linux/arch/um/kernel/process_kern.c
Paolo 'Blaisorblade' Giarrusso aa6758d486 [PATCH] uml: implement {get,set}_thread_area for i386
Implement sys_[gs]et_thread_area and the corresponding ptrace operations for
UML.  This is the main chunk, additional parts follow.  This implementation is
now well tested and has run reliably for some time, and we've understood all
the previously existing problems.

Their implementation saves the new GDT content and then forwards the call to
the host when appropriate, i.e.  immediately when the target process is
running or on context switch otherwise (i.e.  on fork and on ptrace() calls).

In SKAS mode, we must switch registers on each context switch (because SKAS
does not switches tls_array together with current->mm).

Also, added get_cpu() locking; this has been done for SKAS mode, since TT does
not need it (it does not use smp_processor_id()).

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-31 12:18:52 -08:00

484 lines
9.3 KiB
C

/*
* Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
* Copyright 2003 PathScale, Inc.
* Licensed under the GPL
*/
#include "linux/config.h"
#include "linux/kernel.h"
#include "linux/sched.h"
#include "linux/interrupt.h"
#include "linux/string.h"
#include "linux/mm.h"
#include "linux/slab.h"
#include "linux/utsname.h"
#include "linux/fs.h"
#include "linux/utime.h"
#include "linux/smp_lock.h"
#include "linux/module.h"
#include "linux/init.h"
#include "linux/capability.h"
#include "linux/vmalloc.h"
#include "linux/spinlock.h"
#include "linux/proc_fs.h"
#include "linux/ptrace.h"
#include "linux/random.h"
#include "asm/unistd.h"
#include "asm/mman.h"
#include "asm/segment.h"
#include "asm/stat.h"
#include "asm/pgtable.h"
#include "asm/processor.h"
#include "asm/tlbflush.h"
#include "asm/uaccess.h"
#include "asm/user.h"
#include "user_util.h"
#include "kern_util.h"
#include "kern.h"
#include "signal_kern.h"
#include "init.h"
#include "irq_user.h"
#include "mem_user.h"
#include "tlb.h"
#include "frame_kern.h"
#include "sigcontext.h"
#include "os.h"
#include "mode.h"
#include "mode_kern.h"
#include "choose-mode.h"
/* This is a per-cpu array. A processor only modifies its entry and it only
* cares about its entry, so it's OK if another processor is modifying its
* entry.
*/
struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
int external_pid(void *t)
{
struct task_struct *task = t ? t : current;
return(CHOOSE_MODE_PROC(external_pid_tt, external_pid_skas, task));
}
int pid_to_processor_id(int pid)
{
int i;
for(i = 0; i < ncpus; i++){
if(cpu_tasks[i].pid == pid) return(i);
}
return(-1);
}
void free_stack(unsigned long stack, int order)
{
free_pages(stack, order);
}
unsigned long alloc_stack(int order, int atomic)
{
unsigned long page;
gfp_t flags = GFP_KERNEL;
if (atomic)
flags = GFP_ATOMIC;
page = __get_free_pages(flags, order);
if(page == 0)
return(0);
stack_protections(page);
return(page);
}
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
int pid;
current->thread.request.u.thread.proc = fn;
current->thread.request.u.thread.arg = arg;
pid = do_fork(CLONE_VM | CLONE_UNTRACED | flags, 0,
&current->thread.regs, 0, NULL, NULL);
if(pid < 0)
panic("do_fork failed in kernel_thread, errno = %d", pid);
return(pid);
}
void set_current(void *t)
{
struct task_struct *task = t;
cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
