freebsd-dev/sys/boot/common/bootstrap.h
Roger Pau Monné ca49b3342d loader: implement multiboot support for Xen Dom0
Implement a subset of the multiboot specification in order to boot Xen
and a FreeBSD Dom0 from the FreeBSD bootloader. This multiboot
implementation is tailored to boot Xen and FreeBSD Dom0, and it will
most surely fail to boot any other multiboot compilant kernel.

In order to detect and boot the Xen microkernel, two new file formats
are added to the bootloader, multiboot and multiboot_obj. Multiboot
support must be tested before regular ELF support, since Xen is a
multiboot kernel that also uses ELF. After a multiboot kernel is
detected, all the other loaded kernels/modules are parsed by the
multiboot_obj format.

The layout of the loaded objects in memory is the following; first the
Xen kernel is loaded as a 32bit ELF into memory (Xen will switch to
long mode by itself), after that the FreeBSD kernel is loaded as a RAW
file (Xen will parse and load it using it's internal ELF loader), and
finally the metadata and the modules are loaded using the native
FreeBSD way. After everything is loaded we jump into Xen's entry point
using a small trampoline. The order of the multiboot modules passed to
Xen is the following, the first module is the RAW FreeBSD kernel, and
the second module is the metadata and the FreeBSD modules.

Since Xen will relocate the memory position of the second
multiboot module (the one that contains the metadata and native
FreeBSD modules), we need to stash the original modulep address inside
of the metadata itself in order to recalculate its position once
booted. This also means the metadata must come before the loaded
modules, so after loading the FreeBSD kernel a portion of memory is
reserved in order to place the metadata before booting.

In order to tell the loader to boot Xen and then the FreeBSD kernel the
following has to be added to the /boot/loader.conf file:

xen_cmdline="dom0_mem=1024M dom0_max_vcpus=2 dom0pvh=1 console=com1,vga"
xen_kernel="/boot/xen"

The first argument contains the command line that will be passed to the Xen
kernel, while the second argument is the path to the Xen kernel itself. This
can also be done manually from the loader command line, by for example
typing the following set of commands:

OK unload
OK load /boot/xen dom0_mem=1024M dom0_max_vcpus=2 dom0pvh=1 console=com1,vga
OK load kernel
OK load zfs
OK load if_tap
OK load ...
OK boot

Sponsored by: Citrix Systems R&D
Reviewed by: jhb
Differential Revision: https://reviews.freebsd.org/D517

For the Forth bits:
Submitted by: Julien Grall <julien.grall AT citrix.com>
2015-01-15 16:27:20 +00:00

