x86: clean up dead code in vmi_32.c

Impact: cleanup, remove dead debug code

I ran across some old debugging code in vmi paravirt-ops code that was
already dead, but still potentially useful.  After reviewing recent
changes to the way kernel page tables are allocated and initialized, and
the lack of bugs caught by this debugging code, I've concluded it is now
totally useless to have around, and it's already been #if 0'd for quite
some time.

There's no rush to get this in mainline, but it's also totally harmless,
so I'll let the x86 maintainers decide where it should be tucked.  I've
been out of the mainstream dev loop for a couple months, so apologies if
I haven't got any protocol changes in order.

Remove mummified remains found in vmi_32.c

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/vmi_32.c

@@ -266,109 +266,6 @@ static void vmi_nop(void)
 {
 }
 
-#ifdef CONFIG_DEBUG_PAGE_TYPE
-
-#ifdef CONFIG_X86_PAE
-#define MAX_BOOT_PTS (2048+4+1)
-#else
-#define MAX_BOOT_PTS (1024+1)
-#endif
-
-/*
- * During boot, mem_map is not yet available in paging_init, so stash
- * all the boot page allocations here.
- */
-static struct {
-	u32 pfn;
-	int type;
-} boot_page_allocations[MAX_BOOT_PTS];
-static int num_boot_page_allocations;
-static int boot_allocations_applied;
-
-void vmi_apply_boot_page_allocations(void)
-{
-	int i;
-	BUG_ON(!mem_map);
-	for (i = 0; i < num_boot_page_allocations; i++) {
-		struct page *page = pfn_to_page(boot_page_allocations[i].pfn);
-		page->type = boot_page_allocations[i].type;
-		page->type = boot_page_allocations[i].type &
-				~(VMI_PAGE_ZEROED | VMI_PAGE_CLONE);
-	}
-	boot_allocations_applied = 1;
-}
-
-static void record_page_type(u32 pfn, int type)
-{
-	BUG_ON(num_boot_page_allocations >= MAX_BOOT_PTS);
-	boot_page_allocations[num_boot_page_allocations].pfn = pfn;
-	boot_page_allocations[num_boot_page_allocations].type = type;
-	num_boot_page_allocations++;
-}
-
-static void check_zeroed_page(u32 pfn, int type, struct page *page)
-{
-	u32 *ptr;
-	int i;
-	int limit = PAGE_SIZE / sizeof(int);
-
-	if (page_address(page))
-		ptr = (u32 *)page_address(page);
-	else
-		ptr = (u32 *)__va(pfn << PAGE_SHIFT);
-	/*
-	 * When cloning the root in non-PAE mode, only the userspace
-	 * pdes need to be zeroed.
-	 */
-	if (type & VMI_PAGE_CLONE)
-		limit = KERNEL_PGD_BOUNDARY;
-	for (i = 0; i < limit; i++)
-		BUG_ON(ptr[i]);
-}
-
-/*
- * We stash the page type into struct page so we can verify the page
- * types are used properly.
- */
-static void vmi_set_page_type(u32 pfn, int type)
-{
-	/* PAE can have multiple roots per page - don't track */
-	if (PTRS_PER_PMD > 1 && (type & VMI_PAGE_PDP))
-		return;
-
-	if (boot_allocations_applied) {
-		struct page *page = pfn_to_page(pfn);
-		if (type != VMI_PAGE_NORMAL)
-			BUG_ON(page->type);
-		else
-			BUG_ON(page->type == VMI_PAGE_NORMAL);
-		page->type = type & ~(VMI_PAGE_ZEROED | VMI_PAGE_CLONE);
-		if (type & VMI_PAGE_ZEROED)
-			check_zeroed_page(pfn, type, page);
-	} else {
-		record_page_type(pfn, type);
-	}
-}
-
-static void vmi_check_page_type(u32 pfn, int type)
-{
-	/* PAE can have multiple roots per page - skip checks */
-	if (PTRS_PER_PMD > 1 && (type & VMI_PAGE_PDP))
-		return;
-
-	type &= ~(VMI_PAGE_ZEROED | VMI_PAGE_CLONE);
-	if (boot_allocations_applied) {
-		struct page *page = pfn_to_page(pfn);
-		BUG_ON((page->type ^ type) & VMI_PAGE_PAE);
-		BUG_ON(type == VMI_PAGE_NORMAL && page->type);
-		BUG_ON((type & page->type) == 0);
-	}
-}
-#else
-#define vmi_set_page_type(p,t) do { } while (0)
-#define vmi_check_page_type(p,t) do { } while (0)
-#endif
-
 #ifdef CONFIG_HIGHPTE
 static void *vmi_kmap_atomic_pte(struct page *page, enum km_type type)
 {
@@ -395,7 +292,6 @@ static void *vmi_kmap_atomic_pte(struct page *page, enum km_type type)
 
 static void vmi_allocate_pte(struct mm_struct *mm, unsigned long pfn)
 {
-	vmi_set_page_type(pfn, VMI_PAGE_L1);
 	vmi_ops.allocate_page(pfn, VMI_PAGE_L1, 0, 0, 0);
 }
 
