Re: [PATCH v3 14/14] drm/panic: Compile KUnit tests as module

v3:
- clean up after each test case (Sashiko)
v2:
- fix parameter order in decl of drm_panic_helper_draw_screen_qr()
   (Sashiko)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
  drivers/gpu/drm/Kconfig.debug                 |  1 +
  drivers/gpu/drm/drm_panic_helper.c            | 26 ++++++++++---------
  drivers/gpu/drm/tests/Makefile                |  1 +
  drivers/gpu/drm/tests/drm_panic_helper_test.c | 21 ++++++++++++---
  include/drm/drm_panic_helper.h                |  8 ++++++
  5 files changed, 41 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig.debug b/drivers/gpu/drm/Kconfig.debug
index 1f4c98cbf090..b909cd0a619f 100644
--- a/drivers/gpu/drm/Kconfig.debug
+++ b/drivers/gpu/drm/Kconfig.debug

@@ -69,6 +69,7 @@ config DRM_KUNIT_TEST
  	select DRM_EXPORT_FOR_TESTS if m
  	select DRM_GEM_SHMEM_HELPER
  	select DRM_KUNIT_TEST_HELPERS
+	select DRM_PANIC_HELPER
  	select DRM_SYSFB_HELPER
  	select PRIME_NUMBERS
  	default KUNIT_ALL_TESTS

diff --git a/drivers/gpu/drm/drm_panic_helper.c b/drivers/gpu/drm/drm_panic_helper.c
index f64a3ca38467..683af48de38c 100644
--- a/drivers/gpu/drm/drm_panic_helper.c
+++ b/drivers/gpu/drm/drm_panic_helper.c

@@ -8,6 +8,8 @@
  #include <linux/utsname.h>
  #include <linux/zlib.h>
  
+#include <kunit/visibility.h>
+
  #include <drm/drm_fourcc.h>
  #include <drm/drm_framebuffer.h>
  #include <drm/drm_modeset_helper_vtables.h>

@@ -433,8 +435,8 @@ static void drm_panic_helper_logo_draw(struct drm_scanout_buffer *sb, struct drm
  				   fg_color);
  }
  
-static int drm_panic_helper_draw_screen_user(struct drm_scanout_buffer *sb,
-					     u32 fg_color, u32 bg_color)
+VISIBLE_IF_KUNIT int drm_panic_helper_draw_screen_user(struct drm_scanout_buffer *sb,
+						       u32 fg_color, u32 bg_color)
  {
  	const struct font_desc *font = get_default_font(sb->width, sb->height, NULL, NULL);
  	struct drm_rect r_screen, r_logo, r_msg;

@@ -466,6 +468,7 @@ static int drm_panic_helper_draw_screen_user(struct drm_scanout_buffer *sb,
  
  	return 0;
  }
+EXPORT_SYMBOL_IF_KUNIT(drm_panic_helper_draw_screen_user);
  
  /*
   * Draw one line of kmsg, and handle wrapping if it won't fit in the screen width.

@@ -504,8 +507,8 @@ static int draw_line_with_wrap(struct drm_scanout_buffer *sb, const struct font_
   * Draw the kmsg buffer to the screen, starting from the youngest message at the bottom,
   * and going up until reaching the top of the screen.
   */
-static int drm_panic_helper_draw_screen_kmsg(struct drm_scanout_buffer *sb,
-					     u32 fg_color, u32 bg_color)
+VISIBLE_IF_KUNIT int drm_panic_helper_draw_screen_kmsg(struct drm_scanout_buffer *sb,
+						       u32 fg_color, u32 bg_color)
  {
  	const struct font_desc *font = get_default_font(sb->width, sb->height, NULL, NULL);
  	struct drm_rect r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height);

@@ -549,6 +552,7 @@ static int drm_panic_helper_draw_screen_kmsg(struct drm_scanout_buffer *sb,
  
  	return 0;
  }
+EXPORT_SYMBOL_IF_KUNIT(drm_panic_helper_draw_screen_kmsg);
  
  #if defined(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
  /*

@@ -691,9 +695,9 @@ static int drm_panic_helper_get_qr_code(u8 **qr_image, unsigned int qr_version)
  /*
   * Draw the panic message at the center of the screen, with a QR Code
   */
-static int drm_panic_helper_draw_screen_qr_code(struct drm_scanout_buffer *sb,
-						u32 fg_color, u32 bg_color,
-						unsigned int qr_version)
+VISIBLE_IF_KUNIT int drm_panic_helper_draw_screen_qr_code(struct drm_scanout_buffer *sb,
+							  u32 fg_color, u32 bg_color,
+							  unsigned int qr_version)
  {
  	const struct font_desc *font = get_default_font(sb->width, sb->height, NULL, NULL);
  	struct drm_rect r_screen, r_logo, r_msg, r_qr, r_qr_canvas;

@@ -763,6 +767,7 @@ static int drm_panic_helper_draw_screen_qr_code(struct drm_scanout_buffer *sb,
  	drm_panic_helper_blit(sb, &r_qr, qr_image, qr_pitch, scale, fg_color);
  	return 0;
  }
+EXPORT_SYMBOL_IF_KUNIT(drm_panic_helper_draw_screen_qr_code);
  #else
  static void __init drm_panic_helper_qr_init(void) { };
  static void __exit drm_panic_helper_qr_exit(void) { };

