This patch contains the system calls interface.
--- linux-2.6.17-rc6.orig/perfmon/perfmon_syscalls.c 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.17-rc6/perfmon/perfmon_syscalls.c 2006-06-13 03:08:34.000000000 -0700
@@ -0,0 +1,625 @@
+/*
+ * perfmon_syscalls.c: perfmon2 system call interface
+ *
+ * This file implements the perfmon2 interface which
+ * provides access to the hardware performance counters
+ * of the host processor.
+ *
+ * The initial version of perfmon.c was written by
+ * Ganesh Venkitachalam, IBM Corp.
+ *
+ * Then it was modified for perfmon-1.x by Stephane Eranian and
+ * David Mosberger, Hewlett Packard Co.
+ *
+ * Version Perfmon-2.x is a complete rewrite of perfmon-1.x
+ * by Stephane Eranian, Hewlett Packard Co.
+ *
+ * Copyright (c) 1999-2006 Hewlett-Packard Development Company, L.P.
+ * Contributed by Stephane Eranian <[email protected]>
+ * David Mosberger-Tang <[email protected]>
+ *
+ * More information about perfmon available at:
+ * http://www.hpl.hp.com/research/linux/perfmon
+ */
+#include <linux/kernel.h>
+#include <linux/perfmon.h>
+#include <asm/uaccess.h>
+
+int pfm_check_task_state(struct pfm_context *ctx, int check_mask,
+ unsigned long *flags)
+{
+ struct task_struct *task;
+ unsigned long local_flags, new_flags;
+ int state, old_state;
+
+recheck:
+ /*
+ * task is NULL for system-wide context
+ */
+ task = ctx->task;
+ state = ctx->state;
+ local_flags = *flags;
+
+ PFM_DBG("state=%d [%d] task_state=%ld check_mask=0x%x",
+ state,
+ task ? task->pid : -1,
+ task ? task->state : -1, check_mask);
+
+ if (state == PFM_CTX_UNLOADED)
+ return 0;
+ /*
+ * no command can operate on a zombie context
+ */
+ if (state == PFM_CTX_ZOMBIE)
+ return -EINVAL;
+
+ /*
+ * at this point, state is PFM_CTX_LOADED or PFM_CTX_MASKED
+ */
+
+ /*
+ * some commands require the context to be unloaded to operate
+ */
+ if (check_mask & PFM_CMD_UNLOADED) {
+ PFM_DBG("state=%d, cmd needs unloaded", state);
+ return -EBUSY;
+ }
+
+ /*
+ * self-monitoring always ok.
+ */
+ if (task == current)
+ return 0;
+
+ /*
+ * for syswide, we accept if running on the cpu the context is bound
+ * to. When monitoring another thread, must wait until stopped.
+ */
+ if (ctx->flags.system) {
+ if (ctx->cpu != smp_processor_id())
+ return -EBUSY;
+ return 0;
+ }
+
+ /*
+ * monitoring another thread
+ */
+ if (state == PFM_CTX_MASKED && (check_mask & PFM_CMD_UNLOAD) == 0)
+ return 0;
+ /*
+ * state is PFM_CTX_LOADED.
+ *
+ * We could lift this restriction for UP but it would mean that
+ * the user has no guarantee the task would not run between
+ * two successive calls to perfmonctl(). That's probably OK.
+ * If this user wants to ensure the task does not run, then
+ * the task must be stopped.
+ */
+ if (check_mask & PFM_CMD_STOPPED) {
+ if ((task->state != TASK_STOPPED)
+ && (task->state != TASK_TRACED)) {
+ PFM_DBG("[%d] task not in stopped state", task->pid);
+ return -EBUSY;
+ }
+ /*
+ * task is now stopped, wait for ctxsw out
+ *
+ * This is an interesting point in the code.
+ * We need to unprotect the context because
+ * the pfm_ctxswout_thread() routines needs to grab
+ * the same lock. There are danger in doing
+ * this because it leaves a window open for
+ * another task to get access to the context
+ * and possibly change its state. The one thing
+ * that is not possible is for the context to disappear
+ * because we are protected by the VFS layer, i.e.,
+ * get_fd()/put_fd().
