135 lines
3.2 KiB
C
135 lines
3.2 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/highmem.h>
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#include <linux/export.h>
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#include <linux/swap.h> /* for totalram_pages */
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#include <linux/memblock.h>
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void *kmap(struct page *page)
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{
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might_sleep();
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if (!PageHighMem(page))
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return page_address(page);
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return kmap_high(page);
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}
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EXPORT_SYMBOL(kmap);
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void kunmap(struct page *page)
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{
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if (in_interrupt())
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BUG();
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if (!PageHighMem(page))
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return;
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kunmap_high(page);
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}
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EXPORT_SYMBOL(kunmap);
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/*
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* kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
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* no global lock is needed and because the kmap code must perform a global TLB
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* invalidation when the kmap pool wraps.
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*
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* However when holding an atomic kmap it is not legal to sleep, so atomic
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* kmaps are appropriate for short, tight code paths only.
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*/
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void *kmap_atomic_prot(struct page *page, pgprot_t prot)
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{
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unsigned long vaddr;
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int idx, type;
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preempt_disable();
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pagefault_disable();
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if (!PageHighMem(page))
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return page_address(page);
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type = kmap_atomic_idx_push();
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idx = type + KM_TYPE_NR*smp_processor_id();
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vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
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BUG_ON(!pte_none(*(kmap_pte-idx)));
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set_pte(kmap_pte-idx, mk_pte(page, prot));
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arch_flush_lazy_mmu_mode();
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return (void *)vaddr;
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}
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EXPORT_SYMBOL(kmap_atomic_prot);
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void *kmap_atomic(struct page *page)
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{
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return kmap_atomic_prot(page, kmap_prot);
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}
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EXPORT_SYMBOL(kmap_atomic);
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/*
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* This is the same as kmap_atomic() but can map memory that doesn't
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* have a struct page associated with it.
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*/
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void *kmap_atomic_pfn(unsigned long pfn)
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{
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return kmap_atomic_prot_pfn(pfn, kmap_prot);
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}
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EXPORT_SYMBOL_GPL(kmap_atomic_pfn);
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void __kunmap_atomic(void *kvaddr)
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{
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unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
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if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
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vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
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int idx, type;
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type = kmap_atomic_idx();
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idx = type + KM_TYPE_NR * smp_processor_id();
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#ifdef CONFIG_DEBUG_HIGHMEM
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WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
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#endif
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/*
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* Force other mappings to Oops if they'll try to access this
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* pte without first remap it. Keeping stale mappings around
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* is a bad idea also, in case the page changes cacheability
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* attributes or becomes a protected page in a hypervisor.
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*/
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kpte_clear_flush(kmap_pte-idx, vaddr);
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kmap_atomic_idx_pop();
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arch_flush_lazy_mmu_mode();
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}
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#ifdef CONFIG_DEBUG_HIGHMEM
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else {
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BUG_ON(vaddr < PAGE_OFFSET);
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BUG_ON(vaddr >= (unsigned long)high_memory);
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}
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#endif
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pagefault_enable();
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preempt_enable();
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}
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EXPORT_SYMBOL(__kunmap_atomic);
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void __init set_highmem_pages_init(void)
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{
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struct zone *zone;
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int nid;
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/*
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* Explicitly reset zone->managed_pages because set_highmem_pages_init()
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* is invoked before memblock_free_all()
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*/
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reset_all_zones_managed_pages();
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for_each_zone(zone) {
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unsigned long zone_start_pfn, zone_end_pfn;
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if (!is_highmem(zone))
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continue;
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zone_start_pfn = zone->zone_start_pfn;
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zone_end_pfn = zone_start_pfn + zone->spanned_pages;
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nid = zone_to_nid(zone);
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printk(KERN_INFO "Initializing %s for node %d (%08lx:%08lx)\n",
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zone->name, nid, zone_start_pfn, zone_end_pfn);
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add_highpages_with_active_regions(nid, zone_start_pfn,
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zone_end_pfn);
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}
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}
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