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Subject[77/89] x86: get rid of the insane TIF_ABI_PENDING bit
2.6.31-stable review patch.  If anyone has any objections, please let us know.

------------------

From: H. Peter Anvin <hpa@zytor.com>

commit 05d43ed8a89c159ff641d472f970e3f1baa66318 upstream.

Now that the previous commit made it possible to do the personality
setting at the point of no return, we do just that for ELF binaries.
And suddenly all the reasons for that insane TIF_ABI_PENDING bit go
away, and we can just make SET_PERSONALITY() just do the obvious thing
for a 32-bit compat process.

Everything becomes much more straightforward this way.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

---
arch/x86/ia32/ia32_aout.c | 1 -
arch/x86/include/asm/elf.h | 10 ++--------
arch/x86/include/asm/thread_info.h | 2 --
arch/x86/kernel/process.c | 12 ------------
arch/x86/kernel/process_64.c | 11 +++++++++++
5 files changed, 13 insertions(+), 23 deletions(-)

--- a/arch/x86/ia32/ia32_aout.c
+++ b/arch/x86/ia32/ia32_aout.c
@@ -311,7 +311,6 @@ static int load_aout_binary(struct linux
/* OK, This is the point of no return */
set_personality(PER_LINUX);
set_thread_flag(TIF_IA32);
- clear_thread_flag(TIF_ABI_PENDING);

setup_new_exec(bprm);

--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -197,14 +197,8 @@ do { \
set_fs(USER_DS); \
} while (0)

-#define COMPAT_SET_PERSONALITY(ex) \
-do { \
- if (test_thread_flag(TIF_IA32)) \
- clear_thread_flag(TIF_ABI_PENDING); \
- else \
- set_thread_flag(TIF_ABI_PENDING); \
- current->personality |= force_personality32; \
-} while (0)
+void set_personality_ia32(void);
+#define COMPAT_SET_PERSONALITY(ex) set_personality_ia32()

#define COMPAT_ELF_PLATFORM ("i686")

--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -86,7 +86,6 @@ struct thread_info {
#define TIF_NOTSC 16 /* TSC is not accessible in userland */
#define TIF_IA32 17 /* 32bit process */
#define TIF_FORK 18 /* ret_from_fork */
-#define TIF_ABI_PENDING 19
#define TIF_MEMDIE 20
#define TIF_DEBUG 21 /* uses debug registers */
#define TIF_IO_BITMAP 22 /* uses I/O bitmap */
@@ -110,7 +109,6 @@ struct thread_info {
#define _TIF_NOTSC (1 << TIF_NOTSC)
#define _TIF_IA32 (1 << TIF_IA32)
#define _TIF_FORK (1 << TIF_FORK)
-#define _TIF_ABI_PENDING (1 << TIF_ABI_PENDING)
#define _TIF_DEBUG (1 << TIF_DEBUG)
#define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP)
#define _TIF_FREEZE (1 << TIF_FREEZE)
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -94,18 +94,6 @@ void flush_thread(void)
{
struct task_struct *tsk = current;

-#ifdef CONFIG_X86_64
- if (test_tsk_thread_flag(tsk, TIF_ABI_PENDING)) {
- clear_tsk_thread_flag(tsk, TIF_ABI_PENDING);
- if (test_tsk_thread_flag(tsk, TIF_IA32)) {
- clear_tsk_thread_flag(tsk, TIF_IA32);
- } else {
- set_tsk_thread_flag(tsk, TIF_IA32);
- current_thread_info()->status |= TS_COMPAT;
- }
- }
-#endif
-
clear_tsk_thread_flag(tsk, TIF_DEBUG);

tsk->thread.debugreg0 = 0;
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -534,6 +534,17 @@ sys_clone(unsigned long clone_flags, uns
return do_fork(clone_flags, newsp, regs, 0, parent_tid, child_tid);
}

+void set_personality_ia32(void)
+{
+ /* inherit personality from parent */
+
+ /* Make sure to be in 32bit mode */
+ set_thread_flag(TIF_IA32);
+
+ /* Prepare the first "return" to user space */
+ current_thread_info()->status |= TS_COMPAT;
+}
+
unsigned long get_wchan(struct task_struct *p)
{
unsigned long stack;



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