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LoongArch: BPF: Fix incorrect return pointer value in the eBPF program #5756

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LoongArch: BPF: Fix incorrect return pointer value in the eBPF program #5756

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8 changes: 8 additions & 0 deletions arch/loongarch/include/asm/inst.h
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Original file line number Diff line number Diff line change
Expand Up @@ -92,6 +92,8 @@ enum reg2i6_op {
};

enum reg2i12_op {
slti_op = 0x08,
sltui_op = 0x09,
addiw_op = 0x0a,
addid_op = 0x0b,
lu52id_op = 0x0c,
Expand Down Expand Up @@ -148,6 +150,8 @@ enum reg3_op {
addd_op = 0x21,
subw_op = 0x22,
subd_op = 0x23,
slt_op = 0x24,
sltu_op = 0x25,
nor_op = 0x28,
and_op = 0x29,
or_op = 0x2a,
Expand Down Expand Up @@ -629,6 +633,8 @@ static inline void emit_##NAME(union loongarch_instruction *insn, \
insn->reg2i12_format.rj = rj; \
}

DEF_EMIT_REG2I12_FORMAT(slti, slti_op)
DEF_EMIT_REG2I12_FORMAT(sltui, sltui_op)
DEF_EMIT_REG2I12_FORMAT(addiw, addiw_op)
DEF_EMIT_REG2I12_FORMAT(addid, addid_op)
DEF_EMIT_REG2I12_FORMAT(lu52id, lu52id_op)
Expand Down Expand Up @@ -729,6 +735,8 @@ static inline void emit_##NAME(union loongarch_instruction *insn, \
DEF_EMIT_REG3_FORMAT(addw, addw_op)
DEF_EMIT_REG3_FORMAT(addd, addd_op)
DEF_EMIT_REG3_FORMAT(subd, subd_op)
DEF_EMIT_REG3_FORMAT(slt, slt_op)
DEF_EMIT_REG3_FORMAT(sltu, sltu_op)
DEF_EMIT_REG3_FORMAT(muld, muld_op)
DEF_EMIT_REG3_FORMAT(divd, divd_op)
DEF_EMIT_REG3_FORMAT(modd, modd_op)
Expand Down
17 changes: 15 additions & 2 deletions arch/loongarch/net/bpf_jit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -229,8 +229,21 @@ static void __build_epilogue(struct jit_ctx *ctx, bool is_tail_call)
emit_insn(ctx, addid, LOONGARCH_GPR_SP, LOONGARCH_GPR_SP, stack_adjust);

if (!is_tail_call) {
/* Set return value */
emit_insn(ctx, addiw, LOONGARCH_GPR_A0, regmap[BPF_REG_0], 0);
/*
* Set return value
* Check if the 64th bit in regmap[BPF_REG_0] is 1. If it is,
* the value in regmap[BPF_REG_0] is a kernel-space address.

* long long val = regmap[BPF_REG_0];
* int shift = 0 < val ? 32 : 0;
* return (val << shift) >> shift;
*/
move_reg(ctx, LOONGARCH_GPR_A0, regmap[BPF_REG_0]);
emit_insn(ctx, slt, LOONGARCH_GPR_T0, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_A0);
emit_insn(ctx, sllid, LOONGARCH_GPR_T0, LOONGARCH_GPR_T0, 5);
emit_insn(ctx, slld, LOONGARCH_GPR_A0, LOONGARCH_GPR_A0, LOONGARCH_GPR_T0);
emit_insn(ctx, srad, LOONGARCH_GPR_A0, LOONGARCH_GPR_A0, LOONGARCH_GPR_T0);

/* Return to the caller */
emit_insn(ctx, jirl, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_RA, 0);
} else {
Expand Down
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