From 1c0a5b6e4133263d5ae07ff7a2a02134f0cf07bf Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Mon, 3 Jan 2011 12:15:14 +0100 Subject: [PATCH] arch/x86/oprofile/op_model_amd.c: Perform initialisation on a single CPU Disable preemption in init_ibs(). The function only checks the ibs capabilities and sets up pci devices (if necessary). It runs only on one cpu but operates with the local APIC and some MSRs, thus it is better to disable preemption. [ 7.034377] BUG: using smp_processor_id() in preemptible [00000000] code: modprobe/483 [ 7.034385] caller is setup_APIC_eilvt+0x155/0x180 [ 7.034389] Pid: 483, comm: modprobe Not tainted 2.6.37-rc1-20101110+ #1 [ 7.034392] Call Trace: [ 7.034400] [] debug_smp_processor_id+0xd2/0xf0 [ 7.034404] [] setup_APIC_eilvt+0x155/0x180 [ ... ] Addresses https://bugzilla.kernel.org/show_bug.cgi?id=22812 Reported-by: Signed-off-by: Robert Richter Cc: oprofile-list@lists.sourceforge.net Cc: Peter Zijlstra Cc: Frederic Weisbecker Cc: Rafael J. Wysocki Cc: Dan Carpenter Cc: Andrew Morton Cc: [2.6.37.x] LKML-Reference: <20110103111514.GM4739@erda.amd.com> [ small cleanups ] Signed-off-by: Ingo Molnar --- arch/x86/oprofile/op_model_amd.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/arch/x86/oprofile/op_model_amd.c b/arch/x86/oprofile/op_model_amd.c index a011bcc0f9433..7d90d47655ba3 100644 --- a/arch/x86/oprofile/op_model_amd.c +++ b/arch/x86/oprofile/op_model_amd.c @@ -630,21 +630,29 @@ static int __init_ibs_nmi(void) return 0; } -/* initialize the APIC for the IBS interrupts if available */ +/* + * check and reserve APIC extended interrupt LVT offset for IBS if + * available + * + * init_ibs() preforms implicitly cpu-local operations, so pin this + * thread to its current CPU + */ + static void init_ibs(void) { - ibs_caps = get_ibs_caps(); + preempt_disable(); + ibs_caps = get_ibs_caps(); if (!ibs_caps) - return; + goto out; - if (__init_ibs_nmi()) { + if (__init_ibs_nmi() < 0) ibs_caps = 0; - return; - } + else + printk(KERN_INFO "oprofile: AMD IBS detected (0x%08x)\n", ibs_caps); - printk(KERN_INFO "oprofile: AMD IBS detected (0x%08x)\n", - (unsigned)ibs_caps); +out: + preempt_enable(); } static int (*create_arch_files)(struct super_block *sb, struct dentry *root); -- 2.39.5