1 files changed, 322 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/gpxe/src/arch/i386/image/comboot.c b/contrib/syslinux-4.02/gpxe/src/arch/i386/image/comboot.c
new file mode 100644
index 0000000..a00b2b9
--- /dev/null
+++ b/contrib/syslinux-4.02/gpxe/src/arch/i386/image/comboot.c
@@ -0,0 +1,322 @@
+/*
+ * Copyright (C) 2008 Daniel Verkamp <daniel@drv.nu>.
+ *
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/**
+ * @file
+ *
+ * SYSLINUX COMBOOT (16-bit) image format
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <errno.h>
+#include <assert.h>
+#include <realmode.h>
+#include <basemem.h>
+#include <comboot.h>
+#include <gpxe/uaccess.h>
+#include <gpxe/image.h>
+#include <gpxe/segment.h>
+#include <gpxe/init.h>
+#include <gpxe/features.h>
+
+FEATURE ( FEATURE_IMAGE, "COMBOOT", DHCP_EB_FEATURE_COMBOOT, 1 );
+
+struct image_type comboot_image_type __image_type ( PROBE_NORMAL );
+
+/**
+ * COMBOOT PSP, copied to offset 0 of code segment
+ */
+struct comboot_psp {
+	/** INT 20 instruction, executed if COMBOOT image returns with RET */
+	uint16_t int20;
+	/** Segment of first non-free paragraph of memory */
+	uint16_t first_non_free_para;
+};
+
+/** Offset in PSP of command line */
+#define COMBOOT_PSP_CMDLINE_OFFSET 0x81
+
+/** Maximum length of command line in PSP
+ * (127 bytes minus space and CR) */
+#define COMBOOT_MAX_CMDLINE_LEN    125
+
+
+/**
+ * Copy command line to PSP
+ * 
+ * @v image		COMBOOT image
+ */
+static void comboot_copy_cmdline ( struct image * image, userptr_t seg_userptr ) {
+	const char *cmdline = ( image->cmdline ? image->cmdline : "" );
+	int cmdline_len = strlen ( cmdline );
+	if( cmdline_len > COMBOOT_MAX_CMDLINE_LEN )
+		cmdline_len = COMBOOT_MAX_CMDLINE_LEN;
+	uint8_t len_byte = cmdline_len;
+	char spc = ' ', cr = '\r';
+
+	/* Copy length to byte before command line */
+	copy_to_user ( seg_userptr, COMBOOT_PSP_CMDLINE_OFFSET - 1,
+	               &len_byte, 1 );
+
+	/* Command line starts with space */
+	copy_to_user ( seg_userptr,
+	               COMBOOT_PSP_CMDLINE_OFFSET,
+	               &spc, 1 );
+
+	/* Copy command line */
+	copy_to_user ( seg_userptr,
+	               COMBOOT_PSP_CMDLINE_OFFSET + 1,
+	               cmdline, cmdline_len );
+
+	/* Command line ends with CR */
+	copy_to_user ( seg_userptr,
+	               COMBOOT_PSP_CMDLINE_OFFSET + cmdline_len + 1,
+	               &cr, 1 );
+}
+
+/**
+ * Initialize PSP
+ * 
+ * @v image		COMBOOT image
+ * @v seg_userptr	segment to initialize
+ */
+static void comboot_init_psp ( struct image * image, userptr_t seg_userptr ) {
+	struct comboot_psp psp;
+
+	/* Fill PSP */
+
+	/* INT 20h instruction, byte order reversed */
+	psp.int20 = 0x20CD;
+
+	/* get_fbms() returns BIOS free base memory counter, which is in
+	 * kilobytes; x * 1024 / 16 == x * 64 == x << 6 */
+	psp.first_non_free_para = get_fbms() << 6;
+
+	DBGC ( image, "COMBOOT %p: first non-free paragraph = 0x%x\n",
+	       image, psp.first_non_free_para );
+
+	/* Copy the PSP to offset 0 of segment.
+	 * The rest of the PSP was already zeroed by
+	 * comboot_prepare_segment. */
+	copy_to_user ( seg_userptr, 0, &psp, sizeof( psp ) );
+
+	/* Copy the command line to the PSP */
+	comboot_copy_cmdline ( image, seg_userptr );
+}
+
+/**
+ * Execute COMBOOT image
+ *
+ * @v image		COMBOOT image
+ * @ret rc		Return status code
+ */
+static int comboot_exec ( struct image *image ) {
+	userptr_t seg_userptr = real_to_user ( COMBOOT_PSP_SEG, 0 );
+	int state;
+
+	state = rmsetjmp ( comboot_return );
+
+	switch ( state ) {
+	case 0: /* First time through; invoke COMBOOT program */
+
+		/* Initialize PSP */
+		comboot_init_psp ( image, seg_userptr );
+
+		/* Hook COMBOOT API interrupts */
+		hook_comboot_interrupts();
+
+		DBGC ( image, "executing 16-bit COMBOOT image at %4x:0100\n",
+		       COMBOOT_PSP_SEG );
+
+		/* Unregister image, so that a "boot" command doesn't
+		 * throw us into an execution loop.  We never
+		 * reregister ourselves; COMBOOT images expect to be
+		 * removed on exit.
