From 298fa1ad5571f59cb3ca5497a9455f36867f065e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 3 Nov 2020 10:27:18 +0100 Subject: [PATCH] highmem: Provide generic variant of kmap_atomic* The kmap_atomic* interfaces in all architectures are pretty much the same except for post map operations (flush) and pre- and post unmap operations. Provide a generic variant for that. Signed-off-by: Thomas Gleixner Cc: Linus Torvalds Cc: Christoph Hellwig Cc: Andrew Morton Link: https://lore.kernel.org/r/20201103095857.175939340@linutronix.de --- include/linux/highmem.h | 82 ++++++++++++++++++----- mm/Kconfig | 3 + mm/highmem.c | 144 +++++++++++++++++++++++++++++++++++++++- 3 files changed, 211 insertions(+), 18 deletions(-) diff --git a/include/linux/highmem.h b/include/linux/highmem.h index f5c31338f0a3..f5ecee9c2576 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -31,9 +31,16 @@ static inline void invalidate_kernel_vmap_range(void *vaddr, int size) #include +/* + * Outside of CONFIG_HIGHMEM to support X86 32bit iomap_atomic() cruft. + */ +#ifdef CONFIG_KMAP_LOCAL +void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot); +void *__kmap_local_page_prot(struct page *page, pgprot_t prot); +void kunmap_local_indexed(void *vaddr); +#endif + #ifdef CONFIG_HIGHMEM -extern void *kmap_atomic_high_prot(struct page *page, pgprot_t prot); -extern void kunmap_atomic_high(void *kvaddr); #include #ifndef ARCH_HAS_KMAP_FLUSH_TLB @@ -81,6 +88,11 @@ static inline void kunmap(struct page *page) * be used in IRQ contexts, so in some (very limited) cases we need * it. */ + +#ifndef CONFIG_KMAP_LOCAL +void *kmap_atomic_high_prot(struct page *page, pgprot_t prot); +void kunmap_atomic_high(void *kvaddr); + static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot) { preempt_disable(); @@ -89,7 +101,38 @@ static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot) return page_address(page); return kmap_atomic_high_prot(page, prot); } -#define kmap_atomic(page) kmap_atomic_prot(page, kmap_prot) + +static inline void __kunmap_atomic(void *vaddr) +{ + kunmap_atomic_high(vaddr); +} +#else /* !CONFIG_KMAP_LOCAL */ + +static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot) +{ + preempt_disable(); + pagefault_disable(); + return __kmap_local_page_prot(page, prot); +} + +static inline void *kmap_atomic_pfn(unsigned long pfn) +{ + preempt_disable(); + pagefault_disable(); + return __kmap_local_pfn_prot(pfn, kmap_prot); +} + +static inline void __kunmap_atomic(void *addr) +{ + kunmap_local_indexed(addr); +} + +#endif /* CONFIG_KMAP_LOCAL */ + +static inline void *kmap_atomic(struct page *page) +{ + return kmap_atomic_prot(page, kmap_prot); +} /* declarations for linux/mm/highmem.c */ unsigned int nr_free_highpages(void); @@ -147,25 +190,33 @@ static inline void *kmap_atomic(struct page *page) pagefault_disable(); return page_address(page); } -#define kmap_atomic_prot(page, prot) kmap_atomic(page) -static inline void kunmap_atomic_high(void *addr) +static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot) +{ + return kmap_atomic(page); +} + +static inline void *kmap_atomic_pfn(unsigned long pfn) +{ + return kmap_atomic(pfn_to_page(pfn)); +} + +static inline void __kunmap_atomic(void *addr) { /* * Mostly nothing to do in the CONFIG_HIGHMEM=n case as kunmap_atomic() - * handles re-enabling faults + preemption + * handles re-enabling faults and preemption */ #ifdef ARCH_HAS_FLUSH_ON_KUNMAP kunmap_flush_on_unmap(addr); #endif } -#define kmap_atomic_pfn(pfn) kmap_atomic(pfn_to_page(pfn)) - #define kmap_flush_unused() do {} while(0) #endif /* CONFIG_HIGHMEM */ +#if !defined(CONFIG_KMAP_LOCAL) #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32) DECLARE_PER_CPU(int, __kmap_atomic_idx); @@ -196,22 +247,21 @@ static inline void kmap_atomic_idx_pop(void) __this_cpu_dec(__kmap_atomic_idx); #endif } - +#endif #endif /* * Prevent people trying to call kunmap_atomic() as if it were kunmap() * kunmap_atomic() should get the return value of kmap_atomic, not the page. */ -#define kunmap_atomic(addr) \ -do { \ - BUILD_BUG_ON(__same_type((addr), struct page *)); \ - kunmap_atomic_high(addr); \ - pagefault_enable(); \ - preempt_enable(); \ +#define kunmap_atomic(__addr) \ +do { \ + BUILD_BUG_ON(__same_type((__addr), struct page *)); \ + __kunmap_atomic(__addr); \ + pagefault_enable(); \ + preempt_enable(); \ } while (0) - /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */ #ifndef clear_user_highpage static inline void clear_user_highpage(struct page *page, unsigned long vaddr) diff --git a/mm/Kconfig b/mm/Kconfig index d42423f884a7..a1ccf98b7333 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -872,4 +872,7 @@ config ARCH_HAS_HUGEPD config MAPPING_DIRTY_HELPERS bool +config KMAP_LOCAL + bool + endmenu diff --git a/mm/highmem.c b/mm/highmem.c index 6abfd762eee7..bb4ce13ee7e7 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -31,9 +31,11 @@ #include #include +#ifndef CONFIG_KMAP_LOCAL #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32) DEFINE_PER_CPU(int, __kmap_atomic_idx); #endif +#endif /* * Virtual_count is not a pure "count". @@ -365,9 +367,147 @@ void kunmap_high(struct page *page) if (need_wakeup) wake_up(pkmap_map_wait); } - EXPORT_SYMBOL(kunmap_high); -#endif /* CONFIG_HIGHMEM */ +#endif /* CONFIG_HIGHMEM */ + +#ifdef CONFIG_KMAP_LOCAL + +#include + +static DEFINE_PER_CPU(int, __kmap_local_idx); + +static inline int kmap_local_idx_push(void) +{ + int idx = __this_cpu_inc_return(__kmap_local_idx) - 1; + + WARN_ON_ONCE(in_irq() && !irqs_disabled()); + BUG_ON(idx >= KM_MAX_IDX); + return idx; +} + +static inline int kmap_local_idx(void) +{ + return __this_cpu_read(__kmap_local_idx) - 1; +} + +static inline void kmap_local_idx_pop(void) +{ + int idx = __this_cpu_dec_return(__kmap_local_idx); + + BUG_ON(idx < 0); +} + +#ifndef arch_kmap_local_post_map +# define arch_kmap_local_post_map(vaddr, pteval) do { } while (0) +#endif +#ifndef arch_kmap_local_pre_unmap +# define arch_kmap_local_pre_unmap(vaddr) do { } while (0) +#endif + +#ifndef arch_kmap_local_post_unmap +# define arch_kmap_local_post_unmap(vaddr) do { } while (0) +#endif + +#ifndef arch_kmap_local_map_idx +#define arch_kmap_local_map_idx(idx, pfn) kmap_local_calc_idx(idx) +#endif + +#ifndef arch_kmap_local_unmap_idx +#define arch_kmap_local_unmap_idx(idx, vaddr) kmap_local_calc_idx(idx) +#endif + +#ifndef arch_kmap_local_high_get +static inline void *arch_kmap_local_high_get(struct page *page) +{ + return NULL; +} +#endif + +/* Unmap a local mapping which was obtained by kmap_high_get() */ +static inline void kmap_high_unmap_local(unsigned long vaddr) +{ +#ifdef ARCH_NEEDS_KMAP_HIGH_GET + if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) + kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)])); +#endif +} + +static inline int kmap_local_calc_idx(int idx) +{ + return idx + KM_MAX_IDX * smp_processor_id(); +} + +static pte_t *__kmap_pte; + +static pte_t *kmap_get_pte(void) +{ + if (!__kmap_pte) + __kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN)); + return __kmap_pte; +} + +void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot) +{ + pte_t pteval, *kmap_pte = kmap_get_pte(); + unsigned long vaddr; + int idx; + + preempt_disable(); + idx = arch_kmap_local_map_idx(kmap_local_idx_push(), pfn); + vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); + BUG_ON(!pte_none(*(kmap_pte - idx))); + pteval = pfn_pte(pfn, prot); + set_pte_at(&init_mm, vaddr, kmap_pte - idx, pteval); + arch_kmap_local_post_map(vaddr, pteval); + preempt_enable(); + + return (void *)vaddr; +} +EXPORT_SYMBOL_GPL(__kmap_local_pfn_prot); + +void *__kmap_local_page_prot(struct page *page, pgprot_t prot) +{ + void *kmap; + + if (!PageHighMem(page)) + return page_address(page); + + /* Try kmap_high_get() if architecture has it enabled */ + kmap = arch_kmap_local_high_get(page); + if (kmap) + return kmap; + + return __kmap_local_pfn_prot(page_to_pfn(page), prot); +} +EXPORT_SYMBOL(__kmap_local_page_prot); + +void kunmap_local_indexed(void *vaddr) +{ + unsigned long addr = (unsigned long) vaddr & PAGE_MASK; + pte_t *kmap_pte = kmap_get_pte(); + int idx; + + if (addr < __fix_to_virt(FIX_KMAP_END) || + addr > __fix_to_virt(FIX_KMAP_BEGIN)) { + WARN_ON_ONCE(addr < PAGE_OFFSET); + + /* Handle mappings which were obtained by kmap_high_get() */ + kmap_high_unmap_local(addr); + return; + } + + preempt_disable(); + idx = arch_kmap_local_unmap_idx(kmap_local_idx(), addr); + WARN_ON_ONCE(addr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); + + arch_kmap_local_pre_unmap(addr); + pte_clear(&init_mm, addr, kmap_pte - idx); + arch_kmap_local_post_unmap(addr); + kmap_local_idx_pop(); + preempt_enable(); +} +EXPORT_SYMBOL(kunmap_local_indexed); +#endif #if defined(HASHED_PAGE_VIRTUAL)