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[PATCH] uml: maintain own LDT entries

Browse Source 
Patch imlements full LDT handling in SKAS:
 * UML holds it's own LDT table, used to deliver data on
   modify_ldt(READ)
 * UML disables the default_ldt, inherited from the host (SKAS3)
   or resets LDT entries, set by host's clib and inherited in
   SKAS0
 * A new global variable skas_needs_stub is inserted, that
   can be used to decide, whether stub-pages must be supported
   or not.
 * Uses the syscall-stub to replace missing PTRACE_LDT (therefore,
   write_ldt_entry needs to be modified)

Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Bodo Stroesser 2005-11-07 00:58:55 -08:00 committed by Linus Torvalds
parent e763b793f7
commit 858259cf7d
13 changed files with 724 additions and 141 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/um/kernel/skas/include/mmu-skas.h
View File

@ -8,6 +8,7 @@
#include "linux/config.h"
#include "mm_id.h"
#include "asm/ldt.h"
struct mmu_context_skas {
struct mm_id id;
@ -15,6 +16,7 @@ struct mmu_context_skas {
#ifdef CONFIG_3_LEVEL_PGTABLES
unsigned long last_pmd;
#endif
uml_ldt_t ldt;
};
extern void switch_mm_skas(struct mm_id * mm_idp);

3
arch/um/kernel/skas/include/skas.h
View File

@ -10,7 +10,8 @@
#include "sysdep/ptrace.h"
extern int userspace_pid[];
extern int proc_mm, ptrace_faultinfo;
extern int proc_mm, ptrace_faultinfo, ptrace_ldt;
extern int skas_needs_stub;
extern void switch_threads(void *me, void *next);
extern void thread_wait(void *sw, void *fb);

2
arch/um/kernel/skas/mem.c
View File

@ -20,7 +20,7 @@ unsigned long set_task_sizes_skas(int arg, unsigned long *host_size_out,
*task_size_out = CONFIG_HOST_TASK_SIZE;
#else
*host_size_out = top;
if (proc_mm && ptrace_faultinfo)
if (!skas_needs_stub)
*task_size_out = top;
else *task_size_out = CONFIG_STUB_START & PGDIR_MASK;
#endif

44
arch/um/kernel/skas/mmu.c
View File

@ -15,6 +15,7 @@
#include "asm/mmu.h"
#include "asm/pgalloc.h"
#include "asm/pgtable.h"
#include "asm/ldt.h"
#include "os.h"
#include "skas.h"
@ -74,13 +75,12 @@ static int init_stub_pte(struct mm_struct *mm, unsigned long proc,
int init_new_context_skas(struct task_struct *task, struct mm_struct *mm)
{
struct mm_struct *cur_mm = current->mm;
struct mm_id *cur_mm_id = &cur_mm->context.skas.id;
struct mm_id *mm_id = &mm->context.skas.id;
struct mmu_context_skas *from_mm = NULL;
struct mmu_context_skas *to_mm = &mm->context.skas;
unsigned long stack = 0;
int from, ret = -ENOMEM;
int from_fd, ret = -ENOMEM;
if(!proc_mm || !ptrace_faultinfo){
if(skas_needs_stub){
stack = get_zeroed_page(GFP_KERNEL);
if(stack == 0)
goto out;
@ -102,33 +102,43 @@ int init_new_context_skas(struct task_struct *task, struct mm_struct *mm)
mm->nr_ptes--;
}
mm_id->stack = stack;
to_mm->id.stack = stack;
if(current->mm != NULL && current->mm != &init_mm)
from_mm = &current->mm->context.skas;
if(proc_mm){
if((cur_mm != NULL) && (cur_mm != &init_mm))
from = cur_mm_id->u.mm_fd;
else from = -1;
if(from_mm)
from_fd = from_mm->id.u.mm_fd;
else from_fd = -1;
ret = new_mm(from, stack);
ret = new_mm(from_fd, stack);
if(ret < 0){
printk("init_new_context_skas - new_mm failed, "
"errno = %d\n", ret);
goto out_free;
}
mm_id->u.mm_fd = ret;
to_mm->id.u.mm_fd = ret;
}
else {
if((cur_mm != NULL) && (cur_mm != &init_mm))
mm_id->u.pid = copy_context_skas0(stack,
cur_mm_id->u.pid);
else mm_id->u.pid = start_userspace(stack);
if(from_mm)
to_mm->id.u.pid = copy_context_skas0(stack,
from_mm->id.u.pid);
else to_mm->id.u.pid = start_userspace(stack);
}
ret = init_new_ldt(to_mm, from_mm);
if(ret < 0){
printk("init_new_context_skas - init_ldt"
" failed, errno = %d\n", ret);
goto out_free;
}
return 0;
out_free:
if(mm_id->stack != 0)
free_page(mm_id->stack);
if(to_mm->id.stack != 0)
free_page(to_mm->id.stack);
out:
return ret;
}

