x86 ACPI: fix breakage of resume on 64-bit UP systems with SMP kernel

x86 ACPI: Fix breakage of resume on 64-bit UP systems with SMP kernel

We are now using per CPU GDT tables in head_64.S and the original
early_gdt_descr.address is invalidated after boot by
setup_per_cpu_areas().  This breaks resume from suspend to RAM on
x86_64 UP systems using SMP kernels, because this part of head_64.S
is also executed during the resume and the invalid GDT address
causes the system to crash.  It doesn't break on 'true' SMP systems,
because early_gdt_descr.address is modified every time
native_cpu_up() runs.  However, during resume it should point to the
GDT of the boot CPU rather than to another CPU's GDT.

For this reason, during suspend to RAM always make
early_gdt_descr.address point to the boot CPU's GDT.

This fixes http://bugzilla.kernel.org/show_bug.cgi?id=11568, which
is a regression from 2.6.26.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reported-and-tested-by: Andy Wettstein <ajw1980@gmail.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index 426e5d91b63..c44cd6dbfa1 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -10,6 +10,7 @@
 #include <linux/dmi.h>
 #include <linux/cpumask.h>
 #include <asm/segment.h>
+#include <asm/desc.h>
 
 #include "realmode/wakeup.h"
 #include "sleep.h"
@@ -98,6 +99,8 @@ int acpi_save_state_mem(void)
         header->trampoline_segment = setup_trampoline() >> 4;
 #ifdef CONFIG_SMP
         stack_start.sp = temp_stack + 4096;
+        early_gdt_descr.address =
+                        (unsigned long)get_cpu_gdt_table(smp_processor_id());
 #endif
         initial_code = (unsigned long)wakeup_long64;
         saved_magic = 0x123456789abcdef0;