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linux/arch/powerpc/perf/core-book3s.c

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/*
* Performance event support - powerpc architecture code
*
* Copyright 2008-2009 Paul Mackerras, IBM Corporation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/perf_event.h>
#include <linux/percpu.h>
#include <linux/hardirq.h>
#include <linux/uaccess.h>
#include <asm/reg.h>
#include <asm/pmc.h>
#include <asm/machdep.h>
#include <asm/firmware.h>
#include <asm/ptrace.h>
#include <asm/code-patching.h>
#define BHRB_MAX_ENTRIES 32
#define BHRB_TARGET 0x0000000000000002
#define BHRB_PREDICTION 0x0000000000000001
#define BHRB_EA 0xFFFFFFFFFFFFFFFCUL
struct cpu_hw_events {
int n_events;
int n_percpu;
int disabled;
int n_added;
int n_limited;
u8 pmcs_enabled;
struct perf_event *event[MAX_HWEVENTS];
u64 events[MAX_HWEVENTS];
unsigned int flags[MAX_HWEVENTS];
unsigned long mmcr[3];
struct perf_event *limited_counter[MAX_LIMITED_HWCOUNTERS];
u8 limited_hwidx[MAX_LIMITED_HWCOUNTERS];
u64 alternatives[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES];
unsigned long amasks[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES];
unsigned long avalues[MAX_HWEVENTS][MAX_EVENT_ALTERNATIVES];
unsigned int group_flag;
int n_txn_start;
/* BHRB bits */
u64 bhrb_filter; /* BHRB HW branch filter */
int bhrb_users;
void *bhrb_context;
struct perf_branch_stack bhrb_stack;
struct perf_branch_entry bhrb_entries[BHRB_MAX_ENTRIES];
};
DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
struct power_pmu *ppmu;
/*
* Normally, to ignore kernel events we set the FCS (freeze counters
* in supervisor mode) bit in MMCR0, but if the kernel runs with the
* hypervisor bit set in the MSR, or if we are running on a processor
* where the hypervisor bit is forced to 1 (as on Apple G5 processors),
* then we need to use the FCHV bit to ignore kernel events.
*/
static unsigned int freeze_events_kernel = MMCR0_FCS;
/*
* 32-bit doesn't have MMCRA but does have an MMCR2,
* and a few other names are different.
*/
#ifdef CONFIG_PPC32
#define MMCR0_FCHV 0
#define MMCR0_PMCjCE MMCR0_PMCnCE
#define MMCR0_FC56 0
#define MMCR0_PMAO 0
#define MMCR0_EBE 0
#define MMCR0_BHRBA 0
#define MMCR0_PMCC 0
#define MMCR0_PMCC_U6 0
#define SPRN_MMCRA SPRN_MMCR2
#define MMCRA_SAMPLE_ENABLE 0
static inline unsigned long perf_ip_adjust(struct pt_regs *regs)
{
return 0;
}
static inline void perf_get_data_addr(struct pt_regs *regs, u64 *addrp) { }
static inline u32 perf_get_misc_flags(struct pt_regs *regs)
{
return 0;
}
static inline void perf_read_regs(struct pt_regs *regs)
{
regs->result = 0;
}
static inline int perf_intr_is_nmi(struct pt_regs *regs)
{
return 0;
}
static inline int siar_valid(struct pt_regs *regs)
{
return 1;
}
static bool is_ebb_event(struct perf_event *event) { return false; }
static int ebb_event_check(struct perf_event *event) { return 0; }
static void ebb_event_add(struct perf_event *event) { }
static void ebb_switch_out(unsigned long mmcr0) { }
static unsigned long ebb_switch_in(bool ebb, unsigned long mmcr0)
{
return mmcr0;
}
static inline void power_pmu_bhrb_enable(struct perf_event *event) {}
static inline void power_pmu_bhrb_disable(struct perf_event *event) {}
void power_pmu_flush_branch_stack(void) {}
static inline void power_pmu_bhrb_read(struct cpu_hw_events *cpuhw) {}
static void pmao_restore_workaround(bool ebb) { }
#endif /* CONFIG_PPC32 */
static bool regs_use_siar(struct pt_regs *regs)
{
return !!regs->result;
}
/*
* Things that are specific to 64-bit implementations.
*/
#ifdef CONFIG_PPC64
static inline unsigned long perf_ip_adjust(struct pt_regs *regs)
{
unsigned long mmcra = regs->dsisr;
if ((ppmu->flags & PPMU_HAS_SSLOT) && (mmcra & MMCRA_SAMPLE_ENABLE)) {
unsigned long slot = (mmcra & MMCRA_SLOT) >> MMCRA_SLOT_SHIFT;
if (slot > 1)
return 4 * (slot - 1);
}
return 0;
}
/*
* The user wants a data address recorded.
* If we're not doing instruction sampling, give them the SDAR
* (sampled data address). If we are doing instruction sampling, then
* only give them the SDAR if it corresponds to the instruction
* pointed to by SIAR; this is indicated by the [POWER6_]MMCRA_SDSYNC, the
* [POWER7P_]MMCRA_SDAR_VALID bit in MMCRA, or the SDAR_VALID bit in SIER.
*/
static inline void perf_get_data_addr(struct pt_regs *regs, u64 *addrp)
{
unsigned long mmcra = regs->dsisr;
bool sdar_valid;
if (ppmu->flags & PPMU_HAS_SIER)
sdar_valid = regs->dar & SIER_SDAR_VALID;
else {
unsigned long sdsync;
if (ppmu->flags & PPMU_SIAR_VALID)
sdsync = POWER7P_MMCRA_SDAR_VALID;
else if (ppmu->flags & PPMU_ALT_SIPR)
sdsync = POWER6_MMCRA_SDSYNC;
else
sdsync = MMCRA_SDSYNC;
sdar_valid = mmcra & sdsync;
}
if (!(mmcra & MMCRA_SAMPLE_ENABLE) || sdar_valid)
*addrp = mfspr(SPRN_SDAR);
}
static bool regs_sihv(struct pt_regs *regs)
{
unsigned long sihv = MMCRA_SIHV;
if (ppmu->flags & PPMU_HAS_SIER)
return !!(regs->dar & SIER_SIHV);
if (ppmu->flags & PPMU_ALT_SIPR)
sihv = POWER6_MMCRA_SIHV;
return !!(regs->dsisr & sihv);
}
static bool regs_sipr(struct pt_regs *regs)
{
unsigned long sipr = MMCRA_SIPR;
if (ppmu->flags & PPMU_HAS_SIER)
return !!(regs->dar & SIER_SIPR);
if (ppmu->flags & PPMU_ALT_SIPR)
sipr = POWER6_MMCRA_SIPR;
return !!(regs->dsisr & sipr);
}
static inline u32 perf_flags_from_msr(struct pt_regs *regs)
{
if (regs->msr & MSR_PR)
return PERF_RECORD_MISC_USER;
if ((regs->msr & MSR_HV) && freeze_events_kernel != MMCR0_FCHV)
return PERF_RECORD_MISC_HYPERVISOR;
return PERF_RECORD_MISC_KERNEL;
}
static inline u32 perf_get_misc_flags(struct pt_regs *regs)
{
bool use_siar = regs_use_siar(regs);
if (!use_siar)
return perf_flags_from_msr(regs);
/*
* If we don't have flags in MMCRA, rather than using
* the MSR, we intuit the flags from the address in
* SIAR which should give slightly more reliable
* results
*/
if (ppmu->flags & PPMU_NO_SIPR) {
unsigned long siar = mfspr(SPRN_SIAR);
if (siar >= PAGE_OFFSET)
return PERF_RECORD_MISC_KERNEL;
return PERF_RECORD_MISC_USER;
}
/* PR has priority over HV, so order below is important */
if (regs_sipr(regs))
return PERF_RECORD_MISC_USER;
if (regs_sihv(regs) && (freeze_events_kernel != MMCR0_FCHV))
return PERF_RECORD_MISC_HYPERVISOR;
return PERF_RECORD_MISC_KERNEL;
}
/*
* Overload regs->dsisr to store MMCRA so we only need to read it once
* on each interrupt.