+		 */
+		unregister_image ( image );
+
+		/* Store stack segment at 0x38 and stack pointer at 0x3A
+		 * in the PSP and jump to the image */
+		__asm__ __volatile__ (
+		    REAL_CODE ( /* Save return address with segment on old stack */
+				    "popw %%ax\n\t"
+				    "pushw %%cs\n\t"
+				    "pushw %%ax\n\t"
+				    /* Set DS=ES=segment with image */
+				    "movw %w0, %%ds\n\t"
+				    "movw %w0, %%es\n\t"
+				    /* Set SS:SP to new stack (end of image segment) */
+				    "movw %w0, %%ss\n\t"
+				    "xor %%sp, %%sp\n\t"
+				    "pushw $0\n\t"
+				    "pushw %w0\n\t"
+				    "pushw $0x100\n\t"
+				    /* Zero registers (some COM files assume GP regs are 0) */
+				    "xorw %%ax, %%ax\n\t"
+				    "xorw %%bx, %%bx\n\t"
+				    "xorw %%cx, %%cx\n\t"
+				    "xorw %%dx, %%dx\n\t"
+				    "xorw %%si, %%si\n\t"
+				    "xorw %%di, %%di\n\t"
+				    "xorw %%bp, %%bp\n\t"
+				    "lret\n\t" )
+					 : : "r" ( COMBOOT_PSP_SEG ) : "eax" );
+		DBGC ( image, "COMBOOT %p: returned\n", image );
+		break;
+
+	case COMBOOT_EXIT:
+		DBGC ( image, "COMBOOT %p: exited\n", image );
+		break;
+
+	case COMBOOT_EXIT_RUN_KERNEL:
+		DBGC ( image, "COMBOOT %p: exited to run kernel %p\n",
+		       image, comboot_replacement_image );
+		image->replacement = comboot_replacement_image;
+		comboot_replacement_image = NULL;
+		image_autoload ( image->replacement );
+		break;
+
+	case COMBOOT_EXIT_COMMAND:
+		DBGC ( image, "COMBOOT %p: exited after executing command\n",
+		       image );
+		break;
+
+	default:
+		assert ( 0 );
+		break;
+	}
+
+	unhook_comboot_interrupts();
+	comboot_force_text_mode();
+
+	return 0;
+}
+
+/**
+ * Check image name extension
+ * 
+ * @v image		COMBOOT image
+ * @ret rc		Return status code
+ */
+static int comboot_identify ( struct image *image ) {
+	const char *ext;
+
+	ext = strrchr( image->name, '.' );
+
+	if ( ! ext ) {
+		DBGC ( image, "COMBOOT %p: no extension\n",
+		       image );
+		return -ENOEXEC;
+	}
+
+	++ext;
+
+	if ( strcasecmp( ext, "com" ) && strcasecmp( ext, "cbt" ) ) {
+		DBGC ( image, "COMBOOT %p: unrecognized extension %s\n",
+		       image, ext );
+		return -ENOEXEC;
+	}
+
+	return 0;
+}
+
+/**
+ * Load COMBOOT image into memory, preparing a segment and returning it
+ * @v image		COMBOOT image
+ * @ret rc		Return status code
+ */
+static int comboot_prepare_segment ( struct image *image )
+{
+	userptr_t seg_userptr;
+	size_t filesz, memsz;
+	int rc;
+
+	/* Load image in segment */
+	seg_userptr = real_to_user ( COMBOOT_PSP_SEG, 0 );
+
+	/* Allow etra 0x100 bytes before image for PSP */
+	filesz = image->len + 0x100; 
+
+	/* Ensure the entire 64k segment is free */
+	memsz = 0xFFFF;
+
+	/* Prepare, verify, and load the real-mode segment */
+	if ( ( rc = prep_segment ( seg_userptr, filesz, memsz ) ) != 0 ) {
+		DBGC ( image, "COMBOOT %p: could not prepare segment: %s\n",
+		       image, strerror ( rc ) );
+		return rc;
+	}
+
+	/* Zero PSP */
+	memset_user ( seg_userptr, 0, 0, 0x100 );
+
+	/* Copy image to segment:0100 */
+	memcpy_user ( seg_userptr, 0x100, image->data, 0, image->len );
+
+	return 0;
+}
+
+/**
+ * Load COMBOOT image into memory
+ *
+ * @v image		COMBOOT image
+ * @ret rc		Return status code
+ */
+static int comboot_load ( struct image *image ) {
+	int rc;
+
+	DBGC ( image, "COMBOOT %p: name '%s'\n",
+	       image, image->name );
+
+	/* Check if this is a COMBOOT image */
+	if ( ( rc = comboot_identify ( image ) ) != 0 ) {
+		
+		return rc;
+	}
+
+	/* This is a 16-bit COMBOOT image, valid or otherwise */
+	if ( ! image->type )
+		image->type = &comboot_image_type;
+	
+	/* Sanity check for filesize */
+	if( image->len >= 0xFF00 ) {
+		DBGC( image, "COMBOOT %p: image too large\n",
+		      image );
+		return -ENOEXEC;
+	}
+
+	/* Prepare segment and load image */
+	if ( ( rc = comboot_prepare_segment ( image ) ) != 0 ) {
+		return rc;
+	}
+
+	return 0;
+}
+
+/** SYSLINUX COMBOOT (16-bit) image type */
+struct image_type comboot_image_type __image_type ( PROBE_NORMAL ) = {
+	.name = "COMBOOT",
+	.load = comboot_load,
+	.exec = comboot_exec,
+};