6
arch/um/kernel/skas/process.c
View File

@ -381,9 +381,9 @@ int copy_context_skas0(unsigned long new_stack, int pid)
}
/*
* This is used only, if proc_mm is available, while PTRACE_FAULTINFO
* isn't. Opening /proc/mm creates a new mm_context, which lacks the stub-pages
* Thus, we map them using /proc/mm-fd
* This is used only, if stub pages are needed, while proc_mm is
* availabl. Opening /proc/mm creates a new mm_context, which lacks
* the stub-pages. Thus, we map them using /proc/mm-fd
*/
void map_stub_pages(int fd, unsigned long code,
unsigned long data, unsigned long stack)

2
arch/um/kernel/skas/process_kern.c
View File

@ -145,7 +145,7 @@ int new_mm(int from, unsigned long stack)
"err = %d\n", -n);
}
if(!ptrace_faultinfo)
if(skas_needs_stub)
map_stub_pages(fd, CONFIG_STUB_CODE, CONFIG_STUB_DATA, stack);
return(fd);

75
arch/um/os-Linux/start_up.c
View File

@ -135,7 +135,9 @@ static int stop_ptraced_child(int pid, void *stack, int exitcode,
}
int ptrace_faultinfo = 1;
int ptrace_ldt = 1;
int proc_mm = 1;
int skas_needs_stub = 0;
static int __init skas0_cmd_param(char *str, int* add)
{
@ -352,14 +354,26 @@ __uml_setup("noptracefaultinfo", noptracefaultinfo_cmd_param,
" it. To support PTRACE_FAULTINFO, the host needs to be patched\n"
" using the current skas3 patch.\n\n");
static int __init noptraceldt_cmd_param(char *str, int* add)
{
ptrace_ldt = 0;
return 0;
}
__uml_setup("noptraceldt", noptraceldt_cmd_param,
"noptraceldt\n"
" Turns off usage of PTRACE_LDT, even if host supports it.\n"
" To support PTRACE_LDT, the host needs to be patched using\n"
" the current skas3 patch.\n\n");
#ifdef UML_CONFIG_MODE_SKAS
static inline void check_skas3_ptrace_support(void)
static inline void check_skas3_ptrace_faultinfo(void)
{
struct ptrace_faultinfo fi;
void *stack;
int pid, n;
printf("Checking for the skas3 patch in the host...");
printf(" - PTRACE_FAULTINFO...");
pid = start_ptraced_child(&stack);
n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
@ -381,9 +395,49 @@ static inline void check_skas3_ptrace_support(void)
stop_ptraced_child(pid, stack, 1, 1);
}
int can_do_skas(void)
static inline void check_skas3_ptrace_ldt(void)
{
printf("Checking for /proc/mm...");
#ifdef PTRACE_LDT
void *stack;
int pid, n;
unsigned char ldtbuf[40];
struct ptrace_ldt ldt_op = (struct ptrace_ldt) {
.func = 2, /* read default ldt */
.ptr = ldtbuf,
.bytecount = sizeof(ldtbuf)};
printf(" - PTRACE_LDT...");
pid = start_ptraced_child(&stack);
n = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op);
if (n < 0) {
if(errno == EIO)
printf("not found\n");
else {
perror("not found");
}
ptrace_ldt = 0;
}
else {
if(ptrace_ldt)
printf("found\n");
else
printf("found, but use is disabled\n");
}
stop_ptraced_child(pid, stack, 1, 1);
#else
/* PTRACE_LDT might be disabled via cmdline option.
* We want to override this, else we might use the stub
* without real need
*/
ptrace_ldt = 1;
#endif
}
static inline void check_skas3_proc_mm(void)
{
printf(" - /proc/mm...");
if (os_access("/proc/mm", OS_ACC_W_OK) < 0) {
proc_mm = 0;
printf("not found\n");
@ -394,8 +448,19 @@ int can_do_skas(void)
else
printf("found\n");
}
}
int can_do_skas(void)
{
printf("Checking for the skas3 patch in the host:\n");
check_skas3_proc_mm();
check_skas3_ptrace_faultinfo();
check_skas3_ptrace_ldt();
if(!proc_mm || !ptrace_faultinfo || !ptrace_ldt)
skas_needs_stub = 1;
check_skas3_ptrace_support();
return 1;
}
#else

