[PATCH 4/9] fb: add hooks to handle KDB enter/exit
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From: Jason Wessel on 5 Aug 2010 10:50 From: Jesse Barnes <jbarnes(a)virtuousgeek.org> Add fb ops to handle enter/exit of the kernel debugger. If present, the fb core will register them with KGDB and they'll be called when the debugger is entered and exited. The new functions are responsible for switching to an appropriate debug framebuffer and restoring the interrupted state at exit time. Signed-off-by: Jesse Barnes <jbarnes(a)virtuousgeek.org> Signed-off-by: Jason Wessel <jason.wessel(a)windriver.com> --- drivers/video/console/fbcon.c | 26 ++++++++++++++++++++++++++ drivers/video/console/fbcon.h | 1 + include/linux/fb.h | 13 +++++++++++++ 3 files changed, 40 insertions(+), 0 deletions(-) diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c index b0a3fa0..3b3f574 100644 --- a/drivers/video/console/fbcon.c +++ b/drivers/video/console/fbcon.c @@ -2342,6 +2342,30 @@ static int fbcon_blank(struct vc_data *vc, int blank, int mode_switch) return 0; } +static int fbcon_debug_enter(struct vc_data *vc) +{ + struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]]; + struct fbcon_ops *ops = info->fbcon_par; + + ops->save_graphics = ops->graphics; + ops->graphics = 0; + if (info->fbops->fb_debug_enter) + info->fbops->fb_debug_enter(info); + fbcon_set_palette(vc, color_table); + return 0; +} + +static int fbcon_debug_leave(struct vc_data *vc) +{ + struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]]; + struct fbcon_ops *ops = info->fbcon_par; + + ops->graphics = ops->save_graphics; + if (info->fbops->fb_debug_leave) + info->fbops->fb_debug_leave(info); + return 0; +} + static int fbcon_get_font(struct vc_data *vc, struct console_font *font) { u8 *fontdata = vc->vc_font.data; @@ -3276,6 +3300,8 @@ static const struct consw fb_con = { .con_screen_pos = fbcon_screen_pos, .con_getxy = fbcon_getxy, .con_resize = fbcon_resize, + .con_debug_enter = fbcon_debug_enter, + .con_debug_leave = fbcon_debug_leave, }; static struct notifier_block fbcon_event_notifier = { diff --git a/drivers/video/console/fbcon.h b/drivers/video/console/fbcon.h index 89a3468..6bd2e0c 100644 --- a/drivers/video/console/fbcon.h +++ b/drivers/video/console/fbcon.h @@ -74,6 +74,7 @@ struct fbcon_ops { int cursor_reset; int blank_state; int graphics; + int save_graphics; /* for debug enter/leave */ int flags; int rotate; int cur_rotate; diff --git a/include/linux/fb.h b/include/linux/fb.h index e7445df..0c5659c 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -3,6 +3,9 @@ #include <linux/types.h> #include <linux/i2c.h> +#ifdef __KERNEL__ +#include <linux/kgdb.h> +#endif /* __KERNEL__ */ /* Definitions of frame buffers */ @@ -607,6 +610,12 @@ struct fb_deferred_io { * LOCKING NOTE: those functions must _ALL_ be called with the console * semaphore held, this is the only suitable locking mechanism we have * in 2.6. Some may be called at interrupt time at this point though. + * + * The exception to this is the debug related hooks. Putting the fb + * into a debug state (e.g. flipping to the kernel console) and restoring + * it must be done in a lock-free manner, so low level drivers should + * keep track of the initial console (if applicable) and may need to + * perform direct, unlocked hardware writes in these hooks. */ struct fb_ops { @@ -676,6 +685,10 @@ struct fb_ops { /* teardown any resources to do with this framebuffer */ void (*fb_destroy)(struct fb_info *info); + + /* called at KDB enter and leave time to prepare the console */ + int (*fb_debug_enter)(struct fb_info *info); + int (*fb_debug_leave)(struct fb_info *info); }; #ifdef CONFIG_FB_TILEBLITTING -- 1.6.4.rc1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |