x86: Test mtrr support flag before accessing mtrr msr
On some x86 processors (like Intel Quark) the MTRR registers are not
supported. This is reflected by the CPUID (EAX 01H) result EDX[12].
Accessing the MTRR registers on such processors will cause #GP so we
must test the support flag before accessing MTRR MSRs.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/include/asm/mtrr.h b/arch/x86/include/asm/mtrr.h
index 3c11740..fda4eae 100644
--- a/arch/x86/include/asm/mtrr.h
+++ b/arch/x86/include/asm/mtrr.h
@@ -65,7 +65,6 @@
*
* @state: Structure from mtrr_open()
*/
-/* */
void mtrr_close(struct mtrr_state *state);
/**
@@ -76,6 +75,8 @@
* @type: Requested type (MTRR_TYPE_)
* @start: Start address
* @size: Size
+ *
+ * @return: 0 on success, non-zero on failure
*/
int mtrr_add_request(int type, uint64_t start, uint64_t size);
@@ -86,6 +87,8 @@
* It must be called with caches disabled.
*
* @do_caches: true if caches are currently on
+ *
+ * @return: 0 on success, non-zero on failure
*/
int mtrr_commit(bool do_caches);