* Overload regs->dar to store SIER if we have it.
* Overload regs->result to specify whether we should use the MSR (result
* is zero) or the SIAR (result is non zero).
*/
static inline void perf_read_regs(struct pt_regs *regs)
{
unsigned long mmcra = mfspr(SPRN_MMCRA);
int marked = mmcra & MMCRA_SAMPLE_ENABLE;
int use_siar;
regs->dsisr = mmcra;
if (ppmu->flags & PPMU_HAS_SIER)
regs->dar = mfspr(SPRN_SIER);
/*
* If this isn't a PMU exception (eg a software event) the SIAR is
* not valid. Use pt_regs.
*
* If it is a marked event use the SIAR.
*
* If the PMU doesn't update the SIAR for non marked events use
* pt_regs.
*
* If the PMU has HV/PR flags then check to see if they
* place the exception in userspace. If so, use pt_regs. In
* continuous sampling mode the SIAR and the PMU exception are
* not synchronised, so they may be many instructions apart.
* This can result in confusing backtraces. We still want
* hypervisor samples as well as samples in the kernel with
* interrupts off hence the userspace check.
*/
if (TRAP(regs) != 0xf00)
use_siar = 0;
else if (marked)
use_siar = 1;
else if ((ppmu->flags & PPMU_NO_CONT_SAMPLING))
use_siar = 0;
else if (!(ppmu->flags & PPMU_NO_SIPR) && regs_sipr(regs))
use_siar = 0;
else
use_siar = 1;
regs->result = use_siar;
}
/*
* If interrupts were soft-disabled when a PMU interrupt occurs, treat
* it as an NMI.
*/
static inline int perf_intr_is_nmi(struct pt_regs *regs)
{
return !regs->softe;
}
/*
* On processors like P7+ that have the SIAR-Valid bit, marked instructions
* must be sampled only if the SIAR-valid bit is set.
*
* For unmarked instructions and for processors that don't have the SIAR-Valid
* bit, assume that SIAR is valid.
*/
static inline int siar_valid(struct pt_regs *regs)
{
unsigned long mmcra = regs->dsisr;
int marked = mmcra & MMCRA_SAMPLE_ENABLE;
if (marked) {
if (ppmu->flags & PPMU_HAS_SIER)
return regs->dar & SIER_SIAR_VALID;
if (ppmu->flags & PPMU_SIAR_VALID)
return mmcra & POWER7P_MMCRA_SIAR_VALID;
}
return 1;
}
/* Reset all possible BHRB entries */
static void power_pmu_bhrb_reset(void)
{
asm volatile(PPC_CLRBHRB);
}
static void power_pmu_bhrb_enable(struct perf_event *event)
{
struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
if (!ppmu->bhrb_nr)
return;
/* Clear BHRB if we changed task context to avoid data leaks */
if (event->ctx->task && cpuhw->bhrb_context != event->ctx) {
power_pmu_bhrb_reset();
cpuhw->bhrb_context = event->ctx;
}
cpuhw->bhrb_users++;
}
static void power_pmu_bhrb_disable(struct perf_event *event)
{
struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
if (!ppmu->bhrb_nr)
return;
cpuhw->bhrb_users--;
WARN_ON_ONCE(cpuhw->bhrb_users < 0);
if (!cpuhw->disabled && !cpuhw->bhrb_users) {
/* BHRB cannot be turned off when other
* events are active on the PMU.
*/
/* avoid stale pointer */
cpuhw->bhrb_context = NULL;
}
}
/* Called from ctxsw to prevent one process's branch entries to
* mingle with the other process's entries during context switch.
*/
void power_pmu_flush_branch_stack(void)
{
if (ppmu->bhrb_nr)
power_pmu_bhrb_reset();
}
/* Calculate the to address for a branch */
static __u64 power_pmu_bhrb_to(u64 addr)
{
unsigned int instr;
int ret;
__u64 target;
if (is_kernel_addr(addr))
return branch_target((unsigned int *)addr);
/* Userspace: need copy instruction here then translate it */
pagefault_disable();
ret = __get_user_inatomic(instr, (unsigned int __user *)addr);
if (ret) {
pagefault_enable();
return 0;
}
pagefault_enable();
target = branch_target(&instr);
if ((!target) || (instr & BRANCH_ABSOLUTE))
return target;
/* Translate relative branch target from kernel to user address */
return target - (unsigned long)&instr + addr;
}
/* Processing BHRB entries */
void power_pmu_bhrb_read(struct cpu_hw_events *cpuhw)
{
u64 val;
u64 addr;
int r_index, u_index, pred;
r_index = 0;
u_index = 0;
while (r_index < ppmu->bhrb_nr) {
/* Assembly read function */
val = read_bhrb(r_index++);
if (!val)
/* Terminal marker: End of valid BHRB entries */
break;
else {
addr = val & BHRB_EA;
pred = val & BHRB_PREDICTION;
if (!addr)
/* invalid entry */
continue;
/* Branches are read most recent first (ie. mfbhrb 0 is
* the most recent branch).
* There are two types of valid entries:
* 1) a target entry which is the to address of a
* computed goto like a blr,bctr,btar. The next
* entry read from the bhrb will be branch
* corresponding to this target (ie. the actual
* blr/bctr/btar instruction).
* 2) a from address which is an actual branch. If a
* target entry proceeds this, then this is the
* matching branch for that target. If this is not
* following a target entry, then this is a branch
* where the target is given as an immediate field
* in the instruction (ie. an i or b form branch).
* In this case we need to read the instruction from
* memory to determine the target/to address.
*/
if (val & BHRB_TARGET) {
/* Target branches use two entries
* (ie. computed gotos/XL form)
*/
cpuhw->bhrb_entries[u_index].to = addr;
cpuhw->bhrb_entries[u_index].mispred = pred;
cpuhw->bhrb_entries[u_index].predicted = ~pred;
/* Get from address in next entry */
val = read_bhrb(r_index++);
addr = val & BHRB_EA;
if (val & BHRB_TARGET) {
/* Shouldn't have two targets in a
row.. Reset index and try again */
r_index--;
addr = 0;
}
cpuhw->bhrb_entries[u_index].from = addr;
} else {
/* Branches to immediate field
(ie I or B form) */
cpuhw->bhrb_entries[u_index].from = addr;
cpuhw->bhrb_entries[u_index].to =
power_pmu_bhrb_to(addr);
cpuhw->bhrb_entries[u_index].mispred = pred;
cpuhw->bhrb_entries[u_index].predicted = ~pred;
}
u_index++;
}
}
cpuhw->bhrb_stack.nr = u_index;
return;
}
static bool is_ebb_event(struct perf_event *event)
{
/*
* This could be a per-PMU callback, but we'd rather avoid the cost. We
* check that the PMU supports EBB, meaning those that don't can still
* use bit 63 of the event code for something else if they wish.
*/
return (ppmu->flags & PPMU_EBB) &&
((event->attr.config >> PERF_EVENT_CONFIG_EBB_SHIFT) & 1);
}
static int ebb_event_check(struct perf_event *event)
{
struct perf_event *leader = event->group_leader;
/* Event and group leader must agree on EBB */
if (is_ebb_event(leader) != is_ebb_event(event))
return -EINVAL;
if (is_ebb_event(event)) {
if (!(event->attach_state & PERF_ATTACH_TASK))
return -EINVAL;
if (!leader->attr.pinned || !leader->attr.exclusive)
return -EINVAL;
if (event->attr.freq ||
event->attr.inherit ||
event->attr.sample_type ||
event->attr.sample_period ||
event->attr.enable_on_exec)
return -EINVAL;
}
return 0;
}
static void ebb_event_add(struct perf_event *event)
{
if (!is_ebb_event(event) || current->thread.used_ebb)
return;
/*
* IFF this is the first time we've added an EBB event, set
* PMXE in the user MMCR0 so we can detect when it's cleared by
* userspace. We need this so that we can context switch while
* userspace is in the EBB handler (where PMXE is 0).
