From b819fd9da38508e0504624b87d9983fcc4237f3c Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 3 Nov 2020 10:27:14 +0100 Subject: highmem: Remove unused functions Nothing uses totalhigh_pages_dec() and totalhigh_pages_set(). Signed-off-by: Thomas Gleixner Cc: Christoph Hellwig Cc: Andrew Morton Link: https://lore.kernel.org/r/20201103095856.732891880@linutronix.de --- include/linux/highmem.h | 10 ---------- 1 file changed, 10 deletions(-) (limited to 'include/linux') diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 14e6202ce47f..f5c31338f0a3 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -104,21 +104,11 @@ static inline void totalhigh_pages_inc(void) atomic_long_inc(&_totalhigh_pages); } -static inline void totalhigh_pages_dec(void) -{ - atomic_long_dec(&_totalhigh_pages); -} - static inline void totalhigh_pages_add(long count) { atomic_long_add(count, &_totalhigh_pages); } -static inline void totalhigh_pages_set(long val) -{ - atomic_long_set(&_totalhigh_pages, val); -} - void kmap_flush_unused(void); struct page *kmap_to_page(void *addr); -- cgit v1.2.3 From 298fa1ad5571f59cb3ca5497a9455f36867f065e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 3 Nov 2020 10:27:18 +0100 Subject: 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(-) (limited to 'include/linux') 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) -- cgit v1.2.3 From 157e118b55113d1e6c7f8ddfcec0a1dbf3a69511 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 3 Nov 2020 10:27:20 +0100 Subject: x86/mm/highmem: Use generic kmap atomic implementation Convert X86 to the generic kmap atomic implementation and make the iomap_atomic() naming convention consistent while at it. Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20201103095857.375127260@linutronix.de --- arch/x86/Kconfig | 3 +- arch/x86/include/asm/fixmap.h | 5 ++- arch/x86/include/asm/highmem.h | 13 +++++--- arch/x86/include/asm/iomap.h | 18 ++++++----- arch/x86/include/asm/kmap_types.h | 13 -------- arch/x86/include/asm/paravirt_types.h | 1 - arch/x86/mm/highmem_32.c | 59 ----------------------------------- arch/x86/mm/init_32.c | 15 --------- arch/x86/mm/iomap_32.c | 59 +++-------------------------------- include/linux/highmem.h | 2 +- include/linux/io-mapping.h | 2 +- mm/highmem.c | 2 +- 12 files changed, 31 insertions(+), 161 deletions(-) delete mode 100644 arch/x86/include/asm/kmap_types.h (limited to 'include/linux') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index f6946b81f74a..33c273cb3023 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -14,10 +14,11 @@ config X86_32 select ARCH_WANT_IPC_PARSE_VERSION select CLKSRC_I8253 select CLONE_BACKWARDS + select GENERIC_VDSO_32 select HAVE_DEBUG_STACKOVERFLOW + select KMAP_LOCAL select MODULES_USE_ELF_REL select OLD_SIGACTION - select GENERIC_VDSO_32 config X86_64 def_bool y diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index 77217bd292bd..8eba66a33e39 100644 --- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -31,7 +31,7 @@ #include #ifdef CONFIG_X86_32 #include -#include +#include #else #include #endif @@ -94,7 +94,7 @@ enum fixed_addresses { #endif #ifdef CONFIG_X86_32 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */ - FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1, + FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1, #ifdef CONFIG_PCI_MMCONFIG FIX_PCIE_MCFG, #endif @@ -151,7 +151,6 @@ extern void reserve_top_address(unsigned long reserve); extern int fixmaps_set; -extern pte_t *kmap_pte; extern pte_t *pkmap_page_table; void __native_set_fixmap(enum fixed_addresses idx, pte_t pte); diff --git a/arch/x86/include/asm/highmem.h b/arch/x86/include/asm/highmem.h index 0f420b24e0fc..032e020853aa 100644 --- a/arch/x86/include/asm/highmem.h +++ b/arch/x86/include/asm/highmem.h @@ -23,7 +23,6 @@ #include #include -#include #include #include #include @@ -58,11 +57,17 @@ extern unsigned long highstart_pfn, highend_pfn; #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT) #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) -void *kmap_atomic_pfn(unsigned long pfn); -void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot); - #define flush_cache_kmaps() do { } while (0) +#define arch_kmap_local_post_map(vaddr, pteval) \ + arch_flush_lazy_mmu_mode() + +#define arch_kmap_local_post_unmap(vaddr) \ + do { \ + flush_tlb_one_kernel((vaddr)); \ + arch_flush_lazy_mmu_mode(); \ + } while (0) + extern void add_highpages_with_active_regions(int nid, unsigned long start_pfn, unsigned long end_pfn); diff --git a/arch/x86/include/asm/iomap.h b/arch/x86/include/asm/iomap.h index bacf68c4d70e..0be7a30fd6bc 100644 --- a/arch/x86/include/asm/iomap.h +++ b/arch/x86/include/asm/iomap.h @@ -9,19 +9,21 @@ #include #include #include +#include #include #include -void __iomem * -iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot); +void __iomem *iomap_atomic_pfn_prot(unsigned long pfn, pgprot_t prot); -void -iounmap_atomic(void __iomem *kvaddr); +static inline void iounmap_atomic(void __iomem *vaddr) +{ + kunmap_local_indexed((void __force *)vaddr); + pagefault_enable(); + preempt_enable(); +} -int -iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot); +int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot); -void -iomap_free(resource_size_t base, unsigned long size); +void iomap_free(resource_size_t base, unsigned long size); #endif /* _ASM_X86_IOMAP_H */ diff --git a/arch/x86/include/asm/kmap_types.h b/arch/x86/include/asm/kmap_types.h deleted file mode 100644 index 04ab8266e347..000000000000 --- a/arch/x86/include/asm/kmap_types.h +++ /dev/null @@ -1,13 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _ASM_X86_KMAP_TYPES_H -#define _ASM_X86_KMAP_TYPES_H - -#if defined(CONFIG_X86_32) && defined(CONFIG_DEBUG_HIGHMEM) -#define __WITH_KM_FENCE -#endif - -#include - -#undef __WITH_KM_FENCE - -#endif /* _ASM_X86_KMAP_TYPES_H */ diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 0fad9f61c76a..b6b02b7c19cc 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -41,7 +41,6 @@ #ifndef __ASSEMBLY__ #include -#include #include #include diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c index 075fe51317b0..2c54b76d8f84 100644 --- a/arch/x86/mm/highmem_32.c +++ b/arch/x86/mm/highmem_32.c @@ -4,65 +4,6 @@ #include /* for totalram_pages */ #include -void *kmap_atomic_high_prot(struct page *page, pgprot_t prot) -{ - unsigned long vaddr; - int idx, type; - - type = kmap_atomic_idx_push(); - idx = type + KM_TYPE_NR*smp_processor_id(); - vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); - BUG_ON(!pte_none(*(kmap_pte-idx))); - set_pte(kmap_pte-idx, mk_pte(page, prot)); - arch_flush_lazy_mmu_mode(); - - return (void *)vaddr; -} -EXPORT_SYMBOL(kmap_atomic_high_prot); - -/* - * This is the same as kmap_atomic() but can map memory that doesn't - * have a struct page associated with it. - */ -void *kmap_atomic_pfn(unsigned long pfn) -{ - return kmap_atomic_prot_pfn(pfn, kmap_prot); -} -EXPORT_SYMBOL_GPL(kmap_atomic_pfn); - -void kunmap_atomic_high(void *kvaddr) -{ - unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; - - if (vaddr >= __fix_to_virt(FIX_KMAP_END) && - vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) { - int idx, type; - - type = kmap_atomic_idx(); - idx = type + KM_TYPE_NR * smp_processor_id(); - -#ifdef CONFIG_DEBUG_HIGHMEM - WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); -#endif - /* - * Force other mappings to Oops if they'll try to access this - * pte without first remap it. Keeping stale mappings around - * is a bad idea also, in case the page changes cacheability - * attributes or becomes a protected page in a hypervisor. - */ - kpte_clear_flush(kmap_pte-idx, vaddr); - kmap_atomic_idx_pop(); - arch_flush_lazy_mmu_mode(); - } -#ifdef CONFIG_DEBUG_HIGHMEM - else { - BUG_ON(vaddr < PAGE_OFFSET); - BUG_ON(vaddr >= (unsigned long)high_memory); - } -#endif -} -EXPORT_SYMBOL(kunmap_atomic_high); - void __init set_highmem_pages_init(void) { struct zone *zone; diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c index 7c055259de3a..da31c2635ee4 100644 --- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c @@ -394,19 +394,6 @@ repeat: return last_map_addr; } -pte_t *kmap_pte; - -static void __init kmap_init(void) -{ - unsigned long kmap_vstart; - - /* - * Cache the first kmap pte: - */ - kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); - kmap_pte = virt_to_kpte(kmap_vstart); -} - #ifdef CONFIG_HIGHMEM static void __init permanent_kmaps_init(pgd_t *pgd_base) { @@ -712,8 +699,6 @@ void __init paging_init(void) __flush_tlb_all(); - kmap_init(); - /* * NOTE: at this point the bootmem allocator is fully available. */ diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c index f60398aeb644..e0a40d7cc66c 100644 --- a/arch/x86/mm/iomap_32.c +++ b/arch/x86/mm/iomap_32.c @@ -44,28 +44,7 @@ void iomap_free(resource_size_t base, unsigned long size) } EXPORT_SYMBOL_GPL(iomap_free); -void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot) -{ - unsigned long vaddr; - int idx, type; - - preempt_disable(); - pagefault_disable(); - - type = kmap_atomic_idx_push(); - idx = type + KM_TYPE_NR * smp_processor_id(); - vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); - set_pte(kmap_pte - idx, pfn_pte(pfn, prot)); - arch_flush_lazy_mmu_mode(); - - return (void *)vaddr; -} - -/* - * Map 'pfn' using protections 'prot' - */ -void __iomem * -iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot) +void __iomem *iomap_atomic_pfn_prot(unsigned long pfn, pgprot_t prot) { /* * For non-PAT systems, translate non-WB request to UC- just in @@ -81,36 +60,8 @@ iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot) /* Filter out unsupported __PAGE_KERNEL* bits: */ pgprot_val(prot) &= __default_kernel_pte_mask; - return (void __force __iomem *) kmap_atomic_prot_pfn(pfn, prot); -} -EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn); - -void -iounmap_atomic(void __iomem *kvaddr) -{ - unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; - - if (vaddr >= __fix_to_virt(FIX_KMAP_END) && - vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) { - int idx, type; - - type = kmap_atomic_idx(); - idx = type + KM_TYPE_NR * smp_processor_id(); - -#ifdef CONFIG_DEBUG_HIGHMEM - WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); -#endif - /* - * Force other mappings to Oops if they'll try to access this - * pte without first remap it. Keeping stale mappings around - * is a bad idea also, in case the page changes cacheability - * attributes or becomes a protected page in a hypervisor. - */ - kpte_clear_flush(kmap_pte-idx, vaddr); - kmap_atomic_idx_pop(); - } - - pagefault_enable(); - preempt_enable(); + preempt_disable(); + pagefault_disable(); + return (void __force __iomem *)__kmap_local_pfn_prot(pfn, prot); } -EXPORT_SYMBOL_GPL(iounmap_atomic); +EXPORT_SYMBOL_GPL(iomap_atomic_pfn_prot); diff --git a/include/linux/highmem.h b/include/linux/highmem.h index f5ecee9c2576..1222a31be842 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -217,7 +217,7 @@ static inline void __kunmap_atomic(void *addr) #endif /* CONFIG_HIGHMEM */ #if !defined(CONFIG_KMAP_LOCAL) -#if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32) +#if defined(CONFIG_HIGHMEM) DECLARE_PER_CPU(int, __kmap_atomic_idx); diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h index c75e4d3d8833..3b0940be72e9 100644 --- a/include/linux/io-mapping.h +++ b/include/linux/io-mapping.h @@ -69,7 +69,7 @@ io_mapping_map_atomic_wc(struct io_mapping *mapping, BUG_ON(offset >= mapping->size); phys_addr = mapping->base + offset; - return iomap_atomic_prot_pfn(PHYS_PFN(phys_addr), mapping->prot); + return iomap_atomic_pfn_prot(PHYS_PFN(phys_addr), mapping->prot); } static inline void diff --git a/mm/highmem.c b/mm/highmem.c index 67d2d5983cb0..77677c6844f7 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -32,7 +32,7 @@ #include #ifndef CONFIG_KMAP_LOCAL -#if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32) +#ifdef CONFIG_HIGHMEM DEFINE_PER_CPU(int, __kmap_atomic_idx); #endif #endif -- cgit v1.2.3 From d7029e4549691ecaf1ead536d3322a00bda85659 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 3 Nov 2020 10:27:30 +0100 Subject: highmem: Get rid of kmap_types.h The header is not longer used and on alpha, ia64, openrisc, parisc and um it was completely unused anyway as these architectures have no highmem support. Signed-off-by: Thomas Gleixner Cc: Christoph Hellwig Cc: Andrew Morton Cc: Arnd Bergmann Link: https://lore.kernel.org/r/20201103095858.422094352@linutronix.de --- arch/alpha/include/asm/kmap_types.h | 15 --------------- arch/ia64/include/asm/kmap_types.h | 13 ------------- arch/openrisc/mm/init.c | 1 - arch/openrisc/mm/ioremap.c | 1 - arch/parisc/include/asm/kmap_types.h | 13 ------------- arch/um/include/asm/fixmap.h | 1 - arch/um/include/asm/kmap_types.h | 13 ------------- include/asm-generic/Kbuild | 1 - include/asm-generic/kmap_types.h | 11 ----------- include/linux/highmem.h | 2 -- 10 files changed, 71 deletions(-) delete mode 100644 arch/alpha/include/asm/kmap_types.h delete mode 100644 arch/ia64/include/asm/kmap_types.h delete mode 100644 arch/parisc/include/asm/kmap_types.h delete mode 100644 arch/um/include/asm/kmap_types.h delete mode 100644 include/asm-generic/kmap_types.h (limited to 'include/linux') diff --git a/arch/alpha/include/asm/kmap_types.h b/arch/alpha/include/asm/kmap_types.h deleted file mode 100644 index 651714b45729..000000000000 --- a/arch/alpha/include/asm/kmap_types.h +++ /dev/null @@ -1,15 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _ASM_KMAP_TYPES_H -#define _ASM_KMAP_TYPES_H - -/* Dummy header just to define km_type. */ - -#ifdef CONFIG_DEBUG_HIGHMEM -#define __WITH_KM_FENCE -#endif - -#include - -#undef __WITH_KM_FENCE - -#endif diff --git a/arch/ia64/include/asm/kmap_types.h b/arch/ia64/include/asm/kmap_types.h deleted file mode 100644 index 5c268cf7c2bd..000000000000 --- a/arch/ia64/include/asm/kmap_types.h +++ /dev/null @@ -1,13 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _ASM_IA64_KMAP_TYPES_H -#define _ASM_IA64_KMAP_TYPES_H - -#ifdef CONFIG_DEBUG_HIGHMEM -#define __WITH_KM_FENCE -#endif - -#include - -#undef __WITH_KM_FENCE - -#endif /* _ASM_IA64_KMAP_TYPES_H */ diff --git a/arch/openrisc/mm/init.c b/arch/openrisc/mm/init.c index 8348feaaf46e..bf9b2310fc93 100644 --- a/arch/openrisc/mm/init.c +++ b/arch/openrisc/mm/init.c @@ -33,7 +33,6 @@ #include #include #include -#include #include #include #include diff --git a/arch/openrisc/mm/ioremap.c b/arch/openrisc/mm/ioremap.c index a978590d802d..5aed97a18bac 100644 --- a/arch/openrisc/mm/ioremap.c +++ b/arch/openrisc/mm/ioremap.c @@ -15,7 +15,6 @@ #include #include #include -#include #include #include #include diff --git a/arch/parisc/include/asm/kmap_types.h b/arch/parisc/include/asm/kmap_types.h deleted file mode 100644 index 3e70b5cd1123..000000000000 --- a/arch/parisc/include/asm/kmap_types.h +++ /dev/null @@ -1,13 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _ASM_KMAP_TYPES_H -#define _ASM_KMAP_TYPES_H - -#ifdef CONFIG_DEBUG_HIGHMEM -#define __WITH_KM_FENCE -#endif - -#include - -#undef __WITH_KM_FENCE - -#endif diff --git a/arch/um/include/asm/fixmap.h b/arch/um/include/asm/fixmap.h index 2c697a145ac1..2efac5827188 100644 --- a/arch/um/include/asm/fixmap.h +++ b/arch/um/include/asm/fixmap.h @@ -3,7 +3,6 @@ #define __UM_FIXMAP_H #include -#include #include #include #include diff --git a/arch/um/include/asm/kmap_types.h b/arch/um/include/asm/kmap_types.h deleted file mode 100644 index b0bd12de1d23..000000000000 --- a/arch/um/include/asm/kmap_types.h +++ /dev/null @@ -1,13 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -/* - * Copyright (C) 2002 Jeff Dike (jdike@karaya.com) - */ - -#ifndef __UM_KMAP_TYPES_H -#define __UM_KMAP_TYPES_H - -/* No more #include "asm/arch/kmap_types.h" ! */ - -#define KM_TYPE_NR 14 - -#endif diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild index ed62d384fb79..4365b9aa3e3f 100644 --- a/include/asm-generic/Kbuild +++ b/include/asm-generic/Kbuild @@ -30,7 +30,6 @@ mandatory-y += irq.h mandatory-y += irq_regs.h mandatory-y += irq_work.h mandatory-y += kdebug.h -mandatory-y += kmap_types.h mandatory-y += kmap_size.h mandatory-y += kprobes.h mandatory-y += linkage.h diff --git a/include/asm-generic/kmap_types.h b/include/asm-generic/kmap_types.h deleted file mode 100644 index 9f95b7b63d19..000000000000 --- a/include/asm-generic/kmap_types.h +++ /dev/null @@ -1,11 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _ASM_GENERIC_KMAP_TYPES_H -#define _ASM_GENERIC_KMAP_TYPES_H - -#ifdef __WITH_KM_FENCE -# define KM_TYPE_NR 41 -#else -# define KM_TYPE_NR 20 -#endif - -#endif diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 1222a31be842..de78869454b1 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -29,8 +29,6 @@ static inline void invalidate_kernel_vmap_range(void *vaddr, int size) } #endif -#include - /* * Outside of CONFIG_HIGHMEM to support X86 32bit iomap_atomic() cruft. */ -- cgit v1.2.3 From 3c1016b53c311906878c703af1e2b29855a9a962 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 3 Nov 2020 10:27:31 +0100 Subject: mm/highmem: Remove the old kmap_atomic cruft All users gone. Signed-off-by: Thomas Gleixner Cc: Linus Torvalds Cc: Christoph Hellwig Cc: Andrew Morton Cc: Arnd Bergmann Link: https://lore.kernel.org/r/20201103095858.516281567@linutronix.de --- include/linux/highmem.h | 63 ++++--------------------------------------------- mm/highmem.c | 7 +----- 2 files changed, 5 insertions(+), 65 deletions(-) (limited to 'include/linux') diff --git a/include/linux/highmem.h b/include/linux/highmem.h index de78869454b1..3180a8f7307f 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -86,31 +86,16 @@ 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(); pagefault_disable(); - if (!PageHighMem(page)) - return page_address(page); - return kmap_atomic_high_prot(page, prot); -} - -static inline void __kunmap_atomic(void *vaddr) -{ - kunmap_atomic_high(vaddr); + return __kmap_local_page_prot(page, prot); } -#else /* !CONFIG_KMAP_LOCAL */ -static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot) +static inline void *kmap_atomic(struct page *page) { - preempt_disable(); - pagefault_disable(); - return __kmap_local_page_prot(page, prot); + return kmap_atomic_prot(page, kmap_prot); } static inline void *kmap_atomic_pfn(unsigned long pfn) @@ -125,13 +110,6 @@ 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); extern atomic_long_t _totalhigh_pages; @@ -212,41 +190,8 @@ static inline void __kunmap_atomic(void *addr) #define kmap_flush_unused() do {} while(0) -#endif /* CONFIG_HIGHMEM */ - -#if !defined(CONFIG_KMAP_LOCAL) -#if defined(CONFIG_HIGHMEM) - -DECLARE_PER_CPU(int, __kmap_atomic_idx); - -static inline int kmap_atomic_idx_push(void) -{ - int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1; - -#ifdef CONFIG_DEBUG_HIGHMEM - WARN_ON_ONCE(in_irq() && !irqs_disabled()); - BUG_ON(idx >= KM_TYPE_NR); -#endif - return idx; -} - -static inline int kmap_atomic_idx(void) -{ - return __this_cpu_read(__kmap_atomic_idx) - 1; -} -static inline void kmap_atomic_idx_pop(void) -{ -#ifdef CONFIG_DEBUG_HIGHMEM - int idx = __this_cpu_dec_return(__kmap_atomic_idx); - - BUG_ON(idx < 0); -#else - __this_cpu_dec(__kmap_atomic_idx); -#endif -} -#endif -#endif +#endif /* CONFIG_HIGHMEM */ /* * Prevent people trying to call kunmap_atomic() as if it were kunmap() diff --git a/mm/highmem.c b/mm/highmem.c index 77677c6844f7..499dfafd36b7 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -31,12 +31,6 @@ #include #include -#ifndef CONFIG_KMAP_LOCAL -#ifdef CONFIG_HIGHMEM -DEFINE_PER_CPU(int, __kmap_atomic_idx); -#endif -#endif - /* * Virtual_count is not a pure "count". * 0 means that it is not mapped, and has not been mapped @@ -410,6 +404,7 @@ static inline void kmap_local_idx_pop(void) #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 -- cgit v1.2.3 From 351191ad55c8a1eccaf23e4187c62056229c0779 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 3 Nov 2020 10:27:32 +0100 Subject: io-mapping: Cleanup atomic iomap Switch the atomic iomap implementation over to kmap_local and stick the preempt/pagefault mechanics into the generic code similar to the kmap_atomic variants. Rename the x86 map function in preparation for a non-atomic variant. Signed-off-by: Thomas Gleixner Cc: Linus Torvalds Cc: Christoph Hellwig Cc: Andrew Morton Link: https://lore.kernel.org/r/20201103095858.625310005@linutronix.de --- arch/x86/include/asm/iomap.h | 9 +-------- arch/x86/mm/iomap_32.c | 6 ++---- include/linux/io-mapping.h | 8 ++++++-- 3 files changed, 9 insertions(+), 14 deletions(-) (limited to 'include/linux') diff --git a/arch/x86/include/asm/iomap.h b/arch/x86/include/asm/iomap.h index 0be7a30fd6bc..e2de092fc38c 100644 --- a/arch/x86/include/asm/iomap.h +++ b/arch/x86/include/asm/iomap.h @@ -13,14 +13,7 @@ #include #include -void __iomem *iomap_atomic_pfn_prot(unsigned long pfn, pgprot_t prot); - -static inline void iounmap_atomic(void __iomem *vaddr) -{ - kunmap_local_indexed((void __force *)vaddr); - pagefault_enable(); - preempt_enable(); -} +void __iomem *__iomap_local_pfn_prot(unsigned long pfn, pgprot_t prot); int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot); diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c index