+ */
+ old_state = state;
+
+ PFM_DBG("going wait_inactive for [%d] state=%ld flags=0x%lx",
+ task->pid,
+ task->state,
+ local_flags);
+
+ spin_unlock_irqrestore(&ctx->lock, local_flags);
+
+ wait_task_inactive(task);
+
+ spin_lock_irqsave(&ctx->lock, new_flags);
+
+ /*
+ * flags may be different than when we released the lock
+ */
+ *flags = new_flags;
+
+ /*
+ * we must recheck to verify if state has changed
+ */
+ if (ctx->state != old_state) {
+ PFM_DBG("old_state=%d new_state=%d",
+ old_state,
+ ctx->state);
+ goto recheck;
+ }
+ }
+ return 0;
+}
+
+int pfm_get_args(void __user *ureq, size_t sz, void **req)
+{
+ void *addr;
+
+ if (unlikely(sz > pfm_controls.arg_size_max)) {
+ PFM_DBG("argument too big %zu max=%zu",
+ sz,
+ pfm_controls.arg_size_max);
+ return -E2BIG;
+ }
+
+ addr = kmalloc(sz, GFP_KERNEL);
+ if (unlikely(addr == NULL))
+ return -ENOMEM;
+
+ if (copy_from_user(addr, ureq, sz)) {
+ kfree(addr);
+ return -EFAULT;
+ }
+ *req = addr;
+
+ return 0;
+}
+
+int pfm_get_smpl_arg(pfm_uuid_t uuid, void __user *uaddr, size_t usize, void **arg,
+ struct pfm_smpl_fmt **fmt)
+{
+ struct pfm_smpl_fmt *f;
+ void *addr = NULL;
+ size_t sz;
+ int ret;
+
+ if (!pfm_use_smpl_fmt(uuid))
+ return 0;
+
+ /*
+ * find fmt and increase refcount
+ */
+ f = pfm_smpl_fmt_get(uuid);
+ if (f == NULL) {
+ PFM_DBG("buffer format not found");
+ return -EINVAL;
+ }
+
+ sz = f->fmt_arg_size;
+
+ /*
+ * usize = -1 is for IA-64 backward compatibility
+ */
+ ret = -EINVAL;
+ if (sz != usize && usize != -1) {
+ PFM_DBG("invalid arg size %zu, format expects %zu",
+ usize, sz);
+ goto error;
+ }
+
+ ret = -ENOMEM;
+ addr = kmalloc(sz, GFP_KERNEL);
+ if (addr == NULL)
+ goto error;
+
+ ret = -EFAULT;
+ if (copy_from_user(addr, uaddr, sz))
+ goto error;
+
+ *arg = addr;
+ *fmt = f;
+ return 0;
+
+error:
+ kfree(addr);
+ pfm_smpl_fmt_put(f);
+ return ret;
+}
+
+asmlinkage long sys_pfm_create_context(struct pfarg_ctx __user *ureq, void __user *uarg, size_t smpl_size)
+{
+ struct pfarg_ctx req;
+ struct pfm_context *new_ctx;
+ struct pfm_smpl_fmt *fmt = NULL;
+ void *smpl_arg = NULL;
+ int ret = -EFAULT;
+
+ if (copy_from_user(&req, ureq, sizeof(req)))
+ goto abort;
+
+ ret = pfm_get_smpl_arg(req.ctx_smpl_buf_id, uarg, smpl_size,
+ &smpl_arg, &fmt);
+ if (ret)
+ goto abort;
+
+ ret = __pfm_create_context(&req, fmt, smpl_arg, PFM_NORMAL, NULL, &new_ctx);
+
+ /*
+ * copy_user return value overrides command return value
+ */
+ if (!ret) {
+ if (copy_to_user(ureq, &req, sizeof(req))) {
+ pfm_undo_create_context_fd(req.ctx_fd, new_ctx);
+ ret = -EFAULT;
+ }
+ }
+
+abort:
+ kfree(smpl_arg);
+ return ret;
+}
+
+
+asmlinkage long sys_pfm_write_pmcs(int fd, struct pfarg_pmc __user *ureq, int count)
+{
+ struct pfm_context *ctx;
+ struct pfarg_pmc *req = NULL;
+ unsigned long flags;
+ size_t sz;
+ int ret;
+
+ if (count < 0)
+ return -EINVAL;
+
+ ctx = pfm_get_ctx(fd);
+ if (unlikely(ctx == NULL))
+ return -EBADF;
+
+
+ sz = count*sizeof(*ureq);
+
+ ret = pfm_get_args(ureq, sz, (void **)&req);
+ if (ret)
+ goto error;
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ ret = pfm_check_task_state(ctx, PFM_CMD_STOPPED, &flags);
+ if (ret == 0)
+ ret = __pfm_write_pmcs(ctx, req, count);
+
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ if (copy_to_user(ureq, req, sz))
+ ret = -EFAULT;
+error:
+ kfree(req);
+ pfm_put_ctx(ctx);
+
+ return ret;
+}
+
+asmlinkage long sys_pfm_write_pmds(int fd, struct pfarg_pmd __user *ureq, int count)
+{
+ struct pfm_context *ctx;
+ struct pfarg_pmd *req = NULL;
+ unsigned long flags;
+ size_t sz;
+ int ret;
+
+ if (count < 0)
+ return -EINVAL;
+
+ ctx = pfm_get_ctx(fd);
+ if (unlikely(ctx == NULL))
+ return -EBADF;
+
+
+ sz = count*sizeof(*ureq);
+
+ ret = pfm_get_args(ureq, sz, (void **)&req);
+ if (ret)
+ goto error;
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ ret = pfm_check_task_state(ctx, PFM_CMD_STOPPED, &flags);
