mman: Add map_shadow_stack() flags

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 indicates 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.

Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Yury Khrustalev <yury.khrustalev@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20241001-arm64-gcs-v13-5-222b78d87eee@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/x86/include/uapi/asm/mman.h b/arch/x86/include/uapi/asm/mman.h
index 46cdc941f9586ac227c02a16705cf4397b629423..ac1e6277212b90437bf7611c4024a48a8ab9f31a 100644 (file)
--- 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 57e8195d0b538b213318ce552f32dd3a660171d5..5e3d61ddbd8c12cda03a48cb79bbe5b70ad3f77b 100644 (file)
--- 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 marker in the shadow stack */
+
+
 #endif /* __ASM_GENERIC_MMAN_H */