bitkeeper revision 1.1159.69.18 (413baa1bXGfcJkRulx6s9wKLDL1Kkg)

Clean up pagetable bootstrap in Linux 2.6. Write-protecting the two
pagetables is now clearer, and we properly deallocate the old pagetables
when we are done with them.

diff --git a/linux-2.6.8.1-xen-sparse/arch/xen/i386/kernel/cpu/common.c b/linux-2.6.8.1-xen-sparse/arch/xen/i386/kernel/cpu/common.c
index 6620406951a42ce5ee438c8edb46b882b45e60fc..465759bcfe9f4be729329287c26d593d5a6ba271 100644 (file)
--- a/linux-2.6.8.1-xen-sparse/arch/xen/i386/kernel/cpu/common.c
+++ b/linux-2.6.8.1-xen-sparse/arch/xen/i386/kernel/cpu/common.c
@@ -504,7 +504,7 @@ void __init cpu_gdt_init(struct Xgt_desc_struct *gdt_descr)
             va < gdt_descr->address + gdt_descr->size;
             va += PAGE_SIZE, f++) {
                frames[f] = virt_to_machine(va) >> PAGE_SHIFT;
-               wrprotect_bootpt(swapper_pg_dir, (void *)va, 1);
+               protect_page(swapper_pg_dir, (void *)va, PROT_ON);
        }
        flush_page_update_queue();
        if (HYPERVISOR_set_gdt(frames, gdt_descr->size / 8))

diff --git a/linux-2.6.8.1-xen-sparse/arch/xen/i386/mm/init.c b/linux-2.6.8.1-xen-sparse/arch/xen/i386/mm/init.c
index 0b2706b055fea582baa0fd2bb4a0127802854d00..7886cd64c7c9394c73c21d63c638528b6a16835c 100644 (file)
--- a/linux-2.6.8.1-xen-sparse/arch/xen/i386/mm/init.c
+++ b/linux-2.6.8.1-xen-sparse/arch/xen/i386/mm/init.c
@@ -76,11 +76,9 @@ static pte_t * __init one_page_table_init(pmd_t *pmd)
        if (pmd_none(*pmd)) {
                pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
                set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
-               flush_page_update_queue();
                if (page_table != pte_offset_kernel(pmd, 0))
                        BUG();  
 
-               wrprotect_bootpt((pgd_t *)start_info.pt_base, page_table, 1);
                return page_table;
        }
        
@@ -125,8 +123,7 @@ static void __init page_table_range_init (unsigned long start, unsigned long end
        }
 }
 
-/* NOTE: caller must call flush_page_update_queue() */
-void __init wrprotect_bootpt(pgd_t *pgd, void *page, int set)
+void __init protect_page(pgd_t *pgd, void *page, int mode)
 {
        pmd_t *pmd;
        pte_t *pte;
@@ -138,31 +135,25 @@ void __init wrprotect_bootpt(pgd_t *pgd, void *page, int set)
        pte = pte_offset_kernel(pmd, addr);
        if (!pte_present(*pte))
                return;
-       queue_l1_entry_update(pte, set ? pte_val_ma(*pte) & ~_PAGE_RW :
-           pte_val_ma(*pte) | _PAGE_RW);
+       queue_l1_entry_update(pte, mode ? pte_val_ma(*pte) & ~_PAGE_RW :
+                                       pte_val_ma(*pte) | _PAGE_RW);
 }
 
-/* NOTE: caller must call flush_page_update_queue() */
-static void __init protect_bootpt_entries(pgd_t *spgd, pgd_t *dpgd, int set,
-    int pmdupdate, int pmdset)
+void __init protect_pagetable(pgd_t *dpgd, pgd_t *spgd, int mode)
 {
        pmd_t *pmd;
        pte_t *pte;
        int pgd_idx, pmd_idx;
 
+       protect_page(dpgd, spgd, mode);
+
        for (pgd_idx = 0; pgd_idx < PTRS_PER_PGD_NO_HV; spgd++, pgd_idx++) {
                pmd = pmd_offset(spgd, 0);
                if (pmd_none(*pmd))
                        continue;
-               if (pmdupdate)
-                       wrprotect_bootpt(dpgd, pmd, pmdset);
                for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) {
-                       if (cpu_has_pse) {
-                               /* XXX */
-                       } else {
-                               pte = pte_offset_kernel(pmd, 0);
-                               wrprotect_bootpt(dpgd, pte, set);
-                       }
+                       pte = pte_offset_kernel(pmd, 0);
+                       protect_page(dpgd, pte, mode);
                }
        }
 }
@@ -536,18 +527,6 @@ out:
 
