linux-kernel - [PATCH 22/46] x86, mm: Remove early_memremap workaround for page table accessing on 64bit

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Message-Id: <1352755122-25660-23-git-send-email-yinghai@kernel.org>
Date:	Mon, 12 Nov 2012 13:18:18 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
	"H. Peter Anvin" <hpa@...or.com>, Jacob Shin <jacob.shin@....com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Stefano Stabellini <stefano.stabellini@...citrix.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	linux-kernel@...r.kernel.org, Yinghai Lu <yinghai@...nel.org>
Subject: [PATCH 22/46] x86, mm: Remove early_memremap workaround for page table accessing on 64bit

We try to put page table high to make room for kdump, and at that time
those ranges are not mapped yet, and have to use ioremap to access it.

Now after patch that pre-map page table top down.
	x86, mm: setup page table in top-down
We do not need that workaround anymore.

Just use __va to return directly mapping address.

Signed-off-by: Yinghai Lu <yinghai@...nel.org>
---
 arch/x86/mm/init_64.c |   38 ++++----------------------------------
 1 files changed, 4 insertions(+), 34 deletions(-)

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index eefaea6..5ee9242 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -340,36 +340,12 @@ static __ref void *alloc_low_page(unsigned long *phys)
 	} else
 		pfn = pgt_buf_end++;
 
-	adr = early_memremap(pfn * PAGE_SIZE, PAGE_SIZE);
+	adr = __va(pfn * PAGE_SIZE);
 	clear_page(adr);
 	*phys  = pfn * PAGE_SIZE;
 	return adr;
 }
 
-static __ref void *map_low_page(void *virt)
-{
-	void *adr;
-	unsigned long phys, left;
-
-	if (after_bootmem)
-		return virt;
-
-	phys = __pa(virt);
-	left = phys & (PAGE_SIZE - 1);
-	adr = early_memremap(phys & PAGE_MASK, PAGE_SIZE);
-	adr = (void *)(((unsigned long)adr) | left);
-
-	return adr;
-}
-
-static __ref void unmap_low_page(void *adr)
-{
-	if (after_bootmem)
-		return;
-
-	early_iounmap((void *)((unsigned long)adr & PAGE_MASK), PAGE_SIZE);
-}
-
 static unsigned long __meminit
 phys_pte_init(pte_t *pte_page, unsigned long addr, unsigned long end,
 	      pgprot_t prot)
@@ -442,10 +418,9 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end,
 		if (pmd_val(*pmd)) {
 			if (!pmd_large(*pmd)) {
 				spin_lock(&init_mm.page_table_lock);
-				pte = map_low_page((pte_t *)pmd_page_vaddr(*pmd));
+				pte = (pte_t *)pmd_page_vaddr(*pmd);
 				last_map_addr = phys_pte_init(pte, address,
 								end, prot);
-				unmap_low_page(pte);
 				spin_unlock(&init_mm.page_table_lock);
 				continue;
 			}
@@ -483,7 +458,6 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end,
 
 		pte = alloc_low_page(&pte_phys);
 		last_map_addr = phys_pte_init(pte, address, end, new_prot);
-		unmap_low_page(pte);
 
 		spin_lock(&init_mm.page_table_lock);
 		pmd_populate_kernel(&init_mm, pmd, __va(pte_phys));
@@ -518,10 +492,9 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end,
 
 		if (pud_val(*pud)) {
 			if (!pud_large(*pud)) {
-				pmd = map_low_page(pmd_offset(pud, 0));
+				pmd = pmd_offset(pud, 0);
 				last_map_addr = phys_pmd_init(pmd, addr, end,
 							 page_size_mask, prot);
-				unmap_low_page(pmd);
 				__flush_tlb_all();
 				continue;
 			}
@@ -560,7 +533,6 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end,
 		pmd = alloc_low_page(&pmd_phys);
 		last_map_addr = phys_pmd_init(pmd, addr, end, page_size_mask,
 					      prot);
-		unmap_low_page(pmd);
 
 		spin_lock(&init_mm.page_table_lock);
 		pud_populate(&init_mm, pud, __va(pmd_phys));
@@ -596,17 +568,15 @@ kernel_physical_mapping_init(unsigned long start,
 			next = end;
 
 		if (pgd_val(*pgd)) {
-			pud = map_low_page((pud_t *)pgd_page_vaddr(*pgd));
+			pud = (pud_t *)pgd_page_vaddr(*pgd);
 			last_map_addr = phys_pud_init(pud, __pa(start),
 						 __pa(end), page_size_mask);
-			unmap_low_page(pud);
 			continue;
 		}
 
 		pud = alloc_low_page(&pud_phys);
 		last_map_addr = phys_pud_init(pud, __pa(start), __pa(next),
 						 page_size_mask);
-		unmap_low_page(pud);
 
 		spin_lock(&init_mm.page_table_lock);
 		pgd_populate(&init_mm, pgd, __va(pud_phys));
-- 
1.7.7

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