This adds a patch for the vanilla kernel, to be pushed upstream some

day. It adds a #define which is 1 or 0 depending on whether the pmd
for the kernel address space is shared or not. Xen can't use a
shared pmd due to linear mappings in the Xen private area.

Also includes patches for modified files in the sparse tree.

Signed-off-by: Gerd Knorr <kraxel@suse.de>
Signed-off-by: Keir Fraser <keir@xensource.com>

diff --git a/linux-2.6-xen-sparse/arch/xen/i386/mm/pgtable.c b/linux-2.6-xen-sparse/arch/xen/i386/mm/pgtable.c
index 8043cc1c4dc1002ac75ac88f99dd4b9b2601435f..cd03f91a97bc5fcaaef302b1cf59de5386862e08 100644 (file)
--- a/linux-2.6-xen-sparse/arch/xen/i386/mm/pgtable.c
+++ b/linux-2.6-xen-sparse/arch/xen/i386/mm/pgtable.c
@@ -274,14 +274,14 @@ void pgd_ctor(void *pgd, kmem_cache_t *cache, unsigned long unused)
 {
        unsigned long flags;
 
-       if (PTRS_PER_PMD == 1)
+       if (!HAVE_SHARED_KERNEL_PMD)
                spin_lock_irqsave(&pgd_lock, flags);
 
        memcpy((pgd_t *)pgd + USER_PTRS_PER_PGD,
                        swapper_pg_dir + USER_PTRS_PER_PGD,
                        (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 
-       if (PTRS_PER_PMD > 1)
+       if (HAVE_SHARED_KERNEL_PMD)
                return;
 
        pgd_list_add(pgd);
@@ -289,12 +289,11 @@ void pgd_ctor(void *pgd, kmem_cache_t *cache, unsigned long unused)
        memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
 }
 
-/* never called when PTRS_PER_PMD > 1 */
 void pgd_dtor(void *pgd, kmem_cache_t *cache, unsigned long unused)
 {
        unsigned long flags; /* can be called from interrupt context */
 
-       if (PTRS_PER_PMD > 1)
+       if (HAVE_SHARED_KERNEL_PMD)
                return;
 
        spin_lock_irqsave(&pgd_lock, flags);
@@ -304,12 +303,30 @@ void pgd_dtor(void *pgd, kmem_cache_t *cache, unsigned long unused)
 
 pgd_t *pgd_alloc(struct mm_struct *mm)
 {
-       int i;
+       int i = 0;
        pgd_t *pgd = kmem_cache_alloc(pgd_cache, GFP_KERNEL);
 
        if (PTRS_PER_PMD == 1 || !pgd)
                return pgd;
 
+       if (!HAVE_SHARED_KERNEL_PMD) {
+               /* alloc and copy kernel pmd */
+               unsigned long flags;
+               pgd_t *copy_pgd = pgd_offset_k(PAGE_OFFSET);
+               pud_t *copy_pud = pud_offset(copy_pgd, PAGE_OFFSET);
+               pmd_t *copy_pmd = pmd_offset(copy_pud, PAGE_OFFSET);
+               pmd_t *pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
+               if (0 == pmd)
+                       goto out_oom;
+
+               spin_lock_irqsave(&pgd_lock, flags);
+               memcpy(pmd, copy_pmd, PAGE_SIZE);
+               spin_unlock_irqrestore(&pgd_lock, flags);
+               make_page_readonly(pmd);
+               set_pgd(&pgd[USER_PTRS_PER_PGD], __pgd(1 + __pa(pmd)));
+       }
+
+       /* alloc user pmds */
        for (i = 0; i < USER_PTRS_PER_PGD; ++i) {
                pmd_t *pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
                if (!pmd)
@@ -339,9 +356,17 @@ void pgd_free(pgd_t *pgd)
        }
 
        /* in the PAE case user pgd entries are overwritten before usage */
-       if (PTRS_PER_PMD > 1)
-               for (i = 0; i < USER_PTRS_PER_PGD; ++i)
-                       kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
+       if (PTRS_PER_PMD > 1) {
+               for (i = 0; i < USER_PTRS_PER_PGD; ++i) {
+                       pmd_t *pmd = (void *)__va(pgd_val(pgd[i])-1);
+                       kmem_cache_free(pmd_cache, pmd);
+               }
+               if (!HAVE_SHARED_KERNEL_PMD) {
+                       pmd_t *pmd = (void *)__va(pgd_val(pgd[USER_PTRS_PER_PGD])-1);
+                       make_page_writable(pmd);
+                       kmem_cache_free(pmd_cache, pmd);
+               }
+       }
        /* in the non-PAE case, free_pgtables() clears user pgd entries */
        kmem_cache_free(pgd_cache, pgd);
 }

