cregit-Linux how code gets into the kernel

Release 4.17 drivers/gpu/drm/vmwgfx/vmwgfx_blit.c

/**************************************************************************
 *
 * Copyright © 2017 VMware, Inc., Palo Alto, CA., USA
 * 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.
 *
 **************************************************************************/

#include "vmwgfx_drv.h"

/*
 * Template that implements find_first_diff() for a generic
 * unsigned integer type. @size and return value are in bytes.
 */

#define VMW_FIND_FIRST_DIFF(_type)			 \
static size_t vmw_find_first_diff_ ## _type              \
        (const _type * dst, const _type * src, size_t size)\
{                                                        \
        size_t i;                                        \
                                                         \
        for (i = 0; i < size; i += sizeof(_type)) {      \
                if (*dst++ != *src++)                    \
                        break;                           \
        }                                                \
                                                         \
        return i;                                        \
}


/*
 * Template that implements find_last_diff() for a generic
 * unsigned integer type. Pointers point to the item following the
 * *end* of the area to be examined. @size and return value are in
 * bytes.
 */

#define VMW_FIND_LAST_DIFF(_type)					\
static ssize_t vmw_find_last_diff_ ## _type(                            \
        const _type * dst, const _type * src, size_t size)              \
{                                                                       \
        while (size) {                                                  \
                if (*--dst != *--src)                                   \
                        break;                                          \
                                                                        \
                size -= sizeof(_type);                                  \
        }                                                               \
        return size;                                                    \
}


/*
 * Instantiate find diff functions for relevant unsigned integer sizes,
 * assuming that wider integers are faster (including aligning) up to the
 * architecture native width, which is assumed to be 32 bit unless
 * CONFIG_64BIT is defined.
 */
VMW_FIND_FIRST_DIFF(u8);
VMW_FIND_LAST_DIFF(u8);

VMW_FIND_FIRST_DIFF(u16);
VMW_FIND_LAST_DIFF(u16);

VMW_FIND_FIRST_DIFF(u32);
VMW_FIND_LAST_DIFF(u32);

#ifdef CONFIG_64BIT
VMW_FIND_FIRST_DIFF(u64);
VMW_FIND_LAST_DIFF(u64);
#endif


/* We use size aligned copies. This computes (addr - align(addr)) */

#define SPILL(_var, _type) ((unsigned long) _var & (sizeof(_type) - 1))


/*
 * Template to compute find_first_diff() for a certain integer type
 * including a head copy for alignment, and adjustment of parameters
 * for tail find or increased resolution find using an unsigned integer find
 * of smaller width. If finding is complete, and resolution is sufficient,
 * the macro executes a return statement. Otherwise it falls through.
 */

#define VMW_TRY_FIND_FIRST_DIFF(_type)					\
do {                                                                    \
        unsigned int spill = SPILL(dst, _type);                         \
        size_t diff_offs;                                               \
                                                                        \
        if (spill && spill == SPILL(src, _type) &&                      \
            sizeof(_type) - spill <= size) {                            \
                spill = sizeof(_type) - spill;                          \
                diff_offs = vmw_find_first_diff_u8(dst, src, spill);    \
                if (diff_offs < spill)                                  \
                        return round_down(offset + diff_offs, granularity); \
                                                                        \
                dst += spill;                                           \
                src += spill;                                           \
                size -= spill;                                          \
                offset += spill;                                        \
                spill = 0;                                              \
        }                                                               \
        if (!spill && !SPILL(src, _type)) {                             \
                size_t to_copy = size &  ~(sizeof(_type) - 1);          \
                                                                        \
                diff_offs = vmw_find_first_diff_ ## _type               \
                        ((_type *) dst, (_type *) src, to_copy);        \
                if (diff_offs >= size || granularity == sizeof(_type))  \
                        return (offset + diff_offs);                    \
                                                                        \
                dst += diff_offs;                                       \
                src += diff_offs;                                       \
                size -= diff_offs;                                      \
                offset += diff_offs;                                    \
        }                                                               \
} while (0)								\


