From nobody Fri Oct 3 23:08:26 2025 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9F1F82F0C50 for ; Sat, 23 Aug 2025 16:40:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755967206; cv=none; b=a5OXhnsi7dY9eU04aopEGSSDvig6RJJig60iQNQLQmnXLNCNwqHzhVssHVFjqoZ53fKfCePd2SxVfg/b3riZv/iPAoXoRwCHvs+ajloMYeceGctoxl+IIVVIoM+9J1touLygWGSuCS99v/kd4P+I/ZQEpljToUoGuVbHtlsRBNA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755967206; c=relaxed/simple; bh=aHyYhrngWqwek+zL2LXHM/m7IygoiX4dvSyBLnV+pro=; h=Message-ID:From:To:Cc:Subject:References:MIME-Version: Content-Type:Date; b=lXBmVYaufN+Otzy2SZMc1StPNq+7kc/ZXnlDXGaB9rU4QSxgpkFGoAEeNV7np4UGvvEs70XoqGh70c7IkHp7REk80QLjdmWhOt9ofHEew7CxiuiIoifZGnYMrZZDMYlVXwY0UVIX53to4K1CeD3OBhu9w+PD2r/re3oRqZi1L0U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=JlVmszf6; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=BH9vQR+Q; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="JlVmszf6"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="BH9vQR+Q" Message-ID: <20250823161654.677961303@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1755967202; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=w6iXRrtymKNRLhlRnwTuItMwaWaIGSiBnDPpk0Weh9Q=; b=JlVmszf6zuLa558wwGwXfsGer34qAWJgk4Io4gI4Hi7UQHBaySGe7ETrrzvPeD3tV22SOw 9aQMn7iLlyTBMzB4t9Wl+WiW8XrLAQmNBx/8jkygSYHpbs2xwdfC16/QLAEPzQA/0xPTUO QG9tUVGpIv3nDqo1BKJz0ytFoHZ0IonotzgD2KbtiLjs1SH0Yw1XsZUj1KQ/xia5j0tmGu sQkKs9MDeOO3NRfmWeAdfKAL1pnxkHv+aFyKCXV5xRneybb1T574STRPspaxx/+aME59lt KxpQzSk1Ddri4SGXC+cjnDlcgNp3NTZg9eaNRlJOQo4CorE/U6JoDTseFOYHfw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1755967202; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=w6iXRrtymKNRLhlRnwTuItMwaWaIGSiBnDPpk0Weh9Q=; b=BH9vQR+Qa4g0mmwNxUL2Axhqar7ElTUzcJmwtQoKv5dlRRO9dq4RqjAhCJzqKh+khhjw1V tblihcYN0GmnkGDw== From: Thomas Gleixner To: LKML Cc: Jens Axboe , Mathieu Desnoyers , Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , Paolo Bonzini , Sean Christopherson , Wei Liu , Dexuan Cui , x86@kernel.org, Arnd Bergmann , Heiko Carstens , Christian Borntraeger , Sven Schnelle , Huacai Chen , Paul Walmsley , Palmer Dabbelt Subject: [patch V2 22/37] rseq: Use static branch for syscall exit debug when GENERIC_IRQ_ENTRY=y References: <20250823161326.635281786@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Sat, 23 Aug 2025 18:40:01 +0200 (CEST) Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Make the syscall exit debug mechanism available via the static branch on architectures which utilize the generic entry code. Signed-off-by: Thomas Gleixner Reviewed-by: Mathieu Desnoyers --- include/linux/entry-common.h | 2 +- include/linux/rseq_entry.h | 9 +++++++++ kernel/rseq.c | 19 +++++++++++++------ 3 files changed, 23 insertions(+), 7 deletions(-) --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -146,7 +146,7 @@ static __always_inline void syscall_exit local_irq_enable(); } =20 - rseq_syscall(regs); + rseq_debug_syscall_return(regs); =20 /* * Do one-time syscall specific work. If these work items are --- a/include/linux/rseq_entry.h +++ b/include/linux/rseq_entry.h @@ -286,9 +286,18 @@ static __always_inline void rseq_exit_to ev->events =3D 0; } =20 +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 */ =20 #endif /* _LINUX_RSEQ_ENTRY_H */ --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -470,12 +470,7 @@ void __rseq_handle_notify_resume(struct force_sigsegv(sig); } =20 -#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 =3D current; u64 csaddr; @@ -493,6 +488,18 @@ void rseq_syscall(struct pt_regs *regs) fail: force_sig(SIGSEGV); } + +#ifdef CONFIG_DEBUG_RSEQ +/* + * Kept around to keep GENERIC_ENTRY=3Dn architectures supported. + * + * Terminate the process if a syscall is issued within a restartable + * sequence. + */ +void rseq_syscall(struct pt_regs *regs) +{ + __rseq_debug_syscall_return(regs); +} #endif =20 /*