[PATCH 5.4 024/168] drm/modes: Make sure to parse valid rotation value from cmdline

Greg Kroah-Hartman
2020-03-10T12:51:07Z

From: Stephan Gerhold <stephan@gerhold.net>

[ Upstream commit e6980a727154b793adb218fbc7b4d6af52a7e364 ]

A rotation value should have exactly one rotation angle.
At the moment there is no validation for this when parsing video=
parameters from the command line. This causes problems later on
when we try to combine the command line rotation with the panel
orientation.

To make sure that we generate a valid rotation value:
- Set DRM_MODE_ROTATE_0 by default (if no rotate= option is set)
- Validate that there is exactly one rotation angle set
(i.e. specifying the rotate= option multiple times is invalid)

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20200117153429.54700-2-stephan@gerhold.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/drm_modes.c | 7 +++++++
drivers/gpu/drm/selftests/drm_cmdline_selftests.h | 1 +
.../gpu/drm/selftests/test-drm_cmdline_parser.c | 15 +++++++++++++--
3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 88232698d7a00..3fd35e6b9d535 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -1672,6 +1672,13 @@ static int drm_mode_parse_cmdline_options(char *str, size_t len,
}
}

+ if (!(rotation & DRM_MODE_ROTATE_MASK))
+ rotation |= DRM_MODE_ROTATE_0;
+
+ /* Make sure there is exactly one rotation defined */
+ if (!is_power_of_2(rotation & DRM_MODE_ROTATE_MASK))
+ return -EINVAL;
+
mode->rotation_reflection = rotation;

return 0;
diff --git a/drivers/gpu/drm/selftests/drm_cmdline_selftests.h b/drivers/gpu/drm/selftests/drm_cmdline_selftests.h
index 6d61a0eb5d64f..84e6bc050bf2c 100644
--- a/drivers/gpu/drm/selftests/drm_cmdline_selftests.h
+++ b/drivers/gpu/drm/selftests/drm_cmdline_selftests.h
@@ -53,6 +53,7 @@ cmdline_test(drm_cmdline_test_rotate_0)
cmdline_test(drm_cmdline_test_rotate_90)
cmdline_test(drm_cmdline_test_rotate_180)
cmdline_test(drm_cmdline_test_rotate_270)
+cmdline_test(drm_cmdline_test_rotate_multiple)
cmdline_test(drm_cmdline_test_rotate_invalid_val)
cmdline_test(drm_cmdline_test_rotate_truncated)
cmdline_test(drm_cmdline_test_hmirror)
diff --git a/drivers/gpu/drm/selftests/test-drm_cmdline_parser.c b/drivers/gpu/drm/selftests/test-drm_cmdline_parser.c
index 013de9d27c35d..035f86c5d6482 100644
--- a/drivers/gpu/drm/selftests/test-drm_cmdline_parser.c
+++ b/drivers/gpu/drm/selftests/test-drm_cmdline_parser.c
@@ -856,6 +856,17 @@ static int drm_cmdline_test_rotate_270(void *ignored)
return 0;
}

+static int drm_cmdline_test_rotate_multiple(void *ignored)
+{
+ struct drm_cmdline_mode mode = { };
+
+ FAIL_ON(drm_mode_parse_command_line_for_connector("720x480,rotate=0,rotate=90",
+ &no_connector,
+ &mode));
+
+ return 0;
+}
+
static int drm_cmdline_test_rotate_invalid_val(void *ignored)
{
struct drm_cmdline_mode mode = { };
@@ -888,7 +899,7 @@ static int drm_cmdline_test_hmirror(void *ignored)
FAIL_ON(!mode.specified);
FAIL_ON(mode.xres != 720);
FAIL_ON(mode.yres != 480);
- FAIL_ON(mode.rotation_reflection != DRM_MODE_REFLECT_X);
+ FAIL_ON(mode.rotation_reflection != (DRM_MODE_ROTATE_0 | DRM_MODE_REFLECT_X));

FAIL_ON(mode.refresh_specified);

@@ -913,7 +924,7 @@ static int drm_cmdline_test_vmirror(void *ignored)
FAIL_ON(!mode.specified);
FAIL_ON(mode.xres != 720);
FAIL_ON(mode.yres != 480);
- FAIL_ON(mode.rotation_reflection != DRM_MODE_REFLECT_Y);
+ FAIL_ON(mode.rotation_reflection != (DRM_MODE_ROTATE_0 | DRM_MODE_REFLECT_Y));

FAIL_ON(mode.refresh_specified);

--
2.20.1