345 lines
11 KiB
C

/*-
* Copyright (c) 1998 Michael Smith <msmith@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.
*
* $FreeBSD$
*/
#ifndef _BOOTSTRAP_H_
#define _BOOTSTRAP_H_
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/linker_set.h>
/*
* Generic device specifier; architecture-dependant
* versions may be larger, but should be allowed to
* overlap.
*/
struct devdesc
{
struct devsw *d_dev;
int d_type;
#define DEVT_NONE 0
#define DEVT_DISK 1
#define DEVT_NET 2
#define DEVT_CD 3
#define DEVT_ZFS 4
int d_unit;
void *d_opendata;
};
/* Commands and return values; nonzero return sets command_errmsg != NULL */
typedef int (bootblk_cmd_t)(int argc, char *argv[]);
extern char *command_errmsg;
extern char command_errbuf[]; /* XXX blah, length */
#define CMD_OK 0
#define CMD_ERROR 1
/* interp.c */
void interact(const char *rc);
int include(const char *filename);
/* interp_backslash.c */
char *backslash(char *str);
/* interp_parse.c */
int parse(int *argc, char ***argv, char *str);
/* interp_forth.c */
void bf_init(const char *rc);
int bf_run(char *line);
/* boot.c */
int autoboot(int timeout, char *prompt);
void autoboot_maybe(void);
int getrootmount(char *rootdev);
/* misc.c */
char *unargv(int argc, char *argv[]);
void hexdump(caddr_t region, size_t len);
size_t strlenout(vm_offset_t str);
char *strdupout(vm_offset_t str);
void kern_bzero(vm_offset_t dest, size_t len);
int kern_pread(int fd, vm_offset_t dest, size_t len, off_t off);
void *alloc_pread(int fd, off_t off, size_t len);
/* bcache.c */
int bcache_init(u_int nblks, size_t bsize);
void bcache_flush(void);
int bcache_strategy(void *devdata, int unit, int rw, daddr_t blk,
size_t size, char *buf, size_t *rsize);
/*
* Disk block cache
*/
struct bcache_devdata
{
int (*dv_strategy)(void *devdata, int rw, daddr_t blk, size_t size, char *buf, size_t *rsize);
void *dv_devdata;
};
/*
* Modular console support.
*/
struct console
{
const char *c_name;
const char *c_desc;
int c_flags;
#define C_PRESENTIN (1<<0) /* console can provide input */
#define C_PRESENTOUT (1<<1) /* console can provide output */
#define C_ACTIVEIN (1<<2) /* user wants input from console */
#define C_ACTIVEOUT (1<<3) /* user wants output to console */
void (* c_probe)(struct console *cp); /* set c_flags to match hardware */
int (* c_init)(int arg); /* reinit XXX may need more args */
void (* c_out)(int c); /* emit c */
int (* c_in)(void); /* wait for and return input */
int (* c_ready)(void); /* return nonzer if input waiting */
};
extern struct console *consoles[];
void cons_probe(void);
/*
* Plug-and-play enumerator/configurator interface.
*/
struct pnphandler
{
const char *pp_name; /* handler/bus name */
void (* pp_enumerate)(void); /* enumerate PnP devices, add to chain */
};
struct pnpident
{
char *id_ident; /* ASCII identifier, actual format varies with bus/handler */
STAILQ_ENTRY(pnpident) id_link;
};
struct pnpinfo
{
char *pi_desc; /* ASCII description, optional */
int pi_revision; /* optional revision (or -1) if not supported */
char *pi_module; /* module/args nominated to handle device */
int pi_argc; /* module arguments */
char **pi_argv;
struct pnphandler *pi_handler; /* handler which detected this device */
STAILQ_HEAD(,pnpident) pi_ident; /* list of identifiers */
STAILQ_ENTRY(pnpinfo) pi_link;
};
STAILQ_HEAD(pnpinfo_stql, pnpinfo);
extern struct pnpinfo_stql pnp_devices;
extern struct pnphandler *pnphandlers[]; /* provided by MD code */
void pnp_addident(struct pnpinfo *pi, char *ident);
struct pnpinfo *pnp_allocinfo(void);
void pnp_freeinfo(struct pnpinfo *pi);
void pnp_addinfo(struct pnpinfo *pi);
char *pnp_eisaformat(u_int8_t *data);
/*
* < 0 - No ISA in system
* == 0 - Maybe ISA, search for read data port
* > 0 - ISA in system, value is read data port address
*/
extern int isapnp_readport;
/*
* Preloaded file metadata header.
*
* Metadata are allocated on our heap, and copied into kernel space
* before executing the kernel.
*/
struct file_metadata
{
size_t md_size;
u_int16_t md_type;
struct file_metadata *md_next;
char md_data[1]; /* data are immediately appended */
};
struct preloaded_file;
struct mod_depend;
struct kernel_module
{
char *m_name; /* module name */
int m_version; /* module version */
/* char *m_args;*/ /* arguments for the module */
struct preloaded_file *m_fp;
struct kernel_module *m_next;
};
/*
* Preloaded file information. Depending on type, file can contain
* additional units called 'modules'.
*
* At least one file (the kernel) must be loaded in order to boot.
* The kernel is always loaded first.
*
* String fields (m_name, m_type) should be dynamically allocated.
*/
struct preloaded_file
{
char *f_name; /* file name */
char *f_type; /* verbose file type, eg 'ELF kernel', 'pnptable', etc. */
