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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: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084307.333440475@linutronix.de
pull/1354/merge
Thomas Gleixner 2025-10-27 09:45:05 +01:00 committed by Ingo Molnar
parent c1cbad8f99
commit eaa9088d56
3 changed files with 18 additions and 3 deletions
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2
include/linux/entry-common.h
View File

@ -146,7 +146,7 @@ static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs)
local_irq_enable(); local_irq_enable();
} }
rseq_syscall(regs); rseq_debug_syscall_return(regs);
/* /*
* Do one-time syscall specific work. If these work items are * Do one-time syscall specific work. If these work items are

9
include/linux/rseq_entry.h
View File

@ -296,9 +296,18 @@ static __always_inline void rseq_exit_to_user_mode(void)
ev->events = 0; 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 */ #else /* CONFIG_RSEQ */
static inline void rseq_note_user_irq_entry(void) { } static inline void rseq_note_user_irq_entry(void) { }
static inline void rseq_exit_to_user_mode(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 /* !CONFIG_RSEQ */
#endif /* _LINUX_RSEQ_ENTRY_H */ #endif /* _LINUX_RSEQ_ENTRY_H */

10
kernel/rseq.c
View File

@ -473,12 +473,11 @@ error:
force_sigsegv(sig); force_sigsegv(sig);
} }
#ifdef CONFIG_DEBUG_RSEQ
/* /*
* Terminate the process if a syscall is issued within a restartable * Terminate the process if a syscall is issued within a restartable
* sequence. * sequence.
*/ */
void rseq_syscall(struct pt_regs *regs) void __rseq_debug_syscall_return(struct pt_regs *regs)
{ {
struct task_struct *t = current; struct task_struct *t = current;
u64 csaddr; u64 csaddr;
@ -496,6 +495,13 @@ void rseq_syscall(struct pt_regs *regs)
fail: fail:
force_sig(SIGSEGV); 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 #endif
/* /*