[kernel/f15] Add patch to ignore bogus io-apic entries (rhbz 801501)

[Josh Boyer]

commit ad6cae5b9e24ba8928c32462f78fbdffe8b85625
Author: Josh Boyer <jwboyer at redhat.com>
Date:   Mon Mar 12 09:19:54 2012 -0400

    Add patch to ignore bogus io-apic entries (rhbz 801501)

 kernel.spec                                        |    9 ++-
 ...register-checks-for-bogus-io-apic-entries.patch |   93 ++++++++++++++++++++
 2 files changed, 101 insertions(+), 1 deletions(-)
---
diff --git a/kernel.spec b/kernel.spec
index 7f6a2ca..11af568 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -42,7 +42,7 @@ Summary: The Linux kernel
 # When changing real_sublevel below, reset this by hand to 1
 # (or to 0 and then use rpmdev-bumpspec).
 #
-%global baserelease 3
+%global baserelease 4
 %global fedora_build %{baserelease}
 
 # real_sublevel is the 3.x kernel version we're starting with
@@ -734,6 +734,8 @@ Patch21108: mm-thp-fix-BUG-on-mm-nr_ptes.patch
 #rhbz 800817
 Patch21109: mm-memcg-Correct-unregistring-of-events-attached-to-.patch
 
+Patch21110: x86-ioapic-add-register-checks-for-bogus-io-apic-entries.patch
+
 Patch21200: unhandled-irqs-switch-to-polling.patch
 
 Patch22000: weird-root-dentry-name-debug.patch
@@ -1367,6 +1369,8 @@ ApplyPatch mm-thp-fix-BUG-on-mm-nr_ptes.patch
 #rhbz 800817
 ApplyPatch mm-memcg-Correct-unregistring-of-events-attached-to-.patch
 
+ApplyPatch x86-ioapic-add-register-checks-for-bogus-io-apic-entries.patch
+
 # END OF PATCH APPLICATIONS
 
 %endif
@@ -2014,6 +2018,9 @@ fi
 # and build.
 
 %changelog
+* Mon Mar 12 2012 Josh Boyer <jwboyer at redhat.com>
+- Add patch to ignore bogus io-apic entries (rhbz 801501)
+
 * Wed Mar 07 2012 Dave Jones <davej at redhat.com>
 - Add debug patch for bugs 787171/766277
 
diff --git a/x86-ioapic-add-register-checks-for-bogus-io-apic-entries.patch b/x86-ioapic-add-register-checks-for-bogus-io-apic-entries.patch
new file mode 100644
index 0000000..9928829
--- /dev/null
+++ b/x86-ioapic-add-register-checks-for-bogus-io-apic-entries.patch
@@ -0,0 +1,93 @@
+On Tue, 2012-01-31 at 09:26 -0500, Josh Boyer wrote:
+> On Wed, Jan 25, 2012 at 06:15:35PM -0500, Josh Boyer wrote:
+> > On Wed, Jan 25, 2012 at 02:04:08PM -0800, Suresh Siddha wrote:
+> > > On Wed, 2012-01-25 at 08:49 -0500, Josh Boyer wrote:
+> > > > [    0.000000] IOAPIC[1]: apic_id 2, version 255, address 0xfec28000, GSI 24-279
+> > > 
+> > > This looks indeed like a bogus entry probably returning all 1's for
+> > > RTE's etc. Can you please send me a dmesg with "apic=verbose" boot
+> > > parameter?
+> > 
+> > Here you go:
+> > 
+> > https://bugzilla.redhat.com/attachment.cgi?id=557552
+> 
+> Was this helpful at all?  I've been watching lkml for a related patch
+> in case I was missed on CC but haven't seen anything as of yet.
+
+Yes, it was helpful. Something like the appended patch should ignore the
+bogus io-apic entry all together. As I can't test this, can you or the
+reporter give the appended patch a try and ack please?
+
+thanks,
+suresh
+---
+
+From: Suresh Siddha <suresh.b.siddha at intel.com>
+Subject: x86, ioapic: add register checks for bogus io-apic entries
+
+With the recent changes to clear_IO_APIC_pin() which tries to clear
+remoteIRR bit explicitly, some of the users started to see
+"Unable to reset IRR for apic .." messages.
+
+Close look shows that these are related to bogus IO-APIC entries which
+return's all 1's for their io-apic registers. And the above mentioned error
+messages are benign. But kernel should have ignored such io-apic's in the
+first place.
+
+Check if register 0, 1, 2 of the listed io-apic are all 1's and ignore
+such io-apic.
+
+Reported-by: Álvaro Castillo <midgoon at gmail.com>
+Signed-off-by: Suresh Siddha <suresh.b.siddha at intel.com>
+---
+ arch/x86/kernel/apic/io_apic.c |   26 ++++++++++++++++++++++++++
+ 1 files changed, 26 insertions(+), 0 deletions(-)
+
+diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
+index fb07275..953e54d 100644
+--- a/arch/x86/kernel/apic/io_apic.c
++++ b/arch/x86/kernel/apic/io_apic.c
+@@ -3979,6 +3979,26 @@ static __init int bad_ioapic(unsigned long address)
+ 	return 0;
+ }
+ 
++static __init int bad_ioapic_regs(int idx)
++{
++	union IO_APIC_reg_00 reg_00;
++	union IO_APIC_reg_01 reg_01;
++	union IO_APIC_reg_02 reg_02;
++
++	reg_00.raw = io_apic_read(idx, 0);
++	reg_01.raw = io_apic_read(idx, 1);
++	reg_02.raw = io_apic_read(idx, 2);
++
++	if (reg_00.raw == -1 && reg_01.raw == -1 && reg_02.raw == -1) {
++		printk(KERN_WARNING
++		       "I/O APIC 0x%x regs return all ones, skipping!\n",
++		       mpc_ioapic_addr(idx));
++		return 1;
++	}
++
++	return 0;
++}
++
+ void __init mp_register_ioapic(int id, u32 address, u32 gsi_base)
+ {
+ 	int idx = 0;
+@@ -3995,6 +4015,12 @@ void __init mp_register_ioapic(int id, u32 address, u32 gsi_base)
+ 	ioapics[idx].mp_config.apicaddr = address;
+ 
+ 	set_fixmap_nocache(FIX_IO_APIC_BASE_0 + idx, address);
++
++	if (bad_ioapic_regs(idx)) {
++		clear_fixmap(FIX_IO_APIC_BASE_0 + idx);
++		return;
++	}
++
+ 	ioapics[idx].mp_config.apicid = io_apic_unique_id(id);
+ 	ioapics[idx].mp_config.apicver = io_apic_get_version(idx);
+ 
+
+
+