From c0f8aa4fa815daacb6eca52cae04820d6aecb7c2 Mon Sep 17 00:00:00 2001 From: Daniel Axtens Date: Mon, 28 Jun 2021 19:40:46 -0700 Subject: [PATCH] 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 Acked-by: Andrey Konovalov Reviewed-by: Christophe Leroy Reviewed-by: Marco Elver Cc: Aneesh Kumar K.V Cc: Balbir Singh Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Dmitry Vyukov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/s390/include/asm/pgtable.h | 2 -- include/asm-generic/pgtable-nop4d.h | 1 - include/linux/pgtable.h | 22 ++++++++++++++++++++++ 3 files changed, 22 insertions(+), 3 deletions(-) diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 29c7ecd..b38f7b7 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -344,8 +344,6 @@ static inline int is_module_addr(void *addr) #define PTRS_PER_P4D _CRST_ENTRIES #define PTRS_PER_PGD _CRST_ENTRIES -#define MAX_PTRS_PER_P4D PTRS_PER_P4D - /* * Segment table and region3 table entry encoding * (R = read-only, I = invalid, y = young bit): diff --git a/include/asm-generic/pgtable-nop4d.h b/include/asm-generic/pgtable-nop4d.h index ce2cbb3..2f6b1be 100644 --- a/include/asm-generic/pgtable-nop4d.h +++ b/include/asm-generic/pgtable-nop4d.h @@ -9,7 +9,6 @@ typedef struct { pgd_t pgd; } p4d_t; #define P4D_SHIFT PGDIR_SHIFT -#define MAX_PTRS_PER_P4D 1 #define PTRS_PER_P4D 1 #define P4D_SIZE (1UL << P4D_SHIFT) #define P4D_MASK (~(P4D_SIZE-1)) diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index a43047b..c32600c 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 */ -- 2.7.4