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authorDaniel Axtens <dja@axtens.net>2021-06-29 05:40:46 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-06-29 20:53:53 +0300
commitc0f8aa4fa815daacb6eca52cae04820d6aecb7c2 (patch)
tree2484107da350ea1c6d4e77ec5c2b88d59c692b6f /include/linux/pgtable.h
parentaf3751f3c2b6282bebcb56c35bbe4c8b671f80aa (diff)
downloadlinux-c0f8aa4fa815daacb6eca52cae04820d6aecb7c2.tar.xz
mm: define default MAX_PTRS_PER_* in include/pgtable.h
Commit c65e774fb3f6 ("x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable") made PTRS_PER_P4D variable on x86 and introduced MAX_PTRS_PER_P4D as a constant for cases which need a compile-time constant (e.g. fixed-size arrays). powerpc likewise has boot-time selectable MMU features which can cause other mm "constants" to vary. For KASAN, we have some static PTE/PMD/PUD/P4D arrays so we need compile-time maximums for all these constants. Extend the MAX_PTRS_PER_ idiom, and place default definitions in include/pgtable.h. These define MAX_PTRS_PER_x to be PTRS_PER_x unless an architecture has defined MAX_PTRS_PER_x in its arch headers. Clean up pgtable-nop4d.h and s390's MAX_PTRS_PER_P4D definitions while we're at it: both can just pick up the default now. Link: https://lkml.kernel.org/r/20210624034050.511391-4-dja@axtens.net Signed-off-by: Daniel Axtens <dja@axtens.net> Acked-by: Andrey Konovalov <andreyknvl@gmail.com> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Marco Elver <elver@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/pgtable.h')
-rw-r--r--include/linux/pgtable.h22
1 files changed, 22 insertions, 0 deletions
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index a43047b1030d..c32600c9e1ad 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1592,4 +1592,26 @@ typedef unsigned int pgtbl_mod_mask;
#define pte_leaf_size(x) PAGE_SIZE
#endif
+/*
+ * Some architectures have MMUs that are configurable or selectable at boot
+ * time. These lead to variable PTRS_PER_x. For statically allocated arrays it
+ * helps to have a static maximum value.
+ */
+
+#ifndef MAX_PTRS_PER_PTE
+#define MAX_PTRS_PER_PTE PTRS_PER_PTE
+#endif
+
+#ifndef MAX_PTRS_PER_PMD
+#define MAX_PTRS_PER_PMD PTRS_PER_PMD
+#endif
+
+#ifndef MAX_PTRS_PER_PUD
+#define MAX_PTRS_PER_PUD PTRS_PER_PUD
+#endif
+
+#ifndef MAX_PTRS_PER_P4D
+#define MAX_PTRS_PER_P4D PTRS_PER_P4D
+#endif
+
#endif /* _LINUX_PGTABLE_H */