[PATCH v1 08/14] xen/riscv: introduce decode_cause() stuff

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

The patch introduces stuff needed to decode a reason of an
exception.

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
 xen/arch/riscv/traps.c | 88 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)

diff --git a/xen/arch/riscv/traps.c b/xen/arch/riscv/traps.c
index 3201b851ef..dd64f053a5 100644
--- a/xen/arch/riscv/traps.c
+++ b/xen/arch/riscv/traps.c
@@ -4,8 +4,96 @@
  *
  * RISC-V Trap handlers
  */
+#include <asm/csr.h>
+#include <asm/early_printk.h>
 #include <asm/processor.h>
 #include <asm/traps.h>
+#include <xen/errno.h>
+
+const char *decode_trap_cause(unsigned long cause)
+{
+    switch ( cause )
+    {
+    case CAUSE_MISALIGNED_FETCH:
+        return "Instruction Address Misaligned";
+    case CAUSE_FETCH_ACCESS:
+        return "Instruction Access Fault";
+    case CAUSE_ILLEGAL_INSTRUCTION:
+        return "Illegal Instruction";
+    case CAUSE_BREAKPOINT:
+        return "Breakpoint";
+    case CAUSE_MISALIGNED_LOAD:
+        return "Load Address Misaligned";
+    case CAUSE_LOAD_ACCESS:
+        return "Load Access Fault";
+    case CAUSE_MISALIGNED_STORE:
+        return "Store/AMO Address Misaligned";
+    case CAUSE_STORE_ACCESS:
+        return "Store/AMO Access Fault";
+    case CAUSE_USER_ECALL:
+        return "Environment Call from U-Mode";
+    case CAUSE_SUPERVISOR_ECALL:
+        return "Environment Call from S-Mode";
+    case CAUSE_MACHINE_ECALL:
+        return "Environment Call from M-Mode";
+    case CAUSE_FETCH_PAGE_FAULT:
+        return "Instruction Page Fault";
+    case CAUSE_LOAD_PAGE_FAULT:
+        return "Load Page Fault";
+    case CAUSE_STORE_PAGE_FAULT:
+        return "Store/AMO Page Fault";
+    case CAUSE_FETCH_GUEST_PAGE_FAULT:
+        return "Instruction Guest Page Fault";
+    case CAUSE_LOAD_GUEST_PAGE_FAULT:
+        return "Load Guest Page Fault";
+    case CAUSE_VIRTUAL_INST_FAULT:
+        return "Virtualized Instruction Fault";
+    case CAUSE_STORE_GUEST_PAGE_FAULT:
+        return "Guest Store/AMO Page Fault";
+    default:
+        return "UNKNOWN";
+    }
+}
+
+const char *decode_reserved_interrupt_cause(unsigned long irq_cause)
+{
+    switch ( irq_cause )
+    {
+    case IRQ_M_SOFT:
+        return "M-mode Software Interrupt";
+    case IRQ_M_TIMER:
+        return "M-mode TIMER Interrupt";
+    case IRQ_M_EXT:
+        return "M-mode TIMER Interrupt";
+    default:
+        return "UNKNOWN IRQ type";
+    }
+}
+
+const char *decode_interrupt_cause(unsigned long cause)
+{
+    unsigned long irq_cause = cause & ~CAUSE_IRQ_FLAG;
+
+    switch ( irq_cause )
+    {
+    case IRQ_S_SOFT:
+        return "Supervisor Software Interrupt";
+    case IRQ_S_TIMER:
+        return "Supervisor Timer Interrupt";
+    case IRQ_S_EXT:
+        return "Supervisor External Interrupt";
+    default:
+        return decode_reserved_interrupt_cause(irq_cause);
+    }
+}
+
+const char *decode_cause(unsigned long cause)
+{
+    if ( cause & CAUSE_IRQ_FLAG )
+        return decode_interrupt_cause(cause);
+
+    return decode_trap_cause(cause);
+}
 
 void __handle_exception(struct cpu_user_regs *cpu_regs)
 {
-- 
2.39.0