV_REG_A6
#define RV_REG_TCC_SAVED RV_REG_S6 /* Store A6 in S6 if program do calls */
#define RV_REG_ARENA RV_REG_S7 /* For storing arena_vm_start */
static const int regmap[] = {
[BPF_REG_0] = RV_REG_A5,
[BPF_REG_1] = RV_REG_A0,
[BPF_REG_2] = RV_REG_A1,
[BPF_REG_3] = RV_REG_A2,
[BPF_REG_4] = RV_REG_A3,
[BPF_REG_5] = RV_REG_A4,
[BPF_REG_6] = RV_REG_S1,
[BPF_REG_7] = RV_REG_S2,
[BPF_REG_8] = RV_REG_S3,
[BPF_REG_9] = RV_REG_S4,
[BPF_REG_FP] = RV_REG_S5,
[BPF_REG_AX] = RV_REG_T0,
};
static const int pt_regmap[] = {
[RV_REG_A0] = offsetof(struct pt_regs, a0),
[RV_REG_A1] = offsetof(struct pt_regs, a1),
[RV_REG_A2] = offsetof(struct pt_regs, a2),
[RV_REG_A3] = offsetof(struct pt_regs, a3),
[RV_REG_A4] = offsetof(struct pt_regs, a4),
[RV_REG_A5] = offsetof(struct pt_regs, a5),
[RV_REG_S1] = offsetof(struct pt_regs, s1),
[RV_REG_S2] = offsetof(struct pt_regs, s2),
[RV_REG_S3] = offsetof(struct pt_regs, s3),
[RV_REG_S4] = offsetof(struct pt_regs, s4),
[RV_REG_S5] = offsetof(struct pt_regs, s5),
[RV_REG_T0] = offsetof(struct pt_regs, t0),
};
enum {
RV_CTX_F_SEEN_TAIL_CALL = 0,
RV_CTX_F_SEEN_CALL = RV_REG_RA,
RV_CTX_F_SEEN_S1 = RV_REG_S1,
RV_CTX_F_SEEN_S2 = RV_REG_S2,
RV_CTX_F_SEEN_S3 = RV_REG_S3,
RV_CTX_F_SEEN_S4 = RV_REG_S4,
RV_CTX_F_SEEN_S5 = RV_REG_S5,
RV_CTX_F_SEEN_S6 = RV_REG_S6,
};
static u8 bpf_to_rv_reg(int bpf_reg, struct rv_jit_context *ctx)
{
u8 reg = regmap[bpf_reg];
switch (reg) {
case RV_CTX_F_SEEN_S1:
case RV_CTX_F_SEEN_S2:
case RV_CTX_F_SEEN_S3:
case RV_CTX_F_SEEN_S4:
case RV_CTX_F_SEEN_S5:
case RV_CTX_F_SEEN_S6:
__set_bit(reg, &ctx->flags);
}
return reg;
};
static bool seen_reg(int reg, struct rv_jit_context *ctx)
{
switch (reg) {
case RV_CTX_F_SEEN_CALL:
case RV_CTX_F_SEEN_S1:
case RV_CTX_F_SEEN_S2:
case RV_CTX_F_SEEN_S3:
case RV_CTX_F_SEEN_S4:
case RV_CTX_F_SEEN_S5:
case RV_CTX_F_SEEN_S6:
return test_bit(reg, &ctx->flags);
}
return false;
}
static void mark_fp(struct rv_jit_context *ctx)
{
__set_bit(RV_CTX_F_SEEN_S5, &ctx->flags);
}
static void mark_call(struct rv_jit_context *ctx)
{
__set_bit(RV_CTX_F_SEEN_CALL, &ctx->flags);
}
static bool seen_call(struct rv_jit_context *ctx)
{
return test_bit(RV_CTX_F_SEEN_CALL, &ctx->flags);
}
static void mark_tail_call(struct rv_jit_context *ctx)
{
__set_bit(RV_CTX_F_SEEN_TAIL_CALL, &ctx->flags);
}
static bool seen_tail_call(struct rv_jit_context *ctx)
{
return test_bit(RV_CTX_F_SEEN_TAIL_CALL, &ctx->flags);
}
static u8 rv_tail_call_reg(struct rv_jit_context *ctx)
{
mark_tail_call(ctx);
if (seen_call(ctx)) {
__set_bit(RV_CTX_F_SEEN_S6, &ctx->flags);
return RV_REG_S6;
}
return RV_REG_A6;
}
static bool is_32b_int(s64 val)
{
return -(1L << 31) <= val && val < (1L << 31);
}
static bool in_auipc_jalr_range(s64 val)
{
/*
* auipc+jalr can reach any signed PC-relative offset in the range
* [-2^31 - 2^11, 2^31 - 2^11).
*/
return (-(1L << 31) - (1L << 11)) <= val &&
val < ((1L << 31) - (1L << 11));
}
/* Modify rd pointer to alternate reg to avoid corrupting original reg */
static void emit_sextw_alt(u8 *rd, u8 ra, struct rv_jit_context *ctx)
{
emit_sextw(ra, *rd, ctx);
*rd = ra;
}
static void emit_zextw_alt(u8 *rd, u8 ra, struct rv_jit_context *ctx)
{
emit_zextw(ra, *rd, ctx);
*rd = ra;
}
/* Emit fixed-length instructions for address */
static int emit_addr(u8 rd, u64 addr, bool extra_pass, struct rv_jit_context *ctx)
{
/*
* Use the ro_insns(RX) to calculate the offset as the BPF program will
* finally run from this memory region.
*/
u64 ip = (u64)(ctx->ro_insns + ctx->ninsns);
s64 off = addr - ip;
s64 upper = (off + (1 << 11)) >> 12;
s64 lower = off & 0xfff;
if (extra_pass && !in_auipc_jalr_range(off)) {
pr_err("bpf-jit: target offset 0x%llx is out of range\n", off);
return -ERANGE;
}
emit(rv_auipc(rd, upper), ctx);
emit(rv_addi(rd, rd, lower), ctx);
return 0;
}
/* Emit variable-length instructions for 32-bit and 64-bit imm */
static void emit_imm(u8 rd, s64 val, struct rv_jit_context *ctx)
{
/* Note that the immediate from the add is sign-extended,
* which means that we need to compensate this by adding 2^12,
* when the 12th bit is set. A simpler way of doing this, and
* getting rid of the check, is to just add 2**11 before the
* shift. The "Loading a 32-Bit constant" example from the
* "Computer Organization and Design, RISC-V edition" book by
* Patterson/Hennessy highlights this fact.
*
* This also means that we need to process LSB to MSB.
*/
s64 upper = (val + (1 << 11)) >> 12;
/* Sign-extend lower 12 bits to 64 bits since immediates for li, addiw,
* and addi are signed and RVC checks will perform signed comparisons.
*/
s64 lower = ((val & 0xfff) << 52) >> 52;
int shift;
if (is_32b_int(val)) {
if (upper)
emit_lui(rd, upper, ctx);
if (!upper) {
emit_li(rd, lower, ctx);
return;
}
emit_addiw(rd, rd, lower, ctx);
return;
}
shift = __ffs(upper);
upper >>= shift;
shift += 12;
emit_imm(rd, upper, ctx);
emit_slli(rd, rd, shift, ctx);
if (lower)
emit_addi(rd, rd, lower, ctx);
}
static void __build_epilogue(bool is_tail_call, struct rv_jit_context *ctx)
{
int stack_adjust = ctx->stack_size, store_offset = stack_adjust - 8;
if (seen_reg(RV_REG_RA, ctx)) {
emit_ld(RV_REG_RA, store_offset, RV_REG_SP, ctx);
store_offset -= 8;
}
emit_ld(RV_REG_FP, store_offset, RV_REG_SP, ctx);
store_offset -= 8;
if (seen_reg(RV_REG_S1, ctx)) {
emit_ld(RV_REG_S1, store_offset, RV_REG_SP, ctx);
store_offset -= 8;
}
if (seen_reg(RV_REG_S2, ctx)) {
emit_ld(RV_REG_S2, store_offset, RV_REG_SP, ctx);
store_offset -= 8;
}
if (seen_reg(RV_REG_S3, ctx)) {
emit_ld(RV_REG_S3, store_offset, RV_REG_SP, ctx);
store_offset -= 8;
}
if (seen_reg(RV_REG_S4, ctx)) {
emit_ld(RV_REG_S4, store_offset, RV_REG_SP, ctx);
store_offset -= 8;
}
if (seen_reg(RV_REG_S5, ctx)) {
emit_ld(RV_REG_S5, store_offset, RV_REG_SP, ctx);
store_offset -= 8;
}
if (seen_reg(RV_REG_S6, ctx)) {
emit_ld(RV_REG_S6, store_offset, RV_REG_SP, ctx);
store_offset -= 8;
}
if (ctx->arena_vm_start) {
emit_ld(RV_REG_ARENA, store_offset, RV_REG_SP, ctx);
store_offset -= 8;
}
emit_addi(RV_REG_SP, RV_REG_SP, stack_adjust, ctx);
/* Set return value. */
if (!is_tail_call)
emit_addiw(RV_REG_A0, RV_REG_A5, 0, ctx);
emit_jalr(RV_REG_ZERO, is_tail_call ? RV_REG_T3 : RV_REG_RA,
/* kcfi, fentry and TCC init insns will be skipped on tailcall */
is_tail_call ? (RV_KCFI_NINSNS + RV_FENTRY_NINSNS + 1) * 4 : 0,
ctx);
}
static void emit_bcc(u8 cond, u8 rd, u8 rs, int rvoff,
struct rv_jit_context *ctx)
{
switch (cond) {
case BPF_JEQ:
emit(rv_beq(rd, rs, rvoff >> 1), ctx);
return;
case BPF_JGT:
emit(rv_bltu(rs, rd, rvoff >> 1), ctx);
return;
case BPF_JLT:
emit(rv_bltu(rd, rs, rvoff >> 1), ctx);
return;
case BPF_JGE:
emit(rv_bgeu(rd, rs, rvoff >> 1), ctx);
return;
case BPF_JLE:
emit(rv_bgeu(rs, rd, rvoff >> 1), ctx);
return;
case BPF_JNE:
emit(rv_bne(rd, rs, rvoff >> 1), ctx);
return;
case BPF_JSGT:
emit(rv_blt(rs, rd, rvoff >> 1), ctx);
return;
case BPF_JSLT:
emit(rv_blt(rd, rs, rvoff >> 1), ctx);
return;
case BPF_JSGE:
emit(rv_bge(rd, rs, rvoff >> 1), ctx);
return;
case BPF_JSLE:
emit(rv_bge(rs, rd, rvoff >> 1), ctx);
}
}
static void emit_branch(u8 cond, u8 rd, u8 rs, int rvoff,
struct rv_jit_context *ctx)
{
s64 upper, lower;
if (is_13b_int(rvoff)) {
emit_bcc(cond, rd, rs, rvoff, ctx);
return;
}
/* Adjust for jal */
rvoff -= 4;
/* Transform, e.g.:
* bne rd,rs,foo
* to
* beq rd,rs,<.L1>
* (auipc foo)
* jal(r) foo
* .L1
*/
cond = invert_bpf_cond(cond);
if (is_21b_int(rvoff)) {
emit_bcc(cond, rd, rs, 8, ctx);
emit(rv_jal(RV_REG_ZERO, rvoff >> 1), ctx);
return;
}
/* 32b No need for an additional rvoff adjustment, since we
* get that from the auipc at PC', where PC = PC' + 4.
