#include <linux/init.h>
#include <linux/slab.h>
#include <linux/debugfs.h>
+#include <linux/spinlock.h>
#include <asm/smp.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/firmware.h>
+#include <asm/lppaca.h>
#include "plpar_wrappers.h"
-/*
- * Layout of entries in the hypervisor's DTL buffer. Although we don't
- * actually access the internals of an entry (we only need to know the size),
- * we might as well define it here for reference.
- */
-struct dtl_entry {
- u8 dispatch_reason;
- u8 preempt_reason;
- u16 processor_id;
- u32 enqueue_to_dispatch_time;
- u32 ready_to_enqueue_time;
- u32 waiting_to_ready_time;
- u64 timebase;
- u64 fault_addr;
- u64 srr0;
- u64 srr1;
-};
-
struct dtl {
struct dtl_entry *buf;
struct dentry *file;
int cpu;
int buf_entries;
u64 last_idx;
+ spinlock_t lock;
};
static DEFINE_PER_CPU(struct dtl, cpu_dtl);
static int dtl_buf_entries = (16 * 85);
-static int dtl_enable(struct dtl *dtl)
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+struct dtl_ring {
+ u64 write_index;
+ struct dtl_entry *write_ptr;
+ struct dtl_entry *buf;
+ struct dtl_entry *buf_end;
+ u8 saved_dtl_mask;
+};
+
+static DEFINE_PER_CPU(struct dtl_ring, dtl_rings);
+
+static atomic_t dtl_count;
+
+/*
+ * The cpu accounting code controls the DTL ring buffer, and we get
+ * given entries as they are processed.
+ */
+static void consume_dtle(struct dtl_entry *dtle, u64 index)
{
- unsigned long addr;
- int ret, hwcpu;
+ struct dtl_ring *dtlr = &__get_cpu_var(dtl_rings);
+ struct dtl_entry *wp = dtlr->write_ptr;
+ struct lppaca *vpa = local_paca->lppaca_ptr;
- /* only allow one reader */
- if (dtl->buf)
- return -EBUSY;
+ if (!wp)
+ return;
- /* we need to store the original allocation size for use during read */
- dtl->buf_entries = dtl_buf_entries;
+ *wp = *dtle;
+ barrier();
- dtl->buf = kmalloc_node(dtl->buf_entries * sizeof(struct dtl_entry),
- GFP_KERNEL, cpu_to_node(dtl->cpu));
- if (!dtl->buf) {
- printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n",
- __func__, dtl->cpu);
- return -ENOMEM;
- }
+ /* check for hypervisor ring buffer overflow, ignore this entry if so */
+ if (index + N_DISPATCH_LOG < vpa->dtl_idx)
+ return;
+
+ ++wp;
+ if (wp == dtlr->buf_end)
+ wp = dtlr->buf;
+ dtlr->write_ptr = wp;
+
+ /* incrementing write_index makes the new entry visible */
+ smp_wmb();
+ ++dtlr->write_index;
+}
+
+static int dtl_start(struct dtl *dtl)
+{
+ struct dtl_ring *dtlr = &per_cpu(dtl_rings, dtl->cpu);
+
+ dtlr->buf = dtl->buf;
+ dtlr->buf_end = dtl->buf + dtl->buf_entries;
+ dtlr->write_index = 0;
+
+ /* setting write_ptr enables logging into our buffer */
+ smp_wmb();
+ dtlr->write_ptr = dtl->buf;
+
+ /* enable event logging */
+ dtlr->saved_dtl_mask = lppaca_of(dtl->cpu).dtl_enable_mask;
+ lppaca_of(dtl->cpu).dtl_enable_mask |= dtl_event_mask;
+
+ dtl_consumer = consume_dtle;
+ atomic_inc(&dtl_count);
+ return 0;
+}
+
+static void dtl_stop(struct dtl *dtl)
+{
+ struct dtl_ring *dtlr = &per_cpu(dtl_rings, dtl->cpu);
+
+ dtlr->write_ptr = NULL;
+ smp_wmb();
+
+ dtlr->buf = NULL;
+
+ /* restore dtl_enable_mask */
+ lppaca_of(dtl->cpu).dtl_enable_mask = dtlr->saved_dtl_mask;
+
+ if (atomic_dec_and_test(&dtl_count))
+ dtl_consumer = NULL;
+}
+
+static u64 dtl_current_index(struct dtl *dtl)
+{
+ return per_cpu(dtl_rings, dtl->cpu).write_index;
+}
+
+#else /* CONFIG_VIRT_CPU_ACCOUNTING */
+
+static int dtl_start(struct dtl *dtl)
+{
+ unsigned long addr;
+ int ret, hwcpu;
/* Register our dtl buffer with the hypervisor. The HV expects the
* buffer size to be passed in the second word of the buffer */
if (ret) {
printk(KERN_WARNING "%s: DTL registration for cpu %d (hw %d) "
"failed with %d\n", __func__, dtl->cpu, hwcpu, ret);
- kfree(dtl->buf);
return -EIO;
}
/* set our initial buffer indices */
