aarch64: add sve_context struct and related defines from linux v4.15

signal context definitions for scalable vector extension new in commit
d0b8cd3187889476144bd9b13bf36a932c3e7952

Author: Szabolcs Nagy

arch/aarch64/bits/signal.h

@@ -25,6 +25,7 @@ typedef struct sigcontext {
 #define FPSIMD_MAGIC 0x46508001
 #define ESR_MAGIC 0x45535201
 #define EXTRA_MAGIC 0x45585401
+#define SVE_MAGIC 0x53564501
 struct _aarch64_ctx {
 	unsigned int magic;
 	unsigned int size;
@@ -45,6 +46,44 @@ struct extra_context {
 	unsigned int size;
 	unsigned int __reserved[3];
 };
+struct sve_context {
+	struct _aarch64_ctx head;
+	unsigned short vl;
+	unsigned short __reserved[3];
+};
+#define SVE_VQ_BYTES		16
+#define SVE_VQ_MIN		1
+#define SVE_VQ_MAX		512
+#define SVE_VL_MIN		(SVE_VQ_MIN * SVE_VQ_BYTES)
+#define SVE_VL_MAX		(SVE_VQ_MAX * SVE_VQ_BYTES)
+#define SVE_NUM_ZREGS		32
+#define SVE_NUM_PREGS		16
+#define sve_vl_valid(vl) \
+	((vl) % SVE_VQ_BYTES == 0 && (vl) >= SVE_VL_MIN && (vl) <= SVE_VL_MAX)
+#define sve_vq_from_vl(vl)	((vl) / SVE_VQ_BYTES)
+#define sve_vl_from_vq(vq)	((vq) * SVE_VQ_BYTES)
+#define SVE_SIG_ZREG_SIZE(vq)	((unsigned)(vq) * SVE_VQ_BYTES)
+#define SVE_SIG_PREG_SIZE(vq)	((unsigned)(vq) * (SVE_VQ_BYTES / 8))
+#define SVE_SIG_FFR_SIZE(vq)	SVE_SIG_PREG_SIZE(vq)
+#define SVE_SIG_REGS_OFFSET					\
+	((sizeof(struct sve_context) + (SVE_VQ_BYTES - 1))	\
+		/ SVE_VQ_BYTES * SVE_VQ_BYTES)
+#define SVE_SIG_ZREGS_OFFSET	SVE_SIG_REGS_OFFSET
+#define SVE_SIG_ZREG_OFFSET(vq, n) \
+	(SVE_SIG_ZREGS_OFFSET + SVE_SIG_ZREG_SIZE(vq) * (n))
+#define SVE_SIG_ZREGS_SIZE(vq) \
+	(SVE_SIG_ZREG_OFFSET(vq, SVE_NUM_ZREGS) - SVE_SIG_ZREGS_OFFSET)
+#define SVE_SIG_PREGS_OFFSET(vq) \
+	(SVE_SIG_ZREGS_OFFSET + SVE_SIG_ZREGS_SIZE(vq))
+#define SVE_SIG_PREG_OFFSET(vq, n) \
+	(SVE_SIG_PREGS_OFFSET(vq) + SVE_SIG_PREG_SIZE(vq) * (n))
+#define SVE_SIG_PREGS_SIZE(vq) \
+	(SVE_SIG_PREG_OFFSET(vq, SVE_NUM_PREGS) - SVE_SIG_PREGS_OFFSET(vq))
+#define SVE_SIG_FFR_OFFSET(vq) \
+	(SVE_SIG_PREGS_OFFSET(vq) + SVE_SIG_PREGS_SIZE(vq))
+#define SVE_SIG_REGS_SIZE(vq) \
+	(SVE_SIG_FFR_OFFSET(vq) + SVE_SIG_FFR_SIZE(vq) - SVE_SIG_REGS_OFFSET)
+#define SVE_SIG_CONTEXT_SIZE(vq) (SVE_SIG_REGS_OFFSET + SVE_SIG_REGS_SIZE(vq))
 #else
 typedef struct {
 	long double __regs[18+256];