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[PATCH 6/6] MIPS: Limit fixrange_init() to the FIXMAP region

To: Ralf Baechle <ralf@linux-mips.org>
Subject: [PATCH 6/6] MIPS: Limit fixrange_init() to the FIXMAP region
From: Kevin Cernekee <cernekee@gmail.com>
Date: Wed, 05 Jan 2011 23:31:30 -0800
Cc: <linux-mips@linux-mips.org>, <linux-kernel@vger.kernel.org>
In-reply-to: <8eec0c63f92528c501c0e6a0c8396359@localhost>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <8eec0c63f92528c501c0e6a0c8396359@localhost>
Sender: linux-mips-bounce@linux-mips.org
User-agent: vim 7.2
fixrange_init() allocates page tables for all addresses higher than
FIXADDR_TOP.  On processors that override the default FIXADDR_TOP
address of 0xfffe_0000, this can consume up to 4 pages (1 page per 4MB)
for pgd's that are never used.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
---
 arch/mips/mm/init.c       |    6 +++---
 arch/mips/mm/pgtable-32.c |    2 +-
 arch/mips/mm/pgtable-64.c |    2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 2efcbd2..deb8b3a 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -279,11 +279,11 @@ void __init fixrange_init(unsigned long start, unsigned 
long end,
        k = __pmd_offset(vaddr);
        pgd = pgd_base + i;
 
-       for ( ; (i < PTRS_PER_PGD) && (vaddr != end); pgd++, i++) {
+       for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
                pud = (pud_t *)pgd;
-               for ( ; (j < PTRS_PER_PUD) && (vaddr != end); pud++, j++) {
+               for ( ; (j < PTRS_PER_PUD) && (vaddr < end); pud++, j++) {
                        pmd = (pmd_t *)pud;
-                       for (; (k < PTRS_PER_PMD) && (vaddr != end); pmd++, 
k++) {
+                       for (; (k < PTRS_PER_PMD) && (vaddr < end); pmd++, k++) 
{
                                if (pmd_none(*pmd)) {
                                        pte = (pte_t *) 
alloc_bootmem_low_pages(PAGE_SIZE);
                                        set_pmd(pmd, __pmd((unsigned long)pte));
diff --git a/arch/mips/mm/pgtable-32.c b/arch/mips/mm/pgtable-32.c
index 575e401..adc6911 100644
--- a/arch/mips/mm/pgtable-32.c
+++ b/arch/mips/mm/pgtable-32.c
@@ -52,7 +52,7 @@ void __init pagetable_init(void)
         * Fixed mappings:
         */
        vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
-       fixrange_init(vaddr, 0, pgd_base);
+       fixrange_init(vaddr, vaddr + FIXADDR_SIZE, pgd_base);
 
 #ifdef CONFIG_HIGHMEM
        /*
diff --git a/arch/mips/mm/pgtable-64.c b/arch/mips/mm/pgtable-64.c
index 78eaa4f..cda4e30 100644
--- a/arch/mips/mm/pgtable-64.c
+++ b/arch/mips/mm/pgtable-64.c
@@ -76,5 +76,5 @@ void __init pagetable_init(void)
         * Fixed mappings:
         */
        vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
-       fixrange_init(vaddr, 0, pgd_base);
+       fixrange_init(vaddr, vaddr + FIXADDR_SIZE, pgd_base);
 }
-- 
1.7.0.4


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