*/
upper = (rvoff + (1 << 11)) >> 12;
lower = rvoff & 0xfff;
emit_bcc(cond, rd, rs, 12, ctx);
emit(rv_auipc(RV_REG_T1, upper), ctx);
emit(rv_jalr(RV_REG_ZERO, RV_REG_T1, lower), ctx);
}
static int emit_bpf_tail_call(int insn, struct rv_jit_context *ctx)
{
int tc_ninsn, off, start_insn = ctx->ninsns;
u8 tcc = rv_tail_call_reg(ctx);
/* a0: &ctx
* a1: &array
* a2: index
*
* if (index >= array->map.max_entries)
* goto out;
*/
tc_ninsn = insn ? ctx->offset[insn] - ctx->offset[insn - 1] :
ctx->offset[0];
emit_zextw(RV_REG_A2, RV_REG_A2, ctx);
off = offsetof(struct bpf_array, map.max_entries);
if (is_12b_check(off, insn))
return -1;
emit(rv_lwu(RV_REG_T1, off, RV_REG_A1), ctx);
off = ninsns_rvoff(tc_ninsn - (ctx->ninsns - start_insn));
emit_branch(BPF_JGE, RV_REG_A2, RV_REG_T1, off, ctx);
/* if (--TCC < 0)
* goto out;
*/
emit_addi(RV_REG_TCC, tcc, -1, ctx);
off = ninsns_rvoff(tc_ninsn - (ctx->ninsns - start_insn));
emit_branch(BPF_JSLT, RV_REG_TCC, RV_REG_ZERO, off, ctx);
/* prog = array->ptrs[index];
* if (!prog)
* goto out;
*/
emit_sh3add(RV_REG_T2, RV_REG_A2, RV_REG_A1, ctx);
off = offsetof(struct bpf_array, ptrs);
if (is_12b_check(off, insn))
return -1;
emit_ld(RV_REG_T2, off, RV_REG_T2, ctx);
off = ninsns_rvoff(tc_ninsn - (ctx->ninsns - start_insn));
emit_branch(BPF_JEQ, RV_REG_T2, RV_REG_ZERO, off, ctx);
/* goto *(prog->bpf_func + 4); */
off = offsetof(struct bpf_prog, bpf_func);
if (is_12b_check(off, insn))
return -1;
emit_ld(RV_REG_T3, off, RV_REG_T2, ctx);
__build_epilogue(true, ctx);
return 0;
}
static void init_regs(u8 *rd, u8 *rs, const struct bpf_insn *insn,
struct rv_jit_context *ctx)
{
u8 code = insn->code;
switch (code) {
case BPF_JMP | BPF_JA:
case BPF_JMP | BPF_CALL:
case BPF_JMP | BPF_EXIT:
case BPF_JMP | BPF_TAIL_CALL:
break;
default:
*rd = bpf_to_rv_reg(insn->dst_reg, ctx);
}
if (code & (BPF_ALU | BPF_X) || code & (BPF_ALU64 | BPF_X) ||
code & (BPF_JMP | BPF_X) || code & (BPF_JMP32 | BPF_X) ||
code & BPF_LDX || code & BPF_STX)
*rs = bpf_to_rv_reg(insn->src_reg, ctx);
}
static int emit_jump_and_link(u8 rd, s64 rvoff, bool fixed_addr,
struct rv_jit_context *ctx)
{
s64 upper, lower;
if (rvoff && fixed_addr && is_21b_int(rvoff)) {
emit(rv_jal(rd, rvoff >> 1), ctx);
return 0;
} else if (in_auipc_jalr_range(rvoff)) {
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);
return 0;
}
pr_err("bpf-jit: target offset 0x%llx is out of range\n", rvoff);
return -ERANGE;
}
static bool is_signed_bpf_cond(u8 cond)
{
return cond == BPF_JSGT || cond == BPF_JSLT ||
cond == BPF_JSGE || cond == BPF_JSLE;
}
static int emit_call(u64 addr, bool fixed_addr, struct rv_jit_context *ctx)
{
s64 off = 0;
u64 ip;
if (addr && ctx->insns && ctx->ro_insns) {
/*
* Use the ro_insns(RX) to calculate the offset as the BPF
* program will finally run from this memory region.
*/
ip = (u64)(long)(ctx->ro_insns + ctx->ninsns);
off = addr - ip;
}
return emit_jump_and_link(RV_REG_RA, off, fixed_addr, ctx);
}
static inline void emit_kcfi(u32 hash, struct rv_jit_context *ctx)
{
if (IS_ENABLED(CONFIG_CFI_CLANG))
emit(hash, ctx);
}
static void emit_atomic(u8 rd, u8 rs, s16 off, s32 imm, bool is64,
struct rv_jit_context *ctx)
{
u8 r0;
int jmp_offset;
if (off) {
if (is_12b_int(off)) {
emit_addi(RV_REG_T1, rd, off, ctx);
} else {
emit_imm(RV_REG_T1, off, ctx);
emit_add(RV_REG_T1, RV_REG_T1, rd, ctx);
}
rd = RV_REG_T1;
}
switch (imm) {
/* lock *(u32/u64 *)(dst_reg + off16) <op>= src_reg */
case BPF_ADD:
emit(is64 ? rv_amoadd_d(RV_REG_ZERO, rs, rd, 0, 0) :
rv_amoadd_w(RV_REG_ZERO, rs, rd, 0, 0), ctx);
break;
case BPF_AND:
emit(is64 ? rv_amoand_d(RV_REG_ZERO, rs, rd, 0, 0) :
rv_amoand_w(RV_REG_ZERO, rs, rd, 0, 0), ctx);
break;
case BPF_OR:
emit(is64 ? rv_amoor_d(RV_REG_ZERO, rs, rd, 0, 0) :
rv_amoor_w(RV_REG_ZERO, rs, rd, 0, 0), ctx);
break;
case BPF_XOR:
emit(is64 ? rv_amoxor_d(RV_REG_ZERO, rs, rd, 0, 0) :
rv_amoxor_w(RV_REG_ZERO, rs, rd, 0, 0), ctx);
break;
/* src_reg = atomic_fetch_<op>(dst_reg + off16, src_reg) */
case BPF_ADD | BPF_FETCH:
emit(is64 ? rv_amoadd_d(rs, rs, rd, 1, 1) :
rv_amoadd_w(rs, rs, rd, 1, 1), ctx);
if (!is64)
emit_zextw(rs, rs, ctx);
break;
case BPF_AND | BPF_FETCH:
emit(is64 ? rv_amoand_d(rs, rs, rd, 1, 1) :
rv_amoand_w(rs, rs, rd, 1, 1), ctx);
if (!is64)
emit_zextw(rs, rs, ctx);
break;
case BPF_OR | BPF_FETCH:
emit(is64 ? rv_amoor_d(rs, rs, rd, 1, 1) :
rv_amoor_w(rs, rs, rd, 1, 1), ctx);
if (!is64)
emit_zextw(rs, rs, ctx);
break;
case BPF_XOR | BPF_FETCH:
emit(is64 ? rv_amoxor_d(rs, rs, rd, 1, 1) :
rv_amoxor_w(rs, rs, rd, 1, 1), ctx);
if (!is64)
emit_zextw(rs, rs, ctx);
break;
/* src_reg = atomic_xchg(dst_reg + off16, src_reg); */
case BPF_XCHG:
emit(is64 ? rv_amoswap_d(rs, rs, rd, 1, 1) :
rv_amoswap_w(rs, rs, rd, 1, 1), ctx);
if (!is64)
emit_zextw(rs, rs, ctx);
break;
/* r0 = atomic_cmpxchg(dst_reg + off16, r0, src_reg); */
case BPF_CMPXCHG:
r0 = bpf_to_rv_reg(BPF_REG_0, ctx);
if (is64)
emit_mv(RV_REG_T2, r0, ctx);
else
emit_addiw(RV_REG_T2, r0, 0, ctx);
emit(is64 ? rv_lr_d(r0, 0, rd, 0, 0) :
rv_lr_w(r0, 0, rd, 0, 0), ctx);
jmp_offset = ninsns_rvoff(8);
emit(rv_bne(RV_REG_T2, r0, jmp_offset >> 1), ctx);
emit(is64 ? rv_sc_d(RV_REG_T3, rs, rd, 0, 1) :
rv_sc_w(RV_REG_T3, rs, rd, 0, 1), ctx);
jmp_offset = ninsns_rvoff(-6);
emit(rv_bne(RV_REG_T3, 0, jmp_offset >> 1), ctx);
emit(rv_fence(0x3, 0x3), ctx);
break;
}
}
#define BPF_FIXUP_OFFSET_MASK GENMASK(26, 0)
#define BPF_FIXUP_REG_MASK GENMASK(31, 27)
#define REG_DONT_CLEAR_MARKER 0 /* RV_REG_ZERO unused in pt_regmap */
bool ex_handler_bpf(const struct exception_table_entry *ex,
struct pt_regs *regs)
{
off_t offset = FIELD_GET(BPF_FIXUP_OFFSET_MASK, ex->fixup);
int regs_offset = FIELD_GET(BPF_FIXUP_REG_MASK, ex->fixup);
if (regs_offset != REG_DONT_CLEAR_MARKER)
*(unsigned long *)((void *)regs + pt_regmap[regs_offset]) = 0;
regs->epc = (unsigned long)&ex->fixup - offset;
return true;
}
/* For accesses to BTF pointers, add an entry to the exception table */
static int add_exception_handler(const struct bpf_insn *insn,
struct rv_jit_context *ctx,
int dst_reg, int insn_len)
{
struct exception_table_entry *ex;
unsigned long pc;
off_t ins_offset;
off_t fixup_offset;
