// SPDX-License-Identifier: GPL-2.0
|
/*
|
* Performance events ring-buffer code:
|
*
|
* Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
|
* Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
|
* Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
|
* Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
|
*/
|
|
#include <linux/perf_event.h>
|
#include <linux/vmalloc.h>
|
#include <linux/slab.h>
|
#include <linux/circ_buf.h>
|
#include <linux/poll.h>
|
#include <linux/nospec.h>
|
|
#include "internal.h"
|
|
static void perf_output_wakeup(struct perf_output_handle *handle)
|
{
|
atomic_set(&handle->rb->poll, EPOLLIN);
|
|
handle->event->pending_wakeup = 1;
|
irq_work_queue(&handle->event->pending);
|
}
|
|
/*
|
* We need to ensure a later event_id doesn't publish a head when a former
|
* event isn't done writing. However since we need to deal with NMIs we
|
* cannot fully serialize things.
|
*
|
* We only publish the head (and generate a wakeup) when the outer-most
|
* event completes.
|
*/
|
static void perf_output_get_handle(struct perf_output_handle *handle)
|
{
|
struct perf_buffer *rb = handle->rb;
|
|
preempt_disable();
|
|
/*
|
* Avoid an explicit LOAD/STORE such that architectures with memops
|
* can use them.
|
*/
|
(*(volatile unsigned int *)&rb->nest)++;
|
handle->wakeup = local_read(&rb->wakeup);
|
}
|
|
static void perf_output_put_handle(struct perf_output_handle *handle)
|
{
|
struct perf_buffer *rb = handle->rb;
|
unsigned long head;
|
unsigned int nest;
|
|
/*
|
* If this isn't the outermost nesting, we don't have to update
|
* @rb->user_page->data_head.
|
*/
|
nest = READ_ONCE(rb->nest);
|
if (nest > 1) {
|
WRITE_ONCE(rb->nest, nest - 1);
|
goto out;
|
}
|
|
again:
|
/*
|
* In order to avoid publishing a head value that goes backwards,
|
* we must ensure the load of @rb->head happens after we've
|
* incremented @rb->nest.
|
*
|
* Otherwise we can observe a @rb->head value before one published
|
* by an IRQ/NMI happening between the load and the increment.
|
*/
|
barrier();
|
head = local_read(&rb->head);
|
|
/*
|
* IRQ/NMI can happen here and advance @rb->head, causing our
|
* load above to be stale.
|
*/
|
|
/*
|
* Since the mmap() consumer (userspace) can run on a different CPU:
|
*
|
* kernel user
|
*
|
* if (LOAD ->data_tail) { LOAD ->data_head
|
* (A) smp_rmb() (C)
|
* STORE $data LOAD $data
|
* smp_wmb() (B) smp_mb() (D)
|
* STORE ->data_head STORE ->data_tail
|
* }
|
*
|
* Where A pairs with D, and B pairs with C.
|
*
|
* In our case (A) is a control dependency that separates the load of
|
* the ->data_tail and the stores of $data. In case ->data_tail
|
* indicates there is no room in the buffer to store $data we do not.
|
*
|
* D needs to be a full barrier since it separates the data READ
|
* from the tail WRITE.
|
*
|
* For B a WMB is sufficient since it separates two WRITEs, and for C
|
* an RMB is sufficient since it separates two READs.
|
*
|
* See perf_output_begin().
|
*/
|
smp_wmb(); /* B, matches C */
|
WRITE_ONCE(rb->user_page->data_head, head);
|
|
/*
|
* We must publish the head before decrementing the nest count,
|
* otherwise an IRQ/NMI can publish a more recent head value and our
|
* write will (temporarily) publish a stale value.
|
*/
|
barrier();
|
WRITE_ONCE(rb->nest, 0);
|
|
/*
|
* Ensure we decrement @rb->nest before we validate the @rb->head.
|
* Otherwise we cannot be sure we caught the 'last' nested update.
