Revert "x86: Cleanup highmap after brk is concluded"

BugLink: http://bugs.launchpad.net/bugs/761134

This reverts upstream commit e5f15b45ddf3afa2bbbb10c7ea34fb32b6de0a0e

It caused problems in the stable tree and should not have been there.

Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 5655c22..2d2673c 100644 (file)
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -77,6 +77,9 @@ void __init x86_64_start_kernel(char * real_mode_data)
        /* Make NULL pointers segfault */
        zap_identity_mappings();
 
+       /* Cleanup the over mapped high alias */
+       cleanup_highmap();
+
        max_pfn_mapped = KERNEL_IMAGE_SIZE >> PAGE_SHIFT;
 
        for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 4e59873..64d152c 100644 (file)
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -297,9 +297,6 @@ static void __init init_gbpages(void)
 static inline void init_gbpages(void)
 {
 }
-static void __init cleanup_highmap(void)
-{
-}
 #endif
 
 static void __init reserve_brk(void)
@@ -925,8 +922,6 @@ void __init setup_arch(char **cmdline_p)
         */
        reserve_brk();
 
-       cleanup_highmap();
-
        memblock.current_limit = get_max_mapped();
        memblock_x86_fill();
 

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index f13ff3a..947f42a 100644 (file)
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -279,6 +279,25 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
        load_cr3(swapper_pg_dir);
 #endif
 
+#ifdef CONFIG_X86_64
+       if (!after_bootmem && !start) {
+               pud_t *pud;
+               pmd_t *pmd;
+
+               mmu_cr4_features = read_cr4();
+
+               /*
+                * _brk_end cannot change anymore, but it and _end may be
+                * located on different 2M pages. cleanup_highmap(), however,
+                * can only consider _end when it runs, so destroy any
+                * mappings beyond _brk_end here.
+                */
+               pud = pud_offset(pgd_offset_k(_brk_end), _brk_end);
+               pmd = pmd_offset(pud, _brk_end - 1);
+               while (++pmd <= pmd_offset(pud, (unsigned long)_end - 1))
+                       pmd_clear(pmd);
+       }
+#endif
        __flush_tlb_all();
 
        if (!after_bootmem && e820_table_end > e820_table_start)

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 68f9921..c14a542 100644 (file)
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -51,7 +51,6 @@
 #include <asm/numa.h>
 #include <asm/cacheflush.h>
 #include <asm/init.h>
-#include <asm/setup.h>
 
 static int __init parse_direct_gbpages_off(char *arg)
 {
@@ -294,18 +293,18 @@ void __init init_extra_mapping_uc(unsigned long phys, unsigned long size)
  * to the compile time generated pmds. This results in invalid pmds up
  * to the point where we hit the physaddr 0 mapping.
  *
- * We limit the mappings to the region from _text to _brk_end.  _brk_end
- * is rounded up to the 2MB boundary. This catches the invalid pmds as
+ * We limit the mappings to the region from _text to _end.  _end is
+ * rounded up to the 2MB boundary. This catches the invalid pmds as
  * well, as they are located before _text:
  */
 void __init cleanup_highmap(void)
 {
        unsigned long vaddr = __START_KERNEL_map;
-       unsigned long vaddr_end = __START_KERNEL_map + (max_pfn_mapped << PAGE_SHIFT);
-       unsigned long end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
+       unsigned long end = roundup((unsigned long)_end, PMD_SIZE) - 1;
        pmd_t *pmd = level2_kernel_pgt;
+       pmd_t *last_pmd = pmd + PTRS_PER_PMD;
 
-       for (; vaddr + PMD_SIZE - 1 < vaddr_end; pmd++, vaddr += PMD_SIZE) {
+       for (; pmd < last_pmd; pmd++, vaddr += PMD_SIZE) {
                if (pmd_none(*pmd))
                        continue;
                if (vaddr < (unsigned long) _text || vaddr > end)