#include <linux/module.h> #include <linux/highmem.h> #include <linux/sched.h> #include <linux/smp.h> #include <asm/fixmap.h> #include <asm/tlbflush.h> static pte_t *kmap_pte; unsigned long highstart_pfn, highend_pfn; void *__kmap(struct page *page) { void *addr; might_sleep(); if (!PageHighMem(page)) return page_address(page); addr = kmap_high(page); flush_tlb_one((unsigned long)addr); return addr; } EXPORT_SYMBOL(__kmap); void __kunmap(struct page *page) { BUG_ON(in_interrupt()); if (!PageHighMem(page)) return; kunmap_high(page); } EXPORT_SYMBOL(__kunmap); /* * 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. * * However when holding an atomic kmap is is not legal to sleep, so atomic * kmaps are appropriate for short, tight code paths only. */ void *__kmap_atomic(struct page *page, enum km_type type) { enum fixed_addresses idx; unsigned long vaddr; /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ pagefault_disable(); if (!PageHighMem(page)) return page_address(page); debug_kmap_atomic(type); idx = type + KM_TYPE_NR*smp_processor_id(); vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); #ifdef CONFIG_DEBUG_HIGHMEM BUG_ON(!pte_none(*(kmap_pte - idx))); #endif set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL)); local_flush_tlb_one((unsigned long)vaddr); return (void*) vaddr; } EXPORT_SYMBOL(__kmap_atomic); void __kunmap_atomic(void *kvaddr, enum km_type type) { #ifdef CONFIG_DEBUG_HIGHMEM unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id(); if (vaddr < FIXADDR_START) { // FIXME pagefault_enable(); return; } BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); /* * force other mappings to Oops if they'll try to access * this pte without first remap it */ pte_clear(&init_mm, vaddr, kmap_pte-idx); local_flush_tlb_one(vaddr); #endif pagefault_enable(); } EXPORT_SYMBOL(__kunmap_atomic); /* * 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, enum km_type type) { enum fixed_addresses idx; unsigned long vaddr; pagefault_disable(); debug_kmap_atomic(type); idx = type + KM_TYPE_NR*smp_processor_id(); vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL)); flush_tlb_one(vaddr); return (void*) vaddr; } struct page *__kmap_atomic_to_page(void *ptr) { unsigned long idx, vaddr = (unsigned long)ptr; pte_t *pte; if (vaddr < FIXADDR_START) return virt_to_page(ptr); idx = virt_to_fix(vaddr); pte = kmap_pte - (idx - FIX_KMAP_BEGIN); return pte_page(*pte); } void __init kmap_init(void) { unsigned long kmap_vstart; /* cache the first kmap pte */ kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); kmap_pte = kmap_get_fixmap_pte(kmap_vstart); }