bios_console.c

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/*
 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <assert.h>
#include <realmode.h>
#include <bios.h>
#include <biosint.h>
#include <ipxe/console.h>
#include <ipxe/ansiesc.h>
#include <ipxe/keys.h>
#include <ipxe/keymap.h>
#include <ipxe/init.h>
#include <config/console.h>

#define ATTR_BOLD               0x08

#define ATTR_FCOL_MASK          0x07
#define ATTR_FCOL_BLACK         0x00
#define ATTR_FCOL_BLUE          0x01
#define ATTR_FCOL_GREEN         0x02
#define ATTR_FCOL_CYAN          0x03
#define ATTR_FCOL_RED           0x04
#define ATTR_FCOL_MAGENTA       0x05
#define ATTR_FCOL_YELLOW        0x06
#define ATTR_FCOL_WHITE         0x07

#define ATTR_BLINK              0x80

#define ATTR_BCOL_MASK          0x70
#define ATTR_BCOL_BLACK         0x00
#define ATTR_BCOL_BLUE          0x10
#define ATTR_BCOL_GREEN         0x20
#define ATTR_BCOL_CYAN          0x30
#define ATTR_BCOL_RED           0x40
#define ATTR_BCOL_MAGENTA       0x50
#define ATTR_BCOL_YELLOW        0x60
#define ATTR_BCOL_WHITE         0x70

#define ATTR_DEFAULT            ATTR_FCOL_WHITE

/** Maximum keycode subject to remapping
 *
 * This allows us to avoid remapping the numeric keypad, which is
 * necessary for keyboard layouts such as "fr" that swap the shifted
 * and unshifted digit keys.
 */
#define SCANCODE_RSHIFT         0x36

/** Scancode for the "non-US \ and |" key
 *
 * This is the key that appears between Left Shift and Z on non-US
 * keyboards.
 */
#define SCANCODE_NON_US         0x56

/* Set default console usage if applicable */
#if ! ( defined ( CONSOLE_PCBIOS ) && CONSOLE_EXPLICIT ( CONSOLE_PCBIOS ) )
#undef CONSOLE_PCBIOS
#define CONSOLE_PCBIOS ( CONSOLE_USAGE_ALL & ~CONSOLE_USAGE_LOG )
#endif

/** Current character attribute */
static unsigned int bios_attr = ATTR_DEFAULT;

/** Keypress injection lock */
static uint8_t __text16 ( bios_inject_lock );
#define bios_inject_lock __use_text16 ( bios_inject_lock )

/** Vector for chaining to other INT 16 handlers */
static struct segoff __text16 ( int16_vector );
#define int16_vector __use_text16 ( int16_vector )

/** Assembly wrapper */
extern void int16_wrapper ( void );

/**
 * Handle ANSI CUP (cursor position)
 *
 * @v ctx               ANSI escape sequence context
 * @v count             Parameter count
 * @v params[0]         Row (1 is top)
 * @v params[1]         Column (1 is left)
 */
static void bios_handle_cup ( struct ansiesc_context *ctx __unused,
                              unsigned int count __unused, int params[] ) {
        int cx = ( params[1] - 1 );
        int cy = ( params[0] - 1 );

        if ( cx < 0 )
                cx = 0;
        if ( cy < 0 )
                cy = 0;

        __asm__ __volatile__ ( REAL_CODE ( "int $0x10\n\t" )
                               : : "a" ( 0x0200 ), "b" ( 1 ),
                                   "d" ( ( cy << 8 ) | cx ) );
}

/**
 * Handle ANSI ED (erase in page)
 *
 * @v ctx               ANSI escape sequence context
 * @v count             Parameter count
 * @v params[0]         Region to erase
 */
static void bios_handle_ed ( struct ansiesc_context *ctx __unused,
                             unsigned int count __unused,
                             int params[] __unused ) {
        /* We assume that we always clear the whole screen */
        assert ( params[0] == ANSIESC_ED_ALL );

        __asm__ __volatile__ ( REAL_CODE ( "int $0x10\n\t" )
                               : : "a" ( 0x0600 ), "b" ( bios_attr << 8 ),
                                   "c" ( 0 ),
                                   "d" ( ( ( console_height - 1 ) << 8 ) |
                                         ( console_width - 1 ) ) );
}

