[wip] Enable aarch64 exceptions

src/arch/aarch64/traps.rs

@@ -0,0 +1,44 @@
+// Interrupt handling
+
+
+// The base address is given by VBAR_ELn and each entry has a defined offset from this
+// base address. Each table has 16 entries, with each entry being 128 bytes (32 instructions)
+// in size. The table effectively consists of 4 sets of 4 entries.
+
+VBAR_EL1, VBAR_EL2, VBAR_EL3
+
+CurrentEL with SP0: +0x0
+
+    Synchronous
+    IRQ/vIRQ
+    FIQ
+    SError/vSError
+
+CurrentEL with SPx: +0x200
+
+    Synchronous
+    IRQ/vIRQ
+    FIQ
+    SError/vSError
+
+Lower EL using AArch64: +0x400
+
+    Synchronous
+    IRQ/vIRQ
+    FIQ
+    SError/vSError
+
+Lower EL using AArch32: +0x600
+
+    Synchronous
+    IRQ/vIRQ
+    FIQ
+    SError/vSError
+
+// When the processor takes an exception to AArch64 execution state,
+// all of the PSTATE interrupt masks is set automatically. This means
+// that further exceptions are disabled. If software is to support
+// nested exceptions, for example, to allow a higher priority interrupt
+// to interrupt the handling of a lower priority source, then software needs
+// to explicitly re-enable interrupts
+