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/*
* Copyright 2002 Andi Kleen, SuSE Labs.
* Thanks to Ben LaHaise for precious feedback.
*/
#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/mm.h>
void clflush_cache_range(void *addr, int size)
{
int i;
for (i = 0; i < size; i += boot_cpu_data.x86_clflush_size)
clflush(addr+i);
}
#include <asm/processor.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
pte_t *lookup_address(unsigned long address, int *level)
{
pgd_t *pgd = pgd_offset_k(address);
pud_t *pud;
pmd_t *pmd;
if (pgd_none(*pgd))
return NULL;
pud = pud_offset(pgd, address);
if (pud_none(*pud))
return NULL;
pmd = pmd_offset(pud, address);
if (pmd_none(*pmd))
return NULL;
*level = 3;
if (pmd_large(*pmd))
return (pte_t *)pmd;
*level = 4;
return pte_offset_kernel(pmd, address);
}
static struct page *
split_large_page(unsigned long address, pgprot_t ref_prot)
{
unsigned long addr;
struct page *base;
pte_t *pbase;
int i;
base = alloc_pages(GFP_KERNEL, 0);
if (!base)
return NULL;
address = __pa(address);
addr = address & LARGE_PAGE_MASK;
pbase = (pte_t *)page_address(base);
for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE)
pbase[i] = pfn_pte(addr >> PAGE_SHIFT, ref_prot);
return base;
}
static int
__change_page_attr(unsigned long address, struct page *page, pgprot_t prot)
{
struct page *kpte_page;
pte_t *kpte;
pgprot_t ref_prot2, oldprot;
int level;
repeat:
kpte = lookup_address(address, &level);
if (!kpte)
return 0;
kpte_page = virt_to_page(kpte);
oldprot = pte_pgprot(*kpte);
BUG_ON(PageLRU(kpte_page));
BUG_ON(PageCompound(kpte_page));
prot = canon_pgprot(prot);
if (level == 4) {
set_pte_atomic(kpte, mk_pte(page, prot));
} else {
/*
* split_large_page will take the reference for this
* change_page_attr on the split page.
*/
struct page *split;
ref_prot2 = pte_pgprot(pte_clrhuge(*kpte));
split = split_large_page(address, ref_prot2);
if (!split)
return -ENOMEM;
pgprot_val(ref_prot2) &= ~_PAGE_NX;
set_pte_atomic(kpte, mk_pte(split, ref_prot2));
goto repeat;
}
return 0;
}
/**
* change_page_attr_addr - Change page table attributes in linear mapping
* @address: Virtual address in linear mapping.
* @numpages: Number of pages to change
* @prot: New page table attribute (PAGE_*)
*
* Change page attributes of a page in the direct mapping. This is a variant
* of change_page_attr() that also works on memory holes that do not have
* mem_map entry (pfn_valid() is false).
*
* See change_page_attr() documentation for more details.
*/
int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
{
int err = 0, kernel_map = 0, i;
if (address >= __START_KERNEL_map &&
address < __START_KERNEL_map + KERNEL_TEXT_SIZE) {
address = (unsigned long)__va(__pa(address));
kernel_map = 1;
}
down_write(&init_mm.mmap_sem);
for (i = 0; i < numpages; i++, address += PAGE_SIZE) {
unsigned long pfn = __pa(address) >> PAGE_SHIFT;
if (!kernel_map || pte_present(pfn_pte(0, prot))) {
err = __change_page_attr(address, pfn_to_page(pfn), prot);
if (err)
break;
}
/* Handle kernel mapping too which aliases part of the
* lowmem */
if (__pa(address) < KERNEL_TEXT_SIZE) {
unsigned long addr2;
pgprot_t prot2;
addr2 = __START_KERNEL_map + __pa(address);
/* Make sure the kernel mappings stay executable */
prot2 = pte_pgprot(pte_mkexec(pfn_pte(0, prot)));
err = __change_page_attr(addr2, pfn_to_page(pfn), prot2);
}
}
up_write(&init_mm.mmap_sem);
return err;
}
/**
* change_page_attr - Change page table attributes in the linear mapping.
* @page: First page to change
* @numpages: Number of pages to change
* @prot: New protection/caching type (PAGE_*)
*
* Returns 0 on success, otherwise a negated errno.
*
* This should be used when a page is mapped with a different caching policy
* than write-back somewhere - some CPUs do not like it when mappings with
* different caching policies exist. This changes the page attributes of the
* in kernel linear mapping too.
*
* Caller must call global_flush_tlb() later to make the changes active.
*
* The caller needs to ensure that there are no conflicting mappings elsewhere
* (e.g. in user space) * This function only deals with the kernel linear map.
*
* For MMIO areas without mem_map use change_page_attr_addr() instead.
*/
int change_page_attr(struct page *page, int numpages, pgprot_t prot)
{
unsigned long addr = (unsigned long)page_address(page);
return change_page_attr_addr(addr, numpages, prot);
}
EXPORT_SYMBOL(change_page_attr);
static void flush_kernel_map(void *arg)
{
/*
* Flush all to work around Errata in early athlons regarding
* large page flushing.
*/
__flush_tlb_all();
if (boot_cpu_data.x86_model >= 4)
wbinvd();
}
void global_flush_tlb(void)
{
BUG_ON(irqs_disabled());
on_each_cpu(flush_kernel_map, NULL, 1, 1);
}
EXPORT_SYMBOL(global_flush_tlb);
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