*/
current->thread.used_ebb = 1;
current->thread.mmcr0 |= MMCR0_PMXE;
}
static void ebb_switch_out(unsigned long mmcr0)
{
if (!(mmcr0 & MMCR0_EBE))
return;
current->thread.siar = mfspr(SPRN_SIAR);
current->thread.sier = mfspr(SPRN_SIER);
current->thread.sdar = mfspr(SPRN_SDAR);
current->thread.mmcr0 = mmcr0 & MMCR0_USER_MASK;
current->thread.mmcr2 = mfspr(SPRN_MMCR2) & MMCR2_USER_MASK;
}
static unsigned long ebb_switch_in(bool ebb, unsigned long mmcr0)
{
if (!ebb)
goto out;
/* Enable EBB and read/write to all 6 PMCs and BHRB for userspace */
mmcr0 |= MMCR0_EBE | MMCR0_BHRBA | MMCR0_PMCC_U6;
/*
* Add any bits from the user MMCR0, FC or PMAO. This is compatible
* with pmao_restore_workaround() because we may add PMAO but we never
* clear it here.
*/
mmcr0 |= current->thread.mmcr0;
/*
* Be careful not to set PMXE if userspace had it cleared. This is also
* compatible with pmao_restore_workaround() because it has already
* cleared PMXE and we leave PMAO alone.
*/
if (!(current->thread.mmcr0 & MMCR0_PMXE))
mmcr0 &= ~MMCR0_PMXE;
mtspr(SPRN_SIAR, current->thread.siar);
mtspr(SPRN_SIER, current->thread.sier);
mtspr(SPRN_SDAR, current->thread.sdar);
mtspr(SPRN_MMCR2, current->thread.mmcr2);
out:
return mmcr0;
}
static void pmao_restore_workaround(bool ebb)
{
unsigned pmcs[6];
if (!cpu_has_feature(CPU_FTR_PMAO_BUG))
return;
/*
* On POWER8E there is a hardware defect which affects the PMU context
* switch logic, ie. power_pmu_disable/enable().
*
* When a counter overflows PMXE is cleared and FC/PMAO is set in MMCR0
* by the hardware. Sometime later the actual PMU exception is
* delivered.
*
* If we context switch, or simply disable/enable, the PMU prior to the
* exception arriving, the exception will be lost when we clear PMAO.
*
* When we reenable the PMU, we will write the saved MMCR0 with PMAO
* set, and this _should_ generate an exception. However because of the
* defect no exception is generated when we write PMAO, and we get
* stuck with no counters counting but no exception delivered.
*
* The workaround is to detect this case and tweak the hardware to
* create another pending PMU exception.
*
* We do that by setting up PMC6 (cycles) for an imminent overflow and
* enabling the PMU. That causes a new exception to be generated in the
* chip, but we don't take it yet because we have interrupts hard
* disabled. We then write back the PMU state as we want it to be seen
* by the exception handler. When we reenable interrupts the exception
* handler will be called and see the correct state.
*
* The logic is the same for EBB, except that the exception is gated by
* us having interrupts hard disabled as well as the fact that we are
* not in userspace. The exception is finally delivered when we return
* to userspace.
*/
/* Only if PMAO is set and PMAO_SYNC is clear */
if ((current->thread.mmcr0 & (MMCR0_PMAO | MMCR0_PMAO_SYNC)) != MMCR0_PMAO)
return;
/* If we're doing EBB, only if BESCR[GE] is set */
if (ebb && !(current->thread.bescr & BESCR_GE))
return;
/*
* We are already soft-disabled in power_pmu_enable(). We need to hard
* enable to actually prevent the PMU exception from firing.
*/
hard_irq_disable();
/*
* This is a bit gross, but we know we're on POWER8E and have 6 PMCs.
* Using read/write_pmc() in a for loop adds 12 function calls and
* almost doubles our code size.
*/
pmcs[0] = mfspr(SPRN_PMC1);
pmcs[1] = mfspr(SPRN_PMC2);
pmcs[2] = mfspr(SPRN_PMC3);
pmcs[3] = mfspr(SPRN_PMC4);
pmcs[4] = mfspr(SPRN_PMC5);
pmcs[5] = mfspr(SPRN_PMC6);
/* Ensure all freeze bits are unset */
mtspr(SPRN_MMCR2, 0);
/* Set up PMC6 to overflow in one cycle */
mtspr(SPRN_PMC6, 0x7FFFFFFE);
/* Enable exceptions and unfreeze PMC6 */
mtspr(SPRN_MMCR0, MMCR0_PMXE | MMCR0_PMCjCE | MMCR0_PMAO);
/* Now we need to refreeze and restore the PMCs */
mtspr(SPRN_MMCR0, MMCR0_FC | MMCR0_PMAO);
mtspr(SPRN_PMC1, pmcs[0]);
mtspr(SPRN_PMC2, pmcs[1]);
mtspr(SPRN_PMC3, pmcs[2]);
mtspr(SPRN_PMC4, pmcs[3]);
mtspr(SPRN_PMC5, pmcs[4]);
mtspr(SPRN_PMC6, pmcs[5]);
}
#endif /* CONFIG_PPC64 */
static void perf_event_interrupt(struct pt_regs *regs);
/*
* Read one performance monitor counter (PMC).
*/
static unsigned long read_pmc(int idx)
{
unsigned long val;
switch (idx) {
case 1:
val = mfspr(SPRN_PMC1);
break;
case 2:
val = mfspr(SPRN_PMC2);
break;
case 3:
val = mfspr(SPRN_PMC3);
break;
case 4:
val = mfspr(SPRN_PMC4);
break;
case 5:
val = mfspr(SPRN_PMC5);
break;
case 6:
val = mfspr(SPRN_PMC6);
break;
#ifdef CONFIG_PPC64
case 7:
val = mfspr(SPRN_PMC7);
break;
case 8:
val = mfspr(SPRN_PMC8);
break;
#endif /* CONFIG_PPC64 */
default:
printk(KERN_ERR "oops trying to read PMC%d\n", idx);
val = 0;
}
return val;
}
/*
* Write one PMC.
*/
static void write_pmc(int idx, unsigned long val)
{
switch (idx) {
case 1:
mtspr(SPRN_PMC1, val);
break;
case 2:
mtspr(SPRN_PMC2, val);
break;
case 3:
mtspr(SPRN_PMC3, val);
break;
case 4:
mtspr(SPRN_PMC4, val);
break;
case 5:
mtspr(SPRN_PMC5, val);
break;
case 6:
mtspr(SPRN_PMC6, val);
break;
#ifdef CONFIG_PPC64
case 7:
mtspr(SPRN_PMC7, val);
break;
case 8:
mtspr(SPRN_PMC8, val);
break;
#endif /* CONFIG_PPC64 */
default:
printk(KERN_ERR "oops trying to write PMC%d\n", idx);
}
}
/* Called from sysrq_handle_showregs() */
void perf_event_print_debug(void)
{
unsigned long sdar, sier, flags;
u32 pmcs[MAX_HWEVENTS];
int i;
if (!ppmu->n_counter)
return;
local_irq_save(flags);
pr_info("CPU: %d PMU registers, ppmu = %s n_counters = %d",
smp_processor_id(), ppmu->name, ppmu->n_counter);
for (i = 0; i < ppmu->n_counter; i++)
pmcs[i] = read_pmc(i + 1);
for (; i < MAX_HWEVENTS; i++)
pmcs[i] = 0xdeadbeef;
pr_info("PMC1: %08x PMC2: %08x PMC3: %08x PMC4: %08x\n",
pmcs[0], pmcs[1], pmcs[2], pmcs[3]);
if (ppmu->n_counter > 4)
pr_info("PMC5: %08x PMC6: %08x PMC7: %08x PMC8: %08x\n",
pmcs[4], pmcs[5], pmcs[6], pmcs[7]);
pr_info("MMCR0: %016lx MMCR1: %016lx MMCRA: %016lx\n",
mfspr(SPRN_MMCR0), mfspr(SPRN_MMCR1), mfspr(SPRN_MMCRA));
sdar = sier = 0;
#ifdef CONFIG_PPC64
sdar = mfspr(SPRN_SDAR);
if (ppmu->flags & PPMU_HAS_SIER)
sier = mfspr(SPRN_SIER);
if (ppmu->flags & PPMU_EBB) {
pr_info("MMCR2: %016lx EBBHR: %016lx\n",
mfspr(SPRN_MMCR2), mfspr(SPRN_EBBHR));
pr_info("EBBRR: %016lx BESCR: %016lx\n",
mfspr(SPRN_EBBRR), mfspr(SPRN_BESCR));
}
#endif
pr_info("SIAR: %016lx SDAR: %016lx SIER: %016lx\n",
mfspr(SPRN_SIAR), sdar, sier);
local_irq_restore(flags);
}
/*
* Check if a set of events can all go on the PMU at once.