|
*/
|
barrier();
|
if (unlikely(head != local_read(&rb->head))) {
|
WRITE_ONCE(rb->nest, 1);
|
goto again;
|
}
|
|
if (handle->wakeup != local_read(&rb->wakeup))
|
perf_output_wakeup(handle);
|
|
out:
|
preempt_enable();
|
}
|
|
static __always_inline bool
|
ring_buffer_has_space(unsigned long head, unsigned long tail,
|
unsigned long data_size, unsigned int size,
|
bool backward)
|
{
|
if (!backward)
|
return CIRC_SPACE(head, tail, data_size) >= size;
|
else
|
return CIRC_SPACE(tail, head, data_size) >= size;
|
}
|
|
static __always_inline int
|
__perf_output_begin(struct perf_output_handle *handle,
|
struct perf_sample_data *data,
|
struct perf_event *event, unsigned int size,
|
bool backward)
|
{
|
struct perf_buffer *rb;
|
unsigned long tail, offset, head;
|
int have_lost, page_shift;
|
struct {
|
struct perf_event_header header;
|
u64 id;
|
u64 lost;
|
} lost_event;
|
|
rcu_read_lock();
|
/*
|
* For inherited events we send all the output towards the parent.
|
*/
|
if (event->parent)
|
event = event->parent;
|
|
rb = rcu_dereference(event->rb);
|
if (unlikely(!rb))
|
goto out;
|
|
if (unlikely(rb->paused)) {
|
if (rb->nr_pages)
|
local_inc(&rb->lost);
|
goto out;
|
}
|
|
handle->rb = rb;
|
handle->event = event;
|
|
have_lost = local_read(&rb->lost);
|
if (unlikely(have_lost)) {
|
size += sizeof(lost_event);
|
if (event->attr.sample_id_all)
|
size += event->id_header_size;
|
}
|
|
perf_output_get_handle(handle);
|
|
do {
|
tail = READ_ONCE(rb->user_page->data_tail);
|
offset = head = local_read(&rb->head);
|
if (!rb->overwrite) {
|
if (unlikely(!ring_buffer_has_space(head, tail,
|
perf_data_size(rb),
|
size, backward)))
|
goto fail;
|
}
|
|
/*
|
* The above forms a control dependency barrier separating the
|
* @tail load above from the data stores below. Since the @tail
|
* load is required to compute the branch to fail below.
|
*
|
* A, matches D; the full memory barrier userspace SHOULD issue
|
* after reading the data and before storing the new tail
|
* position.
|
*
|
* See perf_output_put_handle().
|
*/
|
|
if (!backward)
|
head += size;
|
else
|
head -= size;
|
} while (local_cmpxchg(&rb->head, offset, head) != offset);
|
|
if (backward) {
|
offset = head;
|
head = (u64)(-head);
|
}
|
|
/*
|
* We rely on the implied barrier() by local_cmpxchg() to ensure
|
* none of the data stores below can be lifted up by the compiler.
|
*/
|
|
if (unlikely(head - local_read(&rb->wakeup) > rb->watermark))
|
local_add(rb->watermark, &rb->wakeup);
|
|
page_shift = PAGE_SHIFT + page_order(rb);
|
|
handle->page = (offset >> page_shift) & (rb->nr_pages - 1);
|
offset &= (1UL << page_shift) - 1;
|
handle->addr = rb->data_pages[handle->page] + offset;
|
handle->size = (1UL << page_shift) - offset;
|
|
if (unlikely(have_lost)) {
|
lost_event.header.size = sizeof(lost_event);
|
lost_event.header.type = PERF_RECORD_LOST;
|
lost_event.header.misc = 0;
|
lost_event.id = event->id;
|
lost_event.lost = local_xchg(&rb->lost, 0);
|
|
/* XXX mostly redundant; @data is already fully initializes */
|
perf_event_header__init_id(&lost_event.header, data, event);
|
perf_output_put(handle, lost_event);
|
perf_event__output_id_sample(event, handle, data);
|
}
|
|
return 0;
|
|
fail:
|
local_inc(&rb->lost);
|
perf_output_put_handle(handle);
|
out:
|
rcu_read_unlock();
|
|
return -ENOSPC;
|
}
|
|
int perf_output_begin_forward(struct perf_output_handle *handle,
|
struct perf_sample_data *data,
|
struct perf_event *event, unsigned int size)
|
{
|
return __perf_output_begin(handle, data, event, size, false);
|
}
|
|
int perf_output_begin_backward(struct perf_output_handle *handle,
|
struct perf_sample_data *data,
|
struct perf_event *event, unsigned int size)
|
{
|
return __perf_output_begin(handle, data, event, size, true);
|
}
|
|
int perf_output_begin(struct perf_output_handle *handle,
