diff options
| author | Yonghong Song <yonghong.song@linux.dev> | 2026-05-13 07:50:05 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-05-13 19:27:30 +0300 |
| commit | 78bbe61632f11b1091c03259f92b6559489222ae (patch) | |
| tree | 4f190494d94576fdce70ea50d84d1885ca367a9a /include/linux | |
| parent | 1cb229a54af1e36f19f7e8359692fa0d76fbc360 (diff) | |
| download | linux-78bbe61632f11b1091c03259f92b6559489222ae.tar.xz | |
bpf: Add helper functions for r11-based stack argument insns
Add three static inline helper functions — is_stack_arg_ldx(),
is_stack_arg_st(), and is_stack_arg_stx() — that identify r11-based
(BPF_REG_PARAMS) instructions used for stack argument passing. These
helpers encapsulate the detailed encoding requirements (operand size,
register, offset alignment and sign) and hide raw BPF_REG_PARAMS usage
from the verifier, making call sites more readable and explicit.
A later patch ("bpf: Enable r11 based insns") will wire these helpers
into the verifier. Until then, check_and_resolve_insns() rejects any
r11-based registers.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20260513045005.2383881-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/filter.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h index b77d0b06db6e..918d9b34eac6 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -749,6 +749,27 @@ static inline u32 bpf_prog_run_pin_on_cpu(const struct bpf_prog *prog, return ret; } +static inline bool is_stack_arg_ldx(const struct bpf_insn *insn) +{ + return insn->code == (BPF_LDX | BPF_MEM | BPF_DW) && + insn->src_reg == BPF_REG_PARAMS && + insn->off > 0 && insn->off % 8 == 0; +} + +static inline bool is_stack_arg_st(const struct bpf_insn *insn) +{ + return insn->code == (BPF_ST | BPF_MEM | BPF_DW) && + insn->dst_reg == BPF_REG_PARAMS && + insn->off < 0 && insn->off % 8 == 0; +} + +static inline bool is_stack_arg_stx(const struct bpf_insn *insn) +{ + return insn->code == (BPF_STX | BPF_MEM | BPF_DW) && + insn->dst_reg == BPF_REG_PARAMS && + insn->off < 0 && insn->off % 8 == 0; +} + #define BPF_SKB_CB_LEN QDISC_CB_PRIV_LEN struct bpf_skb_data_end { |