@@ -815,7 +820,7 @@ static int draw_panic_helper_dispatch(struct drm_scanout_buffer *sb,
  	return ret;
  }
  
-static void drm_panic_helper_set_description(const char *description)
+VISIBLE_IF_KUNIT void drm_panic_helper_set_description(const char *description)
  {
  	u32 len;
  

@@ -830,6 +835,7 @@ static void drm_panic_helper_set_description(const char *description)
  		desc_line->len = len;
  	}
  }
+EXPORT_SYMBOL_IF_KUNIT(drm_panic_helper_set_description);
  
  static void drm_panic_helper_clear_description(void)
  {

@@ -910,7 +916,3 @@ void __exit drm_panic_helper_exit(void)
  {
  	drm_panic_helper_qr_exit();
  }
-
-#ifdef CONFIG_DRM_KUNIT_TEST
-#include "tests/drm_panic_helper_test.c"
-#endif

diff --git a/drivers/gpu/drm/tests/Makefile b/drivers/gpu/drm/tests/Makefile
index e7193b49cf91..42207df1d1c8 100644
--- a/drivers/gpu/drm/tests/Makefile
+++ b/drivers/gpu/drm/tests/Makefile

@@ -20,6 +20,7 @@ obj-$(CONFIG_DRM_KUNIT_TEST) += \
  	drm_managed_test.o \
  	drm_mm_test.o \
  	drm_modes_test.o \
+	drm_panic_helper_test.o \
  	drm_plane_helper_test.o \
  	drm_probe_helper_test.o \
  	drm_rect_test.o \

diff --git a/drivers/gpu/drm/tests/drm_panic_helper_test.c b/drivers/gpu/drm/tests/drm_panic_helper_test.c
index e6befe0f1c83..6184a6fc7eb8 100644
--- a/drivers/gpu/drm/tests/drm_panic_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_panic_helper_test.c

@@ -6,13 +6,17 @@
   * KUNIT tests for DRM panic helpers
   */
  
-#include <drm/drm_fourcc.h>
-#include <drm/drm_panic.h>
+#include <linux/highmem.h>
+#include <linux/units.h>
+#include <linux/vmalloc.h>
  
  #include <kunit/test.h>
  
-#include <linux/units.h>
-#include <linux/vmalloc.h>
+#include <drm/drm_fourcc.h>
+#include <drm/drm_panic.h>
+#include <drm/drm_panic_helper.h>
+
+MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
  
  static void drm_panic_check_color_byte(struct kunit *test, u8 b)
  {

@@ -86,6 +90,11 @@ static int drm_test_panic_init(struct kunit *test)
  	return 0;
  }
  
+static void drm_test_panic_exit(struct kunit *test)
+{
+	drm_panic_helper_set_description(NULL);
+}
+
  /*
   * Test drawing the panic screen, using a memory mapped framebuffer
   * Set the whole buffer to 0xa5, and then check that all pixels have been

@@ -229,7 +238,11 @@ static struct kunit_case drm_panic_screen_user_test[] = {
  static struct kunit_suite drm_panic_helper_suite = {
  	.name = "drm_panic_helper",
  	.init = drm_test_panic_init,
+	.exit = drm_test_panic_exit,
  	.test_cases = drm_panic_screen_user_test,
  };
  
  kunit_test_suite(drm_panic_helper_suite);
+
+MODULE_DESCRIPTION("KUnit test suite for DRM panic handling");
+MODULE_LICENSE("GPL");

diff --git a/include/drm/drm_panic_helper.h b/include/drm/drm_panic_helper.h
index 6cc9a0eba077..6b19607e0784 100644
--- a/include/drm/drm_panic_helper.h
+++ b/include/drm/drm_panic_helper.h

@@ -8,6 +8,7 @@
  enum drm_panic_type;
  
  struct drm_plane;
+struct drm_scanout_buffer;
  
  /* drm_panic_helper.c */
  int drm_plane_helper_display_panic_screen(struct drm_plane *plane,

@@ -15,6 +16,13 @@ int drm_plane_helper_display_panic_screen(struct drm_plane *plane,
  					  enum drm_panic_type panic_type,
  					  u32 fg_color, u32 bg_color,
  					  unsigned int qr_version);
+#if IS_ENABLED(CONFIG_KUNIT)
+int drm_panic_helper_draw_screen_user(struct drm_scanout_buffer *sb, u32 fg_color, u32 bg_color);
+int drm_panic_helper_draw_screen_kmsg(struct drm_scanout_buffer *sb, u32 fg_color, u32 bg_color);
+int drm_panic_helper_draw_screen_qr_code(struct drm_scanout_buffer *sb,
+					 u32 fg_color, u32 bg_color, unsigned int qr_version);
+void drm_panic_helper_set_description(const char *description);
+#endif
  
  /* drm_panic_helper_qr.rs */
  size_t drm_panic_helper_qr_max_data_size(u8 version, size_t url_len);