|
struct perf_sample_data *data,
|
struct perf_event *event, unsigned int size)
|
{
|
|
return __perf_output_begin(handle, data, event, size,
|
unlikely(is_write_backward(event)));
|
}
|
|
unsigned int perf_output_copy(struct perf_output_handle *handle,
|
const void *buf, unsigned int len)
|
{
|
return __output_copy(handle, buf, len);
|
}
|
|
unsigned int perf_output_skip(struct perf_output_handle *handle,
|
unsigned int len)
|
{
|
return __output_skip(handle, NULL, len);
|
}
|
|
void perf_output_end(struct perf_output_handle *handle)
|
{
|
perf_output_put_handle(handle);
|
rcu_read_unlock();
|
}
|
|
static void
|
ring_buffer_init(struct perf_buffer *rb, long watermark, int flags)
|
{
|
long max_size = perf_data_size(rb);
|
|
if (watermark)
|
rb->watermark = min(max_size, watermark);
|
|
if (!rb->watermark)
|
rb->watermark = max_size / 2;
|
|
if (flags & RING_BUFFER_WRITABLE)
|
rb->overwrite = 0;
|
else
|
rb->overwrite = 1;
|
|
refcount_set(&rb->refcount, 1);
|
|
INIT_LIST_HEAD(&rb->event_list);
|
spin_lock_init(&rb->event_lock);
|
|
/*
|
* perf_output_begin() only checks rb->paused, therefore
|
* rb->paused must be true if we have no pages for output.
|
*/
|
if (!rb->nr_pages)
|
rb->paused = 1;
|
}
|
|
void perf_aux_output_flag(struct perf_output_handle *handle, u64 flags)
|
{
|
/*
|
* OVERWRITE is determined by perf_aux_output_end() and can't
|
* be passed in directly.
|
*/
|
if (WARN_ON_ONCE(flags & PERF_AUX_FLAG_OVERWRITE))
|
return;
|
|
handle->aux_flags |= flags;
|
}
|
EXPORT_SYMBOL_GPL(perf_aux_output_flag);
|
|
/*
|
* This is called before hardware starts writing to the AUX area to
|
* obtain an output handle and make sure there's room in the buffer.
|
* When the capture completes, call perf_aux_output_end() to commit
|
* the recorded data to the buffer.
|
*
|
* The ordering is similar to that of perf_output_{begin,end}, with
|
* the exception of (B), which should be taken care of by the pmu
|
* driver, since ordering rules will differ depending on hardware.
|
*
|
* Call this from pmu::start(); see the comment in perf_aux_output_end()
|
* about its use in pmu callbacks. Both can also be called from the PMI
|
* handler if needed.
|
*/
|
void *perf_aux_output_begin(struct perf_output_handle *handle,
|
struct perf_event *event)
|
{
|
struct perf_event *output_event = event;
|
unsigned long aux_head, aux_tail;
|
struct perf_buffer *rb;
|
unsigned int nest;
|
|
if (output_event->parent)
|
output_event = output_event->parent;
|
|
/*
|
* Since this will typically be open across pmu::add/pmu::del, we
|
* grab ring_buffer's refcount instead of holding rcu read lock
|
* to make sure it doesn't disappear under us.
|
*/
|
rb = ring_buffer_get(output_event);
|
if (!rb)
|
return NULL;
|
|
if (!rb_has_aux(rb))
|
goto err;
|
|
/*
|
* If aux_mmap_count is zero, the aux buffer is in perf_mmap_close(),
|
* about to get freed, so we leave immediately.
|
*
|
* Checking rb::aux_mmap_count and rb::refcount has to be done in
|
* the same order, see perf_mmap_close. Otherwise we end up freeing
|
* aux pages in this path, which is a bug, because in_atomic().
|
*/
|
if (!atomic_read(&rb->aux_mmap_count))
|
goto err;
|
|
if (!refcount_inc_not_zero(&rb->aux_refcount))
|
goto err;
|
|
nest = READ_ONCE(rb->aux_nest);
|
/*
|
* Nesting is not supported for AUX area, make sure nested
|
* writers are caught early
|
*/
|
if (WARN_ON_ONCE(nest))
|
goto err_put;
|
|
WRITE_ONCE(rb->aux_nest, nest + 1);
|
|
aux_head = rb->aux_head;
|
|
handle->rb = rb;
|
handle->event = event;
|
handle->head = aux_head;
|
handle->size = 0;
|
handle->aux_flags = 0;
|
|
/*
|
* In overwrite mode, AUX data stores do not depend on aux_tail,
|
* therefore (A) control dependency barrier does not exist. The
|
* (B) <-> (C) ordering is still observed by the pmu driver.
