[tip:x86/microcode] x86/microcode: Fix suspend to RAM with builtin microcode

[tip-bot for Borislav Petkov]

Commit-ID:  4b703305d98bf7350d4b2953ee39a3aa2eeb1778
Gitweb:     http://git.kernel.org/tip/4b703305d98bf7350d4b2953ee39a3aa2eeb1778
Author:     Borislav Petkov <bp@xxxxxxx>
AuthorDate: Mon, 6 Jun 2016 17:10:43 +0200
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 8 Jun 2016 11:04:19 +0200

x86/microcode: Fix suspend to RAM with builtin microcode

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@xxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v4.6
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1465225850-7352-3-git-send-email-bp@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/x86/include/asm/microcode.h     | 2 --
 arch/x86/kernel/cpu/microcode/core.c | 3 ++-
 arch/x86/mm/init.c                   | 7 -------
 3 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index ca2af7e..da0d81f 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 ac360bf..12823b6 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 372aad2..dffd162 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