From mboxrd@z Thu Jan 1 00:00:00 1970 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 3445C31C572 for ; Mon, 8 Sep 2025 21:32:13 +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=1757367134; cv=none; b=EqwnZrNWSiolDOPlxId3QDcTtM2JA6uU85nhDmZMHlNAhuklzDrubPj7lW9Oi9SUWHrJjZe/nW+V34LvanpclJ63m+1rNGpKMuky34VScIARyeH9u10Bg1qGFhNGrQzCYFhI36AFSt1XTdfVEsrQ16dvNwCaXVQF9DiacY4rY4g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757367134; c=relaxed/simple; bh=e8g7UdBhqrXKfk2gzjboAafceUj4gAwYFSFlErrzvSc=; h=Message-ID:From:To:Cc:Subject:References:MIME-Version: Content-Type:Date; b=uFnQ9bMQV2WTRguaCovBpdZnVPdi7Iuj75KeRew8Ga8tmwGkHW4H5zsKTOXe89Bdy6FKbXsXkha081wbWxefHJThNVnxCZMYHnvnI0dpdTRAMV8Hy0URB97SVvkmHC8RKampYib3I3AwUY+kQWn5YpXkkxNUbxLZUD/nbYnNyNA= 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=S8Q7woBX; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Xo/MneMZ; 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="S8Q7woBX"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Xo/MneMZ" Message-ID: <20250908212926.673713522@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1757367131; 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=NSKUyyV86FuSpvpTInpZTwVe/DTQioaMYANjUCDRIuI=; b=S8Q7woBXW9Vglh33wNVMoV/clp/ZiOAOA46CnEZhOUxqwHy9fISqP8Kw7aW9z+PzwTGNHu TLmUrgb/OkSncq6cazVy4s/S29yVrh2+cLQssmpKV9snx3U4hXX0PMnAOGxhSyfKJReTsY E2eEeUfURIa0KsyWu6X0VzzErm5w4okXdD8wol9NdUUh7o1K16jVLVvjDCgiQTF0Q/8Axf R37y7Pm2n/DMDLTyAnzURZDEZHQ0iNSDrC67tzPdSs2YkJTlMMzfAHa10UDdUfCVQu2iDW 9fajEa2yeP8KHSMHrQ+LETmosqtwDKzu2eBZ/PcIfFeXnyl676zRUvedicKIsQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1757367131; 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=NSKUyyV86FuSpvpTInpZTwVe/DTQioaMYANjUCDRIuI=; b=Xo/MneMZ0EDaX93bisjqVsODxJ8VBcykuDzFdfD9Ts2OCMGK66MdMZajcwKdS96Ua1q342 QwOtdw0qNkXyeSDQ== From: Thomas Gleixner To: LKML Cc: Michael Jeanson , 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 V4 22/36] rseq: Use static branch for syscall exit debug when GENERIC_IRQ_ENTRY=y References: <20250908212737.353775467@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Date: Mon, 8 Sep 2025 23:32:10 +0200 (CEST) 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(); } - rseq_syscall(regs); + rseq_debug_syscall_return(regs); /* * 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 = 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 */ --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -470,12 +470,7 @@ void __rseq_handle_notify_resume(struct 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; @@ -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=n 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 /*