+ if (ret == 0)
+ ret = __pfm_write_pmds(ctx, req, count, 0);
+
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ if (copy_to_user(ureq, req, sz))
+ ret = -EFAULT;
+error:
+ kfree(req);
+ pfm_put_ctx(ctx);
+
+ return ret;
+}
+
+asmlinkage long sys_pfm_read_pmds(int fd, struct pfarg_pmd __user *ureq, int count)
+{
+ struct pfm_context *ctx;
+ struct pfarg_pmd *req = NULL;
+ unsigned long flags;
+ size_t sz;
+ int ret;
+
+ if (count < 0)
+ return -EINVAL;
+
+ ctx = pfm_get_ctx(fd);
+ if (unlikely(ctx == NULL))
+ return -EBADF;
+
+ sz = count*sizeof(*ureq);
+
+ ret = pfm_get_args(ureq, sz, (void **)&req);
+ if (ret)
+ goto error;
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ ret = pfm_check_task_state(ctx, PFM_CMD_STOPPED, &flags);
+ if (ret == 0)
+ ret = __pfm_read_pmds(ctx, req, count);
+
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ if (copy_to_user(ureq, req, sz))
+ ret = -EFAULT;
+error:
+ kfree(req);
+ pfm_put_ctx(ctx);
+
+ return ret;
+}
+
+asmlinkage long sys_pfm_restart(int fd)
+{
+ struct pfm_context *ctx;
+ unsigned long flags;
+ int ret = 0;
+
+ ctx = pfm_get_ctx(fd);
+ if (unlikely(ctx == NULL))
+ return -EBADF;
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ ret = pfm_check_task_state(ctx, 0, &flags);
+ if (ret == 0)
+ ret = __pfm_restart(ctx);
+
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ pfm_put_ctx(ctx);
+
+ return ret;
+}
+
+
+asmlinkage long sys_pfm_stop(int fd)
+{
+ struct pfm_context *ctx;
+ unsigned long flags;
+ int ret;
+
+ ctx = pfm_get_ctx(fd);
+ if (unlikely(ctx == NULL))
+ return -EBADF;
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ ret = pfm_check_task_state(ctx, PFM_CMD_STOPPED, &flags);
+ if (ret == 0)
+ ret = __pfm_stop(ctx);
+
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ pfm_put_ctx(ctx);
+
+ return ret;
+}
+
+asmlinkage long sys_pfm_start(int fd, struct pfarg_start __user *ureq)
+{
+ struct pfm_context *ctx;
+ struct pfarg_start req;
+ unsigned long flags;
+ int ret = 0;
+
+ ctx = pfm_get_ctx(fd);
+ if (ctx == NULL)
+ return -EBADF;
+
+ /*
+ * the one argument is actually optional
+ */
+ if (ureq && copy_from_user(&req, ureq, sizeof(req)))
+ return -EFAULT;
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ ret = pfm_check_task_state(ctx, PFM_CMD_STOPPED, &flags);
+ if (ret == 0)
+ ret = __pfm_start(ctx, ureq ? &req : NULL);
+
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ pfm_put_ctx(ctx);
+
+ return ret;
+}
+
+
+
+asmlinkage long sys_pfm_load_context(int fd, struct pfarg_load __user *ureq)
+{
+ struct pfm_context *ctx;
+ unsigned long flags;
+ struct pfarg_load req;
+ int ret;
+
+ ctx = pfm_get_ctx(fd);
+ if (ctx == NULL)
+ return -EBADF;
+
+ if (copy_from_user(&req, ureq, sizeof(req)))
+ return -EFAULT;
+
+ /*
+ * irqsave is required to avoid race in case context is already
+ * loaded or with switch timeout in the case of self-monitoring
+ */
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ ret = pfm_check_task_state(ctx, PFM_CMD_STOPPED, &flags);
+ if (ret == 0)
+ ret = __pfm_load_context(ctx, &req);
+
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ pfm_put_ctx(ctx);
+
+ return ret;
+}
+
+
+asmlinkage long sys_pfm_unload_context(int fd)
+{
+ struct pfm_context *ctx;
+ unsigned long flags;
+ int ret = 0;
+
+ ctx = pfm_get_ctx(fd);
+ if (ctx == NULL)
+ return -EBADF;
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ ret = pfm_check_task_state(ctx, PFM_CMD_STOPPED|PFM_CMD_UNLOAD, &flags);
+ if (ret == 0)
+ ret = __pfm_unload_context(ctx, 0);
+
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ pfm_put_ctx(ctx);
+
+ return ret;
+}
+
+asmlinkage long sys_pfm_delete_evtsets(int fd, struct pfarg_setinfo __user *ureq, int count)
+{
+ struct pfm_context *ctx;
+ struct pfarg_setinfo *req;
+ unsigned long flags;
+ size_t sz;
+ int ret;
+
+ if (count < 0)
+ return -EINVAL;
+
+ ctx = pfm_get_ctx(fd);