char *f_args; /* arguments for the file */
struct file_metadata *f_metadata; /* metadata that will be placed in the module directory */
int f_loader; /* index of the loader that read the file */
vm_offset_t f_addr; /* load address */
size_t f_size; /* file size */
struct kernel_module *f_modules; /* list of modules if any */
struct preloaded_file *f_next; /* next file */
};
struct file_format
{
/* Load function must return EFTYPE if it can't handle the module supplied */
int (* l_load)(char *filename, u_int64_t dest, struct preloaded_file **result);
/* Only a loader that will load a kernel (first module) should have an exec handler */
int (* l_exec)(struct preloaded_file *mp);
};
extern struct file_format *file_formats[]; /* supplied by consumer */
extern struct preloaded_file *preloaded_files;
int mod_load(char *name, struct mod_depend *verinfo, int argc, char *argv[]);
int mod_loadkld(const char *name, int argc, char *argv[]);
void unload(void);
struct preloaded_file *file_alloc(void);
struct preloaded_file *file_findfile(const char *name, const char *type);
struct file_metadata *file_findmetadata(struct preloaded_file *fp, int type);
struct preloaded_file *file_loadraw(char *name, char *type, int insert);
void file_discard(struct preloaded_file *fp);
void file_addmetadata(struct preloaded_file *fp, int type, size_t size, void *p);
int file_addmodule(struct preloaded_file *fp, char *modname, int version,
struct kernel_module **newmp);
/* MI module loaders */
#ifdef __elfN
/* Relocation types. */
#define ELF_RELOC_REL 1
#define ELF_RELOC_RELA 2
/* Relocation offset for some architectures */
extern u_int64_t __elfN(relocation_offset);
struct elf_file;
typedef Elf_Addr (symaddr_fn)(struct elf_file *ef, Elf_Size symidx);
int __elfN(loadfile)(char *filename, u_int64_t dest, struct preloaded_file **result);
int __elfN(obj_loadfile)(char *filename, u_int64_t dest,
struct preloaded_file **result);
int __elfN(reloc)(struct elf_file *ef, symaddr_fn *symaddr,
const void *reldata, int reltype, Elf_Addr relbase,
Elf_Addr dataaddr, void *data, size_t len);
int __elfN(loadfile_raw)(char *filename, u_int64_t dest,
struct preloaded_file **result, int multiboot);
int __elfN(load_modmetadata)(struct preloaded_file *fp, u_int64_t dest);
#endif
/*
* Support for commands
*/
struct bootblk_command
{
const char *c_name;
const char *c_desc;
bootblk_cmd_t *c_fn;
};
#define COMMAND_SET(tag, key, desc, func) \
static bootblk_cmd_t func; \
static struct bootblk_command _cmd_ ## tag = { key, desc, func }; \
DATA_SET(Xcommand_set, _cmd_ ## tag)
SET_DECLARE(Xcommand_set, struct bootblk_command);
/*
* The intention of the architecture switch is to provide a convenient
* encapsulation of the interface between the bootstrap MI and MD code.
* MD code may selectively populate the switch at runtime based on the
* actual configuration of the target system.
*/
struct arch_switch
{
/* Automatically load modules as required by detected hardware */
int (*arch_autoload)(void);
/* Locate the device for (name), return pointer to tail in (*path) */
int (*arch_getdev)(void **dev, const char *name, const char **path);
/* Copy from local address space to module address space, similar to bcopy() */
ssize_t (*arch_copyin)(const void *src, vm_offset_t dest,
const size_t len);
/* Copy to local address space from module address space, similar to bcopy() */
ssize_t (*arch_copyout)(const vm_offset_t src, void *dest,
const size_t len);
/* Read from file to module address space, same semantics as read() */
ssize_t (*arch_readin)(const int fd, vm_offset_t dest,
const size_t len);
/* Perform ISA byte port I/O (only for systems with ISA) */
int (*arch_isainb)(int port);
void (*arch_isaoutb)(int port, int value);
/*
* Interface to adjust the load address according to the "object"
* being loaded.
*/
uint64_t (*arch_loadaddr)(u_int type, void *data, uint64_t addr);
#define LOAD_ELF 1 /* data points to the ELF header. */
#define LOAD_RAW 2 /* data points to the file name. */
/*
* Interface to inform MD code about a loaded (ELF) segment. This
* can be used to flush caches and/or set up translations.
*/
#ifdef __elfN
void (*arch_loadseg)(Elf_Ehdr *eh, Elf_Phdr *ph, uint64_t delta);
#else
void (*arch_loadseg)(void *eh, void *ph, uint64_t delta);
#endif
/* Probe ZFS pool(s), if needed. */
void (*arch_zfs_probe)(void);
};
extern struct arch_switch archsw;
/* This must be provided by the MD code, but should it be in the archsw? */
void delay(int delay);
void dev_cleanup(void);
time_t time(time_t *tloc);
#ifndef CTASSERT /* Allow lint to override */
#define CTASSERT(x) _CTASSERT(x, __LINE__)
#define _CTASSERT(x, y) __CTASSERT(x, y)
#define __CTASSERT(x, y) typedef char __assert ## y[(x) ? 1 : -1]
#endif
#endif /* !_BOOTSTRAP_H_ */