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From: Borislav Petkov <bp@alien8.de>
To: X86 ML <x86@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH 01/12] x86/microcode: Run the AP-loading routine only on the application processors
Date: Tue, 25 Oct 2016 11:55:11 +0200	[thread overview]
Message-ID: <20161025095522.11964-2-bp@alien8.de> (raw)
In-Reply-To: <20161025095522.11964-1-bp@alien8.de>

From: Borislav Petkov <bp@suse.de>

cpu_init() is run also on the BSP (in addition to the APs):

x86_64_start_kernel
|-> x86_64_start_reservations
|-> start_kernel
|-> trap_init
|-> cpu_init
|-> load_ucode_ap
...

but we run the AP (Application Processors) microcode loading routine
there too even though we have a BSP-specific routine for that:
load_ucode_bsp().

Which is unnecessary. So let's limit the AP microcode loading routine to
the APs only.

Remove a useless comment while at it.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/kernel/cpu/common.c        | 7 ++-----
 arch/x86/kernel/cpu/microcode/amd.c | 5 -----
 2 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 9bd910a7dd0a..1a1d668263b9 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1462,11 +1462,8 @@ void cpu_init(void)
 	 */
 	cr4_init_shadow();
 
-	/*
-	 * Load microcode on this cpu if a valid microcode is available.
-	 * This is early microcode loading procedure.
-	 */
-	load_ucode_ap();
+	if (cpu)
+		load_ucode_ap();
 
 	t = &per_cpu(cpu_tss, cpu);
 	oist = &per_cpu(orig_ist, cpu);
diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 620ab06bcf45..6b3929e80fd4 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -357,17 +357,12 @@ static void __init get_bsp_sig(void)
 #else
 void load_ucode_amd_ap(void)
 {
-	unsigned int cpu = smp_processor_id();
 	struct equiv_cpu_entry *eq;
 	struct microcode_amd *mc;
 	u8 *cont = container;
 	u32 rev, eax;
 	u16 eq_id;
 
-	/* Exit if called on the BSP. */
-	if (!cpu)
-		return;
-
 	if (!container)
 		return;
 
-- 
2.10.0

  reply	other threads:[~2016-10-25  9:57 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-25  9:55 [PATCH 00/12] x86/microcode: Rework microcode loading Borislav Petkov
2016-10-25  9:55 ` Borislav Petkov [this message]
2016-10-25 16:27   ` [tip:x86/microcode] x86/microcode: Run the AP-loading routine only on the application processors tip-bot for Borislav Petkov
2016-10-25  9:55 ` [PATCH 02/12] x86/microcode: Move driver authors to CREDITS Borislav Petkov
2016-10-25 16:28   ` [tip:x86/microcode] " tip-bot for Borislav Petkov
2016-10-25  9:55 ` [PATCH 03/12] x86/microcode/intel: Simplify generic_load_microcode() Borislav Petkov
2016-10-25 16:28   ` [tip:x86/microcode] " tip-bot for Borislav Petkov
2016-10-25  9:55 ` [PATCH 04/12] x86/microcode: Remove one ifdef clause Borislav Petkov
2016-10-25 16:29   ` [tip:x86/microcode] x86/microcode: Remove one #ifdef clause tip-bot for Borislav Petkov
2016-10-25  9:55 ` [PATCH 05/12] x86/microcode: Export the microcode cache linked list Borislav Petkov
2016-10-25 16:29   ` [tip:x86/microcode] " tip-bot for Borislav Petkov
2016-10-25  9:55 ` [PATCH 06/12] x86/microcode/AMD: Hand down the CPU family Borislav Petkov
2016-10-25 16:30   ` [tip:x86/microcode] x86/microcode/amd: " tip-bot for Borislav Petkov
2016-10-25  9:55 ` [PATCH 07/12] x86/microcode: Issue the debug printk on resume only on success Borislav Petkov
2016-10-25 16:30   ` [tip:x86/microcode] " tip-bot for Borislav Petkov
2016-10-25  9:55 ` [PATCH 08/12] x86/microcode: Collect CPU info on resume Borislav Petkov
2016-10-25 16:31   ` [tip:x86/microcode] " tip-bot for Borislav Petkov
2016-10-25  9:55 ` [PATCH 09/12] x86/microcode/AMD: Retract functions Borislav Petkov
2016-10-25 16:31   ` [tip:x86/microcode] x86/microcode/amd: Move private inlines to .c and mark local functions static tip-bot for Borislav Petkov
2016-10-25  9:55 ` [PATCH 10/12] x86/microcode/intel: Remove intel_lib.c Borislav Petkov
2016-10-25 16:32   ` [tip:x86/microcode] " tip-bot for Borislav Petkov
2016-10-25  9:55 ` [PATCH 11/12] x86/microcode: Rework microcode loading Borislav Petkov
2016-10-25 16:32   ` [tip:x86/microcode] " tip-bot for Borislav Petkov
2016-10-25  9:55 ` [PATCH 12/12] x86/microcode: Bump driver version, update copyrights Borislav Petkov
2016-10-25 16:33   ` [tip:x86/microcode] " tip-bot for Borislav Petkov

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