Skip to content

Commit

Permalink
x86: TLS cleanup
Browse files Browse the repository at this point in the history 
This consolidates the four different places that implemented the same
encoding magic for the GDT-slot 32-bit TLS support.  The old tls32.c was
renamed and is now only slightly modified to be the shared implementation.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
  • Loading branch information
Roland McGrath authored and Ingo Molnar committed Jan 30, 2008
1 parent 13abd0e commit efd1ca5
Show file tree
Hide file tree
Showing 9 changed files with 77 additions and 302 deletions.
4 changes: 2 additions & 2 deletions arch/x86/ia32/ia32entry.S
View file
Original file line number Diff line number Diff line change
Expand Up @@ -643,8 +643,8 @@ ia32_sys_call_table:
.quad compat_sys_futex /* 240 */
.quad compat_sys_sched_setaffinity
.quad compat_sys_sched_getaffinity
.quad sys32_set_thread_area
.quad sys32_get_thread_area
.quad sys_set_thread_area
.quad sys_get_thread_area
.quad compat_sys_io_setup /* 245 */
.quad sys_io_destroy
.quad compat_sys_io_getevents
Expand Down
1 change: 1 addition & 0 deletions arch/x86/kernel/Makefile_32
View file
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@ obj-y := process_32.o signal_32.o entry_32.o traps_32.o irq_32.o \
pci-dma_32.o i386_ksyms_32.o i387_32.o bootflag.o e820_32.o\
quirks.o i8237.o topology.o alternative.o i8253.o tsc_32.o io_delay.o rtc.o

obj-y += tls.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-y += cpu/
obj-y += acpi/
Expand Down
141 changes: 5 additions & 136 deletions arch/x86/kernel/process_32.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -501,32 +501,15 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long esp,
set_tsk_thread_flag(p, TIF_IO_BITMAP);
}

err = 0;

/*
* Set a new TLS for the child thread?
*/
if (clone_flags & CLONE_SETTLS) {
struct desc_struct *desc;
struct user_desc info;
int idx;

err = -EFAULT;
if (copy_from_user(&info, (void __user *)childregs->esi, sizeof(info)))
goto out;
err = -EINVAL;
if (LDT_empty(&info))
goto out;

idx = info.entry_number;
if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
goto out;

desc = p->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
desc->a = LDT_entry_a(&info);
desc->b = LDT_entry_b(&info);
}
if (clone_flags & CLONE_SETTLS)
err = do_set_thread_area(p, -1,
(struct user_desc __user *)childregs->esi, 0);

err = 0;
out:
if (err && p->thread.io_bitmap_ptr) {
kfree(p->thread.io_bitmap_ptr);
p->thread.io_bitmap_max = 0;
Expand Down Expand Up @@ -872,120 +855,6 @@ unsigned long get_wchan(struct task_struct *p)
return 0;
}

/*
* sys_alloc_thread_area: get a yet unused TLS descriptor index.
*/
static int get_free_idx(void)
{
struct thread_struct *t = &current->thread;
int idx;

for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++)
if (desc_empty(t->tls_array + idx))
return idx + GDT_ENTRY_TLS_MIN;
return -ESRCH;
}

/*
* Set a given TLS descriptor:
*/
asmlinkage int sys_set_thread_area(struct user_desc __user *u_info)
{
struct thread_struct *t = &current->thread;
struct user_desc info;
struct desc_struct *desc;
int cpu, idx;

if (copy_from_user(&info, u_info, sizeof(info)))
return -EFAULT;
idx = info.entry_number;

/*
* index -1 means the kernel should try to find and
* allocate an empty descriptor:
*/
if (idx == -1) {
idx = get_free_idx();
if (idx < 0)
return idx;
if (put_user(idx, &u_info->entry_number))
return -EFAULT;
}

if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
return -EINVAL;

desc = t->tls_array + idx - GDT_ENTRY_TLS_MIN;

/*
* We must not get preempted while modifying the TLS.
*/
cpu = get_cpu();

if (LDT_empty(&info)) {
desc->a = 0;
desc->b = 0;
} else {
desc->a = LDT_entry_a(&info);
desc->b = LDT_entry_b(&info);
}
load_TLS(t, cpu);

put_cpu();

return 0;
}

/*
* Get the current Thread-Local Storage area:
*/

#define GET_BASE(desc) ( \
(((desc)->a >> 16) & 0x0000ffff) | \
(((desc)->b << 16) & 0x00ff0000) | \
( (desc)->b & 0xff000000) )

#define GET_LIMIT(desc) ( \
((desc)->a & 0x0ffff) | \
((desc)->b & 0xf0000) )

#define GET_32BIT(desc) (((desc)->b >> 22) & 1)
#define GET_CONTENTS(desc) (((desc)->b >> 10) & 3)
#define GET_WRITABLE(desc) (((desc)->b >> 9) & 1)
#define GET_LIMIT_PAGES(desc) (((desc)->b >> 23) & 1)
#define GET_PRESENT(desc) (((desc)->b >> 15) & 1)
#define GET_USEABLE(desc) (((desc)->b >> 20) & 1)

asmlinkage int sys_get_thread_area(struct user_desc __user *u_info)
{
struct user_desc info;
struct desc_struct *desc;
int idx;

if (get_user(idx, &u_info->entry_number))
return -EFAULT;
if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
return -EINVAL;

memset(&info, 0, sizeof(info));

desc = current->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;

