Two fixes for early microcode loader on 32-bit:

* access the dis_ucode_ldr chicken bit properly
 * fix patch stashing on AMD on 32-bit
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Merge tag 'microcode_fixes_for_3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp into x86/urgent

Pull two fixes for early microcode loader on 32-bit from Borislav Petkov:

 - access the dis_ucode_ldr chicken bit properly
 - fix patch stashing on AMD on 32-bit

Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/cpu/microcode/amd_early.c

@@ -108,12 +108,13 @@ static size_t compute_container_size(u8 *data, u32 total_size)
  * load_microcode_amd() to save equivalent cpu table and microcode patches in
  * kernel heap memory.
  */
-static void apply_ucode_in_initrd(void *ucode, size_t size)
+static void apply_ucode_in_initrd(void *ucode, size_t size, bool save_patch)
 {
 	struct equiv_cpu_entry *eq;
 	size_t *cont_sz;
 	u32 *header;
 	u8  *data, **cont;
+	u8 (*patch)[PATCH_MAX_SIZE];
 	u16 eq_id = 0;
 	int offset, left;
 	u32 rev, eax, ebx, ecx, edx;
@@ -123,10 +124,12 @@ static void apply_ucode_in_initrd(void *ucode, size_t size)
 	new_rev = (u32 *)__pa_nodebug(&ucode_new_rev);
 	cont_sz = (size_t *)__pa_nodebug(&container_size);
 	cont	= (u8 **)__pa_nodebug(&container);
+	patch	= (u8 (*)[PATCH_MAX_SIZE])__pa_nodebug(&amd_ucode_patch);
 #else
 	new_rev = &ucode_new_rev;
 	cont_sz = &container_size;
 	cont	= &container;
+	patch	= &amd_ucode_patch;
 #endif
 
 	data   = ucode;
@@ -213,9 +216,9 @@ static void apply_ucode_in_initrd(void *ucode, size_t size)
 				rev = mc->hdr.patch_id;
 				*new_rev = rev;
 
-				/* save ucode patch */
-				memcpy(amd_ucode_patch, mc,
-				       min_t(u32, header[1], PATCH_MAX_SIZE));
+				if (save_patch)
+					memcpy(patch, mc,
+					       min_t(u32, header[1], PATCH_MAX_SIZE));
 			}
 		}
 
@@ -246,7 +249,7 @@ void __init load_ucode_amd_bsp(void)
 	*data = cp.data;
 	*size = cp.size;
 
-	apply_ucode_in_initrd(cp.data, cp.size);
+	apply_ucode_in_initrd(cp.data, cp.size, true);
 }
 
 #ifdef CONFIG_X86_32
@@ -263,7 +266,7 @@ void load_ucode_amd_ap(void)
 	size_t *usize;
 	void **ucode;
 
-	mc = (struct microcode_amd *)__pa(amd_ucode_patch);
+	mc = (struct microcode_amd *)__pa_nodebug(amd_ucode_patch);
 	if (mc->hdr.patch_id && mc->hdr.processor_rev_id) {
 		__apply_microcode_amd(mc);
 		return;
@@ -275,7 +278,7 @@ void load_ucode_amd_ap(void)
 	if (!*ucode || !*usize)
 		return;
 
-	apply_ucode_in_initrd(*ucode, *usize);
+	apply_ucode_in_initrd(*ucode, *usize, false);
 }
 
 static void __init collect_cpu_sig_on_bsp(void *arg)
@@ -339,7 +342,7 @@ void load_ucode_amd_ap(void)
 		 * AP has a different equivalence ID than BSP, looks like
 		 * mixed-steppings silicon so go through the ucode blob anew.
 		 */
-		apply_ucode_in_initrd(ucode_cpio.data, ucode_cpio.size);
+		apply_ucode_in_initrd(ucode_cpio.data, ucode_cpio.size, false);
 	}
 }
 #endif
@@ -347,6 +350,7 @@ void load_ucode_amd_ap(void)
 int __init save_microcode_in_initrd_amd(void)
 {
 	unsigned long cont;
+	int retval = 0;
 	enum ucode_state ret;
 	u8 *cont_va;
 	u32 eax;
@@ -387,7 +391,7 @@ int __init save_microcode_in_initrd_amd(void)
 
 	ret = load_microcode_amd(eax, container, container_size);
 	if (ret != UCODE_OK)
-		return -EINVAL;
+		retval = -EINVAL;
 
 	/*
 	 * This will be freed any msec now, stash patches for the current
@@ -396,5 +400,5 @@ int __init save_microcode_in_initrd_amd(void)
 	container = NULL;
 	container_size = 0;
 
-	return 0;
+	return retval;
 }

arch/x86/kernel/cpu/microcode/core_early.c

@@ -124,7 +124,7 @@ void __init load_ucode_bsp(void)
 static bool check_loader_disabled_ap(void)
 {
 #ifdef CONFIG_X86_32
-	return __pa_nodebug(dis_ucode_ldr);
+	return *((bool *)__pa_nodebug(&dis_ucode_ldr));
 #else
 	return dis_ucode_ldr;
 #endif