riscv64-noop: use independent vme.c and trap.S apart from riscv64-nemu

am/arch/riscv64-noop.mk

@@ -4,9 +4,9 @@ AM_SRCS := $(ISA)/noop/trm.c \
            $(ISA)/noop/uartlite.c \
            $(ISA)/noop/perf.c \
            $(ISA)/noop/cte.c \
-           $(ISA)/nemu/trap.S \
+           $(ISA)/noop/trap.S \
            $(ISA)/noop/instr.c \
-           $(ISA)/nemu/vme.c \
+           $(ISA)/noop/vme.c \
            nemu-common/ioe.c \
            $(ISA)/noop/input.c \
            nemu-common/nemu-timer.c \

am/src/riscv64/noop/cte.c

@@ -49,7 +49,7 @@ _Context* __am_irq_handle(_Context *c) {
     }
   }
 
-//  __am__switch(next);
+  __am_switch(next);
 
   return next;
 }
@@ -73,7 +73,7 @@ _Context *_kcontext(_Area stack, void (*entry)(void *), void *arg) {
   _Context *c = (_Context*)stack.end - 1;
 
   c->mepc = (uintptr_t)entry;
-  c->mstatus = 0x000c0180;
+  c->mstatus = 0x000c1880;
   return c;
 }
 

am/src/riscv64/noop/trap.S

+// unmodified for cputest
+
+#define concat_temp(x, y) x ## y
+#define concat(x, y) concat_temp(x, y)
+#define MAP(c, f) c(f)
+
+#define REGS(f) \
+      f( 1)       f( 3) f( 4) f( 5) f( 6) f( 7) f( 8) f( 9) \
+f(10) f(11) f(12) f(13) f(14) f(15) f(16) f(17) f(18) f(19) \
+f(20) f(21) f(22) f(23) f(24) f(25) f(26) f(27) f(28) f(29) \
+f(30) f(31)
+
+#define PUSH(n) sd concat(x, n), (n * 8)(sp);
+#define POP(n)  ld concat(x, n), (n * 8)(sp);
+
+#define CONTEXT_SIZE ((31 + 4) * 8)
+#define OFFSET_SP     ( 2 * 8)
+#define OFFSET_CAUSE  (32 * 8)
+#define OFFSET_STATUS (33 * 8)
+#define OFFSET_EPC    (34 * 8)
+
+.globl __am_asm_trap
+__am_asm_trap:
+  addi sp, sp, -CONTEXT_SIZE
+
+  MAP(REGS, PUSH)
+
+  mv t0, sp
+  addi t0, t0, CONTEXT_SIZE
+  sd t0, OFFSET_SP(sp)
+
+  csrr t0, mcause
+  csrr t1, mstatus
+  csrr t2, mepc
+
+  sd t0, OFFSET_CAUSE(sp)
+  sd t1, OFFSET_STATUS(sp)
+  sd t2, OFFSET_EPC(sp)
+
+  mv a0, sp
+  jal __am_irq_handle
+
+  mv sp, a0
+
+  ld t1, OFFSET_STATUS(sp)
+  ld t2, OFFSET_EPC(sp)
+  csrw mstatus, t1
+  csrw mepc, t2
+
+  MAP(REGS, POP)
+
+  addi sp, sp, CONTEXT_SIZE
+
+  mret

am/src/riscv64/noop/vme.c

+#include <riscv64.h>
+#include <nemu.h>
+#include <klib.h>
+
+#define PG_ALIGN __attribute((aligned(PGSIZE)))
+
+static _AddressSpace kas; // Kernel address space
+static void* (*pgalloc_usr)(size_t) = NULL;
+static void (*pgfree_usr)(void*) = NULL;
+static int vme_enable = 0;
+
+static _Area segments[] = {      // Kernel memory mappings
+  {.start = (void*)0x80000000u, .end = (void*)(0x80000000u + 0x3000000)}, //PMEM_SIZE)},
+  {.start = (void*)0x40600000u, .end = (void*)(0x40600000u + 0x1000)},   // uart
+  {.start = (void*)0x40700000u, .end = (void*)(0x40700000u + 0x1000)},   // clint/timer
+  {.start = (void*)0x40000000u, .end = (void*)(0x40000000u + 0x400000)}, // vmem
+  {.start = (void*)0x40800000u, .end = (void*)(0x40800000u + 0x1000)}    // vga ctrl
+};
+
+#define NR_KSEG_MAP (sizeof(segments) / sizeof(segments[0]))
+
+static inline void set_satp(void *pdir) {
+  uintptr_t mode = 8ull << 60;
+  asm volatile("csrw satp, %0" : : "r"(mode | PN(pdir)));
+}
+
+int _vme_init(void* (*pgalloc_f)(size_t), void (*pgfree_f)(void*)) {
+  pgalloc_usr = pgalloc_f;
+  pgfree_usr = pgfree_f;
+
+  kas.ptr = pgalloc_f(1);
+  // make all PTEs invalid
+  memset(kas.ptr, 0, PGSIZE);
+
+  int i;
+  for (i = 0; i < NR_KSEG_MAP; i ++) {
+    void *va = segments[i].start;
+    for (; va < segments[i].end; va += PGSIZE) {
+      _map(&kas, va, va, 0);
+    }
+  }
+
+  set_satp(kas.ptr);
+  vme_enable = 1;
+
+  return 0;
+}
+
+int _protect(_AddressSpace *as) {
+  PTE *updir = (PTE *)(pgalloc_usr(1));
+  as->ptr = updir;
+  // map kernel space
+  memcpy(updir, kas.ptr, PGSIZE);
+
+  return 0;
+}
+
+void _unprotect(_AddressSpace *as) {
+}
+
+static _AddressSpace *cur_as = NULL;
+void __am_get_cur_as(_Context *c) {
+  c->as = cur_as;
+}
+
+void __am_switch(_Context *c) {
+  if (vme_enable) {
+    set_satp(c->as->ptr);
+    cur_as = c->as;
+  }
+}
+
+int _map(_AddressSpace *as, void *va, void *pa, int prot) {
+  PTE *pg_base = as->ptr;
+  PTE *pte;
+  int level;
+  for (level = PTW_LEVEL - 1; level >= 0; level --) {
+    pte = &pg_base[VPNi((uintptr_t)va, level)];
+    pg_base = (PTE *)PTE_ADDR(*pte);
+    if (level != 0 && !(*pte & PTE_V)) {
+      pg_base = pgalloc_usr(1);
+      *pte = PTE_V | (PN(pg_base) << 10);
+    }
+  }
+
+  if (!(*pte & PTE_V)) {
+    *pte = PTE_V | PTE_R | PTE_W | PTE_X | (PN(pa) << 10);
+  }
+
+  return 0;
+}
+
+_Context *_ucontext(_AddressSpace *as, _Area ustack, _Area kstack, void *entry, void *args) {
+  _Context *c = (_Context*)ustack.end - 1;
+  c->gpr[10] = c->gpr[11] = 0;
+
+  c->as = as;
+  c->mepc = (uintptr_t)entry;
+  c->mstatus = 0x000c1880;
+  return c;
+}