7
arch/um/scripts/Makefile.rules
View File

@ -26,8 +26,13 @@ define unprofile
$(patsubst -pg,,$(patsubst -fprofile-arcs -ftest-coverage,,$(1)))
endef
# cmd_make_link checks to see if the $(foo-dir) variable starts with a /. If
# so, it's considered to be a path relative to $(srcdir) rather than
# $(srcdir)/arch/$(SUBARCH). This is because x86_64 wants to get ldt.c from
# arch/um/sys-i386 rather than arch/i386 like the other borrowed files. So,
# it sets $(ldt.c-dir) to /arch/um/sys-i386.
quiet_cmd_make_link = SYMLINK $@
cmd_make_link = ln -sf $(srctree)/arch/$(SUBARCH)/$($(notdir $@)-dir)/$(notdir $@) $@
cmd_make_link = rm -f $@; ln -sf $(srctree)$(if $(filter-out /%,$($(notdir $@)-dir)),/arch/$(SUBARCH))/$($(notdir $@)-dir)/$(notdir $@) $@
# this needs to be before the foreach, because targets does not accept
# complete paths like $(obj)/$(f). To make sure this works, use a := assignment

506
arch/um/sys-i386/ldt.c
View File

@ -3,53 +3,26 @@
* Licensed under the GPL
*/
#include "linux/stddef.h"
#include "linux/config.h"
#include "linux/sched.h"
#include "linux/slab.h"
#include "linux/types.h"
#include "linux/errno.h"
#include "asm/uaccess.h"
#include "asm/ptrace.h"
#include "asm/smp.h"
#include "asm/ldt.h"
#include "asm/unistd.h"
#include "choose-mode.h"
#include "kern.h"
#include "mode_kern.h"
#ifdef CONFIG_MODE_TT
extern int modify_ldt(int func, void *ptr, unsigned long bytecount);
static int do_modify_ldt_tt(int func, void *ptr, unsigned long bytecount)
{
return modify_ldt(func, ptr, bytecount);
}
#ifdef CONFIG_MODE_TT
#endif
#ifdef CONFIG_MODE_SKAS
#include "skas.h"
#include "skas_ptrace.h"
static int do_modify_ldt_skas(int func, void *ptr, unsigned long bytecount)
{
struct ptrace_ldt ldt;
u32 cpu;
int res;
ldt = ((struct ptrace_ldt) { .func = func,
.ptr = ptr,
.bytecount = bytecount });
cpu = get_cpu();
res = ptrace(PTRACE_LDT, userspace_pid[cpu], 0, (unsigned long) &ldt);
put_cpu();
return res;
}
#endif
int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount)
static long do_modify_ldt_tt(int func, void __user *ptr,
unsigned long bytecount)
{
struct user_desc info;
int res = 0;
@ -89,8 +62,7 @@ int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount)
goto out;
}
res = CHOOSE_MODE_PROC(do_modify_ldt_tt, do_modify_ldt_skas, func,
p, bytecount);
res = modify_ldt(func, p, bytecount);
if(res < 0)
goto out;
@ -108,3 +80,467 @@ out:
kfree(buf);
return res;
}
#endif
#ifdef CONFIG_MODE_SKAS
#include "skas.h"
#include "skas_ptrace.h"
#include "asm/mmu_context.h"
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_skas(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 unshure: should interrupts be disabled here?
*/
if(!current->active_mm || current->active_mm == &init_mm ||
mm_idp != &current->active_mm->context.skas.id)
switch_mm_skas(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 = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op);
if(res)
res = errno;
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.skas.id)
