Added MMU

src/cpu/exception.c

@@ -0,0 +1,25 @@
+#include "exception.h"
+
+#include <stdio.h>
+
+void exception_trigger(rv32_cpu_t* cpu, uint32_t scause)
+{
+    // An exception can only be triggered by the CPU itself,
+    // so we know we already own the mutex
+    // We are in the CPU thread itself, but we need
+    // the return of this function to be the beginning of
+    // the cpu loop
+    // To achieve that, we can just call cpu_loop (noreturn)
+    // at the end of this function
+
+    // Save execution context, so that 'mret/sret/..' can restore it
+    // TODO
+
+    // Set PC to STVEC, and set SCAUSE
+    // TODO: If PC cannot be mmu_resolved, throw a 'double fault' ?
+    cpu->pc = cpu->csr[CSR_STVEC];
+    cpu->csr[CSR_SCAUSE] = scause;
+
+    pthread_mutex_unlock(&cpu0_mutex);
+    cpu_loop(cpu);
+}

src/cpu/exception.h

@@ -0,0 +1,19 @@
+#ifndef EXCEPTION_H
+#define EXCEPTION_H
+
+#include "rv32cpu.h"
+
+void exception_trigger(rv32_cpu_t* cpu, uint32_t scause);
+
+#define SCAUSE_INSTRUCTION_MISSALIGNED 0x0
+#define SCAUSE_INSTRUCTION_ACCESS_FAULT 0x1
+#define SCAUSE_ILLEGAL_INSTRUCTION 0x2
+#define SCAUSE_BREAKPOINT 0x3
+#define SCAUSE_LOAD_ACCESS_FAULT 0x5
+#define SCAUSE_AMO_ADDRESS_MISALIGNED 0x6
+#define SCAUSE_ENVIRONMENT_CALL 0x8
+#define SCAUSE_INSTRUCTION_PAGE_FAULT 0xC
+#define SCAUSE_LOAD_PAGE_FAULT 0xD
+#define SCAUSE_STORE_AMO_PAGE_FAULT 0xF
+
+#endif

src/cpu/rv32cpu.c

@@ -531,7 +531,7 @@ static void cpu_execute(rv32_cpu_t* cpu, instruction_t* instruction)
 							switch(instruction->func7)
 							{
 								case FUNC7_SFENCEVMA:
-									fprintf(stderr, "SFENCE.VMA: Guest kernel must think we have an MMU. We have none.\n");
+									// TODO : Check if we really need to do something on SFENCE.VMA ?
 									break;
 								case FUNC7_WFI:
 									fprintf(stderr, "WFI: Guest kernel must think we have interrupts. We have none. Halting simulation.\n");