e0a40d7cc66c..9aaa756ddf21 100644 --- a/arch/x86/mm/iomap_32.c +++ b/arch/x86/mm/iomap_32.c @@ -44,7 +44,7 @@ void iomap_free(resource_size_t base, unsigned long size) } EXPORT_SYMBOL_GPL(iomap_free); -void __iomem *iomap_atomic_pfn_prot(unsigned long pfn, pgprot_t prot) +void __iomem *__iomap_local_pfn_prot(unsigned long pfn, pgprot_t prot) { /* * For non-PAT systems, translate non-WB request to UC- just in @@ -60,8 +60,6 @@ void __iomem *iomap_atomic_pfn_prot(unsigned long pfn, pgprot_t prot) /* Filter out unsupported __PAGE_KERNEL* bits: */ pgprot_val(prot) &= __default_kernel_pte_mask; - preempt_disable(); - pagefault_disable(); return (void __force __iomem *)__kmap_local_pfn_prot(pfn, prot); } -EXPORT_SYMBOL_GPL(iomap_atomic_pfn_prot); +EXPORT_SYMBOL_GPL(__iomap_local_pfn_prot); diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h index 3b0940be72e9..60e7c83e4904 100644 --- a/include/linux/io-mapping.h +++ b/include/linux/io-mapping.h @@ -69,13 +69,17 @@ io_mapping_map_atomic_wc(struct io_mapping *mapping, BUG_ON(offset >= mapping->size); phys_addr = mapping->base + offset; - return iomap_atomic_pfn_prot(PHYS_PFN(phys_addr), mapping->prot); + preempt_disable(); + pagefault_disable(); + return __iomap_local_pfn_prot(PHYS_PFN(phys_addr), mapping->prot); } static inline void io_mapping_unmap_atomic(void __iomem *vaddr) { - iounmap_atomic(vaddr); + kunmap_local_indexed((void __force *)vaddr); + pagefault_enable(); + preempt_enable(); } static inline void __iomem * -- cgit v1.2.3 From 13f876ba77ebd5125799bb042201f22cf73df154 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 3 Nov 2020 10:27:34 +0100 Subject: highmem: High implementation details and document API Move the gory details of kmap & al into a private header and only document the interfaces which are usable by drivers. Signed-off-by: Thomas Gleixner Cc: Linus Torvalds Cc: Christoph Hellwig Cc: Andrew Morton Link: https://lore.kernel.org/r/20201103095858.827582066@linutronix.de --- include/linux/highmem-internal.h | 174 +++++++++++++++++++++++++ include/linux/highmem.h | 266 ++++++++++++++------------------------- mm/highmem.c | 11 +- 3 files changed, 274 insertions(+), 177 deletions(-) create mode 100644 include/linux/highmem-internal.h (limited to 'include/linux') diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h new file mode 100644 index 000000000000..6ceed907b14e --- /dev/null +++ b/include/linux/highmem-internal.h @@ -0,0 +1,174 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_HIGHMEM_INTERNAL_H +#define _LINUX_HIGHMEM_INTERNAL_H + +/* + * 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 +#include + +#ifndef ARCH_HAS_KMAP_FLUSH_TLB +static inline void kmap_flush_tlb(unsigned long addr) { } +#endif + +#ifndef kmap_prot +#define kmap_prot PAGE_KERNEL +#endif + +void *kmap_high(struct page *page); +void kunmap_high(struct page *page); +void __kmap_flush_unused(void); +struct page *__kmap_to_page(void *addr); + +static inline void *kmap(struct page *page) +{ + void *addr; + + might_sleep(); + if (!PageHighMem(page)) + addr = page_address(page); + else + addr = kmap_high(page); + kmap_flush_tlb((unsigned long)addr); + return addr; +} + +static inline void kunmap(struct page *page) +{ + might_sleep(); + if (!PageHighMem(page)) + return; + kunmap_high(page); +} + +static inline struct page *kmap_to_page(void *addr) +{ + return __kmap_to_page(addr); +} + +static inline void kmap_flush_unused(void) +{ + __kmap_flush_unused(); +} + +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(struct page *page) +{ + return kmap_atomic_prot(page, kmap_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); + pagefault_enable(); + preempt_enable(); +} + +unsigned int __nr_free_highpages(void); +extern atomic_long_t _totalhigh_pages; + +static inline unsigned int nr_free_highpages(void) +{ + return __nr_free_highpages(); +} + +static inline unsigned long totalhigh_pages(void) +{ + return (unsigned long)atomic_long_read(&_totalhigh_pages); +} + +static inline void totalhigh_pages_inc(void) +{ + atomic_long_inc(&_totalhigh_pages); +} + +static inline void totalhigh_pages_add(long count) +{ + atomic_long_add(count, &_totalhigh_pages); +} + +#else /* CONFIG_HIGHMEM */ + +static inline struct page *kmap_to_page(void *addr) +{ + return virt_to_page(addr); +} + +static inline void *kmap(struct page *page) +{ + might_sleep(); + return page_address(page); +} + +static inline void kunmap_high(struct page *page) { } +static inline void kmap_flush_unused(void) { } + +static inline void kunmap(struct page *page) +{ +#ifdef ARCH_HAS_FLUSH_ON_KUNMAP + kunmap_flush_on_unmap(page_address(page)); +#endif +} + +static inline void *kmap_atomic(struct page *page) +{ + preempt_disable(); + pagefault_disable(); + return page_address(page); +} + +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) +{ +#ifdef ARCH_HAS_FLUSH_ON_KUNMAP + kunmap_flush_on_unmap(addr); +#endif + pagefault_enable(); + preempt_enable(); +} + +static inline unsigned int nr_free_highpages(void) { return 0; } +static inline unsigned long totalhigh_pages(void) { return 0UL; } + +#endif /* CONFIG_HIGHMEM */ + +/* + * 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(__addr); \ +} while (0) + +#endif diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 3180a8f7307f..7d098bd621f6 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -11,199 +11,125 @@ #include -#ifndef ARCH_HAS_FLUSH_ANON_PAGE -static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr) -{ -} -#endif - -#ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE -static inline void flush_kernel_dcache_page(struct page *page) -{ -} -static inline void flush_kernel_vmap_range(void *vaddr, int size) -{ -} -static inline void invalidate_kernel_vmap_range(void *vaddr, int size) -{ -} -#endif +#include "highmem-internal.h" -/* - * Outside of CONFIG_HIGHMEM to support X86 32bit iomap_atomic() cruft. +/** + * kmap - Map a page for long term usage + * @page: Pointer to the page to be mapped + * + * Returns: The virtual address of the mapping + * + * Can only be invoked from preemptible task context because on 32bit + * systems with CONFIG_HIGHMEM enabled this function might sleep. + * + * For systems with CONFIG_HIGHMEM=n and for pages in the low memory area + * this returns the virtual address of the direct kernel mapping. + * + * The returned virtual address is globally visible and valid up to the + * point where it is unmapped via kunmap(). The pointer can be handed to + * other contexts. + * + * For highmem pages on 32bit systems this can be slow as the mapping space + * is limited and protected by a global lock. In case that there is no + * mapping slot available the function blocks until a slot is released via + * kunmap(). */ -#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 -#include +static inline void *kmap(struct page *page); -#ifndef ARCH_HAS_KMAP_FLUSH_TLB -static inline void kmap_flush_tlb(unsigned long addr) { } -#endif - -#ifndef kmap_prot -#define kmap_prot PAGE_KERNEL -#endif - -void *kmap_high(struct page *page); -static inline void *kmap(struct page *page) -{ - void *addr; - - might_sleep(); - if (!PageHighMem(page)) - addr = page_address(page); - else - addr = kmap_high(page); - kmap_flush_tlb((unsigned long)addr); - return addr; -} +/** + * kunmap - Unmap the virtual address mapped by kmap() + * @addr: Virtual address to be unmapped + * + * Counterpart to kmap(). A NOOP for CONFIG_HIGHMEM=n and for mappings of + * pages in the low memory area. + */ +static inline void kunmap(struct page *page); -void kunmap_high(struct page *page); +/** + * kmap_to_page - Get the page for a kmap'ed address + * @addr: The address to look up + * + * Returns: The page which is mapped to @addr. + */ +static inline struct page *kmap_to_page(void *addr); -static inline void kunmap(struct page *page) -{ - might_sleep(); - if (!PageHighMem(page)) - return; - kunmap_high(page); -} +/** + * kmap_flush_unused - Flush all unused kmap mappings in order to + * remove stray mappings + */ +static inline void kmap_flush_unused(void); -/* - * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because - * no global lock is needed and because the kmap code must perform a global TLB - * invalidation when the kmap pool wraps. +/** + * kmap_atomic - Atomically map a page for temporary usage + * @page: Pointer to the page to be mapped + * + * Returns: The virtual address of the mapping + * + * Side effect: On return pagefaults and preemption are disabled. + * + * Can be invoked from any context. * - * However when holding an atomic kmap it is not legal to sleep, so atomic - * kmaps are appropriate for short, tight code paths only. + * Requires careful handling when nesting multiple mappings because the map + * management is stack based. The unmap has to be in the reverse order of + * the map operation: * - * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap - * gives a more generic (and caching) interface. But kmap_atomic can - * be used in IRQ contexts, so in some (very limited) cases we need - * it. + * addr1 = kmap_atomic(page1); + * addr2 = kmap_atomic(page2); + * ... + * kunmap_atomic(addr2); + * kunmap_atomic(addr1); + * + * Unmapping addr1 before addr2 is invalid and causes malfunction. + * + * Contrary to kmap() mappings the mapping is only valid in the context of + * the caller and cannot be handed to other contexts. + * + * On CONFIG_HIGHMEM=n kernels and for low memory pages this returns the + * virtual address of the direct mapping. Only real highmem pages are + * temporarily mapped. + * + * While it is significantly faster than kmap() it comes with restrictions + * about the pointer validity and the side effects of disabling page faults + * and preemption. Use it only when absolutely necessary, e.g. from non + * preemptible contexts. */ -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(struct page *page); -static inline void *kmap_atomic(struct page *page) -{ - return kmap_atomic_prot(page, kmap_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); -} - -/* declarations for linux/mm/highmem.c */ -unsigned int nr_free_highpages(void); -extern atomic_long_t _totalhigh_pages; -static inline unsigned long totalhigh_pages(void) -{ - return (unsigned long)atomic_long_read(&_totalhigh_pages); -} - -static inline void totalhigh_pages_inc(void) -{ - atomic_long_inc(&_totalhigh_pages); -} - -static inline void totalhigh_pages_add(long count) -{ - atomic_long_add(count, &_totalhigh_pages); -} - -void kmap_flush_unused(void); - -struct page *kmap_to_page(void *addr); - -#else /* CONFIG_HIGHMEM */ - -static inline unsigned int nr_free_highpages(void) { return 0; } - -static inline struct page *kmap_to_page(void *addr) -{ - return virt_to_page(addr); -} - -static inline unsigned long totalhigh_pages(void) { return 0UL; } +/** + * kunmap_atomic - Unmap the virtual address mapped by kmap_atomic() + * @addr: Virtual address to be unmapped + * + * Counterpart to kmap_atomic(). + * + * Undoes the side effects of kmap_atomic(), i.e. reenabling pagefaults and + * preemption. + * + * Other than that a NOOP for CONFIG_HIGHMEM=n and for mappings of pages + * in the low memory area. For real highmen pages the mapping which was + * established with kmap_atomic() is destroyed. + */ -static inline void *kmap(struct page *page) -{ - might_sleep(); - return page_address(page); -} +/* Highmem related interfaces for management code */ +static inline unsigned int nr_free_highpages(void); +static inline unsigned long totalhigh_pages(void); -static inline void kunmap_high(struct page *page) +#ifndef ARCH_HAS_FLUSH_ANON_PAGE +static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr) { } - -static inline void kunmap(struct page *page) -{ -#ifdef ARCH_HAS_FLUSH_ON_KUNMAP - kunmap_flush_on_unmap(page_address(page)); #endif -} -static inline void *kmap_atomic(struct page *page) +#ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE +static inline void flush_kernel_dcache_page(struct page *page) { - preempt_disable(); - pagefault_disable(); - return page_address(page); } - -static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot) +static inline void flush_kernel_vmap_range(void *vaddr, int size) { - return kmap_atomic(page); } - -static inline void *kmap_atomic_pfn(unsigned long pfn) +static inline void invalidate_kernel_vmap_range(void *vaddr, int size) { - 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 and preemption - */ -#ifdef ARCH_HAS_FLUSH_ON_KUNMAP - kunmap_flush_on_unmap(addr); #endif -} - -#define kmap_flush_unused() do {} while(0) - - -#endif /* CONFIG_HIGHMEM */ - -/* - * 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(__addr); \ - pagefault_enable(); \ - preempt_enable(); \ -} while (0) /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */ #ifndef clear_user_highpage diff --git a/mm/highmem.c b/mm/highmem.c index 499dfafd36b7..54bd233846c9 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -104,7 +104,7 @@ static inline wait_queue_head_t *get_pkmap_wait_queue_head(unsigned int color) atomic_long_t _totalhigh_pages __read_mostly; EXPORT_SYMBOL(_totalhigh_pages); -unsigned int nr_free_highpages (void) +unsigned int __nr_free_highpages (void) { struct zone *zone; unsigned int pages = 0; @@ -141,7 +141,7 @@ pte_t * pkmap_page_table; do { spin_unlock(&kmap_lock); (void)(flags); } while (0) #endif -struct page *kmap_to_page(void *vaddr) +struct page *__kmap_to_page(void *vaddr) { unsigned long addr = (unsigned long)vaddr; @@ -152,7 +152,7 @@ struct page *kmap_to_page(void *vaddr) return virt_to_page(addr); } -EXPORT_SYMBOL(kmap_to_page); +EXPORT_SYMBOL(__kmap_to_page); static void flush_all_zero_pkmaps(void) { @@ -194,10 +194,7 @@ static void flush_all_zero_pkmaps(void) flush_tlb_kernel_range(PKMAP_ADDR(0), PKMAP_ADDR(LAST_PKMAP)); } -/** - * kmap_flush_unused - flush all unused kmap mappings in order to remove stray mappings - */ -void kmap_flush_unused(void) +void __kmap_flush_unused(void) { lock_kmap(); flush_all_zero_pkmaps(); -- cgit v1.2.3 From 5fbda3ecd14a5343644979c98d6eb65b7e7de9d8 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 18 Nov 2020 20:48:43 +0100 Subject: sched: highmem: Store local kmaps in task struct Instead of storing the map per CPU provide and use per task storage. That prepares for local kmaps which are preemptible. The context switch code is preparatory and not yet in use because kmap_atomic() runs with preemption disabled. Will be made usable in the next step. The context switch logic is safe even when an interrupt happens after clearing or before restoring the kmaps. The kmap index in task struct is not modified so any nesting kmap in an interrupt will use unused indices and on return the counter is the same as before. Also add an assert into the return to user space code. Going back to user space with an active kmap local is a nono. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20201118204007.372935758@linutronix.de --- include/linux/highmem-internal.h | 10 ++++ include/linux/sched.h | 9 ++++ kernel/entry/common.c | 2 + kernel/fork.c | 1 + kernel/sched/core.c | 25 ++++++++++ mm/highmem.c | 99 ++++++++++++++++++++++++++++++++++++---- 6 files changed, 136 insertions(+), 10 deletions(-) (limited to 'include/linux') diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h index 6ceed907b14e..c5a22177db85 100644 --- a/include/linux/highmem-internal.h +++ b/include/linux/highmem-internal.h @@ -9,6 +9,16 @@ 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); +void kmap_local_fork(struct task_struct *tsk); +void __kmap_local_sched_out(void); +void __kmap_local_sched_in(void); +static inline void kmap_assert_nomap(void) +{ + DEBUG_LOCKS_WARN_ON(current->kmap_ctrl.idx); +} +#else +static inline void kmap_local_fork(struct task_struct *tsk) { } +static inline void kmap_assert_nomap(void) { } #endif #ifdef CONFIG_HIGHMEM diff --git a/include/linux/sched.h b/include/linux/sched.h index a33f35f68060..8946911cee9f 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -34,6 +34,7 @@ #include #include #include +#include /* task_struct member predeclarations (sorted alphabetically): */ struct audit_context; @@ -629,6 +630,13 @@ struct wake_q_node { struct wake_q_node *next; }; +struct kmap_ctrl { +#ifdef CONFIG_KMAP_LOCAL + int idx; + pte_t pteval[KM_MAX_IDX]; +#endif +}; + struct task_struct { #ifdef CONFIG_THREAD_INFO_IN_TASK /* @@ -1294,6 +1302,7 @@ struct task_struct { unsigned int sequential_io; unsigned int sequential_io_avg; #endif + struct kmap_ctrl kmap_ctrl; #ifdef CONFIG_DEBUG_ATOMIC_SLEEP unsigned long task_state_change; #endif diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 2b8366693d5c..4ae1fe0898e9 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -2,6 +2,7 @@ #include #include +#include #include #include @@ -194,6 +195,7 @@ static void exit_to_user_mode_prepare(struct pt_regs *regs) /* Ensure that the address limit is intact and no locks are held */ addr_limit_user_check(); + kmap_assert_nomap(); lockdep_assert_irqs_disabled(); lockdep_sys_exit(); } diff --git a/kernel/fork.c b/kernel/fork.c index 32083db7a2a2..17dcd1817799 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -930,6 +930,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) account_kernel_stack(tsk, 1); kcov_task_init(tsk); + kmap_local_fork(tsk); #ifdef CONFIG_FAULT_INJECTION tsk->fail_nth = 0; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index c962922784d1..953abdbe1472 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4094,6 +4094,22 @@ static inline void finish_lock_switch(struct rq *rq) # define finish_arch_post_lock_switch() do { } while (0) #endif +static inline void kmap_local_sched_out(void) +{ +#ifdef CONFIG_KMAP_LOCAL + if (unlikely(current->kmap_ctrl.idx)) + __kmap_local_sched_out(); +#endif +} + +static inline void kmap_local_sched_in(void) +{ +#ifdef CONFIG_KMAP_LOCAL + if (unlikely(current->kmap_ctrl.idx)) + __kmap_local_sched_in(); +#endif +} + /** * prepare_task_switch - prepare to switch tasks * @rq: the runqueue preparing to switch @@ -4116,6 +4132,7 @@ prepare_task_switch(struct rq *rq, struct task_struct *prev, perf_event_task_sched_out(prev, next); rseq_preempt(prev); fire_sched_out_preempt_notifiers(prev, next); + kmap_local_sched_out(); prepare_task(next); prepare_arch_switch(next); } @@ -4182,6 +4199,14 @@ static struct rq *finish_task_switch(struct task_struct *prev) finish_lock_switch(rq); finish_arch_post_lock_switch(); kcov_finish_switch(current); + /* + * kmap_local_sched_out() is invoked with rq::lock held and + * interrupts disabled. There is no requirement for that, but the + * sched out code does not have an interrupt enabled section. + * Restoring the maps on sched in does not require interrupts being + * disabled either. + */ + kmap_local_sched_in(); fire_sched_in_preempt_notifiers(current); /* diff --git a/mm/highmem.c b/mm/highmem.c index 39aaca1a1ece..d1ef06aa6de6 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -365,8 +365,6 @@ EXPORT_SYMBOL(kunmap_high); #include -static DEFINE_PER_CPU(int, __kmap_local_idx); - /* * With DEBUG_KMAP_LOCAL the stack depth is doubled and every second * slot is unused which acts as a guard page @@ -379,23 +377,21 @@ static DEFINE_PER_CPU(int, __kmap_local_idx); static inline int kmap_local_idx_push(void) { - int idx = __this_cpu_add_return(__kmap_local_idx, KM_INCR) - 1; - WARN_ON_ONCE(in_irq() && !irqs_disabled()); - BUG_ON(idx >= KM_MAX_IDX); - return idx; + current->kmap_ctrl.idx += KM_INCR; + BUG_ON(current->kmap_ctrl.idx >= KM_MAX_IDX); + return current->kmap_ctrl.idx - 1; } static inline int kmap_local_idx(void) { - return __this_cpu_read(__kmap_local_idx) - 1; + return current->kmap_ctrl.idx - 1; } static inline void kmap_local_idx_pop(void) { - int idx = __this_cpu_sub_return(__kmap_local_idx, KM_INCR); - - BUG_ON(idx < 0); + current->kmap_ctrl.idx -= KM_INCR; + BUG_ON(current->kmap_ctrl.idx < 0); } #ifndef arch_kmap_local_post_map @@ -464,6 +460,7 @@ void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot) pteval = pfn_pte(pfn, prot); set_pte_at(&init_mm, vaddr, kmap_pte - idx, pteval); arch_kmap_local_post_map(vaddr, pteval); + current->kmap_ctrl.pteval[kmap_local_idx()] = pteval; preempt_enable(); return (void *)vaddr; @@ -522,10 +519,92 @@ void kunmap_local_indexed(void *vaddr) arch_kmap_local_pre_unmap(addr); pte_clear(&init_mm, addr, kmap_pte - idx); arch_kmap_local_post_unmap(addr); + current->kmap_ctrl.pteval[kmap_local_idx()] = __pte(0); kmap_local_idx_pop(); preempt_enable(); } EXPORT_SYMBOL(kunmap_local_indexed); + +/* + * Invoked before switch_to(). This is safe even when during or after + * clearing the maps an interrupt which needs a kmap_local happens because + * the task::kmap_ctrl.idx is not modified by the unmapping code so a + * nested kmap_local will use the next unused index and restore the index + * on unmap. The already cleared kmaps of the outgoing task are irrelevant + * because the interrupt context does not know about them. The same applies + * when scheduling back in for an interrupt which happens before the + * restore is complete. + */ +void __kmap_local_sched_out(void) +{ + struct task_struct *tsk = current; + pte_t *kmap_pte = kmap_get_pte(); + int i; + + /* Clear kmaps */ + for (i = 0; i < tsk->kmap_ctrl.idx; i++) { + pte_t pteval = tsk->kmap_ctrl.pteval[i]; + unsigned long addr; + int idx; + + /* With debug all even slots are unmapped and act as guard */ + if (IS_ENABLED(CONFIG_DEBUG_HIGHMEM) && !