x86: Cleanup highmap after brk is concluded

commit e5f15b45ddf3afa2bbbb10c7ea34fb32b6de0a0e upstream.

Now cleanup_highmap actually is in two steps: one is early in head64.c
and only clears above _end; a second one is in init_memory_mapping() and
tries to clean from _brk_end to _end.
It should check if those boundaries are PMD_SIZE aligned but currently
does not.
Also init_memory_mapping() is called several times for numa or memory
hotplug, so we really should not handle initial kernel mappings there.

This patch moves cleanup_highmap() down after _brk_end is settled so
we can do everything in one step.
Also we honor max_pfn_mapped in the implementation of cleanup_highmap.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
LKML-Reference: <alpine.DEB.2.00.1103171739050.3382@kaball-desktop>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index b5a9896ca1e74be8805c4f5384ffc8d50f6589b6..9ea4f8130ba89f3938b4849ec424c0945bb43d3b 100644 (file)
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -76,9 +76,6 @@ 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();
-
        for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {
 #ifdef CONFIG_EARLY_PRINTK
                set_intr_gate(i, &early_idt_handlers[i]);

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 92435869e170416c236138e08bff490eb04fff21..45fd3d06eec4d89f174d5c903ca38016c8e0335f 100644 (file)
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -295,6 +295,9 @@ 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)
@@ -895,6 +898,8 @@ void __init setup_arch(char **cmdline_p)
 
        reserve_brk();
 
+       cleanup_highmap();
+
        /*
         * Find and reserve possible boot-time SMP configuration:
         */

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index d406c5239019ee0e2e9609c826f1a2ba8564c693..e7e432f7684b2b50c047f5718ff5f9bfe8d0f511 100644 (file)
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -283,25 +283,6 @@ 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 69ddfbd911357534125bc5bb300776562a747ad8..19c9ed44eb11d6c6b909921e7b4c7444302f1fa7 100644 (file)
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -49,6 +49,7 @@
 #include <asm/numa.h>
 #include <asm/cacheflush.h>
 #include <asm/init.h>
+#include <asm/setup.h>
 #include <linux/bootmem.h>
 
 static unsigned long dma_reserve __initdata;
@@ -257,18 +258,18 @@ 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 _end.  _end is
- * rounded up to the 2MB boundary. This catches the invalid pmds as
+ * 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
  * well, as they are located before _text:
  */
 void __init cleanup_highmap(void)
 {
        unsigned long vaddr = __START_KERNEL_map;
-       unsigned long end = roundup((unsigned long)_end, PMD_SIZE) - 1;
+       unsigned long vaddr_end = __START_KERNEL_map + (max_pfn_mapped << PAGE_SHIFT);
+       unsigned long end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
        pmd_t *pmd = level2_kernel_pgt;
-       pmd_t *last_pmd = pmd + PTRS_PER_PMD;
 
-       for (; pmd < last_pmd; pmd++, vaddr += PMD_SIZE) {
+       for (; vaddr + PMD_SIZE - 1 < vaddr_end; pmd++, vaddr += PMD_SIZE) {
                if (pmd_none(*pmd))
                        continue;
                if (vaddr < (unsigned long) _text || vaddr > end)