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@linaro.org Signed-off-by: Mark Brown broonie@kernel.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 4a9ea103817e..b8d8718a7b8b 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -1077,6 +1077,26 @@ #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. */