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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.
This commit is contained in:
Richard Henderson 2014-05-22 16:57:20 -04:00
parent 11a28aee60
commit 1670e207c5
2 changed files with 22 additions and 24 deletions
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10
ChangeLog
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@ -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.

36
sysdeps/unix/sysv/linux/aarch64/sysdep.h
View File

@ -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