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Patch "x86/boot/smp: Don't try to poke disabled/non-existent APIC" has been added to the 4.8-stable tree

PATCH [email protected] 1 participant 1 message Oct 26, 2016

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This is a note to let you know that I've just added the patch titled

x86/boot/smp: Don't try to poke disabled/non-existent APIC

to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-boot-smp-don-t-try-to-poke-disabled-non-existent-apic.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From ff8560512b8d4b7ca3ef4fd69166634ac30b2525 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <[email protected]>
Date: Sat, 22 Oct 2016 05:18:04 +0300
Subject: x86/boot/smp: Don't try to poke disabled/non-existent APIC
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Ville Syrjälä <[email protected]>

commit ff8560512b8d4b7ca3ef4fd69166634ac30b2525 upstream.

Apparently trying to poke a disabled or non-existent APIC leads to a box that doesn't even boot. Let's not do that.

No real clue if this is the right fix, but at least my P3 machine boots again.

Signed-off-by Ville Syrjälä <[email protected]>
Cc Andy Lutomirski <[email protected]>
Cc Borislav Petkov <[email protected]>
Cc Borislav Petkov <[email protected]>
Cc Brian Gerst <[email protected]>
Cc Denys Vlasenko <[email protected]>
Cc Eric Biederman <[email protected]>
Cc H. Peter Anvin <[email protected]>
Cc Jiri Olsa <[email protected]>
Cc Josh Poimboeuf <[email protected]>
Cc Juergen Gross <[email protected]>
Cc Len Brown <[email protected]>
Cc Linus Torvalds <[email protected]>
Cc Peter Zijlstra <[email protected]>
Cc Prarit Bhargava <[email protected]>
Cc Thomas Gleixner <[email protected]>
Cc Yinghai Lu <[email protected]>
Cc [email protected]
Cc [email protected]
Fixes 2a51fe083eba ("arch/x86: Handle non enumerated CPU after physical hotplug")
Link http://lkml.kernel.org/r/[email protected] open here
Signed-off-by Ingo Molnar <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 arch/x86/kernel/smpboot.c |   16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)
arch/x86/kernel/smpboot.c +9 -7
@@ -1408,15 +1408,17 @@ __init void prefill_possible_map(void)
 
 	/* No boot processor was found in mptable or ACPI MADT */
 	if (!num_processors) {
-		int apicid = boot_cpu_physical_apicid;
-		int cpu = hard_smp_processor_id();
+		if (boot_cpu_has(X86_FEATURE_APIC)) {
+			int apicid = boot_cpu_physical_apicid;
+			int cpu = hard_smp_processor_id();
 
-		pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu);
+			pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu);
 
-		/* Make sure boot cpu is enumerated */
-		if (apic->cpu_present_to_apicid(0) == BAD_APICID &&
-		    apic->apic_id_valid(apicid))
-			generic_processor_info(apicid, boot_cpu_apic_version);
+			/* Make sure boot cpu is enumerated */
+			if (apic->cpu_present_to_apicid(0) == BAD_APICID &&
+			    apic->apic_id_valid(apicid))
+				generic_processor_info(apicid, boot_cpu_apic_version);
+		}
 
 		if (!num_processors)
 			num_processors = 1;

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/x86-boot-smp-don-t-try-to-poke-disabled-non-existent-apic.patch queue-4.8/pinctrl-baytrail-fix-lockdep.patch