arch/x86_64-pc/kernel/kernel_debug.c

   1 #include <bootconsole.h>
   2
   3 #include "kernel_base.h"
   4 #include "kernel_debug.h"
   5 #include "kernel_intern.h"
   6
   7 #define __save_flags(x)         __asm__ __volatile__("pushfq ; popq %0":"=g" (x): /* no input */)
   8 #define __restore_flags(x)      __asm__ __volatile__("pushq %0 ; popfq": /* no output */ :"g" (x):"memory", "cc")
   9 #define __cli()                 __asm__ __volatile__("cli": : :"memory")
  10 #define __sti()                 __asm__ __volatile__("sti": : :"memory")
  11
  12 int krnPutC(int c, struct KernelBase *KernelBase)
  13 {
  14     unsigned long flags;
  15
  16     __save_flags(flags);
  17
  18     /*
  19      * stegerg: Don't use Disable/Enable, because we want  interrupt enabled flag
  20      * to stay the same as it was before the Disable() call
  21      */
  22     __cli();
  23
  24     /*
  25      * If we got 0x03, this means graphics driver wants to take over the screen.
  26      * If VESA hack is activated, it will use only upper half of the screen
  27      * because y resolution was adjusted.
  28      * In our turn, we need to switch over to lower half.
  29      * VESA hack is supported only on graphical console of course. And do not
  30      * expect it to work with native mode video driver. :)
  31      */
  32     if ((c == 0x03) && (scr_Type == SCR_GFX) && __KernBootPrivate->debug_framebuffer)
  33     {
  34         /* Reinitialize boot console with decreased height */
  35         scr_FrameBuffer = __KernBootPrivate->debug_framebuffer;
  36         fb_Resize(__KernBootPrivate->debug_y_resolution);
  37     }
  38     else
  39         con_Putc(c);
  40
  41     /*
  42      * Interrupt flag is stored in flags - if it was enabled before,
  43      * it will be renabled when the flags are restored
  44      */
  45     __restore_flags(flags);
  46
  47     return 1;
  48 }