+++ /dev/null
-/**
- * @file cpu_buffer.c
- *
- * @remark Copyright 2002-2009 OProfile authors
- * @remark Read the file COPYING
- *
- * @author John Levon <levon@movementarian.org>
- * @author Barry Kasindorf <barry.kasindorf@amd.com>
- * @author Robert Richter <robert.richter@amd.com>
- *
- * Each CPU has a local buffer that stores PC value/event
- * pairs. We also log context switches when we notice them.
- * Eventually each CPU's buffer is processed into the global
- * event buffer by sync_buffer().
- *
- * We use a local buffer for two reasons: an NMI or similar
- * interrupt cannot synchronise, and high sampling rates
- * would lead to catastrophic global synchronisation if
- * a global buffer was used.
- */
-
-#include <linux/sched.h>
-#include <linux/oprofile.h>
-#include <linux/errno.h>
-
-#include <asm/ptrace.h>
-
-#include "event_buffer.h"
-#include "cpu_buffer.h"
-#include "buffer_sync.h"
-#include "oprof.h"
-
-#define OP_BUFFER_FLAGS 0
-
-static struct trace_buffer *op_ring_buffer;
-DEFINE_PER_CPU(struct oprofile_cpu_buffer, op_cpu_buffer);
-
-static void wq_sync_buffer(struct work_struct *work);
-
-#define DEFAULT_TIMER_EXPIRE (HZ / 10)
-static int work_enabled;
-
-unsigned long oprofile_get_cpu_buffer_size(void)
-{
- return oprofile_cpu_buffer_size;
-}
-
-void oprofile_cpu_buffer_inc_smpl_lost(void)
-{
- struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);
-
- cpu_buf->sample_lost_overflow++;
-}
-
-void free_cpu_buffers(void)
-{
- if (op_ring_buffer)
- ring_buffer_free(op_ring_buffer);
- op_ring_buffer = NULL;
-}
-
-#define RB_EVENT_HDR_SIZE 4
-
-int alloc_cpu_buffers(void)
-{
- int i;
-
- unsigned long buffer_size = oprofile_cpu_buffer_size;
- unsigned long byte_size = buffer_size * (sizeof(struct op_sample) +
- RB_EVENT_HDR_SIZE);
-
- op_ring_buffer = ring_buffer_alloc(byte_size, OP_BUFFER_FLAGS);
- if (!op_ring_buffer)
- goto fail;
-
- for_each_possible_cpu(i) {
- struct oprofile_cpu_buffer *b = &per_cpu(op_cpu_buffer, i);
-
- b->last_task = NULL;
- b->last_is_kernel = -1;
- b->tracing = 0;
- b->buffer_size = buffer_size;
- b->sample_received = 0;
- b->sample_lost_overflow = 0;
- b->backtrace_aborted = 0;
- b->sample_invalid_eip = 0;
- b->cpu = i;
- INIT_DELAYED_WORK(&b->work, wq_sync_buffer);
- }
- return 0;
-
-fail:
- free_cpu_buffers();
- return -ENOMEM;
-}
-
-void start_cpu_work(void)
-{
- int i;
-
- work_enabled = 1;
-
- for_each_online_cpu(i) {
- struct oprofile_cpu_buffer *b = &per_cpu(op_cpu_buffer, i);
-
- /*
- * Spread the work by 1 jiffy per cpu so they dont all
- * fire at once.
- */
- schedule_delayed_work_on(i, &b->work, DEFAULT_TIMER_EXPIRE + i);
- }
-}
-
-void end_cpu_work(void)
-{
- work_enabled = 0;
-}
-
-void flush_cpu_work(void)
-{
- int i;
-
- for_each_online_cpu(i) {
- struct oprofile_cpu_buffer *b = &per_cpu(op_cpu_buffer, i);
-
- /* these works are per-cpu, no need for flush_sync */
- flush_delayed_work(&b->work);
- }
-}
-
-/*
- * This function prepares the cpu buffer to write a sample.
- *
- * Struct op_entry is used during operations on the ring buffer while
- * struct op_sample contains the data that is stored in the ring
- * buffer. Struct entry can be uninitialized. The function reserves a
- * data array that is specified by size. Use
- * op_cpu_buffer_write_commit() after preparing the sample. In case of
- * errors a null pointer is returned, otherwise the pointer to the
- * sample.
