[Intel-gfx] [PATCH] igt/gem_tiled_wc: Exercise wc mmaps with swizzling

Daniel Vetter daniel at ffwll.ch
Tue Nov 4 10:43:23 CET 2014


On Tue, Nov 04, 2014 at 07:35:24AM +0000, Chris Wilson wrote:
> This exercises both the wc mmappings and the extended get_tiling ioctl.
> Userspace cannot handle bit17 swizzling through wc mmaps (because bit17
> requires swizzling based on the actual physical address of the page -
> which is unknown to userspace) and so we need an extended get_tiling
> ioctl to report the actual as well as the logical swizzling on an
> object. We then check that the contents of the object are tiled and
> swizzled correctly when viewed through a wc mmap.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  tests/.gitignore       |   1 +
>  tests/Makefile.sources |   1 +
>  tests/gem_tiled_wc.c   | 241 +++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 243 insertions(+)
>  create mode 100644 tests/gem_tiled_wc.c
> 
> diff --git a/tests/.gitignore b/tests/.gitignore
> index 6c485f0..7023ede 100644
> --- a/tests/.gitignore
> +++ b/tests/.gitignore
> @@ -100,6 +100,7 @@ gem_tiled_partial_pwrite_pread
>  gem_tiled_pread
>  gem_tiled_pread_pwrite
>  gem_tiled_swapping
> +gem_tiled_wc
>  gem_tiling_max_stride
>  gem_unfence_active_buffers
>  gem_unref_active_buffers
> diff --git a/tests/Makefile.sources b/tests/Makefile.sources
> index 6e5458a..d4a203c 100644
> --- a/tests/Makefile.sources
> +++ b/tests/Makefile.sources
> @@ -133,6 +133,7 @@ TESTS_progs = \
>  	gem_tiled_pread \
>  	gem_tiled_pread_pwrite \
>  	gem_tiled_swapping \
> +	gem_tiled_wc \
>  	gem_tiling_max_stride \
>  	gem_unfence_active_buffers \
>  	gem_unref_active_buffers \
> diff --git a/tests/gem_tiled_wc.c b/tests/gem_tiled_wc.c
> new file mode 100644
> index 0000000..ad09bc9
> --- /dev/null
> +++ b/tests/gem_tiled_wc.c
> @@ -0,0 +1,241 @@
> +/*
> + * Copyright © 2009 Intel Corporation
> + *
> + * 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, sublicense,
> + * 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 NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS 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:
> + *    Eric Anholt <eric at anholt.net>
> + *
> + */
> +
> +/** @file gem_tiled_pread.c
> + *
> + * This is a test of pread's behavior on tiled objects with respect to the
> + * reported swizzling value.
> + *
> + * The goal is to exercise the slow_bit17_copy path for reading on bit17
> + * machines, but will also be useful for catching swizzling value bugs on
> + * other systems.
> + */

I guess this should be update, other Thomas Wood will put a bogus
description in ;-)