/**
 * vmw_find_first_diff - find the first difference between dst and src
 *
 * @dst: The destination address
 * @src: The source address
 * @size: Number of bytes to compare
 * @granularity: The granularity needed for the return value in bytes.
 * return: The offset from find start where the first difference was
 * encountered in bytes. If no difference was found, the function returns
 * a value >= @size.
 */

static size_t vmw_find_first_diff(const u8 *dst, const u8 *src, size_t size, size_t granularity) { size_t offset = 0; /* * Try finding with large integers if alignment allows, or we can * fix it. Fall through if we need better resolution or alignment * was bad. */ #ifdef CONFIG_64BIT VMW_TRY_FIND_FIRST_DIFF(u64); #endif VMW_TRY_FIND_FIRST_DIFF(u32); VMW_TRY_FIND_FIRST_DIFF(u16); return round_down(offset + vmw_find_first_diff_u8(dst, src, size), granularity); }

Contributors

PersonTokensPropCommitsCommitProp
Thomas Hellstrom65100.00%1100.00%
Total65100.00%1100.00%

/* * Template to compute find_last_diff() for a certain integer type * including a tail copy for alignment, and adjustment of parameters * for head find or increased resolution find using an unsigned integer find * of smaller width. If finding is complete, and resolution is sufficient, * the macro executes a return statement. Otherwise it falls through. */ #define VMW_TRY_FIND_LAST_DIFF(_type) \ do { \ unsigned int spill = SPILL(dst, _type); \ ssize_t location; \ ssize_t diff_offs; \ \ if (spill && spill <= size && spill == SPILL(src, _type)) { \ diff_offs = vmw_find_last_diff_u8(dst, src, spill); \ if (diff_offs) { \ location = size - spill + diff_offs - 1; \ return round_down(location, granularity); \ } \ \ dst -= spill; \ src -= spill; \ size -= spill; \ spill = 0; \ } \ if (!spill && !SPILL(src, _type)) { \ size_t to_copy = round_down(size, sizeof(_type)); \ \ diff_offs = vmw_find_last_diff_ ## _type \ ((_type *) dst, (_type *) src, to_copy); \ location = size - to_copy + diff_offs - sizeof(_type); \ if (location < 0 || granularity == sizeof(_type)) \ return location; \ \ dst -= to_copy - diff_offs; \ src -= to_copy - diff_offs; \ size -= to_copy - diff_offs; \ } \ } while (0) /** * vmw_find_last_diff - find the last difference between dst and src * * @dst: The destination address * @src: The source address * @size: Number of bytes to compare * @granularity: The granularity needed for the return value in bytes. * return: The offset from find start where the last difference was * encountered in bytes, or a negative value if no difference was found. */
static ssize_t vmw_find_last_diff(const u8 *dst, const u8 *src, size_t size, size_t granularity) { dst += size; src += size; #ifdef CONFIG_64BIT VMW_TRY_FIND_LAST_DIFF(u64); #endif VMW_TRY_FIND_LAST_DIFF(u32); VMW_TRY_FIND_LAST_DIFF(u16); return round_down(vmw_find_last_diff_u8(dst, src, size) - 1, granularity); }

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Thomas Hellstrom67100.00%1100.00%
Total67100.00%1100.00%

/** * vmw_memcpy - A wrapper around kernel memcpy with allowing to plug it into a * struct vmw_diff_cpy. * * @diff: The struct vmw_diff_cpy closure argument (unused). * @dest: The copy destination. * @src: The copy source. * @n: Number of bytes to copy. */
void vmw_memcpy(struct vmw_diff_cpy *diff, u8 *dest, const u8 *src, size_t n) { memcpy(dest, src, n); }

Contributors

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Thomas Hellstrom31100.00%1100.00%
Total31100.00%1100.00%

/** * vmw_adjust_rect - Adjust rectangle coordinates for newly found difference * * @diff: The struct vmw_diff_cpy used to track the modified bounding box. * @diff_offs: The offset from @diff->line_offset where the difference was * found. */
static void vmw_adjust_rect(struct vmw_diff_cpy *diff, size_t diff_offs) { size_t offs = (diff_offs + diff->line_offset) / diff->cpp; struct drm_rect *rect = &diff->rect; rect->x1 = min_t(int, rect->x1, offs); rect->x2 = max_t(int, rect->x2, offs + 1); rect->y1 = min_t(int, rect->y1, diff->line); rect->y2 = max_t(int, rect->y2, diff->line + 1); }

