This adds support for outputting kernel messages on panic(). A kernel message dumper is used to dump the log. The dumper iterates over each DRM device and it's crtc's to find suitable framebuffers.
All the other dumpers are run before this one except mtdoops. Only atomic drivers are supported.
Signed-off-by: Noralf Trønnes noralf@tronnes.org --- drivers/gpu/drm/Kconfig | 3 + drivers/gpu/drm/drm_drv.c | 3 + drivers/gpu/drm/drm_framebuffer.c | 117 ++++++++++ drivers/gpu/drm/drm_internal.h | 4 + drivers/gpu/drm/drm_panic.c | 363 ++++++++++++++++++++++++++++++ include/drm/drm_framebuffer.h | 41 ++++ 6 files changed, 531 insertions(+) create mode 100644 drivers/gpu/drm/drm_panic.c
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index bd943a71756c..74c37542f857 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -14,6 +14,9 @@ menuconfig DRM select I2C_ALGOBIT select DMA_SHARED_BUFFER select SYNC_FILE + select FONT_SUPPORT + select FONT_8x8 + select FONT_8x16 help Kernel-level support for the Direct Rendering Infrastructure (DRI) introduced in XFree86 4.0. If you say Y here, you need to select diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 50d849d1bc6e..b0b870b5dd55 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -1147,6 +1147,7 @@ static const struct file_operations drm_stub_fops = {
static void drm_core_exit(void) { + drm_panic_exit(drm_debugfs_root); unregister_chrdev(DRM_MAJOR, "drm"); debugfs_remove(drm_debugfs_root); drm_sysfs_destroy(); @@ -1178,6 +1179,8 @@ static int __init drm_core_init(void) if (ret < 0) goto error;
+ drm_panic_init(drm_debugfs_root); + drm_core_init_complete = true;
DRM_DEBUG("Initialized\n"); diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c index d8d75e25f6fb..da2285c5ae90 100644 --- a/drivers/gpu/drm/drm_framebuffer.c +++ b/drivers/gpu/drm/drm_framebuffer.c @@ -1087,3 +1087,120 @@ int drm_framebuffer_debugfs_init(struct drm_minor *minor) minor->debugfs_root, minor); } #endif + +/** + * drm_framebuffer_panic_draw_xy - draw pixel on fb during panic() + * @fb: DRM framebuffer + * @vmap: Linear virtual mapping + * @x: X coordinate + * @y: Y coordinate + * @foreground: Foreground pixel + * + * This function can be used to draw a pixel during panic message rendering. + * It requires @vmap to be a linear mapping. This is the default implementation + * used if &drm_framebuffer_funcs->panic_draw_xy is not set. + */ +void drm_framebuffer_panic_draw_xy(struct drm_framebuffer *fb, void *vmap, + int x, int y, bool foreground) +{ + void *pix = vmap + fb->offsets[0] + (y * fb->pitches[0]); + u8 *pix8 = pix; + u16 *pix16 = pix; + u32 *pix32 = pix; + + switch (fb->format->format & ~DRM_FORMAT_BIG_ENDIAN) { + case DRM_FORMAT_C8: + + case DRM_FORMAT_RGB332: + case DRM_FORMAT_BGR233: + + case DRM_FORMAT_NV12: + case DRM_FORMAT_NV21: + case DRM_FORMAT_NV16: + case DRM_FORMAT_NV61: + case DRM_FORMAT_NV24: + case DRM_FORMAT_NV42: + + case DRM_FORMAT_YUV410: + case DRM_FORMAT_YVU410: + case DRM_FORMAT_YUV411: + case DRM_FORMAT_YVU411: + case DRM_FORMAT_YUV420: + case DRM_FORMAT_YVU420: + case DRM_FORMAT_YUV422: + case DRM_FORMAT_YVU422: + case DRM_FORMAT_YUV444: + case DRM_FORMAT_YVU444: + pix8[x] = foreground ? 