Commit 96e2fbcc authored by Sven Schnelle's avatar Sven Schnelle Committed by Thomas Gleixner
Browse files

entry_Add_enter_from_user_mode_wrapper 



To be called from architecture specific code if the combo interfaces are
not suitable. It simply calls __enter_from_user_mode(). This way
__enter_from_user_mode will still be inlined because it is declared static
__always_inline.

[ tglx: Amend comments and move it to a different location in the header ]

Signed-off-by: default avatarSven Schnelle <svens@linux.ibm.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201201142755.31931-4-svens@linux.ibm.com
parent bb793562

include/linux/entry-common.h

+23 −1
Original line number Diff line number Diff line
@@ -101,6 +101,27 @@ static inline __must_check int arch_syscall_enter_tracehook(struct pt_regs *regs 
}

#endif



/**

 * enter_from_user_mode - Establish state when coming from user mode

 *

 * Syscall/interrupt entry disables interrupts, but user mode is traced as

 * interrupts enabled. Also with NO_HZ_FULL RCU might be idle.

 *

 * 1) Tell lockdep that interrupts are disabled

 * 2) Invoke context tracking if enabled to reactivate RCU

 * 3) Trace interrupts off state

 *

 * Invoked from architecture specific syscall entry code with interrupts

 * disabled. The calling code has to be non-instrumentable. When the

 * function returns all state is correct and interrupts are still

 * disabled. The subsequent functions can be instrumented.

 *

 * This is invoked when there is architecture specific functionality to be

 * done between establishing state and enabling interrupts. The caller must

 * enable interrupts before invoking syscall_enter_from_user_mode_work().

 */

void enter_from_user_mode(struct pt_regs *regs);



/**

 * syscall_enter_from_user_mode_prepare - Establish state and enable interrupts

 * @regs:	Pointer to currents pt_regs
@@ -110,7 +131,8 @@ static inline __must_check int arch_syscall_enter_tracehook(struct pt_regs *regs 
 * function returns all state is correct, interrupts are enabled and the

 * subsequent functions can be instrumented.

 *

 * This handles lockdep, RCU (context tracking) and tracing state.

 * This handles lockdep, RCU (context tracking) and tracing state, i.e.

 * the functionality provided by enter_from_user_mode().

 *

 * This is invoked when there is extra architecture specific functionality

 * to be done between establishing state and handling user mode entry work.

kernel/entry/common.c

+6 −10
Original line number Diff line number Diff line
@@ -10,16 +10,7 @@ 
#define CREATE_TRACE_POINTS

#include <trace/events/syscalls.h>



/**

 * __enter_from_user_mode - Establish state when coming from user mode

 *

 * Syscall/interrupt entry disables interrupts, but user mode is traced as

 * interrupts enabled. Also with NO_HZ_FULL RCU might be idle.

 *

 * 1) Tell lockdep that interrupts are disabled

 * 2) Invoke context tracking if enabled to reactivate RCU

 * 3) Trace interrupts off state

 */

/* See comment for enter_from_user_mode() in entry-common.h */

static __always_inline void __enter_from_user_mode(struct pt_regs *regs)

{

	arch_check_user_regs(regs);
@@ -33,6 +24,11 @@ static __always_inline void __enter_from_user_mode(struct pt_regs *regs) 
	instrumentation_end();

}



void noinstr enter_from_user_mode(struct pt_regs *regs)

{

	__enter_from_user_mode(regs);

}



static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)

{

	if (unlikely(audit_context())) {