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From: Ilya Leoshkevich <iii@linux.ibm.com>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH bpf-next v2 25/31] bpf: btf: Add BTF_FMODEL_SIGNED_ARG flag
Date: Sat, 28 Jan 2023 01:06:44 +0100	[thread overview]
Message-ID: <20230128000650.1516334-26-iii@linux.ibm.com> (raw)
In-Reply-To: <20230128000650.1516334-1-iii@linux.ibm.com>

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 <iii@linux.ibm.com>
---
 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 6415b54fea4e..8aafbe6af21c 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 5f628f323442..e9b90d9c3569 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 47b8cb96f2c2..1622a3b15d6f 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;
-- 
2.39.1


  parent reply	other threads:[~2023-01-28  0:08 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-28  0:06 [PATCH bpf-next v2 00/31] Support bpf trampoline for s390x Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 01/31] bpf: Use ARG_CONST_SIZE_OR_ZERO for 3rd argument of bpf_tcp_raw_gen_syncookie_ipv{4,6}() Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 02/31] bpf: Change BPF_MAX_TRAMP_LINKS to enum Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 03/31] selftests/bpf: Query BPF_MAX_TRAMP_LINKS using BTF Ilya Leoshkevich
2023-01-28 20:49   ` Alexei Starovoitov
2023-01-29  1:50     ` Alexei Starovoitov
2023-01-28  0:06 ` [PATCH bpf-next v2 04/31] selftests/bpf: Fix liburandom_read.so linker error Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 05/31] selftests/bpf: Fix symlink creation error Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 06/31] selftests/bpf: Fix kfree_skb on s390x Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 07/31] selftests/bpf: Set errno when urand_spawn() fails Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 08/31] selftests/bpf: Fix decap_sanity_ns cleanup Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 09/31] selftests/bpf: Fix verify_pkcs7_sig on s390x Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 10/31] selftests/bpf: Fix xdp_do_redirect " Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 11/31] selftests/bpf: Fix cgrp_local_storage " Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 12/31] selftests/bpf: Check stack_mprotect() return value Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 13/31] selftests/bpf: Increase SIZEOF_BPF_LOCAL_STORAGE_ELEM on s390x Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 14/31] selftests/bpf: Add a sign-extension test for kfuncs Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 15/31] selftests/bpf: Fix test_lsm on s390x Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 16/31] selftests/bpf: Fix test_xdp_adjust_tail_grow2 " Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 17/31] selftests/bpf: Fix vmlinux test " Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 18/31] selftests/bpf: Fix sk_assign " Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 19/31] selftests/bpf: Fix xdp_synproxy/tc " Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 20/31] selftests/bpf: Fix profiler " Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 21/31] libbpf: Simplify barrier_var() Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 22/31] libbpf: Fix unbounded memory access in bpf_usdt_arg() Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 23/31] libbpf: Fix BPF_PROBE_READ{_STR}_INTO() on s390x Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 24/31] bpf: iterators: Split iterators.lskel.h into little- and big- endian versions Ilya Leoshkevich
2023-01-28  0:06 ` Ilya Leoshkevich [this message]
2023-01-28  0:06 ` [PATCH bpf-next v2 26/31] s390/bpf: Fix a typo in a comment Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 27/31] s390/bpf: Add expoline to tail calls Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 28/31] s390/bpf: Implement bpf_arch_text_poke() Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 29/31] s390/bpf: Implement arch_prepare_bpf_trampoline() Ilya Leoshkevich
2023-01-28  8:37   ` kernel test robot
2023-01-28  0:06 ` [PATCH bpf-next v2 30/31] s390/bpf: Implement bpf_jit_supports_subprog_tailcalls() Ilya Leoshkevich
2023-01-28  0:06 ` [PATCH bpf-next v2 31/31] s390/bpf: Implement bpf_jit_supports_kfunc_call() Ilya Leoshkevich
2023-01-28 20:50 ` [PATCH bpf-next v2 00/31] Support bpf trampoline for s390x patchwork-bot+netdevbpf

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