(i & 0x01)) { + WARN_ON_ONCE(!pte_none(pteval)); + continue; + } + if (WARN_ON_ONCE(pte_none(pteval))) + continue; + + /* + * This is a horrible hack for XTENSA to calculate the + * coloured PTE index. Uses the PFN encoded into the pteval + * and the map index calculation because the actual mapped + * virtual address is not stored in task::kmap_ctrl. + * For any sane architecture this is optimized out. + */ + idx = arch_kmap_local_map_idx(i, pte_pfn(pteval)); + + 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); + } +} + +void __kmap_local_sched_in(void) +{ + struct task_struct *tsk = current; + pte_t *kmap_pte = kmap_get_pte(); + int i; + + /* Restore kmaps */ + for (i = 0; i < tsk->kmap_ctrl.idx; i++) { + pte_t pteval = tsk->kmap_ctrl.pteval[i]; + unsigned long addr; + int idx; + + /* With debug all even slots are unmapped and act as guard */ + if (IS_ENABLED(CONFIG_DEBUG_HIGHMEM) && !(i & 0x01)) { + WARN_ON_ONCE(!pte_none(pteval)); + continue; + } + if (WARN_ON_ONCE(pte_none(pteval))) + continue; + + /* See comment in __kmap_local_sched_out() */ + idx = arch_kmap_local_map_idx(i, pte_pfn(pteval)); + addr = __fix_to_virt(FIX_KMAP_BEGIN + idx); + set_pte_at(&init_mm, addr, kmap_pte - idx, pteval); + arch_kmap_local_post_map(addr, pteval); + } +} + +void kmap_local_fork(struct task_struct *tsk) +{ + if (WARN_ON_ONCE(tsk->kmap_ctrl.idx)) + memset(&tsk->kmap_ctrl, 0, sizeof(tsk->kmap_ctrl)); +} + #endif #if defined(HASHED_PAGE_VIRTUAL) -- cgit v1.2.3 From f3ba3c710ac5a30cd058615a9eb62d2ad95bb782 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 18 Nov 2020 20:48:44 +0100 Subject: mm/highmem: Provide kmap_local* Now that the kmap atomic index is stored in task struct provide a preemptible variant. On context switch the maps of an outgoing task are removed and the map of the incoming task are restored. That's obviously slow, but highmem is slow anyway. The kmap_local.*() functions can be invoked from both preemptible and atomic context. kmap local sections disable migration to keep the resulting virtual mapping address correct, but disable neither pagefaults nor preemption. A wholesale conversion of kmap_atomic to be fully preemptible is not possible because some of the usage sites might rely on the preemption disable for serialization or on the implicit pagefault disable. Needs to be done on a case by case basis. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20201118204007.468533059@linutronix.de --- include/linux/highmem-internal.h | 48 ++++++++++++++++++++++++++++++++++++++++ include/linux/highmem.h | 43 +++++++++++++++++++++-------------- mm/highmem.c | 6 +++++ 3 files changed, 81 insertions(+), 16 deletions(-) (limited to 'include/linux') diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h index c5a22177db85..1bbe96dc8be6 100644 --- a/include/linux/highmem-internal.h +++ b/include/linux/highmem-internal.h @@ -68,6 +68,26 @@ static inline void kmap_flush_unused(void) __kmap_flush_unused(); } +static inline void *kmap_local_page(struct page *page) +{ + return __kmap_local_page_prot(page, kmap_prot); +} + +static inline void *kmap_local_page_prot(struct page *page, pgprot_t prot) +{ + return __kmap_local_page_prot(page, prot); +} + +static inline void *kmap_local_pfn(unsigned long pfn) +{ + return __kmap_local_pfn_prot(pfn, kmap_prot); +} + +static inline void __kunmap_local(void *vaddr) +{ + kunmap_local_indexed(vaddr); +} + static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot) { preempt_disable(); @@ -140,6 +160,28 @@ static inline void kunmap(struct page *page) #endif } +static inline void *kmap_local_page(struct page *page) +{ + return page_address(page); +} + +static inline void *kmap_local_page_prot(struct page *page, pgprot_t prot) +{ + return kmap_local_page(page); +} + +static inline void *kmap_local_pfn(unsigned long pfn) +{ + return kmap_local_page(pfn_to_page(pfn)); +} + +static inline void __kunmap_local(void *addr) +{ +#ifdef ARCH_HAS_FLUSH_ON_KUNMAP + kunmap_flush_on_unmap(addr); +#endif +} + static inline void *kmap_atomic(struct page *page) { preempt_disable(); @@ -181,4 +223,10 @@ do { \ __kunmap_atomic(__addr); \ } while (0) +#define kunmap_local(__addr) \ +do { \ + BUILD_BUG_ON(__same_type((__addr), struct page *)); \ + __kunmap_local(__addr); \ +} while (0) + #endif diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 7d098bd621f6..f597830f26b4 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -60,24 +60,22 @@ static inline struct page *kmap_to_page(void *addr); static inline void kmap_flush_unused(void); /** - * kmap_atomic - Atomically map a page for temporary usage + * kmap_local_page - Map a page for temporary usage * @page: Pointer to the page to be mapped * * Returns: The virtual address of the mapping * - * Side effect: On return pagefaults and preemption are disabled. - * * Can be invoked from any context. * * Requires careful handling when nesting multiple mappings because the map * management is stack based. The unmap has to be in the reverse order of * the map operation: * - * addr1 = kmap_atomic(page1); - * addr2 = kmap_atomic(page2); + * addr1 = kmap_local_page(page1); + * addr2 = kmap_local_page(page2); * ... - * kunmap_atomic(addr2); - * kunmap_atomic(addr1); + * kunmap_local(addr2); + * kunmap_local(addr1); * * Unmapping addr1 before addr2 is invalid and causes malfunction. * @@ -88,10 +86,26 @@ static inline void kmap_flush_unused(void); * virtual address of the direct mapping. Only real highmem pages are * temporarily mapped. * - * While it is significantly faster than kmap() it comes with restrictions - * about the pointer validity and the side effects of disabling page faults - * and preemption. Use it only when absolutely necessary, e.g. from non - * preemptible contexts. + * While it is significantly faster than kmap() for the higmem case it + * comes with restrictions about the pointer validity. Only use when really + * necessary. + * + * On HIGHMEM enabled systems mapping a highmem page has the side effect of + * disabling migration in order to keep the virtual address stable across + * preemption. No caller of kmap_local_page() can rely on this side effect. + */ +static inline void *kmap_local_page(struct page *page); + +/** + * kmap_atomic - Atomically map a page for temporary usage - Deprecated! + * @page: Pointer to the page to be mapped + * + * Returns: The virtual address of the mapping + * + * Effectively a wrapper around kmap_local_page() which disables pagefaults + * and preemption. + * + * Do not use in new code. Use kmap_local_page() instead. */ static inline void *kmap_atomic(struct page *page); @@ -101,12 +115,9 @@ static inline void *kmap_atomic(struct page *page); * * Counterpart to kmap_atomic(). * - * Undoes the side effects of kmap_atomic(), i.e. reenabling pagefaults and + * Effectively a wrapper around kunmap_local() which additionally undoes + * the side effects of kmap_atomic(), i.e. reenabling pagefaults and * preemption. - * - * Other than that a NOOP