/**
* 建立临时内核映射
* type和CPU共同确定用哪个固定映射的线性地址映射请求页。
*/
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 */
inc_preempt_count();
/**
* 如果被映射的页不属于高端内存，当然用不着映射。直接返回线性地址就行了。
*/
if (!PageHighMem(page))
return page_address(page);
/**
* 通过type和CPU确定线性地址。
*/
idx = type + KM_TYPE_NR*smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
#ifdef CONFIG_DEBUG_HIGHMEM
if (!pte_none(*(kmap_pte-idx)))
BUG();
#endif
/**
* 将线性地址与页表项建立映射。
*/
set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
/**
* 当然，最后必须刷新一下TLB。然后才能返回线性地址。
*/
__flush_tlb_one(vaddr);
return (void*) vaddr;
}
/*
* copy_user_page
* @to: kernel logical address
* @from: kernel logical address
* @address: U0 address to be mapped
* @page: page (virt_to_page(to))
*/
void copy_user_page(void *to, void *from, unsigned long address,
struct page *page)
{
extern void __copy_page_wb(void *to, void *from);
if (((address ^ (unsigned long)to) & CACHE_ALIAS) == 0)
__copy_page_wb(to, from);
else {
pgprot_t pgprot = __pgprot(_PAGE_PRESENT |
_PAGE_RW | _PAGE_CACHABLE |
_PAGE_DIRTY | _PAGE_ACCESSED |
_PAGE_HW_SHARED | _PAGE_FLAGS_HARD);
unsigned long phys_addr = virt_to_phys(to);
unsigned long p3_addr = P3SEG + (address & CACHE_ALIAS);
pgd_t *pgd = pgd_offset_k(p3_addr);
pud_t *pud = pud_offset(pgd, p3_addr);
pmd_t *pmd = pmd_offset(pud, p3_addr);
pte_t *pte = pte_offset_kernel(pmd, p3_addr);
pte_t entry;
unsigned long flags;
entry = pfn_pte(phys_addr >> PAGE_SHIFT, pgprot);
inc_preempt_count();
BUG_ON(atomic_inc_return(&concurreny_check[(address & CACHE_ALIAS)>>12]) != 1);
set_pte(pte, entry);
local_irq_save(flags);
flush_tlb_one(get_asid(), p3_addr);
local_irq_restore(flags);
update_mmu_cache(NULL, p3_addr, entry);
__copy_user_page((void *)p3_addr, from, to);
pte_clear(&init_mm, p3_addr, pte);
atomic_dec(&concurreny_check[(address & CACHE_ALIAS)>>12]);
dec_preempt_count();
}
}
void *kmap_atomic(struct page *page, enum km_type type)
{
unsigned long idx;
unsigned long vaddr;
/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
inc_preempt_count();
if (page < highmem_start_page)
return page_address(page);
idx = type + KM_TYPE_NR*smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
/* XXX Fix - Anton */
#if 0
__flush_cache_one(vaddr);
#else
flush_cache_all();
#endif
#ifdef CONFIG_DEBUG_HIGHMEM
BUG_ON(!pte_none(*(kmap_pte-idx)));
#endif
set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
/* XXX Fix - Anton */
#if 0
__flush_tlb_one(vaddr);
#else
flush_tlb_all();
#endif
return (void*) vaddr;
}
/*
* 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;
inc_preempt_count();
idx = type + KM_TYPE_NR*smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot));
flush_tlb_one(vaddr);
return (void*) vaddr;
}
/*
* 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.
*/
static void *__kmap_atomic_xen(struct page *page, enum km_type type, pgprot_t prot)
{
enum fixed_addresses idx;
unsigned long vaddr;
/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
inc_preempt_count();
if (page < highmem_start_page)
return page_address(page);
idx = type + KM_TYPE_NR*smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
#ifdef CONFIG_DEBUG_HIGHMEM
if (!pte_none(*(kmap_pte-idx)))
BUG();
#endif
set_pte_at_sync(&init_mm, vaddr, kmap_pte-idx, mk_pte(page,prot));
return (void*) vaddr;
}
/*
* 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 */
inc_preempt_count();
if (!PageHighMem(page))
return page_address(page);
idx = type + KM_TYPE_NR*smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
#ifdef CONFIG_DEBUG_HIGHMEM
if (!pte_none(*(kmap_pte-idx)))
BUG();
#endif
set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
__flush_tlb_one(vaddr);
return (void*) vaddr;
}
static inline void preempt_conditional_sti(struct pt_regs *regs)
{
inc_preempt_count();
if (regs->flags & X86_EFLAGS_IF)
local_irq_enable();
}
