kernel_optimize_test/arch/um/kernel/um_arch.c
Paolo 'Blaisorblade' Giarrusso 0221575903 [PATCH] uml: workaround GDB problems on debugging
Apparently, GDB gets confused when we do an execvp() on ourselves.

Since it's simply done to allocate further space for command line arguments
(which we'll use to allow gathering the startup command line for guest
processes through the host), allow the user to disable that to get a
debuggable UML binary.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-05 00:06:20 -07:00

481 lines
11 KiB
C

/*
* Copyright (C) 2000, 2002 Jeff Dike (jdike@karaya.com)
* Licensed under the GPL
*/
#include "linux/config.h"
#include "linux/kernel.h"
#include "linux/sched.h"
#include "linux/notifier.h"
#include "linux/mm.h"
#include "linux/types.h"
#include "linux/tty.h"
#include "linux/init.h"
#include "linux/bootmem.h"
#include "linux/spinlock.h"
#include "linux/utsname.h"
#include "linux/sysrq.h"
#include "linux/seq_file.h"
#include "linux/delay.h"
#include "linux/module.h"
#include "asm/page.h"
#include "asm/pgtable.h"
#include "asm/ptrace.h"
#include "asm/elf.h"
#include "asm/user.h"
#include "asm/setup.h"
#include "ubd_user.h"
#include "asm/current.h"
#include "user_util.h"
#include "kern_util.h"
#include "kern.h"
#include "mem_user.h"
#include "mem.h"
#include "umid.h"
#include "initrd.h"
#include "init.h"
#include "os.h"
#include "choose-mode.h"
#include "mode_kern.h"
#include "mode.h"
#ifdef UML_CONFIG_MODE_SKAS
#include "skas.h"
#endif
#define DEFAULT_COMMAND_LINE "root=98:0"
/* Changed in linux_main and setup_arch, which run before SMP is started */
static char command_line[COMMAND_LINE_SIZE] = { 0 };
static void add_arg(char *arg)
{
if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
printf("add_arg: Too many command line arguments!\n");
exit(1);
}
if(strlen(command_line) > 0)
strcat(command_line, " ");
strcat(command_line, arg);
}
struct cpuinfo_um boot_cpu_data = {
.loops_per_jiffy = 0,
.ipi_pipe = { -1, -1 }
};
unsigned long thread_saved_pc(struct task_struct *task)
{
return(os_process_pc(CHOOSE_MODE_PROC(thread_pid_tt, thread_pid_skas,
task)));
}
static int show_cpuinfo(struct seq_file *m, void *v)
{
int index = 0;
#ifdef CONFIG_SMP
index = (struct cpuinfo_um *) v - cpu_data;
if (!cpu_online(index))
return 0;
#endif
seq_printf(m, "processor\t: %d\n", index);
seq_printf(m, "vendor_id\t: User Mode Linux\n");
seq_printf(m, "model name\t: UML\n");
seq_printf(m, "mode\t\t: %s\n", CHOOSE_MODE("tt", "skas"));
seq_printf(m, "host\t\t: %s\n", host_info);
seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
loops_per_jiffy/(500000/HZ),
(loops_per_jiffy/(5000/HZ)) % 100);
return(0);
}
static void *c_start(struct seq_file *m, loff_t *pos)
{
return *pos < NR_CPUS ? cpu_data + *pos : NULL;
}
static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
++*pos;
return c_start(m, pos);
}
static void c_stop(struct seq_file *m, void *v)
{
}
struct seq_operations cpuinfo_op = {
.start = c_start,
.next = c_next,
.stop = c_stop,
.show = show_cpuinfo,
};
/* Set in linux_main */
unsigned long host_task_size;
unsigned long task_size;
unsigned long uml_start;
/* Set in early boot */
unsigned long uml_physmem;
unsigned long uml_reserved;
unsigned long start_vm;
unsigned long end_vm;
int ncpus = 1;
#ifdef CONFIG_CMDLINE_ON_HOST
/* Pointer set in linux_main, the array itself is private to each thread,
* and changed at address space creation time so this poses no concurrency
* problems.