if (!ctx->insns || !ctx->ro_insns || !ctx->prog->aux->extable ||
(BPF_MODE(insn->code) != BPF_PROBE_MEM && BPF_MODE(insn->code) != BPF_PROBE_MEMSX &&
BPF_MODE(insn->code) != BPF_PROBE_MEM32))
return 0;
if (WARN_ON_ONCE(ctx->nexentries >= ctx->prog->aux->num_exentries))
return -EINVAL;
if (WARN_ON_ONCE(insn_len > ctx->ninsns))
return -EINVAL;
if (WARN_ON_ONCE(!rvc_enabled() && insn_len == 1))
return -EINVAL;
ex = &ctx->prog->aux->extable[ctx->nexentries];
pc = (unsigned long)&ctx->ro_insns[ctx->ninsns - insn_len];
/*
* This is the relative offset of the instruction that may fault from
* the exception table itself. This will be written to the exception
* table and if this instruction faults, the destination register will
* be set to '0' and the execution will jump to the next instruction.
*/
ins_offset = pc - (long)&ex->insn;
if (WARN_ON_ONCE(ins_offset >= 0 || ins_offset < INT_MIN))
return -ERANGE;
/*
* Since the extable follows the program, the fixup offset is always
* negative and limited to BPF_JIT_REGION_SIZE. Store a positive value
* to keep things simple, and put the destination register in the upper
* bits. We don't need to worry about buildtime or runtime sort
* modifying the upper bits because the table is already sorted, and
* isn't part of the main exception table.
*
* The fixup_offset is set to the next instruction from the instruction
* that may fault. The execution will jump to this after handling the
* fault.
*/
fixup_offset = (long)&ex->fixup - (pc + insn_len * sizeof(u16));
if (!FIELD_FIT(BPF_FIXUP_OFFSET_MASK, fixup_offset))
return -ERANGE;
/*
* The offsets above have been calculated using the RO buffer but we
* need to use the R/W buffer for writes.
* switch ex to rw buffer for writing.
*/
ex = (void *)ctx->insns + ((void *)ex - (void *)ctx->ro_insns);
ex->insn = ins_offset;
ex->fixup = FIELD_PREP(BPF_FIXUP_OFFSET_MASK, fixup_offset) |
FIELD_PREP(BPF_FIXUP_REG_MASK, dst_reg);
ex->type = EX_TYPE_BPF;
ctx->nexentries++;
return 0;
}
static int gen_jump_or_nops(void *target, void *ip, u32 *insns, bool is_call)
{
s64 rvoff;
struct rv_jit_context ctx;
ctx.ninsns = 0;
ctx.insns = (u16 *)insns;
if (!target) {
emit(rv_nop(), &ctx);
emit(rv_nop(), &ctx);
return 0;
}
rvoff = (s64)(target - ip);
return emit_jump_and_link(is_call ? RV_REG_T0 : RV_REG_ZERO, rvoff, false, &ctx);
}
int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type poke_type,
void *old_addr, void *new_addr)
{
u32 old_insns[RV_FENTRY_NINSNS], new_insns[RV_FENTRY_NINSNS];
bool is_call = poke_type == BPF_MOD_CALL;
int ret;
if (!is_kernel_text((unsigned long)ip) &&
!is_bpf_text_address((unsigned long)ip))
return -ENOTSUPP;
ret = gen_jump_or_nops(old_addr, ip, old_insns, is_call);
if (ret)
return ret;
if (memcmp(ip, old_insns, RV_FENTRY_NBYTES))
return -EFAULT;
ret = gen_jump_or_nops(new_addr, ip, new_insns, is_call);
if (ret)
return ret;
cpus_read_lock();
mutex_lock(&text_mutex);
if (memcmp(ip, new_insns, RV_FENTRY_NBYTES))
ret = patch_text(ip, new_insns, RV_FENTRY_NBYTES);
mutex_unlock(&text_mutex);
cpus_read_unlock();
return ret;
}
static void store_args(int nr_arg_slots, int args_off, struct rv_jit_context *ctx)
{
int i;
for (i = 0; i < nr_arg_slots; i++) {
if (i < RV_MAX_REG_ARGS) {
emit_sd(RV_REG_FP, -args_off, RV_REG_A0 + i, ctx);
} else {
/* skip slots for T0 and FP of traced function */
emit_ld(RV_REG_T1, 16 + (i - RV_MAX_REG_ARGS) * 8, RV_REG_FP, ctx);
emit_sd(RV_REG_FP, -args_off, RV_REG_T1, ctx);
}
args_off -= 8;
}
}
static void restore_args(int nr_reg_args, int args_off, struct rv_jit_context *ctx)
{
int i;
for (i = 0; i < nr_reg_args; i++) {
emit_ld(RV_REG_A0 + i, -args_off, RV_REG_FP, ctx);
args_off -= 8;
}
}
static void restore_stack_args(int nr_stack_args, int args_off, int stk_arg_off,
struct rv_jit_context *ctx)
{
int i;
for (i = 0; i < nr_stack_args; i++) {
emit_ld(RV_REG_T1, -(args_off - RV_MAX_REG_ARGS * 8), RV_REG_FP, ctx);
emit_sd(RV_REG_FP, -stk_arg_off, RV_REG_T1, ctx);
args_off -= 8;
stk_arg_off -= 8;
}
}
static int invoke_bpf_prog(struct bpf_tramp_link *l, int args_off, int retval_off,
int run_ctx_off, bool save_ret, struct rv_jit_context *ctx)
{
int ret, branch_off;
struct bpf_prog *p = l->link.prog;
int cookie_off = offsetof(struct bpf_tramp_run_ctx, bpf_cookie);
if (l->cookie) {
emit_imm(RV_REG_T1, l->cookie, ctx);
emit_sd(RV_REG_FP, -run_ctx_off + cookie_off, RV_REG_T1, ctx);
} else {
emit_sd(RV_REG_FP, -run_ctx_off + cookie_off, RV_REG_ZERO, ctx);
}
/* arg1: prog */
emit_imm(RV_REG_A0, (const s64)p, ctx);
/* arg2: &run_ctx */
emit_addi(RV_REG_A1, RV_REG_FP, -run_ctx_off, ctx);
ret = emit_call((const u64)bpf_trampoline_enter(p), true, ctx);
if (ret)
return ret;
/* store prog start time */
emit_mv(RV_REG_S1, RV_REG_A0, ctx);
/* if (__bpf_prog_enter(prog) == 0)
* goto skip_exec_of_prog;
*/
branch_off = ctx->ninsns;
/* nop reserved for conditional jump */
emit(rv_nop(), ctx);
/* arg1: &args_off */
emit_addi(RV_REG_A0, RV_REG_FP, -args_off, ctx);
if (!p->jited)
/* arg2: progs[i]->insnsi for interpreter */
emit_imm(RV_REG_A1, (const s64)p->insnsi, ctx);
ret = emit_call((const u64)p->bpf_func, true, ctx);
if (ret)
return ret;
if (save_ret) {
emit_sd(RV_REG_FP, -retval_off, RV_REG_A0, ctx);
emit_sd(RV_REG_FP, -(retval_off - 8), regmap[BPF_REG_0], ctx);
}
/* update branch with beqz */
if (ctx->insns) {
int offset = ninsns_rvoff(ctx->ninsns - branch_off);
u32 insn = rv_beq(RV_REG_A0, RV_REG_ZERO, offset >> 1);
*(u32 *)(ctx->insns + branch_off) = insn;
}
/* arg1: prog */
emit_imm(RV_REG_A0, (const s64)p, ctx);
/* arg2: prog start time */
emit_mv(RV_REG_A1, RV_REG_S1, ctx);
/* arg3: &run_ctx */
emit_addi(RV_REG_A2, RV_REG_FP, -run_ctx_off, ctx);
ret = emit_call((const u64)bpf_trampoline_exit(p), true, ctx);
return ret;
}
static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im,
const struct btf_func_model *m,
struct bpf_tramp_links *tlinks,
void *func_addr, u32 flags,
struct rv_jit_context *ctx)
{
int i, ret, offset;
int *branches_off = NULL;
int stack_size = 0, nr_arg_slots = 0;
int retval_off, args_off, nregs_off, ip_off, run_ctx_off, sreg_off, stk_arg_off;
struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY];
struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT];
struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN];
bool is_struct_ops = flags & BPF_TRAMP_F_INDIRECT;
void *orig_call = func_addr;
bool save_ret;
u32 insn;
/* Two types of generated trampoline stack layout:
*
* 1. trampoline called from function entry
* --------------------------------------
* FP + 8 [ RA to parent func ] return address to parent
* function
* FP + 0 [ FP of parent func ] frame pointer of parent
* function
* FP - 8 [ T0 to traced func ] return address of traced
* function
* FP - 16 [ FP of traced func ] frame pointer of traced
* function
* --------------------------------------
*
* 2. trampoline called directly
* --------------------------------------
* FP - 8 [ RA to caller func ] return address to caller
* function
* FP - 16 [ FP of caller func ] frame pointer of caller
* function
* --------------------------------------
*
* FP - retval_off [ return value ] BPF_TRAMP_F_CALL_ORIG or
* BPF_TRAMP_F_RET_FENTRY_RET
* [ argN ]
* [ ... ]
* FP - args_off [ arg1 ]
*
* FP - nregs_off [ regs count ]
*
* FP - ip_off [ traced func ] BPF_TRAMP_F_IP_ARG
*
* FP - run_ctx_off [ bpf_tramp_run_ctx ]
*
* FP - sreg_off [ callee saved reg ]
*
* [ pads ] pads for 16 bytes alignment
*
* [ stack_argN ]
* [ ... ]
* FP - stk_arg_off [ stack_arg1 ] BPF_TRAMP_F_CALL_ORIG
*/
if (flags & (BPF_TRAMP_F_ORIG_STACK | BPF_TRAMP_F_SHARE_IPMODIFY))
return -ENOTSUPP;
if (m->nr_args > MAX_BPF_FUNC_ARGS)
return -ENOTSUPP;
for (i = 0; i < m->nr_args; i++)
nr_arg_slots += round_up(m->arg_size[i], 8) / 8;
/* room of trampoline frame to store return address and frame pointer */
stack_size += 16;
save_ret = flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET);
if (save_ret) {
stack_size += 16; /* Save both A5 (BPF R0) and A0 */
retval_off = stack_size;
}
stack_size += nr_arg_slots * 8;
args_off = stack_size;
stack_size += 8;
nregs_off = stack_size;
if (flags & BPF_TRAMP_F_IP_ARG) {
stack_size += 8;
ip_off = stack_size;
}
stack_size += round_up(sizeof(struct bpf_tramp_run_ctx), 8);
run_ctx_off = stack_size;
stack_size += 8;
sreg_off = stack_size;
if ((flags & BPF_TRAMP_F_CALL_ORIG) && (nr_arg_slots - RV_MAX_REG_ARGS > 0))
stack_size += (nr_arg_slots - RV_MAX_REG_ARGS) * 8;
stack_size = round_up(stack_size, STACK_ALIGN);
/* room for args on stack must be at the top of stack */
stk_arg_off = stack_size;
if (!is_struct_ops) {
/* For the trampoline called from function entry,
* the frame of traced function and the frame of
* trampoline need to be considered.
*/
emit_addi(RV_REG_SP, RV_REG_SP, -16, ctx);
emit_sd(RV_REG_SP, 8, RV_REG_RA, ctx);
emit_sd(RV_REG_SP, 0, RV_REG_FP, ctx);
emit_addi(RV_REG_FP, RV_REG_SP, 16, ctx);
emit_addi(RV_REG_SP, RV_REG_SP, -stack_size, ctx);
emit_sd(RV_REG_SP, stack_size - 8, RV_REG_T0, ctx);
emit_sd(RV_REG_SP, stack_size - 16, RV_REG_FP, ctx);
emit_addi(RV_REG_FP, RV_REG_SP, stack_size, ctx);
} else {
/* emit kcfi hash */
emit_kcfi(cfi_get_func_hash(func_addr), ctx);
/* For the trampoline called directly, just handle
* the frame of trampoline.
*/
emit_addi(RV_REG_SP, RV_REG_SP, -stack_size, ctx);
emit_sd(RV_REG_SP, stack_size - 8, RV_REG_RA, ctx);
emit_sd(RV_REG_SP, stack_size - 16, RV_REG_FP, ctx);
emit_addi(RV_REG_FP, RV_REG_SP, stack_size, ctx);
}
/* callee saved register S1 to pass start time */
emit_sd(RV_REG_FP, -sreg_off, RV_REG_S1, ctx);
/* store ip address of the traced function */
if (flags & BPF_TRAMP_F_IP_ARG) {
emit_imm(RV_REG_T1, (const s64)func_addr, ctx);
emit_sd(RV_REG_FP, -ip_off, RV_REG_T1, ctx);
}
emit_li(RV_REG_T1, nr_arg_slots, ctx);
emit_sd(RV_REG_FP, -nregs_off, RV_REG_T1, ctx);
store_args(nr_arg_slots, args_off, ctx);
/* skip to actual body of traced function */
if (flags & BPF_TRAMP_F_SKIP_FRAME)
orig_call += RV_FENTRY_NINSNS * 4;
if (flags & BPF_TRAMP_F_CALL_ORIG) {
emit_imm(RV_REG_A0, ctx->insns ? (const s64)im : RV_MAX_COUNT_IMM, ctx);
ret = emit_call((const u64)__bpf_tramp_enter, true, ctx);
if (ret)
return ret;
}
for (i = 0; i < fentry->nr_links; i++) {
ret = invoke_bpf_prog(fentry->links[i], args_off, retval_off, run_ctx_off,
flags & BPF_TRAMP_F_RET_FENTRY_RET, ctx);
if (ret)
return ret;
}
if (fmod_ret->nr_links) {
branches_off = kcalloc(fmod_ret->nr_links, sizeof(int), GFP_KERNEL);
if (!branches_off)
return -ENOMEM;
/* cleanup to avoid garbage return value confusion */
emit_sd(RV_REG_FP, -retval_off, RV_REG_ZERO, ctx);
for (i = 0; i < fmod_ret->nr_links; i++) {
ret = invoke_bpf_prog(fmod_ret->links[i], args_off, retval_off,
run_ctx_off, true, ctx);
if (ret)
goto out;
emit_ld(RV_REG_T1, -retval_off, RV_REG_FP, ctx);
branches_off[i] = ctx->ninsns;
/* nop reserved for conditional jump */
emit(rv_nop(), ctx);
}
}
if (flags & BPF_TRAMP_F_CALL_ORIG) {
restore_args(min_t(int, nr_arg_slots, RV_MAX_REG_ARGS), args_off, ctx);
restore_stack_args(nr_arg_slots - RV_MAX_REG_ARGS, args_off, stk_arg_off, ctx);
ret = emit_call((const u64)orig_call, true, ctx);
if (ret)
goto out;
emit_sd(RV_REG_FP, -retval_off, RV_REG_A0, ctx);
emit_sd(RV_REG_FP, -(retval_off - 8), regmap[BPF_REG_0], ctx);
im->ip_after_call = ctx->ro_insns + ctx->ninsns;
/* 2 nops reserved for auipc+jalr pair */
emit(rv_nop(), ctx);
emit(rv_nop(), ctx);
}
/* update branches saved in invoke_bpf_mod_ret with bnez */
for (i = 0; ctx->insns && i < fmod_ret->nr_links; i++) {
offset = ninsns_rvoff(ctx->ninsns - branches_off[i]);
insn = rv_bne(RV_REG_T1, RV_REG_ZERO, offset >> 1);
*(u32 *)(ctx->insns + branches_off[i]) = insn;
}
for (i = 0; i < fexit->nr_links; i++) {
ret = invoke_bpf_prog(fexit->links[i], args_off, retval_off,
run_ctx_off, false, ctx);
if (ret)
goto out;
}
if (flags & BPF_TRAMP_F_CALL_ORIG) {
im->ip_epilogue = ctx->ro_insns + ctx->ninsns;
emit_imm(RV_REG_A0, ctx->insns ? (const s64)im : RV_MAX_COUNT_IMM, ctx);
ret = emit_call((const u64)__bpf_tramp_exit, true, ctx);
if (ret)
goto out;
}
if (flags & BPF_TRAMP_F_RESTORE_REGS)
restore_args(min_t(int, nr_arg_slots, RV_MAX_REG_ARGS), args_off, ctx);
if (save_ret) {
emit_ld(RV_REG_A0, -retval_off, RV_REG_FP, ctx);
emit_ld(regmap[BPF_REG_0], -(retval_off - 8), RV_REG_FP, ctx);