* If they can't, this will look at alternative codes for the events
* and see if any combination of alternative codes is feasible.
* The feasible set is returned in event_id[].
*/
static int power_check_constraints(struct cpu_hw_events *cpuhw,
u64 event_id[], unsigned int cflags[],
int n_ev)
{
unsigned long mask, value, nv;
unsigned long smasks[MAX_HWEVENTS], svalues[MAX_HWEVENTS];
int n_alt[MAX_HWEVENTS], choice[MAX_HWEVENTS];
int i, j;
unsigned long addf = ppmu->add_fields;
unsigned long tadd = ppmu->test_adder;
if (n_ev > ppmu->n_counter)
return -1;
/* First see if the events will go on as-is */
for (i = 0; i < n_ev; ++i) {
if ((cflags[i] & PPMU_LIMITED_PMC_REQD)
&& !ppmu->limited_pmc_event(event_id[i])) {
ppmu->get_alternatives(event_id[i], cflags[i],
cpuhw->alternatives[i]);
event_id[i] = cpuhw->alternatives[i][0];
}
if (ppmu->get_constraint(event_id[i], &cpuhw->amasks[i][0],
&cpuhw->avalues[i][0]))
return -1;
}
value = mask = 0;
for (i = 0; i < n_ev; ++i) {
nv = (value | cpuhw->avalues[i][0]) +
(value & cpuhw->avalues[i][0] & addf);
if ((((nv + tadd) ^ value) & mask) != 0 ||
(((nv + tadd) ^ cpuhw->avalues[i][0]) &
cpuhw->amasks[i][0]) != 0)
break;
value = nv;
mask |= cpuhw->amasks[i][0];
}
if (i == n_ev)
return 0; /* all OK */
/* doesn't work, gather alternatives... */
if (!ppmu->get_alternatives)
return -1;
for (i = 0; i < n_ev; ++i) {
choice[i] = 0;
n_alt[i] = ppmu->get_alternatives(event_id[i], cflags[i],
cpuhw->alternatives[i]);
for (j = 1; j < n_alt[i]; ++j)
ppmu->get_constraint(cpuhw->alternatives[i][j],
&cpuhw->amasks[i][j],
&cpuhw->avalues[i][j]);
}
/* enumerate all possibilities and see if any will work */
i = 0;
j = -1;
value = mask = nv = 0;
while (i < n_ev) {
if (j >= 0) {
/* we're backtracking, restore context */
value = svalues[i];
mask = smasks[i];
j = choice[i];
}
/*
* See if any alternative k for event_id i,
* where k > j, will satisfy the constraints.
*/
while (++j < n_alt[i]) {
nv = (value | cpuhw->avalues[i][j]) +
(value & cpuhw->avalues[i][j] & addf);
if ((((nv + tadd) ^ value) & mask) == 0 &&
(((nv + tadd) ^ cpuhw->avalues[i][j])
& cpuhw->amasks[i][j]) == 0)
break;
}
if (j >= n_alt[i]) {
/*
* No feasible alternative, backtrack
* to event_id i-1 and continue enumerating its
* alternatives from where we got up to.
*/
if (--i < 0)
return -1;
} else {
/*
* Found a feasible alternative for event_id i,
* remember where we got up to with this event_id,
* go on to the next event_id, and start with
* the first alternative for it.
*/
choice[i] = j;
svalues[i] = value;
smasks[i] = mask;
value = nv;
mask |= cpuhw->amasks[i][j];
++i;
j = -1;
}
}
/* OK, we have a feasible combination, tell the caller the solution */
for (i = 0; i < n_ev; ++i)
event_id[i] = cpuhw->alternatives[i][choice[i]];
return 0;
}
/*
* Check if newly-added events have consistent settings for
* exclude_{user,kernel,hv} with each other and any previously
* added events.
*/
static int check_excludes(struct perf_event **ctrs, unsigned int cflags[],
int n_prev, int n_new)
{
int eu = 0, ek = 0, eh = 0;
int i, n, first;
struct perf_event *event;
n = n_prev + n_new;
if (n <= 1)
return 0;
first = 1;
for (i = 0; i < n; ++i) {
if (cflags[i] & PPMU_LIMITED_PMC_OK) {
cflags[i] &= ~PPMU_LIMITED_PMC_REQD;
continue;
}
event = ctrs[i];
if (first) {
eu = event->attr.exclude_user;
ek = event->attr.exclude_kernel;
eh = event->attr.exclude_hv;
first = 0;
} else if (event->attr.exclude_user != eu ||
event->attr.exclude_kernel != ek ||
event->attr.exclude_hv != eh) {
return -EAGAIN;
}
}
if (eu || ek || eh)
for (i = 0; i < n; ++i)
if (cflags[i] & PPMU_LIMITED_PMC_OK)
cflags[i] |= PPMU_LIMITED_PMC_REQD;
return 0;
}
static u64 check_and_compute_delta(u64 prev, u64 val)
{
u64 delta = (val - prev) & 0xfffffffful;
/*
* POWER7 can roll back counter values, if the new value is smaller
* than the previous value it will cause the delta and the counter to
* have bogus values unless we rolled a counter over. If a coutner is
* rolled back, it will be smaller, but within 256, which is the maximum
* number of events to rollback at once. If we dectect a rollback
* return 0. This can lead to a small lack of precision in the
* counters.
*/
if (prev > val && (prev - val) < 256)
delta = 0;
return delta;
}
static void power_pmu_read(struct perf_event *event)
{
s64 val, delta, prev;
if (event->hw.state & PERF_HES_STOPPED)
return;
if (!event->hw.idx)
return;
if (is_ebb_event(event)) {
val = read_pmc(event->hw.idx);
local64_set(&event->hw.prev_count, val);
return;
}
/*
* Performance monitor interrupts come even when interrupts
* are soft-disabled, as long as interrupts are hard-enabled.
* Therefore we treat them like NMIs.
*/
do {
prev = local64_read(&event->hw.prev_count);
barrier();
val = read_pmc(event->hw.idx);
delta = check_and_compute_delta(prev, val);
if (!delta)
return;
} while (local64_cmpxchg(&event->hw.prev_count, prev, val) != prev);
local64_add(delta, &event->count);
local64_sub(delta, &event->hw.period_left);
}
/*
* On some machines, PMC5 and PMC6 can't be written, don't respect
* the freeze conditions, and don't generate interrupts. This tells
* us if `event' is using such a PMC.