+ if (ctx == NULL)
+ return -EBADF;
+
+ sz = count*sizeof(*ureq);
+
+ ret = pfm_get_args(ureq, sz, (void **)&req);
+ if (ret)
+ goto error;
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ ret = pfm_check_task_state(ctx, PFM_CMD_UNLOADED, &flags);
+ if (ret == 0)
+ ret = __pfm_delete_evtsets(ctx, req, count);
+
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ if (copy_to_user(ureq, req, sz))
+ ret = -EFAULT;
+
+ kfree(req);
+
+error:
+ pfm_put_ctx(ctx);
+
+ return ret;
+}
+
+asmlinkage long sys_pfm_create_evtsets(int fd, struct pfarg_setdesc __user *ureq, int count)
+{
+ struct pfm_context *ctx;
+ struct pfarg_setdesc *req;
+ unsigned long flags;
+ size_t sz;
+ int ret;
+
+ if (count < 0)
+ return -EINVAL;
+
+ ctx = pfm_get_ctx(fd);
+ if (ctx == NULL)
+ return -EBADF;
+
+ sz = count*sizeof(*ureq);
+
+ ret = pfm_get_args(ureq, sz, (void **)&req);
+ if (ret)
+ goto error;
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ ret = pfm_check_task_state(ctx, PFM_CMD_UNLOADED, &flags);
+ if (ret == 0)
+ ret = __pfm_create_evtsets(ctx, req, count);
+
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ if (copy_to_user(ureq, req, sz))
+ ret = -EFAULT;
+
+ kfree(req);
+
+error:
+ pfm_put_ctx(ctx);
+
+ return ret;
+}
+
+asmlinkage long sys_pfm_getinfo_evtsets(int fd, struct pfarg_setinfo __user *ureq, int count)
+{
+ struct pfm_context *ctx;
+ struct pfarg_setinfo *req;
+ unsigned long flags;
+ size_t sz;
+ int ret;
+
+ if (count < 0)
+ return -EINVAL;
+
+ ctx = pfm_get_ctx(fd);
+ if (ctx == NULL)
+ return -EBADF;
+
+ sz = count*sizeof(*ureq);
+
+ ret = pfm_get_args(ureq, sz, (void **)&req);
+ if (ret)
+ goto error;
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ ret = pfm_check_task_state(ctx, 0, &flags);
+ if (ret == 0)
+ ret = __pfm_getinfo_evtsets(ctx, req, count);
+
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ if (copy_to_user(ureq, req, sz))
+ ret = -EFAULT;
+
+ kfree(req);
+error:
+ pfm_put_ctx(ctx);
+
+ return ret;
+}
--- linux-2.6.17-rc6.orig/perfmon/perfmon_file.c 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.17-rc6/perfmon/perfmon_file.c 2006-06-12 06:52:54.000000000 -0700
@@ -0,0 +1,810 @@
+/*
+ * perfmon_file.c: perfmon2 file input/output functions
+ *
+ * This file implements the perfmon2 interface which
+ * provides access to the hardware performance counters
+ * of the host processor.
+ *
+ * The initial version of perfmon.c was written by
+ * Ganesh Venkitachalam, IBM Corp.
+ *
+ * Then it was modified for perfmon-1.x by Stephane Eranian and
+ * David Mosberger, Hewlett Packard Co.
+ *
+ * Version Perfmon-2.x is a complete rewrite of perfmon-1.x
+ * by Stephane Eranian, Hewlett Packard Co.
+ *
+ * Copyright (c) 1999-2006 Hewlett-Packard Development Company, L.P.
+ * Contributed by Stephane Eranian <[email protected]>
+ * David Mosberger-Tang <[email protected]>
+ *
+ * More information about perfmon available at:
+ * http://www.hpl.hp.com/research/linux/perfmon
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/file.h>
+#include <linux/poll.h>
+#include <linux/vfs.h>
+#include <linux/pagemap.h>
+#include <linux/mount.h>
+#include <linux/perfmon.h>
+
+#define PFMFS_MAGIC 0xa0b4d889 /* perfmon filesystem magic number */
+
+static struct file_operations pfm_file_ops;
+
+static int pfmfs_delete_dentry(struct dentry *dentry)
+{
+ return 1;
+}
+
+static struct dentry_operations pfmfs_dentry_operations = {
+ .d_delete = pfmfs_delete_dentry,
+};
+
+int pfm_is_fd(struct file *filp)
+{
+ return filp->f_op == &pfm_file_ops;
+}
+
+static union pfm_msg *pfm_get_next_msg(struct pfm_context *ctx)
+{
+ union pfm_msg *msg;
+
+ PFM_DBG("ctx=%p head=%d tail=%d",
+ ctx,
+ ctx->msgq_head,
+ ctx->msgq_tail);
+
+ if (PFM_CTXQ_EMPTY(ctx))
+ return NULL;
+
+ /*
+ * get oldest message
+ */
+ msg = ctx->msgq+ctx->msgq_head;
+
+ /*
+ * and move forward
+ */
+ ctx->msgq_head = (ctx->msgq_head+1) % PFM_MAX_MSGS;
