mips32-nemu: add basic cte

am/arch/mips32-nemu/include/arch.h

@@ -1,22 +1,28 @@
 #ifndef __ARCH_H__
 #define __ARCH_H__
 
+#include <am.h>
+
+#define PMEM_SIZE (128 * 1024 * 1024)
+#define PGSIZE    4096
+
 struct _Context {
-  uint32_t at,
-  v0,v1,
-  a0,a1,a2,a3,
-  t0,t1,t2,t3,t4,t5,t6,t7,t8,t9,
-  s0,s1,s2,s3,s4,s5,s6,s7,
-  k0,k1,
-  gp,sp,fp,ra;
+  struct _Protect *prot;
+  uint32_t gpr[31];
+  uint32_t lo, hi;
+  uint32_t cause, status, epc;
 };
 
+#define GPR1 gpr[4]
+#define GPR2 gpr[5]
+#define GPR3 gpr[6]
+#define GPR4 gpr[7]
+#define GPRx gpr[2]
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-//static inline void _ioe_init() { }
-
 #ifdef __cplusplus
 }
 #endif

am/arch/mips32-nemu/src/cte.c

@@ -0,0 +1,64 @@
+#include <am.h>
+#include <mips32.h>
+#include <klib.h>
+
+static _Context* (*user_handler)(_Event, _Context*) = NULL;
+
+void get_cur_as(_Context *c);
+void _switch(_Context *c);
+
+_Context* irq_handle(_Context *c) {
+//  get_cur_as(c);
+
+  _Context *next = c;
+  if (user_handler) {
+    _Event ev = {0};
+    uint32_t ex_code = (c->cause >> 2) & 0x1f;
+    uint32_t syscall_instr;
+    switch (ex_code) {
+      case 0: ev.event = _EVENT_IRQ_TIMER; break;
+      case 8: 
+        syscall_instr = *(uint32_t *)(c->epc);
+        ev.event = ((syscall_instr >> 6) == 1) ? _EVENT_YIELD : _EVENT_SYSCALL;
+        c->epc += 4;
+        break;
+      default: ev.event = _EVENT_ERROR; break;
+    }
+
+    next = user_handler(ev, c);
+    if (next == NULL) {
+      next = c;
+    }
+  }
+
+//  _switch(next);
+
+  return next;
+}
+
+extern void asm_trap(void);
+
+#define EX_ENTRY 0x180
+
+int _cte_init(_Context*(*handler)(_Event, _Context*)) {
+  // initialize exception entry
+  uint32_t *p = (uint32_t *)EX_ENTRY;
+  *p = 0x08000000 | (((uint32_t)asm_trap >> 2) & 0x3ffffff);
+
+  // register event handler
+  user_handler = handler;
+
+  return 0;
+}
+
+_Context *_kcontext(_Area stack, void (*entry)(void *), void *arg) {
+  return NULL;
+}
+
+void _yield() {
+  asm volatile("syscall 1");
+}
+
+int _istatus(int enable) {
+  return 0;
+}

am/arch/mips32-nemu/src/trap.S

@@ -0,0 +1,61 @@
+
+#define concat_temp(x, y) x ## y
+#define concat(x, y) concat_temp(x, y)
+
+#define regs(X) \
+      X( 1) X( 2) X( 3) X( 4) X( 5) X( 6) X( 7) X( 8) X( 9) \
+X(10) X(11) X(12) X(13) X(14) X(15) X(16) X(17) X(18) X(19) \
+X(20) X(21) X(22) X(23) X(24) X(25) X(26) X(27) X(28)       \
+X(30) X(31)
+
+#define CONTEXT_SIZE ((31 + 6) * 4)
+#define OFFSET_SP     (29 * 4)
+#define OFFSET_LO     (32 * 4)
+#define OFFSET_HI     (33 * 4)
+#define OFFSET_CAUSE  (34 * 4)
+#define OFFSET_STATUS (35 * 4)
+#define OFFSET_EPC    (36 * 4)
+
+#define CP0_STATUS 12
+#define CP0_CAUSE  13
+#define CP0_EPC    14
+
+#define push(n) sw $n, (n * 4)($sp);
+#define pop(n)  lw $n, (n * 4)($sp);
+
+.set noat
+.globl asm_trap
+asm_trap:
+  move $k0, $sp
+  addiu $sp, $sp, -CONTEXT_SIZE
+
+  regs(push)
+  sw $k0, OFFSET_SP($sp)
+  mflo $t0
+  mfhi $t1
+  mfc0 $t2, $CP0_CAUSE
+  mfc0 $t3, $CP0_STATUS
+  mfc0 $t4, $CP0_EPC
+  sw $t0, OFFSET_LO($sp)
+  sw $t1, OFFSET_HI($sp)
+  sw $t2, OFFSET_CAUSE($sp)
+  sw $t3, OFFSET_STATUS($sp)
+  sw $t4, OFFSET_EPC($sp)
+
+  move $a0, $sp
+  jal irq_handle
+
+  lw $t0, OFFSET_LO($sp)
+  lw $t1, OFFSET_HI($sp)
+  lw $t2, OFFSET_CAUSE($sp)
+  lw $t3, OFFSET_STATUS($sp)
+  lw $t4, OFFSET_EPC($sp)
+  mtlo $t0
+  mthi $t1
+  mtc0 $t2, $CP0_CAUSE
+  mtc0 $t3, $CP0_STATUS
+  mtc0 $t4, $CP0_EPC
+
+  regs(pop)
+
+  eret

am/arch/mips32-nemu/src/vme.c

@@ -0,0 +1,45 @@
+#include <mips32.h>
+#include <klib.h>
+
+#define PG_ALIGN __attribute((aligned(PGSIZE)))
+
+static void* (*pgalloc_usr)(size_t);
+static void (*pgfree_usr)(void*);
+
+_Area segments[] = {      // Kernel memory mappings
+  {.start = (void*)0,          .end = (void*)PMEM_SIZE}
+};
+
+#define NR_KSEG_MAP (sizeof(segments) / sizeof(segments[0]))
+
+int _vme_init(void* (*pgalloc_f)(size_t), void (*pgfree_f)(void*)) {
+  pgalloc_usr = pgalloc_f;
+  pgfree_usr = pgfree_f;
+
+  return 0;
+}
+
+int _protect(_Protect *p) {
+  return 0;
+}
+
+void _unprotect(_Protect *p) {
+}
+
+static _Protect *cur_as = NULL;
+void get_cur_as(_Context *c) {
+  c->prot = cur_as;
+}
+
+void _switch(_Context *c) {
+  assert(0);
+  cur_as = c->prot;
+}
+
+int _map(_Protect *p, void *va, void *pa, int mode) {
+  return 0;
+}
+
+_Context *_ucontext(_Protect *p, _Area ustack, _Area kstack, void *entry, void *args) {
+  return NULL;
+}