0xff : 0x00; + break; + + case DRM_FORMAT_XRGB4444: + case DRM_FORMAT_ARGB4444: + case DRM_FORMAT_XBGR4444: + case DRM_FORMAT_ABGR4444: + pix16[x] = foreground ? 0xffff : 0xf000; + break; + + case DRM_FORMAT_RGBX4444: + case DRM_FORMAT_RGBA4444: + case DRM_FORMAT_BGRX4444: + case DRM_FORMAT_BGRA4444: + pix16[x] = foreground ? 0xffff : 0x000f; + break; + + case DRM_FORMAT_XRGB1555: + case DRM_FORMAT_ARGB1555: + case DRM_FORMAT_XBGR1555: + case DRM_FORMAT_ABGR1555: + pix16[x] = foreground ? 0xffff : 0x8000; + break; + + case DRM_FORMAT_RGBX5551: + case DRM_FORMAT_RGBA5551: + case DRM_FORMAT_BGRX5551: + case DRM_FORMAT_BGRA5551: + pix16[x] = foreground ? 0xffff : 0x0001; + break; + + case DRM_FORMAT_RGB565: + case DRM_FORMAT_BGR565: + pix16[x] = foreground ? 0xffff : 0x0000; + break; + + case DRM_FORMAT_RGB888: + case DRM_FORMAT_BGR888: + pix8[x * 3] = foreground ? 0xff : 0x00; + pix8[(x * 3) + 1] = pix8[x]; + pix8[(x * 3) + 2] = pix8[x]; + break; + + case DRM_FORMAT_XRGB8888: + case DRM_FORMAT_ARGB8888: + case DRM_FORMAT_XBGR8888: + case DRM_FORMAT_ABGR8888: + pix32[x] = foreground ? 0xffffffff : 0xff000000; + break; + + case DRM_FORMAT_RGBX8888: + case DRM_FORMAT_RGBA8888: + case DRM_FORMAT_BGRX8888: + case DRM_FORMAT_BGRA8888: + pix32[x] = foreground ? 0xffffffff : 0x000000ff; + break; + + case DRM_FORMAT_XRGB2101010: + case DRM_FORMAT_ARGB2101010: + case DRM_FORMAT_XBGR2101010: + case DRM_FORMAT_ABGR2101010: + pix32[x] = foreground ? 0xffffffff : 0xc0000000; + break; + + case DRM_FORMAT_RGBX1010102: + case DRM_FORMAT_RGBA1010102: + case DRM_FORMAT_BGRX1010102: + case DRM_FORMAT_BGRA1010102: + pix32[x] = foreground ? 0xffffffff : 0x00000003; + break; + } +} +EXPORT_SYMBOL(drm_framebuffer_panic_draw_xy); diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h index 251d67e04c2d..694a5803ac3c 100644 --- a/drivers/gpu/drm/drm_internal.h +++ b/drivers/gpu/drm/drm_internal.h @@ -191,3 +191,7 @@ int drm_syncobj_signal_ioctl(struct drm_device *dev, void *data, void drm_framebuffer_print_info(struct drm_printer *p, unsigned int indent, const struct drm_framebuffer *fb); int drm_framebuffer_debugfs_init(struct drm_minor *minor); + +/* drm_panic.c */ +void drm_panic_init(struct dentry *debugfs_root); +void drm_panic_exit(struct dentry *debugfs_root); diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c new file mode 100644 index 000000000000..4bca7f0bc369 --- /dev/null +++ b/drivers/gpu/drm/drm_panic.c @@ -0,0 +1,363 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright 2018 Noralf Trønnes + +#include <linux/debugfs.h> +#include <linux/font.h> +#include <linux/kernel.h> +#include <linux/kmsg_dump.h> +#include <linux/seq_file.h> +#include <linux/slab.h> +#include <linux/uaccess.h> + +#include <drm/drm_crtc.h> +#include <drm/drm_device.h> +#include <drm/drm_drv.h> +#include <drm/drm_file.h> +#include <drm/drm_framebuffer.h> +#include <drm/drm_fb_helper.h> +#include <drm/drm_plane.h> +#include <drm/drm_print.h> +#include <drm/drmP.h> + +#include "drm_internal.h" + +/* + * The log lines in an ARM stack dump are 92 characters long + * and 120 is a nice multiple for HD and 4K. + */ +#define DRM_PANIC_COLUMN_WIDTH 120 + +struct drm_panic_ctx { + struct drm_framebuffer *fb; + unsigned int width; + unsigned