Commit e1647100 authored by Jinjie Ruan's avatar Jinjie Ruan Committed by Thomas Gleixner
Browse files

entry: Rework syscall_exit_to_user_mode_work() for architecture reuse 



syscall_exit_to_user_mode_work() invokes local_irq_disable_exit_to_user()
and syscall_exit_to_user_mode_prepare() after handling pending syscall exit
work.

The conversion of ARM64 to the generic entry code requires this to be split
up, so move the invocations of local_irq_disable_exit_to_user() and
syscall_exit_to_user_mode_prepare() into the only caller.

No functional change intended.

[ tglx: Massaged changelog and comments ]

Signed-off-by: default avatarJinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: default avatarThomas Gleixner <tglx@kernel.org>
Reviewed-by: default avatarKevin Brodsky <kevin.brodsky@arm.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20260128031934.3906955-10-ruanjinjie@huawei.com
parent 03150a9f

include/linux/entry-common.h

+11 −14
Original line number Diff line number Diff line
@@ -122,17 +122,12 @@ static __always_inline long syscall_enter_from_user_mode(struct pt_regs *regs, l 
void syscall_exit_work(struct pt_regs *regs, unsigned long work);



/**

 * syscall_exit_to_user_mode_work - Handle work before returning to user mode

 * syscall_exit_to_user_mode_work - Handle one time work before returning to user mode

 * @regs:	Pointer to currents pt_regs

 *

 * Same as step 1 and 2 of syscall_exit_to_user_mode() but without calling

 * exit_to_user_mode() to perform the final transition to user mode.

 * Step 1 of syscall_exit_to_user_mode() with the same calling convention.

 *

 * Calling convention is the same as for syscall_exit_to_user_mode() and it

 * returns with all work handled and interrupts disabled. The caller must

 * invoke exit_to_user_mode() before actually switching to user mode to

 * make the final state transitions. Interrupts must stay disabled between

 * return from this function and the invocation of exit_to_user_mode().

 * The caller must invoke steps 2-3 of syscall_exit_to_user_mode() afterwards.

 */

static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs)

{
@@ -155,15 +150,13 @@ static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs) 
	 */

	if (unlikely(work & SYSCALL_WORK_EXIT))

		syscall_exit_work(regs, work);

	local_irq_disable_exit_to_user();

	syscall_exit_to_user_mode_prepare(regs);

}



/**

 * syscall_exit_to_user_mode - Handle work before returning to user mode

 * @regs:	Pointer to currents pt_regs

 *

 * Invoked with interrupts enabled and fully valid regs. Returns with all

 * Invoked with interrupts enabled and fully valid @regs. Returns with all

 * work handled, interrupts disabled such that the caller can immediately

 * switch to user mode. Called from architecture specific syscall and ret

 * from fork code.
@@ -176,6 +169,7 @@ static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs) 
 *	- ptrace (single stepping)

 *

 *  2) Preparatory work

 *	- Disable interrupts

 *	- Exit to user mode loop (common TIF handling). Invokes

 *	  arch_exit_to_user_mode_work() for architecture specific TIF work

 *	- Architecture specific one time work arch_exit_to_user_mode_prepare()
@@ -184,14 +178,17 @@ static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs) 
 *  3) Final transition (lockdep, tracing, context tracking, RCU), i.e. the

 *     functionality in exit_to_user_mode().

 *

 * This is a combination of syscall_exit_to_user_mode_work() (1,2) and

 * exit_to_user_mode(). This function is preferred unless there is a

 * compelling architectural reason to use the separate functions.

 * This is a combination of syscall_exit_to_user_mode_work() (1), disabling

 * interrupts followed by syscall_exit_to_user_mode_prepare() (2) and

 * exit_to_user_mode() (3). This function is preferred unless there is a

 * compelling architectural reason to invoke the functions separately.

 */

static __always_inline void syscall_exit_to_user_mode(struct pt_regs *regs)

{

	instrumentation_begin();

	syscall_exit_to_user_mode_work(regs);

	local_irq_disable_exit_to_user();

	syscall_exit_to_user_mode_prepare(regs);

	instrumentation_end();

	exit_to_user_mode();

}