// SPDX-License-Identifier: GPL-2.0
/*
* Performance events ring-buffer code:
*
* Copyright (C) 2008 Thomas Gleixner <[email protected]>
* Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
* Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
* Copyright © 2009 Paul Mackerras, IBM Corp. <[email protected]>
*/
#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;
if (*perf_event_fasync(handle->event) && !handle->event->pending_kill)
handle->event->pending_kill = POLL_IN;
irq_work_queue(&handle->event->pending_irq);
}
/*
* 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);
atomic64_inc(&event->lost_samples);
}
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);
offset = local_read(&rb->head);
do {
head = offset;
tail = READ_ONCE(rb->user_page->data_tail);
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_try_cmpxchg(&rb->head, &offset, head));
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);
atomic64_inc(&event->lost_samples);
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;
mutex_init(&rb->aux_mutex);
}
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_PAGE_ORDER)
order = MAX_PAGE_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;
if (nr_pages <= 0)
return -EINVAL;
if (!overwrite) {
/*
* Watermark defaults to half the buffer, and so does the
* max_order, to aid PMU drivers in double buffering.
*/
if (!watermark)
watermark = min_t(unsigned long,
U32_MAX,
(unsigned long)nr_pages << (PAGE_SHIFT - 1));
/*
* Use aux_watermark as the basis for chunking to
* help PMU drivers honor the watermark.
*/
max_order = get_order(watermark);
} else {
/*
* 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);
watermark = 0;
}
/*
* kcalloc_node() is unable to allocate buffer if the size is larger
* than: PAGE_SIZE << MAX_PAGE_ORDER; directly bail out in this case.
*/
if (get_order((unsigned long)nr_pages * sizeof(void *)) > MAX_PAGE_ORDER)
return -ENOMEM;
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;
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, node;
size = sizeof(struct perf_buffer);
size += nr_pages * sizeof(void *);
if (order_base_2(size) > PAGE_SHIFT+MAX_PAGE_ORDER)
goto fail;
node = (cpu == -1) ? cpu : cpu_to_node(cpu);
rb = kzalloc_node(size, GFP_KERNEL, node);
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;
int node;
size = sizeof(struct perf_buffer);
size += sizeof(void *);
node = (cpu == -1) ? cpu : cpu_to_node(cpu);
rb = kzalloc_node(size, GFP_KERNEL, node);
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);
}
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