diff mbox series

[bpf-next,v2,25/31] bpf: btf: Add BTF_FMODEL_SIGNED_ARG flag

Message ID 20230128000650.1516334-26-iii@linux.ibm.com (mailing list archive)
State Superseded
Commit 49f67f393ff264e8d83f6fcec0728a6aa8eed102
Delegated to: BPF
Headers show
Series Support bpf trampoline for s390x | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for bpf-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count fail Series longer than 15 patches (and no cover letter)
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1420 this patch: 1420
netdev/cc_maintainers warning 8 maintainers not CCed: sdf@google.com kpsingh@kernel.org jolsa@kernel.org martin.lau@linux.dev song@kernel.org john.fastabend@gmail.com haoluo@google.com yhs@fb.com
netdev/build_clang success Errors and warnings before: 149 this patch: 149
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1415 this patch: 1415
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 79 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-VM_Test-4 success Logs for build for s390x with gcc
bpf/vmtest-bpf-next-VM_Test-9 success Logs for test_maps on aarch64 with gcc
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Commit Message

Ilya Leoshkevich Jan. 28, 2023, 12:06 a.m. UTC 
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 mbox series

Patch

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;