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Message-Id: <20240203-arm64-gcs-v8-11-c9fec77673ef@kernel.org>
Date: Sat, 03 Feb 2024 12:25:37 +0000
From: Mark Brown <broonie@...nel.org>
To: Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>, Jonathan Corbet <corbet@....net>,
Andrew Morton <akpm@...ux-foundation.org>, Marc Zyngier <maz@...nel.org>,
Oliver Upton <oliver.upton@...ux.dev>, James Morse <james.morse@....com>,
Suzuki K Poulose <suzuki.poulose@....com>, Arnd Bergmann <arnd@...db.de>,
Oleg Nesterov <oleg@...hat.com>, Eric Biederman <ebiederm@...ssion.com>,
Kees Cook <keescook@...omium.org>, Shuah Khan <shuah@...nel.org>,
"Rick P. Edgecombe" <rick.p.edgecombe@...el.com>,
Deepak Gupta <debug@...osinc.com>, Ard Biesheuvel <ardb@...nel.org>,
Szabolcs Nagy <Szabolcs.Nagy@....com>
Cc: "H.J. Lu" <hjl.tools@...il.com>,
Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>,
Florian Weimer <fweimer@...hat.com>, Christian Brauner <brauner@...nel.org>,
Thiago Jung Bauermann <thiago.bauermann@...aro.org>,
linux-arm-kernel@...ts.infradead.org, linux-doc@...r.kernel.org,
kvmarm@...ts.linux.dev, linux-fsdevel@...r.kernel.org,
linux-arch@...r.kernel.org, linux-mm@...ck.org,
linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-riscv@...ts.infradead.org, Mark Brown <broonie@...nel.org>
Subject: [PATCH v8 11/38] mm: Define VM_SHADOW_STACK for arm64 when we
support GCS
Use VM_HIGH_ARCH_5 for guarded control stack pages.
Signed-off-by: Mark Brown <broonie@...nel.org>
---
Documentation/filesystems/proc.rst | 2 +-
fs/proc/task_mmu.c | 3 +++
include/linux/mm.h | 12 +++++++++++-
3 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 104c6d047d9b..0392c3b74650 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -570,7 +570,7 @@ encoded manner. The codes are the following:
mt arm64 MTE allocation tags are enabled
um userfaultfd missing tracking
uw userfaultfd wr-protect tracking
- ss shadow stack page
+ ss shadow/guarded control stack page
== =======================================
Note that there is no guarantee that every flag and associated mnemonic will
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index ff2c601f7d1c..fb0633d8e309 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -702,6 +702,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
#endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
#ifdef CONFIG_ARCH_HAS_USER_SHADOW_STACK
[ilog2(VM_SHADOW_STACK)] = "ss",
+#endif
+#ifdef CONFIG_ARM64_GCS
+ [ilog2(VM_SHADOW_STACK)] = "ss",
#endif
};
size_t i;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0b1139c5df60..6cc304c90c63 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -352,7 +352,17 @@ extern unsigned int kobjsize(const void *objp);
* for more details on the guard size.
*/
# define VM_SHADOW_STACK VM_HIGH_ARCH_5
-#else
+#endif
+
+#if defined(CONFIG_ARM64_GCS)
+/*
+ * arm64's Guarded Control Stack implements similar functionality and
+ * has similar constraints to shadow stacks.
+ */
+# define VM_SHADOW_STACK VM_HIGH_ARCH_5
+#endif
+
+#ifndef VM_SHADOW_STACK
# define VM_SHADOW_STACK VM_NONE
#endif
--
2.30.2
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