/*
* 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 void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
{
/* change init_mm */
set_pte_atomic(kpte, pte);
#ifdef CONFIG_X86_32
if (!SHARED_KERNEL_PMD) {
struct page *page;
for (page = pgd_list; page; page = (struct page *)page->index) {
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pgd = (pgd_t *)page_address(page) + pgd_index(address);
pud = pud_offset(pgd, address);
pmd = pmd_offset(pud, address);
set_pte_atomic((pte_t *)pmd, pte);
}
}
#endif
}
static int split_large_page(pte_t *kpte, unsigned long address)
{
pgprot_t ref_prot = pte_pgprot(pte_clrhuge(*kpte));
gfp_t gfp_flags = GFP_KERNEL;
unsigned long flags;
unsigned long addr;
pte_t *pbase, *tmp;
struct page *base;
int i, level;
#ifdef CONFIG_DEBUG_PAGEALLOC
gfp_flags = GFP_ATOMIC;
#endif
base = alloc_pages(gfp_flags, 0);
if (!base)
return -ENOMEM;
spin_lock_irqsave(&pgd_lock, flags);
/*
* Check for races, another CPU might have split this page
* up for us already:
*/
tmp = lookup_address(address, &level);
if (tmp != kpte) {
WARN_ON_ONCE(1);
goto out_unlock;
}
address = __pa(address);
addr = address & LARGE_PAGE_MASK;
pbase = (pte_t *)page_address(base);
#ifdef CONFIG_X86_32
paravirt_alloc_pt(&init_mm, page_to_pfn(base));
#endif
for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE)
set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT, ref_prot));
/*
* Install the new, split up pagetable:
*/
__set_pmd_pte(kpte, address, mk_pte(base, ref_prot));
base = NULL;
out_unlock:
spin_unlock_irqrestore(&pgd_lock, flags);
if (base)
__free_pages(base, 0);
return 0;
}
static int
__change_page_attr(unsigned long address, struct page *page, pgprot_t prot)
{
struct page *kpte_page;
int level, err = 0;
pte_t *kpte;
BUG_ON(PageHighMem(page));
repeat:
kpte = lookup_address(address, &level);
if (!kpte)
return -EINVAL;
kpte_page = virt_to_page(kpte);
BUG_ON(PageLRU(kpte_page));
BUG_ON(PageCompound(kpte_page));
/*
* Better fail early if someone sets the kernel text to NX.
* Does not cover __inittext
*/
BUG_ON(address >= (unsigned long)&_text &&
address < (unsigned long)&_etext &&
(pgprot_val(prot) & _PAGE_NX));
if (level == 4) {
set_pte_atomic(kpte, mk_pte(page, canon_pgprot(prot)));
} else {
err = split_large_page(kpte, address);
if (!err)
goto repeat;
}
return err;
}
/**
* 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;
#ifdef CONFIG_X86_64
if (address >= __START_KERNEL_map &&
address < __START_KERNEL_map + KERNEL_TEXT_SIZE) {
address = (unsigned long)__va(__pa(address));
kernel_map = 1;
}
#endif
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;
}
#ifdef CONFIG_X86_64
/*
* Handle kernel mapping too which aliases part of
* 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);
}
#endif
}
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);
#ifdef CONFIG_DEBUG_PAGEALLOC
void kernel_map_pages(struct page *page, int numpages, int enable)
{
if (PageHighMem(page))
return;
if (!enable) {
debug_check_no_locks_freed(page_address(page),
numpages * PAGE_SIZE);
}
/*
* If page allocator is not up yet then do not call c_p_a():
*/
if (!debug_pagealloc_enabled)
return;
/*
* The return value is ignored - the calls cannot fail,
* large pages are disabled at boot time:
*/
change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
/*
* We should perform an IPI and flush all tlbs,
* but that can deadlock->flush only current cpu:
*/
__flush_tlb_all();
}
#endif
