blob: ab6343d21825d7d9328fae81fd6faef3bf092a13 [file] [log] [blame]
/*
* Performance events - AMD IBS
*
* Copyright (C) 2011 Advanced Micro Devices, Inc., Robert Richter
*
* For licencing details see kernel-base/COPYING
*/
#include <linux/perf_event.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <asm/apic.h>
static u32 ibs_caps;
#if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_AMD)
static struct pmu perf_ibs;
static int perf_ibs_init(struct perf_event *event)
{
if (perf_ibs.type != event->attr.type)
return -ENOENT;
return 0;
}
static int perf_ibs_add(struct perf_event *event, int flags)
{
return 0;
}
static void perf_ibs_del(struct perf_event *event, int flags)
{
}
static struct pmu perf_ibs = {
.event_init= perf_ibs_init,
.add= perf_ibs_add,
.del= perf_ibs_del,
};
static __init int perf_event_ibs_init(void)
{
if (!ibs_caps)
return -ENODEV; /* ibs not supported by the cpu */
perf_pmu_register(&perf_ibs, "ibs", -1);
printk(KERN_INFO "perf: AMD IBS detected (0x%08x)\n", ibs_caps);
return 0;
}
#else /* defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_AMD) */
static __init int perf_event_ibs_init(void) { return 0; }
#endif
/* IBS - apic initialization, for perf and oprofile */
static __init u32 __get_ibs_caps(void)
{
u32 caps;
unsigned int max_level;
if (!boot_cpu_has(X86_FEATURE_IBS))
return 0;
/* check IBS cpuid feature flags */
max_level = cpuid_eax(0x80000000);
if (max_level < IBS_CPUID_FEATURES)
return IBS_CAPS_DEFAULT;
caps = cpuid_eax(IBS_CPUID_FEATURES);
if (!(caps & IBS_CAPS_AVAIL))
/* cpuid flags not valid */
return IBS_CAPS_DEFAULT;
return caps;
}
u32 get_ibs_caps(void)
{
return ibs_caps;
}
EXPORT_SYMBOL(get_ibs_caps);
static inline int get_eilvt(int offset)
{
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);
}
/*
* Check and reserve APIC extended interrupt LVT offset for IBS if available.
*/
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;
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);
goto out;
}
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);
goto out;
}
valid = 1;
out:
preempt_enable();
return valid;
}
static int setup_ibs_ctl(int ibs_eilvt_off)
{
struct pci_dev *cpu_cfg;
int nodes;
u32 value = 0;
nodes = 0;
cpu_cfg = NULL;
do {
cpu_cfg = pci_get_device(PCI_VENDOR_ID_AMD,
PCI_DEVICE_ID_AMD_10H_NB_MISC,
cpu_cfg);
if (!cpu_cfg)
break;
++nodes;
pci_write_config_dword(cpu_cfg, IBSCTL, ibs_eilvt_off
| IBSCTL_LVT_OFFSET_VALID);
pci_read_config_dword(cpu_cfg, IBSCTL, &value);
if (value != (ibs_eilvt_off | IBSCTL_LVT_OFFSET_VALID)) {
pci_dev_put(cpu_cfg);
printk(KERN_DEBUG "Failed to setup IBS LVT offset, "
"IBSCTL = 0x%08x\n", value);
return -EINVAL;
}
} while (1);
if (!nodes) {
printk(KERN_DEBUG "No CPU node configured for IBS\n");
return -ENODEV;
}
return 0;
}
/*
* This runs only on the current cpu. We try to find an LVT offset and
* setup the local APIC. For this we must disable preemption. On
* success we initialize all nodes with this offset. This updates then
* the offset in the IBS_CTL per-node msr. The per-core APIC setup of
* the IBS interrupt vector is handled by perf_ibs_cpu_notifier that
* is using the new offset.
*/
static int force_ibs_eilvt_setup(void)
{
int offset;
int ret;
preempt_disable();
/* find the next free available EILVT entry, skip offset 0 */
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;
}
ret = setup_ibs_ctl(offset);
if (ret)
goto out;
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;
}
static inline int get_ibs_lvt_offset(void)
{
u64 val;
rdmsrl(MSR_AMD64_IBSCTL, val);
if (!(val & IBSCTL_LVT_OFFSET_VALID))
return -EINVAL;
return val & IBSCTL_LVT_OFFSET_MASK;
}
static void setup_APIC_ibs(void *dummy)
{
int offset;
offset = get_ibs_lvt_offset();
if (offset < 0)
goto failed;
if (!setup_APIC_eilvt(offset, 0, APIC_EILVT_MSG_NMI, 0))
return;
failed:
pr_warn("perf: IBS APIC setup failed on cpu #%d\n",
smp_processor_id());
}
static void clear_APIC_ibs(void *dummy)
{
int offset;
offset = get_ibs_lvt_offset();
if (offset >= 0)
setup_APIC_eilvt(offset, 0, APIC_EILVT_MSG_FIX, 1);
}
static int __cpuinit
perf_ibs_cpu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
{
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_STARTING:
setup_APIC_ibs(NULL);
break;
case CPU_DYING:
clear_APIC_ibs(NULL);
break;
default:
break;
}
return NOTIFY_OK;
}
static __init int amd_ibs_init(void)
{
u32 caps;
int ret;
caps = __get_ibs_caps();
if (!caps)
return -ENODEV; /* ibs not supported by the cpu */
if (!ibs_eilvt_valid()) {
ret = force_ibs_eilvt_setup();
if (ret) {
pr_err("Failed to setup IBS, %d\n", ret);
return ret;
}
}
get_online_cpus();
ibs_caps = caps;
/* make ibs_caps visible to other cpus: */
smp_mb();
perf_cpu_notifier(perf_ibs_cpu_notifier);
smp_call_function(setup_APIC_ibs, NULL, 1);
put_online_cpus();
return perf_event_ibs_init();
}
/* Since we need the pci subsystem to init ibs we can't do this earlier: */
device_initcall(amd_ibs_init);