[MIPS] Add seccomp bpf support

sandbox/linux/seccomp-bpf/syscall_iterator_unittest.cc

Index: sandbox/linux/seccomp-bpf/syscall_iterator_unittest.cc
diff --git a/sandbox/linux/seccomp-bpf/syscall_iterator_unittest.cc b/sandbox/linux/seccomp-bpf/syscall_iterator_unittest.cc
index 08a857a2e2933ad03eb29406874f0e48bb99d5ef..bd03b423892ed850245fe89b8da965a3eb25c2b4 100644
--- a/sandbox/linux/seccomp-bpf/syscall_iterator_unittest.cc
+++ b/sandbox/linux/seccomp-bpf/syscall_iterator_unittest.cc
@@ -17,8 +17,13 @@ SANDBOX_TEST(SyscallIterator, Monotonous) {
     uint32_t next = iter.Next();
 
     if (!invalid_only) {
+#if defined(__mips__) && (_MIPS_SIM == _MIPS_SIM_ABI32)
+      // The iterator should start at 4000 for MIPS O32 ABI
+      SANDBOX_ASSERT(next == 4000);

[jln (very slow on Chromium), 2014/05/02 20:42:04]

This adds no value, we need to re-work these tests to make them compatible with
MIN_SYSCALL > 0.

[nedeljko, 2014/05/07 15:40:05]

Done.

+#else
       // The iterator should start at 0.
       SANDBOX_ASSERT(next == 0);

[jln (very slow on Chromium), 2014/05/02 20:42:04]

This should still hold on MIPS.

[nedeljko, 2014/05/07 15:40:05]

Done.

+#endif
     }
     for (uint32_t last = next; !iter.Done(); last = next) {
       next = iter.Next();
@@ -35,9 +40,14 @@ SANDBOX_TEST(SyscallIterator, PublicSyscallRange) {
 
   // The iterator should cover the public syscall range
   // MIN_SYSCALL..MAX_PUBLIC_SYSCALL, without skipping syscalls.
-  // We're assuming MIN_SYSCALL == 0 for all architectures,
-  // this is currently valid for Intel and ARM EABI.
+  // We're assuming MIN_SYSCALL == 0 for all architectures
+  // (this is currently valid for Intel and ARM EABI), except for
+  // Mips O32 ABI for which MIN_SYSCALL == 4000 .
+#if defined(__mips__) && (_MIPS_SIM == _MIPS_SIM_ABI32)
+  SANDBOX_ASSERT(MIN_SYSCALL == 4000);
+#else
   SANDBOX_ASSERT(MIN_SYSCALL == 0);
+#endif
   SANDBOX_ASSERT(next == MIN_SYSCALL);
   for (uint32_t last = next; next < MAX_PUBLIC_SYSCALL + 1; last = next) {
     SANDBOX_ASSERT((next = iter.Next()) == last + 1);
@@ -107,10 +117,15 @@ SANDBOX_TEST(SyscallIterator, InvalidOnly) {
   bool invalid_only = true;
   SyscallIterator iter(invalid_only);
   uint32_t next = iter.Next();
-  // We're assuming MIN_SYSCALL == 0 for all architectures,
-  // this is currently valid for Intel and ARM EABI.
+  // We're assuming MIN_SYSCALL == 0 for all architectures
+  // (this is currently valid for Intel and ARM EABI), except
+  // for Mips O32 ABI for which MIN_SYSCALL == 4000.
   // First invalid syscall should then be |MAX_PUBLIC_SYSCALL + 1|.
+#if defined(__mips__) && (_MIPS_SIM == _MIPS_SIM_ABI32)
+  SANDBOX_ASSERT(MIN_SYSCALL == 4000);
+#else
   SANDBOX_ASSERT(MIN_SYSCALL == 0);
+#endif
   SANDBOX_ASSERT(next == MAX_PUBLIC_SYSCALL + 1);
 
 #if defined(__arm__)