Commit eaa9088d authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

rseq: Use static branch for syscall exit debug when GENERIC_IRQ_ENTRY=y 



Make the syscall exit debug mechanism available via the static branch on
architectures which utilize the generic entry code.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Reviewed-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084307.333440475@linutronix.de
parent c1cbad8f

include/linux/entry-common.h

+1 −1
Original line number Diff line number Diff line
@@ -146,7 +146,7 @@ static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs) 
			local_irq_enable();

	}



	rseq_syscall(regs);

	rseq_debug_syscall_return(regs);



	/*

	 * Do one-time syscall specific work. If these work items are

include/linux/rseq_entry.h

+9 −0
Original line number Diff line number Diff line
@@ -296,9 +296,18 @@ static __always_inline void rseq_exit_to_user_mode(void) 
	ev->events = 0;

}



void __rseq_debug_syscall_return(struct pt_regs *regs);



static inline void rseq_debug_syscall_return(struct pt_regs *regs)

{

	if (static_branch_unlikely(&rseq_debug_enabled))

		__rseq_debug_syscall_return(regs);

}



#else /* CONFIG_RSEQ */

static inline void rseq_note_user_irq_entry(void) { }

static inline void rseq_exit_to_user_mode(void) { }

static inline void rseq_debug_syscall_return(struct pt_regs *regs) { }

#endif /* !CONFIG_RSEQ */



#endif /* _LINUX_RSEQ_ENTRY_H */

kernel/rseq.c

+8 −2
Original line number Diff line number Diff line
@@ -473,12 +473,11 @@ void __rseq_handle_notify_resume(struct ksignal *ksig, struct pt_regs *regs) 
	force_sigsegv(sig);

}



#ifdef CONFIG_DEBUG_RSEQ

/*

 * Terminate the process if a syscall is issued within a restartable

 * sequence.

 */

void rseq_syscall(struct pt_regs *regs)

void __rseq_debug_syscall_return(struct pt_regs *regs)

{

	struct task_struct *t = current;

	u64 csaddr;
@@ -496,6 +495,13 @@ void rseq_syscall(struct pt_regs *regs) 
fail:

	force_sig(SIGSEGV);

}



#ifdef CONFIG_DEBUG_RSEQ

/* Kept around to keep GENERIC_ENTRY=n architectures supported. */

void rseq_syscall(struct pt_regs *regs)

{

	__rseq_debug_syscall_return(regs);

}

#endif



/*