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x86: get rid of TIF_IRET hackery 

TIF_NOTIFY_RESUME will work in precisely the same way; all that
is achieved by TIF_IRET is appearing that there's some work to be
done, so we end up on the iret exit path.  Just use NOTIFY_RESUME.
And for execve() do that in 32bit start_thread(), not sys_execve()
itself.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-08-02 22:12:06 +04:00
parent c46de2263f
commit e76623d694
5 changed files with 8 additions and 17 deletions
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2
arch/x86/include/asm/thread_info.h
View File

@ -79,7 +79,6 @@ struct thread_info {
#define TIF_SIGPENDING 2 /* signal pending */ #define TIF_SIGPENDING 2 /* signal pending */
#define TIF_NEED_RESCHED 3 /* rescheduling necessary */ #define TIF_NEED_RESCHED 3 /* rescheduling necessary */
#define TIF_SINGLESTEP 4 /* reenable singlestep on user return*/ #define TIF_SINGLESTEP 4 /* reenable singlestep on user return*/
#define TIF_IRET 5 /* force IRET */
#define TIF_SYSCALL_EMU 6 /* syscall emulation active */ #define TIF_SYSCALL_EMU 6 /* syscall emulation active */
#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */ #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
#define TIF_SECCOMP 8 /* secure computing */ #define TIF_SECCOMP 8 /* secure computing */
@ -104,7 +103,6 @@ struct thread_info {
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING) #define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP) #define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
#define _TIF_IRET (1 << TIF_IRET)
#define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU) #define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP (1 << TIF_SECCOMP) #define _TIF_SECCOMP (1 << TIF_SECCOMP)

8
arch/x86/kernel/process.c
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@ -351,14 +351,6 @@ long sys_execve(const char __user *name,
if (IS_ERR(filename)) if (IS_ERR(filename))
return error; return error;
error = do_execve(filename, argv, envp, regs); error = do_execve(filename, argv, envp, regs);
#ifdef CONFIG_X86_32
if (error == 0) {
/* Make sure we don't return using sysenter.. */
set_thread_flag(TIF_IRET);
}
#endif
putname(filename); putname(filename);
return error; return error;
} }

5
arch/x86/kernel/process_32.c
View File

@ -194,6 +194,11 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
* Free the old FP and other extended state * Free the old FP and other extended state
*/ */
free_thread_xstate(current); free_thread_xstate(current);
/*
* force it to the iret return path by making it look as if there was
* some work pending.
*/
set_thread_flag(TIF_NOTIFY_RESUME);
} }
EXPORT_SYMBOL_GPL(start_thread); EXPORT_SYMBOL_GPL(start_thread);

4
arch/x86/kernel/signal.c
View File

@ -800,10 +800,6 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
} }
if (thread_info_flags & _TIF_USER_RETURN_NOTIFY) if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
fire_user_return_notifiers(); fire_user_return_notifiers();
#ifdef CONFIG_X86_32
clear_thread_flag(TIF_IRET);
#endif /* CONFIG_X86_32 */
} }
void signal_fault(struct pt_regs *regs, void __user *frame, char *where) void signal_fault(struct pt_regs *regs, void __user *frame, char *where)

6
arch/x86/kernel/vm86_32.c
View File

@ -561,9 +561,9 @@ int handle_vm86_trap(struct kernel_vm86_regs *regs, long error_code, int trapno)
if ((trapno == 3) || (trapno == 1)) { if ((trapno == 3) || (trapno == 1)) {
KVM86->regs32->ax = VM86_TRAP + (trapno << 8); KVM86->regs32->ax = VM86_TRAP + (trapno << 8);
/* setting this flag forces the code in entry_32.S to /* setting this flag forces the code in entry_32.S to
call save_v86_state() and change the stack pointer the path where we call save_v86_state() and change
to KVM86->regs32 */ the stack pointer to KVM86->regs32 */
set_thread_flag(TIF_IRET); set_thread_flag(TIF_NOTIFY_RESUME);
return 0; return 0;
} }
do_int(regs, trapno, (unsigned char __user *) (regs->pt.ss << 4), SP(regs)); do_int(regs, trapno, (unsigned char __user *) (regs->pt.ss << 4), SP(regs));