+
+ PFM_DBG("ctx=%p head=%d tail=%d type=%d",
+ ctx,
+ ctx->msgq_head,
+ ctx->msgq_tail,
+ msg->type);
+
+ return msg;
+}
+
+static struct page *pfm_buf_map_pagefault(struct vm_area_struct *vma,
+ unsigned long address, int *type)
+{
+ void *kaddr;
+ struct pfm_context *ctx;
+ struct page *page;
+ size_t size;
+
+ ctx = vma->vm_private_data;
+ if (ctx == NULL) {
+ PFM_DBG("no ctx");
+ return NOPAGE_SIGBUS;
+ }
+ size = ctx->smpl_size;
+
+ if ( (address < (unsigned long) vma->vm_start) ||
+ (address > (unsigned long) (vma->vm_start + size)) )
+ return NOPAGE_SIGBUS;
+
+ kaddr = ctx->smpl_addr + (address - vma->vm_start);
+
+ if (type)
+ *type = VM_FAULT_MINOR;
+
+ page = vmalloc_to_page(kaddr);
+ get_page(page);
+
+ PFM_DBG("[%d] start=%p ref_count=%d",
+ current->pid,
+ kaddr, page_count(page));
+
+ return page;
+}
+
+struct vm_operations_struct pfm_buf_map_vm_ops = {
+ .nopage = pfm_buf_map_pagefault,
+};
+
+static int pfm_mmap_buffer(struct pfm_context *ctx, struct vm_area_struct *vma,
+ size_t size)
+{
+ if (ctx->smpl_addr == NULL) {
+ PFM_DBG("no sampling buffer to map");
+ return -EINVAL;
+ }
+
+ if (size > ctx->smpl_size) {
+ PFM_DBG("mmap size=%zu >= actual buf size=%zu",
+ size,
+ ctx->smpl_size);
+ return -EINVAL;
+ }
+
+ vma->vm_ops = &pfm_buf_map_vm_ops;
+ vma->vm_private_data = ctx;
+
+ return 0;
+}
+
+static int pfm_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ size_t size;
+ struct pfm_context *ctx;
+ unsigned long flags;
+ int ret;
+
+
+ ctx = file->private_data;
+ size = (vma->vm_end - vma->vm_start);
+
+ if (ctx == NULL)
+ return -EINVAL;
+
+ ret = -EINVAL;
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ if (vma->vm_flags & VM_WRITE) {
+ PFM_DBG("cannot map buffer for writing");
+ goto done;
+ }
+
+ PFM_DBG("vm_pgoff=%lu size=%zu vm_start=0x%lx",
+ vma->vm_pgoff,
+ size,
+ vma->vm_start);
+
+ if (vma->vm_pgoff == 0) {
+ ret = pfm_mmap_buffer(ctx, vma, size);
+
+ } else {
+ ret = pfm_mmap_set(ctx, vma, size);
+ }
+ /*
+ * marked the vma as special (important on the free side)
+ */
+ if (ret == 0)
+ vma->vm_flags |= VM_RESERVED;
+
+ PFM_DBG("ret=%d vma_flags=0x%lx vma_start=0x%lx vma_size=%lu",
+ ret,
+ vma->vm_flags,
+ vma->vm_start,
+ vma->vm_end-vma->vm_start);
+done:
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ return ret;
+}
+
+ssize_t __pfmk_read(struct pfm_context *ctx, union pfm_msg *msg_buf, int noblock)
+{
+ union pfm_msg *msg;
+ ssize_t ret = 0;
+ unsigned long flags;
+
+ /*
+ * we must masks interrupts to avoid a race condition
+ * with the PMU interrupt handler.
+ */
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ if(PFM_CTXQ_EMPTY(ctx) == 0)
+ goto fast_path;
+
+ ret = -EAGAIN;
+ if (noblock)
+ goto empty;
+
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ ret = wait_for_completion_interruptible(ctx->msgq_comp);
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ if(PFM_CTXQ_EMPTY(ctx))
+ goto empty;
+
+fast_path:
+
+ /*
+ * extract message from queue
+ *
+ * it is possible that the message was stolen by another thread
+ * before we could protect the context after schedule()
+ */
+ msg = pfm_get_next_msg(ctx);
+ if (unlikely(msg == NULL))
+ goto empty;
+
+ ret = sizeof(*msg);
+
+ /*
+ * we must make a local copy before we unlock
+ * to ensure that the message queue cannot fill
+ * (overwriting our message) up before
+ * we do copy_to_user() which cannot be done
+ * with interrupts masked.
+ */
+ *msg_buf = *msg;
+
+ PFM_DBG("type=%d ret=%zd", msg->type, ret);
+
+empty:
+ spin_unlock_irqrestore(&ctx->lock, flags);
+ return ret;
+}
+EXPORT_SYMBOL(__pfmk_read);
+
+ssize_t __pfm_read(struct pfm_context *ctx, union pfm_msg *msg_buf, int non_block)
+{
+ union pfm_msg *msg;
+ ssize_t ret = 0;
+ unsigned long flags;
+ DECLARE_WAITQUEUE(wait, current);
+
+ /*
+ * we must masks interrupts to avoid a race condition
+ * with the PMU interrupt handler.