*/
static int is_limited_pmc(int pmcnum)
{
return (ppmu->flags & PPMU_LIMITED_PMC5_6)
&& (pmcnum == 5 || pmcnum == 6);
}
static void freeze_limited_counters(struct cpu_hw_events *cpuhw,
unsigned long pmc5, unsigned long pmc6)
{
struct perf_event *event;
u64 val, prev, delta;
int i;
for (i = 0; i < cpuhw->n_limited; ++i) {
event = cpuhw->limited_counter[i];
if (!event->hw.idx)
continue;
val = (event->hw.idx == 5) ? pmc5 : pmc6;
prev = local64_read(&event->hw.prev_count);
event->hw.idx = 0;
delta = check_and_compute_delta(prev, val);
if (delta)
local64_add(delta, &event->count);
}
}
static void thaw_limited_counters(struct cpu_hw_events *cpuhw,
unsigned long pmc5, unsigned long pmc6)
{
struct perf_event *event;
u64 val, prev;
int i;
for (i = 0; i < cpuhw->n_limited; ++i) {
event = cpuhw->limited_counter[i];
event->hw.idx = cpuhw->limited_hwidx[i];
val = (event->hw.idx == 5) ? pmc5 : pmc6;
prev = local64_read(&event->hw.prev_count);
if (check_and_compute_delta(prev, val))
local64_set(&event->hw.prev_count, val);
perf_event_update_userpage(event);
}
}
/*
* Since limited events don't respect the freeze conditions, we
* have to read them immediately after freezing or unfreezing the
* other events. We try to keep the values from the limited
* events as consistent as possible by keeping the delay (in
* cycles and instructions) between freezing/unfreezing and reading
* the limited events as small and consistent as possible.
* Therefore, if any limited events are in use, we read them
* both, and always in the same order, to minimize variability,
* and do it inside the same asm that writes MMCR0.
*/
static void write_mmcr0(struct cpu_hw_events *cpuhw, unsigned long mmcr0)
{
unsigned long pmc5, pmc6;
if (!cpuhw->n_limited) {
mtspr(SPRN_MMCR0, mmcr0);
return;
}
/*
* Write MMCR0, then read PMC5 and PMC6 immediately.
* To ensure we don't get a performance monitor interrupt
* between writing MMCR0 and freezing/thawing the limited
* events, we first write MMCR0 with the event overflow
* interrupt enable bits turned off.
*/
asm volatile("mtspr %3,%2; mfspr %0,%4; mfspr %1,%5"
: "=&r" (pmc5), "=&r" (pmc6)
: "r" (mmcr0 & ~(MMCR0_PMC1CE | MMCR0_PMCjCE)),
"i" (SPRN_MMCR0),
"i" (SPRN_PMC5), "i" (SPRN_PMC6));
if (mmcr0 & MMCR0_FC)
freeze_limited_counters(cpuhw, pmc5, pmc6);
else
thaw_limited_counters(cpuhw, pmc5, pmc6);
/*
* Write the full MMCR0 including the event overflow interrupt
* enable bits, if necessary.
*/
if (mmcr0 & (MMCR0_PMC1CE | MMCR0_PMCjCE))
mtspr(SPRN_MMCR0, mmcr0);
}
/*
* Disable all events to prevent PMU interrupts and to allow
* events to be added or removed.
*/
static void power_pmu_disable(struct pmu *pmu)
{
struct cpu_hw_events *cpuhw;
unsigned long flags, mmcr0, val;
if (!ppmu)
return;
local_irq_save(flags);
cpuhw = &__get_cpu_var(cpu_hw_events);
if (!cpuhw->disabled) {
/*
* Check if we ever enabled the PMU on this cpu.
*/
if (!cpuhw->pmcs_enabled) {
ppc_enable_pmcs();
cpuhw->pmcs_enabled = 1;
}
/*
* Set the 'freeze counters' bit, clear EBE/BHRBA/PMCC/PMAO/FC56
*/
val = mmcr0 = mfspr(SPRN_MMCR0);
val |= MMCR0_FC;
val &= ~(MMCR0_EBE | MMCR0_BHRBA | MMCR0_PMCC | MMCR0_PMAO |
MMCR0_FC56);
/*
* The barrier is to make sure the mtspr has been
* executed and the PMU has frozen the events etc.
* before we return.
*/
write_mmcr0(cpuhw, val);
mb();
/*
* Disable instruction sampling if it was enabled
*/
if (cpuhw->mmcr[2] & MMCRA_SAMPLE_ENABLE) {
mtspr(SPRN_MMCRA,
cpuhw->mmcr[2] & ~MMCRA_SAMPLE_ENABLE);
mb();
}
cpuhw->disabled = 1;
cpuhw->n_added = 0;
ebb_switch_out(mmcr0);
}
local_irq_restore(flags);
}
/*
* Re-enable all events if disable == 0.
* If we were previously disabled and events were added, then
* put the new config on the PMU.
*/
static void power_pmu_enable(struct pmu *pmu)
{
struct perf_event *event;
struct cpu_hw_events *cpuhw;
unsigned long flags;
long i;
unsigned long val, mmcr0;
s64 left;
unsigned int hwc_index[MAX_HWEVENTS];
int n_lim;
int idx;
bool ebb;
if (!ppmu)
return;
local_irq_save(flags);
cpuhw = &__get_cpu_var(cpu_hw_events);
if (!cpuhw->disabled)
goto out;
if (cpuhw->n_events == 0) {
ppc_set_pmu_inuse(0);
goto out;
}
cpuhw->disabled = 0;
/*
* EBB requires an exclusive group and all events must have the EBB
* flag set, or not set, so we can just check a single event. Also we
* know we have at least one event.
*/
ebb = is_ebb_event(cpuhw->event[0]);
/*
* If we didn't change anything, or only removed events,
* no need to recalculate MMCR* settings and reset the PMCs.
* Just reenable the PMU with the current MMCR* settings
* (possibly updated for removal of events).
*/
if (!cpuhw->n_added) {
mtspr(SPRN_MMCRA, cpuhw->mmcr[2] & ~MMCRA_SAMPLE_ENABLE);
mtspr(SPRN_MMCR1, cpuhw->mmcr[1]);
goto out_enable;
}
/*
* Compute MMCR* values for the new set of events
*/
if (ppmu->compute_mmcr(cpuhw->events, cpuhw->n_events, hwc_index,
cpuhw->mmcr)) {
/* shouldn't ever get here */
printk(KERN_ERR "oops compute_mmcr failed\n");
goto out;
}
/*
* Add in MMCR0 freeze bits corresponding to the
* attr.exclude_* bits for the first event.
* We have already checked that all events have the
* same values for these bits as the first event.
*/
event = cpuhw->event[0];
if (event->attr.exclude_user)
cpuhw->mmcr[0] |= MMCR0_FCP;
if (event->attr.exclude_kernel)
cpuhw->mmcr[0] |= freeze_events_kernel;
if (event->attr.exclude_hv)
cpuhw->mmcr[0] |= MMCR0_FCHV;
/*
* Write the new configuration to MMCR* with the freeze
* bit set and set the hardware events to their initial values.
* Then unfreeze the events.
*/
ppc_set_pmu_inuse(1);
mtspr(SPRN_MMCRA, cpuhw->mmcr[2] & ~MMCRA_SAMPLE_ENABLE);
mtspr(SPRN_MMCR1, cpuhw->mmcr[1]);
mtspr(SPRN_MMCR0, (cpuhw->mmcr[0] & ~(MMCR0_PMC1CE | MMCR0_PMCjCE))
| MMCR0_FC);
/*
* Read off any pre-existing events that need to move
* to another PMC.
*/
for (i = 0; i < cpuhw->n_events; ++i) {
event = cpuhw->event[i];
if (event->hw.idx && event->hw.idx != hwc_index[i] + 1) {
power_pmu_read(event);
write_pmc(event->hw.idx, 0);
event->hw.idx = 0;
}
}
/*
* Initialize the PMCs for all the new and moved events.
