[PATCH] x86: Save and restore the fixed-range MTRRs of the BSP when suspending

Note: This patch didn'nt need an update since it's initial post.

Some BIOSes may modify fixed-range MTRRs in SMM, e.g. when they
transition the system into ACPI mode, which is entered thru an SMI,
triggered by Linux in acpi_enable().

SMIs which cause that Linux is interrupted and BIOS code is
executed (which may change e.g. fixed-range MTRRs) in SMM may
be raised by an embedded system controller which is often found
in notebooks also at other occasions.

If we would not update our copy of the fixed-range MTRRs before
suspending to RAM or to disk, restore_processor_state() would
set the fixed-range MTRRs of the BSP using old backup values
which may be outdated and this could cause the system to fail
later during resume.

This patch ensures that our copy of the fixed-range MTRRs
is updated when saving the boot processor state on suspend
to disk and suspend to RAM.

In combination with other patches this allows to fix s2ram
and s2disk on the Acer Ferrari 1000 notebook and at least
s2disk on the Acer Ferrari 5000 notebook.

Signed-off-by: Bernhard Kaindl <bk@suse.de>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Dave Jones <davej@codemonkey.org.uk>

diff --git a/arch/i386/power/cpu.c b/arch/i386/power/cpu.c
index 2c15500f8713e001bd8c71fbc59136525a408fb9..998fd3ec0d68a5d252b9dc4f1e1a41dee4777a89 100644 (file)
--- a/arch/i386/power/cpu.c
+++ b/arch/i386/power/cpu.c
@@ -21,6 +21,7 @@ unsigned long saved_context_eflags;
 
 void __save_processor_state(struct saved_context *ctxt)
 {
+       mtrr_save_fixed_ranges(NULL);
        kernel_fpu_begin();
 
        /*

diff --git a/arch/x86_64/kernel/suspend.c b/arch/x86_64/kernel/suspend.c
index 4ca523d58a5b8f3e52cebfa07452a110ee08fbf9..6a5a98f2a75c5aac97d543f116db736182b6e73c 100644 (file)
--- a/arch/x86_64/kernel/suspend.c
+++ b/arch/x86_64/kernel/suspend.c
@@ -12,6 +12,7 @@
 #include <asm/proto.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
+#include <asm/mtrr.h>
 
 /* References to section boundaries */
 extern const void __nosave_begin, __nosave_end;
@@ -48,6 +49,7 @@ void __save_processor_state(struct saved_context *ctxt)
        rdmsrl(MSR_FS_BASE, ctxt->fs_base);
        rdmsrl(MSR_GS_BASE, ctxt->gs_base);
        rdmsrl(MSR_KERNEL_GS_BASE, ctxt->gs_kernel_base);
+       mtrr_save_fixed_ranges(NULL);
 
        /*
         * control registers