diff options
Diffstat (limited to 'mm/highmem.c')
| -rw-r--r-- | mm/highmem.c | 392 |
1 files changed, 361 insertions, 31 deletions
diff --git a/mm/highmem.c b/mm/highmem.c index 1352a27951e3..bd48ba445dd4 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -23,7 +23,6 @@ #include <linux/bio.h> #include <linux/pagemap.h> #include <linux/mempool.h> -#include <linux/blkdev.h> #include <linux/init.h> #include <linux/hash.h> #include <linux/highmem.h> @@ -31,9 +30,16 @@ #include <asm/tlbflush.h> #include <linux/vmalloc.h> -#if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32) -DEFINE_PER_CPU(int, __kmap_atomic_idx); +#ifdef CONFIG_KMAP_LOCAL +static inline int kmap_local_calc_idx(int idx) +{ + return idx + KM_MAX_IDX * smp_processor_id(); +} + +#ifndef arch_kmap_local_map_idx +#define arch_kmap_local_map_idx(idx, pfn) kmap_local_calc_idx(idx) #endif +#endif /* CONFIG_KMAP_LOCAL */ /* * Virtual_count is not a pure "count". @@ -108,9 +114,7 @@ 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); -EXPORT_PER_CPU_SYMBOL(__kmap_atomic_idx); - -unsigned int nr_free_highpages (void) +unsigned int __nr_free_highpages(void) { struct zone *zone; unsigned int pages = 0; @@ -126,7 +130,7 @@ unsigned int nr_free_highpages (void) static int pkmap_count[LAST_PKMAP]; static __cacheline_aligned_in_smp DEFINE_SPINLOCK(kmap_lock); -pte_t * pkmap_page_table; +pte_t *pkmap_page_table; /* * Most architectures have no use for kmap_high_get(), so let's abstract @@ -147,18 +151,36 @@ 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 base = (unsigned long) vaddr & PAGE_MASK; + struct kmap_ctrl *kctrl = ¤t->kmap_ctrl; unsigned long addr = (unsigned long)vaddr; + int i; - if (addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP)) { - int i = PKMAP_NR(addr); - return pte_page(pkmap_page_table[i]); + /* kmap() mappings */ + if (WARN_ON_ONCE(addr >= PKMAP_ADDR(0) && + addr < PKMAP_ADDR(LAST_PKMAP))) + return pte_page(ptep_get(&pkmap_page_table[PKMAP_NR(addr)])); + + /* kmap_local_page() mappings */ + if (WARN_ON_ONCE(base >= __fix_to_virt(FIX_KMAP_END) && + base < __fix_to_virt(FIX_KMAP_BEGIN))) { + for (i = 0; i < kctrl->idx; i++) { + unsigned long base_addr; + int idx; + + idx = arch_kmap_local_map_idx(i, pte_pfn(pteval)); + base_addr = __fix_to_virt(FIX_KMAP_BEGIN + idx); + + if (base_addr == base) + return pte_page(kctrl->pteval[i]); + } } - return virt_to_page(addr); + return virt_to_page(vaddr); } -EXPORT_SYMBOL(kmap_to_page); +EXPORT_SYMBOL(__kmap_to_page); static void flush_all_zero_pkmaps(void) { @@ -169,6 +191,7 @@ static void flush_all_zero_pkmaps(void) for (i = 0; i < LAST_PKMAP; i++) { struct page *page; + pte_t ptent; /* * zero means we don't have anything to do, @@ -181,7 +204,8 @@ static void flush_all_zero_pkmaps(void) pkmap_count[i] = 0; /* sanity check */ - BUG_ON(pte_none(pkmap_page_table[i])); + ptent = ptep_get(&pkmap_page_table[i]); + BUG_ON(pte_none(ptent)); /* * Don't need an atomic fetch-and-clear op here; @@ -190,7 +214,7 @@ static void flush_all_zero_pkmaps(void) * getting the kmap_lock (which is held here). * So no dangers, even with speculative execution. */ - page = pte_page(pkmap_page_table[i]); + page = pte_page(ptent); pte_clear(&init_mm, PKMAP_ADDR(i), &pkmap_page_table[i]); set_page_address(page, NULL); @@ -200,10 +224,7 @@ 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(); @@ -287,9 +308,8 @@ void *kmap_high(struct page *page) pkmap_count[PKMAP_NR(vaddr)]++; BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 2); unlock_kmap(); - return (void*) vaddr; + return (void *) vaddr; } - EXPORT_SYMBOL(kmap_high); #ifdef ARCH_NEEDS_KMAP_HIGH_GET @@ -314,7 +334,7 @@ void *kmap_high_get(struct page *page) pkmap_count[PKMAP_NR(vaddr)]++; } unlock_kmap_any(flags); - return (void*) vaddr; + return (void *) vaddr; } #endif @@ -367,9 +387,323 @@ void kunmap_high(struct page *page) if (need_wakeup) wake_up(pkmap_map_wait); } - EXPORT_SYMBOL(kunmap_high); -#endif /* CONFIG_HIGHMEM */ + +void zero_user_segments(struct page *page, unsigned start1, unsigned end1, + unsigned start2, unsigned end2) +{ + unsigned int i; + + BUG_ON(end1 > page_size(page) || end2 > page_size(page)); + + if (start1 >= end1) + start1 = end1 = 0; + if (start2 >= end2) + start2 = end2 = 0; + + for (i = 0; i < compound_nr(page); i++) { + void *kaddr = NULL; + + if (start1 >= PAGE_SIZE) { + start1 -= PAGE_SIZE; + end1 -= PAGE_SIZE; + } else { + unsigned this_end = min_t(unsigned, end1, PAGE_SIZE); + + if (end1 > start1) { + kaddr = kmap_local_page(page + i); + memset(kaddr + start1, 0, this_end - start1); + } + end1 -= this_end; + start1 = 0; + } + + if (start2 >= PAGE_SIZE) { + start2 -= PAGE_SIZE; + end2 -= PAGE_SIZE; + } else { + unsigned this_end = min_t(unsigned, end2, PAGE_SIZE); + + if (end2 > start2) { + if (!kaddr) + kaddr = kmap_local_page(page + i); + memset(kaddr + start2, 0, this_end - start2); + } + end2 -= this_end; + start2 = 0; + } + + if (kaddr) { + kunmap_local(kaddr); + flush_dcache_page(page + i); + } + + if (!end1 && !end2) + break; + } + + BUG_ON((start1 | start2 | end1 | end2) != 0); +} +EXPORT_SYMBOL(zero_user_segments); +#endif /* CONFIG_HIGHMEM */ + +#ifdef CONFIG_KMAP_LOCAL + +#include <asm/kmap_size.h> + +/* + * With DEBUG_KMAP_LOCAL the stack depth is doubled and every second + * slot is unused which acts as a guard page + */ +#ifdef CONFIG_DEBUG_KMAP_LOCAL +# define KM_INCR 2 +#else +# define KM_INCR 1 +#endif + +static inline int kmap_local_idx_push(void) +{ + WARN_ON_ONCE(in_hardirq() && !irqs_disabled()); + 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 current->kmap_ctrl.idx - 1; +} + +static inline void kmap_local_idx_pop(void) +{ + current->kmap_ctrl.idx -= KM_INCR; + BUG_ON(current->kmap_ctrl.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_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 + +#ifndef arch_kmap_local_set_pte +#define arch_kmap_local_set_pte(mm, vaddr, ptep, ptev) \ + set_pte_at(mm, vaddr, ptep, ptev) +#endif + +/* Unmap a local mapping which was obtained by kmap_high_get() */ +static inline bool 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(ptep_get(&pkmap_page_table[PKMAP_NR(vaddr)]))); + return true; + } +#endif + return false; +} + +static pte_t *__kmap_pte; + +static pte_t *kmap_get_pte(unsigned long vaddr, int idx) +{ + if (IS_ENABLED(CONFIG_KMAP_LOCAL_NON_LINEAR_PTE_ARRAY)) + /* + * Set by the arch if __kmap_pte[-idx] does not produce + * the correct entry. + */ + return virt_to_kpte(vaddr); + if (!