#include <linux/perf_event.h>
#include <linux/ftrace_event.h>
#include <linux/hw_breakpoint.h>
+#include <linux/mm_types.h>
#include "internal.h"
/*
* Called when the last reference to the file is gone.
*/
-static int perf_release(struct inode *inode, struct file *file)
+static void put_event(struct perf_event *event)
{
- struct perf_event *event = file->private_data;
struct task_struct *owner;
- file->private_data = NULL;
+ if (!atomic_long_dec_and_test(&event->refcount))
+ return;
rcu_read_lock();
owner = ACCESS_ONCE(event->owner);
put_task_struct(owner);
}
- return perf_event_release_kernel(event);
+ perf_event_release_kernel(event);
+}
+
+static int perf_release(struct inode *inode, struct file *file)
+{
+ put_event(file->private_data);
+ return 0;
}
u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
static const struct file_operations perf_fops;
-static struct perf_event *perf_fget_light(int fd, int *fput_needed)
+static struct file *perf_fget_light(int fd, int *fput_needed)
{
struct file *file;
return ERR_PTR(-EBADF);
}
- return file->private_data;
+ return file;
}
static int perf_event_set_output(struct perf_event *event,
case PERF_EVENT_IOC_SET_OUTPUT:
{
+ struct file *output_file = NULL;
struct perf_event *output_event = NULL;
int fput_needed = 0;
int ret;
if (arg != -1) {
- output_event = perf_fget_light(arg, &fput_needed);
- if (IS_ERR(output_event))
- return PTR_ERR(output_event);
+ output_file = perf_fget_light(arg, &fput_needed);
+ if (IS_ERR(output_file))
+ return PTR_ERR(output_file);
+ output_event = output_file->private_data;
}
ret = perf_event_set_output(event, output_event);
if (output_event)
- fput_light(output_event->filp, fput_needed);
+ fput_light(output_file, fput_needed);
return ret;
}
}
EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
+static void
+perf_output_sample_regs(struct perf_output_handle *handle,
+ struct pt_regs *regs, u64 mask)
+{
+ int bit;
+
+ for_each_set_bit(bit, (const unsigned long *) &mask,
+ sizeof(mask) * BITS_PER_BYTE) {
+ u64 val;
+
+ val = perf_reg_value(regs, bit);
+ perf_output_put(handle, val);
+ }
+}
+
+static void perf_sample_regs_user(struct perf_regs_user *regs_user,
+ struct pt_regs *regs)
+{
+ if (!user_mode(regs)) {
+ if (current->mm)
+ regs = task_pt_regs(current);
+ else
+ regs = NULL;
+ }
+
+ if (regs) {
+ regs_user->regs = regs;
+ regs_user->abi = perf_reg_abi(current);
+ }
+}
+
+/*
+ * Get remaining task size from user stack pointer.
+ *
+ * It'd be better to take stack vma map and limit this more
+ * precisly, but there's no way to get it safely under interrupt,
+ * so using TASK_SIZE as limit.
+ */
+static u64 perf_ustack_task_size(struct pt_regs *regs)
+{
+ unsigned long addr = perf_user_stack_pointer(regs);
+
+ if (!addr || addr >= TASK_SIZE)
+ return 0;
+
+ return TASK_SIZE - addr;
+}
+
+static u16
+perf_sample_ustack_size(u16 stack_size, u16 header_size,
+ struct pt_regs *regs)
+{
+ u64 task_size;
+
+ /* No regs, no stack pointer, no dump. */
+ if (!regs)
+ return 0;
+
+ /*
+ * Check if we fit in with the requested stack size into the:
+ * - TASK_SIZE
+ * If we don't, we limit the size to the TASK_SIZE.
+ *
+ * - remaining sample size
+ * If we don't, we customize the stack size to
+ * fit in to the remaining sample size.
+ */
+
+ task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
+ stack_size = min(stack_size, (u16) task_size);
+
+ /* Current header size plus static size and dynamic size. */
+ header_size += 2 * sizeof(u64);
+
+ /* Do we fit in with the current stack dump size? */
+ if ((u16) (header_size + stack_size) < header_size) {
+ /*
+ * If we overflow the maximum size for the sample,
+ * we customize the stack dump size to fit in.