int height; + void *vmap; + + const struct font_desc *font; + unsigned int col_width; + unsigned int bottom_y; + size_t max_line_length; + + unsigned int x; + unsigned int y; +}; + +static const struct font_desc *drm_panic_font8x8, *drm_panic_font8x16; + +static void drm_panic_draw_xy(struct drm_framebuffer *fb, void *vmap, + int x, int y, bool fg) +{ + if (fb->funcs->panic_draw_xy) + fb->funcs->panic_draw_xy(fb, vmap, x, y, fg); + else + drm_framebuffer_panic_draw_xy(fb, vmap, x, y, fg); +} + +static void drm_panic_render_char(struct drm_panic_ctx *ctx, + unsigned int offset, char c) +{ + unsigned int h, w, x, y; + u8 fontline; + + for (h = 0; h < ctx->font->height; h++) { + fontline = *(u8 *)(ctx->font->data + c * ctx->font->height + h); + + for (w = 0; w < ctx->font->width; w++) { + x = ctx->x + (offset * ctx->font->width) + w; + y = ctx->y + h; + drm_panic_draw_xy(ctx->fb, ctx->vmap, x, y, + fontline & BIT(7 - w)); + } + } +} + +static void drm_panic_render_line(struct drm_panic_ctx *ctx, + const char *line, size_t len) +{ + unsigned int i; + + for (i = 0; i < len; i++) + drm_panic_render_char(ctx, i, line[i]); + + /* Clear out the rest of the line */ + for (i = len; i < ctx->max_line_length; i++) + drm_panic_render_char(ctx, i, ' '); +} + +static bool drm_panic_newline(struct drm_panic_ctx *ctx) +{ + if (ctx->x == 0 && ctx->y == 0) + return false; + if (ctx->y == 0) { + ctx->x -= ctx->col_width; + ctx->y = ctx->bottom_y; + } else { + ctx->y -= ctx->font->height; + } + + return true; +} + +/* Render from bottom right most column */ +static bool drm_panic_render_lines(struct drm_panic_ctx *ctx, + const char *str, size_t len) +{ + size_t l, line_length; + const char *pos; + int i; + + while (len) { + pos = str + len - 1; + + if (*pos == '\n') { + len--; + if (!drm_panic_newline(ctx)) + return false; + continue; + } + + while (pos > str && *(pos - 1) != '\n') + pos--; + + line_length = len - (pos - str); + + if (!line_length || len < line_length) { + pr_err("%s: Bug! line_length=%zu len=%zu\n", + __func__, line_length, len); + return false; + } + + len -= line_length; + + for (i = DIV_ROUND_UP(line_length, ctx->max_line_length) - 1; i >= 0; i--) { + l = min(ctx->max_line_length, line_length - i * ctx->max_line_length); + drm_panic_render_line(ctx, pos + (i * ctx->max_line_length), l); + if (i && !drm_panic_newline(ctx)) + return false; + } + } + + return true; +} + +static void drm_panic_kmsg_render_screen(struct drm_plane *plane, + struct kmsg_dumper *dumper) +{ + struct drm_framebuffer *fb = plane->state->fb; + bool first_iteration = true; + struct drm_panic_ctx ctx; + static char text[1024]; + size_t len; + + ctx.vmap = fb->funcs->panic_vmap(fb); + + /* Print some info when testing */ + if (dumper->max_reason == KMSG_DUMP_OOPS) { + struct drm_format_name_buf format_name; + + pr_info("%s: [FB:%d] %ux%u format=%s vmap=%p\n", + __func__, fb->base.id, fb->width, fb->height, + drm_get_format_name(fb->format->format, &format_name), + ctx.vmap); + } + + if (!ctx.vmap) + return; + + ctx.fb = fb; + ctx.width = drm_rect_width(&plane->state->src) >> 16; + ctx.height = drm_rect_height(&plane->state->src) >> 16; + + /* + * TODO: + * Find which part of the fb that is visible. + * Width