[patch 3/4] x86: PAT followup - Remove reserved pages mapping to zero page and not map them

venkatesh.pallipadi
2008-01-16T02:42:27Z

[-- Attachment #1: remove_reserved_zeropages.patch --]
[-- Type: text/plain, Size: 4429 bytes --]

Remove reserved pages mapping to zeropage. Reserved and holes are now not
mapped at all.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>

Index: linux-2.6.git/arch/x86/mm/init_32.c
===================================================================
--- linux-2.6.git.orig/arch/x86/mm/init_32.c 2008-01-15 11:02:23.000000000 -0800
+++ linux-2.6.git/arch/x86/mm/init_32.c 2008-01-15 11:08:29.000000000 -0800
@@ -143,50 +143,6 @@
return 0;
}

-static unsigned long __init get_res_page(void)
-{
- static unsigned long res_phys_page;
- if (!res_phys_page) {
-
- res_phys_page = (unsigned long)
- alloc_bootmem_low_pages(PAGE_SIZE);
- if (!res_phys_page)
- BUG();
-
- memset((char *)res_phys_page, 0xe, PAGE_SIZE);
- res_phys_page = __pa(res_phys_page);
- }
- return res_phys_page;
-}
-
-static unsigned long __init get_res_ptepage(void)
-{
- static unsigned long res_phys_ptepage;
- pte_t *pte;
- int pte_ofs;
- unsigned long pfn;
-
- if (!res_phys_ptepage) {
-
- res_phys_ptepage = (unsigned long)
- alloc_bootmem_low_pages(PAGE_SIZE);
- if (!res_phys_ptepage)
- BUG();
-
- paravirt_alloc_pt(&init_mm,
- __pa(res_phys_ptepage) >> PAGE_SHIFT);
-
- /* Set all PTEs in the range to zero page */
- pfn = get_res_page() >> PAGE_SHIFT;
- pte = (pte_t *)res_phys_ptepage;
- for (pte_ofs = 0; pte_ofs < PTRS_PER_PTE; pte++, pte_ofs++)
- set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
-
- res_phys_ptepage = __pa(res_phys_ptepage);
- }
- return res_phys_ptepage;
-}
-
/*
* This maps the physical memory to kernel virtual address space, a total
* of max_low_pfn pages, by creating page tables starting from address
@@ -199,7 +155,6 @@
pmd_t *pmd;
pte_t *pte;
int pgd_idx, pmd_idx, pte_ofs;
- unsigned long temp_pfn;

pgd_idx = pgd_index(PAGE_OFFSET);
pgd = pgd_base + pgd_idx;
@@ -238,9 +193,7 @@
}
if (cpu_has_pse &&
!is_memory_any_valid(paddr, paddr + PMD_SIZE)) {
-
- temp_pfn = get_res_ptepage();
- set_pmd(pmd, __pmd(temp_pfn | _PAGE_TABLE));
+ set_pmd(pmd, __pmd(0));
pfn += PTRS_PER_PTE;
continue;
}
@@ -259,10 +212,7 @@

if (!is_memory_any_valid(paddr,
paddr + PAGE_SIZE)) {
-
- temp_pfn = get_res_page() >> PAGE_SHIFT;
- set_pte(pte,
- pfn_pte(temp_pfn, PAGE_KERNEL));
+ set_pte(pte, __pte(0));
continue;
}

Index: linux-2.6.git/arch/x86/mm/init_64.c
===================================================================
--- linux-2.6.git.orig/arch/x86/mm/init_64.c 2008-01-15 11:06:37.000000000 -0800
+++ linux-2.6.git/arch/x86/mm/init_64.c 2008-01-15 11:09:18.000000000 -0800
@@ -494,41 +494,6 @@
kcore_vsyscall;

-static unsigned long __init get_res_page(void)
-{
- static unsigned long res_phys_page;
- if (!res_phys_page) {
- pte_t *pte;
- pte = alloc_low_page(&res_phys_page);
- unmap_low_page(pte);
- }
- return res_phys_page;
-}
-
-static unsigned long __init get_res_ptepage(void)
-{
- static unsigned long res_phys_ptepage;
- if (!res_phys_ptepage) {
- pte_t *pte_page;
- unsigned long page_phys;
- unsigned long entry;
- int i;
-
- pte_page = alloc_low_page(&res_phys_ptepage);
-
- page_phys = get_res_page();
- entry = _PAGE_NX | _KERNPG_TABLE | _PAGE_GLOBAL | page_phys;
- entry &= __supported_pte_mask;
- for (i = 0; i < PTRS_PER_PTE; i++) {
- pte_t *pte = pte_page + i;
- set_pte(pte, __pte(entry));
- }
-
- unmap_low_page(pte_page);
- }
- return res_phys_ptepage;
-}
-
static void __init phys_pte_prune(pte_t *pte_page, unsigned long address,
unsigned long end, unsigned long vaddr, unsigned int exec)
{
@@ -545,15 +510,7 @@
if (!(address & (~PAGE_MASK)) &&
(address + PAGE_SIZE <= end) &&
!is_memory_any_valid(address, address + PAGE_SIZE)) {
- unsigned long phys_page;
-
- phys_page = get_res_page();
- entry = _PAGE_NX | _KERNPG_TABLE | _PAGE_GLOBAL |
- phys_page;
-
- entry &= __supported_pte_mask;
- set_pte(pte, __pte(entry));
-
+ set_pte(pte, __pte(0));
continue;
}

@@ -587,10 +544,7 @@
if (!(address & (~PMD_MASK)) &&
(address + PMD_SIZE <= end) &&
!is_memory_any_valid(address, address + PMD_SIZE)) {
-
- pte_phys = get_res_ptepage();
- set_pmd(pmd, __pmd(pte_phys | _KERNPG_TABLE));
-
+ set_pmd(pmd, __pmd(0));
continue;
}

--