|
*/
|
if (!rb->aux_overwrite) {
|
aux_tail = READ_ONCE(rb->user_page->aux_tail);
|
handle->wakeup = rb->aux_wakeup + rb->aux_watermark;
|
if (aux_head - aux_tail < perf_aux_size(rb))
|
handle->size = CIRC_SPACE(aux_head, aux_tail, perf_aux_size(rb));
|
|
/*
|
* handle->size computation depends on aux_tail load; this forms a
|
* control dependency barrier separating aux_tail load from aux data
|
* store that will be enabled on successful return
|
*/
|
if (!handle->size) { /* A, matches D */
|
event->pending_disable = smp_processor_id();
|
perf_output_wakeup(handle);
|
WRITE_ONCE(rb->aux_nest, 0);
|
goto err_put;
|
}
|
}
|
|
return handle->rb->aux_priv;
|
|
err_put:
|
/* can't be last */
|
rb_free_aux(rb);
|
|
err:
|
ring_buffer_put(rb);
|
handle->event = NULL;
|
|
return NULL;
|
}
|
EXPORT_SYMBOL_GPL(perf_aux_output_begin);
|
|
static __always_inline bool rb_need_aux_wakeup(struct perf_buffer *rb)
|
{
|
if (rb->aux_overwrite)
|
return false;
|
|
if (rb->aux_head - rb->aux_wakeup >= rb->aux_watermark) {
|
rb->aux_wakeup = rounddown(rb->aux_head, rb->aux_watermark);
|
return true;
|
}
|
|
return false;
|
}
|
|
/*
|
* Commit the data written by hardware into the ring buffer by adjusting
|
* aux_head and posting a PERF_RECORD_AUX into the perf buffer. It is the
|
* pmu driver's responsibility to observe ordering rules of the hardware,
|
* so that all the data is externally visible before this is called.
|
*
|
* Note: this has to be called from pmu::stop() callback, as the assumption
|
* of the AUX buffer management code is that after pmu::stop(), the AUX
|
* transaction must be stopped and therefore drop the AUX reference count.
|
*/
|
void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size)
|
{
|
bool wakeup = !!(handle->aux_flags & PERF_AUX_FLAG_TRUNCATED);
|
struct perf_buffer *rb = handle->rb;
|
unsigned long aux_head;
|
|
/* in overwrite mode, driver provides aux_head via handle */
|
if (rb->aux_overwrite) {
|
handle->aux_flags |= PERF_AUX_FLAG_OVERWRITE;
|
|
aux_head = handle->head;
|
rb->aux_head = aux_head;
|
} else {
|
handle->aux_flags &= ~PERF_AUX_FLAG_OVERWRITE;
|
|
aux_head = rb->aux_head;
|
rb->aux_head += size;
|
}
|
|
/*
|
* Only send RECORD_AUX if we have something useful to communicate
|
*
|
* Note: the OVERWRITE records by themselves are not considered
|
* useful, as they don't communicate any *new* information,
|
* aside from the short-lived offset, that becomes history at
|
* the next event sched-in and therefore isn't useful.
|
* The userspace that needs to copy out AUX data in overwrite
|
* mode should know to use user_page::aux_head for the actual
|
* offset. So, from now on we don't output AUX records that
|
* have *only* OVERWRITE flag set.
|
*/
|
if (size || (handle->aux_flags & ~(u64)PERF_AUX_FLAG_OVERWRITE))
|
perf_event_aux_event(handle->event, aux_head, size,
|
handle->aux_flags);
|
|
WRITE_ONCE(rb->user_page->aux_head, rb->aux_head);
|
if (rb_need_aux_wakeup(rb))
|
wakeup = true;
|
|
if (wakeup) {
|
if (handle->aux_flags & PERF_AUX_FLAG_TRUNCATED)
|
handle->event->pending_disable = smp_processor_id();
|
perf_output_wakeup(handle);
|
}
|
|
handle->event = NULL;
|
|
WRITE_ONCE(rb->aux_nest, 0);
|
/* can't be last */
|
rb_free_aux(rb);
|
ring_buffer_put(rb);
|
}
|
EXPORT_SYMBOL_GPL(perf_aux_output_end);
|
|
/*
|
* Skip over a given number of bytes in the AUX buffer, due to, for example,
|
* hardware's alignment constraints.
