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From: Mark Brown <broonie@kernel.org>
Date: Sat, 03 Feb 2024 12:25:29 +0000
Subject: [PATCH v8 03/38] mman: Add map_shadow_stack() flags
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To: Catalin Marinas <catalin.marinas@arm.com>, 
 Will Deacon <will@kernel.org>, Jonathan Corbet <corbet@lwn.net>, 
 Andrew Morton <akpm@linux-foundation.org>, Marc Zyngier <maz@kernel.org>, 
 Oliver Upton <oliver.upton@linux.dev>, James Morse <james.morse@arm.com>, 
 Suzuki K Poulose <suzuki.poulose@arm.com>, Arnd Bergmann <arnd@arndb.de>, 
 Oleg Nesterov <oleg@redhat.com>, Eric Biederman <ebiederm@xmission.com>, 
 Kees Cook <keescook@chromium.org>, Shuah Khan <shuah@kernel.org>, 
 "Rick P. Edgecombe" <rick.p.edgecombe@intel.com>, 
 Deepak Gupta <debug@rivosinc.com>, Ard Biesheuvel <ardb@kernel.org>, 
 Szabolcs Nagy <Szabolcs.Nagy@arm.com>
Cc: "H.J. Lu" <hjl.tools@gmail.com>, 
 Paul Walmsley <paul.walmsley@sifive.com>, 
 Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu>, 
 Florian Weimer <fweimer@redhat.com>, Christian Brauner <brauner@kernel.org>, 
 Thiago Jung Bauermann <thiago.bauermann@linaro.org>, 
 linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, 
 kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, 
 linux-arch@vger.kernel.org, linux-mm@kvack.org, 
 linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, 
 linux-riscv@lists.infradead.org, Mark Brown <broonie@kernel.org>

In preparation for adding arm64 GCS support make the map_shadow_stack()
SHADOW_STACK_SET_TOKEN flag generic and add _SET_MARKER. The existing
flag indicats that a token usable for stack switch should be added to
the top of the newly mapped GCS region while the new flag indicates that
a top of stack marker suitable for use by unwinders should be added
above that.

For arm64 the top of stack marker is all bits 0.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/x86/include/uapi/asm/mman.h | 3 ---
 include/uapi/asm-generic/mman.h  | 4 ++++
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/uapi/asm/mman.h b/arch/x86/include/uapi/asm/mman.h
index 46cdc941f958..ac1e6277212b 100644
--- a/arch/x86/include/uapi/asm/mman.h
+++ b/arch/x86/include/uapi/asm/mman.h
@@ -5,9 +5,6 @@
 #define MAP_32BIT	0x40		/* only give out 32bit addresses */
 #define MAP_ABOVE4G	0x80		/* only map above 4GB */
 
-/* Flags for map_shadow_stack(2) */
-#define SHADOW_STACK_SET_TOKEN	(1ULL << 0)	/* Set up a restore token in the shadow stack */
-
 #include <asm-generic/mman.h>
 
 #endif /* _ASM_X86_MMAN_H */
diff --git a/include/uapi/asm-generic/mman.h b/include/uapi/asm-generic/mman.h
index 57e8195d0b53..d6a282687af5 100644
--- a/include/uapi/asm-generic/mman.h
+++ b/include/uapi/asm-generic/mman.h
@@ -19,4 +19,8 @@
 #define MCL_FUTURE	2		/* lock all future mappings */
 #define MCL_ONFAULT	4		/* lock all pages that are faulted in */
 
+#define SHADOW_STACK_SET_TOKEN (1ULL << 0)     /* Set up a restore token in the shadow stack */
+#define SHADOW_STACK_SET_MARKER (1ULL << 1)     /* Set up a top of stack merker in the shadow stack */
+
+
 #endif /* __ASM_GENERIC_MMAN_H */

-- 
2.30.2