On Wed, 23 Mar 2011, Greg KH wrote:
> On Wed, Mar 23, 2011 at 12:58:44PM +0000, Stefano Stabellini wrote:
> > Greg,
> > I have few commits that I think should be backported to the long term
> > stable trees because they fix serious bugs:
> > 
> > 
> > 47e9037ac16637cd7f12b8790ea7ce6680e42168
> > PCI hotplug: acpiphp: set current_state to D0 in register_slot
> > 
> > 8c3c283e6bf463ab498d6e7823aff6c4762314b6
> > Input: xen-kbdfront - advertise either absolute or relative coordinates
> > 
> > 14988a4d350ce3b41ecad4f63c4f44c56f5ae34d
> > xen: set max_pfn_mapped to the last pfn mapped
> > 
> > e5f15b45ddf3afa2bbbb10c7ea34fb32b6de0a0e
> > x86: Cleanup highmap after brk is concluded
> 
> What specific releases do you want to see these in?

I would like these fixes to be backported to the longterm trees, in
particular 2.6.32.


> > Backporting the last commit is non-trivial so for your convenience I
> > prepared a branch based on 2.6.32.33 with just that commit:
> > 
> > git://xenbits.xen.org/people/sstabellini/linux-pvhvm.git 
> > for-stable-2.6.32.33
> 
> Can you just email the patch, a whole git tree for a single patch that I
> will then have to pull out and import into a quilt tree is more work on
> my side that I don't need :)
 
sure, no problem :)


commit f10f61ecb15fc8a9a63e0a72d9905fe3522f144c
Author: Yinghai Lu <[email protected]>
Date:   Fri Mar 18 13:04:40 2011 +0000

    x86: Cleanup highmap after brk is concluded
    
    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 <[email protected]>
    Signed-off-by: Stefano Stabellini <[email protected]>

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 0b06cd7..0b08160 100644
--- 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 5449a26..76358ee 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -294,6 +294,9 @@ 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)
@@ -921,6 +924,8 @@ void __init setup_arch(char **cmdline_p)
 
        reserve_brk();
 
+       cleanup_highmap();
+
        init_gbpages();
 
        /* max_pfn_mapped is updated here */
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 73ffd55..6bce215 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -287,25 +287,6 @@ 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 7d095ad..1584023 100644
--- 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)

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