From 49f67f393ff264e8d83f6fcec0728a6aa8eed102 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Sat, 28 Jan 2023 01:06:44 +0100 Subject: [PATCH] bpf: btf: Add BTF_FMODEL_SIGNED_ARG flag s390x eBPF JIT needs to know whether a function return value is signed and which function arguments are signed, in order to generate code compliant with the s390x ABI. Signed-off-by: Ilya Leoshkevich Link: https://lore.kernel.org/r/20230128000650.1516334-26-iii@linux.ibm.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 4 ++++ include/linux/btf.h | 15 ++++++++++----- kernel/bpf/btf.c | 16 +++++++++++++++- 3 files changed, 29 insertions(+), 6 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 34551e4..c411c6b 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -899,8 +899,12 @@ enum bpf_cgroup_storage_type { /* The argument is a structure. */ #define BTF_FMODEL_STRUCT_ARG BIT(0) +/* The argument is signed. */ +#define BTF_FMODEL_SIGNED_ARG BIT(1) + struct btf_func_model { u8 ret_size; + u8 ret_flags; u8 nr_args; u8 arg_size[MAX_BPF_FUNC_ARGS]; u8 arg_flags[MAX_BPF_FUNC_ARGS]; diff --git a/include/linux/btf.h b/include/linux/btf.h index 5f628f3..e9b90d9 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -236,6 +236,16 @@ static inline bool btf_type_is_small_int(const struct btf_type *t) return btf_type_is_int(t) && t->size <= sizeof(u64); } +static inline u8 btf_int_encoding(const struct btf_type *t) +{ + return BTF_INT_ENCODING(*(u32 *)(t + 1)); +} + +static inline bool btf_type_is_signed_int(const struct btf_type *t) +{ + return btf_type_is_int(t) && (btf_int_encoding(t) & BTF_INT_SIGNED); +} + static inline bool btf_type_is_enum(const struct btf_type *t) { return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM; @@ -306,11 +316,6 @@ static inline u8 btf_int_offset(const struct btf_type *t) return BTF_INT_OFFSET(*(u32 *)(t + 1)); } -static inline u8 btf_int_encoding(const struct btf_type *t) -{ - return BTF_INT_ENCODING(*(u32 *)(t + 1)); -} - static inline bool btf_type_is_scalar(const struct btf_type *t) { return btf_type_is_int(t) || btf_type_is_enum(t); diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 47b8cb9..1622a3b 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6453,6 +6453,18 @@ static int __get_type_size(struct btf *btf, u32 btf_id, return -EINVAL; } +static u8 __get_type_fmodel_flags(const struct btf_type *t) +{ + u8 flags = 0; + + if (__btf_type_is_struct(t)) + flags |= BTF_FMODEL_STRUCT_ARG; + if (btf_type_is_signed_int(t)) + flags |= BTF_FMODEL_SIGNED_ARG; + + return flags; +} + int btf_distill_func_proto(struct bpf_verifier_log *log, struct btf *btf, const struct btf_type *func, @@ -6473,6 +6485,7 @@ int btf_distill_func_proto(struct bpf_verifier_log *log, m->arg_flags[i] = 0; } m->ret_size = 8; + m->ret_flags = 0; m->nr_args = MAX_BPF_FUNC_REG_ARGS; return 0; } @@ -6492,6 +6505,7 @@ int btf_distill_func_proto(struct bpf_verifier_log *log, return -EINVAL; } m->ret_size = ret; + m->ret_flags = __get_type_fmodel_flags(t); for (i = 0; i < nargs; i++) { if (i == nargs - 1 && args[i].type == 0) { @@ -6516,7 +6530,7 @@ int btf_distill_func_proto(struct bpf_verifier_log *log, return -EINVAL; } m->arg_size[i] = ret; - m->arg_flags[i] = __btf_type_is_struct(t) ? BTF_FMODEL_STRUCT_ARG : 0; + m->arg_flags[i] = __get_type_fmodel_flags(t); } m->nr_args = nargs; return 0; -- 2.7.4