|
*/
|
int perf_aux_output_skip(struct perf_output_handle *handle, unsigned long size)
|
{
|
struct perf_buffer *rb = handle->rb;
|
|
if (size > handle->size)
|
return -ENOSPC;
|
|
rb->aux_head += size;
|
|
WRITE_ONCE(rb->user_page->aux_head, rb->aux_head);
|
if (rb_need_aux_wakeup(rb)) {
|
perf_output_wakeup(handle);
|
handle->wakeup = rb->aux_wakeup + rb->aux_watermark;
|
}
|
|
handle->head = rb->aux_head;
|
handle->size -= size;
|
|
return 0;
|
}
|
EXPORT_SYMBOL_GPL(perf_aux_output_skip);
|
|
void *perf_get_aux(struct perf_output_handle *handle)
|
{
|
/* this is only valid between perf_aux_output_begin and *_end */
|
if (!handle->event)
|
return NULL;
|
|
return handle->rb->aux_priv;
|
}
|
EXPORT_SYMBOL_GPL(perf_get_aux);
|
|
/*
|
* Copy out AUX data from an AUX handle.
|
*/
|
long perf_output_copy_aux(struct perf_output_handle *aux_handle,
|
struct perf_output_handle *handle,
|
unsigned long from, unsigned long to)
|
{
|
struct perf_buffer *rb = aux_handle->rb;
|
unsigned long tocopy, remainder, len = 0;
|
void *addr;
|
|
from &= (rb->aux_nr_pages << PAGE_SHIFT) - 1;
|
to &= (rb->aux_nr_pages << PAGE_SHIFT) - 1;
|
|
do {
|
tocopy = PAGE_SIZE - offset_in_page(from);
|
if (to > from)
|
tocopy = min(tocopy, to - from);
|
if (!tocopy)
|
break;
|
|
addr = rb->aux_pages[from >> PAGE_SHIFT];
|
addr += offset_in_page(from);
|
|
remainder = perf_output_copy(handle, addr, tocopy);
|
if (remainder)
|
return -EFAULT;
|
|
len += tocopy;
|
from += tocopy;
|
from &= (rb->aux_nr_pages << PAGE_SHIFT) - 1;
|
} while (to != from);
|
|
return len;
|
}
|
|
#define PERF_AUX_GFP (GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_NORETRY)
|
|
static struct page *rb_alloc_aux_page(int node, int order)
|
{
|
struct page *page;
|
|
if (order > MAX_ORDER)
|
order = MAX_ORDER;
|
|
do {
|
page = alloc_pages_node(node, PERF_AUX_GFP, order);
|
} while (!page && order--);
|
|
if (page && order) {
|
/*
|
* Communicate the allocation size to the driver:
|
* if we managed to secure a high-order allocation,
|
* set its first page's private to this order;
|
* !PagePrivate(page) means it's just a normal page.
|
*/
|
split_page(page, order);
|
SetPagePrivate(page);
|
set_page_private(page, order);
|
}
|
|
return page;
|
}
|
|
static void rb_free_aux_page(struct perf_buffer *rb, int idx)
|
{
|
struct page *page = virt_to_page(rb->aux_pages[idx]);
|
|
ClearPagePrivate(page);
|
page->mapping = NULL;
|
__free_page(page);
|
}
|
|
static void __rb_free_aux(struct perf_buffer *rb)
|
{
|
int pg;
|
|
/*
|
* Should never happen, the last reference should be dropped from
|
* perf_mmap_close() path, which first stops aux transactions (which
|
* in turn are the atomic holders of aux_refcount) and then does the
|
* last rb_free_aux().
