MIPS: Limit fixrange_init() to the FIXMAP region

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>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1980/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 11689e1a292459a2eca9c7a8ea21047fb08c3a5f..b7ebc4fa89bcd5b4b77465ab60919317b513bf79 100644 (file)
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -277,11 +277,11 @@ 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 575e4019227b0916d649b108165f2d05812660a5..adc6911ba748915bda5b2575fc03b76891f1fb21 100644 (file)
--- 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 78eaa4f0b0eccd4980ad1fa692343e76e50e63e3..cda4e300eb0a8c2edb6eb205debd06810e4fff9d 100644 (file)
--- 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);
 }