[PATCH v1 06/14] xen/riscv: introduce exception context

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

The patch introduces a set of registers which should be saved to and
restored from a stack after an exception occurs and a set of defines
which will be used during exception context saving/restoring.

Originally <asm/processor.h> header was introduced in the patch series
from Bobby so mostly it was re-used and removed unneeded things from
it now.

Signed-off-by: Bobby Eshleman <bobby.eshleman@xxxxxxxxx>
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
 xen/arch/riscv/include/asm/processor.h | 114 +++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 xen/arch/riscv/include/asm/processor.h

diff --git a/xen/arch/riscv/include/asm/processor.h 
b/xen/arch/riscv/include/asm/processor.h
new file mode 100644
index 0000000000..5898a09ce6
--- /dev/null
+++ b/xen/arch/riscv/include/asm/processor.h
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: MIT */
+/******************************************************************************
+ *
+ * Copyright 2019 (C) Alistair Francis <alistair.francis@xxxxxxx>
+ * Copyright 2021 (C) Bobby Eshleman <bobby.eshleman@xxxxxxxxx>
+ * Copyright 2023 (C) Vates
+ *
+ */
+
+#ifndef _ASM_RISCV_PROCESSOR_H
+#define _ASM_RISCV_PROCESSOR_H
+
+#include <asm/types.h>
+
+#define RISCV_CPU_USER_REGS_zero        0
+#define RISCV_CPU_USER_REGS_ra          1
+#define RISCV_CPU_USER_REGS_sp          2
+#define RISCV_CPU_USER_REGS_gp          3
+#define RISCV_CPU_USER_REGS_tp          4
+#define RISCV_CPU_USER_REGS_t0          5
+#define RISCV_CPU_USER_REGS_t1          6
+#define RISCV_CPU_USER_REGS_t2          7
+#define RISCV_CPU_USER_REGS_s0          8
+#define RISCV_CPU_USER_REGS_s1          9
+#define RISCV_CPU_USER_REGS_a0          10
+#define RISCV_CPU_USER_REGS_a1          11
+#define RISCV_CPU_USER_REGS_a2          12
+#define RISCV_CPU_USER_REGS_a3          13
+#define RISCV_CPU_USER_REGS_a4          14
+#define RISCV_CPU_USER_REGS_a5          15
+#define RISCV_CPU_USER_REGS_a6          16
+#define RISCV_CPU_USER_REGS_a7          17
+#define RISCV_CPU_USER_REGS_s2          18
+#define RISCV_CPU_USER_REGS_s3          19
+#define RISCV_CPU_USER_REGS_s4          20
+#define RISCV_CPU_USER_REGS_s5          21
+#define RISCV_CPU_USER_REGS_s6          22
+#define RISCV_CPU_USER_REGS_s7          23
+#define RISCV_CPU_USER_REGS_s8          24
+#define RISCV_CPU_USER_REGS_s9          25
+#define RISCV_CPU_USER_REGS_s10         26
+#define RISCV_CPU_USER_REGS_s11         27
+#define RISCV_CPU_USER_REGS_t3          28
+#define RISCV_CPU_USER_REGS_t4          29
+#define RISCV_CPU_USER_REGS_t5          30
+#define RISCV_CPU_USER_REGS_t6          31
+#define RISCV_CPU_USER_REGS_sepc        32
+#define RISCV_CPU_USER_REGS_sstatus     33
+#define RISCV_CPU_USER_REGS_pregs       34
+#define RISCV_CPU_USER_REGS_last        35
+
+#define RISCV_CPU_USER_REGS_OFFSET(x)   ((RISCV_CPU_USER_REGS_##x) * 
__SIZEOF_POINTER__)
+#define RISCV_CPU_USER_REGS_SIZE        RISCV_CPU_USER_REGS_OFFSET(last)
+
+#ifndef __ASSEMBLY__
+
+/* On stack VCPU state */
+struct cpu_user_regs
+{
+    register_t zero;
+    register_t ra;
+    register_t sp;
+    register_t gp;
+    register_t tp;
+    register_t t0;
+    register_t t1;
+    register_t t2;
+    register_t s0;
+    register_t s1;
+    register_t a0;
+    register_t a1;
+    register_t a2;
+    register_t a3;
+    register_t a4;
+    register_t a5;
+    register_t a6;
+    register_t a7;
+    register_t s2;
+    register_t s3;
+    register_t s4;
+    register_t s5;
+    register_t s6;
+    register_t s7;
+    register_t s8;
+    register_t s9;
+    register_t s10;
+    register_t s11;
+    register_t t3;
+    register_t t4;
+    register_t t5;
+    register_t t6;
+    register_t sepc;
+    register_t sstatus;
+    /* pointer to previous stack_cpu_regs */
+    register_t pregs;
+};
+
+static inline void wait_for_interrupt(void)
+{
+    __asm__ __volatile__ ("wfi");
+}
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_RISCV_PROCESSOR_H */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
-- 
2.39.0