}
emit_ld(RV_REG_S1, -sreg_off, RV_REG_FP, ctx);
if (!is_struct_ops) {
/* trampoline called from function entry */
emit_ld(RV_REG_T0, stack_size - 8, RV_REG_SP, ctx);
emit_ld(RV_REG_FP, stack_size - 16, RV_REG_SP, ctx);
emit_addi(RV_REG_SP, RV_REG_SP, stack_size, ctx);
emit_ld(RV_REG_RA, 8, RV_REG_SP, ctx);
emit_ld(RV_REG_FP, 0, RV_REG_SP, ctx);
emit_addi(RV_REG_SP, RV_REG_SP, 16, ctx);
if (flags & BPF_TRAMP_F_SKIP_FRAME)
/* return to parent function */
emit_jalr(RV_REG_ZERO, RV_REG_RA, 0, ctx);
else
/* return to traced function */
emit_jalr(RV_REG_ZERO, RV_REG_T0, 0, ctx);
} else {
/* trampoline called directly */
emit_ld(RV_REG_RA, stack_size - 8, RV_REG_SP, ctx);
emit_ld(RV_REG_FP, stack_size - 16, RV_REG_SP, ctx);
emit_addi(RV_REG_SP, RV_REG_SP, stack_size, ctx);
emit_jalr(RV_REG_ZERO, RV_REG_RA, 0, ctx);
}
ret = ctx->ninsns;
out:
kfree(branches_off);
return ret;
}
int arch_bpf_trampoline_size(const struct btf_func_model *m, u32 flags,
struct bpf_tramp_links *tlinks, void *func_addr)
{
struct bpf_tramp_image im;
struct rv_jit_context ctx;
int ret;
ctx.ninsns = 0;
ctx.insns = NULL;
ctx.ro_insns = NULL;
ret = __arch_prepare_bpf_trampoline(&im, m, tlinks, func_addr, flags, &ctx);
return ret < 0 ? ret : ninsns_rvoff(ctx.ninsns);
}
void *arch_alloc_bpf_trampoline(unsigned int size)
{
return bpf_prog_pack_alloc(size, bpf_fill_ill_insns);
}
void arch_free_bpf_trampoline(void *image, unsigned int size)
{
bpf_prog_pack_free(image, size);
}
int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *ro_image,
void *ro_image_end, const struct btf_func_model *m,
u32 flags, struct bpf_tramp_links *tlinks,
void *func_addr)
{
int ret;
void *image, *res;
struct rv_jit_context ctx;
u32 size = ro_image_end - ro_image;
image = kvmalloc(size, GFP_KERNEL);
if (!image)
return -ENOMEM;
ctx.ninsns = 0;
ctx.insns = image;
ctx.ro_insns = ro_image;
ret = __arch_prepare_bpf_trampoline(im, m, tlinks, func_addr, flags, &ctx);
if (ret < 0)
goto out;
if (WARN_ON(size < ninsns_rvoff(ctx.ninsns))) {
ret = -E2BIG;
goto out;
}
res = bpf_arch_text_copy(ro_image, image, size);
if (IS_ERR(res)) {
ret = PTR_ERR(res);
goto out;
}
bpf_flush_icache(ro_image, ro_image_end);
out:
kvfree(image);
return ret < 0 ? ret : size;
}
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, ret, i = insn - ctx->prog->insnsi;
struct bpf_prog_aux *aux = ctx->prog->aux;
u8 rd = -1, rs = -1, code = insn->code;
s16 off = insn->off;
s32 imm = insn->imm;
init_regs(&rd, &rs, insn, ctx);
switch (code) {
/* dst = src */
case BPF_ALU | BPF_MOV | BPF_X:
case BPF_ALU64 | BPF_MOV | BPF_X:
if (insn_is_cast_user(insn)) {
emit_mv(RV_REG_T1, rs, ctx);
emit_zextw(RV_REG_T1, RV_REG_T1, ctx);
emit_imm(rd, (ctx->user_vm_start >> 32) << 32, ctx);
emit(rv_beq(RV_REG_T1, RV_REG_ZERO, 4), ctx);
emit_or(RV_REG_T1, rd, RV_REG_T1, ctx);
emit_mv(rd, RV_REG_T1, ctx);
break;
} else if (insn_is_mov_percpu_addr(insn)) {
if (rd != rs)
emit_mv(rd, rs, ctx);
#ifdef CONFIG_SMP
/* Load current CPU number in T1 */
emit_ld(RV_REG_T1, offsetof(struct thread_info, cpu),
RV_REG_TP, ctx);
/* Load address of __per_cpu_offset array in T2 */
emit_addr(RV_REG_T2, (u64)&__per_cpu_offset, extra_pass, ctx);
/* Get address of __per_cpu_offset[cpu] in T1 */
emit_sh3add(RV_REG_T1, RV_REG_T1, RV_REG_T2, ctx);
/* Load __per_cpu_offset[cpu] in T1 */
emit_ld(RV_REG_T1, 0, RV_REG_T1, ctx);
/* Add the offset to Rd */
emit_add(rd, rd, RV_REG_T1, ctx);
#endif
}
if (imm == 1) {
/* Special mov32 for zext */
emit_zextw(rd, rd, ctx);
break;
}
switch (insn->off) {
case 0:
emit_mv(rd, rs, ctx);
break;
case 8:
emit_sextb(rd, rs, ctx);
break;
case 16:
emit_sexth(rd, rs, ctx);
break;
case 32:
emit_sextw(rd, rs, ctx);
break;
}
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
/* dst = dst OP src */
case BPF_ALU | BPF_ADD | BPF_X:
case BPF_ALU64 | BPF_ADD | BPF_X:
emit_add(rd, rd, rs, ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_SUB | BPF_X:
case BPF_ALU64 | BPF_SUB | BPF_X:
if (is64)
emit_sub(rd, rd, rs, ctx);
else
emit_subw(rd, rd, rs, ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_AND | BPF_X:
case BPF_ALU64 | BPF_AND | BPF_X:
emit_and(rd, rd, rs, ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_OR | BPF_X:
case BPF_ALU64 | BPF_OR | BPF_X:
emit_or(rd, rd, rs, ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_XOR | BPF_X:
case BPF_ALU64 | BPF_XOR | BPF_X:
emit_xor(rd, rd, rs, ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_MUL | BPF_X:
case BPF_ALU64 | BPF_MUL | BPF_X:
emit(is64 ? rv_mul(rd, rd, rs) : rv_mulw(rd, rd, rs), ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_DIV | BPF_X:
case BPF_ALU64 | BPF_DIV | BPF_X:
if (off)
emit(is64 ? rv_div(rd, rd, rs) : rv_divw(rd, rd, rs), ctx);
else
emit(is64 ? rv_divu(rd, rd, rs) : rv_divuw(rd, rd, rs), ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_MOD | BPF_X:
case BPF_ALU64 | BPF_MOD | BPF_X:
if (off)
emit(is64 ? rv_rem(rd, rd, rs) : rv_remw(rd, rd, rs), ctx);
else
emit(is64 ? rv_remu(rd, rd, rs) : rv_remuw(rd, rd, rs), ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_LSH | BPF_X:
case BPF_ALU64 | BPF_LSH | BPF_X:
emit(is64 ? rv_sll(rd, rd, rs) : rv_sllw(rd, rd, rs), ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_RSH | BPF_X:
case BPF_ALU64 | BPF_RSH | BPF_X:
emit(is64 ? rv_srl(rd, rd, rs) : rv_srlw(rd, rd, rs), ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_ARSH | BPF_X:
case BPF_ALU64 | BPF_ARSH | BPF_X:
emit(is64 ? rv_sra(rd, rd, rs) : rv_sraw(rd, rd, rs), ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
/* dst = -dst */
case BPF_ALU | BPF_NEG:
case BPF_ALU64 | BPF_NEG:
emit_sub(rd, RV_REG_ZERO, rd, ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
/* dst = BSWAP##imm(dst) */
case BPF_ALU | BPF_END | BPF_FROM_LE:
switch (imm) {
case 16:
emit_zexth(rd, rd, ctx);
break;
case 32:
if (!aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case 64:
/* Do nothing */
break;
}
break;
case BPF_ALU | BPF_END | BPF_FROM_BE:
case BPF_ALU64 | BPF_END | BPF_FROM_LE:
emit_bswap(rd, imm, ctx);
break;
/* dst = imm */
case BPF_ALU | BPF_MOV | BPF_K:
case BPF_ALU64 | BPF_MOV | BPF_K:
