*-nemu: refactor phyiscal address space for vme

am/src/nemu/common/trm.c

@@ -1,13 +1,13 @@
 #include <am.h>
+#include <nemu.h>
 #include <klib-macros.h>
 
 // common part of TMR
 
 extern char _heap_start;
-extern char _heap_end;
 int main(const char *args);
 
-_Area _heap = RANGE(&_heap_start, &_heap_end);
+_Area _heap = RANGE(&_heap_start, &_pmem_end);
 
 void _trm_init() {
   extern const char __am_mainargs;

am/src/nemu/include/nemu.h

@@ -33,10 +33,16 @@
 # define FB_ADDR      0xa0000000
 #endif
 
-#define PMEM_SIZE (128 * 1024 * 1024)
 #define PGSIZE    4096
 
 #define MMIO_BASE 0xa0000000
 #define MMIO_SIZE 0x10000000
 
+extern char _pmem_start, _pmem_end;
+
+#define NEMU_PADDR_SPACE \
+  RANGE(&_pmem_start, &_pmem_end), \
+  RANGE(0xa0000000, 0xa0000000 + 0x80000), /* vmem */ \
+  RANGE(0xa1000000, 0xa1000000 + 0x1000)   /* serial, rtc, screen, keyboard */
+
 #endif

am/src/nemu/isa/mips/boot/loader.ld

@@ -1,3 +1,5 @@
+pmem_base = 0x80000000;
+
 MEMORY {
   ram (rwxa) : ORIGIN = 0x80100000, LENGTH = 128M
 }

am/src/nemu/isa/riscv/boot/loader.ld

@@ -1,3 +1,5 @@
+pmem_base = 0x80000000;
+
 MEMORY {
   ram (rwxa) : ORIGIN = 0x80100000, LENGTH = 128M
 }

am/src/nemu/isa/riscv/boot/loader64.ld

@@ -1,3 +1,5 @@
+pmem_base = 0x80000000;
+
 MEMORY {
   ram (rwxa) : ORIGIN = 0x80000000, LENGTH = 128M
 }

am/src/nemu/isa/riscv/vme.c

@@ -7,9 +7,7 @@ static void (*pgfree_usr)(void*) = NULL;
 static int vme_enable = 0;
 
 static const _Area segments[] = {      // Kernel memory mappings
-  RANGE(0x80000000, 0x80000000 + PMEM_SIZE),
-  RANGE(0xa1000000, 0xa1000000 + 0x1000),  // serial, rtc, screen, keyboard
-  RANGE(0xa0000000, 0xa0000000 + 0x80000), // vmem
+  NEMU_PADDR_SPACE,
 #if __riscv_xlen == 64
   RANGE(0xa2000000, 0xa2000000 + 0x10000), // clint
 #endif
@@ -85,10 +83,11 @@ void _map(_AddressSpace *as, void *va, void *pa, int prot) {
   PTE *pg_base = as->ptr;
   PTE *pte;
   int level;
-  for (level = PTW_CONFIG.ptw_level - 1; level >= 0; level --) {
+  for (level = PTW_CONFIG.ptw_level - 1; ; level --) {
     pte = &pg_base[VPNi(PTW_CONFIG, (uintptr_t)va, level)];
     pg_base = (PTE *)PTE_ADDR(*pte);
-    if (level != 0 && !(*pte & PTE_V)) {
+    if (level == 0) break;
+    if (!(*pte & PTE_V)) {
       pg_base = pgalloc_usr(PGSIZE);
       *pte = PTE_V | (PN(pg_base) << 10);
     }

am/src/nemu/isa/x86/boot/loader.ld

@@ -1,3 +1,5 @@
+pmem_base = 0x0;
+
 MEMORY {
   ram (rwxa) : ORIGIN = 0x100000, LENGTH = 128M
 }

am/src/nemu/isa/x86/vme.c

@@ -25,8 +25,7 @@ static void (*pgfree_usr)(void*) = NULL;
 static int vme_enable = 0;
 
 static _Area segments[] = {      // Kernel memory mappings
-  RANGE(0, PMEM_SIZE),
-  RANGE(MMIO_BASE, MMIO_BASE + MMIO_SIZE),
+  NEMU_PADDR_SPACE,
 };
 
 #define USER_SPACE RANGE(0x40000000, 0xc0000000)

am/src/nemu/ldscript/section.ld

@@ -28,5 +28,6 @@ SECTIONS {
   end = .;
   _end = .;
   _heap_start = ALIGN(0x1000);
-  _heap_end = ORIGIN(ram) + LENGTH(ram);
+  _pmem_start = pmem_base;
+  _pmem_end = _pmem_start + LENGTH(ram);
 }