[PATCH] x86: cleanup dump_pagetable()

From: Akinobu Mita
Date: Sat Jun 27 2009 - 02:37:38 EST


Use pgtable access helpers for 32bit version dump_pagetable() and get rid
of __typeof__() operators. This needs to make pmd_pfn() available for 2-level
pgtable.

Also, remove some casts for 64bit version dump_pagetable().

Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
---
arch/x86/include/asm/pgtable.h | 10 ++++----
arch/x86/mm/fault.c | 51 ++++++++++++++++-----------------------
2 files changed, 26 insertions(+), 35 deletions(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 3cc06e3..af5481e 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -134,6 +134,11 @@ static inline unsigned long pte_pfn(pte_t pte)
return (pte_val(pte) & PTE_PFN_MASK) >> PAGE_SHIFT;
}

+static inline unsigned long pmd_pfn(pmd_t pmd)
+{
+ return (pmd_val(pmd) & PTE_PFN_MASK) >> PAGE_SHIFT;
+}
+
#define pte_page(pte) pfn_to_page(pte_pfn(pte))

static inline int pmd_large(pmd_t pte)
@@ -422,11 +427,6 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address);
}

-static inline unsigned long pmd_pfn(pmd_t pmd)
-{
- return (pmd_val(pmd) & PTE_PFN_MASK) >> PAGE_SHIFT;
-}
-
static inline int pud_large(pud_t pud)
{
return (pud_val(pud) & (_PAGE_PSE | _PAGE_PRESENT)) ==
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 78a5fff..9bf7e52 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -285,26 +285,25 @@ check_v8086_mode(struct pt_regs *regs, unsigned long address,
tsk->thread.screen_bitmap |= 1 << bit;
}

-static void dump_pagetable(unsigned long address)
+static bool low_pfn(unsigned long pfn)
{
- __typeof__(pte_val(__pte(0))) page;
+ return pfn < max_low_pfn;
+}

- page = read_cr3();
- page = ((__typeof__(page) *) __va(page))[address >> PGDIR_SHIFT];
+static void dump_pagetable(unsigned long address)
+{
+ pgd_t *base = __va(read_cr3());
+ pgd_t *pgd = &base[pgd_index(address)];
+ pmd_t *pmd;
+ pte_t *pte;

#ifdef CONFIG_X86_PAE
- printk("*pdpt = %016Lx ", page);
- if ((page >> PAGE_SHIFT) < max_low_pfn
- && page & _PAGE_PRESENT) {
- page &= PAGE_MASK;
- page = ((__typeof__(page) *) __va(page))[(address >> PMD_SHIFT)
- & (PTRS_PER_PMD - 1)];
- printk(KERN_CONT "*pde = %016Lx ", page);
- page &= ~_PAGE_NX;
- }
-#else
- printk("*pde = %08lx ", page);
+ printk("*pdpt = %016Lx ", pgd_val(*pgd));
+ if (!low_pfn(pgd_val(*pgd) >> PAGE_SHIFT) || !pgd_present(*pgd))
+ goto out;
#endif
+ pmd = pmd_offset(pud_offset(pgd, address), address);
+ printk(KERN_CONT "*pde = %0*Lx ", sizeof(*pmd) * 2, (u64)pmd_val(*pmd));

/*
* We must not directly access the pte in the highpte
@@ -312,16 +311,12 @@ static void dump_pagetable(unsigned long address)
* And let's rather not kmap-atomic the pte, just in case
* it's allocated already:
*/
- if ((page >> PAGE_SHIFT) < max_low_pfn
- && (page & _PAGE_PRESENT)
- && !(page & _PAGE_PSE)) {
-
- page &= PAGE_MASK;
- page = ((__typeof__(page) *) __va(page))[(address >> PAGE_SHIFT)
- & (PTRS_PER_PTE - 1)];
- printk("*pte = %0*Lx ", sizeof(page)*2, (u64)page);
- }
+ if (!low_pfn(pmd_pfn(*pmd)) || !pmd_present(*pmd) || pmd_large(*pmd))
+ goto out;

+ pte = pte_offset_kernel(pmd, address);
+ printk("*pte = %0*Lx ", sizeof(*pte) * 2, (u64)pte_val(*pte));
+out:
printk("\n");
}

@@ -449,16 +444,12 @@ static int bad_address(void *p)

static void dump_pagetable(unsigned long address)
{
- pgd_t *pgd;
+ pgd_t *base = __va(read_cr3() & PHYSICAL_PAGE_MASK);
+ pgd_t *pgd = base + pgd_index(address);
pud_t *pud;
pmd_t *pmd;
pte_t *pte;

- pgd = (pgd_t *)read_cr3();
-
- pgd = __va((unsigned long)pgd & PHYSICAL_PAGE_MASK);
-
- pgd += pgd_index(address);
if (bad_address(pgd))
goto bad;

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