emit_imm(rd, imm, ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
/* dst = dst OP imm */
case BPF_ALU | BPF_ADD | BPF_K:
case BPF_ALU64 | BPF_ADD | BPF_K:
if (is_12b_int(imm)) {
emit_addi(rd, rd, imm, ctx);
} else {
emit_imm(RV_REG_T1, imm, ctx);
emit_add(rd, rd, RV_REG_T1, ctx);
}
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_SUB | BPF_K:
case BPF_ALU64 | BPF_SUB | BPF_K:
if (is_12b_int(-imm)) {
emit_addi(rd, rd, -imm, ctx);
} else {
emit_imm(RV_REG_T1, imm, ctx);
emit_sub(rd, rd, RV_REG_T1, ctx);
}
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_AND | BPF_K:
case BPF_ALU64 | BPF_AND | BPF_K:
if (is_12b_int(imm)) {
emit_andi(rd, rd, imm, ctx);
} else {
emit_imm(RV_REG_T1, imm, ctx);
emit_and(rd, rd, RV_REG_T1, ctx);
}
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_OR | BPF_K:
case BPF_ALU64 | BPF_OR | BPF_K:
if (is_12b_int(imm)) {
emit(rv_ori(rd, rd, imm), ctx);
} else {
emit_imm(RV_REG_T1, imm, ctx);
emit_or(rd, rd, RV_REG_T1, ctx);
}
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_XOR | BPF_K:
case BPF_ALU64 | BPF_XOR | BPF_K:
if (is_12b_int(imm)) {
emit(rv_xori(rd, rd, imm), ctx);
} else {
emit_imm(RV_REG_T1, imm, ctx);
emit_xor(rd, rd, RV_REG_T1, ctx);
}
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_MUL | BPF_K:
case BPF_ALU64 | BPF_MUL | BPF_K:
emit_imm(RV_REG_T1, imm, ctx);
emit(is64 ? rv_mul(rd, rd, RV_REG_T1) :
rv_mulw(rd, rd, RV_REG_T1), ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_DIV | BPF_K:
case BPF_ALU64 | BPF_DIV | BPF_K:
emit_imm(RV_REG_T1, imm, ctx);
if (off)
emit(is64 ? rv_div(rd, rd, RV_REG_T1) :
rv_divw(rd, rd, RV_REG_T1), ctx);
else
emit(is64 ? rv_divu(rd, rd, RV_REG_T1) :
rv_divuw(rd, rd, RV_REG_T1), ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_MOD | BPF_K:
case BPF_ALU64 | BPF_MOD | BPF_K:
emit_imm(RV_REG_T1, imm, ctx);
if (off)
emit(is64 ? rv_rem(rd, rd, RV_REG_T1) :
rv_remw(rd, rd, RV_REG_T1), ctx);
else
emit(is64 ? rv_remu(rd, rd, RV_REG_T1) :
rv_remuw(rd, rd, RV_REG_T1), ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_LSH | BPF_K:
case BPF_ALU64 | BPF_LSH | BPF_K:
emit_slli(rd, rd, imm, ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_RSH | BPF_K:
case BPF_ALU64 | BPF_RSH | BPF_K:
if (is64)
emit_srli(rd, rd, imm, ctx);
else
emit(rv_srliw(rd, rd, imm), ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
case BPF_ALU | BPF_ARSH | BPF_K:
case BPF_ALU64 | BPF_ARSH | BPF_K:
if (is64)
emit_srai(rd, rd, imm, ctx);
else
emit(rv_sraiw(rd, rd, imm), ctx);
if (!is64 && !aux->verifier_zext)
emit_zextw(rd, rd, ctx);
break;
/* JUMP off */
case BPF_JMP | BPF_JA:
case BPF_JMP32 | BPF_JA:
if (BPF_CLASS(code) == BPF_JMP)
rvoff = rv_offset(i, off, ctx);
else
rvoff = rv_offset(i, imm, ctx);
ret = emit_jump_and_link(RV_REG_ZERO, rvoff, true, ctx);
if (ret)
return ret;
break;
/* IF (dst COND src) JUMP off */
case BPF_JMP | BPF_JEQ | BPF_X:
case BPF_JMP32 | BPF_JEQ | BPF_X:
case BPF_JMP | BPF_JGT | BPF_X:
case BPF_JMP32 | BPF_JGT | BPF_X:
case BPF_JMP | BPF_JLT | BPF_X:
case BPF_JMP32 | BPF_JLT | BPF_X:
case BPF_JMP | BPF_JGE | BPF_X:
case BPF_JMP32 | BPF_JGE | BPF_X:
case BPF_JMP | BPF_JLE | BPF_X:
case BPF_JMP32 | BPF_JLE | BPF_X:
case BPF_JMP | BPF_JNE | BPF_X:
case BPF_JMP32 | BPF_JNE | BPF_X:
case BPF_JMP | BPF_JSGT | BPF_X:
case BPF_JMP32 | BPF_JSGT | BPF_X:
case BPF_JMP | BPF_JSLT | BPF_X:
case BPF_JMP32 | BPF_JSLT | BPF_X:
case BPF_JMP | BPF_JSGE | BPF_X:
case BPF_JMP32 | BPF_JSGE | BPF_X:
case BPF_JMP | BPF_JSLE | BPF_X:
case BPF_JMP32 | BPF_JSLE | BPF_X:
case BPF_JMP | BPF_JSET | BPF_X:
case BPF_JMP32 | BPF_JSET | BPF_X:
rvoff = rv_offset(i, off, ctx);
if (!is64) {
s = ctx->ninsns;
if (is_signed_bpf_cond(BPF_OP(code))) {
emit_sextw_alt(&rs, RV_REG_T1, ctx);
emit_sextw_alt(&rd, RV_REG_T2, ctx);
} else {
emit_zextw_alt(&rs, RV_REG_T1, ctx);
emit_zextw_alt(&rd, RV_REG_T2, ctx);
}
e = ctx->ninsns;
/* Adjust for extra insns */
rvoff -= ninsns_rvoff(e - s);
}
if (BPF_OP(code) == BPF_JSET) {
/* Adjust for and */
rvoff -= 4;
emit_and(RV_REG_T1, rd, rs, ctx);
emit_branch(BPF_JNE, RV_REG_T1, RV_REG_ZERO, rvoff, ctx);
} else {
emit_branch(BPF_OP(code), rd, rs, rvoff, ctx);
}
break;
/* IF (dst COND imm) JUMP off */
case BPF_JMP | BPF_JEQ | BPF_K:
case BPF_JMP32 | BPF_JEQ | BPF_K:
case BPF_JMP | BPF_JGT | BPF_K:
case BPF_JMP32 | BPF_JGT | BPF_K:
case BPF_JMP | BPF_JLT | BPF_K:
case BPF_JMP32 | BPF_JLT | BPF_K:
case BPF_JMP | BPF_JGE | BPF_K:
case BPF_JMP32 | BPF_JGE | BPF_K:
case BPF_JMP | BPF_JLE | BPF_K:
case BPF_JMP32 | BPF_JLE | BPF_K:
case BPF_JMP | BPF_JNE | BPF_K:
case BPF_JMP32 | BPF_JNE | BPF_K:
case BPF_JMP | BPF_JSGT | BPF_K:
case BPF_JMP32 | BPF_JSGT | BPF_K:
case BPF_JMP | BPF_JSLT | BPF_K:
case BPF_JMP32 | BPF_JSLT | BPF_K:
case BPF_JMP | BPF_JSGE | BPF_K:
case BPF_JMP32 | BPF_JSGE | BPF_K:
case BPF_JMP | BPF_JSLE | BPF_K:
case BPF_JMP32 | BPF_JSLE | BPF_K:
rvoff = rv_offset(i, off, ctx);
s = ctx->ninsns;
if (imm)
emit_imm(RV_REG_T1, imm, ctx);
rs = imm ? RV_REG_T1 : RV_REG_ZERO;
if (!is64) {
if (is_signed_bpf_cond(BPF_OP(code))) {
emit_sextw_alt(&rd, RV_REG_T2, ctx);
/* rs has been sign extended */
} else {
emit_zextw_alt(&rd, RV_REG_T2, ctx);
if (imm)
emit_zextw(rs, rs, ctx);
}
}
e = ctx->ninsns;
/* Adjust for extra insns */
rvoff -= ninsns_rvoff(e - s);
emit_branch(BPF_OP(code), rd, rs, rvoff, ctx);
break;
case BPF_JMP | BPF_JSET | BPF_K:
case BPF_JMP32 | BPF_JSET | BPF_K:
rvoff = rv_offset(i, off, ctx);
s = ctx->ninsns;
if (is_12b_int(imm)) {
emit_andi(RV_REG_T1, rd, imm, ctx);
} else {
emit_imm(RV_REG_T1, imm, ctx);
emit_and(RV_REG_T1, rd, RV_REG_T1, ctx);
}
/* For jset32, we should clear the upper 32 bits of t1, but
* sign-extension is sufficient here and saves one instruction,
* as t1 is used only in comparison against zero.
*/
if (!is64 && imm < 0)
emit_sextw(RV_REG_T1, RV_REG_T1, ctx);
e = ctx->ninsns;
rvoff -= ninsns_rvoff(e - s);
emit_branch(BPF_JNE, RV_REG_T1, RV_REG_ZERO, rvoff, ctx);
break;
/* function call */
case BPF_JMP | BPF_CALL:
{
bool fixed_addr;
u64 addr;
/* Inline calls to bpf_get_smp_processor_id()
*
* RV_REG_TP holds the address of the current CPU's task_struct and thread_info is
* at offset 0 in task_struct.
