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Commit b9d989c7 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
Browse files

x86/asm: Move the thread_info::status field to thread_struct 



Because sched.h and thread_info.h are a tangled mess, I turned
in_compat_syscall() into a macro.  If we had current_thread_struct()
or similar and we could use it from thread_info.h, then this would
be a bit cleaner.

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jann Horn <jann@thejh.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/ccc8a1b2f41f9c264a41f771bb4a6539a642ad72.1473801993.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent d4b80afb

arch/x86/entry/common.c

+2 −2
Original line number Diff line number Diff line
@@ -209,7 +209,7 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs) 
	 * special case only applies after poking regs and before the

	 * very next return to user mode.

	 */

	ti->status &= ~(TS_COMPAT|TS_I386_REGS_POKED);

	current->thread.status &= ~(TS_COMPAT|TS_I386_REGS_POKED);

#endif



	user_enter_irqoff();
@@ -307,7 +307,7 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs) 
	unsigned int nr = (unsigned int)regs->orig_ax;



#ifdef CONFIG_IA32_EMULATION

	ti->status |= TS_COMPAT;

	current->thread.status |= TS_COMPAT;

#endif



	if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) {

arch/x86/include/asm/processor.h

+12 −0
Original line number Diff line number Diff line
@@ -389,6 +389,9 @@ struct thread_struct { 
	unsigned short		fsindex;

	unsigned short		gsindex;

#endif



	u32			status;		/* thread synchronous flags */



#ifdef CONFIG_X86_64

	unsigned long		fsbase;

	unsigned long		gsbase;
@@ -434,6 +437,15 @@ struct thread_struct { 
	 */

};



/*

 * Thread-synchronous status.

 *

 * This is different from the flags in that nobody else

 * ever touches our thread-synchronous status, so we don't

 * have to worry about atomic accesses.

 */

#define TS_COMPAT		0x0002	/* 32bit syscall active (64BIT)*/



/*

 * Set IOPL bits in EFLAGS from given mask

 */

arch/x86/include/asm/syscall.h

+5 −15
Original line number Diff line number Diff line
@@ -60,7 +60,7 @@ static inline long syscall_get_error(struct task_struct *task, 
	 * TS_COMPAT is set for 32-bit syscall entries and then

	 * remains set until we return to user mode.

	 */

	if (task_thread_info(task)->status & (TS_COMPAT|TS_I386_REGS_POKED))

	if (task->thread.status & (TS_COMPAT|TS_I386_REGS_POKED))

		/*

		 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO

		 * and will match correctly in comparisons.
@@ -116,7 +116,7 @@ static inline void syscall_get_arguments(struct task_struct *task, 
					 unsigned long *args)

{

# ifdef CONFIG_IA32_EMULATION

	if (task_thread_info(task)->status & TS_COMPAT)

	if (task->thread.status & TS_COMPAT)

		switch (i) {

		case 0:

			if (!n--) break;
@@ -177,7 +177,7 @@ static inline void syscall_set_arguments(struct task_struct *task, 
					 const unsigned long *args)

{

# ifdef CONFIG_IA32_EMULATION

	if (task_thread_info(task)->status & TS_COMPAT)

	if (task->thread.status & TS_COMPAT)

		switch (i) {

		case 0:

			if (!n--) break;
@@ -234,18 +234,8 @@ static inline void syscall_set_arguments(struct task_struct *task, 


static inline int syscall_get_arch(void)

{

#ifdef CONFIG_IA32_EMULATION

	/*

	 * TS_COMPAT is set for 32-bit syscall entry and then

	 * remains set until we return to user mode.

	 *

	 * x32 tasks should be considered AUDIT_ARCH_X86_64.

	 */

	if (task_thread_info(current)->status & TS_COMPAT)

		return AUDIT_ARCH_I386;

#endif

	/* Both x32 and x86_64 are considered "64-bit". */

	return AUDIT_ARCH_X86_64;

	/* x32 tasks should be considered AUDIT_ARCH_X86_64. */

	return in_ia32_syscall() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;

}

#endif	/* CONFIG_X86_32 */

arch/x86/include/asm/thread_info.h

+4 −19
Original line number Diff line number Diff line
@@ -55,7 +55,6 @@ struct task_struct; 
struct thread_info {

	struct task_struct	*task;		/* main task structure */

	__u32			flags;		/* low level flags */

	__u32			status;		/* thread synchronous flags */

	__u32			cpu;		/* current CPU */

};
@@ -253,31 +252,17 @@ static inline int arch_within_stack_frames(const void * const stack, 


#endif



/*

 * Thread-synchronous status.

 *

 * This is different from the flags in that nobody else

 * ever touches our thread-synchronous status, so we don't

 * have to worry about atomic accesses.

 */

#define TS_COMPAT		0x0002	/* 32bit syscall active (64BIT)*/

#ifdef CONFIG_COMPAT

#define TS_I386_REGS_POKED	0x0004	/* regs poked by 32-bit ptracer */

#endif



#ifndef __ASSEMBLY__



static inline bool in_ia32_syscall(void)

{

#ifdef CONFIG_X86_32

	return true;

#endif

#ifdef CONFIG_IA32_EMULATION

	if (current_thread_info()->status & TS_COMPAT)

		return true;

#define in_ia32_syscall() true

#else

#define in_ia32_syscall() (IS_ENABLED(CONFIG_IA32_EMULATION) && \

			   current->thread.status & TS_COMPAT)

#endif

	return false;

}



/*

 * Force syscall return via IRET by making it look as if there was

arch/x86/kernel/asm-offsets.c

+0 −1
Original line number Diff line number Diff line
@@ -36,7 +36,6 @@ void common(void) { 


	BLANK();

	OFFSET(TI_flags, thread_info, flags);

	OFFSET(TI_status, thread_info, status);



	BLANK();

	OFFSET(TASK_addr_limit, task_struct, thread.addr_limit);