- dtl->last_idx = lppaca[dtl->cpu].dtl_idx = 0;
+ lppaca_of(dtl->cpu).dtl_idx = 0;
/* ensure that our updates to the lppaca fields have occurred before
* we actually enable the logging */
smp_wmb();
/* enable event logging */
- lppaca[dtl->cpu].dtl_enable_mask = dtl_event_mask;
+ lppaca_of(dtl->cpu).dtl_enable_mask = dtl_event_mask;
return 0;
}
-static void dtl_disable(struct dtl *dtl)
+static void dtl_stop(struct dtl *dtl)
{
int hwcpu = get_hard_smp_processor_id(dtl->cpu);
- lppaca[dtl->cpu].dtl_enable_mask = 0x0;
+ lppaca_of(dtl->cpu).dtl_enable_mask = 0x0;
unregister_dtl(hwcpu, __pa(dtl->buf));
+}
+
+static u64 dtl_current_index(struct dtl *dtl)
+{
+ return lppaca_of(dtl->cpu).dtl_idx;
+}
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
+
+static int dtl_enable(struct dtl *dtl)
+{
+ long int n_entries;
+ long int rc;
+ struct dtl_entry *buf = NULL;
+ /* only allow one reader */
+ if (dtl->buf)
+ return -EBUSY;
+
+ n_entries = dtl_buf_entries;
+ buf = kmalloc_node(n_entries * sizeof(struct dtl_entry),
+ GFP_KERNEL, cpu_to_node(dtl->cpu));
+ if (!buf) {
+ printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n",
+ __func__, dtl->cpu);
+ return -ENOMEM;
+ }
+
+ spin_lock(&dtl->lock);
+ rc = -EBUSY;
+ if (!dtl->buf) {
+ /* store the original allocation size for use during read */
+ dtl->buf_entries = n_entries;
+ dtl->buf = buf;
+ dtl->last_idx = 0;
+ rc = dtl_start(dtl);
+ if (rc)
+ dtl->buf = NULL;
+ }
+ spin_unlock(&dtl->lock);
+
+ if (rc)
+ kfree(buf);
+ return rc;
+}
+
+static void dtl_disable(struct dtl *dtl)
+{
+ spin_lock(&dtl->lock);
+ dtl_stop(dtl);
kfree(dtl->buf);
dtl->buf = NULL;
dtl->buf_entries = 0;
+ spin_unlock(&dtl->lock);
}
/* file interface */
static ssize_t dtl_file_read(struct file *filp, char __user *buf, size_t len,
loff_t *pos)
{
- int rc, cur_idx, last_idx, n_read, n_req, read_size;
+ long int rc, n_read, n_req, read_size;
struct dtl *dtl;
+ u64 cur_idx, last_idx, i;
if ((len % sizeof(struct dtl_entry)) != 0)
return -EINVAL;
/* actual number of entries read */
n_read = 0;
- cur_idx = lppaca[dtl->cpu].dtl_idx;
+ spin_lock(&dtl->lock);
+
+ cur_idx = dtl_current_index(dtl);
last_idx = dtl->last_idx;
- if (cur_idx - last_idx > dtl->buf_entries) {
- pr_debug("%s: hv buffer overflow for cpu %d, samples lost\n",
- __func__, dtl->cpu);
- }
+ if (last_idx + dtl->buf_entries <= cur_idx)
+ last_idx = cur_idx - dtl->buf_entries + 1;
+
+ if (last_idx + n_req > cur_idx)
+ n_req = cur_idx - last_idx;
+
+ if (n_req > 0)
+ dtl->last_idx = last_idx + n_req;
+
+ spin_unlock(&dtl->lock);
+
+ if (n_req <= 0)
+ return 0;
- cur_idx %= dtl->buf_entries;
- last_idx %= dtl->buf_entries;
+ i = last_idx % dtl->buf_entries;
/* read the tail of the buffer if we've wrapped */
- if (last_idx > cur_idx) {
- read_size = min(n_req, dtl->buf_entries - last_idx);
+ if (i + n_req > dtl->buf_entries) {
+ read_size = dtl->buf_entries - i;
- rc = copy_to_user(buf, &dtl->buf[last_idx],
+ rc = copy_to_user(buf, &dtl->buf[i],
read_size * sizeof(struct dtl_entry));
if (rc)
return -EFAULT;
- last_idx = 0;
+ i = 0;
n_req -= read_size;
n_read += read_size;
buf += read_size * sizeof(struct dtl_entry);
}
/* .. and now the head */
- read_size = min(n_req, cur_idx - last_idx);
- rc = copy_to_user(buf, &dtl->buf[last_idx],
- read_size * sizeof(struct dtl_entry));
+ rc = copy_to_user(buf, &dtl->buf[i], n_req * sizeof(struct dtl_entry));
if (rc)
return -EFAULT;
- n_read += read_size;
- dtl->last_idx += n_read;
+ n_read += n_req;
return n_read * sizeof(struct dtl_entry);
}
/* set up the per-cpu log structures */
for_each_possible_cpu(i) {
struct dtl *dtl = &per_cpu(cpu_dtl, i);
+ spin_lock_init(&dtl->lock);
dtl->cpu = i;
rc = dtl_setup_file(dtl);
git.openpandora.org / pandora-kernel.git / blobdiff