+++ /dev/null
-/*
- * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
- * Licensed under the GPL
- */
-
-#include <linux/mm.h>
-#include <linux/sched.h>
-#include <linux/slab.h>
-#include <linux/syscalls.h>
-#include <linux/uaccess.h>
-#include <asm/unistd.h>
-#include <os.h>
-#include <skas.h>
-#include <sysdep/tls.h>
-#include <stub-data.h>
-
-static inline int modify_ldt (int func, void *ptr, unsigned long bytecount)
-{
- return syscall(__NR_modify_ldt, func, ptr, bytecount);
-}
-
-static void write_ldt_entry(struct mm_id *mm_idp, int func,
- struct user_desc *desc)
-{
- struct stub_syscall *sc;
-
- sc = syscall_stub_alloc(mm_idp);
- sc->syscall = STUB_SYSCALL_LDT;
- sc->ldt.func = func;
- memcpy(&sc->ldt.desc, desc, sizeof(*desc));
-}
-
-/*
- * In skas mode, we hold our own ldt data in UML.
- * Thus, the code implementing sys_modify_ldt_skas
- * is very similar to (and mostly stolen from) sys_modify_ldt
- * for arch/i386/kernel/ldt.c
- * The routines copied and modified in part are:
- * - read_ldt
- * - read_default_ldt
- * - write_ldt
- * - sys_modify_ldt_skas
- */
-
-static int read_ldt(void __user * ptr, unsigned long bytecount)
-{
- int i, err = 0;
- unsigned long size;
- uml_ldt_t *ldt = ¤t->mm->context.arch.ldt;
-
- if (!ldt->entry_count)
- goto out;
- if (bytecount > LDT_ENTRY_SIZE*LDT_ENTRIES)
- bytecount = LDT_ENTRY_SIZE*LDT_ENTRIES;
- err = bytecount;
-
- mutex_lock(&ldt->lock);
- if (ldt->entry_count <= LDT_DIRECT_ENTRIES) {
- size = LDT_ENTRY_SIZE*LDT_DIRECT_ENTRIES;
- if (size > bytecount)
- size = bytecount;
- if (copy_to_user(ptr, ldt->u.entries, size))
- err = -EFAULT;
- bytecount -= size;
- ptr += size;
- }
- else {
- for (i=0; i<ldt->entry_count/LDT_ENTRIES_PER_PAGE && bytecount;
- i++) {
- size = PAGE_SIZE;
- if (size > bytecount)
- size = bytecount;
- if (copy_to_user(ptr, ldt->u.pages[i], size)) {
- err = -EFAULT;
- break;
- }
- bytecount -= size;
- ptr += size;
- }
- }
- mutex_unlock(&ldt->lock);
-
- if (bytecount == 0 || err == -EFAULT)
- goto out;
-
- if (clear_user(ptr, bytecount))
- err = -EFAULT;
-
-out:
- return err;
-}
-
-static int read_default_ldt(void __user * ptr, unsigned long bytecount)
-{
- int err;
-
- if (bytecount > 5*LDT_ENTRY_SIZE)
- bytecount = 5*LDT_ENTRY_SIZE;
-
- err = bytecount;
- /*
- * UML doesn't support lcall7 and lcall27.
- * So, we don't really have a default ldt, but emulate
- * an empty ldt of common host default ldt size.
