mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-07-04 18:28:30 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Show "screen of death" on VGA console upon program crash (#650)

Browse source 
* [metal] Refactoring: separate out sys_writev_vga() and _vga_init() modules

* [metal] Read VGA info from BDA before long mode entry, not after

If using a pre-existing VGA text console, the VGA initialization
code now retrieves the cursor position & character height from
the BIOS data area while still in real mode — rather than
reading from the BIOS data area only after entering long mode.

(This should help make the code more correct, if Cosmopolitan
were to support UEFI graphics output in the future.  If the
program were booted via UEFI, then the long mode IsMetal()
code would still be activated, but the BIOS data area might
not have been initialized in that case.)

This change also means that there are now a few more fields
in the `struct mman`.

* [metal] VGA console can now show "screen of death" upon a crash

There is now a new function _klog_vga(), which can be called
by kprintf() to output system messages — e.g. information about
CPU exceptions — on the VGA screen.

* [metal] CPU exception handler now dumps cr2 value
* [metal] Add demo of program crash reporting w/ bare metal VGA TTY
* [metal] Reduce size of "screen of death" code
This commit is contained in:
tkchia 2022-10-06 20:36:15 +08:00 • committed by GitHub
parent 7822917fc2
commit d3efa47f81
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
13 changed files with 695 additions and 338 deletions
Download patch file Download diff file Expand all files Collapse all files

52
libc/vga/vga.internal.h
View file

@ -75,6 +75,16 @@
*/
#undef VGA_PERSNICKETY_STATUS
/* Flags which are passed to _StartTty(). */
#define kTtyAllocWcs 0x01 /* allocate Unicode character array
(if VGA_USE_WCS also defined) */
#define kTtyKlog 0x02 /* the system might be in an abnormal
state, & we are setting up the tty
to show system messages */
/**
* Flags for Tty::pr. These govern properties of individual character cells.
*/
#define kTtyFg 0x0001
#define kTtyBg 0x0002
#define kTtyBold 0x0004
@ -89,6 +99,10 @@
#define kTtyStrike 0x0800
#define kTtyConceal 0x1000
/**
* Flags for Tty::conf. These govern the current state of the teletypewriter
* as a whole.
*/
#define kTtyBell 0x001
#define kTtyRedzone 0x002
#define kTtyNocursor 0x004
@ -181,14 +195,15 @@ struct Tty {
* Canvas to draw into. In text modes, this is simply the frame buffer
* itself. In graphics modes, this should be separate from the frame
* buffer, & possibly allocated from main memory; we must arrange to
* update the frame buffer from the canvas every now & then. In general
* the canvas's pixel format — given by _TtyCanvasType() — may be
* different from the frame buffer's.
* update the frame buffer from the canvas every now & then.
*
* During normal operation, the canvas's pixel format is given by
* _TtyCanvasType(), & may be different from the frame buffer's.
*/
char *canvas;
/**
* Which portions of the canvas have been updated & should later be drawn
* to screen with tty->update().
* to screen with Tty::update().
*/
unsigned short updy1, updx1, updy2, updx2;
#ifdef VGA_USE_WCS
@ -219,6 +234,15 @@ forceinline unsigned char _TtyCanvasType(struct Tty *tty) {
return tty->type == PC_VIDEO_TEXT ? PC_VIDEO_TEXT : PC_VIDEO_BGRX8888;
}
forceinline unsigned short _TtyGetY(struct Tty *tty) {
return tty->y;
}
forceinline unsigned short _TtyGetX(struct Tty *tty) {
return tty->x;
}
/* Routines that implement normal graphical console output. */
void _TtyBgrxUpdate(struct Tty *);
void _TtyRgbxUpdate(struct Tty *);
void _TtyBgr565Update(struct Tty *);
@ -228,9 +252,25 @@ void _TtyGraphEraseLineCells(struct Tty *, size_t, size_t, size_t);
void _TtyGraphMoveLineCells(struct Tty *, size_t, size_t, size_t, size_t,
size_t);
/*
* Routines that implement emergency or system console output in graphical
* video modes.
*/
void _TtyKlog16Update(struct Tty *);
void _TtyKlog16DrawChar(struct Tty *, size_t, size_t, wchar_t);
void _TtyKlog16EraseLineCells(struct Tty *, size_t, size_t, size_t);
void _TtyKlog16MoveLineCells(struct Tty *, size_t, size_t, size_t, size_t,
size_t);
void _TtyKlog32Update(struct Tty *);
void _TtyKlog32DrawChar(struct Tty *, size_t, size_t, wchar_t);
void _TtyKlog32EraseLineCells(struct Tty *, size_t, size_t, size_t);
void _TtyKlog32MoveLineCells(struct Tty *, size_t, size_t, size_t, size_t,
size_t);
/* High-level teletypewriter routines. */
void _StartTty(struct Tty *, unsigned char, unsigned short, unsigned short,
unsigned short, unsigned short, unsigned short,
unsigned char, unsigned char, void *, bool);
unsigned char, unsigned char, void *, unsigned);
ssize_t _TtyRead(struct Tty *, void *, size_t);
ssize_t _TtyWrite(struct Tty *, const void *, size_t);
ssize_t _TtyWriteInput(struct Tty *, const void *, size_t);
@ -246,6 +286,8 @@ void _TtySetX(struct Tty *, unsigned short);
extern const uint8_t _vga_font_default_direct[95][13];
extern struct Tty _vga_tty;
void _vga_reinit(struct Tty *, unsigned short, unsigned short, unsigned);
void _klog_vga(const char *, size_t);
ssize_t sys_readv_vga(struct Fd *, const struct iovec *, int);
ssize_t sys_writev_vga(struct Fd *, const struct iovec *, int);