*/
static char *argv1_begin = NULL;
static char *argv1_end = NULL;
#endif
/* Set in early boot */
static int have_root __initdata = 0;
long physmem_size = 32 * 1024 * 1024;
void set_cmdline(char *cmd)
{
#ifdef CONFIG_CMDLINE_ON_HOST
char *umid, *ptr;
if(CHOOSE_MODE(honeypot, 0)) return;
umid = get_umid(1);
if(umid != NULL){
snprintf(argv1_begin,
(argv1_end - argv1_begin) * sizeof(*ptr),
"(%s) ", umid);
ptr = &argv1_begin[strlen(argv1_begin)];
}
else ptr = argv1_begin;
snprintf(ptr, (argv1_end - ptr) * sizeof(*ptr), "[%s]", cmd);
memset(argv1_begin + strlen(argv1_begin), '\0',
argv1_end - argv1_begin - strlen(argv1_begin));
#endif
}
static char *usage_string =
"User Mode Linux v%s\n"
" available at http://user-mode-linux.sourceforge.net/\n\n";
static int __init uml_version_setup(char *line, int *add)
{
printf("%s\n", system_utsname.release);
exit(0);
return 0;
}
__uml_setup("--version", uml_version_setup,
"--version\n"
" Prints the version number of the kernel.\n\n"
);
static int __init uml_root_setup(char *line, int *add)
{
have_root = 1;
return 0;
}
__uml_setup("root=", uml_root_setup,
"root=<file containing the root fs>\n"
" This is actually used by the generic kernel in exactly the same\n"
" way as in any other kernel. If you configure a number of block\n"
" devices and want to boot off something other than ubd0, you \n"
" would use something like:\n"
" root=/dev/ubd5\n\n"
);
#ifdef CONFIG_SMP
static int __init uml_ncpus_setup(char *line, int *add)
{
if (!sscanf(line, "%d", &ncpus)) {
printf("Couldn't parse [%s]\n", line);
return -1;
}
return 0;
}
__uml_setup("ncpus=", uml_ncpus_setup,
"ncpus=<# of desired CPUs>\n"
" This tells an SMP kernel how many virtual processors to start.\n\n"
);
#endif
static int force_tt = 0;
#if defined(CONFIG_MODE_TT) && defined(CONFIG_MODE_SKAS)
#define DEFAULT_TT 0
static int __init mode_tt_setup(char *line, int *add)
{
force_tt = 1;
return(0);
}
#else
#ifdef CONFIG_MODE_SKAS
#define DEFAULT_TT 0
static int __init mode_tt_setup(char *line, int *add)
{
printf("CONFIG_MODE_TT disabled - 'mode=tt' ignored\n");
return(0);
}
#else
#ifdef CONFIG_MODE_TT
#define DEFAULT_TT 1
static int __init mode_tt_setup(char *line, int *add)
{
printf("CONFIG_MODE_SKAS disabled - 'mode=tt' redundant\n");
return(0);
}
#else
#error Either CONFIG_MODE_TT or CONFIG_MODE_SKAS must be enabled
#endif
#endif
#endif
__uml_setup("mode=tt", mode_tt_setup,
"mode=tt\n"
" When both CONFIG_MODE_TT and CONFIG_MODE_SKAS are enabled, this option\n"
" forces UML to run in tt (tracing thread) mode. It is not the default\n"
" because it's slower and less secure than skas mode.\n\n"
);
int mode_tt = DEFAULT_TT;
static int __init Usage(char *line, int *add)
{
const char **p;
printf(usage_string, system_utsname.release);
p = &__uml_help_start;
while (p < &__uml_help_end) {
printf("%s", *p);
p++;
}
exit(0);
return 0;
}
__uml_setup("--help", Usage,
"--help\n"
" Prints this message.\n\n"
);
static int __init uml_checksetup(char *line, int *add)
{
struct uml_param *p;
p = &__uml_setup_start;
while(p < &__uml_setup_end) {
int n;
n = strlen(p->str);
if(!strncmp(line, p->str, n)){
if (p->setup_func(line + n, add)) return 1;
}
p++;
}
return 0;
}
static void __init uml_postsetup(void)
{
initcall_t *p;
p = &__uml_postsetup_start;
while(p < &__uml_postsetup_end){
(*p)();
p++;
}
return;
}
/* Set during early boot */
unsigned long brk_start;
unsigned long end_iomem;
EXPORT_SYMBOL(end_iomem);
#define MIN_VMALLOC (32 * 1024 * 1024)
int linux_main(int argc, char **argv)
{
unsigned long avail, diff;
unsigned long virtmem_size, max_physmem;
unsigned int i, add;
char * mode;
for (i = 1; i < argc; i++){
if((i == 1) && (argv[i][0] == ' ')) continue;
add = 1;
uml_checksetup(argv[i], &add);
if (add)
add_arg(argv[i]);
}
if(have_root == 0)
add_arg(DEFAULT_COMMAND_LINE);
mode_tt = force_tt ? 1 : !can_do_skas();
#ifndef CONFIG_MODE_TT
if (mode_tt) {
/*Since CONFIG_MODE_TT is #undef'ed, force_tt cannot be 1. So,
* can_do_skas() returned 0, and the message is correct. */
printf("Support for TT mode is disabled, and no SKAS support is present on the host.\n");
exit(1);
}
#endif
#ifndef CONFIG_MODE_SKAS
mode = "TT";
#else
/* Show to the user the result of selection */
if (mode_tt)
mode = "TT";
else if (proc_mm && ptrace_faultinfo)
mode = "SKAS3";
else
mode = "SKAS0";
#endif
printf("UML running in %s mode\n", mode);
uml_start = CHOOSE_MODE_PROC(set_task_sizes_tt, set_task_sizes_skas, 0,
&host_task_size, &task_size);
/* Need to check this early because mmapping happens before the
* kernel is running.
