path: root/arch/x86/power
diff options
authorSuresh Siddha <suresh.b.siddha@intel.com>2009-08-19 18:05:36 -0700
committerH. Peter Anvin <hpa@zytor.com>2009-08-21 16:25:55 -0700
commitd0af9eed5aa91b6b7b5049cae69e5ea956fd85c3 (patch)
treeb9214db00ba734e5b943165082c30336f7a8425a /arch/x86/power
parent269c861baa2fe7c114c3bc7831292758d29eb336 (diff)
x86, pat/mtrr: Rendezvous all the cpus for MTRR/PAT init
SDM Vol 3a section titled "MTRR considerations in MP systems" specifies the need for synchronizing the logical cpu's while initializing/updating MTRR. Currently Linux kernel does the synchronization of all cpu's only when a single MTRR register is programmed/updated. During an AP online (during boot/cpu-online/resume) where we initialize all the MTRR/PAT registers, we don't follow this synchronization algorithm. This can lead to scenarios where during a dynamic cpu online, that logical cpu is initializing MTRR/PAT with cache disabled (cr0.cd=1) etc while other logical HT sibling continue to run (also with cache disabled because of cr0.cd=1 on its sibling). Starting from Westmere, VMX transitions with cr0.cd=1 don't work properly (because of some VMX performance optimizations) and the above scenario (with one logical cpu doing VMX activity and another logical cpu coming online) can result in system crash. Fix the MTRR initialization by doing rendezvous of all the cpus. During boot and resume, we delay the MTRR/PAT init for APs till all the logical cpu's come online and the rendezvous process at the end of AP's bringup, will initialize the MTRR/PAT for all AP's. For dynamic single cpu online, we synchronize all the logical cpus and do the MTRR/PAT init on the AP that is coming online. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/power')
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index b3d20b9cac6..417c9f5b4af 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -242,7 +242,7 @@ static void __restore_processor_state(struct saved_context *ctxt)
- mtrr_ap_init();
+ mtrr_bp_restore();