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Diffstat (limited to 'stand/i386/libi386/multiboot.c')
-rw-r--r--stand/i386/libi386/multiboot.c467
1 files changed, 467 insertions, 0 deletions
diff --git a/stand/i386/libi386/multiboot.c b/stand/i386/libi386/multiboot.c
new file mode 100644
index 000000000000..9aac64010a1f
--- /dev/null
+++ b/stand/i386/libi386/multiboot.c
@@ -0,0 +1,467 @@
+/*-
+ * Copyright (c) 2014 Roger Pau Monné <royger@FreeBSD.org>
+ * 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 <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/exec.h>
+#include <sys/linker.h>
+#include <sys/module.h>
+#include <sys/stdint.h>
+#define _MACHINE_ELF_WANT_32BIT
+#include <machine/elf.h>
+#include <string.h>
+#include <stand.h>
+
+#include "bootstrap.h"
+#include "multiboot.h"
+#include "../i386/libi386/libi386.h"
+#include "../i386/btx/lib/btxv86.h"
+
+#define MULTIBOOT_SUPPORTED_FLAGS \
+ (MULTIBOOT_PAGE_ALIGN|MULTIBOOT_MEMORY_INFO)
+#define NUM_MODULES 2
+#define METADATA_FIXED_SIZE (PAGE_SIZE*4)
+#define METADATA_MODULE_SIZE PAGE_SIZE
+
+#define METADATA_RESV_SIZE(mod_num) \
+ roundup(METADATA_FIXED_SIZE + METADATA_MODULE_SIZE * mod_num, PAGE_SIZE)
+
+extern int elf32_loadfile_raw(char *filename, u_int64_t dest,
+ struct preloaded_file **result, int multiboot);
+extern int elf64_load_modmetadata(struct preloaded_file *fp, u_int64_t dest);
+extern int elf64_obj_loadfile(char *filename, u_int64_t dest,
+ struct preloaded_file **result);
+
+static int multiboot_loadfile(char *, u_int64_t, struct preloaded_file **);
+static int multiboot_exec(struct preloaded_file *);
+
+static int multiboot_obj_loadfile(char *, u_int64_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
+num_modules(struct preloaded_file *kfp)
+{
+ struct kernel_module *kmp;
+ int mod_num = 0;
+
+ for (kmp = kfp->f_modules; kmp != NULL; kmp = kmp->m_next)
+ mod_num++;
+
+ return (mod_num);
+}
+
+static vm_offset_t
+max_addr(void)
+{
+ struct preloaded_file *fp;
+ vm_offset_t addr = 0;
+
+ for (fp = file_findfile(NULL, NULL); fp != NULL; fp = fp->f_next) {
+ if (addr < (fp->f_addr + fp->f_size))
+ addr = fp->f_addr + fp->f_size;
+ }
+
+ return (addr);
+}
+
+static int
+multiboot_loadfile(char *filename, u_int64_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 module_start, last_addr, metadata_size;
+ 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;
+
+ /*
+ * 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.
+ *
+ * On native FreeBSD loads all the modules and then places the
+ * metadata info at the end, but this is painful when running on Xen,
+ * because it relocates the second multiboot module wherever it
+ * likes. In order to workaround this limitation the metadata
+ * information is placed at the start of the second module and
+ * the original modulep value is saved together with the other
+ * metadata, so we can relocate everything.
+ *
+ * Native layout:
+ * fp->f_addr + fp->f_size
+ * +---------+----------------+------------+
+ * | | | |
+ * | Kernel | Modules | Metadata |
+ * | | | |
+ * +---------+----------------+------------+
+ * fp->f_addr modulep kernend
+ *
+ * Xen layout:
+ *
+ * Initial:
+ * fp->f_addr + fp->f_size
+ * +---------+----------+----------------+------------+
+ * | | | | |
+ * | Kernel | Reserved | Modules | Metadata |
+ * | | | | dry run |
+ * +---------+----------+----------------+------------+
+ * fp->f_addr
+ *
+ * After metadata polacement (ie: final):
+ * fp->f_addr + fp->f_size
+ * +-----------+---------+----------+----------------+
+ * | | | | |
+ * | Kernel | Free | Metadata | Modules |
+ * | | | | |
+ * +-----------+---------+----------+----------------+
+ * fp->f_addr modulep kernend
+ * \__________/ \__________________________/
+ * Multiboot module 0 Multiboot module 1
+ */
+
+ fp = file_findfile(NULL, "elf kernel");
+ if (fp == NULL) {
+ printf("No FreeBSD kernel provided, aborting\n");
+ error = EINVAL;
+ goto error;
+ }
+
+ if (fp->f_metadata != NULL) {
+ printf("FreeBSD kernel already contains metadata, 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);
+
+ /*
+ * Calculate how much memory is needed for the metatdata. We did
+ * an approximation of the maximum size when loading the kernel,
+ * but now we know the exact size, so we can release some of this
+ * preallocated memory if not needed.
+ */
+ last_addr = roundup(max_addr(), PAGE_SIZE);
+ mod_num = num_modules(fp);
+
+ /*
+ * Place the metadata after the last used address in order to
+ * calculate it's size, this will not be used.
+ */
+ error = bi_load64(fp->f_args, last_addr, &modulep, &kernend, 0);
+ if (error != 0) {
+ printf("bi_load64 failed: %d\n", error);
+ goto error;
+ }
+ metadata_size = roundup(kernend - last_addr, PAGE_SIZE);
+
+ /* Check that the size is not greater than what we have reserved */
+ if (metadata_size > METADATA_RESV_SIZE(mod_num)) {
+ printf("Required memory for metadata is greater than reserved "
+ "space, please increase METADATA_FIXED_SIZE and "
+ "METADATA_MODULE_SIZE and rebuild the loader\n");
+ error = ENOMEM;
+ goto error;
+ }
+
+ /* Clean the metadata added to the kernel in the bi_load64 dry run */
+ file_removemetadata(fp);
+
+ /*
+ * This is the position where the second multiboot module
+ * will be placed.
+ */
+ module_start = fp->f_addr + fp->f_size - metadata_size;
+
+ error = bi_load64(fp->f_args, module_start, &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;
+ mb_mod[0].mod_end -= METADATA_RESV_SIZE(mod_num);
+
+ mb_mod[1].mod_start = module_start;
+ mb_mod[1].mod_end = last_addr;
+
+ mb_info->mods_count = NUM_MODULES;
+ mb_info->mods_addr = VTOP(mb_mod);
+ mb_info->flags |= MULTIBOOT_INFO_MODS;
+
+ 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, u_int64_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);
+ }
+
+ /*
+ * Save space at the end of the kernel in order to place
+ * the metadata information. We do an approximation of the
+ * max metadata size, this is not optimal but it's probably
+ * the best we can do at this point. Once all modules are
+ * loaded and the size of the metadata is known this
+ * space will be recovered if not used.
+ */
+ mod_num = num_modules(rfp);
+ rfp->f_size = roundup(rfp->f_size, PAGE_SIZE);
+ rfp->f_size += METADATA_RESV_SIZE(mod_num);
+ *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);
+}
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