/**
 * Handle ANSI SGR (set graphics rendition)
 *
 * @v ctx               ANSI escape sequence context
 * @v count             Parameter count
 * @v params            List of graphic rendition aspects
 */
static void bios_handle_sgr ( struct ansiesc_context *ctx __unused,
                              unsigned int count, int params[] ) {
        static const uint8_t bios_attr_fcols[10] = {
                ATTR_FCOL_BLACK, ATTR_FCOL_RED, ATTR_FCOL_GREEN,
                ATTR_FCOL_YELLOW, ATTR_FCOL_BLUE, ATTR_FCOL_MAGENTA,
                ATTR_FCOL_CYAN, ATTR_FCOL_WHITE,
                ATTR_FCOL_WHITE, ATTR_FCOL_WHITE /* defaults */
        };
        static const uint8_t bios_attr_bcols[10] = {
                ATTR_BCOL_BLACK, ATTR_BCOL_RED, ATTR_BCOL_GREEN,
                ATTR_BCOL_YELLOW, ATTR_BCOL_BLUE, ATTR_BCOL_MAGENTA,
                ATTR_BCOL_CYAN, ATTR_BCOL_WHITE,
                ATTR_BCOL_BLACK, ATTR_BCOL_BLACK /* defaults */
        };
        unsigned int i;
        int aspect;

        for ( i = 0 ; i < count ; i++ ) {
                aspect = params[i];
                if ( aspect == 0 ) {
                        bios_attr = ATTR_DEFAULT;
                } else if ( aspect == 1 ) {
                        bios_attr |= ATTR_BOLD;
                } else if ( aspect == 5 ) {
                        bios_attr |= ATTR_BLINK;
                } else if ( aspect == 22 ) {
                        bios_attr &= ~ATTR_BOLD;
                } else if ( aspect == 25 ) {
                        bios_attr &= ~ATTR_BLINK;
                } else if ( ( aspect >= 30 ) && ( aspect <= 39 ) ) {
                        bios_attr &= ~ATTR_FCOL_MASK;
                        bios_attr |= bios_attr_fcols[ aspect - 30 ];
                } else if ( ( aspect >= 40 ) && ( aspect <= 49 ) ) {
                        bios_attr &= ~ATTR_BCOL_MASK;
                        bios_attr |= bios_attr_bcols[ aspect - 40 ];
                }
        }
}

/**
 * Handle ANSI DECTCEM set (show cursor)
 *
 * @v ctx               ANSI escape sequence context
 * @v count             Parameter count
 * @v params            List of graphic rendition aspects
 */
static void bios_handle_dectcem_set ( struct ansiesc_context *ctx __unused,
                                      unsigned int count __unused,
                                      int params[] __unused ) {
        uint8_t height;

        /* Get character height */
        get_real ( height, BDA_SEG, BDA_CHAR_HEIGHT );

        __asm__ __volatile__ ( REAL_CODE ( "int $0x10\n\t" )
                               : : "a" ( 0x0100 ),
                                   "c" ( ( ( height - 2 ) << 8 ) |
                                         ( height - 1 ) ) );
}

/**
 * Handle ANSI DECTCEM reset (hide cursor)
 *
 * @v ctx               ANSI escape sequence context
 * @v count             Parameter count
 * @v params            List of graphic rendition aspects
 */
static void bios_handle_dectcem_reset ( struct ansiesc_context *ctx __unused,
                                        unsigned int count __unused,
                                        int params[] __unused ) {

        __asm__ __volatile__ ( REAL_CODE ( "int $0x10\n\t" )
                               : : "a" ( 0x0100 ), "c" ( 0x2000 ) );
}

/** BIOS console ANSI escape sequence handlers */
static struct ansiesc_handler bios_ansiesc_handlers[] = {
        { ANSIESC_CUP, bios_handle_cup },
        { ANSIESC_ED, bios_handle_ed },
        { ANSIESC_SGR, bios_handle_sgr },
        { ANSIESC_DECTCEM_SET, bios_handle_dectcem_set },
        { ANSIESC_DECTCEM_RESET, bios_handle_dectcem_reset },
        { 0, NULL }
};