|
*/
|
WARN_ON_ONCE(in_atomic());
|
|
if (rb->aux_priv) {
|
rb->free_aux(rb->aux_priv);
|
rb->free_aux = NULL;
|
rb->aux_priv = NULL;
|
}
|
|
if (rb->aux_nr_pages) {
|
for (pg = 0; pg < rb->aux_nr_pages; pg++)
|
rb_free_aux_page(rb, pg);
|
|
kfree(rb->aux_pages);
|
rb->aux_nr_pages = 0;
|
}
|
}
|
|
int rb_alloc_aux(struct perf_buffer *rb, struct perf_event *event,
|
pgoff_t pgoff, int nr_pages, long watermark, int flags)
|
{
|
bool overwrite = !(flags & RING_BUFFER_WRITABLE);
|
int node = (event->cpu == -1) ? -1 : cpu_to_node(event->cpu);
|
int ret = -ENOMEM, max_order;
|
|
if (!has_aux(event))
|
return -EOPNOTSUPP;
|
|
/*
|
* We need to start with the max_order that fits in nr_pages,
|
* not the other way around, hence ilog2() and not get_order.
|
*/
|
max_order = ilog2(nr_pages);
|
|
/*
|
* PMU requests more than one contiguous chunks of memory
|
* for SW double buffering
|
*/
|
if (!overwrite) {
|
if (!max_order)
|
return -EINVAL;
|
|
max_order--;
|
}
|
|
rb->aux_pages = kcalloc_node(nr_pages, sizeof(void *), GFP_KERNEL,
|
node);
|
if (!rb->aux_pages)
|
return -ENOMEM;
|
|
rb->free_aux = event->pmu->free_aux;
|
for (rb->aux_nr_pages = 0; rb->aux_nr_pages < nr_pages;) {
|
struct page *page;
|
int last, order;
|
|
order = min(max_order, ilog2(nr_pages - rb->aux_nr_pages));
|
page = rb_alloc_aux_page(node, order);
|
if (!page)
|
goto out;
|
|
for (last = rb->aux_nr_pages + (1 << page_private(page));
|
last > rb->aux_nr_pages; rb->aux_nr_pages++)
|
rb->aux_pages[rb->aux_nr_pages] = page_address(page++);
|
}
|
|
/*
|
* In overwrite mode, PMUs that don't support SG may not handle more
|
* than one contiguous allocation, since they rely on PMI to do double
|
* buffering. In this case, the entire buffer has to be one contiguous
|
* chunk.
|
*/
|
if ((event->pmu->capabilities & PERF_PMU_CAP_AUX_NO_SG) &&
|
overwrite) {
|
struct page *page = virt_to_page(rb->aux_pages[0]);
|
|
if (page_private(page) != max_order)
|
goto out;
|
}
|
|
rb->aux_priv = event->pmu->setup_aux(event, rb->aux_pages, nr_pages,
|
overwrite);
|
if (!rb->aux_priv)
|
goto out;
|
|
ret = 0;
|
|
/*
|
* aux_pages (and pmu driver's private data, aux_priv) will be
|
* referenced in both producer's and consumer's contexts, thus
|
* we keep a refcount here to make sure either of the two can
|
* reference them safely.
|
*/
|
refcount_set(&rb->aux_refcount, 1);
|
|
rb->aux_overwrite = overwrite;
|
rb->aux_watermark = watermark;
|
|
if (!rb->aux_watermark && !rb->aux_overwrite)
|
rb->aux_watermark = nr_pages << (PAGE_SHIFT - 1);
|
|
out:
|
if (!ret)
|
rb->aux_pgoff = pgoff;
|
else
|
__rb_free_aux(rb);
|
|
return ret;
|
}
|
|
void rb_free_aux(struct perf_buffer *rb)
|
{
|
if (refcount_dec_and_test(&rb->aux_refcount))
|
__rb_free_aux(rb);
|
}
|
|
#ifndef CONFIG_PERF_USE_VMALLOC
|
|
/*
|
* Back perf_mmap() with regular GFP_KERNEL-0 pages.
