MIPS: The new ABI should be allowed to use r8 and r9 for syscalls.

lss/linux_syscall_support.h

 /* Copyright (c) 2005-2011, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 2353 matching lines @@
       {
         register int   __flags __asm__("r0") = flags;
         register void *__stack __asm__("r1") = child_stack;
         register void *__ptid  __asm__("r2") = parent_tidptr;
         register void *__tls   __asm__("r3") = newtls;
         register int  *__ctid  __asm__("r4") = child_tidptr;
         __asm__ __volatile__(/* if (fn == NULL || child_stack == NULL)
                               *   return -EINVAL;
                               */
 #ifdef __thumb2__
-                             "push  {r7}\n"
+                             "push  {r7}\n"
 #endif
                              "cmp   %2,#0\n"
                              "it    ne\n"
                              "cmpne %3,#0\n"
                              "it    eq\n"
                              "moveq %0,%1\n"
                              "beq   1f\n"
 
                              /* Push "arg" and "fn" onto the stack that will be
                               * used by the child.
@@ skipping 37 matching lines @@
                              "mov   lr,pc\n"
                              "ldr   pc,[sp]\n"
                            #endif
 
                              /* Call _exit(%r0).
                               */
                              "mov r7, %10\n"
                              "swi 0x0\n"
                            "1:\n"
 #ifdef __thumb2__
-                             "pop {r7}"
+                             "pop {r7}"
 #endif
                              : "=r" (__res)
                              : "i"(-EINVAL),
                                "r"(fn), "r"(__stack), "r"(__flags), "r"(arg),
                                "r"(__ptid), "r"(__tls), "r"(__ctid),
                                "i"(__NR_clone), "i"(__NR_exit)
 #ifdef __thumb2__
-                             : "cc", "lr", "memory");
+                             : "cc", "lr", "memory");
 #else
                              : "cc", "r7", "lr", "memory");
 #endif
       }
       LSS_RETURN(int, __res);
     }
   #elif defined(__aarch64__)
     /* Most definitions of _syscallX() neglect to mark "memory" as being
      * clobbered. This causes problems with compilers, that do a better job
      * at optimizing across __asm__ calls.
@@ skipping 108 matching lines @@
                                "i"(__NR_clone), "i"(__NR_exit)
                              : "cc", "x8", "memory");
       }
       LSS_RETURN(int, __res);
     }
   #elif defined(__mips__)
     #undef LSS_REG
     #define LSS_REG(r,a) register unsigned long __r##r __asm__("$"#r) =       \
                                  (unsigned long)(a)
     #undef  LSS_BODY
+    #undef LSS_SYSCALL_CLOBBERS
+    #if _MIPS_SIM == _MIPS_SIM_ABI32
+    #define LSS_SYSCALL_CLOBBERS "$1", "$3", "$8", "$9", "$10",               \
+                                 "$11", "$12", "$13", "$14", "$15",           \
+                                 "$24", "$25", "hi", "lo", "memory"
+    #else
+    #define LSS_SYSCALL_CLOBBERS "$1", "$3", "$10", "$11", "$12",             \
+                                 "$13", "$14", "$15", "$24", "$25",           \
+                                 "hi", "lo", "memory"
+    #endif
     #define LSS_BODY(type,name,r7,...)                                        \
           register unsigned long __v0 __asm__("$2") = __NR_##name;            \
           __asm__ __volatile__ ("syscall\n"                                   \
                                 : "+r"(__v0), r7 (__r7)                       \
                                 : "0"(__v0), ##__VA_ARGS__                    \
-                                : "$8", "$9", "$10", "$11", "$12",            \
-                                  "$13", "$14", "$15", "$24", "$25",          \
-                                  "memory");                                  \
+                                : LSS_SYSCALL_CLOBBERS);                      \
           LSS_RETURN(type, __v0, __r7)
     #undef _syscall0
     #define _syscall0(type, name)                                             \
       type LSS_NAME(name)(void) {                                             \
         register unsigned long __r7 __asm__("$7");                            \
         LSS_BODY(type, name, "=r");                                           \
       }
     #undef _syscall1
     #define _syscall1(type, name, type1, arg1)                                \
       type LSS_NAME(name)(type1 arg1) {                                       \
@@ skipping 1425 matching lines @@
 # pragma pop_macro("fstat64")
 # pragma pop_macro("lstat64")
 #endif
 
 #if defined(__cplusplus) && !defined(SYS_CPLUSPLUS)
 }
 #endif
 
 #endif
 #endif