diff --git a/linux-2.6-xen-sparse/include/asm-xen/asm-i386/pgtable-2level-defs.h b/linux-2.6-xen-sparse/include/asm-xen/asm-i386/pgtable-2level-defs.h
index 2be63665a4e7712461af8770286ee7f523d0599f..3791d2de3964f5529be3e0ba37379243b8dccba4 100644 (file)
--- a/linux-2.6-xen-sparse/include/asm-xen/asm-i386/pgtable-2level-defs.h
+++ b/linux-2.6-xen-sparse/include/asm-xen/asm-i386/pgtable-2level-defs.h
@@ -1,6 +1,8 @@
 #ifndef _I386_PGTABLE_2LEVEL_DEFS_H
 #define _I386_PGTABLE_2LEVEL_DEFS_H
 
+#define HAVE_SHARED_KERNEL_PMD 0
+
 /*
  * traditional i386 two-level paging structure:
  */

diff --git a/patches/linux-2.6.12/pmd-shared.patch b/patches/linux-2.6.12/pmd-shared.patch
new file mode 100644 (file)
index 0000000..af0dcd2
--- /dev/null
+++ b/patches/linux-2.6.12/pmd-shared.patch
@@ -0,0 +1,134 @@
+diff -urNpP linux-2.6.12/arch/i386/mm/init.c linux-2.6.12.new/arch/i386/mm/init.c
+--- linux-2.6.12/arch/i386/mm/init.c   2005-06-17 20:48:29.000000000 +0100
++++ linux-2.6.12.new/arch/i386/mm/init.c       2005-07-11 16:28:09.778165582 +0100
+@@ -634,7 +634,7 @@ void __init pgtable_cache_init(void)
+                               PTRS_PER_PGD*sizeof(pgd_t),
+                               0,
+                               pgd_ctor,
+-                              PTRS_PER_PMD == 1 ? pgd_dtor : NULL);
++                              pgd_dtor);
+       if (!pgd_cache)
+               panic("pgtable_cache_init(): Cannot create pgd cache");
+ }
+diff -urNpP linux-2.6.12/arch/i386/mm/pageattr.c linux-2.6.12.new/arch/i386/mm/pageattr.c
+--- linux-2.6.12/arch/i386/mm/pageattr.c       2005-06-17 20:48:29.000000000 +0100
++++ linux-2.6.12.new/arch/i386/mm/pageattr.c   2005-07-11 16:28:09.775165494 +0100
+@@ -75,7 +75,7 @@ static void set_pmd_pte(pte_t *kpte, uns
+       unsigned long flags;
+ 
+       set_pte_atomic(kpte, pte);      /* change init_mm */
+-      if (PTRS_PER_PMD > 1)
++      if (HAVE_SHARED_KERNEL_PMD)
+               return;
+ 
+       spin_lock_irqsave(&pgd_lock, flags);
+diff -urNpP linux-2.6.12/arch/i386/mm/pgtable.c linux-2.6.12.new/arch/i386/mm/pgtable.c
+--- linux-2.6.12/arch/i386/mm/pgtable.c        2005-06-17 20:48:29.000000000 +0100
++++ linux-2.6.12.new/arch/i386/mm/pgtable.c    2005-07-11 16:32:01.478023726 +0100
+@@ -199,14 +199,14 @@ void pgd_ctor(void *pgd, kmem_cache_t *c
+ {
+       unsigned long flags;
+ 
+-      if (PTRS_PER_PMD == 1)
++      if (!HAVE_SHARED_KERNEL_PMD)
+               spin_lock_irqsave(&pgd_lock, flags);
+ 
+       memcpy((pgd_t *)pgd + USER_PTRS_PER_PGD,
+                       swapper_pg_dir + USER_PTRS_PER_PGD,
+                       (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
+ 
+-      if (PTRS_PER_PMD > 1)
++      if (HAVE_SHARED_KERNEL_PMD)
+               return;
+ 
+       pgd_list_add(pgd);
+@@ -214,11 +214,13 @@ void pgd_ctor(void *pgd, kmem_cache_t *c
+       memset(pgd, 0, USER_PTRS_PER_PGD*sizeof(pgd_t));
+ }
+ 
+-/* never called when PTRS_PER_PMD > 1 */
+ void pgd_dtor(void *pgd, kmem_cache_t *cache, unsigned long unused)
+ {
+       unsigned long flags; /* can be called from interrupt context */
+ 
++      if (HAVE_SHARED_KERNEL_PMD)
++              return;
++
+       spin_lock_irqsave(&pgd_lock, flags);
