diff options
Diffstat (limited to 'arch/um/sys-x86/ldt.c')
| -rw-r--r-- | arch/um/sys-x86/ldt.c | 502 |
1 files changed, 0 insertions, 502 deletions
diff --git a/arch/um/sys-x86/ldt.c b/arch/um/sys-x86/ldt.c deleted file mode 100644 index 3f2bf20..0000000 --- a/arch/um/sys-x86/ldt.c +++ /dev/null @@ -1,502 +0,0 @@ -/* - * 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 <asm/unistd.h> -#include "os.h" -#include "proc_mm.h" -#include "skas.h" -#include "skas_ptrace.h" -#include "sysdep/tls.h" - -extern int modify_ldt(int func, void *ptr, unsigned long bytecount); - -static long write_ldt_entry(struct mm_id *mm_idp, int func, - struct user_desc *desc, void **addr, int done) -{ - long res; - - if (proc_mm) { - /* - * This is a special handling for the case, that the mm to - * modify isn't current->active_mm. - * If this is called directly by modify_ldt, - * (current->active_mm->context.skas.u == mm_idp) - * will be true. So no call to __switch_mm(mm_idp) is done. - * If this is called in case of init_new_ldt or PTRACE_LDT, - * mm_idp won't belong to current->active_mm, but child->mm. - * So we need to switch child's mm into our userspace, then - * later switch back. - * - * Note: I'm unsure: should interrupts be disabled here? - */ - if (!current->active_mm || current->active_mm == &init_mm || - mm_idp != ¤t->active_mm->context.id) - __switch_mm(mm_idp); - } - - if (ptrace_ldt) { - struct ptrace_ldt ldt_op = (struct ptrace_ldt) { - .func = func, - .ptr = desc, - .bytecount = sizeof(*desc)}; - u32 cpu; - int pid; - - if (!proc_mm) - pid = mm_idp->u.pid; - else { - cpu = get_cpu(); - pid = userspace_pid[cpu]; - } - - res = os_ptrace_ldt(pid, 0, (unsigned long) &ldt_op); - - if (proc_mm) - put_cpu(); - } - else { - void *stub_addr; - res = syscall_stub_data(mm_idp, (unsigned long *)desc, - (sizeof(*desc) + sizeof(long) - 1) & - ~(sizeof(long) - 1), - addr, &stub_addr); - if (!res) { - unsigned long args[] = { func, - (unsigned long)stub_addr, - sizeof(*desc), - 0, 0, 0 }; - res = run_syscall_stub(mm_idp, __NR_modify_ldt, args, - 0, addr, done); - } - } - - if (proc_mm) { - /* - * This is the second part of special handling, that makes - * PTRACE_LDT possible to implement. - */ - if (current->active_mm && current->active_mm != &init_mm && - mm_idp != ¤t->active_mm->context.id) - __switch_mm(¤t->active_mm->context.id); - } - - return res; -} - -static long read_ldt_from_host(void __user * ptr, unsigned long bytecount) -{ - int res, n; - struct ptrace_ldt ptrace_ldt = (struct ptrace_ldt) { - .func = 0, - .bytecount = bytecount, - .ptr = kmalloc(bytecount, GFP_KERNEL)}; - u32 cpu; - - if (ptrace_ldt.ptr == NULL) - return -ENOMEM; - - /* - * This is called from sys_modify_ldt only, so userspace_pid gives - * us the right number - */ - - cpu = get_cpu(); - res = os_ptrace_ldt(userspace_pid[cpu], 0, (unsigned long) &ptrace_ldt); - put_cpu(); - if (res < 0) - goto out; - - n = copy_to_user(ptr, ptrace_ldt.ptr, res); - if (n != 0) - res = -EFAULT; - - out: - kfree(ptrace_ldt.ptr); - - return res; -} - -/* - * 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.ldt; - - if (!ldt->entry_count) - goto out; - if (bytecount > LDT_ENTRY_SIZE*LDT_ENTRIES) - bytecount = LDT_ENTRY_SIZE*LDT_ENTRIES; - err = bytecount; - - if (ptrace_ldt) - return read_ldt_from_host(ptr, 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.ldt; - struct mm_id * mm_idp = ¤t->mm->context.id; - int i, err; - struct user_desc ldt_info; - struct ldt_entry entry0, *ldt_p; - void *addr = NULL; - - 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; - } - - if (!ptrace_ldt) - mutex_lock(&ldt->lock); - - err = write_ldt_entry(mm_idp, func, &ldt_info, &addr, 1); - if (err) - goto out_unlock; - else if (ptrace_ldt) { - /* With PTRACE_LDT available, this is used as a flag only */ - ldt->entry_count = 1; - goto out; - } - - 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, &addr, 1); - 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; - void *addr = NULL; - struct proc_mm_op copy; - - - if (!ptrace_ldt) - mutex_init(&new_mm->ldt.lock); - - if (!from_mm) { - memset(&desc, 0, sizeof(desc)); - /* - * We have to initialize a clean ldt. - */ - if (proc_mm) { - /* - * If the new mm was created using proc_mm, host's - * default-ldt currently is assigned, which normally - * contains the call-gates for lcall7 and lcall27. - * To remove these gates, we simply write an empty - * entry as number 0 to the host. - */ - err = write_ldt_entry(&new_mm->id, 1, &desc, &addr, 1); - } - else{ - /* - * 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; - err = write_ldt_entry(&new_mm->id, 1, &desc, - &addr, *(num_p + 1) == -1); - if (err) - break; - } - } - new_mm->ldt.entry_count = 0; - - goto out; - } - - if (proc_mm) { - /* - * We have a valid from_mm, so we now have to copy the LDT of - * from_mm to new_mm, because using proc_mm an new mm with - * an empty/default LDT was created in new_mm() - */ - copy = ((struct proc_mm_op) { .op = MM_COPY_SEGMENTS, - .u = - { .copy_segments = - from_mm->id.u.mm_fd } } ); - i = os_write_file(new_mm->id.u.mm_fd, ©, sizeof(copy)); - if (i != sizeof(copy)) - printk(KERN_ERR "new_mm : /proc/mm copy_segments " - "failed, err = %d\n", -i); - } - - if (!ptrace_ldt) { - /* - * 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->ldt.lock); - if (from_mm->ldt.entry_count <= LDT_DIRECT_ENTRIES) - memcpy(new_mm->ldt.u.entries, from_mm->ldt.u.entries, - sizeof(new_mm->ldt.u.entries)); - else { - i = from_mm->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->ldt.u.pages[i] = - (struct ldt_entry *) page; - memcpy(new_mm->ldt.u.pages[i], - from_mm->ldt.u.pages[i], PAGE_SIZE); - } - } - new_mm->ldt.entry_count = from_mm->ldt.entry_count; - mutex_unlock(&from_mm->ldt.lock); - } - - out: - return err; -} - - -void free_ldt(struct mm_context *mm) -{ - int i; - - if (!ptrace_ldt && mm->ldt.entry_count > LDT_DIRECT_ENTRIES) { - i = mm->ldt.entry_count / LDT_ENTRIES_PER_PAGE; - while (i-- > 0) - free_page((long) mm->ldt.u.pages[i]); - } - mm->ldt.entry_count = 0; -} - -int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount) -{ - return do_modify_ldt_skas(func, ptr, bytecount); -} |