{ external_pid(task), task });
}
void *_switch_to(void *prev, void *next, void *last)
{
struct task_struct *from = prev;
struct task_struct *to= next;
to->thread.prev_sched = from;
set_current(to);
do {
current->thread.saved_task = NULL ;
CHOOSE_MODE_PROC(switch_to_tt, switch_to_skas, prev, next);
if(current->thread.saved_task)
show_regs(&(current->thread.regs));
next= current->thread.saved_task;
prev= current;
} while(current->thread.saved_task);
return(current->thread.prev_sched);
}
void interrupt_end(void)
{
if(need_resched()) schedule();
if(test_tsk_thread_flag(current, TIF_SIGPENDING)) do_signal();
}
void release_thread(struct task_struct *task)
{
CHOOSE_MODE(release_thread_tt(task), release_thread_skas(task));
}
void exit_thread(void)
{
unprotect_stack((unsigned long) current_thread);
}
void *get_current(void)
{
return(current);
}
int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
unsigned long stack_top, struct task_struct * p,
struct pt_regs *regs)
{
int ret;
p->thread = (struct thread_struct) INIT_THREAD;
ret = CHOOSE_MODE_PROC(copy_thread_tt, copy_thread_skas, nr,
clone_flags, sp, stack_top, p, regs);
if (ret || !current->thread.forking)
goto out;
clear_flushed_tls(p);
/*
* Set a new TLS for the child thread?
*/
if (clone_flags & CLONE_SETTLS)
ret = arch_copy_tls(p);
out:
return ret;
}
void initial_thread_cb(void (*proc)(void *), void *arg)
{
int save_kmalloc_ok = kmalloc_ok;
kmalloc_ok = 0;
CHOOSE_MODE_PROC(initial_thread_cb_tt, initial_thread_cb_skas, proc,
arg);
kmalloc_ok = save_kmalloc_ok;
}
unsigned long stack_sp(unsigned long page)
{
return(page + PAGE_SIZE - sizeof(void *));
}
int current_pid(void)
{
return(current->pid);
}
void default_idle(void)
{
CHOOSE_MODE(uml_idle_timer(), (void) 0);
while(1){
/* endless idle loop with no priority at all */
/*
* although we are an idle CPU, we do not want to
* get into the scheduler unnecessarily.
*/
if(need_resched())
schedule();
idle_sleep(10);
}
}
void cpu_idle(void)
{
CHOOSE_MODE(init_idle_tt(), init_idle_skas());
}
int page_size(void)
{
return(PAGE_SIZE);
}
void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
pte_t *pte_out)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
pte_t ptent;
if(task->mm == NULL)
return(ERR_PTR(-EINVAL));
pgd = pgd_offset(task->mm, addr);
if(!pgd_present(*pgd))
return(ERR_PTR(-EINVAL));
pud = pud_offset(pgd, addr);
if(!pud_present(*pud))
return(ERR_PTR(-EINVAL));
pmd = pmd_offset(pud, addr);
if(!pmd_present(*pmd))
return(ERR_PTR(-EINVAL));
pte = pte_offset_kernel(pmd, addr);
ptent = *pte;
if(!pte_present(ptent))
return(ERR_PTR(-EINVAL));
if(pte_out != NULL)
*pte_out = ptent;
return((void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK));
}
char *current_cmd(void)
{
#if defined(CONFIG_SMP) || defined(CONFIG_HIGHMEM)
return("(Unknown)");
#else
void *addr = um_virt_to_phys(current, current->mm->arg_start, NULL);
return IS_ERR(addr) ? "(Unknown)": __va((unsigned long) addr);
#endif
}
void force_sigbus(void)
{
printk(KERN_ERR "Killing pid %d because of a lack of memory\n",
current->pid);
lock_kernel();
sigaddset(&current->pending.signal, SIGBUS);
recalc_sigpending();
current->flags |= PF_SIGNALED;
do_exit(SIGBUS | 0x80);
}
void dump_thread(struct pt_regs *regs, struct user *u)
{
}
void enable_hlt(void)
{
panic("enable_hlt");
}
EXPORT_SYMBOL(enable_hlt);
void disable_hlt(void)
{
panic("disable_hlt");