+ */
+ stack_size = USHRT_MAX - header_size - sizeof(u64);
+ stack_size = round_up(stack_size, sizeof(u64));
+ }
+
+ return stack_size;
+}
+
+static void
+perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
+ struct pt_regs *regs)
+{
+ /* Case of a kernel thread, nothing to dump */
+ if (!regs) {
+ u64 size = 0;
+ perf_output_put(handle, size);
+ } else {
+ unsigned long sp;
+ unsigned int rem;
+ u64 dyn_size;
+
+ /*
+ * We dump:
+ * static size
+ * - the size requested by user or the best one we can fit
+ * in to the sample max size
+ * data
+ * - user stack dump data
+ * dynamic size
+ * - the actual dumped size
+ */
+
+ /* Static size. */
+ perf_output_put(handle, dump_size);
+
+ /* Data. */
+ sp = perf_user_stack_pointer(regs);
+ rem = __output_copy_user(handle, (void *) sp, dump_size);
+ dyn_size = dump_size - rem;
+
+ perf_output_skip(handle, rem);
+
+ /* Dynamic size. */
+ perf_output_put(handle, dyn_size);
+ }
+}
+
static void __perf_event_header__init_id(struct perf_event_header *header,
struct perf_sample_data *data,
struct perf_event *event)
perf_output_put(handle, nr);
}
}
+
+ if (sample_type & PERF_SAMPLE_REGS_USER) {
+ u64 abi = data->regs_user.abi;
+
+ /*
+ * If there are no regs to dump, notice it through
+ * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
+ */
+ perf_output_put(handle, abi);
+
+ if (abi) {
+ u64 mask = event->attr.sample_regs_user;
+ perf_output_sample_regs(handle,
+ data->regs_user.regs,
+ mask);
+ }
+ }
+
+ if (sample_type & PERF_SAMPLE_STACK_USER)
+ perf_output_sample_ustack(handle,
+ data->stack_user_size,
+ data->regs_user.regs);
}
void perf_prepare_sample(struct perf_event_header *header,
}
header->size += size;
}
+
+ if (sample_type & PERF_SAMPLE_REGS_USER) {
+ /* regs dump ABI info */
+ int size = sizeof(u64);
+
+ perf_sample_regs_user(&data->regs_user, regs);
+
+ if (data->regs_user.regs) {
+ u64 mask = event->attr.sample_regs_user;
+ size += hweight64(mask) * sizeof(u64);
+ }
+
+ header->size += size;
+ }
+
+ if (sample_type & PERF_SAMPLE_STACK_USER) {
+ /*
+ * Either we need PERF_SAMPLE_STACK_USER bit to be allways
+ * processed as the last one or have additional check added
+ * in case new sample type is added, because we could eat
+ * up the rest of the sample size.
+ */
+ struct perf_regs_user *uregs = &data->regs_user;
+ u16 stack_size = event->attr.sample_stack_user;
+ u16 size = sizeof(u64);
+
+ if (!uregs->abi)
+ perf_sample_regs_user(uregs, regs);
+
+ stack_size = perf_sample_ustack_size(stack_size, header->size,
+ uregs->regs);
+
+ /*
+ * If there is something to dump, add space for the dump
+ * itself and for the field that tells the dynamic size,
+ * which is how many have been actually dumped.
+ */
+ if (stack_size)
+ size += sizeof(u64) + stack_size;
+
+ data->stack_user_size = stack_size;
+ header->size += size;
+ }
}
static void perf_event_output(struct perf_event *event,
mutex_init(&event->mmap_mutex);
+ atomic_long_set(&event->refcount, 1);
event->cpu = cpu;
event->attr = *attr;
event->group_leader = group_leader;
attr->branch_sample_type = mask;
}
}
+
+ if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
+ ret = perf_reg_validate(attr->sample_regs_user);
+ if (ret)
+ return ret;
+ }
+
+ if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
+ if (!arch_perf_have_user_stack_dump())
+ return -ENOSYS;
+
+ /*
+ * We have __u32 type for the size, but so far
+ * we can only use __u16 as maximum due to the
+ * __u16 sample size limit.
+ */
+ if (attr->sample_stack_user >= USHRT_MAX)
+ ret = -EINVAL;
+ else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
+ ret = -EINVAL;
+ }
+
out:
return ret;
if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
return -EINVAL;
- event_fd = get_unused_fd_flags(O_RDWR);
+ event_fd = get_unused_fd();
if (event_fd < 0)
return event_fd;
if (group_fd != -1) {
- group_leader = perf_fget_light(group_fd, &fput_needed);
- if (IS_ERR(group_leader)) {
- err = PTR_ERR(group_leader);
+ group_file = perf_fget_light(group_fd, &fput_needed);
+ if (IS_ERR(group_file)) {
+ err = PTR_ERR(group_file);
goto err_fd;
}
- group_file = group_leader->filp;
+ group_leader = group_file->private_data;
if (flags & PERF_FLAG_FD_OUTPUT)
output_event = group_leader;
if (flags & PERF_FLAG_FD_NO_GROUP)
put_ctx(gctx);
}
- event->filp = event_file;
WARN_ON_ONCE(ctx->parent_ctx);
mutex_lock(&ctx->mutex);
goto err_free;
}
- event->filp = NULL;
WARN_ON_ONCE(ctx->parent_ctx);
mutex_lock(&ctx->mutex);
perf_install_in_context(ctx, event, cpu);
* Release the parent event, if this was the last
* reference to it.
*/
- fput(parent_event->filp);
+ put_event(parent_event);
}
static void
*
* __perf_event_exit_task()
* sync_child_event()
- * fput(parent_event->filp)
- * perf_release()
- * mutex_lock(&ctx->mutex)
+ * put_event()
+ * mutex_lock(&ctx->mutex)
*
* But since its the parent context it won't be the same instance.
*/
list_del_init(&event->child_list);
mutex_unlock(&parent->child_mutex);
- fput(parent->filp);
+ put_event(parent);
perf_group_detach(event);
list_del_event(event, ctx);
NULL, NULL);
if (IS_ERR(child_event))
return child_event;
+
+ if (!atomic_long_inc_not_zero(&parent_event->refcount)) {
+ free_event(child_event);
+ return NULL;
+ }
+
get_ctx(child_ctx);
/*
add_event_to_ctx(child_event, child_ctx);
raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
- /*
- * Get a reference to the parent filp - we will fput it
- * when the child event exits. This is safe to do because
- * we are in the parent and we know that the filp still
- * exists and has a nonzero count:
- */
- atomic_long_inc(&parent_event->filp->f_count);
-
/*
* Link this into the parent event's child list
*/
projects / karo-tx-linux.git / blobdiff