__kmap_pte) + __kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN)); + return &__kmap_pte[-idx]; +} + +void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot) +{ + pte_t pteval, *kmap_pte; + unsigned long vaddr; + int idx; + + /* + * Disable migration so resulting virtual address is stable + * across preemption. + */ + migrate_disable(); + preempt_disable(); + idx = arch_kmap_local_map_idx(kmap_local_idx_push(), pfn); + vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); + kmap_pte = kmap_get_pte(vaddr, idx); + BUG_ON(!pte_none(ptep_get(kmap_pte))); + pteval = pfn_pte(pfn, prot); + arch_kmap_local_set_pte(&init_mm, vaddr, kmap_pte, pteval); + arch_kmap_local_post_map(vaddr, pteval); + current->kmap_ctrl.pteval[kmap_local_idx()] = 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; + + /* + * To broaden the usage of the actual kmap_local() machinery always map + * pages when debugging is enabled and the architecture has no problems + * with alias mappings. + */ + if (!IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP) && !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(const void *vaddr) +{ + unsigned long addr = (unsigned long) vaddr & PAGE_MASK; + pte_t *kmap_pte; + int idx; + + if (addr < __fix_to_virt(FIX_KMAP_END) || + addr > __fix_to_virt(FIX_KMAP_BEGIN)) { + if (IS_ENABLED(CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP)) { + /* This _should_ never happen! See above. */ + WARN_ON_ONCE(1); + return; + } + /* + * Handle mappings which were obtained by kmap_high_get() + * first as the virtual address of such mappings is below + * PAGE_OFFSET. Warn for all other addresses which are in + * the user space part of the virtual address space. + */ + if (!kmap_high_unmap_local(addr)) + WARN_ON_ONCE(addr < PAGE_OFFSET); + return; + } + + preempt_disable(); + idx = arch_kmap_local_unmap_idx(kmap_local_idx(), addr); + WARN_ON_ONCE(addr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); + + kmap_pte = kmap_get_pte(addr, idx); + arch_kmap_local_pre_unmap(addr); + pte_clear(&init_mm, addr, kmap_pte); + arch_kmap_local_post_unmap(addr); + current->kmap_ctrl.pteval[kmap_local_idx()] = __pte(0); + kmap_local_idx_pop(); + preempt_enable(); + migrate_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; + 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_KMAP_LOCAL) && !(i & 0x01)) { + WARN_ON_ONCE(pte_val(pteval) != 0); + 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); + kmap_pte = kmap_get_pte(addr, idx); + arch_kmap_local_pre_unmap(addr); + pte_clear(&init_mm, addr, kmap_pte); + arch_kmap_local_post_unmap(addr); + } +} + +void __kmap_local_sched_in(void) +{ + struct task_struct *tsk = current; + pte_t *kmap_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_KMAP_LOCAL) && !(i & 0x01)) { + WARN_ON_ONCE(pte_val(pteval) != 0); + 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); + kmap_pte = kmap_get_pte(addr, idx); + set_pte_at(&init_mm, addr, kmap_pte, 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) @@ -423,15 +757,14 @@ void *page_address(const struct page *page) list_for_each_entry(pam, &pas->lh, list) { if (pam->page == page) { ret = pam->virtual; - goto done; + break; } } } -done: + spin_unlock_irqrestore(&pas->lock, flags); return ret; } - EXPORT_SYMBOL(page_address); /** @@ -461,14 +794,11 @@ void set_page_address(struct page *page, void *virtual) list_for_each_entry(pam, &pas->lh, list) { if (pam->page == page) { list_del(&pam->list); - spin_unlock_irqrestore(&pas->lock, flags); - goto done; + break; } } spin_unlock_irqrestore(&pas->lock, flags); } -done: - return; } void __init page_address_init(void) |