|
*/
|
|
static struct page *
|
__perf_mmap_to_page(struct perf_buffer *rb, unsigned long pgoff)
|
{
|
if (pgoff > rb->nr_pages)
|
return NULL;
|
|
if (pgoff == 0)
|
return virt_to_page(rb->user_page);
|
|
return virt_to_page(rb->data_pages[pgoff - 1]);
|
}
|
|
static void *perf_mmap_alloc_page(int cpu)
|
{
|
struct page *page;
|
int node;
|
|
node = (cpu == -1) ? cpu : cpu_to_node(cpu);
|
page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
|
if (!page)
|
return NULL;
|
|
return page_address(page);
|
}
|
|
static void perf_mmap_free_page(void *addr)
|
{
|
struct page *page = virt_to_page(addr);
|
|
page->mapping = NULL;
|
__free_page(page);
|
}
|
|
struct perf_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
|
{
|
struct perf_buffer *rb;
|
unsigned long size;
|
int i;
|
|
size = sizeof(struct perf_buffer);
|
size += nr_pages * sizeof(void *);
|
|
if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)
|
goto fail;
|
|
rb = kzalloc(size, GFP_KERNEL);
|
if (!rb)
|
goto fail;
|
|
rb->user_page = perf_mmap_alloc_page(cpu);
|
if (!rb->user_page)
|
goto fail_user_page;
|
|
for (i = 0; i < nr_pages; i++) {
|
rb->data_pages[i] = perf_mmap_alloc_page(cpu);
|
if (!rb->data_pages[i])
|
goto fail_data_pages;
|
}
|
|
rb->nr_pages = nr_pages;
|
|
ring_buffer_init(rb, watermark, flags);
|
|
return rb;
|
|
fail_data_pages:
|
for (i--; i >= 0; i--)
|
perf_mmap_free_page(rb->data_pages[i]);
|
|
perf_mmap_free_page(rb->user_page);
|
|
fail_user_page:
|
kfree(rb);
|
|
fail:
|
return NULL;
|
}
|
|
void rb_free(struct perf_buffer *rb)
|
{
|
int i;
|
|
perf_mmap_free_page(rb->user_page);
|
for (i = 0; i < rb->nr_pages; i++)
|
perf_mmap_free_page(rb->data_pages[i]);
|
kfree(rb);
|
}
|
|
#else
|
static struct page *
|
__perf_mmap_to_page(struct perf_buffer *rb, unsigned long pgoff)
|
{
|
/* The '>' counts in the user page. */
|
if (pgoff > data_page_nr(rb))
|
return NULL;
|
|
return vmalloc_to_page((void *)rb->user_page + pgoff * PAGE_SIZE);
|
}
|
|
static void perf_mmap_unmark_page(void *addr)
|
{
|
struct page *page = vmalloc_to_page(addr);
|
|
page->mapping = NULL;
|
}
|
|
static void rb_free_work(struct work_struct *work)
|
{
|
struct perf_buffer *rb;
|
void *base;
|
int i, nr;
|
|
rb = container_of(work, struct perf_buffer, work);
|
nr = data_page_nr(rb);
|
|
base = rb->user_page;
|
/* The '<=' counts in the user page. */
|
for (i = 0; i <= nr; i++)
|
perf_mmap_unmark_page(base + (i * PAGE_SIZE));
|
|
vfree(base);
|
kfree(rb);
|
}
|
|
void rb_free(struct perf_buffer *rb)
|
{
|
schedule_work(&rb->work);
|
}
|
|
struct perf_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
|
{
|
struct perf_buffer *rb;
|
unsigned long size;
|
void *all_buf;
|
|
size = sizeof(struct perf_buffer);
|
size += sizeof(void *);
|
|
rb = kzalloc(size, GFP_KERNEL);
|
if (!rb)
|
goto fail;
|
|
INIT_WORK(&rb->work, rb_free_work);
|
|
all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
|
if (!all_buf)
|
goto fail_all_buf;
|
|
rb->user_page = all_buf;
|
rb->data_pages[0] = all_buf + PAGE_SIZE;
|
if (nr_pages) {
|
rb->nr_pages = 1;
|
rb->page_order = ilog2(nr_pages);
|
}
|
|
ring_buffer_init(rb, watermark, flags);
|
|
return rb;
|
|
fail_all_buf:
|
kfree(rb);
|
|
fail:
|
return NULL;
|
}
|
|
#endif
|
|
struct page *
|
perf_mmap_to_page(struct perf_buffer *rb, unsigned long pgoff)
|
{
|
if (rb->aux_nr_pages) {
|
/* above AUX space */
|
if (pgoff > rb->aux_pgoff + rb->aux_nr_pages)
|
return NULL;
|
|
/* AUX space */
|
if (pgoff >= rb->aux_pgoff) {
|
int aux_pgoff = array_index_nospec(pgoff - rb->aux_pgoff, rb->aux_nr_pages);
|
return virt_to_page(rb->aux_pages[aux_pgoff]);
|
}
|
}
|
|
return __perf_mmap_to_page(rb, pgoff);
|
}
|