switch_mm_skas(&current->active_mm->context.skas.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 = (void *)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 = ptrace(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.skas.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);
}
down(&ldt->semaphore);
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->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->pages[i], size)){
err = -EFAULT;
break;
}
bytecount -= size;
ptr += size;
}
}
up(&ldt->semaphore);
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.skas.ldt;
struct mm_id * mm_idp = &current->mm->context.skas.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)
down(&ldt->semaphore);
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->entries, sizeof(entry0));
ldt->pages[i] = (struct ldt_entry *)
__get_free_page(GFP_KERNEL|__GFP_ZERO);
if(!ldt->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->pages[0], &entry0, sizeof(entry0));
memcpy(ldt->pages[0]+1, ldt->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->entries + ldt_info.entry_number;
else
ldt_p = ldt->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:
up(&ldt->semaphore);
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;
}
short dummy_list[9] = {0, -1};
short * host_ldt_entries = NULL;
void ldt_get_host_info(void)
{
long ret;
struct ldt_entry * ldt;
int i, size, k, order;
host_ldt_entries = dummy_list+1;
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("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("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 < sizeof(dummy_list)/sizeof(dummy_list[0])) {
host_ldt_entries = dummy_list;
}
else {
size = (size + 1) * sizeof(dummy_list[0]);
host_ldt_entries = (short *)kmalloc(size, GFP_KERNEL);
if(host_ldt_entries == NULL) {
printk("ldt_get_host_info: couldn't allocate host ldt list\n");
goto out_free;
}
}
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 mmu_context_skas * new_mm,
struct mmu_context_skas * from_mm)
{
struct user_desc desc;
short * num_p;
int i;
long page, err=0;
void *addr = NULL;
memset(&desc, 0, sizeof(desc));
if(!ptrace_ldt)
init_MUTEX(&new_mm->ldt.semaphore);
if(!from_mm){
/*
* 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
*/
if(host_ldt_entries == NULL)
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;
}
else 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.
*/
down(&from_mm->ldt.semaphore);
if(from_mm->ldt.entry_count <= LDT_DIRECT_ENTRIES){
memcpy(new_mm->ldt.entries, from_mm->ldt.entries,
sizeof(new_mm->ldt.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.pages[i] = (struct ldt_entry*)page;
memcpy(new_mm->ldt.pages[i],
from_mm->ldt.pages[i], PAGE_SIZE);
}
}
new_mm->ldt.entry_count = from_mm->ldt.entry_count;
up(&from_mm->ldt.semaphore);
}
return err;
}
void free_ldt(struct mmu_context_skas * 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.pages[i]);
}
}
mm->ldt.entry_count = 0;
}
#endif
int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount)
{
return(CHOOSE_MODE_PROC(do_modify_ldt_tt, do_modify_ldt_skas, func,
ptr, bytecount));
}

