x86/microcode: Fix suspend to RAM with builtin microcode

commit 4b703305d98bf7350d4b2953ee39a3aa2eeb1778 upstream.

Usually, after we have found the proper microcode blob for the current
machine, we stash it away for later use with save_microcode_in_initrd().

However, with builtin microcode which doesn't come from the initrd, we
don't call that function because CONFIG_BLK_DEV_INITRD=n and even if
set, we don't have a valid initrd.

In order to fix this, let's make save_microcode_in_initrd() an
fs_initcall which runs before rootfs_initcall() as this was the time it
was called previously through:

 rootfs_initcall(populate_rootfs)
 |-> free_initrd()
     |-> free_initrd_mem()
         |-> save_microcode_in_initrd()

Also, we make it run independently from initrd functionality being
present or not.

And since it is called in the microcode loader only now, we can also
make it static.

Reported-and-tested-by: Jim Bos <jim876@xs4all.nl>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1465225850-7352-3-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 2 insertions, 10 deletions

diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index 9d3a96c4da78..01c2d14ec05f 100644
--- a/arch/x86/include/asm/microcode.h
+++ b/arch/x86/include/asm/microcode.h
@@ -133,13 +133,11 @@ static inline unsigned int x86_cpuid_family(void)
 #ifdef CONFIG_MICROCODE
 extern void __init load_ucode_bsp(void);
 extern void load_ucode_ap(void);
-extern int __init save_microcode_in_initrd(void);
 void reload_early_microcode(void);
 extern bool get_builtin_firmware(struct cpio_data *cd, const char *name);
 #else
 static inline void __init load_ucode_bsp(void)			{ }
 static inline void load_ucode_ap(void)				{ }
-static inline int __init save_microcode_in_initrd(void)		{ return 0; }
 static inline void reload_early_microcode(void)			{ }
 static inline bool
 get_builtin_firmware(struct cpio_data *cd, const char *name)	{ return false; }
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index ac360bfbbdb6..12823b6ebd6d 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -175,7 +175,7 @@ void load_ucode_ap(void)
 	}
 }
 
-int __init save_microcode_in_initrd(void)
+static int __init save_microcode_in_initrd(void)
 {
 	struct cpuinfo_x86 *c = &boot_cpu_data;
 
@@ -691,4 +691,5 @@ int __init microcode_init(void)
 	return error;
 
 }
+fs_initcall(save_microcode_in_initrd);
 late_initcall(microcode_init);
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 9d56f271d519..6df291c2987c 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -696,13 +696,6 @@ void free_initmem(void)
 void __init free_initrd_mem(unsigned long start, unsigned long end)
 {
 	/*
-	 * Remember, initrd memory may contain microcode or other useful things.
-	 * Before we lose initrd mem, we need to find a place to hold them
-	 * now that normal virtual memory is enabled.
-	 */
-	save_microcode_in_initrd();
-
-	/*
 	 * end could be not aligned, and We can not align that,
 	 * decompresser could be confused by aligned initrd_end
 	 * We already reserve the end partial page before in