target/avr: CPU class: Add memory management support

This patch introduces three memory-management-related functions
that will become part of AVR CPU class object.

[AM: Split a larger AVR introduction patch into logical units]
Suggested-by: Aleksandar Markovic <aleksandar.m.mail@gmail.com>
Co-developed-by: Michael Rolnik <mrolnik@gmail.com>
Co-developed-by: Sarah Harris <S.E.Harris@kent.ac.uk>
Signed-off-by: Michael Rolnik <mrolnik@gmail.com>
Signed-off-by: Sarah Harris <S.E.Harris@kent.ac.uk>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Aleksandar Markovic <aleksandar.m.mail@gmail.com>
Acked-by: Igor Mammedov <imammedo@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Thomas Huth <huth@tuxfamily.org>
Message-Id: <20200705140315.260514-5-huth@tuxfamily.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

target/avr/cpu.c

@@ -203,6 +203,9 @@ static void avr_cpu_class_init(ObjectClass *oc, void *data)
     cc->cpu_exec_interrupt = avr_cpu_exec_interrupt;
     cc->dump_state = avr_cpu_dump_state;
     cc->set_pc = avr_cpu_set_pc;
+    cc->memory_rw_debug = avr_cpu_memory_rw_debug;
+    cc->get_phys_page_debug = avr_cpu_get_phys_page_debug;
+    cc->tlb_fill = avr_cpu_tlb_fill;
     cc->disas_set_info = avr_cpu_disas_set_info;
     cc->tcg_initialize = avr_cpu_tcg_init;
     cc->synchronize_from_tb = avr_cpu_synchronize_from_tb;

target/avr/helper.c

@@ -87,3 +87,53 @@ void avr_cpu_do_interrupt(CPUState *cs)
 
     cs->exception_index = -1;
 }
+
+int avr_cpu_memory_rw_debug(CPUState *cs, vaddr addr, uint8_t *buf,
+                            int len, bool is_write)
+{
+    return cpu_memory_rw_debug(cs, addr, buf, len, is_write);
+}
+
+hwaddr avr_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
+{
+    return addr; /* I assume 1:1 address correspondance */
+}
+
+bool avr_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
+                      MMUAccessType access_type, int mmu_idx,
+                      bool probe, uintptr_t retaddr)
+{
+    int prot = 0;
+    MemTxAttrs attrs = {};
+    uint32_t paddr;
+
+    address &= TARGET_PAGE_MASK;
+
+    if (mmu_idx == MMU_CODE_IDX) {
+        /* access to code in flash */
+        paddr = OFFSET_CODE + address;
+        prot = PAGE_READ | PAGE_EXEC;
+        if (paddr + TARGET_PAGE_SIZE > OFFSET_DATA) {
+            error_report("execution left flash memory");
+            abort();
+        }
+    } else if (address < NUMBER_OF_CPU_REGISTERS + NUMBER_OF_IO_REGISTERS) {
+        /*
+         * access to CPU registers, exit and rebuilt this TB to use full access
+         * incase it touches specially handled registers like SREG or SP
+         */
+        AVRCPU *cpu = AVR_CPU(cs);
+        CPUAVRState *env = &cpu->env;
+        env->fullacc = 1;
+        cpu_loop_exit_restore(cs, retaddr);
+    } else {
+        /* access to memory. nothing special */
+        paddr = OFFSET_DATA + address;
+        prot = PAGE_READ | PAGE_WRITE;
+    }
+
+    tlb_set_page_with_attrs(cs, address, paddr, attrs, prot,
+                            mmu_idx, TARGET_PAGE_SIZE);
+
+    return true;
+}