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author | fishsoupisgood <github@madingley.org> | 2019-04-29 01:17:54 +0100 |
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committer | fishsoupisgood <github@madingley.org> | 2019-05-27 03:43:43 +0100 |
commit | 3f2546b2ef55b661fd8dd69682b38992225e86f6 (patch) | |
tree | 65ca85f13617aee1dce474596800950f266a456c /roms/ipxe/src/arch/i386/image/com32.c | |
download | qemu-3f2546b2ef55b661fd8dd69682b38992225e86f6.tar.gz qemu-3f2546b2ef55b661fd8dd69682b38992225e86f6.tar.bz2 qemu-3f2546b2ef55b661fd8dd69682b38992225e86f6.zip |
Diffstat (limited to 'roms/ipxe/src/arch/i386/image/com32.c')
-rw-r--r-- | roms/ipxe/src/arch/i386/image/com32.c | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/roms/ipxe/src/arch/i386/image/com32.c b/roms/ipxe/src/arch/i386/image/com32.c new file mode 100644 index 00000000..c12ffb68 --- /dev/null +++ b/roms/ipxe/src/arch/i386/image/com32.c @@ -0,0 +1,292 @@ +/* + * 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., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +/** + * @file + * + * SYSLINUX COM32 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 <ipxe/uaccess.h> +#include <ipxe/image.h> +#include <ipxe/segment.h> +#include <ipxe/init.h> +#include <ipxe/io.h> + +/** + * Execute COMBOOT image + * + * @v image COM32 image + * @ret rc Return status code + */ +static int com32_exec_loop ( struct image *image ) { + struct memory_map memmap; + unsigned int i; + int state; + uint32_t avail_mem_top; + + state = rmsetjmp ( 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, avail_mem_top ); + + assert ( avail_mem_top != 0 ); + + com32_external_esp = phys_to_virt ( avail_mem_top ); + + /* Hook COMBOOT API interrupts */ + hook_comboot_interrupts(); + + /* 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 ); + + __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 */ + "sti\n\t" /* Enable interrupts */ + "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 */ + "cli\n\t" /* Disable interrupts */ + "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 ? + image->cmdline : "" ) ), + /* %6 */ "r" ( COM32_START_PHYS ) + : + "memory" ); + DBGC ( image, "COM32 %p: returned\n", image ); + break; + + case COMBOOT_EXIT: + DBGC ( image, "COM32 %p: exited\n", image ); + break; + + case COMBOOT_EXIT_RUN_KERNEL: + assert ( image->replacement ); + DBGC ( image, "COM32 %p: exited to run kernel %s\n", + image, image->replacement->name ); + break; + + case COMBOOT_EXIT_COMMAND: + DBGC ( image, "COM32 %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 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 com32_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 com32_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; +} + +/** + * Probe COM32 image + * + * @v image COM32 image + * @ret rc Return status code + */ +static int com32_probe ( struct image *image ) { + int rc; + + DBGC ( image, "COM32 %p: name '%s'\n", image, image->name ); + + /* Check if this is a COMBOOT image */ + if ( ( rc = com32_identify ( image ) ) != 0 ) { + return rc; + } + + return 0; +} + +/** + * Execute COMBOOT image + * + * @v image COM32 image + * @ret rc Return status code + */ +static int com32_exec ( struct image *image ) { + int rc; + + /* Load image */ + if ( ( rc = com32_load_image ( image ) ) != 0 ) { + return rc; + } + + /* Prepare bounce buffer segment */ + if ( ( rc = com32_prepare_bounce_buffer ( image ) ) != 0 ) { + return rc; + } + + return com32_exec_loop ( image ); +} + +/** SYSLINUX COM32 image type */ +struct image_type com32_image_type __image_type ( PROBE_NORMAL ) = { + .name = "COM32", + .probe = com32_probe, + .exec = com32_exec, +}; |