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Message-Id: <20240625-arm64-gcs-v9-6-0f634469b8f0@kernel.org>
Date: Tue, 25 Jun 2024 15:57:34 +0100
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>,
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>, Kees Cook <kees@...nel.org>
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>,
Ross Burton <ross.burton@....com>, 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 v9 06/39] arm64/sysreg: Add definitions for architected GCS
caps
The architecture defines a format for guarded control stack caps, used
to mark the top of an unused GCS in order to limit the potential for
exploitation via stack switching. Add definitions associated with these.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@...aro.org>
Signed-off-by: Mark Brown <broonie@...nel.org>
---
arch/arm64/include/asm/sysreg.h | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index af3b206fa423..325a1daa98ed 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -1064,6 +1064,26 @@
#define POE_RXW UL(0x7)
#define POE_MASK UL(0xf)
+/*
+ * Definitions for Guarded Control Stack
+ */
+
+#define GCS_CAP_ADDR_MASK GENMASK(63, 12)
+#define GCS_CAP_ADDR_SHIFT 12
+#define GCS_CAP_ADDR_WIDTH 52
+#define GCS_CAP_ADDR(x) FIELD_GET(GCS_CAP_ADDR_MASK, x)
+
+#define GCS_CAP_TOKEN_MASK GENMASK(11, 0)
+#define GCS_CAP_TOKEN_SHIFT 0
+#define GCS_CAP_TOKEN_WIDTH 12
+#define GCS_CAP_TOKEN(x) FIELD_GET(GCS_CAP_TOKEN_MASK, x)
+
+#define GCS_CAP_VALID_TOKEN 0x1
+#define GCS_CAP_IN_PROGRESS_TOKEN 0x5
+
+#define GCS_CAP(x) ((((unsigned long)x) & GCS_CAP_ADDR_MASK) | \
+ GCS_CAP_VALID_TOKEN)
+
#define ARM64_FEATURE_FIELD_BITS 4
/* Defined for compatibility only, do not add new users. */
--
2.39.2
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