From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> Subject: mm/mremap: allow arch runtime override Patch series "Speedup mremap on ppc64", v8. This patchset enables MOVE_PMD/MOVE_PUD support on power. This requires the platform to support updating higher-level page tables without updating page table entries. This also needs to invalidate the Page Walk Cache on architecture supporting the same. This patch (of 3): Architectures like ppc64 support faster mremap only with radix translation. Hence allow a runtime check w.r.t support for fast mremap. Link: https://lkml.kernel.org/r/20210616045735.374532-1-aneesh.kumar@xxxxxxxxxxxxx Link: https://lkml.kernel.org/r/20210616045735.374532-2-aneesh.kumar@xxxxxxxxxxxxx Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Kalesh Singh <kaleshsingh@xxxxxxxxxx> Cc: Nicholas Piggin <npiggin@xxxxxxxxx> Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx> Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx> Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> Cc: "Aneesh Kumar K . V" <aneesh.kumar@xxxxxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/powerpc/include/asm/tlb.h | 6 ++++++ mm/mremap.c | 15 ++++++++++++++- 2 files changed, 20 insertions(+), 1 deletion(-) --- a/arch/powerpc/include/asm/tlb.h~mm-mremap-allow-arch-runtime-override +++ a/arch/powerpc/include/asm/tlb.h @@ -83,5 +83,11 @@ static inline int mm_is_thread_local(str } #endif +#define arch_supports_page_table_move arch_supports_page_table_move +static inline bool arch_supports_page_table_move(void) +{ + return radix_enabled(); +} + #endif /* __KERNEL__ */ #endif /* __ASM_POWERPC_TLB_H */ --- a/mm/mremap.c~mm-mremap-allow-arch-runtime-override +++ a/mm/mremap.c @@ -25,7 +25,7 @@ #include <linux/userfaultfd_k.h> #include <asm/cacheflush.h> -#include <asm/tlbflush.h> +#include <asm/tlb.h> #include <asm/pgalloc.h> #include "internal.h" @@ -210,6 +210,15 @@ static void move_ptes(struct vm_area_str drop_rmap_locks(vma); } +#ifndef arch_supports_page_table_move +#define arch_supports_page_table_move arch_supports_page_table_move +static inline bool arch_supports_page_table_move(void) +{ + return IS_ENABLED(CONFIG_HAVE_MOVE_PMD) || + IS_ENABLED(CONFIG_HAVE_MOVE_PUD); +} +#endif + #ifdef CONFIG_HAVE_MOVE_PMD static bool move_normal_pmd(struct vm_area_struct *vma, unsigned long old_addr, unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) @@ -218,6 +227,8 @@ static bool move_normal_pmd(struct vm_ar struct mm_struct *mm = vma->vm_mm; pmd_t pmd; + if (!arch_supports_page_table_move()) + return false; /* * The destination pmd shouldn't be established, free_pgtables() * should have released it. @@ -284,6 +295,8 @@ static bool move_normal_pud(struct vm_ar struct mm_struct *mm = vma->vm_mm; pud_t pud; + if (!arch_supports_page_table_move()) + return false; /* * The destination pud shouldn't be established, free_pgtables() * should have released it. _