 #endif
 
-/*
- * - write protect new L1 pages in old pgd
- * - write protect new pgd page in old pgd
- * - write protect new pgd page in new pgd
- * - write protect new L1 pages in new pgd
- * - write protect old L1 pages in new pgd and write protect old pgd in
- *   new pgd
- * - pin new pgd
- * - switch to new pgd
- * - unpin old pgd
- * - make old L1 pages and old pgd page writeable in new pgd
- */
 /*
  * paging_init() sets up the page tables - note that the first 8MB are
  * already mapped by head.S.
@@ -557,6 +536,8 @@ out:
  */
 void __init paging_init(void)
 {
+       pgd_t *old_pgd = (pgd_t *)start_info.pt_base;
+       pgd_t *new_pgd = swapper_pg_dir;
 #ifdef CONFIG_XEN_PHYSDEV_ACCESS
        int i;
 #endif
@@ -569,21 +550,25 @@ void __init paging_init(void)
 
        pagetable_init();
 
-       wrprotect_bootpt((pgd_t *)start_info.pt_base, swapper_pg_dir, 1);
-       wrprotect_bootpt(swapper_pg_dir, swapper_pg_dir, 1);
-       flush_page_update_queue();
-       protect_bootpt_entries(swapper_pg_dir, swapper_pg_dir, 1, 0, 0);
-       protect_bootpt_entries((pgd_t *)start_info.pt_base, swapper_pg_dir,
-           1, 1, 1);
-       queue_pgd_pin(__pa(swapper_pg_dir));
-       load_cr3(swapper_pg_dir);
+       /*
+        * Write-protect both page tables within both page tables.
+        * That's three ops, as the old p.t. is already protected
+        * within the old p.t. Then pin the new table, switch tables,
+        * and unprotect the old table.
+        */
+       protect_pagetable(new_pgd, old_pgd, PROT_ON);
+       protect_pagetable(new_pgd, new_pgd, PROT_ON);
+       protect_pagetable(old_pgd, new_pgd, PROT_ON);
+       queue_pgd_pin(__pa(new_pgd));
+       load_cr3(new_pgd);
+       queue_pgd_unpin(__pa(old_pgd));
        __flush_tlb_all(); /* implicit flush */
-       queue_pgd_unpin(__pa(start_info.pt_base));
-       protect_bootpt_entries((pgd_t *)start_info.pt_base, swapper_pg_dir,
-           0, 1, 0);
-       wrprotect_bootpt((pgd_t *)start_info.pt_base, swapper_pg_dir, 0);
+       protect_pagetable(new_pgd, old_pgd, PROT_OFF);
        flush_page_update_queue();
 
+       /* Completely detached from old tables, so free them. */
+       free_bootmem(__pa(old_pgd), start_info.nr_pt_frames << PAGE_SHIFT);
+
 #ifdef CONFIG_X86_PAE
        /*
         * We will bail out later - printk doesn't work right now so

diff --git a/linux-2.6.8.1-xen-sparse/include/asm-xen/hypervisor.h b/linux-2.6.8.1-xen-sparse/include/asm-xen/hypervisor.h
index 4d7ddc55a7f03863c30f0c44b5b7f6173e96edcb..e1ee44a014093a2e419136677add57a72e8d46f1 100644 (file)
--- a/linux-2.6.8.1-xen-sparse/include/asm-xen/hypervisor.h
+++ b/linux-2.6.8.1-xen-sparse/include/asm-xen/hypervisor.h
@@ -34,7 +34,11 @@ void xen_cpu_idle (void);
 void do_hypervisor_callback(struct pt_regs *regs);
 
 /* arch/xen/i386/mm/init.c */
-void wrprotect_bootpt(pgd_t *, void *, int);
+/* NOTE: caller must call flush_page_update_queue() */
+#define PROT_ON  1
+#define PROT_OFF 0
+void /* __init */ protect_page(pgd_t *dpgd, void *page, int mode);
+void /* __init */ protect_pagetable(pgd_t *dpgd, pgd_t *spgd, int mode);
 
 /* arch/xen/i386/kernel/head.S */
 void lgdt_finish(void);

diff --git a/xen/common/domain.c b/xen/common/domain.c
index 314f875511b075b51668ed8a51f3f6639f4242d9..f64d21e7117611124345ef0cedf83c2e1c38c083 100644 (file)
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -65,7 +65,7 @@ struct domain *do_createdomain(domid_t dom_id, unsigned int cpu)
         strncpy(d->name, buf, MAX_DOMAIN_NAME);
         d->name[MAX_DOMAIN_NAME-1] = '\0';
 
-       arch_do_createdomain(d);
+        arch_do_createdomain(d);
 
         sched_add_domain(d);
 
@@ -152,8 +152,8 @@ void domain_crash(void)
 {
     struct domain *d;
 
-    if (current->domain == 0)
-       BUG();
+    if ( current->domain == 0 )
+        BUG();
 
     set_bit(DF_CRASHED, &current->flags);