x86: memory corruption check - cleanup

[linux-2.6-omap-h63xx.git] / arch / x86 / mm / init_32.c

diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 6b9a9358b3308e9fc4972275b60f7e3b35b12d63..bbe044dbe01403b0bdf67dbf4fe7e46e4e00a07e 100644 (file)
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -31,6 +31,7 @@
 #include <linux/cpumask.h>
 
 #include <asm/asm.h>
+#include <asm/bios_ebda.h>
 #include <asm/processor.h>
 #include <asm/system.h>
 #include <asm/uaccess.h>
@@ -195,11 +196,30 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
        pgd_t *pgd;
        pmd_t *pmd;
        pte_t *pte;
-       unsigned pages_2m = 0, pages_4k = 0;
+       unsigned pages_2m, pages_4k;
+       int mapping_iter;
+
+       /*
+        * First iteration will setup identity mapping using large/small pages
+        * based on use_pse, with other attributes same as set by
+        * the early code in head_32.S
+        *
+        * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
+        * as desired for the kernel identity mapping.
+        *
+        * This two pass mechanism conforms to the TLB app note which says:
+        *
+        *     "Software should not write to a paging-structure entry in a way
+        *      that would change, for any linear address, both the page size
+        *      and either the page frame or attributes."
+        */
+       mapping_iter = 1;
 
        if (!cpu_has_pse)
                use_pse = 0;
 
+repeat:
+       pages_2m = pages_4k = 0;
        pfn = start_pfn;
        pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
        pgd = pgd_base + pgd_idx;
@@ -225,6 +245,13 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
                        if (use_pse) {
                                unsigned int addr2;
                                pgprot_t prot = PAGE_KERNEL_LARGE;
+                               /*
+                                * first pass will use the same initial
+                                * identity mapping attribute + _PAGE_PSE.
+                                */
+                               pgprot_t init_prot =
+                                       __pgprot(PTE_IDENT_ATTR |
+                                                _PAGE_PSE);
 
                                addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
                                        PAGE_OFFSET + PAGE_SIZE-1;
@@ -234,7 +261,10 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
                                        prot = PAGE_KERNEL_LARGE_EXEC;
 
                                pages_2m++;
-                               set_pmd(pmd, pfn_pmd(pfn, prot));
+                               if (mapping_iter == 1)
+                                       set_pmd(pmd, pfn_pmd(pfn, init_prot));
+                               else
+                                       set_pmd(pmd, pfn_pmd(pfn, prot));
 
                                pfn += PTRS_PER_PTE;
                                continue;
@@ -246,17 +276,43 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
                        for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
                             pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
                                pgprot_t prot = PAGE_KERNEL;
+                               /*
+                                * first pass will use the same initial
+                                * identity mapping attribute.
+                                */
+                               pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
 
                                if (is_kernel_text(addr))
                                        prot = PAGE_KERNEL_EXEC;
 
                                pages_4k++;
-                               set_pte(pte, pfn_pte(pfn, prot));
+                               if (mapping_iter == 1)
+                                       set_pte(pte, pfn_pte(pfn, init_prot));
+                               else
+                                       set_pte(pte, pfn_pte(pfn, prot));
                        }
                }
        }
-       update_page_count(PG_LEVEL_2M, pages_2m);
-       update_page_count(PG_LEVEL_4K, pages_4k);
+       if (mapping_iter == 1) {
+               /*
+                * update direct mapping page count only in the first
+                * iteration.
+                */
+               update_page_count(PG_LEVEL_2M, pages_2m);
+               update_page_count(PG_LEVEL_4K, pages_4k);
+
+               /*
+                * local global flush tlb, which will flush the previous
+                * mappings present in both small and large page TLB's.
+                */
+               __flush_tlb_all();
+
+               /*
+                * Second iteration will set the actual desired PTE attributes.
+                */
+               mapping_iter = 2;
+               goto repeat;
+       }
 }
 
 /*
@@ -719,7 +775,7 @@ void __init setup_bootmem_allocator(void)
        after_init_bootmem = 1;
 }
 
-static void __init find_early_table_space(unsigned long end)
+static void __init find_early_table_space(unsigned long end, int use_pse)
 {
        unsigned long puds, pmds, ptes, tables, start;
 
@@ -729,7 +785,7 @@ static void __init find_early_table_space(unsigned long end)
        pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
        tables += PAGE_ALIGN(pmds * sizeof(pmd_t));
 
-       if (cpu_has_pse) {
+       if (use_pse) {
                unsigned long extra;
 
                extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
@@ -769,12 +825,22 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
        pgd_t *pgd_base = swapper_pg_dir;
        unsigned long start_pfn, end_pfn;
        unsigned long big_page_start;
+#ifdef CONFIG_DEBUG_PAGEALLOC
+       /*
+        * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
+        * This will simplify cpa(), which otherwise needs to support splitting
+        * large pages into small in interrupt context, etc.
+        */
+       int use_pse = 0;
+#else
+       int use_pse = cpu_has_pse;
+#endif
 
        /*
         * Find space for the kernel direct mapping tables.
         */
        if (!after_init_bootmem)
-               find_early_table_space(end);
+               find_early_table_space(end, use_pse);
 
 #ifdef CONFIG_X86_PAE
        set_nx();
@@ -820,7 +886,7 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
        end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
        if (start_pfn < end_pfn)
                kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
-                                               cpu_has_pse);
+                                            use_pse);
 
        /* tail is not big page alignment ? */
        start_pfn = end_pfn;
@@ -904,6 +970,8 @@ void __init mem_init(void)
        int codesize, reservedpages, datasize, initsize;
        int tmp;
 
+       start_periodic_check_for_corruption();
+
 #ifdef CONFIG_FLATMEM
        BUG_ON(!mem_map);
 #endif
@@ -983,7 +1051,6 @@ void __init mem_init(void)
        if (boot_cpu_data.wp_works_ok < 0)
                test_wp_bit();
 
-       cpa_init();
        save_pg_dir();
        zap_low_mappings();
 }