*/
cpuhw->n_limited = n_lim = 0;
for (i = 0; i < cpuhw->n_events; ++i) {
event = cpuhw->event[i];
if (event->hw.idx)
continue;
idx = hwc_index[i] + 1;
if (is_limited_pmc(idx)) {
cpuhw->limited_counter[n_lim] = event;
cpuhw->limited_hwidx[n_lim] = idx;
++n_lim;
continue;
}
if (ebb)
val = local64_read(&event->hw.prev_count);
else {
val = 0;
if (event->hw.sample_period) {
left = local64_read(&event->hw.period_left);
if (left < 0x80000000L)
val = 0x80000000L - left;
}
local64_set(&event->hw.prev_count, val);
}
event->hw.idx = idx;
if (event->hw.state & PERF_HES_STOPPED)
val = 0;
write_pmc(idx, val);
perf_event_update_userpage(event);
}
cpuhw->n_limited = n_lim;
cpuhw->mmcr[0] |= MMCR0_PMXE | MMCR0_FCECE;
out_enable:
pmao_restore_workaround(ebb);
mmcr0 = ebb_switch_in(ebb, cpuhw->mmcr[0]);
mb();
if (cpuhw->bhrb_users)
ppmu->config_bhrb(cpuhw->bhrb_filter);
write_mmcr0(cpuhw, mmcr0);
/*
* Enable instruction sampling if necessary
*/
if (cpuhw->mmcr[2] & MMCRA_SAMPLE_ENABLE) {
mb();
mtspr(SPRN_MMCRA, cpuhw->mmcr[2]);
}
out:
local_irq_restore(flags);
}
static int collect_events(struct perf_event *group, int max_count,
struct perf_event *ctrs[], u64 *events,
unsigned int *flags)
{
int n = 0;
struct perf_event *event;
if (!is_software_event(group)) {
if (n >= max_count)
return -1;
ctrs[n] = group;
flags[n] = group->hw.event_base;
events[n++] = group->hw.config;
}
list_for_each_entry(event, &group->sibling_list, group_entry) {
if (!is_software_event(event) &&
event->state != PERF_EVENT_STATE_OFF) {
if (n >= max_count)
return -1;
ctrs[n] = event;
flags[n] = event->hw.event_base;
events[n++] = event->hw.config;
}
}
return n;
}
/*
* Add a event to the PMU.
* If all events are not already frozen, then we disable and
* re-enable the PMU in order to get hw_perf_enable to do the
* actual work of reconfiguring the PMU.
*/
static int power_pmu_add(struct perf_event *event, int ef_flags)
{
struct cpu_hw_events *cpuhw;
unsigned long flags;
int n0;
int ret = -EAGAIN;
local_irq_save(flags);
perf_pmu_disable(event->pmu);
/*
* Add the event to the list (if there is room)
* and check whether the total set is still feasible.
*/
cpuhw = &__get_cpu_var(cpu_hw_events);
n0 = cpuhw->n_events;
if (n0 >= ppmu->n_counter)
goto out;
cpuhw->event[n0] = event;
cpuhw->events[n0] = event->hw.config;
cpuhw->flags[n0] = event->hw.event_base;
/*
* This event may have been disabled/stopped in record_and_restart()
* because we exceeded the ->event_limit. If re-starting the event,
* clear the ->hw.state (STOPPED and UPTODATE flags), so the user
* notification is re-enabled.
*/
if (!(ef_flags & PERF_EF_START))
event->hw.state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
else
event->hw.state = 0;
/*
* If group events scheduling transaction was started,
* skip the schedulability test here, it will be performed
* at commit time(->commit_txn) as a whole
*/
if (cpuhw->group_flag & PERF_EVENT_TXN)
goto nocheck;
if (check_excludes(cpuhw->event, cpuhw->flags, n0, 1))
goto out;
if (power_check_constraints(cpuhw, cpuhw->events, cpuhw->flags, n0 + 1))
goto out;
event->hw.config = cpuhw->events[n0];
nocheck:
ebb_event_add(event);
++cpuhw->n_events;
++cpuhw->n_added;
ret = 0;
out:
if (has_branch_stack(event)) {
power_pmu_bhrb_enable(event);
cpuhw->bhrb_filter = ppmu->bhrb_filter_map(
event->attr.branch_sample_type);
}
perf_pmu_enable(event->pmu);
local_irq_restore(flags);
return ret;
}
/*
* Remove a event from the PMU.
*/
static void power_pmu_del(struct perf_event *event, int ef_flags)
{
struct cpu_hw_events *cpuhw;
long i;
unsigned long flags;
local_irq_save(flags);
perf_pmu_disable(event->pmu);
power_pmu_read(event);
cpuhw = &__get_cpu_var(cpu_hw_events);
for (i = 0; i < cpuhw->n_events; ++i) {
if (event == cpuhw->event[i]) {
while (++i < cpuhw->n_events) {
cpuhw->event[i-1] = cpuhw->event[i];
cpuhw->events[i-1] = cpuhw->events[i];
cpuhw->flags[i-1] = cpuhw->flags[i];
}
--cpuhw->n_events;
ppmu->disable_pmc(event->hw.idx - 1, cpuhw->mmcr);
if (event->hw.idx) {
write_pmc(event->hw.idx, 0);
event->hw.idx = 0;
}
perf_event_update_userpage(event);
break;
}
}
for (i = 0; i < cpuhw->n_limited; ++i)
if (event == cpuhw->limited_counter[i])
break;
if (i < cpuhw->n_limited) {
while (++i < cpuhw->n_limited) {
cpuhw->limited_counter[i-1] = cpuhw->limited_counter[i];
cpuhw->limited_hwidx[i-1] = cpuhw->limited_hwidx[i];
}
--cpuhw->n_limited;
}
if (cpuhw->n_events == 0) {
/* disable exceptions if no events are running */
cpuhw->mmcr[0] &= ~(MMCR0_PMXE | MMCR0_FCECE);
}
if (has_branch_stack(event))
power_pmu_bhrb_disable(event);
perf_pmu_enable(event->pmu);
local_irq_restore(flags);
}
/*
* POWER-PMU does not support disabling individual counters, hence
* program their cycle counter to their max value and ignore the interrupts.
*/
static void power_pmu_start(struct perf_event *event, int ef_flags)
{
unsigned long flags;
s64 left;
unsigned long val;
if (!event->hw.idx || !event->hw.sample_period)
return;
if (!(event->hw.state & PERF_HES_STOPPED))
return;
if (ef_flags & PERF_EF_RELOAD)
WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE));
local_irq_save(flags);
perf_pmu_disable(event->pmu);
event->hw.state = 0;
left = local64_read(&event->hw.period_left);
val = 0;
if (left < 0x80000000L)
val = 0x80000000L - left;
write_pmc(event->hw.idx, val);
perf_event_update_userpage(event);
perf_pmu_enable(event->pmu);
local_irq_restore(flags);
}
static void power_pmu_stop(struct perf_event *event, int ef_flags)
{
unsigned long flags;
if (!event->hw.idx || !event->hw.sample_period)
return;
if (event->hw.state & PERF_HES_STOPPED)
return;
local_irq_save(flags);
perf_pmu_disable(event->pmu);
power_pmu_read(event);
event->hw.state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
write_pmc(event->hw.idx, 0);
perf_event_update_userpage(event);
perf_pmu_enable(event->pmu);
local_irq_restore(flags);
}
/*
* Start group events scheduling transaction
* Set the flag to make pmu::enable() not perform the
* schedulability test, it will be performed at commit time
*/
void power_pmu_start_txn(struct pmu *pmu)
{
struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
perf_pmu_disable(pmu);
cpuhw->group_flag |= PERF_EVENT_TXN;
cpuhw->n_txn_start = cpuhw->n_events;
}
/*
* Stop group events scheduling transaction
* Clear the flag and pmu::enable() will perform the
* schedulability test.