Contributors

PersonTokensPropCommitsCommitProp
Thomas Hellstrom107100.00%1100.00%
Total107100.00%1100.00%

/** * vmw_diff_memcpy - memcpy that creates a bounding box of modified content. * * @diff: The struct vmw_diff_cpy used to track the modified bounding box. * @dest: The copy destination. * @src: The copy source. * @n: Number of bytes to copy. * * In order to correctly track the modified content, the field @diff->line must * be pre-loaded with the current line number, the field @diff->line_offset must * be pre-loaded with the line offset in bytes where the copy starts, and * finally the field @diff->cpp need to be preloaded with the number of bytes * per unit in the horizontal direction of the area we're examining. * Typically bytes per pixel. * This is needed to know the needed granularity of the difference computing * operations. A higher cpp generally leads to faster execution at the cost of * bounding box width precision. */
void vmw_diff_memcpy(struct vmw_diff_cpy *diff, u8 *dest, const u8 *src, size_t n) { ssize_t csize, byte_len; if (WARN_ON_ONCE(round_down(n, diff->cpp) != n)) return; /* TODO: Possibly use a single vmw_find_first_diff per line? */ csize = vmw_find_first_diff(dest, src, n, diff->cpp); if (csize < n) { vmw_adjust_rect(diff, csize); byte_len = diff->cpp; /* * Starting from where first difference was found, find * location of last difference, and then copy. */ diff->line_offset += csize; dest += csize; src += csize; n -= csize; csize = vmw_find_last_diff(dest, src, n, diff->cpp); if (csize >= 0) { byte_len += csize; vmw_adjust_rect(diff, csize); } memcpy(dest, src, byte_len); } diff->line_offset += n; }

Contributors

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Thomas Hellstrom149100.00%1100.00%
Total149100.00%1100.00%

/** * struct vmw_bo_blit_line_data - Convenience argument to vmw_bo_cpu_blit_line * * @mapped_dst: Already mapped destination page index in @dst_pages. * @dst_addr: Kernel virtual address of mapped destination page. * @dst_pages: Array of destination bo pages. * @dst_num_pages: Number of destination bo pages. * @dst_prot: Destination bo page protection. * @mapped_src: Already mapped source page index in @dst_pages. * @src_addr: Kernel virtual address of mapped source page. * @src_pages: Array of source bo pages. * @src_num_pages: Number of source bo pages. * @src_prot: Source bo page protection. * @diff: Struct vmw_diff_cpy, in the end forwarded to the memcpy routine. */ struct vmw_bo_blit_line_data { u32 mapped_dst; u8 *dst_addr; struct page **dst_pages; u32 dst_num_pages; pgprot_t dst_prot; u32 mapped_src; u8 *src_addr; struct page **src_pages; u32 src_num_pages; pgprot_t src_prot; struct vmw_diff_cpy *diff; }; /** * vmw_bo_cpu_blit_line - Blit part of a line from one bo to another. * * @d: Blit data as described above. * @dst_offset: Destination copy start offset from start of bo. * @src_offset: Source copy start offset from start of bo. * @bytes_to_copy: Number of bytes to copy in this line. */
static int vmw_bo_cpu_blit_line(struct vmw_bo_blit_line_data *d, u32 dst_offset, u32 src_offset, u32 bytes_to_copy) { struct vmw_diff_cpy *diff = d->diff; while (bytes_to_copy) { u32 copy_size = bytes_to_copy; u32 dst_page = dst_offset >> PAGE_SHIFT; u32 src_page = src_offset >> PAGE_SHIFT; u32 dst_page_offset = dst_offset & ~PAGE_MASK; u32 src_page_offset = src_offset & ~PAGE_MASK; bool unmap_dst = d->dst_addr && dst_page != d->mapped_dst; bool unmap_src = d->src_addr && (src_page != d->mapped_src || unmap_dst); copy_size = min_t(u32, copy_size, PAGE_SIZE - dst_page_offset); copy_size = min_t(u32, copy_size, PAGE_SIZE - src_page_offset); if (unmap_src) { ttm_kunmap_atomic_prot(d->src_addr, d->src_prot); d->src_addr = NULL; } if (unmap_dst) { ttm_kunmap_atomic_prot(d->dst_addr, d->dst_prot); d->dst_addr = NULL; } if (!d->dst_addr) { if (WARN_ON_ONCE(dst_page >= d->dst_num_pages)) return -EINVAL; d->dst_addr = ttm_kmap_atomic_prot(d->dst_pages[dst_page], d->dst_prot); if (!d->dst_addr) return -ENOMEM; d->mapped_dst = dst_page; } if (!d->src_addr) { if (WARN_ON_ONCE(src_page >= d->src_num_pages)) return -EINVAL; d->src_addr = ttm_kmap_atomic_prot(d->src_pages[src_page], d->src_prot); if (!d->src_addr) return -ENOMEM; d->mapped_src = src_page; } diff->do_cpy(diff, d->dst_addr + dst_page_offset, d->src_addr + src_page_offset, copy_size); bytes_to_copy -= copy_size; dst_offset += copy_size; src_offset += copy_size; } return 0; }

