Simplify pagetable initialisation. Since swapper_pg_dir now

is the one allocated by the domain builder, we can be sure
it is below 4GB (essential for PAE).

Signed-off-by: Keir Fraser <keir@xensource.com>

linux-2.6-xen-sparse/arch/xen/i386/kernel/Makefile

@@ -14,8 +14,7 @@ obj-y	:= process.o signal.o entry.o traps.o \
 
 c-obj-y	:= semaphore.o vm86.o \
 		ptrace.o sys_i386.o \
-		i387.o dmi_scan.o bootflag.o \
-		doublefault.o
+		i387.o dmi_scan.o bootflag.o
 s-obj-y	:=
 
 obj-y				+= cpu/
@@ -85,7 +84,7 @@ $(obj)/vsyscall-syms.o: $(src)/vsyscall.lds \
 			$(obj)/vsyscall-sysenter.o FORCE
 	$(call if_changed,syscall)
 
-c-link	:= init_task.o
+c-link	:=
 s-link	:= vsyscall-int80.o vsyscall-sysenter.o vsyscall-sigreturn.o vsyscall.lds.o syscall_table.o
 
 $(patsubst %.o,$(obj)/%.c,$(c-obj-y) $(c-obj-m) $(c-link)) $(patsubst %.o,$(obj)/%.S,$(s-obj-y) $(s-link)):

linux-2.6-xen-sparse/arch/xen/i386/kernel/head.S

@@ -136,9 +136,6 @@ cpu_gdt_descr:
 ENTRY(empty_zero_page)
 
 .org 0x2000
-ENTRY(swapper_pg_dir)
-
-.org 0x3000
 ENTRY(cpu_gdt_table)
 	.quad 0x0000000000000000	/* NULL descriptor */
 	.quad 0x0000000000000000	/* 0x0b reserved */
@@ -190,10 +187,10 @@ ENTRY(cpu_gdt_table)
 	.quad 0x0000000000000000	/* 0xf8 - GDT entry 31: double-fault TSS */
 	.fill GDT_ENTRIES-32,8,0
 
-.org 0x4000
+.org 0x3000
 ENTRY(default_ldt)
 
-.org 0x5000
+.org 0x4000
 /*
  * Real beginning of normal "text" segment
  */

linux-2.6-xen-sparse/arch/xen/i386/kernel/init_task.c

@@ -0,0 +1,49 @@
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/init_task.h>
+#include <linux/fs.h>
+#include <linux/mqueue.h>
+
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/desc.h>
+
+static struct fs_struct init_fs = INIT_FS;
+static struct files_struct init_files = INIT_FILES;
+static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
+static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
+
+#define swapper_pg_dir ((pgd_t *)NULL)
+struct mm_struct init_mm = INIT_MM(init_mm);
+#undef swapper_pg_dir
+
+EXPORT_SYMBOL(init_mm);
+
+/*
+ * Initial thread structure.
+ *
+ * We need to make sure that this is THREAD_SIZE aligned due to the
+ * way process stacks are handled. This is done by having a special
+ * "init_task" linker map entry..
+ */
+union thread_union init_thread_union 
+	__attribute__((__section__(".data.init_task"))) =
+		{ INIT_THREAD_INFO(init_task) };
+
+/*
+ * Initial task structure.
+ *
+ * All other task structs will be allocated on slabs in fork.c
+ */
+struct task_struct init_task = INIT_TASK(init_task);
+
+EXPORT_SYMBOL(init_task);
+
+/*
+ * per-CPU TSS segments. Threads are completely 'soft' on Linux,
+ * no more per-task TSS's.
+ */ 
+DEFINE_PER_CPU(struct tss_struct, init_tss) ____cacheline_maxaligned_in_smp = INIT_TSS;
+

linux-2.6-xen-sparse/arch/xen/i386/mm/init.c

@@ -342,11 +342,15 @@ unsigned long long __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC;
 extern void __init remap_numa_kva(void);
 #endif
 
+pgd_t *swapper_pg_dir;
+
 static void __init pagetable_init (void)
 {
 	unsigned long vaddr;
-	pgd_t *pgd_base = swapper_pg_dir;
-	pgd_t *old_pgd = (pgd_t *)xen_start_info.pt_base;
+	pgd_t *pgd_base = (pgd_t *)xen_start_info.pt_base;
+
+	swapper_pg_dir = pgd_base;
+	init_mm.pgd    = pgd_base;
 
 #ifdef CONFIG_X86_PAE
 	int i;
@@ -367,44 +371,6 @@ static void __init pagetable_init (void)
 		__PAGE_KERNEL_EXEC |= _PAGE_GLOBAL;
 	}
 
-	/*
-	 * Switch to proper mm_init page directory. Initialise from the current
-	 * page directory, write-protect the new page directory, then switch to
-	 * it. We clean up by write-enabling and then freeing the old page dir.
-	 */
-#ifndef CONFIG_X86_PAE
-	memcpy(pgd_base, old_pgd, PTRS_PER_PGD_NO_HV*sizeof(pgd_t));
-	make_page_readonly(pgd_base);
-	xen_pgd_pin(__pa(pgd_base));
-	load_cr3(pgd_base);
-	xen_pgd_unpin(__pa(old_pgd));
-	make_page_writable(old_pgd);
-	__flush_tlb_all();
-	free_bootmem(__pa(old_pgd), PAGE_SIZE);
-#else
-	{
-		pud_t *old_pud = pud_offset(old_pgd+3, PAGE_OFFSET);
-		pmd_t *old_pmd = pmd_offset(old_pud, PAGE_OFFSET);
-		pmd_t *new_pmd = alloc_bootmem_low_pages(PAGE_SIZE);
-
-		memcpy(new_pmd,  old_pmd, PAGE_SIZE);
-		memcpy(pgd_base, old_pgd, PTRS_PER_PGD_NO_HV*sizeof(pgd_t));
-		set_pgd(&pgd_base[3], __pgd(__pa(new_pmd) | _PAGE_PRESENT));
-
-		make_page_readonly(new_pmd);
-		make_page_readonly(pgd_base);
-		xen_pgd_pin(__pa(pgd_base));
-		load_cr3(pgd_base);
-		xen_pgd_unpin(__pa(old_pgd));
-		make_page_writable(old_pgd);
-		make_page_writable(old_pmd);
-		__flush_tlb_all();
-
-		free_bootmem(__pa(old_pgd), PAGE_SIZE);
-		free_bootmem(__pa(old_pmd), PAGE_SIZE);
-	}
-#endif
-
 	init_mm.context.pinned = 1;
 	kernel_physical_mapping_init(pgd_base);
 	remap_numa_kva();

linux-2.6-xen-sparse/include/asm-xen/asm-i386/pgtable.h

@@ -32,7 +32,7 @@
  */
 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 extern unsigned long empty_zero_page[1024];
-extern pgd_t swapper_pg_dir[1024];
+extern pgd_t *swapper_pg_dir;
 extern kmem_cache_t *pgd_cache;
 extern kmem_cache_t *pmd_cache;
 extern spinlock_t pgd_lock;