3 files changed, 9 insertions, 2 deletions

diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index bd7acc71e8a9..c19b686db9b8 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -65,6 +65,7 @@ EXPORT_SYMBOL(pm_idle);
 void (*pm_power_off) (void);
 EXPORT_SYMBOL(pm_power_off);
 
+u32 acpi_rsdt_forced;
 unsigned int acpi_cpei_override;
 unsigned int acpi_cpei_phys_cpuid;
 
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index de8ce79dd881..39ae3d0e3a4a 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -47,7 +47,7 @@
 #endif
 
 static int __initdata acpi_force = 0;
-
+u32 acpi_rsdt_forced;
 #ifdef  CONFIG_ACPI
 int acpi_disabled = 0;
 #else
@@ -1794,6 +1794,10 @@ static int __init parse_acpi(char *arg)
                         disable_acpi();
                 acpi_ht = 1;
         }
+        /* acpi=rsdt use RSDT instead of XSDT */
+        else if (strcmp(arg, "rsdt") == 0) {
+                acpi_rsdt_forced = 1;
+        }
         /* "acpi=noirq" disables ACPI interrupt routing */
         else if (strcmp(arg, "noirq") == 0) {
                 acpi_noirq_set();
diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c
index c2502eb9aa83..a4805b3b4095 100644
--- a/arch/x86/kernel/acpi/cstate.c
+++ b/arch/x86/kernel/acpi/cstate.c
@@ -56,6 +56,7 @@ static struct cstate_entry *cpu_cstate_entry;	/* per CPU ptr */
 static short mwait_supported[ACPI_PROCESSOR_MAX_POWER];
 
 #define MWAIT_SUBSTATE_MASK     (0xf)
+#define MWAIT_CSTATE_MASK       (0xf)
 #define MWAIT_SUBSTATE_SIZE     (4)
 
 #define CPUID_MWAIT_LEAF (5)
@@ -98,7 +99,8 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu,
         cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
 
         /* Check whether this particular cx_type (in CST) is supported or not */
-        cstate_type = (cx->address >> MWAIT_SUBSTATE_SIZE) + 1;
+        cstate_type = ((cx->address >> MWAIT_SUBSTATE_SIZE) &
+                        MWAIT_CSTATE_MASK) + 1;
         edx_part = edx >> (cstate_type * MWAIT_SUBSTATE_SIZE);
         num_cstate_subtype = edx_part & MWAIT_SUBSTATE_MASK;