[comboot] Add COMBOOT and COM32 support

1 files changed, 275 insertions, 0 deletions

diff --git a/src/arch/i386/image/com32.c b/src/arch/i386/image/com32.c
new file mode 100644
index 000000000..da604625a
--- /dev/null
+++ b/src/arch/i386/image/com32.c
@@ -0,0 +1,275 @@
+/*
+ * 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 COM32 image format
+ *
+ */
+
+#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/memmap.h>
+
+struct image_type com32_image_type __image_type ( PROBE_NORMAL );
+
+/**
+ * Execute COMBOOT image
+ *
+ * @v image		COM32 image
+ * @ret rc		Return status code
+ */
+static int com32_exec ( struct image *image ) {
+	struct memory_map memmap;
+	unsigned int i;
+	int state;
+	uint32_t avail_mem_top;
+
+	state = setjmp ( comboot_return );
+
+	switch ( state ) {
+	case 0: /* First time through; invoke COM32 program */
+
+		/* Get memory map */
+		get_memmap ( &memmap );
+
+		/* Find end of block covering COM32 image loading area */
+		for ( i = 0, avail_mem_top = 0 ; i < memmap.count ; i++ ) {
+			if ( (memmap.regions[i].start <= COM32_START_PHYS) &&
+			     (memmap.regions[i].end > COM32_START_PHYS + image->len) ) {
+				avail_mem_top = memmap.regions[i].end;
+				break;
+			}
+		}
+
+		DBGC ( image, "COM32 %p: available memory top = 0x%x\n",
+			 image, (int)avail_mem_top );
+
+		assert ( avail_mem_top != 0 );
+
+		com32_external_esp = phys_to_virt ( avail_mem_top );
+
+		/* Hook COMBOOT API interrupts */
+		hook_comboot_interrupts( );
+
+		/* Temporarily de-register image, so that a "boot" command
+		 * doesn't throw us into an execution loop.  Hold a reference
+		 * to avoid the image's being freed.
+		 */
+		image_get ( image );
+		unregister_image ( image );
+
+		__asm__ __volatile__ (
+			"movl %%esp, (com32_internal_esp)\n\t" /* Save internal virtual address space ESP */
+			"movl (com32_external_esp), %%esp\n\t" /* Switch to COM32 ESP (top of available memory) */
+			"call _virt_to_phys\n\t"               /* Switch to flat physical address space */
+			"pushl %0\n\t"                         /* Pointer to CDECL helper function */
+			"pushl %1\n\t"                         /* Pointer to FAR call helper function */
+			"pushl %2\n\t"                         /* Size of low memory bounce buffer */
+			"pushl %3\n\t"                         /* Pointer to low memory bounce buffer */
+			"pushl %4\n\t"                         /* Pointer to INT call helper function */
+			"pushl %5\n\t"                         /* Pointer to the command line arguments */
+			"pushl $6\n\t"                         /* Number of additional arguments */
+			"call *%6\n\t"                         /* Execute image */
+			"call _phys_to_virt\n\t"               /* Switch back to internal virtual address space */
+			"movl (com32_internal_esp), %%esp\n\t" /* Switch back to internal stack */
+		:
+		:
+			/* %0 */ "r" ( virt_to_phys ( com32_cfarcall_wrapper ) ),
+			/* %1 */ "r" ( virt_to_phys ( com32_farcall_wrapper ) ),
+			/* %2 */ "r" ( get_fbms() * 1024 - (COM32_BOUNCE_SEG << 4) ),
+			/* %3 */ "i" ( COM32_BOUNCE_SEG << 4 ),
+			/* %4 */ "r" ( virt_to_phys ( com32_intcall_wrapper ) ),
+			/* %5 */ "r" ( virt_to_phys ( image->cmdline ) ),
+			/* %6 */ "r" ( COM32_START_PHYS )
+		:
+			"memory" );
+		break;
+
+	case COMBOOT_RETURN_RUN_KERNEL:
+		DBGC ( image, "COM32 %p: returned to run kernel...\n", image );
