core2 rdtsc sync fix from arjan for 2.6.18 also

diff --git a/queue-2.6.18/series b/queue-2.6.18/series
index b21cdc17bb528e4d9b29cbc4164300320fa892ad..9a9121825c7a44efbc8345f4a4532ee3d7efd395 100644 (file)
--- a/queue-2.6.18/series
+++ b/queue-2.6.18/series
@@ -22,3 +22,4 @@ softirq-remove-bug_ons-which-can-incorrectly-trigger.patch
 m32r-make-userspace-headers-platform-independent.patch
 forcedeth-disable-intx-when-enabling-msi-in-forcedeth.patch
 bluetooth-add-packet-size-checks-for-capi-messages.patch
+x86-64-mark-rdtsc-as-sync-only-for-netburst-not-for-core2.patch

diff --git a/queue-2.6.18/x86-64-mark-rdtsc-as-sync-only-for-netburst-not-for-core2.patch b/queue-2.6.18/x86-64-mark-rdtsc-as-sync-only-for-netburst-not-for-core2.patch
new file mode 100644 (file)
index 0000000..e766b53
--- /dev/null
+++ b/queue-2.6.18/x86-64-mark-rdtsc-as-sync-only-for-netburst-not-for-core2.patch
@@ -0,0 +1,44 @@
+From stable-bounces@linux.kernel.org  Mon Dec 11 13:26:59 2006
+From: Arjan van de Ven <arjan@linux.intel.com>
+To: stable@kernel.org
+Date: Mon, 11 Dec 2006 21:45:01 +0100
+Message-Id: <1165869901.27217.439.camel@laptopd505.fenrus.org>
+Subject: x86-64: Mark rdtsc as sync only for netburst, not for core2
+
+On the Core2 cpus, the rdtsc instruction is not serializing (as defined
+in the architecture reference since rdtsc exists) and due to the deep
+speculation of these cores, it's possible that you can observe time go
+backwards between cores due to this speculation. Since the kernel
+already deals with this with the SYNC_RDTSC flag, the solution is
+simple, only assume that the instruction is serializing on family 15...
+
+The price one pays for this is a slightly slower gettimeofday (by a
+dozen or two cycles), but that increase is quite small to pay for a
+really-going-forward tsc counter.
+
+Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
+Signed-off-by: Andi Kleen <ak@suse.de>
+[chrisw: backported to 2.6.18]
+Signed-off-by: Chris Wright <chrisw@sous-sol.org>
+---
+Commit:     f3d73707a1e84f0687a05144b70b660441e999c7
+Author:     Arjan van de Ven <arjan@linux.intel.com>
+Date:       Thu Dec 7 02:14:12 2006 +0100
+
+ arch/x86_64/kernel/setup.c |    5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+--- linux-2.6.18.5.orig/arch/x86_64/kernel/setup.c
++++ linux-2.6.18.5/arch/x86_64/kernel/setup.c
+@@ -1010,7 +1010,10 @@ static void __cpuinit init_intel(struct 
+       if ((c->x86 == 0xf && c->x86_model >= 0x03) ||
+           (c->x86 == 0x6 && c->x86_model >= 0x0e))
+               set_bit(X86_FEATURE_CONSTANT_TSC, &c->x86_capability);
+-      set_bit(X86_FEATURE_SYNC_RDTSC, &c->x86_capability);
++      if (c->x86 == 15)
++              set_bit(X86_FEATURE_SYNC_RDTSC, &c->x86_capability);
++      else
++              clear_bit(X86_FEATURE_SYNC_RDTSC, &c->x86_capability);
+       c->x86_max_cores = intel_num_cpu_cores(c);
+ 
+       srat_detect_node();