5
arch/um/sys-x86_64/Makefile
View File

@ -5,7 +5,7 @@
#
#XXX: why into lib-y?
lib-y = bitops.o bugs.o csum-partial.o delay.o fault.o mem.o memcpy.o \
lib-y = bitops.o bugs.o csum-partial.o delay.o fault.o ldt.o mem.o memcpy.o \
ptrace.o ptrace_user.o sigcontext.o signal.o stub.o \
stub_segv.o syscalls.o syscall_table.o sysrq.o thunk.o
@ -14,7 +14,7 @@ obj-$(CONFIG_MODULES) += module.o um_module.o
USER_OBJS := ptrace_user.o sigcontext.o
SYMLINKS = bitops.c csum-copy.S csum-partial.c csum-wrappers.c memcpy.S \
SYMLINKS = bitops.c csum-copy.S csum-partial.c csum-wrappers.c ldt.c memcpy.S \
thunk.S module.c
include arch/um/scripts/Makefile.rules
@ -23,6 +23,7 @@ bitops.c-dir = lib
csum-copy.S-dir = lib
csum-partial.c-dir = lib
csum-wrappers.c-dir = lib
ldt.c-dir = /arch/um/sys-i386
memcpy.S-dir = lib
thunk.S-dir = lib
module.c-dir = kernel

75
arch/um/sys-x86_64/syscalls.c
View File

@ -28,81 +28,6 @@ asmlinkage long sys_uname64(struct new_utsname __user * name)
return err ? -EFAULT : 0;
}
#ifdef CONFIG_MODE_TT
extern int modify_ldt(int func, void *ptr, unsigned long bytecount);
long sys_modify_ldt_tt(int func, void *ptr, unsigned long bytecount)
{
/* XXX This should check VERIFY_WRITE depending on func, check this
* in i386 as well.
*/
if (!access_ok(VERIFY_READ, ptr, bytecount))
return -EFAULT;
return(modify_ldt(func, ptr, bytecount));
}
#endif
#ifdef CONFIG_MODE_SKAS
extern int userspace_pid[];
#include "skas_ptrace.h"
long sys_modify_ldt_skas(int func, void *ptr, unsigned long bytecount)
{
struct ptrace_ldt ldt;
void *buf;
int res, n;
buf = kmalloc(bytecount, GFP_KERNEL);
if(buf == NULL)
return(-ENOMEM);
res = 0;
switch(func){
case 1:
case 0x11:
res = copy_from_user(buf, ptr, bytecount);
break;
}
if(res != 0){
res = -EFAULT;
goto out;
}
ldt = ((struct ptrace_ldt) { .func = func,
.ptr = buf,
.bytecount = bytecount });
#warning Need to look up userspace_pid by cpu
res = ptrace(PTRACE_LDT, userspace_pid[0], 0, (unsigned long) &ldt);
if(res < 0)
goto out;
switch(func){
case 0:
case 2:
n = res;
res = copy_to_user(ptr, buf, n);
if(res != 0)
res = -EFAULT;
else
res = n;
break;
}
out:
kfree(buf);
return(res);
}
#endif
long sys_modify_ldt(int func, void *ptr, unsigned long bytecount)
{
return(CHOOSE_MODE_PROC(sys_modify_ldt_tt, sys_modify_ldt_skas, func,
ptr, bytecount));
}
#ifdef CONFIG_MODE_TT
extern long arch_prctl(int code, unsigned long addr);