- *
- */
-struct op_sample
-*op_cpu_buffer_write_reserve(struct op_entry *entry, unsigned long size)
-{
- entry->event = ring_buffer_lock_reserve
- (op_ring_buffer, sizeof(struct op_sample) +
- size * sizeof(entry->sample->data[0]));
- if (!entry->event)
- return NULL;
- entry->sample = ring_buffer_event_data(entry->event);
- entry->size = size;
- entry->data = entry->sample->data;
-
- return entry->sample;
-}
-
-int op_cpu_buffer_write_commit(struct op_entry *entry)
-{
- return ring_buffer_unlock_commit(op_ring_buffer, entry->event);
-}
-
-struct op_sample *op_cpu_buffer_read_entry(struct op_entry *entry, int cpu)
-{
- struct ring_buffer_event *e;
- e = ring_buffer_consume(op_ring_buffer, cpu, NULL, NULL);
- if (!e)
- return NULL;
-
- entry->event = e;
- entry->sample = ring_buffer_event_data(e);
- entry->size = (ring_buffer_event_length(e) - sizeof(struct op_sample))
- / sizeof(entry->sample->data[0]);
- entry->data = entry->sample->data;
- return entry->sample;
-}
-
-unsigned long op_cpu_buffer_entries(int cpu)
-{
- return ring_buffer_entries_cpu(op_ring_buffer, cpu);
-}
-
-static int
-op_add_code(struct oprofile_cpu_buffer *cpu_buf, unsigned long backtrace,
- int is_kernel, struct task_struct *task)
-{
- struct op_entry entry;
- struct op_sample *sample;
- unsigned long flags;
- int size;
-
- flags = 0;
-
- if (backtrace)
- flags |= TRACE_BEGIN;
-
- /* notice a switch from user->kernel or vice versa */
- is_kernel = !!is_kernel;
- if (cpu_buf->last_is_kernel != is_kernel) {
- cpu_buf->last_is_kernel = is_kernel;
- flags |= KERNEL_CTX_SWITCH;
- if (is_kernel)
- flags |= IS_KERNEL;
- }
-
- /* notice a task switch */
- if (cpu_buf->last_task != task) {
- cpu_buf->last_task = task;
- flags |= USER_CTX_SWITCH;
- }
-
- if (!flags)
- /* nothing to do */
- return 0;
-
- if (flags & USER_CTX_SWITCH)
- size = 1;
- else
- size = 0;
-
- sample = op_cpu_buffer_write_reserve(&entry, size);
- if (!sample)
- return -ENOMEM;
-
- sample->eip = ESCAPE_CODE;
- sample->event = flags;
-
- if (size)
- op_cpu_buffer_add_data(&entry, (unsigned long)task);
-
- op_cpu_buffer_write_commit(&entry);
-
- return 0;
-}
-
-static inline int
-op_add_sample(struct oprofile_cpu_buffer *cpu_buf,
- unsigned long pc, unsigned long event)
-{
- struct op_entry entry;
- struct op_sample *sample;
-
- sample = op_cpu_buffer_write_reserve(&entry, 0);
- if (!sample)
- return -ENOMEM;
-
- sample->eip = pc;
- sample->event = event;
-
- return op_cpu_buffer_write_commit(&entry);
-}
-
-/*
- * This must be safe from any context.
- *
- * is_kernel is needed because on some architectures you cannot
- * tell if you are in kernel or user space simply by looking at
- * pc. We tag this in the buffer by generating kernel enter/exit
- * events whenever is_kernel changes
- */
-static int
-log_sample(struct oprofile_cpu_buffer *cpu_buf, unsigned long pc,
- unsigned long backtrace, int is_kernel, unsigned long event,
- struct task_struct *task)
-{
- struct task_struct *tsk = task ? task : current;
- cpu_buf->sample_received++;
-
- if (pc == ESCAPE_CODE) {
- cpu_buf->sample_invalid_eip++;
- return 0;
- }
-
- if (op_add_code(cpu_buf, backtrace, is_kernel, tsk))
- goto fail;
-
- if (op_add_sample(cpu_buf, pc, event))
- goto fail;
-
- return 1;
-
-fail:
- cpu_buf->sample_lost_overflow++;
- return 0;
-}
-
-static inline void oprofile_begin_trace(struct oprofile_cpu_buffer *cpu_buf)
-{
- cpu_buf->tracing = 1;
-}
-
-static inline void oprofile_end_trace(struct oprofile_cpu_buffer *cpu_buf)
-{
- cpu_buf->tracing = 0;
-}
-
-static inline void
-__oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs,
- unsigned long event, int is_kernel,
- struct task_struct *task)
-{
- struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);
- unsigned long backtrace = oprofile_backtrace_depth;
-
- /*
- * if log_sample() fail we can't backtrace since we lost the
- * source of this event
- */
- if (!log_sample(cpu_buf, pc, backtrace, is_kernel, event, task))
- /* failed */
- return;
-
- if (!backtrace)
- return;
-
- oprofile_begin_trace(cpu_buf);
- oprofile_ops.backtrace(regs, backtrace);
- oprofile_end_trace(cpu_buf);
-}
-
-void oprofile_add_ext_hw_sample(unsigned long pc, struct pt_regs * const regs,
- unsigned long event, int is_kernel,
- struct task_struct *task)
-{
- __oprofile_add_ext_sample(pc, regs, event, is_kernel, task);
-}
-
-void oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs,
- unsigned long event, int is_kernel)
-{
- __oprofile_add_ext_sample(pc, regs, event, is_kernel, NULL);
-}
-
-void oprofile_add_sample(struct pt_regs * const regs, unsigned long event)
-{
- int is_kernel;
- unsigned long pc;
-
- if (likely(regs)) {
- is_kernel = !user_mode(regs);
- pc = profile_pc(regs);
- } else {
- is_kernel = 0; /* This value will not be used */
- pc = ESCAPE_CODE; /* as this causes an early return. */
- }
-
- __oprofile_add_ext_sample(pc, regs, event, is_kernel, NULL);
-}
-
-/*
- * Add samples with data to the ring buffer.
