x86, microcode, amd: Make find_ucode_in_initrd() __init

Change find_ucode_in_initrd() to __init and only let BSP call it
during cold boot. This is the right thing to do because only BSP will
see initrd loaded by the boot loader. APs will offset into
initrd_start to find the microcode patch binary.
Reported-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Link: http://lkml.kernel.org/r/1370463236-2115-2-git-send-email-jacob.shin@amd.com
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/microcode_amd_early.c

@@ -9,6 +9,7 @@
  */
 
 #include <linux/earlycpio.h>
+#include <linux/initrd.h>
 
 #include <asm/cpu.h>
 #include <asm/setup.h>
@@ -16,40 +17,59 @@
 
 static bool ucode_loaded;
 static u32 ucode_new_rev;
+static unsigned long ucode_offset;
+static size_t ucode_size;
 
 /*
  * Microcode patch container file is prepended to the initrd in cpio format.
  * See Documentation/x86/early-microcode.txt
  */
-static __cpuinitdata char ucode_path[] = "kernel/x86/microcode/AuthenticAMD.bin";
+static __initdata char ucode_path[] = "kernel/x86/microcode/AuthenticAMD.bin";
 
-static struct cpio_data __cpuinit find_ucode_in_initrd(void)
+static struct cpio_data __init find_ucode_in_initrd(void)
 {
 	long offset = 0;
+	char *path;
+	void *start;
+	size_t size;
+	unsigned long *uoffset;
+	size_t *usize;
 	struct cpio_data cd;
 
 #ifdef CONFIG_X86_32
+	struct boot_params *p;
+
 	/*
 	 * On 32-bit, early load occurs before paging is turned on so we need
 	 * to use physical addresses.
 	 */
-	if (!(read_cr0() & X86_CR0_PG)) {
-		struct boot_params *p;
-		p  = (struct boot_params *)__pa_nodebug(&boot_params);
-		cd = find_cpio_data((char *)__pa_nodebug(ucode_path),
-			(void *)p->hdr.ramdisk_image, p->hdr.ramdisk_size,
-			&offset);
-	} else
+	p       = (struct boot_params *)__pa_nodebug(&boot_params);
+	path    = (char *)__pa_nodebug(ucode_path);
+	start   = (void *)p->hdr.ramdisk_image;
+	size    = p->hdr.ramdisk_size;
+	uoffset = (unsigned long *)__pa_nodebug(&ucode_offset);
+	usize   = (size_t *)__pa_nodebug(&ucode_size);
+#else
+	path    = ucode_path;
+	start   = (void *)(boot_params.hdr.ramdisk_image + PAGE_OFFSET);
+	size    = boot_params.hdr.ramdisk_size;
+	uoffset = &ucode_offset;
+	usize   = &ucode_size;
 #endif
-		cd = find_cpio_data(ucode_path,
-			(void *)(boot_params.hdr.ramdisk_image + PAGE_OFFSET),
-			boot_params.hdr.ramdisk_size, &offset);
+
+	cd = find_cpio_data(path, start, size, &offset);
+	if (!cd.data)
+		return cd;
 
 	if (*(u32 *)cd.data != UCODE_MAGIC) {
 		cd.data = NULL;
 		cd.size = 0;
+		return cd;
 	}
 
+	*uoffset = (u8 *)cd.data - (u8 *)start;
+	*usize   = cd.size;
+
 	return cd;
 }
 
@@ -62,9 +82,8 @@ static struct cpio_data __cpuinit find_ucode_in_initrd(void)
  * load_microcode_amd() to save equivalent cpu table and microcode patches in
  * kernel heap memory.
  */
-static void __cpuinit apply_ucode_in_initrd(void)
+static void __cpuinit apply_ucode_in_initrd(void *ucode, size_t size)
 {
-	struct cpio_data cd;
 	struct equiv_cpu_entry *eq;
 	u32 *header;
 	u8  *data;
@@ -78,12 +97,9 @@ static void __cpuinit apply_ucode_in_initrd(void)
 #else
 	new_rev = &ucode_new_rev;
 #endif
-	cd = find_ucode_in_initrd();
-	if (!cd.data)
-		return;
 
-	data   = cd.data;
-	left   = cd.size;
+	data   = ucode;
+	left   = size;
 	header = (u32 *)data;
 
 	/* find equiv cpu table */
@@ -129,7 +145,11 @@ static void __cpuinit apply_ucode_in_initrd(void)
 
 void __init load_ucode_amd_bsp(void)
 {
-	apply_ucode_in_initrd();
+	struct cpio_data cd = find_ucode_in_initrd();
+	if (!cd.data)
+		return;
+
+	apply_ucode_in_initrd(cd.data, cd.size);
 }
 
 #ifdef CONFIG_X86_32
@@ -145,12 +165,25 @@ u8 amd_bsp_mpb[MPB_MAX_SIZE];
 void __cpuinit load_ucode_amd_ap(void)
 {
 	struct microcode_amd *mc;
+	unsigned long *initrd;
+	unsigned long *uoffset;
+	size_t *usize;
+	void *ucode;
 
 	mc = (struct microcode_amd *)__pa_nodebug(amd_bsp_mpb);
-	if (mc->hdr.patch_id && mc->hdr.processor_rev_id)
+	if (mc->hdr.patch_id && mc->hdr.processor_rev_id) {
 		__apply_microcode_amd(mc);
-	else
-		apply_ucode_in_initrd();
+		return;
+	}
+
+	initrd  = (unsigned long *)__pa_nodebug(&initrd_start);
+	uoffset = (unsigned long *)__pa_nodebug(&ucode_offset);
+	usize   = (size_t *)__pa_nodebug(&ucode_size);
+	if (!*usize)
+		return;
+
+	ucode = (void *)((unsigned long)__pa_nodebug(*initrd) + *uoffset);
+	apply_ucode_in_initrd(ucode, *usize);
 }
 
 static void __init collect_cpu_sig_on_bsp(void *arg)
@@ -181,8 +214,13 @@ void __cpuinit load_ucode_amd_ap(void)
 	collect_cpu_info_amd_early(&cpu_data(cpu), ucode_cpu_info + cpu);
 
 	if (cpu && !ucode_loaded) {
-		struct cpio_data cd = find_ucode_in_initrd();
-		if (load_microcode_amd(0, cd.data, cd.size) != UCODE_OK)
+		void *ucode;
+
+		if (!ucode_size)
+			return;
+
+		ucode = (void *)(initrd_start + ucode_offset);
+		if (load_microcode_amd(0, ucode, ucode_size) != UCODE_OK)
 			return;
 		ucode_loaded = true;
 	}
@@ -194,7 +232,7 @@ void __cpuinit load_ucode_amd_ap(void)
 int __init save_microcode_in_initrd_amd(void)
 {
 	enum ucode_state ret;
-	struct cpio_data cd;
+	void *ucode;
 #ifdef CONFIG_X86_32
 	unsigned int bsp = boot_cpu_data.cpu_index;
 	struct ucode_cpu_info *uci = ucode_cpu_info + bsp;
@@ -209,11 +247,11 @@ int __init save_microcode_in_initrd_amd(void)
 	if (ucode_loaded)
 		return 0;
 
-	cd = find_ucode_in_initrd();
-	if (!cd.data)
-		return -EINVAL;
+	if (!ucode_size)
+		return 0;
 
-	ret = load_microcode_amd(0, cd.data, cd.size);
+	ucode = (void *)(initrd_start + ucode_offset);
+	ret = load_microcode_amd(0, ucode, ucode_size);
 	if (ret != UCODE_OK)
 		return -EINVAL;