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authorPeter Zijlstra <peterz@infradead.org>2022-05-17 13:46:54 +0200
committerPeter Zijlstra <peterz@infradead.org>2022-05-19 23:46:13 +0200
commit546a3fee174969ff323d70ff27b1ef181f0d7ceb (patch)
tree35b15b82da76831919f3d48539f0c7c2b1d3882d /kernel/sched/sched.h
parentsched/deadline: Remove superfluous rq clock update in push_dl_task() (diff)
downloadlinux-dev-546a3fee174969ff323d70ff27b1ef181f0d7ceb.tar.xz
linux-dev-546a3fee174969ff323d70ff27b1ef181f0d7ceb.zip
sched: Reverse sched_class layout
Because GCC-12 is fully stupid about array bounds and it's just really hard to get a solid array definition from a linker script, flip the array order to avoid needing negative offsets :-/ This makes the whole relational pointer magic a little less obvious, but alas. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/YoOLLmLG7HRTXeEm@hirez.programming.kicks-ass.net
Diffstat (limited to 'kernel/sched/sched.h')
-rw-r--r--kernel/sched/sched.h15
1 files changed, 8 insertions, 7 deletions
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index fe4d1acb7e38..2ce18584dca3 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2177,6 +2177,8 @@ static inline void set_next_task(struct rq *rq, struct task_struct *next)
*
* include/asm-generic/vmlinux.lds.h
*
+ * *CAREFUL* they are laid out in *REVERSE* order!!!
+ *
* Also enforce alignment on the instance, not the type, to guarantee layout.
*/
#define DEFINE_SCHED_CLASS(name) \
@@ -2185,17 +2187,16 @@ const struct sched_class name##_sched_class \
__section("__" #name "_sched_class")
/* Defined in include/asm-generic/vmlinux.lds.h */
-extern struct sched_class __begin_sched_classes[];
-extern struct sched_class __end_sched_classes[];
-
-#define sched_class_highest (__end_sched_classes - 1)
-#define sched_class_lowest (__begin_sched_classes - 1)
+extern struct sched_class __sched_class_highest[];
+extern struct sched_class __sched_class_lowest[];
#define for_class_range(class, _from, _to) \
- for (class = (_from); class != (_to); class--)
+ for (class = (_from); class < (_to); class++)
#define for_each_class(class) \
- for_class_range(class, sched_class_highest, sched_class_lowest)
+ for_class_range(class, __sched_class_highest, __sched_class_lowest)
+
+#define sched_class_above(_a, _b) ((_a) < (_b))
extern const struct sched_class stop_sched_class;
extern const struct sched_class dl_sched_class;