> +
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <fcntl.h>
> +#include <inttypes.h>
> +#include <errno.h>
> +#include <sys/stat.h>
> +#include <sys/time.h>
> +#include <sys/ioctl.h>
> +#include "drm.h"
> +#include "ioctl_wrappers.h"
> +#include "drmtest.h"
> +#include "intel_io.h"
> +#include "intel_chipset.h"
> +
> +#define WIDTH 512
> +#define HEIGHT 512
> +#define SIZE (WIDTH*HEIGHT*sizeof(uint32_t))
> +
> +#define PAGE_SIZE 4096
> +
> +static int tile_width;
> +static int tile_height;
> +static int tile_size;
> +
> +static uint32_t
> +create_bo(int fd)
> +{
> +	uint32_t handle;
> +	uint32_t *data;
> +	int i;
> +
> +	handle = gem_create(fd, SizE);
> +	gem_set_tiling(fd, handle, I915_TILING_X, WIDTH * sizeof(uint32_t));
> +
> +	/* Fill the BO with dwords starting at start_val */
> +	data = gem_mmap__wc(fd, handle, SIZE, PROT_READ | PROT_WRITE);
> +	for (i = 0; i < WIDTH*HEIGHT; i++)
> +		data[i] = i;
> +	munmap(data, SIZE);
> +
> +	return handle;
> +}
> +
> +static int
> +swizzle_bit(int bit, int offset)
> +{
> +	return (offset & (1 << bit)) >> (bit - 6);
> +}
> +
> +/* Translate from a swizzled offset in the tiled buffer to the corresponding
> + * value from the original linear buffer.
> + */
> +static uint32_t
> +calculate_expected(int offset)
> +{
> +	int tile_off = offset & (tile_size - 1);
> +	int tile_base = offset & -tile_size;
> +	int tile_index = tile_base / tile_size;
> +	int tiles_per_row = 4*WIDTH / tile_width;
> +
> +	/* base x,y values from the tile (page) index. */
> +	int base_y = tile_index / tiles_per_row * tile_height;
> +	int base_x = tile_index % tiles_per_row * (tile_width/4);
> +
> +	/* x, y offsets within the tile */
> +	int tile_y = tile_off / tile_width;
> +	int tile_x = (tile_off % tile_width) / 4;
> +
> +	igt_debug("%3d, %3d, %3d,%3d\n", base_x, base_y, tile_x, tile_y);
> +	return (base_y + tile_y) * WIDTH + base_x + tile_x;
> +}
> +
> +static void
> +get_tiling(int fd, uint32_t handle, uint32_t *tiling, uint32_t *swizzle)
> +{
> +	struct drm_i915_gem_get_tiling2 {
> +		uint32_t handle;
> +		uint32_t tiling_mode;
> +		uint32_t swizzle_mode;
> +		uint32_t phys_swizzle_mode;
> +	} arg;
> +#define DRM_IOCTL_I915_GEM_GET_TILING2	DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_GET_TILING, struct drm_i915_gem_get_tiling2)
> +
> +	memset(&arg, 0, sizeof(arg));
> +	arg.handle = handle;
> +
> +	do_or_die(drmIoctl(fd, DRM_IOCTL_I915_GEM_GET_TILING2, &arg));
> +	igt_requiee(arg.phys_swizzle_mode == arg.swizzle_mode);
> +
> +	*tiling = arg.tiling_mode;
> +	*swizzle = arg.swizzle_mode;
> +}
> +
> +igt_simple_main
> +{
> +	int fd;
> +	int i, iter = 100;
> +	uint32_t tiling, swizzle;
> +	uint32_t handle;
> +
> +	fd = drm_open_any();
> +
> +	igt_require_mmap_wc(fd);
> +	get_tiling(fd, handle, &tiling, &swizzle);
> +
> +	if (IS_GEN2(intel_get_drm_devid(fd))) {
> +		tile_height = 16;
> +		tile_width = 128;
> +		tile_size = 2048;
> +	} else {
> +		tile_height = 8;
> +		tile_width = 512;
> +		tile_size = PAGE_SIZE;
> +	}
> +
> +	handle = create_bo(fd);
> +
> +	/* Read a bunch of random subsets of the data and check that they come
> +	 * out right.
> +	 */
> +	for (i = 0; i < iter; i++) {
> +		int size = WIDTH * HEIGHT * 4;
> +		int offset = (random() % size) & ~3;
> +		int len = (random() % size) & ~3;
> +		int first_page, last_page;
> +		uint32_t *linear;
> +		int j;
> +
> +		if (len == 0)
> +			len = 4;
> +
> +		if (offset + len > size)
> +			len = size - offset;
> +
> +		if (i == 0) {
> +			offset = 0;
> +			len = size;
> +		}
> +
> +		first_page = offset & ~4095;
> +		last_page = (offset + len + 4095) & ~4095;
> +		offset -= first_page;
> +
> +		linear = gem_mmap__wc(fd, handle, first_page, last_page - first_page, PROT_READ);
> +		igt_assert(linear);
> +
> +		/* Translate from offsets in the read buffer to the swizzled
> +		 * address that it corresponds to.  This is the opposite of
> +		 * what Mesa does (calculate offset to be read given the linear
> +		 * offset it's looking for).
> +		 */
> +		for (j = offset; j < offset + len; j += 4) {
> +			uint32_t expected_val, found_val;
> +			int swizzled_offset;
> +			const char *swizzle_str;
> +
> +			switch (swizzle) {
> +			case I915_BIT_6_SWIZZLE_NONE:
> +				swizzled_offset = j;
> +				swizzle_str = "none";
> +				break;
> +			case I915_BIT_6_SWIZZLE_9:
> +				swizzled_offset = j ^
> +					swizzle_bit(9, j);
> +				swizzle_str = "bit9";
> +				break;
> +			case I915_BIT_6_SWIZZLE_9_10:
> +				swizzled_offset = j ^
> +					swizzle_bit(9, j) ^
> +					swizzle_bit(10, j);
> +				swizzle_str = "bit9^10";
> +				break;
> +			case I915_BIT_6_SWIZZLE_9_11:
> +				swizzled_offset = j ^
> +					swizzle_bit(9, j) ^
> +					swizzle_bit(11, j);
> +				swizzle_str = "bit9^11";
> +				break;
> +			case I915_BIT_6_SWIZZLE_9_10_11:
> +				swizzled_offset = j ^
> +					swizzle_bit(9, j) ^
> +					swizzle_bit(10, j) ^
> +					swizzle_bit(11, j);
> +				swizzle_str = "bit9^10^11";
> +				break;

I think an explicit list of all the bit17 swizzle modes we know about with
an igt_skip("bit17 swizzling") should be here. Otherwise the test will
fail. Otherwise lgtm.
-Daniel

> +			default:
> +				igt_assert_f(0, "Bad swizzle bits; %d\n",
> +					     swizzle);
> +			}
> +			expected_val = calculate_expected(swizzled_offset);
> +			found_val = linear[(j - offset) / 4];
> +			igt_assert_f(expected_val == found_val,
> +				     "Bad read [%d]: %d instead of %d at 0x%08x "
> +				     "for read from 0x%08x to 0x%08x, swizzle=%s\n",
> +				     i, found_val, expected_val, j,
> +				     offset, offset + len,
> +				     swizzle_str);
> +			munmap(linear, last_page - first_page);
> +		}
> +	}
> +
> +	close(fd);
> +}
> -- 
> 2.1.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch



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