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authorSuresh Siddha <suresh.b.siddha@intel.com>2009-08-19 21:05:36 -0400
committerH. Peter Anvin <hpa@zytor.com>2009-08-21 19:25:55 -0400
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')
-rw-r--r--arch/x86/power/cpu.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index b3d20b9cac63..417c9f5b4afa 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)
242 fix_processor_context(); 242 fix_processor_context();
243 243
244 do_fpu_end(); 244 do_fpu_end();
245 mtrr_ap_init(); 245 mtrr_bp_restore();
246 246
247#ifdef CONFIG_X86_OLD_MCE 247#ifdef CONFIG_X86_OLD_MCE
248 mcheck_init(&boot_cpu_data); 248 mcheck_init(&boot_cpu_data);