/*
 *  Profiling infrastructure declarations.
 *
 *  This file is based on gcc-internal definitions. Data structures are
 *  defined to be compatible with gcc counterparts. For a better
 *  understanding, refer to gcc source: gcc/gcov-io.h.
 *
 *    Copyright IBM Corp. 2009
 *    Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
 *
 *    Uses gcc-internal data definitions.
 */

#ifndef GCOV_H
#define GCOV_H GCOV_H

#include <linux/types.h>

/*
 * Profiling data types used for gcc 3.4 and above - these are defined by
 * gcc and need to be kept as close to the original definition as possible to
 * remain compatible.
 */
#define GCOV_DATA_MAGIC		((unsigned int) 0x67636461)
#define GCOV_TAG_FUNCTION	((unsigned int) 0x01000000)
#define GCOV_TAG_COUNTER_BASE	((unsigned int) 0x01a10000)
#define GCOV_TAG_FOR_COUNTER(count)					\
	(GCOV_TAG_COUNTER_BASE + ((unsigned int) (count) << 17))

#if BITS_PER_LONG >= 64
typedef long gcov_type;
#else
typedef long long gcov_type;
#endif

/* Opaque gcov_info. The gcov structures can change as for example in gcc 4.7 so
 * we cannot use full definition here and they need to be placed in gcc specific
 * implementation of gcov. This also means no direct access to the members in
 * generic code and usage of the interface below.*/
struct gcov_info;

/* Interface to access gcov_info data  */
const char *gcov_info_filename(struct gcov_info *info);
unsigned int gcov_info_version(struct gcov_info *info);
struct gcov_info *gcov_info_next(struct gcov_info *info);
void gcov_info_link(struct gcov_info *info);
void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info);

/* Base interface. */
enum gcov_action {
	GCOV_ADD,
	GCOV_REMOVE,
};

void gcov_event(enum gcov_action action, struct gcov_info *info);
void gcov_enable_events(void);

/* Iterator control. */
struct seq_file;
struct gcov_iterator;

struct gcov_iterator *gcov_iter_new(struct gcov_info *info);
void gcov_iter_free(struct gcov_iterator *iter);
void gcov_iter_start(struct gcov_iterator *iter);
int gcov_iter_next(struct gcov_iterator *iter);
int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq);
struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter);

/* gcov_info control. */
void gcov_info_reset(struct gcov_info *info);
int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2);
void gcov_info_add(struct gcov_info *dest, struct gcov_info *source);
struct gcov_info *gcov_info_dup(struct gcov_info *info);
void gcov_info_free(struct gcov_info *info);

struct gcov_link {
	enum {
		OBJ_TREE,
		SRC_TREE,
	} dir;
	const char *ext;
};
extern const struct gcov_link gcov_link[];

#endif /* GCOV_H */
h'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/sound?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>sound</a>/<a href='/cgit.cgi/linux/net-next.git/commit/sound/soc?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>soc</a>/<a href='/cgit.cgi/linux/net-next.git/commit/sound/soc/atmel?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>atmel</a>/<a href='/cgit.cgi/linux/net-next.git/commit/sound/soc/atmel/atmel_wm8904.c?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>atmel_wm8904.c</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='39cb2c9a316e77f6dfba96c543e55b6672d5a37e'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-29 13:50:06 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-29 13:50:06 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/soc/atmel/atmel_wm8904.c?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e</a> (<a href='/cgit.cgi/linux/net-next.git/patch/sound/soc/atmel/atmel_wm8904.c?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>98fe974ee4e20121253de7f61fc8d01bdb3821c1</a> /<a href='/cgit.cgi/linux/net-next.git/tree/sound/soc/atmel/atmel_wm8904.c?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>sound/soc/atmel/atmel_wm8904.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/soc/atmel/atmel_wm8904.c?id=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>2c5d9555d6d937966d79d4c6529a5f7b9206e405</a> (<a href='/cgit.cgi/linux/net-next.git/diff/sound/soc/atmel/atmel_wm8904.c?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e&amp;id2=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>diff</a>)</td></tr></table>
<div class='commit-subject'>drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()</div><div class='commit-msg'>I've seen this trigger twice now, where the i915_gem_object_to_ggtt()
call in intel_unpin_fb_obj() returns NULL, resulting in an oops
immediately afterwards as the (inlined) call to i915_vma_unpin_fence()
tries to dereference it.

It seems to be some race condition where the object is going away at
shutdown time, since both times happened when shutting down the X
server.  The call chains were different:

 - VT ioctl(KDSETMODE, KD_TEXT):

    intel_cleanup_plane_fb+0x5b/0xa0 [i915]
    drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper]
    intel_atomic_commit_tail+0x749/0xfe0 [i915]
    intel_atomic_commit+0x3cb/0x4f0 [i915]
    drm_atomic_commit+0x4b/0x50 [drm]
    restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper]
    drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper]
    drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper]
    intel_fbdev_set_par+0x18/0x70 [i915]
    fb_set_var+0x236/0x460
    fbcon_blank+0x30f/0x350
    do_unblank_screen+0xd2/0x1a0
    vt_ioctl+0x507/0x12a0
    tty_ioctl+0x355/0xc30
    do_vfs_ioctl+0xa3/0x5e0
    SyS_ioctl+0x79/0x90
    entry_SYSCALL_64_fastpath+0x13/0x94

 - i915 unpin_work workqueue:

    intel_unpin_work_fn+0x58/0x140 [i915]
    process_one_work+0x1f1/0x480
    worker_thread+0x48/0x4d0
    kthread+0x101/0x140

and this patch purely papers over the issue by adding a NULL pointer
check and a WARN_ON_ONCE() to avoid the oops that would then generally
make the machine unresponsive.

Other callers of i915_gem_object_to_ggtt() seem to also check for the
returned pointer being NULL and warn about it, so this clearly has
happened before in other places.

[ Reported it originally to the i915 developers on Jan 8, applying the
  ugly workaround on my own now after triggering the problem for the
  second time with no feedback.

  This is likely to be the same bug reported as

     https://bugs.freedesktop.org/show_bug.cgi?id=98829
     https://bugs.freedesktop.org/show_bug.cgi?id=99134

  which has a patch for the underlying problem, but it hasn't gotten to
  me, so I'm applying the workaround. ]

Cc: Daniel Vetter &lt;daniel.vetter@intel.com&gt;
Cc: Jani Nikula &lt;jani.nikula@linux.intel.com&gt;
Cc: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Maarten Lankhorst &lt;maarten.lankhorst@linux.intel.com&gt;
Cc: Tvrtko Ursulin &lt;tvrtko.ursulin@intel.com&gt;
Cc: Imre Deak &lt;imre.deak@intel.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>Diffstat</a> (limited to 'sound/soc/atmel/atmel_wm8904.c')</div><table summary='diffstat' class='diffstat'>