[MIPS] Implement register_set.{c,h} parts for MIPS

tests/common/register_set.c

Index: tests/common/register_set.c
diff --git a/tests/common/register_set.c b/tests/common/register_set.c
index e9eade72667c3cbbcf2476d56b5c93c6f924dc2f..b11714f8c29375d23daff2e30f8d91e93aeea0ab 100644
--- a/tests/common/register_set.c
+++ b/tests/common/register_set.c
@@ -87,6 +87,40 @@ const struct RegInfo kRegs[] = {
   DEFINE_REG(lr),
   DEFINE_REG(prog_ctr),
   DEFINE_REG(cpsr)
+#elif NACL_ARCH(NACL_BUILD_ARCH) == NACL_mips
+  DEFINE_REG(zero),
+  DEFINE_REG(at),
+  DEFINE_REG(v0),
+  DEFINE_REG(v1),
+  DEFINE_REG(a0),
+  DEFINE_REG(a1),
+  DEFINE_REG(a2),
+  DEFINE_REG(a3),
+  DEFINE_REG(t0),
+  DEFINE_REG(t1),
+  DEFINE_REG(t2),
+  DEFINE_REG(t3),
+  DEFINE_REG(t4),
+  DEFINE_REG(t5),
+  DEFINE_REG(t6),
+  DEFINE_REG(t7),
+  DEFINE_REG(s0),
+  DEFINE_REG(s1),
+  DEFINE_REG(s2),
+  DEFINE_REG(s3),
+  DEFINE_REG(s4),
+  DEFINE_REG(s5),
+  DEFINE_REG(s6),
+  DEFINE_REG(s7),
+  DEFINE_REG(t8),
+  DEFINE_REG(t9),
+  DEFINE_REG(k0),
+  DEFINE_REG(k1),
+  DEFINE_REG(global_ptr),
+  DEFINE_REG(stack_ptr),
+  DEFINE_REG(frame_ptr),
+  DEFINE_REG(return_addr),
+  DEFINE_REG(prog_ctr)
 #else
 # error Unsupported architecture
 #endif
@@ -159,6 +193,9 @@ static void RegsNormalizeFlags(struct NaClSignalContext *regs) {
   regs->flags &= kX86KnownFlagsMask;
 #elif NACL_ARCH(NACL_BUILD_ARCH) == NACL_arm
   regs->cpsr &= REGS_ARM_USER_CPSR_FLAGS_MASK;
+#elif NACL_ARCH(NACL_BUILD_ARCH) == NACL_mips
+  /* No flags field on MIPS. */
+  UNREFERENCED_PARAMETER(regs);
 #endif
 }
 
@@ -181,6 +218,23 @@ void RegsAssertEqual(const struct NaClSignalContext *actual,
    * RegsDump(), so r9 remains listed in kRegs[].
    */
   copy_expected.r9 = copy_actual.r9;
+#elif NACL_ARCH(NACL_BUILD_ARCH) == NACL_mips
+  /*
+   * The registers below are all read-only, so we skip their comparison. We
+   * expect t6 and t7 to hold control flow masks. For t8, which holds TLS
+   * index, we skip comparison. Zero register holds zero always. All of the
+   * above named registers are not settable by untrusted code. We also skip
+   * comparison for k0 and k1 registers because those are registers reserved for
+   * use by interrupt/trap handler and therefore volatile.
+   * However, for debugging purposes we still include those in register dumps
+   * printed by RegsDump(), so they remain listed in kRegs[].
+   */
+  copy_expected.zero = 0;
+  copy_expected.t6 = NACL_CONTROL_FLOW_MASK;
+  copy_expected.t7 = NACL_DATA_FLOW_MASK;
+  copy_expected.t8 = copy_actual.t8;
+  copy_expected.k0 = copy_actual.k0;
+  copy_expected.k1 = copy_actual.k1;
 #endif
 
   for (regnum = 0; regnum < NACL_ARRAY_SIZE(kRegs); regnum++) {
@@ -240,6 +294,26 @@ void RegsUnsetNonCalleeSavedRegisters(struct NaClSignalContext *regs) {
   regs->r12 = 0;
   regs->lr = 0;
   regs->cpsr = 0;
+#elif NACL_ARCH(NACL_BUILD_ARCH) == NACL_mips
+  regs->zero = 0;
+  regs->at = 0;
+  regs->v0 = 0;
+  regs->v1 = 0;
+  regs->a0 = 0;
+  regs->a1 = 0;
+  regs->a2 = 0;
+  regs->a3 = 0;
+  regs->t0 = 0;
+  regs->t1 = 0;
+  regs->t2 = 0;
+  regs->t3 = 0;
+  regs->t4 = 0;
+  regs->t5 = 0;
+  regs->t9 = 0;
+  regs->k0 = 0;
+  regs->k1 = 0;
+  regs->global_ptr  = 0;
+  regs->return_addr = 0;
 #else
 # error Unsupported architecture
 #endif
@@ -264,6 +338,12 @@ uintptr_t RegsGetArg1(const struct NaClSignalContext *regs) {
   return regs->r0;
 }
 
+#elif NACL_ARCH(NACL_BUILD_ARCH) == NACL_mips
+
+uintptr_t RegsGetArg1(const struct NaClSignalContext *regs) {
+  return regs->a0;
+}
+
 #else
 # error Unsupported architecture
 #endif