info.entry_number = idx;
info.base_addr = GET_BASE(desc);
info.limit = GET_LIMIT(desc);
info.seg_32bit = GET_32BIT(desc);
info.contents = GET_CONTENTS(desc);
info.read_exec_only = !GET_WRITABLE(desc);
info.limit_in_pages = GET_LIMIT_PAGES(desc);
info.seg_not_present = !GET_PRESENT(desc);
info.useable = GET_USEABLE(desc);

if (copy_to_user(u_info, &info, sizeof(info)))
return -EFAULT;
return 0;
}

unsigned long arch_align_stack(unsigned long sp)
{
if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
Expand Down
3 changes: 2 additions & 1 deletion arch/x86/kernel/process_64.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -524,7 +524,8 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long rsp,
if (clone_flags & CLONE_SETTLS) {
#ifdef CONFIG_IA32_EMULATION
if (test_thread_flag(TIF_IA32))
err = ia32_child_tls(p, childregs);
err = do_set_thread_area(p, -1,
(struct user_desc __user *)childregs->rsi, 0);
else
#endif
err = do_arch_prctl(p, ARCH_SET_FS, childregs->r8);
Expand Down
91 changes: 8 additions & 83 deletions arch/x86/kernel/ptrace_32.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -276,85 +276,6 @@ void ptrace_disable(struct task_struct *child)
clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
}

/*
* Perform get_thread_area on behalf of the traced child.
*/
static int
ptrace_get_thread_area(struct task_struct *child,
int idx, struct user_desc __user *user_desc)
{
struct user_desc info;
struct desc_struct *desc;

/*
* Get the current Thread-Local Storage area:
*/

#define GET_BASE(desc) ( \
(((desc)->a >> 16) & 0x0000ffff) | \
(((desc)->b << 16) & 0x00ff0000) | \
( (desc)->b & 0xff000000) )

#define GET_LIMIT(desc) ( \
((desc)->a & 0x0ffff) | \
((desc)->b & 0xf0000) )

#define GET_32BIT(desc) (((desc)->b >> 22) & 1)
#define GET_CONTENTS(desc) (((desc)->b >> 10) & 3)
#define GET_WRITABLE(desc) (((desc)->b >> 9) & 1)
#define GET_LIMIT_PAGES(desc) (((desc)->b >> 23) & 1)
#define GET_PRESENT(desc) (((desc)->b >> 15) & 1)
#define GET_USEABLE(desc) (((desc)->b >> 20) & 1)

if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
return -EINVAL;

desc = child->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;

info.entry_number = idx;
info.base_addr = GET_BASE(desc);
info.limit = GET_LIMIT(desc);
info.seg_32bit = GET_32BIT(desc);
info.contents = GET_CONTENTS(desc);
info.read_exec_only = !GET_WRITABLE(desc);
info.limit_in_pages = GET_LIMIT_PAGES(desc);
info.seg_not_present = !GET_PRESENT(desc);
info.useable = GET_USEABLE(desc);

if (copy_to_user(user_desc, &info, sizeof(info)))
return -EFAULT;

return 0;
}

/*
* Perform set_thread_area on behalf of the traced child.
*/
static int
ptrace_set_thread_area(struct task_struct *child,
int idx, struct user_desc __user *user_desc)
{
struct user_desc info;
struct desc_struct *desc;

if (copy_from_user(&info, user_desc, sizeof(info)))
return -EFAULT;

if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
return -EINVAL;

desc = child->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
if (LDT_empty(&info)) {
desc->a = 0;
desc->b = 0;
} else {
desc->a = LDT_entry_a(&info);
desc->b = LDT_entry_b(&info);
}

return 0;
}

long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
struct user * dummy = NULL;
Expand Down Expand Up @@ -601,13 +522,17 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
}

case PTRACE_GET_THREAD_AREA:
ret = ptrace_get_thread_area(child, addr,
(struct user_desc __user *) data);
if (addr < 0)
return -EIO;
ret = do_get_thread_area(child, addr,
(struct user_desc __user *) data);
break;

case PTRACE_SET_THREAD_AREA:
ret = ptrace_set_thread_area(child, addr,
(struct user_desc __user *) data);
if (addr < 0)
return -EIO;
ret = do_set_thread_area(child, addr,
(struct user_desc __user *) data, 0);
break;

default:
Expand Down
26 changes: 11 additions & 15 deletions arch/x86/kernel/ptrace_64.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -474,23 +474,19 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
64bit debugger to fully examine them too. Better
don't use it against 64bit processes, use
PTRACE_ARCH_PRCTL instead. */
case PTRACE_SET_THREAD_AREA: {
struct user_desc __user *p;
int old;
p = (struct user_desc __user *)data;
get_user(old, &p->entry_number);
put_user(addr, &p->entry_number);
ret = do_set_thread_area(&child->thread, p);
put_user(old, &p->entry_number);
break;
case PTRACE_GET_THREAD_AREA:
p = (struct user_desc __user *)data;
get_user(old, &p->entry_number);
put_user(addr, &p->entry_number);
ret = do_get_thread_area(&child->thread, p);
put_user(old, &p->entry_number);
if (addr < 0)
return -EIO;
ret = do_get_thread_area(child, addr,
(struct user_desc __user *) data);

break;
case PTRACE_SET_THREAD_AREA:
if (addr < 0)
return -EIO;
ret = do_set_thread_area(child, addr,
(struct user_desc __user *) data, 0);
break;
}
#endif
/* normal 64bit interface to access TLS data.
Works just like arch_prctl, except that the arguments
Expand Down
Loading

0 comments on commit efd1ca5

Please sign in to comment.