From aeb9ce058d7c6193dc41e06b3a5b29d22c446b14 Mon Sep 17 00:00:00 2001 From: Coco Li Date: Wed, 29 Nov 2023 07:27:53 +0000 Subject: [PATCH] cache: enforce cache groups Set up build time warnings to safeguard against future header changes of organized structs. Warning includes: 1) whether all variables are still in the same cache group 2) whether all the cache groups have the sum of the members size (in the maximum condition, including all members defined in configs) The __cache_group* variables are ignored in kernel-doc check in the various header files they appear in to enforce the cache groups. Suggested-by: Daniel Borkmann Acked-by: Daniel Borkmann Signed-off-by: Coco Li Reviewed-by: Eric Dumazet Reviewed-by: Shakeel Butt Signed-off-by: David S. Miller --- include/linux/cache.h | 25 +++++++++++++++++++++++++ scripts/kernel-doc | 5 +++++ 2 files changed, 30 insertions(+) diff --git a/include/linux/cache.h b/include/linux/cache.h index 9900d20b76c2..0ecb17bb6883 100644 --- a/include/linux/cache.h +++ b/include/linux/cache.h @@ -85,6 +85,31 @@ #define cache_line_size() L1_CACHE_BYTES #endif +#ifndef __cacheline_group_begin +#define __cacheline_group_begin(GROUP) \ + __u8 __cacheline_group_begin__##GROUP[0] +#endif + +#ifndef __cacheline_group_end +#define __cacheline_group_end(GROUP) \ + __u8 __cacheline_group_end__##GROUP[0] +#endif + +#ifndef CACHELINE_ASSERT_GROUP_MEMBER +#define CACHELINE_ASSERT_GROUP_MEMBER(TYPE, GROUP, MEMBER) \ + BUILD_BUG_ON(!(offsetof(TYPE, MEMBER) >= \ + offsetofend(TYPE, __cacheline_group_begin__##GROUP) && \ + offsetofend(TYPE, MEMBER) <= \ + offsetof(TYPE, __cacheline_group_end__##GROUP))) +#endif + +#ifndef CACHELINE_ASSERT_GROUP_SIZE +#define CACHELINE_ASSERT_GROUP_SIZE(TYPE, GROUP, SIZE) \ + BUILD_BUG_ON(offsetof(TYPE, __cacheline_group_end__##GROUP) - \ + offsetofend(TYPE, __cacheline_group_begin__##GROUP) > \ + SIZE) +#endif + /* * Helper to add padding within a struct to ensure data fall into separate * cachelines. diff --git a/scripts/kernel-doc b/scripts/kernel-doc index 08a3e603db19..0a890fe4d22b 100755 --- a/scripts/kernel-doc +++ b/scripts/kernel-doc @@ -1592,6 +1592,11 @@ sub push_parameter($$$$$) { $parameterdescs{$param} = "anonymous\n"; $anon_struct_union = 1; } + elsif ($param =~ "__cacheline_group" ) + # handle cache group enforcing variables: they do not need be described in header files + { + return; # ignore __cacheline_group_begin and __cacheline_group_end + } # warn if parameter has no description # (but ignore ones starting with # as these are not parameters