summaryrefslogtreecommitdiffstats
path: root/arch/um/sys-i386/ldt.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/um/sys-i386/ldt.c')
-rw-r--r--arch/um/sys-i386/ldt.c502
1 files changed, 0 insertions, 502 deletions
diff --git a/arch/um/sys-i386/ldt.c b/arch/um/sys-i386/ldt.c
deleted file mode 100644
index 3f2bf208d884..000000000000
--- a/arch/um/sys-i386/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 != &current->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 != &current->active_mm->context.id)
- __switch_mm(&current->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 = &current->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 = &current->mm->context.ldt;
- struct mm_id * mm_idp = &current->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, &copy, 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);
-}
OpenPOWER on IntegriCloud