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Subject[59/74] [PATCH] Revert "x86: Cleanup highmap after brk is concluded"
2.6.32-longterm review patch.  If anyone has any objections, please let us know.

------------------
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>

---
arch/x86/kernel/head64.c | 3 +++
arch/x86/kernel/setup.c | 5 -----
arch/x86/mm/init.c | 19 +++++++++++++++++++
arch/x86/mm/init_64.c | 11 +++++------
4 files changed, 27 insertions(+), 11 deletions(-)
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -76,6 +76,9 @@ void __init x86_64_start_kernel(char * r
/* 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]);
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -294,9 +294,6 @@ 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)
@@ -924,8 +921,6 @@ void __init setup_arch(char **cmdline_p)

reserve_brk();

- cleanup_highmap();
-
init_gbpages();

/* max_pfn_mapped is updated here */
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -287,6 +287,25 @@ unsigned long __init_refok init_memory_m
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)
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -49,7 +49,6 @@
#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;
@@ -258,18 +257,18 @@ void __init init_extra_mapping_uc(unsign
* 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)



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