@@ -406,27 +302,22 @@ static void vmi_allocate_pmd(struct mm_struct *mm, unsigned long pfn)
 	 * It is called only for swapper_pg_dir, which already has
 	 * data on it.
 	 */
- 	vmi_set_page_type(pfn, VMI_PAGE_L2);
 	vmi_ops.allocate_page(pfn, VMI_PAGE_L2, 0, 0, 0);
 }
 
 static void vmi_allocate_pmd_clone(unsigned long pfn, unsigned long clonepfn, unsigned long start, unsigned long count)
 {
- 	vmi_set_page_type(pfn, VMI_PAGE_L2 | VMI_PAGE_CLONE);
-	vmi_check_page_type(clonepfn, VMI_PAGE_L2);
 	vmi_ops.allocate_page(pfn, VMI_PAGE_L2 | VMI_PAGE_CLONE, clonepfn, start, count);
 }
 
 static void vmi_release_pte(unsigned long pfn)
 {
 	vmi_ops.release_page(pfn, VMI_PAGE_L1);
-	vmi_set_page_type(pfn, VMI_PAGE_NORMAL);
 }
 
 static void vmi_release_pmd(unsigned long pfn)
 {
 	vmi_ops.release_page(pfn, VMI_PAGE_L2);
-	vmi_set_page_type(pfn, VMI_PAGE_NORMAL);
 }
 
 /*
@@ -450,26 +341,22 @@ static void vmi_release_pmd(unsigned long pfn)
 
 static void vmi_update_pte(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
-	vmi_check_page_type(__pa(ptep) >> PAGE_SHIFT, VMI_PAGE_PTE);
 	vmi_ops.update_pte(ptep, vmi_flags_addr(mm, addr, VMI_PAGE_PT, 0));
 }
 
 static void vmi_update_pte_defer(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
-	vmi_check_page_type(__pa(ptep) >> PAGE_SHIFT, VMI_PAGE_PTE);
 	vmi_ops.update_pte(ptep, vmi_flags_addr_defer(mm, addr, VMI_PAGE_PT, 0));
 }
 
 static void vmi_set_pte(pte_t *ptep, pte_t pte)
 {
 	/* XXX because of set_pmd_pte, this can be called on PT or PD layers */
-	vmi_check_page_type(__pa(ptep) >> PAGE_SHIFT, VMI_PAGE_PTE | VMI_PAGE_PD);
 	vmi_ops.set_pte(pte, ptep, VMI_PAGE_PT);
 }
 
 static void vmi_set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte)
 {
-	vmi_check_page_type(__pa(ptep) >> PAGE_SHIFT, VMI_PAGE_PTE);
 	vmi_ops.set_pte(pte, ptep, vmi_flags_addr(mm, addr, VMI_PAGE_PT, 0));
 }
 
@@ -477,10 +364,8 @@ static void vmi_set_pmd(pmd_t *pmdp, pmd_t pmdval)
 {
 #ifdef CONFIG_X86_PAE
 	const pte_t pte = { .pte = pmdval.pmd };
-	vmi_check_page_type(__pa(pmdp) >> PAGE_SHIFT, VMI_PAGE_PMD);
 #else
 	const pte_t pte = { pmdval.pud.pgd.pgd };
-	vmi_check_page_type(__pa(pmdp) >> PAGE_SHIFT, VMI_PAGE_PGD);
 #endif
 	vmi_ops.set_pte(pte, (pte_t *)pmdp, VMI_PAGE_PD);
 }
@@ -502,7 +387,6 @@ static void vmi_set_pte_atomic(pte_t *ptep, pte_t pteval)
 
 static void vmi_set_pte_present(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte)
 {
-	vmi_check_page_type(__pa(ptep) >> PAGE_SHIFT, VMI_PAGE_PTE);
 	vmi_ops.set_pte(pte, ptep, vmi_flags_addr_defer(mm, addr, VMI_PAGE_PT, 1));
 }
 
@@ -510,21 +394,18 @@ static void vmi_set_pud(pud_t *pudp, pud_t pudval)
 {
 	/* Um, eww */
 	const pte_t pte = { .pte = pudval.pgd.pgd };
-	vmi_check_page_type(__pa(pudp) >> PAGE_SHIFT, VMI_PAGE_PGD);
 	vmi_ops.set_pte(pte, (pte_t *)pudp, VMI_PAGE_PDP);
 }
 
 static void vmi_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
 	const pte_t pte = { .pte = 0 };
-	vmi_check_page_type(__pa(ptep) >> PAGE_SHIFT, VMI_PAGE_PTE);
 	vmi_ops.set_pte(pte, ptep, vmi_flags_addr(mm, addr, VMI_PAGE_PT, 0));
 }
 
 static void vmi_pmd_clear(pmd_t *pmd)
 {
 	const pte_t pte = { .pte = 0 };
-	vmi_check_page_type(__pa(pmd) >> PAGE_SHIFT, VMI_PAGE_PMD);
 	vmi_ops.set_pte(pte, (pte_t *)pmd, VMI_PAGE_PD);
 }
 #endif