*/
check_tmpexec();
brk_start = (unsigned long) sbrk(0);
CHOOSE_MODE_PROC(before_mem_tt, before_mem_skas, brk_start);
/* Increase physical memory size for exec-shield users
so they actually get what they asked for. This should
add zero for non-exec shield users */
diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
if(diff > 1024 * 1024){
printf("Adding %ld bytes to physical memory to account for "
"exec-shield gap\n", diff);
physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
}
uml_physmem = uml_start;
/* Reserve up to 4M after the current brk */
uml_reserved = ROUND_4M(brk_start) + (1 << 22);
setup_machinename(system_utsname.machine);
#ifdef CONFIG_CMDLINE_ON_HOST
argv1_begin = argv[1];
argv1_end = &argv[1][strlen(argv[1])];
#endif
highmem = 0;
iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
max_physmem = get_kmem_end() - uml_physmem - iomem_size - MIN_VMALLOC;
/* Zones have to begin on a 1 << MAX_ORDER page boundary,
* so this makes sure that's true for highmem
*/
max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
if(physmem_size + iomem_size > max_physmem){
highmem = physmem_size + iomem_size - max_physmem;
physmem_size -= highmem;
#ifndef CONFIG_HIGHMEM
highmem = 0;
printf("CONFIG_HIGHMEM not enabled - physical memory shrunk "
"to %ld bytes\n", physmem_size);
#endif
}
high_physmem = uml_physmem + physmem_size;
end_iomem = high_physmem + iomem_size;
high_memory = (void *) end_iomem;
start_vm = VMALLOC_START;
setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
if(init_maps(physmem_size, iomem_size, highmem)){
printf("Failed to allocate mem_map for %ld bytes of physical "
"memory and %ld bytes of highmem\n", physmem_size,
highmem);
exit(1);
}
virtmem_size = physmem_size;
avail = get_kmem_end() - start_vm;
if(physmem_size > avail) virtmem_size = avail;
end_vm = start_vm + virtmem_size;
if(virtmem_size < physmem_size)
printf("Kernel virtual memory size shrunk to %ld bytes\n",
virtmem_size);
uml_postsetup();
task_protections((unsigned long) &init_thread_info);
os_flush_stdout();
return(CHOOSE_MODE(start_uml_tt(), start_uml_skas()));
}
extern int uml_exitcode;
static int panic_exit(struct notifier_block *self, unsigned long unused1,
void *unused2)
{
bust_spinlocks(1);
show_regs(&(current->thread.regs));
bust_spinlocks(0);
uml_exitcode = 1;
machine_halt();
return(0);
}
static struct notifier_block panic_exit_notifier = {
.notifier_call = panic_exit,
.next = NULL,
.priority = 0
};
void __init setup_arch(char **cmdline_p)
{
notifier_chain_register(&panic_notifier_list, &panic_exit_notifier);
paging_init();
strlcpy(saved_command_line, command_line, COMMAND_LINE_SIZE);
*cmdline_p = command_line;
setup_hostinfo();
}
void __init check_bugs(void)
{
arch_check_bugs();
check_ptrace();
check_sigio();
check_devanon();
}
void apply_alternatives(void *start, void *end)
{
}