Re: [PATCH v26 01/28] mm: VM_SHADOW_STACK definition for riscv

From: Deepak Gupta <debug@rivosinc.com>
To: Paul Walmsley <pjw@kernel.org>
Cc: "Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Liam R. Howlett" <Liam.Howlett@oracle.com>,
	"Vlastimil Babka" <vbabka@suse.cz>,
	"Lorenzo Stoakes" <lorenzo.stoakes@oracle.com>,
	"Paul Walmsley" <paul.walmsley@sifive.com>,
	"Palmer Dabbelt" <palmer@dabbelt.com>,
	"Albert Ou" <aou@eecs.berkeley.edu>,
	"Conor Dooley" <conor@kernel.org>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Christian Brauner" <brauner@kernel.org>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Oleg Nesterov" <oleg@redhat.com>,
	"Eric Biederman" <ebiederm@xmission.com>,
	"Kees Cook" <kees@kernel.org>, "Jonathan Corbet" <corbet@lwn.net>,
	"Shuah Khan" <shuah@kernel.org>, "Jann Horn" <jannh@google.com>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Miguel Ojeda" <ojeda@kernel.org>,
	"Alex Gaynor" <alex.gaynor@gmail.com>,
	"Boqun Feng" <boqun.feng@gmail.com>,
	"Gary Guo" <gary@garyguo.net>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Andreas Hindborg" <a.hindborg@kernel.org>,
	"Alice Ryhl" <aliceryhl@google.com>,
	"Trevor Gross" <tmgross@umich.edu>,
	"Benno Lossin" <lossin@kernel.org>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, linux-riscv@lists.infradead.org,
	devicetree@vger.kernel.org, linux-arch@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org,
	alistair.francis@wdc.com, richard.henderson@linaro.org,
	jim.shu@sifive.com, andybnac@gmail.com, kito.cheng@sifive.com,
	charlie@rivosinc.com, atishp@rivosinc.com, evan@rivosinc.com,
	cleger@rivosinc.com, alexghiti@rivosinc.com,
	samitolvanen@google.com, broonie@kernel.org,
	rick.p.edgecombe@intel.com, rust-for-linux@vger.kernel.org,
	"Zong Li" <zong.li@sifive.com>,
	"David Hildenbrand" <david@redhat.com>,
	"Andreas Korb" <andreas.korb@aisec.fraunhofer.de>,
	"Valentin Haudiquet" <valentin.haudiquet@canonical.com>
Subject: Re: [PATCH v26 01/28] mm: VM_SHADOW_STACK definition for riscv
Date: Mon, 26 Jan 2026 13:56:21 -0800	[thread overview]
Message-ID: <aXfjBd7eCE3ypUnf@debug.ba.rivosinc.com> (raw)
In-Reply-To: <68e1702e-f803-2db2-0e16-53ecef4d9eb6@kernel.org>

Hi Paul,

Comment inlne.

On Wed, Jan 14, 2026 at 07:57:19PM -0700, Paul Walmsley wrote:
>On Thu, 11 Dec 2025, Deepak Gupta via B4 Relay wrote:
>
>> From: Deepak Gupta <debug@rivosinc.com>
>>
>> VM_HIGH_ARCH_5 is used for riscv
>>
>> Reviewed-by: Zong Li <zong.li@sifive.com>
>> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
>> Acked-by: David Hildenbrand <david@redhat.com>
>> Tested-by: Andreas Korb <andreas.korb@aisec.fraunhofer.de>
>> Tested-by: Valentin Haudiquet <valentin.haudiquet@canonical.com>
>> Signed-off-by: Deepak Gupta <debug@rivosinc.com>
>
>Here's what I'm planning to queue, after updating it after Lorenzo's mm
>changes.  Please let me know if you want to change anything.

Yes looks good to me. Thanks a lot.

>
>
>- Paul
>
>From: Deepak Gupta <debug@rivosinc.com>
>Date: Wed, 19 Nov 2025 09:55:05 -0700
>
>mm: add VM_SHADOW_STACK definition for riscv
>
>VM_HIGH_ARCH_5 is used for riscv.
>
>Reviewed-by: Zong Li <zong.li@sifive.com>
>Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
>Acked-by: David Hildenbrand <david@redhat.com>
>Signed-off-by: Deepak Gupta <debug@rivosinc.com>
>Tested-by: Andreas Korb <andreas.korb@aisec.fraunhofer.de> # QEMU, custom CVA6
>Tested-by: Valentin Haudiquet <valentin.haudiquet@canonical.com>
>Link: https://patch.msgid.link/20251112-v5_user_cfi_series-v23-1-b55691eacf4f@rivosinc.com
>[pjw@kernel.org: clarify subject; update to apply]
>Signed-off-by: Paul Walmsley <pjw@kernel.org>
>---
> include/linux/mm.h | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
>diff --git a/include/linux/mm.h b/include/linux/mm.h
>index 15076261d0c2..de912272c5f9 100644
>--- a/include/linux/mm.h
>+++ b/include/linux/mm.h
>@@ -359,7 +359,7 @@ enum {
> 	DECLARE_VMA_BIT_ALIAS(PKEY_BIT2, HIGH_ARCH_2),
> 	DECLARE_VMA_BIT_ALIAS(PKEY_BIT3, HIGH_ARCH_3),
> 	DECLARE_VMA_BIT_ALIAS(PKEY_BIT4, HIGH_ARCH_4),
>-#if defined(CONFIG_X86_USER_SHADOW_STACK)
>+#if defined(CONFIG_X86_USER_SHADOW_STACK) || defined(CONFIG_RISCV_USER_CFI)
> 	/*
> 	 * VM_SHADOW_STACK should not be set with VM_SHARED because of lack of
> 	 * support core mm.
>@@ -460,7 +460,8 @@ enum {
> #define VM_PKEY_BIT4  VM_NONE
> #endif /* CONFIG_ARCH_PKEY_BITS > 4 */
> #endif /* CONFIG_ARCH_HAS_PKEYS */
>-#if defined(CONFIG_X86_USER_SHADOW_STACK) || defined(CONFIG_ARM64_GCS)
>+#if defined(CONFIG_X86_USER_SHADOW_STACK) || defined(CONFIG_ARM64_GCS) || \
>+	defined(CONFIG_RISCV_USER_CFI)
> #define VM_SHADOW_STACK	INIT_VM_FLAG(SHADOW_STACK)
> #else
> #define VM_SHADOW_STACK	VM_NONE
>-- 
>2.51.0
>
>
>
>