69
include/asm-um/ldt-i386.h Normal file
View File

@ -0,0 +1,69 @@
/*
* Copyright (C) 2004 Fujitsu Siemens Computers GmbH
* Licensed under the GPL
*
* Author: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
*/
#ifndef __ASM_LDT_I386_H
#define __ASM_LDT_I386_H
#include "asm/semaphore.h"
#include "asm/arch/ldt.h"
struct mmu_context_skas;
extern void ldt_host_info(void);
extern long init_new_ldt(struct mmu_context_skas * to_mm,
struct mmu_context_skas * from_mm);
extern void free_ldt(struct mmu_context_skas * mm);
#define LDT_PAGES_MAX \
((LDT_ENTRIES * LDT_ENTRY_SIZE)/PAGE_SIZE)
#define LDT_ENTRIES_PER_PAGE \
(PAGE_SIZE/LDT_ENTRY_SIZE)
#define LDT_DIRECT_ENTRIES \
((LDT_PAGES_MAX*sizeof(void *))/LDT_ENTRY_SIZE)
struct ldt_entry {
__u32 a;
__u32 b;
};
typedef struct uml_ldt {
int entry_count;
struct semaphore semaphore;
union {
struct ldt_entry * pages[LDT_PAGES_MAX];
struct ldt_entry entries[LDT_DIRECT_ENTRIES];
};
} uml_ldt_t;
/*
* macros stolen from include/asm-i386/desc.h
*/
#define LDT_entry_a(info) \
((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
#define LDT_entry_b(info) \
(((info)->base_addr & 0xff000000) | \
(((info)->base_addr & 0x00ff0000) >> 16) | \
((info)->limit & 0xf0000) | \
(((info)->read_exec_only ^ 1) << 9) | \
((info)->contents << 10) | \
(((info)->seg_not_present ^ 1) << 15) | \
((info)->seg_32bit << 22) | \
((info)->limit_in_pages << 23) | \
((info)->useable << 20) | \
0x7000)
#define LDT_empty(info) (\
(info)->base_addr == 0 && \
(info)->limit == 0 && \
(info)->contents == 0 && \
(info)->read_exec_only == 1 && \
(info)->seg_32bit == 0 && \
(info)->limit_in_pages == 0 && \
(info)->seg_not_present == 1 && \
(info)->useable == 0 )
#endif

69
include/asm-um/ldt.h
View File

@ -1,3 +1,72 @@
/*
* Copyright (C) 2004 Fujitsu Siemens Computers GmbH
* Licensed under the GPL
*
* Author: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
*/
#ifndef __ASM_LDT_I386_H
#define __ASM_LDT_I386_H
#include "asm/semaphore.h"
#include "asm/arch/ldt.h"
struct mmu_context_skas;
extern void ldt_host_info(void);
extern long init_new_ldt(struct mmu_context_skas * to_mm,
struct mmu_context_skas * from_mm);
extern void free_ldt(struct mmu_context_skas * mm);
#define LDT_PAGES_MAX \
((LDT_ENTRIES * LDT_ENTRY_SIZE)/PAGE_SIZE)
#define LDT_ENTRIES_PER_PAGE \
(PAGE_SIZE/LDT_ENTRY_SIZE)
#define LDT_DIRECT_ENTRIES \
((LDT_PAGES_MAX*sizeof(void *))/LDT_ENTRY_SIZE)
struct ldt_entry {
__u32 a;
__u32 b;
};
typedef struct uml_ldt {
int entry_count;
struct semaphore semaphore;
union {
struct ldt_entry * pages[LDT_PAGES_MAX];
struct ldt_entry entries[LDT_DIRECT_ENTRIES];
};
} uml_ldt_t;
/*
* macros stolen from include/asm-i386/desc.h
*/
#define LDT_entry_a(info) \
((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
#define LDT_entry_b(info) \
(((info)->base_addr & 0xff000000) | \
(((info)->base_addr & 0x00ff0000) >> 16) | \
((info)->limit & 0xf0000) | \
(((info)->read_exec_only ^ 1) << 9) | \
((info)->contents << 10) | \
(((info)->seg_not_present ^ 1) << 15) | \
((info)->seg_32bit << 22) | \
((info)->limit_in_pages << 23) | \
((info)->useable << 20) | \
0x7000)
#define LDT_empty(info) (\
(info)->base_addr == 0 && \
(info)->limit == 0 && \
(info)->contents == 0 && \
(info)->read_exec_only == 1 && \
(info)->seg_32bit == 0 && \
(info)->limit_in_pages == 0 && \
(info)->seg_not_present == 1 && \
(info)->useable == 0 )
#endif
#ifndef __UM_LDT_H
#define __UM_LDT_H