and height are zero on vc4 + */ + if (!ctx.width || !ctx.height) { + ctx.width = fb->width; + ctx.height = fb->height; + } + + /* Try to fit 50 lines */ + if (ctx.height < 50 * 16 && drm_panic_font8x8) + ctx.font = drm_panic_font8x8; + else + ctx.font = drm_panic_font8x16; + + ctx.col_width = DRM_PANIC_COLUMN_WIDTH * ctx.font->width; + ctx.bottom_y = ((ctx.height / ctx.font->height) - 1) * ctx.font->height; + + if (ctx.width < 2 * ctx.col_width) + ctx.max_line_length = ctx.width / ctx.font->width; + else + ctx.max_line_length = DRM_PANIC_COLUMN_WIDTH - 2; /* border=2 */ + + ctx.x = 0; + ctx.y = ctx.bottom_y; + if (ctx.width > ctx.col_width) + ctx.x = ((ctx.width / ctx.col_width) - 1) * ctx.col_width; + + pr_debug("%s: font=%s %ux%u max_line_length=%zu (%u,%u)\n", + __func__, ctx.font->name, ctx.width, ctx.height, + ctx.max_line_length, ctx.x, ctx.y); + + kmsg_dump_rewind(dumper); + + /* The latest messages are fetched first */ + while (kmsg_dump_get_buffer(dumper, false, text, sizeof(text), &len)) { + /* Strip off the very last newline so we start at the bottom */ + if (first_iteration) { + len--; + first_iteration = false; + } + + if (!drm_panic_render_lines(&ctx, text, len)) + break; + } + + if (fb->funcs->panic_vunmap) + fb->funcs->panic_vunmap(fb, vmap); +} + +static void drm_panic_try_dev(struct drm_device *dev, struct kmsg_dumper *dumper) +{ + struct drm_framebuffer *fb; + struct drm_plane *plane; + struct drm_crtc *crtc; + + if (!drm_core_check_feature(dev, DRIVER_ATOMIC)) + return; + + if (dumper->max_reason == KMSG_DUMP_OOPS) + pr_info("%s: %s on minor %d\n", __func__, dev->driver->name, + dev->primary->index); + + drm_for_each_crtc(crtc, dev) { + if (!ww_mutex_trylock(&crtc->mutex.mutex)) + continue; + + if (!crtc->enabled || !crtc->primary) + goto crtc_unlock; + + if (!crtc->state || !crtc->state->active) + goto crtc_unlock; + + plane = crtc->primary; + if (!ww_mutex_trylock(&plane->mutex.mutex)) + goto crtc_unlock; + + /* + * TODO: Should we check plane_state->visible? + * It is not set on vc4 + if (!plane->state || !plane->state->visible) + */ + if (!plane->state) + goto plane_unlock; + + fb = plane->state->fb; + if (!fb || !fb->funcs->panic_vmap) + goto plane_unlock; + + /* + * fbcon puts out panic messages so stay away to avoid jumbled + * output. If vc->vc_mode != KD_TEXT fbcon won't put out + * messages (see vt_console_print). + */ + if (dev->fb_helper && dev->fb_helper->fb == fb) + goto plane_unlock; + + drm_panic_kmsg_render_screen(plane, dumper); +plane_unlock: + ww_mutex_unlock(&plane->mutex.mutex); +crtc_unlock: + ww_mutex_unlock(&crtc->mutex.mutex); + } +} + +static int drm_panic_dev_iter(struct device *dev, void *data) +{ + struct drm_minor *minor = dev_get_drvdata(dev); + + if (minor && minor->type == DRM_MINOR_PRIMARY) + drm_panic_try_dev(minor->dev, data); + + return 0; +} + +static void drm_panic_kmsg_dump(struct kmsg_dumper *dumper, + enum kmsg_dump_reason reason) +{ + class_for_each_device(drm_class, NULL, dumper, drm_panic_dev_iter); +} + +static struct kmsg_dumper drm_panic_kmsg_dumper = { + .dump = drm_panic_kmsg_dump, + .max_reason = KMSG_DUMP_PANIC, +}; + +static ssize_t drm_panic_file_panic_write(struct file *file, + const char __user *user_buf, + size_t count, loff_t *ppos) +{ + unsigned long long val; + char buf[24]; + size_t size; + ssize_t ret; + + size = min(sizeof(buf) - 1, count); + if (copy_from_user(buf, user_buf, size)) + return -EFAULT; + + buf[size] = '\0'; + ret = kstrtoull(buf, 0, &val); + if (ret) + return ret; + + drm_panic_kmsg_dumper.max_reason = KMSG_DUMP_OOPS; + wmb(); + + /* Do a real test with: echo c > /proc/sysrq-trigger */ + + if (val == 0) { + pr_info("Test panic screen using kmsg_dump(OOPS)\n"); + kmsg_dump(KMSG_DUMP_OOPS); + } else if (val == 1) { + char *null_pointer = NULL; + + pr_info("Test panic screen using NULL pointer dereference\n"); + *null_pointer = 1; + } else { + return -EINVAL; + } + + return count; +} + +static const struct file_operations drm_panic_panic_ops = { + .write = drm_panic_file_panic_write, + .open = simple_open, + .llseek = default_llseek, +}; + +static struct dentry *drm_panic_d_panic; + +void __init drm_panic_init(struct dentry *debugfs_root) +{ + drm_panic_font8x8 = find_font("VGA8x8"); + drm_panic_font8x16 = find_font("VGA8x16"); + if (!drm_panic_font8x16) { + DRM_WARN("Couldn't find font, panic screen disabled\n"); + return; + } + + drm_panic_d_panic = debugfs_create_file("panic-test", 0200, + debugfs_root, NULL, + &drm_panic_panic_ops); + kmsg_dump_register(&drm_panic_kmsg_dumper); +} + +void drm_panic_exit(struct dentry *debugfs_root) +{ + kmsg_dump_unregister(&drm_panic_kmsg_dumper); + debugfs_remove(drm_panic_d_panic); +} diff --git a/include/drm/drm_framebuffer.h b/include/drm/drm_framebuffer.h index f0b34c977ec5..f3274798ecfe 100644 --- a/include/drm/drm_framebuffer.h +++ b/include/drm/drm_framebuffer.h @@ -94,6 +94,44 @@ struct drm_framebuffer_funcs { struct drm_file *file_priv, unsigned flags, unsigned color, struct drm_clip_rect *clips, unsigned num_clips); + + /** + * @panic_vmap: + * + * Optional callback for panic handling. + * + * For vmapping the selected framebuffer in a panic context. Must + * be super careful about locking (only trylocking allowed). + * + * RETURNS: + * + * NULL if it didn't work out, otherwise an opaque cookie which is + * passed to @panic_draw_xy. It can be anything: vmap area, structure + * with more details, just a few flags, ... + */ + void *(*panic_vmap)(struct drm_framebuffer *fb); + + /** + * @panic_vunmap: + * + * Optional callback for cleaning up after panic testing. + * + * Crtc and plane locks are released after this callback has run. + * vmap is the cookie returned by @panic_vmap. + */ + void (*panic_vunmap)(struct drm_framebuffer *fb, void *vmap); + + /** + * @panic_draw_xy: + * + * Optional callback for drawing pixels during panic. + * + * For drawing pixels onto a framebuffer prepared with @panic_vmap. + * vmap is the cookie returned by @panic_vmap. + * If it's not set, drm_framebuffer_panic_draw_xy() is used. + */ + void (*panic_draw_xy)(struct drm_framebuffer *fb, void *vmap, + int x, int y, bool foreground); };
/** @@ -293,4 +331,7 @@ int drm_framebuffer_plane_width(int width, int drm_framebuffer_plane_height(int height, const struct drm_framebuffer *fb, int plane);
+void drm_framebuffer_panic_draw_xy(struct drm_framebuffer *fb, void *vmap, + int x, int y, bool foreground); + #endif