- */
- if (clear_user(ptr, bytecount))
- err = -EFAULT;
-
- return err;
-}
-
-static int write_ldt(void __user * ptr, unsigned long bytecount, int func)
-{
- uml_ldt_t *ldt = ¤t->mm->context.arch.ldt;
- struct mm_id * mm_idp = ¤t->mm->context.id;
- int i, err;
- struct user_desc ldt_info;
- struct ldt_entry entry0, *ldt_p;
-
- err = -EINVAL;
- if (bytecount != sizeof(ldt_info))
- goto out;
- err = -EFAULT;
- if (copy_from_user(&ldt_info, ptr, sizeof(ldt_info)))
- goto out;
-
- err = -EINVAL;
- if (ldt_info.entry_number >= LDT_ENTRIES)
- goto out;
- if (ldt_info.contents == 3) {
- if (func == 1)
- goto out;
- if (ldt_info.seg_not_present == 0)
- goto out;
- }
-
- mutex_lock(&ldt->lock);
-
- write_ldt_entry(mm_idp, func, &ldt_info);
- err = syscall_stub_flush(mm_idp);
- if (err)
- goto out_unlock;
-
- if (ldt_info.entry_number >= ldt->entry_count &&
- ldt_info.entry_number >= LDT_DIRECT_ENTRIES) {
- for (i=ldt->entry_count/LDT_ENTRIES_PER_PAGE;
- i*LDT_ENTRIES_PER_PAGE <= ldt_info.entry_number;
- i++) {
- if (i == 0)
- memcpy(&entry0, ldt->u.entries,
- sizeof(entry0));
- ldt->u.pages[i] = (struct ldt_entry *)
- __get_free_page(GFP_KERNEL|__GFP_ZERO);
- if (!ldt->u.pages[i]) {
- err = -ENOMEM;
- /* Undo the change in host */
- memset(&ldt_info, 0, sizeof(ldt_info));
- write_ldt_entry(mm_idp, 1, &ldt_info);
- err = syscall_stub_flush(mm_idp);
- goto out_unlock;
- }
- if (i == 0) {
- memcpy(ldt->u.pages[0], &entry0,
- sizeof(entry0));
- memcpy(ldt->u.pages[0]+1, ldt->u.entries+1,
- sizeof(entry0)*(LDT_DIRECT_ENTRIES-1));
- }
- ldt->entry_count = (i + 1) * LDT_ENTRIES_PER_PAGE;
- }
- }
- if (ldt->entry_count <= ldt_info.entry_number)
- ldt->entry_count = ldt_info.entry_number + 1;
-
- if (ldt->entry_count <= LDT_DIRECT_ENTRIES)
- ldt_p = ldt->u.entries + ldt_info.entry_number;
- else
- ldt_p = ldt->u.pages[ldt_info.entry_number/LDT_ENTRIES_PER_PAGE] +
- ldt_info.entry_number%LDT_ENTRIES_PER_PAGE;
-
- if (ldt_info.base_addr == 0 && ldt_info.limit == 0 &&
- (func == 1 || LDT_empty(&ldt_info))) {
- ldt_p->a = 0;
- ldt_p->b = 0;
- }
- else{
- if (func == 1)
- ldt_info.useable = 0;
- ldt_p->a = LDT_entry_a(&ldt_info);
- ldt_p->b = LDT_entry_b(&ldt_info);
- }
- err = 0;
-
-out_unlock:
- mutex_unlock(&ldt->lock);
-out:
- return err;
-}
-
-static long do_modify_ldt_skas(int func, void __user *ptr,
- unsigned long bytecount)
-{
- int ret = -ENOSYS;
-
- switch (func) {
- case 0:
- ret = read_ldt(ptr, bytecount);
- break;
- case 1:
- case 0x11:
- ret = write_ldt(ptr, bytecount, func);
- break;
- case 2:
- ret = read_default_ldt(ptr, bytecount);
- break;
- }
- return ret;
-}
-
-static DEFINE_SPINLOCK(host_ldt_lock);
-static short dummy_list[9] = {0, -1};
-static short * host_ldt_entries = NULL;
-
-static void ldt_get_host_info(void)
-{
- long ret;
- struct ldt_entry * ldt;
- short *tmp;
- int i, size, k, order;
-
- spin_lock(&host_ldt_lock);
-
- if (host_ldt_entries != NULL) {
- spin_unlock(&host_ldt_lock);
- return;
- }
- host_ldt_entries = dummy_list+1;
-
- spin_unlock(&host_ldt_lock);
-
- for (i = LDT_PAGES_MAX-1, order=0; i; i>>=1, order++)
- ;
-
- ldt = (struct ldt_entry *)
