x86, xsave: Check cpuid level for XSTATE_CPUID (0x0d)

The patch introduces the XSTATE_CPUID macro and adds a check that
tests if XSTATE_CPUID exists.

Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1279731838-1522-4-git-send-email-robert.richter@amd.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index 2322f586c051..5adb7fb408f0 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -379,7 +379,7 @@ static void setup_xstate_features(void)
         xstate_sizes = alloc_bootmem(xstate_features * sizeof(int));
 
         do {
-                cpuid_count(0xd, leaf, &eax, &ebx, &ecx, &edx);
+                cpuid_count(XSTATE_CPUID, leaf, &eax, &ebx, &ecx, &edx);
 
                 if (eax == 0)
                         break;
@@ -425,7 +425,12 @@ static void __cpuinit xstate_enable_boot_cpu(void)
 {
         unsigned int eax, ebx, ecx, edx;
 
-        cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
+        if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
+                WARN(1, KERN_ERR "XSTATE_CPUID missing\n");
+                return;
+        }
+
+        cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
         pcntxt_mask = eax + ((u64)edx << 32);
 
         if ((pcntxt_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
@@ -444,7 +449,7 @@ static void __cpuinit xstate_enable_boot_cpu(void)
         /*
          * Recompute the context size for enabled features
          */
-        cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
+        cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
         xstate_size = ebx;
 
         update_regset_xstate_info(xstate_size, pcntxt_mask);