*/
void power_pmu_cancel_txn(struct pmu *pmu)
{
struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
cpuhw->group_flag &= ~PERF_EVENT_TXN;
perf_pmu_enable(pmu);
}
/*
* Commit group events scheduling transaction
* Perform the group schedulability test as a whole
* Return 0 if success
*/
int power_pmu_commit_txn(struct pmu *pmu)
{
struct cpu_hw_events *cpuhw;
long i, n;
if (!ppmu)
return -EAGAIN;
cpuhw = &__get_cpu_var(cpu_hw_events);
n = cpuhw->n_events;
if (check_excludes(cpuhw->event, cpuhw->flags, 0, n))
return -EAGAIN;
i = power_check_constraints(cpuhw, cpuhw->events, cpuhw->flags, n);
if (i < 0)
return -EAGAIN;
for (i = cpuhw->n_txn_start; i < n; ++i)
cpuhw->event[i]->hw.config = cpuhw->events[i];
cpuhw->group_flag &= ~PERF_EVENT_TXN;
perf_pmu_enable(pmu);
return 0;
}
/*
* Return 1 if we might be able to put event on a limited PMC,
* or 0 if not.
* A event can only go on a limited PMC if it counts something
* that a limited PMC can count, doesn't require interrupts, and
* doesn't exclude any processor mode.
*/
static int can_go_on_limited_pmc(struct perf_event *event, u64 ev,
unsigned int flags)
{
int n;
u64 alt[MAX_EVENT_ALTERNATIVES];
if (event->attr.exclude_user
|| event->attr.exclude_kernel
|| event->attr.exclude_hv
|| event->attr.sample_period)
return 0;
if (ppmu->limited_pmc_event(ev))
return 1;
/*
* The requested event_id isn't on a limited PMC already;
* see if any alternative code goes on a limited PMC.
*/
if (!ppmu->get_alternatives)
return 0;
flags |= PPMU_LIMITED_PMC_OK | PPMU_LIMITED_PMC_REQD;
n = ppmu->get_alternatives(ev, flags, alt);
return n > 0;
}
/*
* Find an alternative event_id that goes on a normal PMC, if possible,
* and return the event_id code, or 0 if there is no such alternative.
* (Note: event_id code 0 is "don't count" on all machines.)
*/
static u64 normal_pmc_alternative(u64 ev, unsigned long flags)
{
u64 alt[MAX_EVENT_ALTERNATIVES];
int n;
flags &= ~(PPMU_LIMITED_PMC_OK | PPMU_LIMITED_PMC_REQD);
n = ppmu->get_alternatives(ev, flags, alt);
if (!n)
return 0;
return alt[0];
}
/* Number of perf_events counting hardware events */
static atomic_t num_events;
/* Used to avoid races in calling reserve/release_pmc_hardware */
static DEFINE_MUTEX(pmc_reserve_mutex);
/*
* Release the PMU if this is the last perf_event.
*/
static void hw_perf_event_destroy(struct perf_event *event)
{
if (!atomic_add_unless(&num_events, -1, 1)) {
mutex_lock(&pmc_reserve_mutex);
if (atomic_dec_return(&num_events) == 0)
release_pmc_hardware();
mutex_unlock(&pmc_reserve_mutex);
}
}
/*
* Translate a generic cache event_id config to a raw event_id code.
*/
static int hw_perf_cache_event(u64 config, u64 *eventp)
{
unsigned long type, op, result;
int ev;
if (!ppmu->cache_events)
return -EINVAL;
/* unpack config */
type = config & 0xff;
op = (config >> 8) & 0xff;
result = (config >> 16) & 0xff;
if (type >= PERF_COUNT_HW_CACHE_MAX ||
op >= PERF_COUNT_HW_CACHE_OP_MAX ||
result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
return -EINVAL;
ev = (*ppmu->cache_events)[type][op][result];
if (ev == 0)
return -EOPNOTSUPP;
if (ev == -1)
return -EINVAL;
*eventp = ev;
return 0;
}
static int power_pmu_event_init(struct perf_event *event)
{
u64 ev;
unsigned long flags;
struct perf_event *ctrs[MAX_HWEVENTS];
u64 events[MAX_HWEVENTS];
unsigned int cflags[MAX_HWEVENTS];
int n;
int err;
struct cpu_hw_events *cpuhw;
if (!ppmu)
return -ENOENT;
if (has_branch_stack(event)) {
/* PMU has BHRB enabled */
if (!(ppmu->flags & PPMU_BHRB))
return -EOPNOTSUPP;
}
switch (event->attr.type) {
case PERF_TYPE_HARDWARE:
ev = event->attr.config;
if (ev >= ppmu->n_generic || ppmu->generic_events[ev] == 0)
return -EOPNOTSUPP;
ev = ppmu->generic_events[ev];
break;
case PERF_TYPE_HW_CACHE:
err = hw_perf_cache_event(event->attr.config, &ev);
if (err)
return err;
break;
case PERF_TYPE_RAW:
ev = event->attr.config;
break;
default:
return -ENOENT;
}
event->hw.config_base = ev;
event->hw.idx = 0;
/*
* If we are not running on a hypervisor, force the
* exclude_hv bit to 0 so that we don't care what
* the user set it to.
*/
if (!firmware_has_feature(FW_FEATURE_LPAR))
event->attr.exclude_hv = 0;
/*
* If this is a per-task event, then we can use
* PM_RUN_* events interchangeably with their non RUN_*
* equivalents, e.g. PM_RUN_CYC instead of PM_CYC.
* XXX we should check if the task is an idle task.
*/
flags = 0;
if (event->attach_state & PERF_ATTACH_TASK)
flags |= PPMU_ONLY_COUNT_RUN;
/*
* If this machine has limited events, check whether this
* event_id could go on a limited event.
*/
if (ppmu->flags & PPMU_LIMITED_PMC5_6) {
if (can_go_on_limited_pmc(event, ev, flags)) {
flags |= PPMU_LIMITED_PMC_OK;
} else if (ppmu->limited_pmc_event(ev)) {
/*
* The requested event_id is on a limited PMC,
* but we can't use a limited PMC; see if any
* alternative goes on a normal PMC.
*/
ev = normal_pmc_alternative(ev, flags);
if (!ev)
return -EINVAL;
}
}
/* Extra checks for EBB */
err = ebb_event_check(event);
if (err)
return err;
/*
* If this is in a group, check if it can go on with all the
* other hardware events in the group. We assume the event
* hasn't been linked into its leader's sibling list at this point.
*/
n = 0;
if (event->group_leader != event) {
n = collect_events(event->group_leader, ppmu->n_counter - 1,
ctrs, events, cflags);
if (n < 0)
return -EINVAL;
}
events[n] = ev;
ctrs[n] = event;
cflags[n] = flags;
if (check_excludes(ctrs, cflags, n, 1))
return -EINVAL;
cpuhw = &get_cpu_var(cpu_hw_events);
err = power_check_constraints(cpuhw, events, cflags, n + 1);
if (has_branch_stack(event)) {
cpuhw->bhrb_filter = ppmu->bhrb_filter_map(
event->attr.branch_sample_type);
if(cpuhw->bhrb_filter == -1)
return -EOPNOTSUPP;
}
put_cpu_var(cpu_hw_events);
if (err)
return -EINVAL;
event->hw.config = events[n];
event->hw.event_base = cflags[n];
event->hw.last_period = event->hw.sample_period;
local64_set(&event->hw.period_left, event->hw.last_period);
/*
* For EBB events we just context switch the PMC value, we don't do any
* of the sample_period logic. We use hw.prev_count for this.
*/
if (is_ebb_event(event))
local64_set(&event->hw.prev_count, 0);
/*
* See if we need to reserve the PMU.
* If no events are currently in use, then we have to take a
* mutex to ensure that we don't race with another task doing
* reserve_pmc_hardware or release_pmc_hardware.
