/*
 * lz4defs.h -- architecture specific defines
 *
 * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

/*
 * Detects 64 bits mode
 */
#if defined(CONFIG_64BIT)
#define LZ4_ARCH64 1
#else
#define LZ4_ARCH64 0
#endif

/*
 * Architecture-specific macros
 */
#define BYTE	u8
typedef struct _U16_S { u16 v; } U16_S;
typedef struct _U32_S { u32 v; } U32_S;
typedef struct _U64_S { u64 v; } U64_S;
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)

#define A16(x) (((U16_S *)(x))->v)
#define A32(x) (((U32_S *)(x))->v)
#define A64(x) (((U64_S *)(x))->v)

#define PUT4(s, d) (A32(d) = A32(s))
#define PUT8(s, d) (A64(d) = A64(s))

#define LZ4_READ_LITTLEENDIAN_16(d, s, p)	\
	(d = s - A16(p))

#define LZ4_WRITE_LITTLEENDIAN_16(p, v)	\
	do {	\
		A16(p) = v; \
		p += 2; \
	} while (0)
#else /* CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS */

#define A64(x) get_unaligned((u64 *)&(((U16_S *)(x))->v))
#define A32(x) get_unaligned((u32 *)&(((U16_S *)(x))->v))
#define A16(x) get_unaligned((u16 *)&(((U16_S *)(x))->v))

#define PUT4(s, d) \
	put_unaligned(get_unaligned((const u32 *) s), (u32 *) d)
#define PUT8(s, d) \
	put_unaligned(get_unaligned((const u64 *) s), (u64 *) d)

#define LZ4_READ_LITTLEENDIAN_16(d, s, p)	\
	(d = s - get_unaligned_le16(p))

#define LZ4_WRITE_LITTLEENDIAN_16(p, v)			\
	do {						\
		put_unaligned_le16(v, (u16 *)(p));	\
		p += 2;					\
	} while (0)
#endif

#define COPYLENGTH 8
#define ML_BITS  4
#define ML_MASK  ((1U << ML_BITS) - 1)
#define RUN_BITS (8 - ML_BITS)
#define RUN_MASK ((1U << RUN_BITS) - 1)
#define MEMORY_USAGE	14
#define MINMATCH	4
#define SKIPSTRENGTH	6
#define LASTLITERALS	5
#define MFLIMIT		(COPYLENGTH + MINMATCH)
#define MINLENGTH	(MFLIMIT + 1)
#define MAXD_LOG	16
#define MAXD		(1 << MAXD_LOG)
#define MAXD_MASK	(u32)(MAXD - 1)
#define MAX_DISTANCE	(MAXD - 1)
#define HASH_LOG	(MAXD_LOG - 1)
#define HASHTABLESIZE	(1 << HASH_LOG)
#define MAX_NB_ATTEMPTS	256
#define OPTIMAL_ML	(int)((ML_MASK-1)+MINMATCH)
#define LZ4_64KLIMIT	((1<<16) + (MFLIMIT - 1))
#define HASHLOG64K	((MEMORY_USAGE - 2) + 1)
#define HASH64KTABLESIZE	(1U << HASHLOG64K)
#define LZ4_HASH_VALUE(p)	(((A32(p)) * 2654435761U) >> \
				((MINMATCH * 8) - (MEMORY_USAGE-2)))
#define LZ4_HASH64K_VALUE(p)	(((A32(p)) * 2654435761U) >> \
				((MINMATCH * 8) - HASHLOG64K))
#define HASH_VALUE(p)		(((A32(p)) * 2654435761U) >> \
				((MINMATCH * 8) - HASH_LOG))

#if LZ4_ARCH64/* 64-bit */
#define STEPSIZE 8

#define LZ4_COPYSTEP(s, d)	\
	do {			\
		PUT8(s, d);	\
		d += 8;		\
		s += 8;		\
	} while (0)

#define LZ4_COPYPACKET(s, d)	LZ4_COPYSTEP(s, d)

#define LZ4_SECURECOPY(s, d, e)			\
	do {					\
		if (d < e) {			\
			LZ4_WILDCOPY(s, d, e);	\
		}				\
	} while (0)
#define HTYPE u32

#ifdef __BIG_ENDIAN
#define LZ4_NBCOMMONBYTES(val) (__builtin_clzll(val) >> 3)
#else
#define LZ4_NBCOMMONBYTES(val) (__builtin_ctzll(val) >> 3)
#endif

#else	/* 32-bit */
#define STEPSIZE 4

#define LZ4_COPYSTEP(s, d)	\
	do {			\
		PUT4(s, d);	\
		d += 4;		\
		s += 4;		\
	} while (0)

#define LZ4_COPYPACKET(s, d)		\
	do {				\
		LZ4_COPYSTEP(s, d);	\
		LZ4_COPYSTEP(s, d);	\
	} while (0)

#define LZ4_SECURECOPY	LZ4_WILDCOPY
#define HTYPE const u8*

#ifdef __BIG_ENDIAN
#define LZ4_NBCOMMONBYTES(val) (__builtin_clz(val) >> 3)
#else
#define LZ4_NBCOMMONBYTES(val) (__builtin_ctz(val) >> 3)
#endif

#endif

#define LZ4_WILDCOPY(s, d, e)		\
	do {				\
		LZ4_COPYPACKET(s, d);	\
	} while (d < e)

#define LZ4_BLINDCOPY(s, d, l)	\
	do {	\
		u8 *e = (d) + l;	\
		LZ4_WILDCOPY(s, d, e);	\
		d = e;	\
	} while (0)
on 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/include/acpi/acpi_drivers.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/acpi/acpi_drivers.h?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/include/acpi/acpi_drivers.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>include/acpi/acpi_drivers.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/acpi/acpi_drivers.h?id=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>2c5d9555d6d937966d79d4c6529a5f7b9206e405</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/acpi/acpi_drivers.h?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 'include/acpi/acpi_drivers.h')</div><table summary='diffstat' class='diffstat'>