* Load cpu from thread_info:
* Set R0 to ((struct thread_info *)(RV_REG_TP))->cpu
*
* This replicates the implementation of raw_smp_processor_id() on RISCV
*/
if (insn->src_reg == 0 && insn->imm == BPF_FUNC_get_smp_processor_id) {
/* Load current CPU number in R0 */
emit_ld(bpf_to_rv_reg(BPF_REG_0, ctx), offsetof(struct thread_info, cpu),
RV_REG_TP, ctx);
break;
}
mark_call(ctx);
ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass,
&addr, &fixed_addr);
if (ret < 0)
return ret;
if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
const struct btf_func_model *fm;
int idx;
fm = bpf_jit_find_kfunc_model(ctx->prog, insn);
if (!fm)
return -EINVAL;
for (idx = 0; idx < fm->nr_args; idx++) {
u8 reg = bpf_to_rv_reg(BPF_REG_1 + idx, ctx);
if (fm->arg_size[idx] == sizeof(int))
emit_sextw(reg, reg, ctx);
}
}
ret = emit_call(addr, fixed_addr, ctx);
if (ret)
return ret;
if (insn->src_reg != BPF_PSEUDO_CALL)
emit_mv(bpf_to_rv_reg(BPF_REG_0, ctx), RV_REG_A0, ctx);
break;
}
/* tail call */
case BPF_JMP | BPF_TAIL_CALL:
if (emit_bpf_tail_call(i, ctx))
return -1;
break;
/* function return */
case BPF_JMP | BPF_EXIT:
if (i == ctx->prog->len - 1)
break;
rvoff = epilogue_offset(ctx);
ret = emit_jump_and_link(RV_REG_ZERO, rvoff, true, ctx);
if (ret)
return ret;
break;
/* dst = imm64 */
case BPF_LD | BPF_IMM | BPF_DW:
{
struct bpf_insn insn1 = insn[1];
u64 imm64;
imm64 = (u64)insn1.imm << 32 | (u32)imm;
if (bpf_pseudo_func(insn)) {
/* fixed-length insns for extra jit pass */
ret = emit_addr(rd, imm64, extra_pass, ctx);
if (ret)
return ret;
} else {
emit_imm(rd, imm64, ctx);
}
return 1;
}
/* LDX: dst = *(unsigned size *)(src + off) */
case BPF_LDX | BPF_MEM | BPF_B:
case BPF_LDX | BPF_MEM | BPF_H:
case BPF_LDX | BPF_MEM | BPF_W:
case BPF_LDX | BPF_MEM | BPF_DW:
case BPF_LDX | BPF_PROBE_MEM | BPF_B:
case BPF_LDX | BPF_PROBE_MEM | BPF_H:
case BPF_LDX | BPF_PROBE_MEM | BPF_W:
case BPF_LDX | BPF_PROBE_MEM | BPF_DW:
/* LDSX: dst = *(signed size *)(src + off) */
case BPF_LDX | BPF_MEMSX | BPF_B:
case BPF_LDX | BPF_MEMSX | BPF_H:
case BPF_LDX | BPF_MEMSX | BPF_W:
case BPF_LDX | BPF_PROBE_MEMSX | BPF_B:
case BPF_LDX | BPF_PROBE_MEMSX | BPF_H:
case BPF_LDX | BPF_PROBE_MEMSX | BPF_W:
/* LDX | PROBE_MEM32: dst = *(unsigned size *)(src + RV_REG_ARENA + off) */
case BPF_LDX | BPF_PROBE_MEM32 | BPF_B:
case BPF_LDX | BPF_PROBE_MEM32 | BPF_H:
case BPF_LDX | BPF_PROBE_MEM32 | BPF_W:
case BPF_LDX | BPF_PROBE_MEM32 | BPF_DW:
{
int insn_len, insns_start;
bool sign_ext;
sign_ext = BPF_MODE(insn->code) == BPF_MEMSX ||
BPF_MODE(insn->code) == BPF_PROBE_MEMSX;
if (BPF_MODE(insn->code) == BPF_PROBE_MEM32) {
emit_add(RV_REG_T2, rs, RV_REG_ARENA, ctx);
rs = RV_REG_T2;
}
switch (BPF_SIZE(code)) {
case BPF_B:
if (is_12b_int(off)) {
insns_start = ctx->ninsns;
if (sign_ext)
emit(rv_lb(rd, off, rs), ctx);
else
emit(rv_lbu(rd, off, rs), ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
emit_imm(RV_REG_T1, off, ctx);
emit_add(RV_REG_T1, RV_REG_T1, rs, ctx);
insns_start = ctx->ninsns;
if (sign_ext)
emit(rv_lb(rd, 0, RV_REG_T1), ctx);
else
emit(rv_lbu(rd, 0, RV_REG_T1), ctx);
insn_len = ctx->ninsns - insns_start;
break;
case BPF_H:
if (is_12b_int(off)) {
insns_start = ctx->ninsns;
if (sign_ext)
emit(rv_lh(rd, off, rs), ctx);
else
emit(rv_lhu(rd, off, rs), ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
emit_imm(RV_REG_T1, off, ctx);
emit_add(RV_REG_T1, RV_REG_T1, rs, ctx);
insns_start = ctx->ninsns;
if (sign_ext)
emit(rv_lh(rd, 0, RV_REG_T1), ctx);
else
emit(rv_lhu(rd, 0, RV_REG_T1), ctx);
insn_len = ctx->ninsns - insns_start;
break;
case BPF_W:
if (is_12b_int(off)) {
insns_start = ctx->ninsns;
if (sign_ext)
emit(rv_lw(rd, off, rs), ctx);
else
emit(rv_lwu(rd, off, rs), ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
emit_imm(RV_REG_T1, off, ctx);
emit_add(RV_REG_T1, RV_REG_T1, rs, ctx);
insns_start = ctx->ninsns;
if (sign_ext)
emit(rv_lw(rd, 0, RV_REG_T1), ctx);
else
emit(rv_lwu(rd, 0, RV_REG_T1), ctx);
insn_len = ctx->ninsns - insns_start;
break;
case BPF_DW:
if (is_12b_int(off)) {
insns_start = ctx->ninsns;
emit_ld(rd, off, rs, ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
emit_imm(RV_REG_T1, off, ctx);
emit_add(RV_REG_T1, RV_REG_T1, rs, ctx);
insns_start = ctx->ninsns;
emit_ld(rd, 0, RV_REG_T1, ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
ret = add_exception_handler(insn, ctx, rd, insn_len);
if (ret)
return ret;
if (BPF_SIZE(code) != BPF_DW && insn_is_zext(&insn[1]))
return 1;
break;
}
/* speculation barrier */
case BPF_ST | BPF_NOSPEC:
break;
/* ST: *(size *)(dst + off) = imm */
case BPF_ST | BPF_MEM | BPF_B:
emit_imm(RV_REG_T1, imm, ctx);
if (is_12b_int(off)) {
emit(rv_sb(rd, off, RV_REG_T1), ctx);
break;
}
emit_imm(RV_REG_T2, off, ctx);
emit_add(RV_REG_T2, RV_REG_T2, rd, ctx);
emit(rv_sb(RV_REG_T2, 0, RV_REG_T1), ctx);
break;
case BPF_ST | BPF_MEM | BPF_H:
emit_imm(RV_REG_T1, imm, ctx);
if (is_12b_int(off)) {
emit(rv_sh(rd, off, RV_REG_T1), ctx);
break;
}
emit_imm(RV_REG_T2, off, ctx);
emit_add(RV_REG_T2, RV_REG_T2, rd, ctx);
emit(rv_sh(RV_REG_T2, 0, RV_REG_T1), ctx);
break;
case BPF_ST | BPF_MEM | BPF_W:
emit_imm(RV_REG_T1, imm, ctx);
if (is_12b_int(off)) {
emit_sw(rd, off, RV_REG_T1, ctx);
break;
}
emit_imm(RV_REG_T2, off, ctx);
emit_add(RV_REG_T2, RV_REG_T2, rd, ctx);
emit_sw(RV_REG_T2, 0, RV_REG_T1, ctx);
break;
case BPF_ST | BPF_MEM | BPF_DW:
emit_imm(RV_REG_T1, imm, ctx);
if (is_12b_int(off)) {
emit_sd(rd, off, RV_REG_T1, ctx);
break;
}
emit_imm(RV_REG_T2, off, ctx);
emit_add(RV_REG_T2, RV_REG_T2, rd, ctx);
emit_sd(RV_REG_T2, 0, RV_REG_T1, ctx);
break;
case BPF_ST | BPF_PROBE_MEM32 | BPF_B:
case BPF_ST | BPF_PROBE_MEM32 | BPF_H:
case BPF_ST | BPF_PROBE_MEM32 | BPF_W:
case BPF_ST | BPF_PROBE_MEM32 | BPF_DW:
{
int insn_len, insns_start;
emit_add(RV_REG_T3, rd, RV_REG_ARENA, ctx);
rd = RV_REG_T3;
/* Load imm to a register then store it */
emit_imm(RV_REG_T1, imm, ctx);
switch (BPF_SIZE(code)) {
case BPF_B:
if (is_12b_int(off)) {
insns_start = ctx->ninsns;
emit(rv_sb(rd, off, RV_REG_T1), ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
emit_imm(RV_REG_T2, off, ctx);
emit_add(RV_REG_T2, RV_REG_T2, rd, ctx);
insns_start = ctx->ninsns;
emit(rv_sb(RV_REG_T2, 0, RV_REG_T1), ctx);
insn_len = ctx->ninsns - insns_start;
break;
case BPF_H:
if (is_12b_int(off)) {
insns_start = ctx->ninsns;
emit(rv_sh(rd, off, RV_REG_T1), ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
emit_imm(RV_REG_T2, off, ctx);
emit_add(RV_REG_T2, RV_REG_T2, rd, ctx);
insns_start = ctx->ninsns;
emit(rv_sh(RV_REG_T2, 0, RV_REG_T1), ctx);
insn_len = ctx->ninsns - insns_start;
break;
case BPF_W:
if (is_12b_int(off)) {