+ */
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ if(PFM_CTXQ_EMPTY(ctx) == 0)
+ goto fast_path;
+retry:
+ /*
+ * check non-blocking read. we include it
+ * in the loop in case another thread modifies
+ * the propoerty of the file while the current thread
+ * is looping here
+ */
+
+ ret = -EAGAIN;
+ if(non_block)
+ goto abort_locked;
+
+ /*
+ * put ourself on the wait queue
+ */
+ add_wait_queue(&ctx->msgq_wait, &wait);
+
+ for (;;) {
+ /*
+ * check wait queue
+ */
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ PFM_DBG("head=%d tail=%d",
+ ctx->msgq_head,
+ ctx->msgq_tail);
+
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ /*
+ * wait for message
+ */
+ schedule();
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ /*
+ * check pending signals
+ */
+ ret = -ERESTARTSYS;
+ if(signal_pending(current))
+ break;
+
+ ret = 0;
+ if(PFM_CTXQ_EMPTY(ctx) == 0)
+ break;
+ }
+
+ set_current_state(TASK_RUNNING);
+
+ remove_wait_queue(&ctx->msgq_wait, &wait);
+
+ PFM_DBG("back to running ret=%zd", ret);
+
+ if (ret < 0)
+ goto abort_locked;
+
+fast_path:
+
+ /*
+ * extract message from queue
+ *
+ * it is possible that the message was stolen by another thread
+ * before we could protect the context after schedule()
+ */
+ msg = pfm_get_next_msg(ctx);
+ if (unlikely(msg == NULL))
+ goto retry;
+
+ /*
+ * we must make a local copy before we unlock
+ * to ensure that the message queue cannot fill
+ * (overwriting our message) up before
+ * we do copy_to_user() which cannot be done
+ * with interrupts masked.
+ */
+ *msg_buf = *msg;
+
+ ret = sizeof(*msg);
+
+ PFM_DBG("type=%d size=%zu", msg->type, ret);
+
+abort_locked:
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ /*
+ * ret = EAGAIN when non-blocking and nothing is
+ * in thequeue.
+ *
+ * ret = ERESTARTSYS when signal pending
+ *
+ * otherwise ret = size of message
+ */
+ return ret;
+}
+
+static ssize_t pfm_read(struct file *filp, char __user *buf, size_t size,
+ loff_t *ppos)
+{
+ struct pfm_context *ctx;
+ union pfm_msg msg_buf;
+ int non_block, ret;
+
+ ctx = filp->private_data;
+ if (ctx == NULL) {
+ PFM_ERR("no ctx for pfm_read");
+ return -EINVAL;
+ }
+
+ /*
+ * cannot extract partial messages.
+ * check even when there is no message
+ *
+ * cannot extract more than one message per call. Bytes
+ * above sizeof(msg) are ignored.
+ */
+ if (size < sizeof(msg_buf)) {
+ PFM_DBG("message is too small size=%zu must be >=%zu)",
+ size,
+ sizeof(msg_buf));
+ return -EINVAL;
+ }
+
+ non_block = filp->f_flags & O_NONBLOCK;
+
+ ret = __pfm_read(ctx, &msg_buf, non_block);
+ if (ret > 0) {
+ if(copy_to_user(buf, &msg_buf, sizeof(msg_buf)))
+ ret = -EFAULT;
+ }
+ return ret;
+}
+
+static ssize_t pfm_write(struct file *file, const char __user *ubuf,
+ size_t size, loff_t *ppos)
+{
+ PFM_DBG("pfm_write called");
+ return -EINVAL;
+}
+
+static unsigned int pfm_poll(struct file *filp, poll_table * wait)
+{
+ struct pfm_context *ctx;
+ unsigned long flags;
+ unsigned int mask = 0;
+
+ if (!pfm_is_fd(filp)) {
+ PFM_ERR("pfm_poll bad magic");
+ return 0;
+ }
+
+ ctx = filp->private_data;
+ if (ctx == NULL) {
+ PFM_ERR("pfm_poll no ctx");
+ return 0;
+ }
+
+
+ PFM_DBG("before poll_wait");
+
+ poll_wait(filp, &ctx->msgq_wait, wait);
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ if (PFM_CTXQ_EMPTY(ctx) == 0)
+ mask = POLLIN | POLLRDNORM;
+
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ PFM_DBG("after poll_wait mask=0x%x", mask);
+
+ return mask;
+}
+
+static int pfm_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ PFM_DBG("pfm_ioctl called");
+ return -EINVAL;
+}
+
+/*
+ * interrupt cannot be masked when entering this function
+ */
+static inline int __pfm_fasync(int fd, struct file *filp,
+ struct pfm_context *ctx, int on)
+{
+ int ret;
+
+ ret = fasync_helper (fd, filp, on, &ctx->async_queue);
+
+ PFM_DBG("fd=%d on=%d async_q=%p ret=%d",
+ fd,
+ on,
+ ctx->async_queue, ret);
+
+ return ret;
+}
+
+static int pfm_fasync(int fd, struct file *filp, int on)
+{
+ struct pfm_context *ctx;
+ int ret;
+
+ ctx = filp->private_data;
+ if (ctx == NULL) {
+ PFM_ERR("pfm_fasync no ctx");
+ return -EBADF;
+ }
+
+ /*
+ * we cannot mask interrupts during this call because this may
+ * may go to sleep if memory is not readily avalaible.