+		comboot_run_kernel ( );
+		break;
+
+	case COMBOOT_RETURN_EXIT:
+		break;
+
+	}
+
+	comboot_force_text_mode ( );
+
+	DBGC ( image, "COM32 %p returned\n", image );
+
+	/* Re-register image and return */
+	register_image ( image );
+	image_put ( image );
+
+	return 0;
+}
+
+/**
+ * Check image name extension
+ * 
+ * @v image		COM32 image
+ * @ret rc		Return status code
+ */
+static int com32_identify ( struct image *image ) {
+	const char *ext;
+	static const uint8_t magic[] = { 0xB8, 0xFF, 0x4C, 0xCD, 0x21 };
+	uint8_t buf[5];
+	
+	if ( image->len >= 5 ) {
+		/* Check for magic number
+		 * mov eax,21cd4cffh
+		 * B8 FF 4C CD 21
+		 */
+		copy_from_user ( buf, image->data, 0, sizeof(buf) );
+		if ( ! memcmp ( buf, magic, sizeof(buf) ) ) {
+			DBGC ( image, "COM32 %p: found magic number\n",
+			       image );
+			return 0;
+		}
+	}
+
+	/* Magic number not found; check filename extension */
+
+	ext = strrchr( image->name, '.' );
+
+	if ( ! ext ) {
+		DBGC ( image, "COM32 %p: no extension\n",
+		       image );
+		return -ENOEXEC;
+	}
+
+	++ext;
+
+	if ( strcasecmp( ext, "c32" ) ) {
+		DBGC ( image, "COM32 %p: unrecognized extension %s\n",
+		       image, ext );
+		return -ENOEXEC;
+	}
+
+	return 0;
+}
+
+
+/**
+ * Load COM32 image into memory
+ * @v image		COM32 image
+ * @ret rc		Return status code
+ */
+static int comboot_load_image ( struct image *image ) {
+	size_t filesz, memsz;
+	userptr_t buffer;
+	int rc;
+
+	filesz = image->len;
+	memsz = filesz;
+	buffer = phys_to_user ( COM32_START_PHYS );
+	if ( ( rc = prep_segment ( buffer, filesz, memsz ) ) != 0 ) {
+		DBGC ( image, "COM32 %p: could not prepare segment: %s\n",
+		       image, strerror ( rc ) );
+		return rc;
+	}
+
+	/* Copy image to segment */
+	memcpy_user ( buffer, 0, image->data, 0, filesz );
+
+	return 0;
+}
+
+/**
+ * Prepare COM32 low memory bounce buffer
+ * @v image		COM32 image
+ * @ret rc		Return status code
+ */
+static int comboot_prepare_bounce_buffer ( struct image * image ) {
+	unsigned int seg;
+	userptr_t seg_userptr;
+	size_t filesz, memsz;
+	int rc;
+
+	seg = COM32_BOUNCE_SEG;
+	seg_userptr = real_to_user ( seg, 0 );
+
+	/* Ensure the entire 64k segment is free */
+	memsz = 0xFFFF;
+	filesz = 0;
+
+	/* Prepare, verify, and load the real-mode segment */
+	if ( ( rc = prep_segment ( seg_userptr, filesz, memsz ) ) != 0 ) {
+		DBGC ( image, "COM32 %p: could not prepare bounce buffer segment: %s\n",
+		       image, strerror ( rc ) );
+		return rc;
+	}
+
+	return 0;
+}
+
+/**
+ * Load COM32 image into memory
+ *
+ * @v image		COM32 image
+ * @ret rc		Return status code
+ */
+static int com32_load ( struct image *image ) {
+	int rc;
+
+	DBGC ( image, "COM32 %p: name '%s', cmdline '%s'\n",
+	       image, image->name, image->cmdline );
+
+	/* Check if this is a COMBOOT image */
+	if ( ( rc = com32_identify ( image ) ) != 0 ) {
+		return rc;
+	}
+
+	/* This is a COM32 image, valid or otherwise */
+	if ( ! image->type )
+		image->type = &com32_image_type;
+
+	/* Load image */
+	if ( ( rc = comboot_load_image ( image ) ) != 0 ) {
+		return rc;
+	}
+
+	/* Prepare bounce buffer segment */
+	if ( ( rc = comboot_prepare_bounce_buffer ( image ) ) != 0 ) {
+		return rc;
+	}
+
+	return 0;
+}
+
+/** SYSLINUX COM32 image type */
+struct image_type com32_image_type __image_type ( PROBE_NORMAL ) = {
+	.name = "COM32",
+	.load = com32_load,
+	.exec = com32_exec,
+};