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Thomas Hellstrom326100.00%1100.00%
Total326100.00%1100.00%

/** * ttm_bo_cpu_blit - in-kernel cpu blit. * * @dst: Destination buffer object. * @dst_offset: Destination offset of blit start in bytes. * @dst_stride: Destination stride in bytes. * @src: Source buffer object. * @src_offset: Source offset of blit start in bytes. * @src_stride: Source stride in bytes. * @w: Width of blit. * @h: Height of blit. * return: Zero on success. Negative error value on failure. Will print out * kernel warnings on caller bugs. * * Performs a CPU blit from one buffer object to another avoiding a full * bo vmap which may exhaust- or fragment vmalloc space. * On supported architectures (x86), we're using kmap_atomic which avoids * cross-processor TLB- and cache flushes and may, on non-HIGHMEM systems * reference already set-up mappings. * * Neither of the buffer objects may be placed in PCI memory * (Fixed memory in TTM terminology) when using this function. */
int vmw_bo_cpu_blit(struct ttm_buffer_object *dst, u32 dst_offset, u32 dst_stride, struct ttm_buffer_object *src, u32 src_offset, u32 src_stride, u32 w, u32 h, struct vmw_diff_cpy *diff) { struct ttm_operation_ctx ctx = { .interruptible = false, .no_wait_gpu = false }; u32 j, initial_line = dst_offset / dst_stride; struct vmw_bo_blit_line_data d; int ret = 0; /* Buffer objects need to be either pinned or reserved: */ if (!(dst->mem.placement & TTM_PL_FLAG_NO_EVICT)) lockdep_assert_held(&dst->resv->lock.base); if (!(src->mem.placement & TTM_PL_FLAG_NO_EVICT)) lockdep_assert_held(&src->resv->lock.base); if (dst->ttm->state == tt_unpopulated) { ret = dst->ttm->bdev->driver->ttm_tt_populate(dst->ttm, &ctx); if (ret) return ret; } if (src->ttm->state == tt_unpopulated) { ret = src->ttm->bdev->driver->ttm_tt_populate(src->ttm, &ctx); if (ret) return ret; } d.mapped_dst = 0; d.mapped_src = 0; d.dst_addr = NULL; d.src_addr = NULL; d.dst_pages = dst->ttm->pages; d.src_pages = src->ttm->pages; d.dst_num_pages = dst->num_pages; d.src_num_pages = src->num_pages; d.dst_prot = ttm_io_prot(dst->mem.placement, PAGE_KERNEL); d.src_prot = ttm_io_prot(src->mem.placement, PAGE_KERNEL); d.diff = diff; for (j = 0; j < h; ++j) { diff->line = j + initial_line; diff->line_offset = dst_offset % dst_stride; ret = vmw_bo_cpu_blit_line(&d, dst_offset, src_offset, w); if (ret) goto out; dst_offset += dst_stride; src_offset += src_stride; } out: if (d.src_addr) ttm_kunmap_atomic_prot(d.src_addr, d.src_prot); if (d.dst_addr) ttm_kunmap_atomic_prot(d.dst_addr, d.dst_prot); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Thomas Hellstrom396100.00%1100.00%
Total396100.00%1100.00%


Overall Contributors

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Thomas Hellstrom1294100.00%1100.00%
Total1294100.00%1100.00%
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