Re: [PATCH] restore sysenter MSRs at resume

[Nigel Cunningham]

Ok. I haven't updated it for 2.5.69 version, but it doesn't look like
any changes are required. Here is the relevant part of the full swsusp
patch.

Regards,

Nigel

On Mon, 2003-05-12 at 07:08, Pavel Machek wrote:
> Hi!
> 
> Nigel, perhaps this is the right time for retransmitting the mtrr
> patch?
> 
> 					Pavel
> > 
> > On Sat, 10 May 2003 [e-mail] wrote:
> > > 
> > > This patch should be better. It changes apm.c to invoke
> > > suspend.c's save and restore processor state procedures
> > > around suspends, which fixes the SYSENTER MSR problem.
> > 
> > Applied.
> > 
> > However, the fact that the SYSENTER MSR needs to be restored makes me
> > suspect that the other MSR/MTRR also will need restoring. I don't see 
> > where we'd be doing that, but it sounds to me like it should be done here 
> > too..
> > 
> > 		Linus

diff -ruN linux-2.5.68/arch/i386/kernel/cpu/mtrr/main.c linux-2.5.68-swsusp1925/arch/i386/kernel/cpu/mtrr/main.c
--- linux-2.5.68/arch/i386/kernel/cpu/mtrr/main.c	2003-01-15 17:00:38.000000000 +1300
+++ linux-2.5.68-swsusp1925/arch/i386/kernel/cpu/mtrr/main.c	2003-04-25 14:13:05.000000000 +1200
@@ -35,6 +35,7 @@
 #include <linux/init.h>
 #include <linux/pci.h>
 #include <linux/smp.h>
+#include <linux/suspend.h>
 
 #include <asm/mtrr.h>
 
@@ -644,6 +645,65 @@
     "write-protect",            /* 5 */
     "write-back",               /* 6 */
 };
-
+ 
+#ifdef SOFTWARE_SUSPEND_MTRR
+struct mtrr_suspend_state
+{
+     mtrr_type ltype;
+     unsigned long lbase;
+     unsigned int lsize;
+};
+/* We return a pointer ptr on an area of *ptr bytes
+   beginning at ptr+sizeof(int)
+   This buffer has to be saved in some way during suspension */
+int *mtrr_suspend(void)
+{
+     int i, len;
+     int *ptr = NULL;
+     static struct mtrr_suspend_state *mtrr_suspend_buffer=NULL;
+     
+     if(!mtrr_suspend_buffer)
+     {
+	  len = num_var_ranges * sizeof (struct mtrr_suspend_state) + sizeof(int);
+	  ptr = kmalloc (len, GFP_KERNEL);
+	  if (ptr == NULL)
+	       return(NULL);
+	  *ptr = len;
+	  ptr++;
+	  mtrr_suspend_buffer = (struct mtrr_suspend_state *)ptr;
+	  ptr--;
+     }
+     for (i = 0; i < num_var_ranges; ++i,mtrr_suspend_buffer++)
+	  mtrr_if->get (i,
+		       &(mtrr_suspend_buffer->lbase),
+		       &(mtrr_suspend_buffer->lsize),
+		       &(mtrr_suspend_buffer->ltype));
+     return(ptr);
+}
+
+/* We restore mtrrs from buffer ptr */
+void mtrr_resume(int *ptr)
+{
+     int i, len;
+     struct mtrr_suspend_state *mtrr_suspend_buffer;
+     
+     len = num_var_ranges * sizeof (struct mtrr_suspend_state) + sizeof(int);
+     if(*ptr != len)
+     {
+	  printk ("mtrr: Resuming failed due to different number of MTRRs\n");
+	  return;
+     }
+     ptr++;
+     mtrr_suspend_buffer=(struct mtrr_suspend_state *)ptr;
+     for (i = 0; i < num_var_ranges; ++i,mtrr_suspend_buffer++)     
+	  if (mtrr_suspend_buffer->lsize)	  
+	       set_mtrr(i,
+			mtrr_suspend_buffer->lbase,
+			mtrr_suspend_buffer->lsize,
+			mtrr_suspend_buffer->ltype);
+}
+EXPORT_SYMBOL(mtrr_suspend);
+EXPORT_SYMBOL(mtrr_resume);
+#endif
 core_initcall(mtrr_init);