+ *
+ * We are protected from the context disappearing by the
+ * get_fd()/put_fd() done in caller. Serialization of this function
+ * is ensured by caller.
+ */
+ ret = __pfm_fasync(fd, filp, ctx, on);
+
+ PFM_DBG("pfm_fasync called on fd=%d on=%d async_queue=%p ret=%d",
+ fd,
+ on,
+ ctx->async_queue, ret);
+
+ return ret;
+}
+
+/*
+ * called either on explicit close() or from exit_files().
+ * Only the LAST user of the file gets to this point, i.e., it is
+ * called only ONCE.
+ *
+ * IMPORTANT: we get called ONLY when the refcnt on the file gets to zero
+ * (fput()),i.e, last task to access the file. Nobody else can access the
+ * file at this point.
+ *
+ * When called from exit_files(), the VMA has been freed because exit_mm()
+ * is executed before exit_files().
+ *
+ * When called from exit_files(), the current task is not yet ZOMBIE but we
+ * flush the PMU state to the context.
+ */
+int __pfm_close(struct pfm_context *ctx, struct file *filp)
+{
+ struct task_struct *task;
+ unsigned long flags;
+ int free_possible, can_unload;
+ int state, is_system;
+
+ free_possible = 1;
+ can_unload = 1;
+
+ spin_lock_irqsave(&ctx->lock, flags);
+
+ state = ctx->state;
+ is_system = ctx->flags.system;
+ task = ctx->task;
+
+ /*
+ * task is NULL for a system-wide context
+ */
+ if (task == NULL)
+ task = current;
+
+ PFM_DBG("ctx_state=%d is_system=%d is_current=%d",
+ state,
+ is_system,
+ task == current);
+
+ /*
+ * check if unload is needed
+ */
+ if (state == PFM_CTX_UNLOADED)
+ goto doit;
+
+ /*
+ * context is loaded/masked, we need to
+ * either force an unload or go zombie
+ */
+
+ if (is_system) {
+#ifdef CONFIG_SMP
+ /*
+ * We need to release the resource on the ORIGINAL cpu.
+ */
+ if (ctx->cpu != smp_processor_id()) {
+ /*
+ * keep context protected but unmask interrupt
+ * for IPI
+ */
+ local_irq_restore(flags);
+
+ pfm_syswide_cleanup_other_cpu(ctx);
+
+ /*
+ * restore interrupt masking
+ */
+ local_irq_save(flags);
+
+ can_unload = 0;
+ }
+#endif
+ } else if (task != current) {
+#ifdef CONFIG_SMP
+ /*
+ * switch context to zombie state
+ */
+ ctx->state = PFM_CTX_ZOMBIE;
+
+ PFM_DBG("zombie ctx for [%d]", task->pid);
+
+ if (state == PFM_CTX_MASKED && ctx->flags.block) {
+ /*
+ * force task to wake up from MASKED state
+ */
+ PFM_DBG("waking up ctx_state=%d", state);
+
+ complete(&ctx->restart_complete);
+ }
+ /*
+ * cannot free the context on the spot. deferred until
+ * the task notices the ZOMBIE state
+ */
+ free_possible = can_unload = 0;
+#endif
+ }
+ if (can_unload)
+ __pfm_unload_context(ctx, 0);
+doit:
+ /* reload state */
+ state = ctx->state;
+
+ PFM_DBG("ctx_state=%d free_possible=%d can_unload=%d",
+ state,
+ free_possible,
+ can_unload);
+
+ if (state == PFM_CTX_ZOMBIE)
+ pfm_release_session(ctx, ctx->cpu);
+
+ /*
+ * disconnect file descriptor from context must be done
+ * before we unlock.
+ */
+ if (filp)
+ filp->private_data = NULL;
+
+ /*
+ * if we free on the spot, the context is now completely unreacheable
+ * from the callers side. The monitored task side is also cut, so we
+ * can freely cut.
+ *
+ * If we have a deferred free, only the caller side is disconnected.
+ */
+ spin_unlock_irqrestore(&ctx->lock, flags);
+
+ /*
+ * return the memory used by the context
+ */
+ if (free_possible)
+ pfm_context_free(ctx);
+
+ return 0;
+}
+
+static int pfm_close(struct inode *inode, struct file *filp)
+{
+ struct pfm_context *ctx;
+
+ ctx = filp->private_data;
+ if (ctx == NULL) {
+ PFM_ERR("no ctx");
+ return -EBADF;
+ }
+ return __pfm_close(ctx, filp);
+}
+
+static int pfm_no_open(struct inode *irrelevant, struct file *dontcare)
+{
+ return -ENXIO;
+}
+
+/*
+ * pfm_flush() is called from filp_close() on every call to
+ * close(). pfm_close() is only invoked when the last user
+ * calls close(). pfm_close() is never invoked without
+ * pfm_flush() being invoked first.
