linux/include/drm/drm_cache.h
Michael D Labriola 913b2cb727 drm: change func to better detect wether swiotlb is needed
This commit fixes DRM failures on Xen PV systems that were introduced in
v4.17 by the following commits:

82626363 drm: add func to get max iomem address v2
fd5fd480 drm/amdgpu: only enable swiotlb alloc when need v2
1bc3d3cc drm/radeon: only enable swiotlb path when need v2

The introduction of ->need_swiotlb to the ttm_dma_populate() conditionals
in the radeon and amdgpu device drivers causes Gnome to immediately crash
on Xen PV systems, returning the user to the login screen.  The following
kernel errors get logged:

[   28.554259] radeon_dp_aux_transfer_native: 200 callbacks suppressed
[   31.219821] radeon 0000:01:00.0: swiotlb buffer is full (sz: 2097152 bytes)
[   31.220030] [drm:radeon_gem_object_create [radeon]] *ERROR* Failed to allocate GEM object (16384000, 2, 4096, -14)
[   31.226109] radeon 0000:01:00.0: swiotlb buffer is full (sz: 2097152 bytes)
[   31.226300] [drm:radeon_gem_object_create [radeon]] *ERROR* Failed to allocate GEM object (16384000, 2, 4096, -14)
[   31.300734] gnome-shell[1935]: segfault at 88 ip 00007f39151cd904 sp 00007ffc97611ad8 error 4 in libmutter-cogl.so[7f3915178000+aa000]
[   31.300745] Code: 5f c3 0f 1f 40 00 48 8b 47 78 48 8b 40 40 ff e0 66 0f 1f 44 00 00 48 8b 47 78 48 8b 40 48 ff e0 66 0f 1f 44 00 00 48 8b 47 78 <48> 8b 80 88 00 00 00 ff e0 0f 1f 00 48 8b 47 78 48 8b 40 68 ff e0
[   38.193302] radeon_dp_aux_transfer_native: 116 callbacks suppressed
[   40.009317] radeon 0000:01:00.0: swiotlb buffer is full (sz: 2097152 bytes)
[   40.009488] [drm:radeon_gem_object_create [radeon]] *ERROR* Failed to allocate GEM object (16384000, 2, 4096, -14)
[   40.015114] radeon 0000:01:00.0: swiotlb buffer is full (sz: 2097152 bytes)
[   40.015297] [drm:radeon_gem_object_create [radeon]] *ERROR* Failed to allocate GEM object (16384000, 2, 4096, -14)
[   40.028302] gnome-shell[2431]: segfault at 2dadf40 ip 0000000002dadf40 sp 00007ffcd24ea5f8 error 15
[   40.028306] Code: 20 6e 31 00 00 00 00 00 00 00 00 37 e3 3d 2d 7f 00 00 80 f4 e6 3d 2d 7f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 c1 00 00 00 00 00 00 00 80 e1 d2 03 00 00

This commit renames drm_get_max_iomem() to drm_need_swiotlb(), adds a
xen_pv_domain() check to it, and moves the bit shifting comparison that
always follows its usage into the function (simplifying the drm driver
code).

Signed-off-by: Michael D Labriola <michael.d.labriola@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/286987/
2019-02-20 13:29:29 +01:00

73 lines
2.9 KiB
C

/**************************************************************************
*
* Copyright 2009 Red Hat Inc.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
* USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*
**************************************************************************/
/*
* Authors:
* Dave Airlie <airlied@redhat.com>
*/
#ifndef _DRM_CACHE_H_
#define _DRM_CACHE_H_
#include <linux/scatterlist.h>
void drm_clflush_pages(struct page *pages[], unsigned long num_pages);
void drm_clflush_sg(struct sg_table *st);
void drm_clflush_virt_range(void *addr, unsigned long length);
bool drm_need_swiotlb(int dma_bits);
static inline bool drm_arch_can_wc_memory(void)
{
#if defined(CONFIG_PPC) && !defined(CONFIG_NOT_COHERENT_CACHE)
return false;
#elif defined(CONFIG_MIPS) && defined(CONFIG_CPU_LOONGSON3)
return false;
#elif defined(CONFIG_ARM) || defined(CONFIG_ARM64)
/*
* The DRM driver stack is designed to work with cache coherent devices
* only, but permits an optimization to be enabled in some cases, where
* for some buffers, both the CPU and the GPU use uncached mappings,
* removing the need for DMA snooping and allocation in the CPU caches.
*
* The use of uncached GPU mappings relies on the correct implementation
* of the PCIe NoSnoop TLP attribute by the platform, otherwise the GPU
* will use cached mappings nonetheless. On x86 platforms, this does not
* seem to matter, as uncached CPU mappings will snoop the caches in any
* case. However, on ARM and arm64, enabling this optimization on a
* platform where NoSnoop is ignored results in loss of coherency, which
* breaks correct operation of the device. Since we have no way of
* detecting whether NoSnoop works or not, just disable this
* optimization entirely for ARM and arm64.
*/
return false;
#else
return true;
#endif
}
#endif