aarch64: Rely on syscalls preserving registers

In several cases we've had asm routines rely on syscalls not clobbering
call-clobbered registers, and that's now deemed ABI.  So take advantage
of this in the INLINE_SYSCALL path as well.

Shrinks libc.so by about 1k.

diff --git a/ChangeLog b/ChangeLog
index 8ea6ef9a2d764a624b45461d211345390b4ff2b4..8e06a7e1c37102f916ceee947688c8da0e494312 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,15 @@
 2014-05-29  Richard Henderson  <rth@twiddle.net>
 
+       * sysdeps/unix/sysv/linux/aarch64/sysdep.h (INTERNAL_VSYSCALL_NCS):
+       Remove comma before expanding ASM_ARGS_##nr.
+       (INTERNAL_SYSCALL_RAW): Make _sys_result signed, instead of casting.
+       Make _x0 a strict output; make _x8 a strict input; adjust expansion
+       of ASM_ARGS_##nr.
+       (CLOBBER_ARGS_0, CLOBBER_ARGS_1, CLOBBER_ARGS_2): Remove.
+       (CLOBBER_ARGS_3, CLOBBER_ARGS_4, CLOBBER_ARGS_5): Remove.
+       (CLOBBER_ARGS_6, CLOBBER_ARGS_7): Remove.
+       (ASM_ARGS_1): Add leading comma.
+
        * sysdeps/unix/sysv/linux/aarch64/sysdep.h [NOT_IN_libc]
        (SYSCALL_ERROR_HANDLER): Use tpidr_el0 instead of a call
        to __errno_location.

diff --git a/sysdeps/unix/sysv/linux/aarch64/sysdep.h b/sysdeps/unix/sysv/linux/aarch64/sysdep.h
index 8cce986b008f9ea472bbd5f50b39f741fbe48768..4686599a7efd2ec189a72dc70d96e2f5b0c9ec74 100644 (file)
--- a/sysdeps/unix/sysv/linux/aarch64/sysdep.h
+++ b/sysdeps/unix/sysv/linux/aarch64/sysdep.h
@@ -231,7 +231,7 @@
     LOAD_ARGS_##nr (args)                                      \
     asm volatile ("blr %1"                                     \
                  : "=r" (_x0)                                  \
-                 : "r" (funcptr), ASM_ARGS_##nr                \
+                 : "r" (funcptr) ASM_ARGS_##nr                 \
                  : "x30", "memory");                           \
     (long) _x0;                                                        \
   })
@@ -254,17 +254,15 @@
 
 # undef INTERNAL_SYSCALL_RAW
 # define INTERNAL_SYSCALL_RAW(name, err, nr, args...)          \
-  ({ unsigned long _sys_result;                                        \
+  ({ long _sys_result;                                         \
      {                                                         \
        LOAD_ARGS_##nr (args)                                   \
        register long _x8 asm ("x8") = (name);                  \
        asm volatile ("svc      0       // syscall " # name     \
-                    : "+r" (_x0), "+r" (_x8)                   \
-                    : ASM_ARGS_##nr                            \
-                    : "memory", CLOBBER_ARGS_##nr);            \
+                    : "=r" (_x0) : "r"(_x8) ASM_ARGS_##nr : "memory"); \
        _sys_result = _x0;                                      \
      }                                                         \
-     (long) _sys_result; })
+     _sys_result; })
 
 # undef INTERNAL_SYSCALL
 # define INTERNAL_SYSCALL(name, err, nr, args...)              \
@@ -281,54 +279,44 @@
 # undef INTERNAL_SYSCALL_ERRNO
 # define INTERNAL_SYSCALL_ERRNO(val, err)      (-(val))
 
-# define CLOBBER_ARGS_0       CLOBBER_ARGS_1
-# define CLOBBER_ARGS_1 "x1", CLOBBER_ARGS_2
-# define CLOBBER_ARGS_2 "x2", CLOBBER_ARGS_3
-# define CLOBBER_ARGS_3 "x3", CLOBBER_ARGS_4
-# define CLOBBER_ARGS_4 "x4", CLOBBER_ARGS_5
-# define CLOBBER_ARGS_5 "x5", CLOBBER_ARGS_6
-# define CLOBBER_ARGS_6 "x6", CLOBBER_ARGS_7
-# define CLOBBER_ARGS_7 \
-  "x7", "x9", "x10", "x11", "x12", "x13", "x14", "x15", "x16", "x17", "x18"
-
 # define LOAD_ARGS_0()                         \
   register long _x0 asm ("x0");
-
-# define ASM_ARGS_0
 # define LOAD_ARGS_1(x0)                       \
   long _x0tmp = (long) (x0);                   \
   LOAD_ARGS_0 ()                               \
   _x0 = _x0tmp;
-# define ASM_ARGS_1    "r" (_x0)
 # define LOAD_ARGS_2(x0, x1)                   \
   long _x1tmp = (long) (x1);                   \
   LOAD_ARGS_1 (x0)                             \
   register long _x1 asm ("x1") = _x1tmp;
-# define ASM_ARGS_2    ASM_ARGS_1, "r" (_x1)
 # define LOAD_ARGS_3(x0, x1, x2)               \
   long _x2tmp = (long) (x2);                   \
   LOAD_ARGS_2 (x0, x1)                         \
   register long _x2 asm ("x2") = _x2tmp;
-# define ASM_ARGS_3    ASM_ARGS_2, "r" (_x2)
 # define LOAD_ARGS_4(x0, x1, x2, x3)           \
   long _x3tmp = (long) (x3);                   \
   LOAD_ARGS_3 (x0, x1, x2)                     \
   register long _x3 asm ("x3") = _x3tmp;
-# define ASM_ARGS_4    ASM_ARGS_3, "r" (_x3)
 # define LOAD_ARGS_5(x0, x1, x2, x3, x4)       \
   long _x4tmp = (long) (x4);                   \
   LOAD_ARGS_4 (x0, x1, x2, x3)                 \
   register long _x4 asm ("x4") = _x4tmp;
-# define ASM_ARGS_5    ASM_ARGS_4, "r" (_x4)
 # define LOAD_ARGS_6(x0, x1, x2, x3, x4, x5)   \
   long _x5tmp = (long) (x5);                   \
   LOAD_ARGS_5 (x0, x1, x2, x3, x4)             \
   register long _x5 asm ("x5") = _x5tmp;
-# define ASM_ARGS_6    ASM_ARGS_5, "r" (_x5)
 # define LOAD_ARGS_7(x0, x1, x2, x3, x4, x5, x6)\
   long _x6tmp = (long) (x6);                   \
   LOAD_ARGS_6 (x0, x1, x2, x3, x4, x5)         \
   register long _x6 asm ("x6") = _x6tmp;
+
+# define ASM_ARGS_0
+# define ASM_ARGS_1    , "r" (_x0)
+# define ASM_ARGS_2    ASM_ARGS_1, "r" (_x1)
+# define ASM_ARGS_3    ASM_ARGS_2, "r" (_x2)
+# define ASM_ARGS_4    ASM_ARGS_3, "r" (_x3)
+# define ASM_ARGS_5    ASM_ARGS_4, "r" (_x4)
+# define ASM_ARGS_6    ASM_ARGS_5, "r" (_x5)
 # define ASM_ARGS_7    ASM_ARGS_6, "r" (_x6)
 
 # undef INTERNAL_SYSCALL_NCS