- *
- * Use oprofile_add_data(&entry, val) to add data and
- * oprofile_write_commit(&entry) to commit the sample.
- */
-void
-oprofile_write_reserve(struct op_entry *entry, struct pt_regs * const regs,
- unsigned long pc, int code, int size)
-{
- struct op_sample *sample;
- int is_kernel = !user_mode(regs);
- struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);
-
- cpu_buf->sample_received++;
-
- /* no backtraces for samples with data */
- if (op_add_code(cpu_buf, 0, is_kernel, current))
- goto fail;
-
- sample = op_cpu_buffer_write_reserve(entry, size + 2);
- if (!sample)
- goto fail;
- sample->eip = ESCAPE_CODE;
- sample->event = 0; /* no flags */
-
- op_cpu_buffer_add_data(entry, code);
- op_cpu_buffer_add_data(entry, pc);
-
- return;
-
-fail:
- entry->event = NULL;
- cpu_buf->sample_lost_overflow++;
-}
-
-int oprofile_add_data(struct op_entry *entry, unsigned long val)
-{
- if (!entry->event)
- return 0;
- return op_cpu_buffer_add_data(entry, val);
-}
-
-int oprofile_add_data64(struct op_entry *entry, u64 val)
-{
- if (!entry->event)
- return 0;
- if (op_cpu_buffer_get_size(entry) < 2)
- /*
- * the function returns 0 to indicate a too small
- * buffer, even if there is some space left
- */
- return 0;
- if (!op_cpu_buffer_add_data(entry, (u32)val))
- return 0;
- return op_cpu_buffer_add_data(entry, (u32)(val >> 32));
-}
-
-int oprofile_write_commit(struct op_entry *entry)
-{
- if (!entry->event)
- return -EINVAL;
- return op_cpu_buffer_write_commit(entry);
-}
-
-void oprofile_add_pc(unsigned long pc, int is_kernel, unsigned long event)
-{
- struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);
- log_sample(cpu_buf, pc, 0, is_kernel, event, NULL);
-}
-
-void oprofile_add_trace(unsigned long pc)
-{
- struct oprofile_cpu_buffer *cpu_buf = this_cpu_ptr(&op_cpu_buffer);
-
- if (!cpu_buf->tracing)
- return;
-
- /*
- * broken frame can give an eip with the same value as an
- * escape code, abort the trace if we get it
- */
- if (pc == ESCAPE_CODE)
- goto fail;
-
- if (op_add_sample(cpu_buf, pc, 0))
- goto fail;
-
- return;
-fail:
- cpu_buf->tracing = 0;
- cpu_buf->backtrace_aborted++;
- return;
-}
-
-/*
- * This serves to avoid cpu buffer overflow, and makes sure
- * the task mortuary progresses
- *
- * By using schedule_delayed_work_on and then schedule_delayed_work
- * we guarantee this will stay on the correct cpu
- */
-static void wq_sync_buffer(struct work_struct *work)
-{
- struct oprofile_cpu_buffer *b =
- container_of(work, struct oprofile_cpu_buffer, work.work);
- if (b->cpu != smp_processor_id() && !cpu_online(b->cpu)) {
- cancel_delayed_work(&b->work);
- return;
- }
- sync_buffer(b->cpu);
-
- /* don't re-add the work if we're shutting down */
- if (work_enabled)
- schedule_delayed_work(&b->work, DEFAULT_TIMER_EXPIRE);
-}
projects / linux-2.6-microblaze.git / blobdiff