- __get_free_pages(GFP_KERNEL|__GFP_ZERO, order);
- if (ldt == NULL) {
- printk(KERN_ERR "ldt_get_host_info: couldn't allocate buffer "
- "for host ldt\n");
- return;
- }
-
- ret = modify_ldt(0, ldt, (1<<order)*PAGE_SIZE);
- if (ret < 0) {
- printk(KERN_ERR "ldt_get_host_info: couldn't read host ldt\n");
- goto out_free;
- }
- if (ret == 0) {
- /* default_ldt is active, simply write an empty entry 0 */
- host_ldt_entries = dummy_list;
- goto out_free;
- }
-
- for (i=0, size=0; i<ret/LDT_ENTRY_SIZE; i++) {
- if (ldt[i].a != 0 || ldt[i].b != 0)
- size++;
- }
-
- if (size < ARRAY_SIZE(dummy_list))
- host_ldt_entries = dummy_list;
- else {
- size = (size + 1) * sizeof(dummy_list[0]);
- tmp = kmalloc(size, GFP_KERNEL);
- if (tmp == NULL) {
- printk(KERN_ERR "ldt_get_host_info: couldn't allocate "
- "host ldt list\n");
- goto out_free;
- }
- host_ldt_entries = tmp;
- }
-
- for (i=0, k=0; i<ret/LDT_ENTRY_SIZE; i++) {
- if (ldt[i].a != 0 || ldt[i].b != 0)
- host_ldt_entries[k++] = i;
- }
- host_ldt_entries[k] = -1;
-
-out_free:
- free_pages((unsigned long)ldt, order);
-}
-
-long init_new_ldt(struct mm_context *new_mm, struct mm_context *from_mm)
-{
- struct user_desc desc;
- short * num_p;
- int i;
- long page, err=0;
-
-
- mutex_init(&new_mm->arch.ldt.lock);
-
- if (!from_mm) {
- memset(&desc, 0, sizeof(desc));
- /*
- * Now we try to retrieve info about the ldt, we
- * inherited from the host. All ldt-entries found
- * will be reset in the following loop
- */
- ldt_get_host_info();
- for (num_p=host_ldt_entries; *num_p != -1; num_p++) {
- desc.entry_number = *num_p;
- write_ldt_entry(&new_mm->id, 1, &desc);
- }
- err = syscall_stub_flush(&new_mm->id);
- new_mm->arch.ldt.entry_count = 0;
-
- goto out;
- }
-
- /*
- * Our local LDT is used to supply the data for
- * modify_ldt(READLDT), if PTRACE_LDT isn't available,
- * i.e., we have to use the stub for modify_ldt, which
- * can't handle the big read buffer of up to 64kB.
- */
- mutex_lock(&from_mm->arch.ldt.lock);
- if (from_mm->arch.ldt.entry_count <= LDT_DIRECT_ENTRIES)
- memcpy(new_mm->arch.ldt.u.entries, from_mm->arch.ldt.u.entries,
- sizeof(new_mm->arch.ldt.u.entries));
- else {
- i = from_mm->arch.ldt.entry_count / LDT_ENTRIES_PER_PAGE;
- while (i-->0) {
- page = __get_free_page(GFP_KERNEL|__GFP_ZERO);
- if (!page) {
- err = -ENOMEM;
- break;
- }
- new_mm->arch.ldt.u.pages[i] =
- (struct ldt_entry *) page;
- memcpy(new_mm->arch.ldt.u.pages[i],
- from_mm->arch.ldt.u.pages[i], PAGE_SIZE);
- }
- }
- new_mm->arch.ldt.entry_count = from_mm->arch.ldt.entry_count;
- mutex_unlock(&from_mm->arch.ldt.lock);
-
- out:
- return err;
-}
-
-
-void free_ldt(struct mm_context *mm)
-{
- int i;
-
- if (mm->arch.ldt.entry_count > LDT_DIRECT_ENTRIES) {
- i = mm->arch.ldt.entry_count / LDT_ENTRIES_PER_PAGE;
- while (i-- > 0)
- free_page((long) mm->arch.ldt.u.pages[i]);
- }
- mm->arch.ldt.entry_count = 0;
-}
-
-SYSCALL_DEFINE3(modify_ldt, int , func , void __user * , ptr ,
- unsigned long , bytecount)
-{
- /* See non-um modify_ldt() for why we do this cast */
- return (unsigned int)do_modify_ldt_skas(func, ptr, bytecount);
-}
projects / thirdparty / kernel / linux.git / commitdiff