*/
err = 0;
if (!atomic_inc_not_zero(&num_events)) {
mutex_lock(&pmc_reserve_mutex);
if (atomic_read(&num_events) == 0 &&
reserve_pmc_hardware(perf_event_interrupt))
err = -EBUSY;
else
atomic_inc(&num_events);
mutex_unlock(&pmc_reserve_mutex);
}
event->destroy = hw_perf_event_destroy;
return err;
}
static int power_pmu_event_idx(struct perf_event *event)
{
return event->hw.idx;
}
ssize_t power_events_sysfs_show(struct device *dev,
struct device_attribute *attr, char *page)
{
struct perf_pmu_events_attr *pmu_attr;
pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr);
return sprintf(page, "event=0x%02llx\n", pmu_attr->id);
}
struct pmu power_pmu = {
.pmu_enable = power_pmu_enable,
.pmu_disable = power_pmu_disable,
.event_init = power_pmu_event_init,
.add = power_pmu_add,
.del = power_pmu_del,
.start = power_pmu_start,
.stop = power_pmu_stop,
.read = power_pmu_read,
.start_txn = power_pmu_start_txn,
.cancel_txn = power_pmu_cancel_txn,
.commit_txn = power_pmu_commit_txn,
.event_idx = power_pmu_event_idx,
.flush_branch_stack = power_pmu_flush_branch_stack,
};
/*
* A counter has overflowed; update its count and record
* things if requested. Note that interrupts are hard-disabled
* here so there is no possibility of being interrupted.
*/
static void record_and_restart(struct perf_event *event, unsigned long val,
struct pt_regs *regs)
{
u64 period = event->hw.sample_period;
s64 prev, delta, left;
int record = 0;
if (event->hw.state & PERF_HES_STOPPED) {
write_pmc(event->hw.idx, 0);
return;
}
/* we don't have to worry about interrupts here */
prev = local64_read(&event->hw.prev_count);
delta = check_and_compute_delta(prev, val);
local64_add(delta, &event->count);
/*
* See if the total period for this event has expired,
* and update for the next period.
*/
val = 0;
left = local64_read(&event->hw.period_left) - delta;
if (delta == 0)
left++;
if (period) {
if (left <= 0) {
left += period;
if (left <= 0)
left = period;
record = siar_valid(regs);
event->hw.last_period = event->hw.sample_period;
}
if (left < 0x80000000LL)
val = 0x80000000LL - left;
}
write_pmc(event->hw.idx, val);
local64_set(&event->hw.prev_count, val);
local64_set(&event->hw.period_left, left);
perf_event_update_userpage(event);
/*
* Finally record data if requested.
*/
if (record) {
struct perf_sample_data data;
perf_sample_data_init(&data, ~0ULL, event->hw.last_period);
if (event->attr.sample_type & PERF_SAMPLE_ADDR)
perf_get_data_addr(regs, &data.addr);
if (event->attr.sample_type & PERF_SAMPLE_BRANCH_STACK) {
struct cpu_hw_events *cpuhw;
cpuhw = &__get_cpu_var(cpu_hw_events);
power_pmu_bhrb_read(cpuhw);
data.br_stack = &cpuhw->bhrb_stack;
}
if (perf_event_overflow(event, &data, regs))
power_pmu_stop(event, 0);
}
}
/*
* Called from generic code to get the misc flags (i.e. processor mode)
* for an event_id.
*/
unsigned long perf_misc_flags(struct pt_regs *regs)
{
u32 flags = perf_get_misc_flags(regs);
if (flags)
return flags;
return user_mode(regs) ? PERF_RECORD_MISC_USER :
PERF_RECORD_MISC_KERNEL;
}
/*
* Called from generic code to get the instruction pointer
* for an event_id.
*/
unsigned long perf_instruction_pointer(struct pt_regs *regs)
{
bool use_siar = regs_use_siar(regs);
if (use_siar && siar_valid(regs))
return mfspr(SPRN_SIAR) + perf_ip_adjust(regs);
else if (use_siar)
return 0; // no valid instruction pointer
else
return regs->nip;
}
static bool pmc_overflow_power7(unsigned long val)
{
/*
* Events on POWER7 can roll back if a speculative event doesn't
* eventually complete. Unfortunately in some rare cases they will
* raise a performance monitor exception. We need to catch this to
* ensure we reset the PMC. In all cases the PMC will be 256 or less
* cycles from overflow.
*
* We only do this if the first pass fails to find any overflowing
* PMCs because a user might set a period of less than 256 and we
* don't want to mistakenly reset them.
*/
if ((0x80000000 - val) <= 256)
return true;
return false;
}
static bool pmc_overflow(unsigned long val)
{
if ((int)val < 0)
return true;
return false;
}
/*
* Performance monitor interrupt stuff
*/
static void perf_event_interrupt(struct pt_regs *regs)
{
int i, j;
struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events);
struct perf_event *event;
unsigned long val[8];
int found, active;
int nmi;
if (cpuhw->n_limited)
freeze_limited_counters(cpuhw, mfspr(SPRN_PMC5),
mfspr(SPRN_PMC6));
perf_read_regs(regs);
nmi = perf_intr_is_nmi(regs);
if (nmi)
nmi_enter();
else
irq_enter();
/* Read all the PMCs since we'll need them a bunch of times */
for (i = 0; i < ppmu->n_counter; ++i)
val[i] = read_pmc(i + 1);
/* Try to find what caused the IRQ */
found = 0;
for (i = 0; i < ppmu->n_counter; ++i) {
if (!pmc_overflow(val[i]))
continue;
if (is_limited_pmc(i + 1))
continue; /* these won't generate IRQs */
/*
* We've found one that's overflowed. For active
* counters we need to log this. For inactive
* counters, we need to reset it anyway
*/
found = 1;
active = 0;
for (j = 0; j < cpuhw->n_events; ++j) {
event = cpuhw->event[j];
if (event->hw.idx == (i + 1)) {
active = 1;
record_and_restart(event, val[i], regs);
break;
}
}
if (!active)
/* reset non active counters that have overflowed */
write_pmc(i + 1, 0);
}
if (!found && pvr_version_is(PVR_POWER7)) {
/* check active counters for special buggy p7 overflow */
for (i = 0; i < cpuhw->n_events; ++i) {
event = cpuhw->event[i];
if (!event->hw.idx || is_limited_pmc(event->hw.idx))
continue;
if (pmc_overflow_power7(val[event->hw.idx - 1])) {
/* event has overflowed in a buggy way*/
found = 1;
record_and_restart(event,
val[event->hw.idx - 1],
regs);
}
}
}
if (!found && !nmi && printk_ratelimit())
printk(KERN_WARNING "Can't find PMC that caused IRQ\n");
/*
* Reset MMCR0 to its normal value. This will set PMXE and
* clear FC (freeze counters) and PMAO (perf mon alert occurred)
* and thus allow interrupts to occur again.
* XXX might want to use MSR.PM to keep the events frozen until
* we get back out of this interrupt.
*/
write_mmcr0(cpuhw, cpuhw->mmcr[0]);
if (nmi)
nmi_exit();
else
irq_exit();
}
static void power_pmu_setup(int cpu)
{
struct cpu_hw_events *cpuhw = &per_cpu(cpu_hw_events, cpu);
if (!ppmu)
return;
memset(cpuhw, 0, sizeof(*cpuhw));
cpuhw->mmcr[0] = MMCR0_FC;
}
static int
power_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
{
unsigned int cpu = (long)hcpu;
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_UP_PREPARE:
power_pmu_setup(cpu);
break;
default:
break;
}
return NOTIFY_OK;
}
int register_power_pmu(struct power_pmu *pmu)
{
if (ppmu)
return -EBUSY; /* something's already registered */
ppmu = pmu;
pr_info("%s performance monitor hardware support registered\n",
pmu->name);
power_pmu.attr_groups = ppmu->attr_groups;
#ifdef MSR_HV
/*
* Use FCHV to ignore kernel events if MSR.HV is set.
*/
if (mfmsr() & MSR_HV)
freeze_events_kernel = MMCR0_FCHV;
#endif /* CONFIG_PPC64 */
perf_pmu_register(&power_pmu, "cpu", PERF_TYPE_RAW);
perf_cpu_notifier(power_pmu_notifier);
return 0;
}
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