From ca7e324e8ad385a2da15049953c04ea7310687f7 Mon Sep 17 00:00:00 2001
From: Alexander Lobakin <aleksander.lobakin@intel.com>
Date: Wed, 27 Mar 2024 15:22:39 +0100
Subject: [PATCH] compiler_types: add Endianness-dependent __counted_by_{le,be}
Some structures contain flexible arrays at the end and the counter for
them, but the counter has explicit Endianness and thus __counted_by()
can't be used directly.
To increase test coverage for potential problems without breaking
anything, introduce __counted_by_{le,be}() defined depending on
platform's Endianness to either __counted_by() when applicable or noop
otherwise.
Maybe it would be a good idea to introduce such attributes on compiler
level if possible, but for now let's stop on what we have.
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://lore.kernel.org/r/20240327142241.1745989-2-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
Documentation/conf.py | 2 ++
include/linux/compiler_types.h | 11 +++++++++++
scripts/kernel-doc | 1 +
3 files changed, 14 insertions(+)
diff --git a/Documentation/conf.py b/Documentation/conf.py
index d148f3e8dd572..0c2205d536b38 100644
--- a/Documentation/conf.py
+++ b/Documentation/conf.py
@@ -75,6 +75,8 @@ if major >= 3:
"__rcu",
"__user",
"__force",
+ "__counted_by_le",
+ "__counted_by_be",
# include/linux/compiler_attributes.h:
"__alias",
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index 2abaa3a825a9e..a29ba6ef1e275 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -282,6 +282,17 @@ struct ftrace_likely_data {
#define __no_sanitize_or_inline __always_inline
#endif
+/*
+ * Apply __counted_by() when the Endianness matches to increase test coverage.
+ */
+#ifdef __LITTLE_ENDIAN
+#define __counted_by_le(member) __counted_by(member)
+#define __counted_by_be(member)
+#else
+#define __counted_by_le(member)
+#define __counted_by_be(member) __counted_by(member)
+#endif
+
/* Do not trap wrapping arithmetic within an annotated function. */
#ifdef CONFIG_UBSAN_SIGNED_WRAP
# define __signed_wrap __attribute__((no_sanitize("signed-integer-overflow")))
diff --git a/scripts/kernel-doc b/scripts/kernel-doc
index 967f1abb0edbd..1474e95dbe4f0 100755
--- a/scripts/kernel-doc
+++ b/scripts/kernel-doc
@@ -1143,6 +1143,7 @@ sub dump_struct($$) {
$members =~ s/\s*$attribute/ /gi;
$members =~ s/\s*__aligned\s*\([^;]*\)/ /gos;
$members =~ s/\s*__counted_by\s*\([^;]*\)/ /gos;
+ $members =~ s/\s*__counted_by_(le|be)\s*\([^;]*\)/ /gos;
$members =~ s/\s*__packed\s*/ /gos;
$members =~ s/\s*CRYPTO_MINALIGN_ATTR/ /gos;
$members =~ s/\s*____cacheline_aligned_in_smp/ /gos;
--
2.30.2