replace x86_64 boot hang nmi fix with the one that's upstream.

diff --git a/review-2.6.19/x86_64-fix-boot-hang-due-to-nmi-watchdog-init-code.patch b/review-2.6.19/x86_64-fix-boot-hang-due-to-nmi-watchdog-init-code.patch
index 3661d6db89e8e9d002a9cca2ddd06a118e18094e..232e316483eabf8e71c0661a48462b657862599a 100644 (file)
--- a/review-2.6.19/x86_64-fix-boot-hang-due-to-nmi-watchdog-init-code.patch
+++ b/review-2.6.19/x86_64-fix-boot-hang-due-to-nmi-watchdog-init-code.patch
@@ -1,50 +1,99 @@
-From stable-bounces@linux.kernel.org  Fri Dec  8 03:26:13 2006
-Message-Id: <200612081120.kB8BKZqK019065@shell0.pdx.osdl.net>
-To: ak@muc.de
-From: akpm@osdl.org
-Date: Fri, 08 Dec 2006 03:20:34 -0800
-Cc: akpm@osdl.org, shai@scalex86.org, stable@kernel.org, kiran@scalex86.org
-Subject: x86_64: fix boot hang due to nmi watchdog init code
-
+From 92715e282be7c7488f892703c8d39b08976a833b Mon Sep 17 00:00:00 2001
 From: Ravikiran G Thirumalai <kiran@scalex86.org>
+Date: Sat, 9 Dec 2006 21:33:35 +0100
+Subject: x86: Fix boot hang due to nmi watchdog init code
 
-2.6.19 stopped booting (or booted based on build/config) on our x86_64
+2.6.19  stopped booting (or booted based on build/config) on our x86_64
 systems due to a bug introduced in 2.6.19.  check_nmi_watchdog schedules an
-IPI on all cpus to busy wait on a flag, but fails to set the busywait flag
-if NMI functionality is disabled.
-
-This causes the secondary cpus to spin in an endless loop, causing the
-kernel bootup to hang.
+IPI on all cpus to  busy wait on a flag, but fails to set the busywait
+flag if NMI functionality is disabled.  This causes the secondary cpus
+to spin in an endless loop, causing the kernel bootup to hang.
+Depending upon the build, the  busywait flag got overwritten (stack variable)
+and caused  the kernel to bootup on certain builds.  Following patch fixes
+the bug by setting the busywait flag before returning from check_nmi_watchdog.
+I guess using a stack variable is not good here as the calling function could
+potentially return while the busy wait loop is still spinning on the flag.
 
-Depending upon the build, the busywait flag got overwritten (stack
-variable) and caused the kernel to bootup on certain builds.  Following
-patch fixes the bug by setting the busywait flag before returning from
-check_nmi_watchdog.
+AK: I redid the patch significantly to be cleaner
 
-I guess using a stack variable is not good here as the calling function
-could potentially return while the busy wait loop is still spinning on the
-flag.  I would think this is a good candidate for 2.6.19 stable as well.
-
-[akpm@osdl.org: cleanups]
 Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
 Signed-off-by: Shai Fultheim <shai@scalex86.org>
-Cc: Andi Kleen <ak@muc.de>
-Cc: <stable@kernel.org>
-Signed-off-by: Andrew Morton <akpm@osdl.org>
+Signed-off-by: Andi Kleen <ak@suse.de>
 Signed-off-by: Chris Wright <chrisw@sous-sol.org>
 ---
+ arch/i386/kernel/nmi.c   |    8 ++++----
+ arch/x86_64/kernel/nmi.c |    9 +++++----
+ 2 files changed, 9 insertions(+), 8 deletions(-)
 
- arch/x86_64/kernel/nmi.c |    3 ++-
- 1 file changed, 2 insertions(+), 1 deletion(-)
-
+--- linux-2.6.19.orig/arch/i386/kernel/nmi.c
++++ linux-2.6.19/arch/i386/kernel/nmi.c
+@@ -192,6 +192,8 @@ static __cpuinit inline int nmi_known_cp
+       return 0;
+ }
+ 
++static int endflag __initdata = 0;
++
+ #ifdef CONFIG_SMP
+ /* The performance counters used by NMI_LOCAL_APIC don't trigger when
+  * the CPU is idle. To make sure the NMI watchdog really ticks on all
+@@ -199,7 +201,6 @@ static __cpuinit inline int nmi_known_cp
+  */
+ static __init void nmi_cpu_busy(void *data)
+ {
+-      volatile int *endflag = data;
+       local_irq_enable_in_hardirq();
+       /* Intentionally don't use cpu_relax here. This is
+          to make sure that the performance counter really ticks,
+@@ -207,14 +208,13 @@ static __init void nmi_cpu_busy(void *da
+          pause instruction. On a real HT machine this is fine because
+          all other CPUs are busy with "useless" delay loops and don't
+          care if they get somewhat less cycles. */
+-      while (*endflag == 0)
+-              barrier();
++      while (endflag == 0)
++              mb();
+ }
+ #endif
+ 
+ static int __init check_nmi_watchdog(void)
+ {
+-      volatile int endflag = 0;
+       unsigned int *prev_nmi_count;
+       int cpu;
+ 
 --- linux-2.6.19.orig/arch/x86_64/kernel/nmi.c
 +++ linux-2.6.19/arch/x86_64/kernel/nmi.c
-@@ -212,7 +212,7 @@ static __init void nmi_cpu_busy(void *da
+@@ -190,6 +190,8 @@ void nmi_watchdog_default(void)
+               nmi_watchdog = NMI_IO_APIC;
+ }
+ 
++static int endflag __initdata = 0;
++
+ #ifdef CONFIG_SMP
+ /* The performance counters used by NMI_LOCAL_APIC don't trigger when
+  * the CPU is idle. To make sure the NMI watchdog really ticks on all
+@@ -197,7 +199,6 @@ void nmi_watchdog_default(void)
+  */
+ static __init void nmi_cpu_busy(void *data)
+ {
+-      volatile int *endflag = data;
+       local_irq_enable_in_hardirq();
+       /* Intentionally don't use cpu_relax here. This is
+          to make sure that the performance counter really ticks,
+@@ -205,14 +206,13 @@ static __init void nmi_cpu_busy(void *da
+          pause instruction. On a real HT machine this is fine because
+          all other CPUs are busy with "useless" delay loops and don't
+          care if they get somewhat less cycles. */
+-      while (*endflag == 0)
+-              barrier();
++      while (endflag == 0)
++              mb();
+ }
+ #endif
  
  int __init check_nmi_watchdog (void)
  {
 -      volatile int endflag = 0;
-+      static int __initdata endflag;
        int *counts;
        int cpu;