From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.mindbit.ro (xs1.mindbit.ro [80.86.107.70]) (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 E36E34C9574; Wed, 8 Jul 2026 18:36:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.86.107.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783535781; cv=none; b=R5zdFaS+++3Xn0w/O9kkSY/+YIFvZlEmrYO8uuKbNeck8czEfosB8RgOAhmNsvL+QjhFK6worxDaEiR7zE4SGe+QqOy1JjfxDRvkY46eV+WhTCGPzLQNovjcBFYU4+9wbXNz5YDwLu0JEK05xQB1opW3OEDQiKsmr+WZfoguvck= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783535781; c=relaxed/simple; bh=Y1A7c5g51w31PW2cY9eGOYb8oZVqwqAfG/O5QtGpzXg=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=d1MUJaTLHTaO4GrQG2YEWuXccOGIVQcjqE8OlcDA2OnnzTuJCnb3Mn0zEZdVUGTYbwArJnRrOo6D/dAq2rwFSvlfdSzOXcoTvtB6bZT5ZCCeDojWQ9jNJwCUtncNOGs+q2BiyHnQczYIKjBpw2Qs75iW5Yk7y0sMIB/CCiWXyg0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=rendec.net; spf=pass smtp.mailfrom=rendec.net; dkim=pass (2048-bit key) header.d=rendec.net header.i=@rendec.net header.b=R0pckaM7; arc=none smtp.client-ip=80.86.107.70 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=rendec.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rendec.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=rendec.net header.i=@rendec.net header.b="R0pckaM7" Received: from bat.kanata.rendec.net (unknown [24.114.111.125]) by mail.mindbit.ro (Postfix) with ESMTPSA id A4061C3435; Wed, 8 Jul 2026 21:35:54 +0300 (EEST) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.mindbit.ro A4061C3435 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rendec.net; s=default; t=1783535777; bh=HOFoesOyB88RJQpCsNVT6CnljJeq85zHo9ievtK6il8=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=R0pckaM7uzKJhnfLsd+EasA5iL0B7ZA4xUo2QedrlgePDqSCeceDdoKrCaUXSgH75 15MPZ33HpRCU30hqcMI0PUJAA4ul+9XUwxAhJeXTpBoywEuKewGCk7m21xK7GBO94b NpDa7pro6OWmXqh5IS/WT+qx6ABBrkCA+Kv5g9jMDrLVH+mh9k+/398rw04b/Uiitl a9blgckrqg3HTXMb7xcAzYPWQFRHvTBk4ekkJmwrZessc3xf9tFXhmpN0qrpZBt8yq 5Qao1qyCtvtsSHKBGAM0cGKH+LVrTaTCbKcejqQuUrZPKj01pL+BpzMYflQ9YS3rRx JbQnyYBWoKGdQ== Message-ID: Subject: Re: [patch 05/18] powerpc/syscall: Use syscall_enter_from_user_mode_randomize_stack() From: Radu Rendec To: Thomas Gleixner , LKML Cc: Peter Zijlstra , Michael Ellerman , Shrikanth Hegde , linuxppc-dev@lists.ozlabs.org, Kees Cook , Huacai Chen , loongarch@lists.linux.dev, Paul Walmsley , Palmer Dabbelt , linux-riscv@lists.infradead.org, Sven Schnelle , linux-s390@vger.kernel.org, x86@kernel.org, Mark Rutland , Jinjie Ruan , Andy Lutomirski , Oleg Nesterov , Richard Henderson , Russell King , Catalin Marinas , Guo Ren , Geert Uytterhoeven , Thomas Bogendoerfer , Helge Deller , Yoshinori Sato , Richard Weinberger , Chris Zankel , linux-arm-kernel@lists.infradead.org, linux-alpha@vger.kernel.org, linux-csky@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-sh@vger.kernel.org, linux-um@lists.infradead.org, Arnd Bergmann , Vineet Gupta , Will Deacon , Brian Cain , Michal Simek , Dinh Nguyen , "David S. Miller" , Andreas Larsson , linux-snps-arc@lists.infradead.org, linux-hexagon@vger.kernel.org, linux-openrisc@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, Michal =?ISO-8859-1?Q?Such=E1nek?= , Jonathan Corbet , linux-doc@vger.kernel.org Date: Wed, 08 Jul 2026 14:35:48 -0400 In-Reply-To: <20260707190253.918861529@kernel.org> References: <20260707181957.433213175@kernel.org> <20260707190253.918861529@kernel.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.3 (3.58.3-1.fc43) Precedence: bulk X-Mailing-List: linux-sh@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2026-07-07 at 21:06 +0200, Thomas Gleixner wrote: > syscall_enter_from_user_mode_randomize_stack() replaces > syscall_enter_from_user_mode() and the subsequent invocation of > add_random_kstack_offset(). >=20 > The advantage is that it applies the stack randomization right after > enter_from_user_mode() and thereby avoids the overhead of get/put_cpu_var= () > as that code is invoked with interrupts disabled. >=20 > No functional change. >=20 > Signed-off-by: Thomas Gleixner > Cc: Michael Ellerman > Cc: Shrikanth Hegde > Cc: linuxppc-dev@lists.ozlabs.org > --- > =C2=A0arch/powerpc/kernel/syscall.c |=C2=A0=C2=A0=C2=A0 4 +--- > =C2=A01 file changed, 1 insertion(+), 3 deletions(-) >=20 > --- a/arch/powerpc/kernel/syscall.c > +++ b/arch/powerpc/kernel/syscall.c > @@ -2,7 +2,6 @@ > =C2=A0 > =C2=A0#include > =C2=A0#include > -#include > =C2=A0#include > =C2=A0 > =C2=A0#include > @@ -19,8 +18,7 @@ notrace long system_call_exception(struc > =C2=A0 long ret; > =C2=A0 syscall_fn f; > =C2=A0 > - r0 =3D syscall_enter_from_user_mode(regs, r0); > - add_random_kstack_offset(); > + r0 =3D syscall_enter_from_user_mode_randomize_stack(regs, r0); > =C2=A0 > =C2=A0 if (unlikely(r0 >=3D NR_syscalls)) { > =C2=A0 if (unlikely(trap_is_unsupported_scv(regs))) { Reviewed-by: Radu Rendec