Commit 3d2606f4 authored by Robert Richter's avatar Robert Richter
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oprofile, x86: Enable preemption during pci device setup in IBS init 



IBS initialization is a mix of per-core register access and per-node
pci device setup. Register access should be pinned to the cpu, but pci
setup must run with preemption enabled.

This patch better separates the code into non-/preemptible sections
and fixes sleeping with preemption disabled. See bug message below.

Fixes also freeing the eilvt entry by introducing put_eilvt().

BUG: sleeping function called from invalid context at mm/slub.c:824
in_atomic(): 1, irqs_disabled(): 0, pid: 32357, name: modprobe
INFO: lockdep is turned off.
Pid: 32357, comm: modprobe Not tainted 2.6.39-rc7+ #14
Call Trace:
 [<ffffffff8104bdc8>] __might_sleep+0x112/0x117
 [<ffffffff81129693>] kmem_cache_alloc_trace+0x4b/0xe7
 [<ffffffff81278f14>] kzalloc.constprop.0+0x29/0x2b
 [<ffffffff81278f4c>] pci_get_subsys+0x36/0x78
 [<ffffffff81022689>] ? setup_APIC_eilvt+0xfb/0x139
 [<ffffffff81278fa4>] pci_get_device+0x16/0x18
 [<ffffffffa06c8b5d>] op_amd_init+0xd3/0x211 [oprofile]
 [<ffffffffa064d000>] ? 0xffffffffa064cfff
 [<ffffffffa064d298>] op_nmi_init+0x21e/0x26a [oprofile]
 [<ffffffffa064d062>] oprofile_arch_init+0xe/0x26 [oprofile]
 [<ffffffffa064d010>] oprofile_init+0x10/0x42 [oprofile]
 [<ffffffff81002099>] do_one_initcall+0x7f/0x13a
 [<ffffffff81096524>] sys_init_module+0x132/0x281
 [<ffffffff814cc682>] system_call_fastpath+0x16/0x1b

Reported-by: default avatarDave Jones <davej@redhat.com>
Cc: <stable@kernel.org>         [2.6.37.x]
Signed-off-by: default avatarRobert Richter <robert.richter@amd.com>
parent 61c4f2c8

arch/x86/oprofile/op_model_amd.c

+54 −41
Original line number Diff line number Diff line
@@ -316,16 +316,23 @@ static void op_amd_stop_ibs(void) 
		wrmsrl(MSR_AMD64_IBSOPCTL, 0);

}



static inline int eilvt_is_available(int offset)

static inline int get_eilvt(int offset)

{

	/* check if we may assign a vector */

	return !setup_APIC_eilvt(offset, 0, APIC_EILVT_MSG_NMI, 1);

}



static inline int put_eilvt(int offset)

{

	return !setup_APIC_eilvt(offset, 0, 0, 1);

}



static inline int ibs_eilvt_valid(void)

{

	int offset;

	u64 val;

	int valid = 0;



	preempt_disable();



	rdmsrl(MSR_AMD64_IBSCTL, val);

	offset = val & IBSCTL_LVT_OFFSET_MASK;
@@ -333,16 +340,20 @@ static inline int ibs_eilvt_valid(void) 
	if (!(val & IBSCTL_LVT_OFFSET_VALID)) {

		pr_err(FW_BUG "cpu %d, invalid IBS interrupt offset %d (MSR%08X=0x%016llx)\n",

		       smp_processor_id(), offset, MSR_AMD64_IBSCTL, val);

		return 0;

		goto out;

	}



	if (!eilvt_is_available(offset)) {

	if (!get_eilvt(offset)) {

		pr_err(FW_BUG "cpu %d, IBS interrupt offset %d not available (MSR%08X=0x%016llx)\n",

		       smp_processor_id(), offset, MSR_AMD64_IBSCTL, val);

		return 0;

		goto out;

	}



	return 1;

	valid = 1;

out:

	preempt_enable();



	return valid;

}



static inline int get_ibs_offset(void)
@@ -600,67 +611,69 @@ static int setup_ibs_ctl(int ibs_eilvt_off) 


static int force_ibs_eilvt_setup(void)

{

	int i;

	int offset;

	int ret;



	/* find the next free available EILVT entry */

	for (i = 1; i < 4; i++) {

		if (!eilvt_is_available(i))

			continue;

		ret = setup_ibs_ctl(i);

		if (ret)

			return ret;

		pr_err(FW_BUG "using offset %d for IBS interrupts\n", i);

		return 0;

	/*

	 * find the next free available EILVT entry, skip offset 0,

	 * pin search to this cpu

	 */

	preempt_disable();

	for (offset = 1; offset < APIC_EILVT_NR_MAX; offset++) {

		if (get_eilvt(offset))

			break;

	}

	preempt_enable();



	if (offset == APIC_EILVT_NR_MAX) {

		printk(KERN_DEBUG "No EILVT entry available\n");



		return -EBUSY;

	}



static int __init_ibs_nmi(void)

{

	int ret;



	if (ibs_eilvt_valid())

		return 0;



	ret = force_ibs_eilvt_setup();

	ret = setup_ibs_ctl(offset);

	if (ret)

		return ret;

		goto out;



	if (!ibs_eilvt_valid())

		return -EFAULT;

	if (!ibs_eilvt_valid()) {

		ret = -EFAULT;

		goto out;

	}



	pr_err(FW_BUG "using offset %d for IBS interrupts\n", offset);

	pr_err(FW_BUG "workaround enabled for IBS LVT offset\n");



	return 0;

out:

	preempt_disable();

	put_eilvt(offset);

	preempt_enable();

	return ret;

}



/*

 * 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)

{

	preempt_disable();



	ibs_caps = get_ibs_caps();



	if (!ibs_caps)

		return;



	if (ibs_eilvt_valid())

		goto out;



	if (__init_ibs_nmi() < 0)

	if (!force_ibs_eilvt_setup())

		goto out;



	/* Failed to setup ibs */

	ibs_caps = 0;

	else

		printk(KERN_INFO "oprofile: AMD IBS detected (0x%08x)\n", ibs_caps);

	return;



out:

	preempt_enable();

	printk(KERN_INFO "oprofile: AMD IBS detected (0x%08x)\n", ibs_caps);

}



static int (*create_arch_files)(struct super_block *sb, struct dentry *root);

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