+       pgd_list_del(pgd);
+       spin_unlock_irqrestore(&pgd_lock, flags);
+@@ -226,12 +228,29 @@ void pgd_dtor(void *pgd, kmem_cache_t *c
+ 
+ pgd_t *pgd_alloc(struct mm_struct *mm)
+ {
+-      int i;
++      int i = 0;
+       pgd_t *pgd = kmem_cache_alloc(pgd_cache, GFP_KERNEL);
+ 
+       if (PTRS_PER_PMD == 1 || !pgd)
+               return pgd;
+ 
++      if (!HAVE_SHARED_KERNEL_PMD) {
++              /* alloc and copy kernel pmd */
++              unsigned long flags;
++              pgd_t *copy_pgd = pgd_offset_k(PAGE_OFFSET);
++              pud_t *copy_pud = pud_offset(copy_pgd, PAGE_OFFSET);
++              pmd_t *copy_pmd = pmd_offset(copy_pud, PAGE_OFFSET);
++              pmd_t *pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
++              if (0 == pmd)
++                      goto out_oom;
++
++              spin_lock_irqsave(&pgd_lock, flags);
++              memcpy(pmd, copy_pmd, PAGE_SIZE);
++              spin_unlock_irqrestore(&pgd_lock, flags);
++              set_pgd(&pgd[USER_PTRS_PER_PGD], __pgd(1 + __pa(pmd)));
++      }
++
++      /* alloc user pmds */
+       for (i = 0; i < USER_PTRS_PER_PGD; ++i) {
+               pmd_t *pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
+               if (!pmd)
+@@ -252,9 +271,16 @@ void pgd_free(pgd_t *pgd)
+       int i;
+ 
+       /* in the PAE case user pgd entries are overwritten before usage */
+-      if (PTRS_PER_PMD > 1)
+-              for (i = 0; i < USER_PTRS_PER_PGD; ++i)
+-                      kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
++      if (PTRS_PER_PMD > 1) {
++              for (i = 0; i < USER_PTRS_PER_PGD; ++i) {
++                      pmd_t *pmd = (void *)__va(pgd_val(pgd[i])-1);
++                      kmem_cache_free(pmd_cache, pmd);
++              }
++              if (!HAVE_SHARED_KERNEL_PMD) {
++                      pmd_t *pmd = (void *)__va(pgd_val(pgd[USER_PTRS_PER_PGD])-1);
++                      kmem_cache_free(pmd_cache, pmd);
++              }
++      }
+       /* in the non-PAE case, free_pgtables() clears user pgd entries */
+       kmem_cache_free(pgd_cache, pgd);
+ }
+diff -urNpP linux-2.6.12/include/asm-i386/pgtable-2level-defs.h linux-2.6.12.new/include/asm-i386/pgtable-2level-defs.h
+--- linux-2.6.12/include/asm-i386/pgtable-2level-defs.h        2005-06-17 20:48:29.000000000 +0100
++++ linux-2.6.12.new/include/asm-i386/pgtable-2level-defs.h    2005-07-11 16:28:09.733164251 +0100
+@@ -1,6 +1,8 @@
+ #ifndef _I386_PGTABLE_2LEVEL_DEFS_H
+ #define _I386_PGTABLE_2LEVEL_DEFS_H
+ 
++#define HAVE_SHARED_KERNEL_PMD 0
++
+ /*
+  * traditional i386 two-level paging structure:
+  */
+diff -urNpP linux-2.6.12/include/asm-i386/pgtable-3level-defs.h linux-2.6.12.new/include/asm-i386/pgtable-3level-defs.h
+--- linux-2.6.12/include/asm-i386/pgtable-3level-defs.h        2005-06-17 20:48:29.000000000 +0100
++++ linux-2.6.12.new/include/asm-i386/pgtable-3level-defs.h    2005-07-11 16:28:09.755164902 +0100
+@@ -1,6 +1,8 @@
+ #ifndef _I386_PGTABLE_3LEVEL_DEFS_H
+ #define _I386_PGTABLE_3LEVEL_DEFS_H
+ 
++#define HAVE_SHARED_KERNEL_PMD 1
++
+ /*
+  * PGDIR_SHIFT determines what a top-level page table entry can map
+  */