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authorVivek Goyal <vgoyal@in.ibm.com>2007-05-02 19:27:07 +0200
committerAndi Kleen <andi@basil.nowhere.org>2007-05-02 19:27:07 +0200
commit0dbf7028c0c1f266c9631139450a1502d3cd457e (patch)
tree2616edcd32d92b6539d2810fd3043b054baabb92 /arch/x86_64/mm
parent1b29c1643c0d82512477ccd97dc290198fe23e22 (diff)
[PATCH] x86: __pa and __pa_symbol address space separation
Currently __pa_symbol is for use with symbols in the kernel address map and __pa is for use with pointers into the physical memory map. But the code is implemented so you can usually interchange the two. __pa which is much more common can be implemented much more cheaply if it is it doesn't have to worry about any other kernel address spaces. This is especially true with a relocatable kernel as __pa_symbol needs to peform an extra variable read to resolve the address. There is a third macro that is added for the vsyscall data __pa_vsymbol for finding the physical addesses of vsyscall pages. Most of this patch is simply sorting through the references to __pa or __pa_symbol and using the proper one. A little of it is continuing to use a physical address when we have it instead of recalculating it several times. swapper_pgd is now NULL. leave_mm now uses init_mm.pgd and init_mm.pgd is initialized at boot (instead of compile time) to the physmem virtual mapping of init_level4_pgd. The physical address changed. Except for the for EMPTY_ZERO page all of the remaining references to __pa_symbol appear to be during kernel initialization. So this should reduce the cost of __pa in the common case, even on a relocated kernel. As this is technically a semantic change we need to be on the lookout for anything I missed. But it works for me (tm). Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/x86_64/mm')
-rw-r--r--arch/x86_64/mm/init.c21
-rw-r--r--arch/x86_64/mm/pageattr.c16
2 files changed, 19 insertions, 18 deletions
diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index b0a60789218..69e22d3c923 100644
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -565,11 +565,11 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end)
printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10);
for (addr = begin; addr < end; addr += PAGE_SIZE) {
- ClearPageReserved(virt_to_page(addr));
- init_page_count(virt_to_page(addr));
- memset((void *)(addr & ~(PAGE_SIZE-1)),
- POISON_FREE_INITMEM, PAGE_SIZE);
- free_page(addr);
+ struct page *page = pfn_to_page(addr >> PAGE_SHIFT);
+ ClearPageReserved(page);
+ init_page_count(page);
+ memset(page_address(page), POISON_FREE_INITMEM, PAGE_SIZE);
+ __free_page(page);
totalram_pages++;
}
}
@@ -579,17 +579,18 @@ void free_initmem(void)
memset(__initdata_begin, POISON_FREE_INITDATA,
__initdata_end - __initdata_begin);
free_init_pages("unused kernel memory",
- (unsigned long)(&__init_begin),
- (unsigned long)(&__init_end));
+ __pa_symbol(&__init_begin),
+ __pa_symbol(&__init_end));
}
#ifdef CONFIG_DEBUG_RODATA
void mark_rodata_ro(void)
{
- unsigned long addr = (unsigned long)__start_rodata;
+ unsigned long addr = (unsigned long)__va(__pa_symbol(&__start_rodata));
+ unsigned long end = (unsigned long)__va(__pa_symbol(&__end_rodata));
- for (; addr < (unsigned long)__end_rodata; addr += PAGE_SIZE)
+ for (; addr < end; addr += PAGE_SIZE)
change_page_attr_addr(addr, 1, PAGE_KERNEL_RO);
printk ("Write protecting the kernel read-only data: %luk\n",
@@ -608,7 +609,7 @@ void mark_rodata_ro(void)
#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
- free_init_pages("initrd memory", start, end);
+ free_init_pages("initrd memory", __pa(start), __pa(end));
}
#endif
diff --git a/arch/x86_64/mm/pageattr.c b/arch/x86_64/mm/pageattr.c
index 081409aa345..76ee90a5abe 100644
--- a/arch/x86_64/mm/pageattr.c
+++ b/arch/x86_64/mm/pageattr.c
@@ -51,7 +51,6 @@ static struct page *split_large_page(unsigned long address, pgprot_t prot,
SetPagePrivate(base);
page_private(base) = 0;
- 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) {
@@ -101,13 +100,12 @@ static inline void save_page(struct page *fpage)
* No more special protections in this 2/4MB area - revert to a
* large page again.
*/
-static void revert_page(unsigned long address, pgprot_t ref_prot)
+static void revert_page(unsigned long address, unsigned long pfn, pgprot_t ref_prot)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t large_pte;
- unsigned long pfn;
pgd = pgd_offset_k(address);
BUG_ON(pgd_none(*pgd));
@@ -115,7 +113,6 @@ static void revert_page(unsigned long address, pgprot_t ref_prot)
BUG_ON(pud_none(*pud));
pmd = pmd_offset(pud, address);
BUG_ON(pmd_val(*pmd) & _PAGE_PSE);
- pfn = (__pa(address) & LARGE_PAGE_MASK) >> PAGE_SHIFT;
large_pte = pfn_pte(pfn, ref_prot);
large_pte = pte_mkhuge(large_pte);
set_pte((pte_t *)pmd, large_pte);
@@ -141,7 +138,8 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
*/
struct page *split;
ref_prot2 = pte_pgprot(pte_clrhuge(*kpte));
- split = split_large_page(address, prot, ref_prot2);
+ split = split_large_page(pfn << PAGE_SHIFT, prot,
+ ref_prot2);
if (!split)
return -ENOMEM;
set_pte(kpte, mk_pte(split, ref_prot2));
@@ -160,7 +158,7 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
if (page_private(kpte_page) == 0) {
save_page(kpte_page);
- revert_page(address, ref_prot);
+ revert_page(address, pfn, ref_prot);
}
return 0;
}
@@ -180,6 +178,7 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot,
*/
int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
{
+ unsigned long phys_base_pfn = __pa_symbol(__START_KERNEL_map) >> PAGE_SHIFT;
int err = 0;
int i;
@@ -192,10 +191,11 @@ int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot)
break;
/* Handle kernel mapping too which aliases part of the
* lowmem */
- if (__pa(address) < KERNEL_TEXT_SIZE) {
+ if ((pfn >= phys_base_pfn) &&
+ ((pfn - phys_base_pfn) < (KERNEL_TEXT_SIZE >> PAGE_SHIFT))) {
unsigned long addr2;
pgprot_t prot2;
- addr2 = __START_KERNEL_map + __pa(address);
+ addr2 = __START_KERNEL_map + ((pfn - phys_base_pfn) << PAGE_SHIFT);
/* Make sure the kernel mappings stay executable */
prot2 = pte_pgprot(pte_mkexec(pfn_pte(0, prot)));
err = __change_page_attr(addr2, pfn, prot2,