Commit 29915524 authored by Gabriel Krisman Bertazi's avatar Gabriel Krisman Bertazi Committed by Thomas Gleixner
Browse files

entry: Drop usage of TIF flags in the generic syscall code 



Now that the flags migration in the common syscall entry code is complete
and the code relies exclusively on thread_info::syscall_work, clean up the
accesses to TI flags in that path.

Signed-off-by: default avatarGabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarAndy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20201116174206.2639648-10-krisman@collabora.com
parent 785dc4eb

include/linux/entry-common.h

+12 −14
Original line number Diff line number Diff line
@@ -26,31 +26,29 @@ 
#endif



/*

 * TIF flags handled in syscall_enter_from_user_mode()

 * SYSCALL_WORK flags handled in syscall_enter_from_user_mode()

 */

#ifndef ARCH_SYSCALL_ENTER_WORK

# define ARCH_SYSCALL_ENTER_WORK	(0)

#ifndef ARCH_SYSCALL_WORK_ENTER

# define ARCH_SYSCALL_WORK_ENTER	(0)

#endif



#define SYSCALL_ENTER_WORK ARCH_SYSCALL_ENTER_WORK



/*

 * TIF flags handled in syscall_exit_to_user_mode()

 * SYSCALL_WORK flags handled in syscall_exit_to_user_mode()

 */

#ifndef ARCH_SYSCALL_EXIT_WORK

# define ARCH_SYSCALL_EXIT_WORK		(0)

#ifndef ARCH_SYSCALL_WORK_EXIT

# define ARCH_SYSCALL_WORK_EXIT		(0)

#endif



#define SYSCALL_EXIT_WORK ARCH_SYSCALL_EXIT_WORK



#define SYSCALL_WORK_ENTER	(SYSCALL_WORK_SECCOMP |			\

				 SYSCALL_WORK_SYSCALL_TRACEPOINT |	\

				 SYSCALL_WORK_SYSCALL_TRACE |		\

				 SYSCALL_WORK_SYSCALL_EMU |		\

				 SYSCALL_WORK_SYSCALL_AUDIT)

				 SYSCALL_WORK_SYSCALL_AUDIT |		\

				 ARCH_SYSCALL_WORK_ENTER)

#define SYSCALL_WORK_EXIT	(SYSCALL_WORK_SYSCALL_TRACEPOINT |	\

				 SYSCALL_WORK_SYSCALL_TRACE |		\

				 SYSCALL_WORK_SYSCALL_AUDIT)

				 SYSCALL_WORK_SYSCALL_AUDIT |		\

				 ARCH_SYSCALL_WORK_EXIT)



/*

 * TIF flags handled in exit_to_user_mode_loop()
@@ -136,8 +134,8 @@ void syscall_enter_from_user_mode_prepare(struct pt_regs *regs); 
 *

 * It handles the following work items:

 *

 *  1) TIF flag dependent invocations of arch_syscall_enter_tracehook(),

 *     __secure_computing(), trace_sys_enter()

 *  1) syscall_work flag dependent invocations of

 *     arch_syscall_enter_tracehook(), __secure_computing(), trace_sys_enter()

 *  2) Invocation of audit_syscall_entry()

 */

long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall);

kernel/entry/common.c

+7 −10
Original line number Diff line number Diff line
@@ -42,7 +42,7 @@ static inline void syscall_enter_audit(struct pt_regs *regs, long syscall) 
}



static long syscall_trace_enter(struct pt_regs *regs, long syscall,

				unsigned long ti_work, unsigned long work)

				unsigned long work)

{

	long ret = 0;
@@ -75,11 +75,9 @@ static __always_inline long 
__syscall_enter_from_user_work(struct pt_regs *regs, long syscall)

{

	unsigned long work = READ_ONCE(current_thread_info()->syscall_work);

	unsigned long ti_work;



	ti_work = READ_ONCE(current_thread_info()->flags);

	if (work & SYSCALL_WORK_ENTER || ti_work & SYSCALL_ENTER_WORK)

		syscall = syscall_trace_enter(regs, syscall, ti_work, work);

	if (work & SYSCALL_WORK_ENTER)

		syscall = syscall_trace_enter(regs, syscall, work);



	return syscall;

}
@@ -227,8 +225,8 @@ static inline bool report_single_step(unsigned long work) 
}

#endif



static void syscall_exit_work(struct pt_regs *regs, unsigned long ti_work,

			      unsigned long work)



static void syscall_exit_work(struct pt_regs *regs, unsigned long work)

{

	bool step;
@@ -249,7 +247,6 @@ static void syscall_exit_work(struct pt_regs *regs, unsigned long ti_work, 
static void syscall_exit_to_user_mode_prepare(struct pt_regs *regs)

{

	unsigned long work = READ_ONCE(current_thread_info()->syscall_work);

	u32 cached_flags = READ_ONCE(current_thread_info()->flags);

	unsigned long nr = syscall_get_nr(current, regs);



	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
@@ -266,8 +263,8 @@ static void syscall_exit_to_user_mode_prepare(struct pt_regs *regs) 
	 * enabled, we want to run them exactly once per syscall exit with

	 * interrupts enabled.

	 */

	if (unlikely(work & SYSCALL_WORK_EXIT || cached_flags & SYSCALL_EXIT_WORK))

		syscall_exit_work(regs, cached_flags, work);

	if (unlikely(work & SYSCALL_WORK_EXIT))

		syscall_exit_work(regs, work);

}



__visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs)