From 770546ae9f4c1ae1ebcaf0874f0dd9631d77ec97 Mon Sep 17 00:00:00 2001 From: Puranjay Mohan Date: Sun, 24 Mar 2024 18:32:26 +0000 Subject: bpf: implement insn_is_cast_user() helper for JITs Implement a helper function to check if an instruction is addr_space_cast from as(0) to as(1). Use this helper in the x86 JIT. Other JITs can use this helper when they add support for this instruction. Signed-off-by: Puranjay Mohan Link: https://lore.kernel.org/r/20240324183226.29674-1-puranjay12@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/filter.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include') diff --git a/include/linux/filter.h b/include/linux/filter.h index c0d51bff8f96..44934b968b57 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -228,6 +228,16 @@ static inline bool insn_is_zext(const struct bpf_insn *insn) return insn->code == (BPF_ALU | BPF_MOV | BPF_X) && insn->imm == 1; } +/* addr_space_cast from as(0) to as(1) is for converting bpf arena pointers + * to pointers in user vma. + */ +static inline bool insn_is_cast_user(const struct bpf_insn *insn) +{ + return insn->code == (BPF_ALU64 | BPF_MOV | BPF_X) && + insn->off == BPF_ADDR_SPACE_CAST && + insn->imm == 1U << 16; +} + /* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */ #define BPF_LD_IMM64(DST, IMM) \ BPF_LD_IMM64_RAW(DST, 0, IMM) -- cgit v1.2.3