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 2d2673c28aff2754af1e6e8848e9068ab1a6cca5..5655c2272adb86244f1927127a40c705c5a4d447 100644 (file)
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -77,9 +77,6 @@ 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();
-
        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 a0f52af256a037eaca0fce91e00caad47018d65d..1d9b98e60dfc0a76e3460a600c5040abea54db1a 100644 (file)
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -297,6 +297,9 @@ 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)
@@ -922,6 +925,8 @@ 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 c0e28a13de7df55c1ee1b173b61fd2d18c50e49c..0398a733c387952fc5ca2c79c0f789613dbb9fd3 100644 (file)
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -279,25 +279,6 @@ 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 c14a5422e15226e72b1b7bc9655a0982ea706555..68f9921ae9c162e13f59a48f093c9edd3a5c8457 100644 (file)
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -51,6 +51,7 @@
 #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)
 {
@@ -293,18 +294,18 @@ 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)