for CONFIG_HIGHMEM=n and for mappings of pages - * in the low memory area. For real highmen pages the mapping which was - * established with kmap_atomic() is destroyed. */ /* Highmem related interfaces for management code */ diff --git a/mm/highmem.c b/mm/highmem.c index d1ef06aa6de6..83f9660f168f 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -453,6 +453,11 @@ void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot) unsigned long vaddr; int idx; + /* + * Disable migration so resulting virtual address is stable + * accross preemption. + */ + migrate_disable(); preempt_disable(); idx = arch_kmap_local_map_idx(kmap_local_idx_push(), pfn); vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); @@ -522,6 +527,7 @@ void kunmap_local_indexed(void *vaddr) current->kmap_ctrl.pteval[kmap_local_idx()] = __pte(0); kmap_local_idx_pop(); preempt_enable(); + migrate_enable(); } EXPORT_SYMBOL(kunmap_local_indexed); -- cgit v1.2.3 From e66f6e095486f0210fcf3c5eb3ecf13fa348be4c Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 18 Nov 2020 20:48:45 +0100 Subject: io-mapping: Provide iomap_local variant Similar to kmap local provide a iomap local variant which only disables migration, but neither disables pagefaults nor preemption. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20201118204007.561220818@linutronix.de --- Documentation/driver-api/io-mapping.rst | 74 ++++++++++++++++++++------------- include/linux/io-mapping.h | 30 ++++++++++++- 2 files changed, 73 insertions(+), 31 deletions(-) (limited to 'include/linux') diff --git a/Documentation/driver-api/io-mapping.rst b/Documentation/driver-api/io-mapping.rst index e33b88268554..a0cfb15988df 100644 --- a/Documentation/driver-api/io-mapping.rst +++ b/Documentation/driver-api/io-mapping.rst @@ -20,55 +20,71 @@ A mapping object is created during driver initialization using:: mappable, while 'size' indicates how large a mapping region to enable. Both are in bytes. -This _wc variant provides a mapping which may only be used -with the io_mapping_map_atomic_wc or io_mapping_map_wc. +This _wc variant provides a mapping which may only be used with +io_mapping_map_atomic_wc(), io_mapping_map_local_wc() or +io_mapping_map_wc(). -With this mapping object, individual pages can be mapped either atomically -or not, depending on the necessary scheduling environment. Of course, atomic -maps are more efficient:: +With this mapping object, individual pages can be mapped either temporarily +or long term, depending on the requirements. Of course, temporary maps are +more efficient. They come in two flavours:: + + void *io_mapping_map_local_wc(struct io_mapping *mapping, + unsigned long offset) void *io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset) -'offset' is the offset within the defined mapping region. -Accessing addresses beyond the region specified in the -creation function yields undefined results. Using an offset -which is not page aligned yields an undefined result. The -return value points to a single page in CPU address space. +'offset' is the offset within the defined mapping region. Accessing +addresses beyond the region specified in the creation function yields +undefined results. Using an offset which is not page aligned yields an +undefined result. The return value points to a single page in CPU address +space. -This _wc variant returns a write-combining map to the -page and may only be used with mappings created by -io_mapping_create_wc +This _wc variant returns a write-combining map to the page and may only be +used with mappings created by io_mapping_create_wc() -Note that the task may not sleep while holding this page -mapped. +Temporary mappings are only valid in the context of the caller. The mapping +is not guaranteed to be globaly visible. -:: +io_mapping_map_local_wc() has a side effect on X86 32bit as it disables +migration to make the mapping code work. No caller can rely on this side +effect. - void io_mapping_unmap_atomic(void *vaddr) +io_mapping_map_atomic_wc() has the side effect of disabling preemption and +pagefaults. Don't use in new code. Use io_mapping_map_local_wc() instead. -'vaddr' must be the value returned by the last -io_mapping_map_atomic_wc call. This unmaps the specified -page and allows the task to sleep once again. +Nested mappings need to be undone in reverse order because the mapping +code uses a stack for keeping track of them:: -If you need to sleep while holding the lock, you can use the non-atomic -variant, although they may be significantly slower. + addr1 = io_mapping_map_local_wc(map1, offset1); + addr2 = io_mapping_map_local_wc(map2, offset2); + ... + io_mapping_unmap_local(addr2); + io_mapping_unmap_local(addr1); -:: +The mappings are released with:: + + void io_mapping_unmap_local(void *vaddr) + void io_mapping_unmap_atomic(void *vaddr) + +'vaddr' must be the value returned by the last io_mapping_map_local_wc() or +io_mapping_map_atomic_wc() call. This unmaps the specified mapping and +undoes the side effects of the mapping functions. + +If you need to sleep while holding a mapping, you can use the regular +variant, although this may be significantly slower:: void *io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset) -This works like io_mapping_map_atomic_wc except it allows -the task to sleep while holding the page mapped. - +This works like io_mapping_map_atomic/local_wc() except it has no side +effects and the pointer is globaly visible. -:: +The mappings are released with:: void io_mapping_unmap(void *vaddr) -This works like io_mapping_unmap_atomic, except it is used -for pages mapped with io_mapping_map_wc. +Use for pages mapped with io_mapping_map_wc(). At driver close time, the io_mapping object must be freed:: diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h index 60e7c83e4904..c093e81310a9 100644 --- a/include/linux/io-mapping.h +++ b/include/linux/io-mapping.h @@ -82,6 +82,21 @@ io_mapping_unmap_atomic(void __iomem *vaddr) preempt_enable(); } +static inline void __iomem * +io_mapping_map_local_wc(struct io_mapping *mapping, unsigned long offset) +{ + resource_size_t phys_addr; + + BUG_ON(offset >= mapping->size); + phys_addr = mapping->base + offset; + return __iomap_local_pfn_prot(PHYS_PFN(phys_addr), mapping->prot); +} + +static inline void io_mapping_unmap_local(void __iomem *vaddr) +{ + kunmap_local_indexed((void __force *)vaddr); +} + static inline void __iomem * io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset, @@ -101,7 +116,7 @@ io_mapping_unmap(void __iomem *vaddr) iounmap(vaddr); } -#else +#else /* HAVE_ATOMIC_IOMAP */ #include @@ -166,7 +181,18 @@ io_mapping_unmap_atomic(void __iomem *vaddr) preempt_enable(); } -#endif /* HAVE_ATOMIC_IOMAP */ +static inline void __iomem * +io_mapping_map_local_wc(struct io_mapping *mapping, unsigned long offset) +{ + return io_mapping_map_wc(mapping, offset, PAGE_SIZE); +} + +static inline void io_mapping_unmap_local(void __iomem *vaddr) +{ + io_mapping_unmap(vaddr); +} + +#endif /* !HAVE_ATOMIC_IOMAP */ static inline struct io_mapping * io_mapping_create_wc(resource_size_t base, -- cgit v1.2.3