insns_start = ctx->ninsns;
emit_sw(rd, off, RV_REG_T1, ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
emit_imm(RV_REG_T2, off, ctx);
emit_add(RV_REG_T2, RV_REG_T2, rd, ctx);
insns_start = ctx->ninsns;
emit_sw(RV_REG_T2, 0, RV_REG_T1, ctx);
insn_len = ctx->ninsns - insns_start;
break;
case BPF_DW:
if (is_12b_int(off)) {
insns_start = ctx->ninsns;
emit_sd(rd, off, RV_REG_T1, ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
emit_imm(RV_REG_T2, off, ctx);
emit_add(RV_REG_T2, RV_REG_T2, rd, ctx);
insns_start = ctx->ninsns;
emit_sd(RV_REG_T2, 0, RV_REG_T1, ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
ret = add_exception_handler(insn, ctx, REG_DONT_CLEAR_MARKER,
insn_len);
if (ret)
return ret;
break;
}
/* STX: *(size *)(dst + off) = src */
case BPF_STX | BPF_MEM | BPF_B:
if (is_12b_int(off)) {
emit(rv_sb(rd, off, rs), ctx);
break;
}
emit_imm(RV_REG_T1, off, ctx);
emit_add(RV_REG_T1, RV_REG_T1, rd, ctx);
emit(rv_sb(RV_REG_T1, 0, rs), ctx);
break;
case BPF_STX | BPF_MEM | BPF_H:
if (is_12b_int(off)) {
emit(rv_sh(rd, off, rs), ctx);
break;
}
emit_imm(RV_REG_T1, off, ctx);
emit_add(RV_REG_T1, RV_REG_T1, rd, ctx);
emit(rv_sh(RV_REG_T1, 0, rs), ctx);
break;
case BPF_STX | BPF_MEM | BPF_W:
if (is_12b_int(off)) {
emit_sw(rd, off, rs, ctx);
break;
}
emit_imm(RV_REG_T1, off, ctx);
emit_add(RV_REG_T1, RV_REG_T1, rd, ctx);
emit_sw(RV_REG_T1, 0, rs, ctx);
break;
case BPF_STX | BPF_MEM | BPF_DW:
if (is_12b_int(off)) {
emit_sd(rd, off, rs, ctx);
break;
}
emit_imm(RV_REG_T1, off, ctx);
emit_add(RV_REG_T1, RV_REG_T1, rd, ctx);
emit_sd(RV_REG_T1, 0, rs, ctx);
break;
case BPF_STX | BPF_ATOMIC | BPF_W:
case BPF_STX | BPF_ATOMIC | BPF_DW:
emit_atomic(rd, rs, off, imm,
BPF_SIZE(code) == BPF_DW, ctx);
break;
case BPF_STX | BPF_PROBE_MEM32 | BPF_B:
case BPF_STX | BPF_PROBE_MEM32 | BPF_H:
case BPF_STX | BPF_PROBE_MEM32 | BPF_W:
case BPF_STX | BPF_PROBE_MEM32 | BPF_DW:
{
int insn_len, insns_start;
emit_add(RV_REG_T2, rd, RV_REG_ARENA, ctx);
rd = RV_REG_T2;
switch (BPF_SIZE(code)) {
case BPF_B:
if (is_12b_int(off)) {
insns_start = ctx->ninsns;
emit(rv_sb(rd, off, rs), ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
emit_imm(RV_REG_T1, off, ctx);
emit_add(RV_REG_T1, RV_REG_T1, rd, ctx);
insns_start = ctx->ninsns;
emit(rv_sb(RV_REG_T1, 0, rs), ctx);
insn_len = ctx->ninsns - insns_start;
break;
case BPF_H:
if (is_12b_int(off)) {
insns_start = ctx->ninsns;
emit(rv_sh(rd, off, rs), ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
emit_imm(RV_REG_T1, off, ctx);
emit_add(RV_REG_T1, RV_REG_T1, rd, ctx);
insns_start = ctx->ninsns;
emit(rv_sh(RV_REG_T1, 0, rs), ctx);
insn_len = ctx->ninsns - insns_start;
break;
case BPF_W:
if (is_12b_int(off)) {
insns_start = ctx->ninsns;
emit_sw(rd, off, rs, ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
emit_imm(RV_REG_T1, off, ctx);
emit_add(RV_REG_T1, RV_REG_T1, rd, ctx);
insns_start = ctx->ninsns;
emit_sw(RV_REG_T1, 0, rs, ctx);
insn_len = ctx->ninsns - insns_start;
break;
case BPF_DW:
if (is_12b_int(off)) {
insns_start = ctx->ninsns;
emit_sd(rd, off, rs, ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
emit_imm(RV_REG_T1, off, ctx);
emit_add(RV_REG_T1, RV_REG_T1, rd, ctx);
insns_start = ctx->ninsns;
emit_sd(RV_REG_T1, 0, rs, ctx);
insn_len = ctx->ninsns - insns_start;
break;
}
ret = add_exception_handler(insn, ctx, REG_DONT_CLEAR_MARKER,
insn_len);
if (ret)
return ret;
break;
}
default:
pr_err("bpf-jit: unknown opcode %02x\n", code);
return -EINVAL;
}
return 0;
}
void bpf_jit_build_prologue(struct rv_jit_context *ctx, bool is_subprog)
{
int i, stack_adjust = 0, store_offset, bpf_stack_adjust;
bpf_stack_adjust = round_up(ctx->prog->aux->stack_depth, STACK_ALIGN);
if (bpf_stack_adjust)
mark_fp(ctx);
if (seen_reg(RV_REG_RA, ctx))
stack_adjust += 8;
stack_adjust += 8; /* RV_REG_FP */
if (seen_reg(RV_REG_S1, ctx))
stack_adjust += 8;
if (seen_reg(RV_REG_S2, ctx))
stack_adjust += 8;
if (seen_reg(RV_REG_S3, ctx))
stack_adjust += 8;
if (seen_reg(RV_REG_S4, ctx))
stack_adjust += 8;
if (seen_reg(RV_REG_S5, ctx))
stack_adjust += 8;
if (seen_reg(RV_REG_S6, ctx))
stack_adjust += 8;
if (ctx->arena_vm_start)
stack_adjust += 8;
stack_adjust = round_up(stack_adjust, STACK_ALIGN);
stack_adjust += bpf_stack_adjust;
store_offset = stack_adjust - 8;
/* emit kcfi type preamble immediately before the first insn */
emit_kcfi(is_subprog ? cfi_bpf_subprog_hash : cfi_bpf_hash, ctx);
/* nops reserved for auipc+jalr pair */
for (i = 0; i < RV_FENTRY_NINSNS; i++)
emit(rv_nop(), ctx);
/* First instruction is always setting the tail-call-counter
* (TCC) register. This instruction is skipped for tail calls.
* Force using a 4-byte (non-compressed) instruction.
*/
emit(rv_addi(RV_REG_TCC, RV_REG_ZERO, MAX_TAIL_CALL_CNT), ctx);
emit_addi(RV_REG_SP, RV_REG_SP, -stack_adjust, ctx);
if (seen_reg(RV_REG_RA, ctx)) {
emit_sd(RV_REG_SP, store_offset, RV_REG_RA, ctx);
store_offset -= 8;
}
emit_sd(RV_REG_SP, store_offset, RV_REG_FP, ctx);
store_offset -= 8;
if (seen_reg(RV_REG_S1, ctx)) {
emit_sd(RV_REG_SP, store_offset, RV_REG_S1, ctx);
store_offset -= 8;
}
if (seen_reg(RV_REG_S2, ctx)) {
emit_sd(RV_REG_SP, store_offset, RV_REG_S2, ctx);
store_offset -= 8;
}
if (seen_reg(RV_REG_S3, ctx)) {
emit_sd(RV_REG_SP, store_offset, RV_REG_S3, ctx);
store_offset -= 8;
}
if (seen_reg(RV_REG_S4, ctx)) {
emit_sd(RV_REG_SP, store_offset, RV_REG_S4, ctx);
store_offset -= 8;
}
if (seen_reg(RV_REG_S5, ctx)) {
emit_sd(RV_REG_SP, store_offset, RV_REG_S5, ctx);
store_offset -= 8;
}
if (seen_reg(RV_REG_S6, ctx)) {
emit_sd(RV_REG_SP, store_offset, RV_REG_S6, ctx);
store_offset -= 8;
}
if (ctx->arena_vm_start) {
emit_sd(RV_REG_SP, store_offset, RV_REG_ARENA, ctx);
store_offset -= 8;
}
emit_addi(RV_REG_FP, RV_REG_SP, stack_adjust, ctx);
if (bpf_stack_adjust)
emit_addi(RV_REG_S5, RV_REG_SP, bpf_stack_adjust, ctx);
/* Program contains calls and tail calls, so RV_REG_TCC need
* to be saved across calls.
*/
if (seen_tail_call(ctx) && seen_call(ctx))
emit_mv(RV_REG_TCC_SAVED, RV_REG_TCC, ctx);
ctx->stack_size = stack_adjust;
if (ctx->arena_vm_start)
emit_imm(RV_REG_ARENA, ctx->arena_vm_start, ctx);
}
void bpf_jit_build_epilogue(struct rv_jit_context *ctx)
{
__build_epilogue(false, ctx);
}
bool bpf_jit_supports_kfunc_call(void)
{
return true;
}
bool bpf_jit_supports_ptr_xchg(void)
{
return true;
}
bool bpf_jit_supports_arena(void)
{
return true;
}
bool bpf_jit_supports_percpu_insn(void)
{
return true;
}
bool bpf_jit_inlines_helper_call(s32 imm)
{
switch (imm) {
case BPF_FUNC_get_smp_processor_id:
return true;
default:
return false;
}
}
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