[Xen-changelog] [xen-unstable] linux: Some save/restore simplifications and cleanups.

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir@xxxxxxxxxxxxx>
# Date 1172876496 0
# Node ID 29d4bca7a5037be8daa19e195b38191b02590c49
# Parent  d5ca4c37b3c53688cd556af6730017b902da5bc2
linux: Some save/restore simplifications and cleanups.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
 linux-2.6-xen-sparse/drivers/xen/core/machine_reboot.c |   38 ++++++++---------
 linux-2.6-xen-sparse/include/xen/cpu_hotplug.h         |    2 
 2 files changed, 20 insertions(+), 20 deletions(-)

diff -r d5ca4c37b3c5 -r 29d4bca7a503 
linux-2.6-xen-sparse/drivers/xen/core/machine_reboot.c
--- a/linux-2.6-xen-sparse/drivers/xen/core/machine_reboot.c    Fri Mar 02 
22:57:27 2007 +0000
+++ b/linux-2.6-xen-sparse/drivers/xen/core/machine_reboot.c    Fri Mar 02 
23:01:36 2007 +0000
@@ -59,23 +59,6 @@ EXPORT_SYMBOL(machine_halt);
 EXPORT_SYMBOL(machine_halt);
 EXPORT_SYMBOL(machine_power_off);
 
-/* Ensure we run on the idle task page tables so that we will
-   switch page tables before running user space. This is needed
-   on architectures with separate kernel and user page tables
-   because the user page table pointer is not saved/restored. */
-static void switch_idle_mm(void)
-{
-       struct mm_struct *mm = current->active_mm;
-
-       if (mm == &init_mm)
-               return;
-
-       atomic_inc(&init_mm.mm_count);
-       switch_mm(mm, &init_mm, current);
-       current->active_mm = &init_mm;
-       mmdrop(mm);
-}
-
 static void pre_suspend(void)
 {
        HYPERVISOR_shared_info = (shared_info_t *)empty_zero_page;
@@ -99,7 +82,9 @@ static void post_suspend(int suspend_can
                xen_start_info->console.domU.mfn =
                        pfn_to_mfn(xen_start_info->console.domU.mfn);
        } else {
+#ifdef CONFIG_SMP
                cpu_initialized_map = cpumask_of_cpu(0);
+#endif
        }
        
        set_fixmap(FIX_SHARED_INFO, xen_start_info->shared_info);
@@ -172,10 +157,25 @@ static int take_machine_down(void *p_fas
 
        post_suspend(suspend_cancelled);
        gnttab_resume();
-       if (!suspend_cancelled)
+       if (!suspend_cancelled) {
                irq_resume();
+#ifdef __x86_64__
+               /*
+                * Older versions of Xen do not save/restore the user %cr3.
+                * We do it here just in case, but there's no need if we are
+                * in fast-suspend mode as that implies a new enough Xen.
+                */
+               if (!fast_suspend) {
+                       struct mmuext_op op;
+                       op.cmd = MMUEXT_NEW_USER_BASEPTR;
+                       op.arg1.mfn = pfn_to_mfn(__pa(__user_pgd(
+                               current->active_mm->pgd)) >> PAGE_SHIFT);
+                       if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
+                               BUG();
+               }
+#endif
+       }
        time_resume();
-       switch_idle_mm();
        local_irq_enable();
 
        if (fast_suspend && !suspend_cancelled) {
diff -r d5ca4c37b3c5 -r 29d4bca7a503 
linux-2.6-xen-sparse/include/xen/cpu_hotplug.h
--- a/linux-2.6-xen-sparse/include/xen/cpu_hotplug.h    Fri Mar 02 22:57:27 
2007 +0000
+++ b/linux-2.6-xen-sparse/include/xen/cpu_hotplug.h    Fri Mar 02 23:01:36 
2007 +0000
@@ -4,7 +4,7 @@
 #include <linux/kernel.h>
 #include <linux/cpumask.h>
 
-#if defined(CONFIG_X86)
+#if defined(CONFIG_X86) && defined(CONFIG_SMP)
 extern cpumask_t cpu_initialized_map;
 #define cpu_set_initialized(cpu) cpu_set(cpu, cpu_initialized_map)
 #else

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