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    SubjectRe: [PATCH v9 3/6] kasan: define and use MAX_PTRS_PER_* for early shadow tables
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    Le 01/12/2020 à 17:16, Daniel Axtens a écrit :
    > powerpc has a variable number of PTRS_PER_*, set at runtime based
    > on the MMU that the kernel is booted under.
    >
    > This means the PTRS_PER_* are no longer constants, and therefore
    > breaks the build.
    >
    > Define default MAX_PTRS_PER_*s in the same style as MAX_PTRS_PER_P4D.
    > As KASAN is the only user at the moment, just define them in the kasan
    > header, and have them default to PTRS_PER_* unless overridden in arch
    > code.
    >
    > Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>

    My neww address is : christophe.leroy@csgroup.eu

    > Suggested-by: Balbir Singh <bsingharora@gmail.com>
    > Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>

    Same

    > Reviewed-by: Balbir Singh <bsingharora@gmail.com>
    > Signed-off-by: Daniel Axtens <dja@axtens.net>
    > ---
    > include/linux/kasan.h | 18 +++++++++++++++---
    > mm/kasan/init.c | 6 +++---
    > 2 files changed, 18 insertions(+), 6 deletions(-)
    >
    > diff --git a/include/linux/kasan.h b/include/linux/kasan.h
    > index 3df66fdf6662..893d054aad6f 100644
    > --- a/include/linux/kasan.h
    > +++ b/include/linux/kasan.h
    > @@ -24,10 +24,22 @@ struct kunit_kasan_expectation {
    > static inline bool kasan_arch_is_ready(void) { return true; }
    > #endif
    >
    > +#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
    > +
    > extern unsigned char kasan_early_shadow_page[PAGE_SIZE];
    > -extern pte_t kasan_early_shadow_pte[PTRS_PER_PTE];
    > -extern pmd_t kasan_early_shadow_pmd[PTRS_PER_PMD];
    > -extern pud_t kasan_early_shadow_pud[PTRS_PER_PUD];
    > +extern pte_t kasan_early_shadow_pte[MAX_PTRS_PER_PTE];
    > +extern pmd_t kasan_early_shadow_pmd[MAX_PTRS_PER_PMD];
    > +extern pud_t kasan_early_shadow_pud[MAX_PTRS_PER_PUD];
    > extern p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D];
    >
    > int kasan_populate_early_shadow(const void *shadow_start,
    > diff --git a/mm/kasan/init.c b/mm/kasan/init.c
    > index fe6be0be1f76..42bca3d27db8 100644
    > --- a/mm/kasan/init.c
    > +++ b/mm/kasan/init.c
    > @@ -46,7 +46,7 @@ static inline bool kasan_p4d_table(pgd_t pgd)
    > }
    > #endif
    > #if CONFIG_PGTABLE_LEVELS > 3
    > -pud_t kasan_early_shadow_pud[PTRS_PER_PUD] __page_aligned_bss;
    > +pud_t kasan_early_shadow_pud[MAX_PTRS_PER_PUD] __page_aligned_bss;
    > static inline bool kasan_pud_table(p4d_t p4d)
    > {
    > return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud));
    > @@ -58,7 +58,7 @@ static inline bool kasan_pud_table(p4d_t p4d)
    > }
    > #endif
    > #if CONFIG_PGTABLE_LEVELS > 2
    > -pmd_t kasan_early_shadow_pmd[PTRS_PER_PMD] __page_aligned_bss;
    > +pmd_t kasan_early_shadow_pmd[MAX_PTRS_PER_PMD] __page_aligned_bss;
    > static inline bool kasan_pmd_table(pud_t pud)
    > {
    > return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd));
    > @@ -69,7 +69,7 @@ static inline bool kasan_pmd_table(pud_t pud)
    > return false;
    > }
    > #endif
    > -pte_t kasan_early_shadow_pte[PTRS_PER_PTE] __page_aligned_bss;
    > +pte_t kasan_early_shadow_pte[MAX_PTRS_PER_PTE] __page_aligned_bss;
    >
    > static inline bool kasan_pte_table(pmd_t pmd)
    > {
    >

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