/** BIOS console ANSI escape sequence context */
static struct ansiesc_context bios_ansiesc_ctx = {
        .handlers = bios_ansiesc_handlers,
};

/**
 * Print a character to BIOS console
 *
 * @v character         Character to be printed
 */
static void bios_putchar ( int character ) {
        int discard_a, discard_b, discard_c;

        /* Intercept ANSI escape sequences */
        character = ansiesc_process ( &bios_ansiesc_ctx, character );
        if ( character < 0 )
                return;

        /* Print character with attribute */
        __asm__ __volatile__ ( REAL_CODE ( "pushl %%ebp\n\t" /* gcc bug */
                                           /* Skip non-printable characters */
                                           "cmpb $0x20, %%al\n\t"
                                           "jb 1f\n\t"
                                           /* Read attribute */
                                           "movb %%al, %%cl\n\t"
                                           "movb $0x08, %%ah\n\t"
                                           "int $0x10\n\t"
                                           "xchgb %%al, %%cl\n\t"
                                           /* Skip if attribute matches */
                                           "cmpb %%ah, %%bl\n\t"
                                           "je 1f\n\t"
                                           /* Set attribute */
                                           "movw $0x0001, %%cx\n\t"
                                           "movb $0x09, %%ah\n\t"
                                           "int $0x10\n\t"
                                           "\n1:\n\t"
                                           /* Print character */
                                           "xorw %%bx, %%bx\n\t"
                                           "movb $0x0e, %%ah\n\t"
                                           "int $0x10\n\t"
                                           "popl %%ebp\n\t" /* gcc bug */ )
                               : "=a" ( discard_a ), "=b" ( discard_b ),
                                 "=c" ( discard_c )
                               : "a" ( character ), "b" ( bios_attr ) );
}

/**
 * Pointer to current ANSI output sequence
 *
 * While we are in the middle of returning an ANSI sequence for a
 * special key, this will point to the next character to return.  When
 * not in the middle of such a sequence, this will point to a NUL
 * (note: not "will be NULL").
 */
static const char *bios_ansi_input = "";

/** A BIOS key */
struct bios_key {
        /** Scancode */
        uint8_t scancode;
        /** Relative key value */
        uint16_t rkey;
} __attribute__ (( packed ));

/**
 * Define a BIOS key mapping
 *
 * @v scancode          Scancode
 * @v key               iPXE key code
 * @v bioskey           BIOS key mapping
 */
#define BIOS_KEY( scancode, key ) { scancode, KEY_REL ( key ) }

/** Mapping from BIOS scan codes to iPXE key codes */
static const struct bios_key bios_keys[] = {
        BIOS_KEY ( 0x53, KEY_DC ),
        BIOS_KEY ( 0x48, KEY_UP ),
        BIOS_KEY ( 0x50, KEY_DOWN ),
        BIOS_KEY ( 0x4b, KEY_LEFT ),
        BIOS_KEY ( 0x4d, KEY_RIGHT ),
        BIOS_KEY ( 0x47, KEY_HOME ),
        BIOS_KEY ( 0x4f, KEY_END ),
        BIOS_KEY ( 0x49, KEY_PPAGE ),
        BIOS_KEY ( 0x51, KEY_NPAGE ),
        BIOS_KEY ( 0x3f, KEY_F5 ),
        BIOS_KEY ( 0x40, KEY_F6 ),
        BIOS_KEY ( 0x41, KEY_F7 ),
        BIOS_KEY ( 0x42, KEY_F8 ),
        BIOS_KEY ( 0x43, KEY_F9 ),
        BIOS_KEY ( 0x44, KEY_F10 ),
        BIOS_KEY ( 0x85, KEY_F11 ),
        BIOS_KEY ( 0x86, KEY_F12 ),
};

/**
 * Get ANSI escape sequence corresponding to BIOS scancode
 *
 * @v scancode          BIOS scancode
 * @ret ansi_seq        ANSI escape sequence, if any, otherwise NULL
 */
static const char * bios_ansi_seq ( unsigned int scancode ) {
        static char buf[ 5 /* "[" + two digits + terminator + NUL */ ];
        unsigned int rkey;
        unsigned int terminator;
        unsigned int n;
        unsigned int i;
        char *tmp = buf;

