Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 220 insertions, 0 deletions

diff --git a/drivers/char/uv_mmtimer.c b/drivers/char/uv_mmtimer.c
new file mode 100644
index 000000000..956ebe208
--- /dev/null
+++ b/drivers/char/uv_mmtimer.c
@@ -0,0 +1,220 @@
+/*
+ * Timer device implementation for SGI UV platform.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 2009 Silicon Graphics, Inc.  All rights reserved.
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/ioctl.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/mmtimer.h>
+#include <linux/miscdevice.h>
+#include <linux/posix-timers.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/math64.h>
+
+#include <asm/genapic.h>
+#include <asm/uv/uv_hub.h>
+#include <asm/uv/bios.h>
+#include <asm/uv/uv.h>
+
+MODULE_AUTHOR("Dimitri Sivanich <sivanich@sgi.com>");
+MODULE_DESCRIPTION("SGI UV Memory Mapped RTC Timer");
+MODULE_LICENSE("GPL");
+
+/* name of the device, usually in /dev */
+#define UV_MMTIMER_NAME "mmtimer"
+#define UV_MMTIMER_DESC "SGI UV Memory Mapped RTC Timer"
+#define UV_MMTIMER_VERSION "1.0"
+
+static long uv_mmtimer_ioctl(struct file *file, unsigned int cmd,
+						unsigned long arg);
+static int uv_mmtimer_mmap(struct file *file, struct vm_area_struct *vma);
+
+/*
+ * Period in femtoseconds (10^-15 s)
+ */
+static unsigned long uv_mmtimer_femtoperiod;
+
+static const struct file_operations uv_mmtimer_fops = {
+	.owner = THIS_MODULE,
+	.mmap =	uv_mmtimer_mmap,
+	.unlocked_ioctl = uv_mmtimer_ioctl,
+	.llseek = noop_llseek,
+};
+
+/**
+ * uv_mmtimer_ioctl - ioctl interface for /dev/uv_mmtimer
+ * @file: file structure for the device
+ * @cmd: command to execute
+ * @arg: optional argument to command
+ *
+ * Executes the command specified by @cmd.  Returns 0 for success, < 0 for
+ * failure.
+ *
+ * Valid commands:
+ *
+ * %MMTIMER_GETOFFSET - Should return the offset (relative to the start
+ * of the page where the registers are mapped) for the counter in question.
+ *
+ * %MMTIMER_GETRES - Returns the resolution of the clock in femto (10^-15)
+ * seconds
+ *
+ * %MMTIMER_GETFREQ - Copies the frequency of the clock in Hz to the address
+ * specified by @arg
+ *
+ * %MMTIMER_GETBITS - Returns the number of bits in the clock's counter
+ *
+ * %MMTIMER_MMAPAVAIL - Returns 1 if registers can be mmap'd into userspace
+ *
+ * %MMTIMER_GETCOUNTER - Gets the current value in the counter and places it
+ * in the address specified by @arg.
+ */
+static long uv_mmtimer_ioctl(struct file *file, unsigned int cmd,
+						unsigned long arg)
+{
+	int ret = 0;
+
+	switch (cmd) {
+	case MMTIMER_GETOFFSET:	/* offset of the counter */
+		/*
+		 * Starting with HUB rev 2.0, the UV RTC register is
+		 * replicated across all cachelines of it's own page.
+		 * This allows faster simultaneous reads from a given socket.
+		 *
+		 * The offset returned is in 64 bit units.
+		 */
+		if (uv_get_min_hub_revision_id() == 1)
+			ret = 0;
+		else
+			ret = ((uv_blade_processor_id() * L1_CACHE_BYTES) %
+					PAGE_SIZE) / 8;
+		break;
+
+	case MMTIMER_GETRES: /* resolution of the clock in 10^-15 s */
+		if (copy_to_user((unsigned long __user *)arg,
+				&uv_mmtimer_femtoperiod, sizeof(unsigned long)))
+			ret = -EFAULT;
+		break;
+
+	case MMTIMER_GETFREQ: /* frequency in Hz */
+		if (copy_to_user((unsigned long __user *)arg,
+				&sn_rtc_cycles_per_second,
+				sizeof(unsigned long)))
+			ret = -EFAULT;
+		break;
+
+	case MMTIMER_GETBITS: /* number of bits in the clock */
+		ret = hweight64(UVH_RTC_REAL_TIME_CLOCK_MASK);
+		break;
+
+	case MMTIMER_MMAPAVAIL:
+		ret = 1;
+		break;
+
+	case MMTIMER_GETCOUNTER:
+		if (copy_to_user((unsigned long __user *)arg,
+				(unsigned long *)uv_local_mmr_address(UVH_RTC),
+				sizeof(unsigned long)))
+			ret = -EFAULT;
+		break;
+	default:
+		ret = -ENOTTY;
+		break;
+	}
+	return ret;
+}
+
+/**
+ * uv_mmtimer_mmap - maps the clock's registers into userspace
+ * @file: file structure for the device
+ * @vma: VMA to map the registers into
+ *
+ * Calls remap_pfn_range() to map the clock's registers into
+ * the calling process' address space.
+ */
+static int uv_mmtimer_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	unsigned long uv_mmtimer_addr;
+
+	if (vma->vm_end - vma->vm_start != PAGE_SIZE)
+		return -EINVAL;
+
+	if (vma->vm_flags & VM_WRITE)
+		return -EPERM;
+
+	if (PAGE_SIZE > (1 << 16))
+		return -ENOSYS;
+
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+	uv_mmtimer_addr = UV_LOCAL_MMR_BASE | UVH_RTC;
+	uv_mmtimer_addr &= ~(PAGE_SIZE - 1);
+	uv_mmtimer_addr &= 0xfffffffffffffffUL;
+
+	if (remap_pfn_range(vma, vma->vm_start, uv_mmtimer_addr >> PAGE_SHIFT,
+					PAGE_SIZE, vma->vm_page_prot)) {
+		printk(KERN_ERR "remap_pfn_range failed in uv_mmtimer_mmap\n");
+		return -EAGAIN;
+	}
+
+	return 0;
+}
+
+static struct miscdevice uv_mmtimer_miscdev = {
+	MISC_DYNAMIC_MINOR,
+	UV_MMTIMER_NAME,
+	&uv_mmtimer_fops
+};
+
+
+/**
+ * uv_mmtimer_init - device initialization routine
+ *
+ * Does initial setup for the uv_mmtimer device.
+ */
+static int __init uv_mmtimer_init(void)
+{
+	if (!is_uv_system()) {
+		printk(KERN_ERR "%s: Hardware unsupported\n", UV_MMTIMER_NAME);
+		return -1;
+	}
+
+	/*
+	 * Sanity check the cycles/sec variable
+	 */
+	if (sn_rtc_cycles_per_second < 100000) {
+		printk(KERN_ERR "%s: unable to determine clock frequency\n",
+		       UV_MMTIMER_NAME);
+		return -1;
+	}
+
+	uv_mmtimer_femtoperiod = ((unsigned long)1E15 +
+				sn_rtc_cycles_per_second / 2) /
+				sn_rtc_cycles_per_second;
+
+	if (misc_register(&uv_mmtimer_miscdev)) {
+		printk(KERN_ERR "%s: failed to register device\n",
+		       UV_MMTIMER_NAME);
+		return -1;
+	}
+
+	printk(KERN_INFO "%s: v%s, %ld MHz\n", UV_MMTIMER_DESC,
+		UV_MMTIMER_VERSION,
+		sn_rtc_cycles_per_second/(unsigned long)1E6);
+
+	return 0;
+}
+
+module_init(uv_mmtimer_init);