/*- * Copyright (c) 2014 Roger Pau Monné * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * This multiboot implementation only implements a subset of the full * multiboot specification in order to be able to boot Xen and a * FreeBSD Dom0. Trying to use it to boot other multiboot compliant * kernels will most surely fail. * * The full multiboot specification can be found here: * http://www.gnu.org/software/grub/manual/multiboot/multiboot.html */ #include #include #include #include #include #define _MACHINE_ELF_WANT_32BIT #include #include #include #include #include "bootstrap.h" #include "multiboot.h" #include "libi386.h" #include #define MULTIBOOT_SUPPORTED_FLAGS \ (MULTIBOOT_PAGE_ALIGN|MULTIBOOT_MEMORY_INFO) #define NUM_MODULES 2 extern int elf32_loadfile_raw(char *filename, uint64_t dest, struct preloaded_file **result, int multiboot); extern int elf64_load_modmetadata(struct preloaded_file *fp, uint64_t dest); extern int elf64_obj_loadfile(char *filename, uint64_t dest, struct preloaded_file **result); static int multiboot_loadfile(char *, uint64_t, struct preloaded_file **); static int multiboot_exec(struct preloaded_file *); static int multiboot_obj_loadfile(char *, uint64_t, struct preloaded_file **); static int multiboot_obj_exec(struct preloaded_file *fp); struct file_format multiboot = { multiboot_loadfile, multiboot_exec }; struct file_format multiboot_obj = { multiboot_obj_loadfile, multiboot_obj_exec }; extern void multiboot_tramp(); static const char mbl_name[] = "FreeBSD Loader"; static int multiboot_loadfile(char *filename, uint64_t dest, struct preloaded_file **result) { uint32_t *magic; int i, error; caddr_t header_search; ssize_t search_size; int fd; struct multiboot_header *header; char *cmdline; /* * Read MULTIBOOT_SEARCH size in order to search for the * multiboot magic header. */ if (filename == NULL) return (EFTYPE); if ((fd = open(filename, O_RDONLY)) == -1) return (errno); header_search = malloc(MULTIBOOT_SEARCH); if (header_search == NULL) { close(fd); return (ENOMEM); } search_size = read(fd, header_search, MULTIBOOT_SEARCH); magic = (uint32_t *)header_search; header = NULL; for (i = 0; i < (search_size / sizeof(uint32_t)); i++) { if (magic[i] == MULTIBOOT_HEADER_MAGIC) { header = (struct multiboot_header *)&magic[i]; break; } } if (header == NULL) { error = EFTYPE; goto out; } /* Valid multiboot header has been found, validate checksum */ if (header->magic + header->flags + header->checksum != 0) { printf( "Multiboot checksum failed, magic: 0x%x flags: 0x%x checksum: 0x%x\n", header->magic, header->flags, header->checksum); error = EFTYPE; goto out; } if ((header->flags & ~MULTIBOOT_SUPPORTED_FLAGS) != 0) { printf("Unsupported multiboot flags found: 0x%x\n", header->flags); error = EFTYPE; goto out; } error = elf32_loadfile_raw(filename, dest, result, 1); if (error != 0) { printf( "elf32_loadfile_raw failed: %d unable to load multiboot kernel\n", error); goto out; } /* * f_addr is already aligned to PAGE_SIZE, make sure * f_size it's also aligned so when the modules are loaded * they are aligned to PAGE_SIZE. */ (*result)->f_size = roundup((*result)->f_size, PAGE_SIZE); out: free(header_search); close(fd); return (error); } static int multiboot_exec(struct preloaded_file *fp) { vm_offset_t modulep, kernend, entry; struct file_metadata *md; Elf_Ehdr *ehdr; struct multiboot_info *mb_info = NULL; struct multiboot_mod_list *mb_mod = NULL; char *cmdline = NULL; size_t len; int error, mod_num; struct xen_header header; _Static_assert(sizeof(header) <= PAGE_SIZE, "header too large for page"); /* * Don't pass the memory size found by the bootloader, the memory * available to Dom0 will be lower than that. */ unsetenv("smbios.memory.enabled"); /* Allocate the multiboot struct and fill the basic details. */ mb_info = malloc(sizeof(struct multiboot_info)); if (mb_info == NULL) { error = ENOMEM; goto error; } bzero(mb_info, sizeof(struct multiboot_info)); mb_info->flags = MULTIBOOT_INFO_MEMORY|MULTIBOOT_INFO_BOOT_LOADER_NAME; mb_info->mem_lower = bios_basemem / 1024; mb_info->mem_upper = bios_extmem / 1024; mb_info->boot_loader_name = VTOP(mbl_name); /* Set the Xen command line. */ if (fp->f_args == NULL) { /* Add the Xen command line if it is set. */ cmdline = getenv("xen_cmdline"); if (cmdline != NULL) { fp->f_args = strdup(cmdline); if (fp->f_args == NULL) { error = ENOMEM; goto error; } } } if (fp->f_args != NULL) { len = strlen(fp->f_name) + 1 + strlen(fp->f_args) + 1; cmdline = malloc(len); if (cmdline == NULL) { error = ENOMEM; goto error; } snprintf(cmdline, len, "%s %s", fp->f_name, fp->f_args); mb_info->cmdline = VTOP(cmdline); mb_info->flags |= MULTIBOOT_INFO_CMDLINE; } /* Find the entry point of the Xen kernel and save it for later */ if ((md = file_findmetadata(fp, MODINFOMD_ELFHDR)) == NULL) { printf("Unable to find %s entry point\n", fp->f_name); error = EINVAL; goto error; } ehdr = (Elf_Ehdr *)&(md->md_data); entry = ehdr->e_entry & 0xffffff; /* * Prepare the multiboot module list, Xen assumes the first * module is the Dom0 kernel, and the second one is the initramfs. * This is not optimal for FreeBSD, that doesn't have a initramfs * but instead loads modules dynamically and creates the metadata * info on-the-fly. * * As expected, the first multiboot module is going to be the * FreeBSD kernel loaded as a raw file. The second module is going * to contain the metadata info and the loaded modules. * * There's a small header prefixed in the second module that contains * some information required to calculate the relocated address of * modulep based on the original offset of modulep from the start of * the module address. Note other fields might be added to this header * if required. * * Native layout: * fp->f_addr + fp->f_size * +---------+----------------+------------+ * | | | | * | Kernel | Modules | Metadata | * | | | | * +---------+----------------+------------+ * fp->f_addr modulep kernend * * Xen dom0 layout: * fp->f_addr fp->f_addr + fp->f_size * +---------+------------+----------------+------------+ * | | | | | * | Kernel | xen_header | Modules | Metadata | * | | | | | * +---------+------------+----------------+------------+ * modulep kernend * \________/\__________________________________________/ * module 0 module 1 */ fp = file_findfile(NULL, "elf kernel"); if (fp == NULL) { printf("No FreeBSD kernel provided, aborting\n"); error = EINVAL; goto error; } mb_mod = malloc(sizeof(struct multiboot_mod_list) * NUM_MODULES); if (mb_mod == NULL) { error = ENOMEM; goto error; } bzero(mb_mod, sizeof(struct multiboot_mod_list) * NUM_MODULES); error = bi_load64(fp->f_args, &modulep, &kernend, 0); if (error != 0) { printf("bi_load64 failed: %d\n", error); goto error; } mb_mod[0].mod_start = fp->f_addr; mb_mod[0].mod_end = fp->f_addr + fp->f_size - PAGE_SIZE; mb_mod[1].mod_start = mb_mod[0].mod_end; mb_mod[1].mod_end = kernend; /* Indicate the kernel metadata is prefixed with a xen_header. */ cmdline = strdup("header"); if (cmdline == NULL) { printf("Out of memory, aborting\n"); error = ENOMEM; goto error; } mb_mod[1].cmdline = VTOP(cmdline); mb_info->mods_count = NUM_MODULES; mb_info->mods_addr = VTOP(mb_mod); mb_info->flags |= MULTIBOOT_INFO_MODS; header.flags = XENHEADER_HAS_MODULEP_OFFSET; header.modulep_offset = modulep - mb_mod[1].mod_start; archsw.arch_copyin(&header, mb_mod[1].mod_start, sizeof(header)); dev_cleanup(); __exec((void *)VTOP(multiboot_tramp), (void *)entry, (void *)VTOP(mb_info)); panic("exec returned"); error: if (mb_mod) free(mb_mod); if (mb_info) free(mb_info); if (cmdline) free(cmdline); return (error); } static int multiboot_obj_loadfile(char *filename, uint64_t dest, struct preloaded_file **result) { struct preloaded_file *mfp, *kfp, *rfp; struct kernel_module *kmp; int error, mod_num; /* See if there's a multiboot kernel loaded */ mfp = file_findfile(NULL, "elf multiboot kernel"); if (mfp == NULL) return (EFTYPE); /* * We have a multiboot kernel loaded, see if there's a FreeBSD * kernel loaded also. */ kfp = file_findfile(NULL, "elf kernel"); if (kfp == NULL) { /* * No kernel loaded, this must be it. The kernel has to * be loaded as a raw file, it will be processed by * Xen and correctly loaded as an ELF file. */ rfp = file_loadraw(filename, "elf kernel", 0); if (rfp == NULL) { printf( "Unable to load %s as a multiboot payload kernel\n", filename); return (EINVAL); } /* Load kernel metadata... */ setenv("kernelname", filename, 1); error = elf64_load_modmetadata(rfp, rfp->f_addr + rfp->f_size); if (error) { printf("Unable to load kernel %s metadata error: %d\n", rfp->f_name, error); return (EINVAL); } /* * Reserve one page at the end of the kernel to place some * metadata in order to cope for Xen relocating the modules and * the metadata information. */ rfp->f_size = roundup(rfp->f_size, PAGE_SIZE); rfp->f_size += PAGE_SIZE; *result = rfp; } else { /* The rest should be loaded as regular modules */ error = elf64_obj_loadfile(filename, dest, result); if (error != 0) { printf("Unable to load %s as an object file, error: %d", filename, error); return (error); } } return (0); } static int multiboot_obj_exec(struct preloaded_file *fp) { return (EFTYPE); }