1 files changed, 18 insertions, 17 deletions

diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index ee1091a46964..1500dc8d63e4 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -51,6 +51,8 @@
 
 unsigned int __VMALLOC_RESERVE = 128 << 20;
 
+unsigned long max_pfn_mapped;
+
 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
 unsigned long highstart_pfn, highend_pfn;
 
@@ -179,8 +181,13 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
                         /*
                          * Map with big pages if possible, otherwise
                          * create normal page tables:
+                         *
+                         * Don't use a large page for the first 2/4MB of memory
+                         * because there are often fixed size MTRRs in there
+                         * and overlapping MTRRs into large pages can cause
+                         * slowdowns.
                          */
-                        if (cpu_has_pse) {
+                        if (cpu_has_pse && !(pgd_idx == 0 && pmd_idx == 0)) {
                                 unsigned int addr2;
                                 pgprot_t prot = PAGE_KERNEL_LARGE;
 
@@ -194,6 +201,7 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
                                 set_pmd(pmd, pfn_pmd(pfn, prot));
 
                                 pfn += PTRS_PER_PTE;
+                                max_pfn_mapped = pfn;
                                 continue;
                         }
                         pte = one_page_table_init(pmd);
@@ -208,6 +216,7 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
 
                                 set_pte(pte, pfn_pte(pfn, prot));
                         }
+                        max_pfn_mapped = pfn;
                 }
         }
 }
@@ -723,25 +732,17 @@ void mark_rodata_ro(void)
         unsigned long start = PFN_ALIGN(_text);
         unsigned long size = PFN_ALIGN(_etext) - start;
 
-#ifndef CONFIG_KPROBES
-#ifdef CONFIG_HOTPLUG_CPU
-        /* It must still be possible to apply SMP alternatives. */
-        if (num_possible_cpus() <= 1)
-#endif
-        {
-                set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
-                printk(KERN_INFO "Write protecting the kernel text: %luk\n",
-                        size >> 10);
+        set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
+        printk(KERN_INFO "Write protecting the kernel text: %luk\n",
+                size >> 10);
 
 #ifdef CONFIG_CPA_DEBUG
-                printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
-                        start, start+size);
-                set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
+        printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
+                start, start+size);
+        set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
 
-                printk(KERN_INFO "Testing CPA: write protecting again\n");
-                set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
-#endif
-        }
+        printk(KERN_INFO "Testing CPA: write protecting again\n");
+        set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
 #endif
         start += size;
         size = (unsigned long)__end_rodata - start;