        /* Construct ANSI escape sequence for scancode, if known */
        for ( i = 0 ; i < ( sizeof ( bios_keys ) /
                            sizeof ( bios_keys[0] ) ) ; i++ ) {

                /* Look for matching scancode */
                if ( bios_keys[i].scancode != scancode )
                        continue;

                /* Construct escape sequence */
                rkey = bios_keys[i].rkey;
                n = KEY_ANSI_N ( rkey );
                terminator = KEY_ANSI_TERMINATOR ( rkey );
                *(tmp++) = '[';
                if ( n )
                        tmp += sprintf ( tmp, "%d", n );
                *(tmp++) = terminator;
                *(tmp++) = '\0';
                assert ( tmp <= &buf[ sizeof ( buf ) ] );
                return buf;
        }

        DBG ( "Unrecognised BIOS scancode %02x\n", scancode );
        return NULL;
}

/**
 * Get character from BIOS console
 *
 * @ret character       Character read from console
 */
static int bios_getchar ( void ) {
        uint16_t keypress;
        uint8_t kb0;
        uint8_t kb2;
        unsigned int scancode;
        unsigned int character;
        const char *ansi_seq;

        /* If we are mid-sequence, pass out the next byte */
        if ( ( character = *bios_ansi_input ) ) {
                bios_ansi_input++;
                return character;
        }

        /* Do nothing if injection is in progress */
        if ( bios_inject_lock )
                return 0;

        /* Read character from real BIOS console */
        bios_inject_lock++;
        __asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
                                           "int $0x16\n\t"
                                           "cli\n\t" )
                               : "=a" ( keypress )
                               : "a" ( 0x1000 ), "m" ( bios_inject_lock ) );
        bios_inject_lock--;
        scancode = ( keypress >> 8 );
        character = ( keypress & 0xff );
        get_real ( kb0, BDA_SEG, BDA_KB0 );
        get_real ( kb2, BDA_SEG, BDA_KB2 );

        /* If it's a normal character, map (if applicable) and return it */
        if ( character && ( character < 0x80 ) ) {

                /* Handle special scancodes */
                if ( scancode == SCANCODE_NON_US ) {
                        /* Treat as "\|" with high bit set */
                        character |= KEYMAP_PSEUDO;
                } else if ( scancode >= SCANCODE_RSHIFT ) {
                        /* Non-remappable scancode (e.g. numeric keypad) */
                        return character;
                }

                /* Apply modifiers */
                if ( kb0 & BDA_KB0_CTRL )
                        character |= KEYMAP_CTRL;
                if ( kb0 & BDA_KB0_CAPSLOCK )
                        character |= KEYMAP_CAPSLOCK_REDO;
                if ( kb2 & BDA_KB2_RALT )
                        character |= KEYMAP_ALTGR;

                /* Treat LShift+RShift as AltGr since many BIOSes will
                 * not return ASCII characters when AltGr is pressed.
                 */
                if ( ( kb0 & ( BDA_KB0_LSHIFT | BDA_KB0_RSHIFT ) ) ==
                     ( BDA_KB0_LSHIFT | BDA_KB0_RSHIFT ) ) {
                        character |= KEYMAP_ALTGR;
                }

                /* Map and return */
                return key_remap ( character );
        }

        /* Otherwise, check for a special key that we know about */
        if ( ( ansi_seq = bios_ansi_seq ( keypress >> 8 ) ) ) {
                /* Start of escape sequence: return ESC (0x1b) */
                bios_ansi_input = ansi_seq;
                return 0x1b;
        }

        return 0;
}

/**
 * Check for character ready to read from BIOS console
 *
 * @ret True            Character available to read
 * @ret False           No character available to read
 */
static int bios_iskey ( void ) {
        unsigned int discard_a;
        unsigned int flags;

        /* If we are mid-sequence, we are always ready */
        if ( *bios_ansi_input )
                return 1;

        /* Do nothing if injection is in progress */
        if ( bios_inject_lock )
                return 0;

        /* Otherwise check the real BIOS console */
        bios_inject_lock++;
        __asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
                                           "int $0x16\n\t"
                                           "pushfw\n\t"
                                           "popw %w0\n\t"
                                           "cli\n\t" )
                               : "=R" ( flags ), "=a" ( discard_a )
                               : "a" ( 0x1100 ), "m" ( bios_inject_lock ) );
        bios_inject_lock--;
        return ( ! ( flags & ZF ) );
}