}
EXPORT_SYMBOL(disable_hlt);
void *um_kmalloc(int size)
{
return kmalloc(size, GFP_KERNEL);
}
void *um_kmalloc_atomic(int size)
{
return kmalloc(size, GFP_ATOMIC);
}
void *um_vmalloc(int size)
{
return vmalloc(size);
}
void *um_vmalloc_atomic(int size)
{
return __vmalloc(size, GFP_ATOMIC | __GFP_HIGHMEM, PAGE_KERNEL);
}
int __cant_sleep(void) {
return in_atomic() || irqs_disabled() || in_interrupt();
/* Is in_interrupt() really needed? */
}
unsigned long get_fault_addr(void)
{
return((unsigned long) current->thread.fault_addr);
}
EXPORT_SYMBOL(get_fault_addr);
void not_implemented(void)
{
printk(KERN_DEBUG "Something isn't implemented in here\n");
}
EXPORT_SYMBOL(not_implemented);
int user_context(unsigned long sp)
{
unsigned long stack;
stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
return(stack != (unsigned long) current_thread);
}
extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
void do_uml_exitcalls(void)
{
exitcall_t *call;
call = &__uml_exitcall_end;
while (--call >= &__uml_exitcall_begin)
(*call)();
}
char *uml_strdup(char *string)
{
return kstrdup(string, GFP_KERNEL);
}
int copy_to_user_proc(void __user *to, void *from, int size)
{
return(copy_to_user(to, from, size));
}
int copy_from_user_proc(void *to, void __user *from, int size)
{
return(copy_from_user(to, from, size));
}
int clear_user_proc(void __user *buf, int size)
{
return(clear_user(buf, size));
}
int strlen_user_proc(char __user *str)
{
return(strlen_user(str));
}
int smp_sigio_handler(void)
{
#ifdef CONFIG_SMP
int cpu = current_thread->cpu;
IPI_handler(cpu);
if(cpu != 0)
return(1);
#endif
return(0);
}
int cpu(void)
{
return(current_thread->cpu);
}
static atomic_t using_sysemu = ATOMIC_INIT(0);
int sysemu_supported;
void set_using_sysemu(int value)
{
if (value > sysemu_supported)
return;
atomic_set(&using_sysemu, value);
}
int get_using_sysemu(void)
{
return atomic_read(&using_sysemu);
}
static int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int *eof, void *data)
{
if (snprintf(buf, size, "%d\n", get_using_sysemu()) < size) /*No overflow*/
*eof = 1;
return strlen(buf);
}
static int proc_write_sysemu(struct file *file,const char __user *buf, unsigned long count,void *data)
{
char tmp[2];
if (copy_from_user(tmp, buf, 1))
return -EFAULT;
if (tmp[0] >= '0' && tmp[0] <= '2')
set_using_sysemu(tmp[0] - '0');
return count; /*We use the first char, but pretend to write everything*/
}
int __init make_proc_sysemu(void)
{
struct proc_dir_entry *ent;
if (!sysemu_supported)
return 0;
ent = create_proc_entry("sysemu", 0600, &proc_root);
if (ent == NULL)
{
printk(KERN_WARNING "Failed to register /proc/sysemu\n");
return(0);
}
ent->read_proc = proc_read_sysemu;
ent->write_proc = proc_write_sysemu;
return 0;
}
late_initcall(make_proc_sysemu);
int singlestepping(void * t)
{
struct task_struct *task = t ? t : current;
if ( ! (task->ptrace & PT_DTRACE) )
return(0);
if (task->thread.singlestep_syscall)
return(1);
return 2;
}
/*
* Only x86 and x86_64 have an arch_align_stack().
* All other arches have "#define arch_align_stack(x) (x)"
* in their asm/system.h
* As this is included in UML from asm-um/system-generic.h,
* we can use it to behave as the subarch does.
*/
#ifndef arch_align_stack
unsigned long arch_align_stack(unsigned long sp)
{
if (randomize_va_space)
sp -= get_random_int() % 8192;
return sp & ~0xf;
}
#endif