Re: [PATCH] i386: For debugging, make the initial page table setup less forgiving.

Jeremy Fitzhardinge
2007-04-25T22:08:28Z

Eric W. Biederman wrote:
> Nope. It's not overwriting anything.

This should fix it.

Subject: x86: fix PSE pagetable construction

When constructing the initial pagetable in pagetable_init, make sure
that non-PSE pmds are updated to PSE ones.

This moves the definition of pmd_huge() out of the hugetlbfs files
into pgtable.h.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>

---
arch/i386/mm/hugetlbpage.c | 6 +-----
arch/i386/mm/init.c | 2 +-
include/asm-i386/pgtable.h | 2 +-
include/asm-x86_64/pgtable.h | 1 +
include/linux/hugetlb.h | 2 --
5 files changed, 4 insertions(+), 9 deletions(-)

===================================================================
--- a/arch/i386/mm/hugetlbpage.c
+++ b/arch/i386/mm/hugetlbpage.c
@@ -183,6 +183,7 @@ follow_huge_addr(struct mm_struct *mm, u
return page;
}

+#undef pmd_huge
int pmd_huge(pmd_t pmd)
{
return 0;
@@ -201,11 +202,6 @@ follow_huge_addr(struct mm_struct *mm, u
follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
{
return ERR_PTR(-EINVAL);
-}
-
-int pmd_huge(pmd_t pmd)
-{
- return !!(pmd_val(pmd) & _PAGE_PSE);
}

struct page *
===================================================================
--- a/arch/i386/mm/init.c
+++ b/arch/i386/mm/init.c
@@ -172,7 +172,7 @@ static void __init kernel_physical_mappi
/* Map with big pages if possible, otherwise create normal page tables. */
if (cpu_has_pse) {
unsigned int address2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1;
- if (!pmd_present(*pmd)) {
+ if (!pmd_present(*pmd) || !pmd_huge(*pmd)) {
if (is_kernel_text(address) || is_kernel_text(address2))
set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
else
===================================================================
--- a/include/asm-i386/pgtable.h
+++ b/include/asm-i386/pgtable.h
@@ -211,7 +211,7 @@ extern unsigned long pg0[];
#define pmd_none(x) (!(unsigned long)pmd_val(x))
#define pmd_present(x) (pmd_val(x) & _PAGE_PRESENT)
#define pmd_bad(x) ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)
-
+#define pmd_huge(x) ((pmd_val(x) & _PAGE_PSE) != 0)

#define pages_to_mb(x) ((x) >> (20-PAGE_SHIFT))

===================================================================
--- a/include/asm-x86_64/pgtable.h
+++ b/include/asm-x86_64/pgtable.h
@@ -352,6 +352,7 @@ static inline int pmd_large(pmd_t pte) {
pmd_index(address))
#define pmd_none(x) (!pmd_val(x))
#define pmd_present(x) (pmd_val(x) & _PAGE_PRESENT)
+#define pmd_huge(x) ((pmd_val(x) & _PAGE_PSE) != 0)
#define pmd_clear(xp) do { set_pmd(xp, __pmd(0)); } while (0)
#define pfn_pmd(nr,prot) (__pmd(((nr) << PAGE_SHIFT) | pgprot_val(prot)))
#define pmd_pfn(x) ((pmd_val(x) & __PHYSICAL_MASK) >> PAGE_SHIFT)
===================================================================
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -41,7 +41,6 @@ struct page *follow_huge_addr(struct mm_
int write);
struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
pmd_t *pmd, int write);
-int pmd_huge(pmd_t pmd);
void hugetlb_change_protection(struct vm_area_struct *vma,
unsigned long address, unsigned long end, pgprot_t newprot);

@@ -114,7 +113,6 @@ static inline unsigned long hugetlb_tota
#define hugetlb_report_node_meminfo(n, buf) 0
#define follow_huge_pmd(mm, addr, pmd, write) NULL
#define prepare_hugepage_range(addr,len,pgoff) (-EINVAL)
-#define pmd_huge(x) 0
#define is_hugepage_only_range(mm, addr, len) 0
#define hugetlb_free_pgd_range(tlb, addr, end, floor, ceiling) ({BUG(); 0; })
#define hugetlb_fault(mm, vma, addr, write) ({ BUG(); 0; })