diff options
Diffstat (limited to 'mm/highmem.c')
| -rw-r--r-- | mm/highmem.c | 272 |
1 files changed, 257 insertions, 15 deletions
diff --git a/mm/highmem.c b/mm/highmem.c index 1352a27951e3..83f9660f168f 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -31,10 +31,6 @@ #include <asm/tlbflush.h> #include <linux/vmalloc.h> -#if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32) -DEFINE_PER_CPU(int, __kmap_atomic_idx); -#endif - /* * Virtual_count is not a pure "count". * 0 means that it is not mapped, and has not been mapped @@ -108,9 +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); -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; @@ -147,7 +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; @@ -158,7 +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) { @@ -200,10 +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(); @@ -367,9 +358,260 @@ 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 <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_irq() && !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_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 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(pkmap_page_table[PKMAP_NR(vaddr)])); + return true; + } +#endif + return false; +} + +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; + + /* + * 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); + 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); + 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(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)) { + 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)); + + 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(); + 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 = 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) |