+ *
+ * Partially free resources:
+ * - remove from fasync queue
+ */
+static int pfm_flush(struct file *filp)
+{
+ struct pfm_context *ctx;
+
+ ctx = filp->private_data;
+ if (ctx == NULL) {
+ PFM_ERR("pfm_flush no ctx");
+ return -EBADF;
+ }
+
+ /*
+ * remove our file from the async queue, if we use this mode.
+ * This can be done without the context being protected. We come
+ * here when the context has become unreacheable by other tasks.
+ *
+ * We may still have active monitoring at this point and we may
+ * end up in pfm_overflow_handler(). However, fasync_helper()
+ * operates with interrupts disabled and it cleans up the
+ * queue. If the PMU handler is called prior to entering
+ * fasync_helper() then it will send a signal. If it is
+ * invoked after, it will find an empty queue and no
+ * signal will be sent. In both case, we are safe
+ */
+ if (filp->f_flags & FASYNC) {
+ PFM_DBG("cleaning up async_queue=%p", ctx->async_queue);
+ __pfm_fasync (-1, filp, ctx, 0);
+ }
+ return 0;
+}
+
+static struct file_operations pfm_file_ops = {
+ .llseek = no_llseek,
+ .read = pfm_read,
+ .write = pfm_write,
+ .poll = pfm_poll,
+ .ioctl = pfm_ioctl,
+ .open = pfm_no_open, /* special open to disallow open via /proc */
+ .fasync = pfm_fasync,
+ .release = pfm_close,
+ .flush= pfm_flush,
+ .mmap = pfm_mmap
+};
+
+
+
+static struct super_block *pfmfs_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name,
+ void *data)
+{
+ return get_sb_pseudo(fs_type, "pfm:", NULL, PFMFS_MAGIC);
+}
+
+static struct file_system_type pfm_fs_type = {
+ .name = "pfmfs",
+ .get_sb = pfmfs_get_sb,
+ .kill_sb = kill_anon_super,
+};
+
+
+/*
+ * pfmfs should _never_ be mounted by userland - too much of security hassle,
+ * no real gain from having the whole whorehouse mounted. So we don't need
+ * any operations on the root directory. However, we need a non-trivial
+ * d_name - pfm: will go nicely and kill the special-casing in procfs.
+ */
+static struct vfsmount *pfmfs_mnt;
+
+int __init init_pfm_fs(void)
+{
+ int err = register_filesystem(&pfm_fs_type);
+ if (!err) {
+ pfmfs_mnt = kern_mount(&pfm_fs_type);
+ err = PTR_ERR(pfmfs_mnt);
+ if (IS_ERR(pfmfs_mnt))
+ unregister_filesystem(&pfm_fs_type);
+ else
+ err = 0;
+ }
+ return err;
+}
+
+static void __exit exit_pfm_fs(void)
+{
+ unregister_filesystem(&pfm_fs_type);
+ mntput(pfmfs_mnt);
+}
+
+int pfm_alloc_fd(struct file **cfile)
+{
+ int fd, ret = 0;
+ struct file *file = NULL;
+ struct inode * inode;
+ char name[32];
+ struct qstr this;
+
+ fd = get_unused_fd();
+ if (fd < 0)
+ return -ENFILE;
+
+ ret = -ENFILE;
+
+ file = get_empty_filp();
+ if (!file)
+ goto out;
+
+ /*
+ * allocate a new inode
+ */
+ inode = new_inode(pfmfs_mnt->mnt_sb);
+ if (!inode)
+ goto out;
+
+ PFM_DBG("new inode ino=%ld @%p", inode->i_ino, inode);
+
+ inode->i_sb = pfmfs_mnt->mnt_sb;
+ inode->i_mode = S_IFCHR|S_IRUGO;
+ inode->i_uid = current->fsuid;
+ inode->i_gid = current->fsgid;
+
+ sprintf(name, "[%lu]", inode->i_ino);
+ this.name = name;
+ this.hash = inode->i_ino;
+ this.len = strlen(name);
+
+ ret = -ENOMEM;
+
+ /*
+ * allocate a new dcache entry
+ */
+ file->f_dentry = d_alloc(pfmfs_mnt->mnt_sb->s_root, &this);
+ if (!file->f_dentry)
+ goto out;
+
+ file->f_dentry->d_op = &pfmfs_dentry_operations;
+
+ d_add(file->f_dentry, inode);
+ file->f_vfsmnt = mntget(pfmfs_mnt);
+ file->f_mapping = inode->i_mapping;
+
+ file->f_op = &pfm_file_ops;
+ file->f_mode = FMODE_READ;
+ file->f_flags = O_RDONLY;
+ file->f_pos = 0;
+
+ *cfile = file;
+
+ return fd;
+out:
+ if (file)
+ put_filp(file);
+ put_unused_fd(fd);
+ return ret;
+}
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