3bf3710e37
The internal ttm_bo_util memcpy uses ioremap functionality, and while it probably might be possible to use it for copying in- and out of sglist represented io memory, using io_mem_reserve() / io_mem_free() callbacks, that would cause problems with fault(). Instead, implement a method mapping page-by-page using kmap_local() semantics. As an additional benefit we then avoid the occasional global TLB flushes of ioremap() and consuming ioremap space, elimination of a critical point of failure and with a slight change of semantics we could also push the memcpy out async for testing and async driver development purposes. A special linear iomem iterator is introduced internally to mimic the old ioremap behaviour for code-paths that can't immediately be ported over. This adds to the code size and should be considered a temporary solution. Looking at the code we have a lot of checks for iomap tagged pointers. Ideally we should extend the core memremap functions to also accept uncached memory and kmap_local functionality. Then we could strip a lot of code. Cc: Christian König <christian.koenig@amd.com> Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com> Reviewed-by: Christian König <christian.koenig@amd.com> Link: https://lore.kernel.org/r/20210602083818.241793-4-thomas.hellstrom@linux.intel.com
94 lines
2.9 KiB
C
94 lines
2.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 OR MIT */
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/**************************************************************************
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*
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* Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
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* All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sub license, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial portions
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* of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
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* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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* USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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**************************************************************************/
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/*
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* Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
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* Jerome Glisse
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*/
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/pgtable.h>
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#include <linux/sched.h>
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#include <linux/debugfs.h>
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#include <drm/drm_sysfs.h>
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#include <drm/ttm/ttm_caching.h>
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#include "ttm_module.h"
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/**
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* ttm_prot_from_caching - Modify the page protection according to the
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* ttm cacing mode
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* @caching: The ttm caching mode
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* @tmp: The original page protection
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*
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* Return: The modified page protection
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*/
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pgprot_t ttm_prot_from_caching(enum ttm_caching caching, pgprot_t tmp)
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{
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/* Cached mappings need no adjustment */
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if (caching == ttm_cached)
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return tmp;
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#if defined(__i386__) || defined(__x86_64__)
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if (caching == ttm_write_combined)
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tmp = pgprot_writecombine(tmp);
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else if (boot_cpu_data.x86 > 3)
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tmp = pgprot_noncached(tmp);
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#endif
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#if defined(__ia64__) || defined(__arm__) || defined(__aarch64__) || \
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defined(__powerpc__) || defined(__mips__)
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if (caching == ttm_write_combined)
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tmp = pgprot_writecombine(tmp);
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else
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tmp = pgprot_noncached(tmp);
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#endif
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#if defined(__sparc__)
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tmp = pgprot_noncached(tmp);
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#endif
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return tmp;
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}
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struct dentry *ttm_debugfs_root;
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static int __init ttm_init(void)
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{
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ttm_debugfs_root = debugfs_create_dir("ttm", NULL);
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return 0;
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}
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static void __exit ttm_exit(void)
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{
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debugfs_remove(ttm_debugfs_root);
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}
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module_init(ttm_init);
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module_exit(ttm_exit);
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MODULE_AUTHOR("Thomas Hellstrom, Jerome Glisse");
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MODULE_DESCRIPTION("TTM memory manager subsystem (for DRM device)");
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MODULE_LICENSE("GPL and additional rights");
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