/** BIOS console */
struct console_driver bios_console __console_driver = {
        .putchar = bios_putchar,
        .getchar = bios_getchar,
        .iskey = bios_iskey,
        .usage = CONSOLE_PCBIOS,
};

/**
 * Inject keypresses
 *
 * @v ix86              Registers as passed to INT 16
 */
static __asmcall __used void bios_inject ( struct i386_all_regs *ix86 ) {
        unsigned int discard_a;
        unsigned int scancode;
        unsigned int rkey;
        unsigned int i;
        uint16_t keypress;
        int key;

        /* If this is a blocking call, then loop until the
         * non-blocking variant of the call indicates that a keypress
         * is available.  Do this without acquiring the injection
         * lock, so that injection may take place.
         */
        if ( ( ix86->regs.ah & ~0x10 ) == 0x00 ) {
                __asm__ __volatile__ ( REAL_CODE ( "sti\n\t"
                                                   "\n1:\n\t"
                                                   "pushw %%ax\n\t"
                                                   "int $0x16\n\t"
                                                   "popw %%ax\n\t"
                                                   "jc 2f\n\t"
                                                   "jz 1b\n\t"
                                                   "\n2:\n\t"
                                                   "cli\n\t" )
                                       : "=a" ( discard_a )
                                       : "a" ( ix86->regs.eax | 0x0100 ),
                                         "m" ( bios_inject_lock ) );
        }

        /* Acquire injection lock */
        bios_inject_lock++;

        /* Check for keypresses */
        if ( iskey() ) {

                /* Get key */
                key = getkey ( 0 );

                /* Reverse internal CR->LF mapping */
                if ( key == '\n' )
                        key = '\r';

                /* Convert to keypress */
                keypress = ( ( key << 8 ) | key );

                /* Handle special keys */
                if ( key >= KEY_MIN ) {
                        rkey = KEY_REL ( key );
                        for ( i = 0 ; i < ( sizeof ( bios_keys ) /
                                            sizeof ( bios_keys[0] ) ) ; i++ ) {
                                if ( bios_keys[i].rkey == rkey ) {
                                        scancode = bios_keys[i].scancode;
                                        keypress = ( scancode << 8 );
                                        break;
                                }
                        }
                }

                /* Inject keypress */
                DBGC ( &bios_console, "BIOS injecting keypress %04x\n",
                       keypress );
                __asm__ __volatile__ ( REAL_CODE ( "int $0x16\n\t" )
                                       : "=a" ( discard_a )
                                       : "a" ( 0x0500 ), "c" ( keypress ),
                                         "m" ( bios_inject_lock ) );
        }

        /* Release injection lock */
        bios_inject_lock--;
}

/**
 * Start up keypress injection
 *
 */
static void bios_inject_startup ( void ) {

        /* Assembly wrapper to call bios_inject() */
        __asm__ __volatile__ (
                TEXT16_CODE ( "\nint16_wrapper:\n\t"
                              "pushfw\n\t"
                              "cmpb $0, %%cs:bios_inject_lock\n\t"
                              "jnz 1f\n\t"
                              VIRT_CALL ( bios_inject )
                              "\n1:\n\t"
                              "popfw\n\t"
                              "ljmp *%%cs:int16_vector\n\t" ) : );

        /* Hook INT 16 */
        hook_bios_interrupt ( 0x16, ( ( intptr_t ) int16_wrapper ),
                              &int16_vector );
}

/**
 * Shut down keypress injection
 *
 * @v booting           System is shutting down for OS boot
 */
static void bios_inject_shutdown ( int booting __unused ) {

        /* Unhook INT 16 */
        unhook_bios_interrupt ( 0x16, ( ( intptr_t ) int16_wrapper ),
                                &int16_vector );
}

/** Keypress injection startup function */
struct startup_fn bios_inject_startup_fn __startup_fn ( STARTUP_NORMAL ) = {
        .name = "bios_inject",
        .startup = bios_inject_startup,
        .shutdown = bios_inject_shutdown,
};