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git://sourceware.org/git/glibc.git
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1670e207c5
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.
369 lines
12 KiB
C
369 lines
12 KiB
C
/* Copyright (C) 2005-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _LINUX_AARCH64_SYSDEP_H
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#define _LINUX_AARCH64_SYSDEP_H 1
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#include <sysdeps/unix/sysdep.h>
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#include <sysdeps/aarch64/sysdep.h>
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#include <sysdeps/unix/sysv/linux/generic/sysdep.h>
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/* Defines RTLD_PRIVATE_ERRNO and USE_DL_SYSINFO. */
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#include <dl-sysdep.h>
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#include <tls.h>
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/* In order to get __set_errno() definition in INLINE_SYSCALL. */
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#ifndef __ASSEMBLER__
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#include <errno.h>
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#endif
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/* For Linux we can use the system call table in the header file
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/usr/include/asm/unistd.h
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of the kernel. But these symbols do not follow the SYS_* syntax
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so we have to redefine the `SYS_ify' macro here. */
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#undef SYS_ify
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#define SYS_ify(syscall_name) (__NR_##syscall_name)
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#ifdef __ASSEMBLER__
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/* Linux uses a negative return value to indicate syscall errors,
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unlike most Unices, which use the condition codes' carry flag.
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Since version 2.1 the return value of a system call might be
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negative even if the call succeeded. E.g., the `lseek' system call
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might return a large offset. Therefore we must not anymore test
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for < 0, but test for a real error by making sure the value in R0
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is a real error number. Linus said he will make sure the no syscall
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returns a value in -1 .. -4095 as a valid result so we can safely
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test with -4095. */
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# undef PSEUDO
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# define PSEUDO(name, syscall_name, args) \
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.text; \
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ENTRY (name); \
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DO_CALL (syscall_name, args); \
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cmn x0, #4095; \
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b.cs .Lsyscall_error;
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/* Notice the use of 'RET' instead of 'ret' the assembler is case
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insensitive and eglibc already uses the preprocessor symbol 'ret'
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so we use the upper case 'RET' to force through a ret instruction
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to the assembler */
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# define PSEUDO_RET \
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RET;
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# undef ret
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# define ret PSEUDO_RET
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# undef PSEUDO_END
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# define PSEUDO_END(name) \
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SYSCALL_ERROR_HANDLER \
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END (name)
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# undef PSEUDO_NOERRNO
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# define PSEUDO_NOERRNO(name, syscall_name, args) \
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.text; \
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ENTRY (name); \
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DO_CALL (syscall_name, args);
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/* Notice the use of 'RET' instead of 'ret' the assembler is case
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insensitive and eglibc already uses the preprocessor symbol 'ret'
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so we use the upper case 'RET' to force through a ret instruction
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to the assembler */
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# define PSEUDO_RET_NOERRNO \
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RET;
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# undef ret_NOERRNO
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# define ret_NOERRNO PSEUDO_RET_NOERRNO
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# undef PSEUDO_END_NOERRNO
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# define PSEUDO_END_NOERRNO(name) \
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END (name)
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/* The function has to return the error code. */
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# undef PSEUDO_ERRVAL
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# define PSEUDO_ERRVAL(name, syscall_name, args) \
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.text; \
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ENTRY (name) \
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DO_CALL (syscall_name, args); \
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neg x0, x0
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# undef PSEUDO_END_ERRVAL
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# define PSEUDO_END_ERRVAL(name) \
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END (name)
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# define ret_ERRVAL PSEUDO_RET_NOERRNO
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# if NOT_IN_libc
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# define SYSCALL_ERROR .Lsyscall_error
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# if RTLD_PRIVATE_ERRNO
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# define SYSCALL_ERROR_HANDLER \
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.Lsyscall_error: \
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adrp x1, C_SYMBOL_NAME(rtld_errno); \
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neg w0, w0; \
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str w0, [x1, :lo12:C_SYMBOL_NAME(rtld_errno)]; \
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mov x0, -1; \
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RET;
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# else
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# define SYSCALL_ERROR_HANDLER \
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.Lsyscall_error: \
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adrp x1, :gottprel:errno; \
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neg w2, w0; \
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ldr x1, [x1, :gottprel_lo12:errno]; \
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mrs x3, tpidr_el0; \
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mov x0, -1; \
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str w2, [x1, x3]; \
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RET;
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# endif
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# else
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# define SYSCALL_ERROR __syscall_error
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# define SYSCALL_ERROR_HANDLER \
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.Lsyscall_error: \
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b __syscall_error;
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# endif
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/* Linux takes system call args in registers:
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syscall number x8
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arg 1 x0
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arg 2 x1
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arg 3 x2
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arg 4 x3
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arg 5 x4
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arg 6 x5
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arg 7 x6
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The compiler is going to form a call by coming here, through PSEUDO, with
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arguments
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syscall number in the DO_CALL macro
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arg 1 x0
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arg 2 x1
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arg 3 x2
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arg 4 x3
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arg 5 x4
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arg 6 x5
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arg 7 x6
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*/
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# undef DO_CALL
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# define DO_CALL(syscall_name, args) \
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mov x8, SYS_ify (syscall_name); \
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svc 0
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#else /* not __ASSEMBLER__ */
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# ifdef SHARED
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# define INLINE_VSYSCALL(name, nr, args...) \
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({ \
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__label__ out; \
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__label__ iserr; \
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long sc_ret; \
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INTERNAL_SYSCALL_DECL (sc_err); \
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\
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if (__vdso_##name != NULL) \
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{ \
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sc_ret = INTERNAL_VSYSCALL_NCS (__vdso_##name, sc_err, nr, ##args); \
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if (!INTERNAL_SYSCALL_ERROR_P (sc_ret, sc_err)) \
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goto out; \
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if (INTERNAL_SYSCALL_ERRNO (sc_ret, sc_err) != ENOSYS) \
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goto iserr; \
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} \
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\
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sc_ret = INTERNAL_SYSCALL (name, sc_err, nr, ##args); \
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if (INTERNAL_SYSCALL_ERROR_P (sc_ret, sc_err)) \
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{ \
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iserr: \
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__set_errno (INTERNAL_SYSCALL_ERRNO (sc_ret, sc_err)); \
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sc_ret = -1L; \
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} \
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out: \
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sc_ret; \
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})
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# else
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# define INLINE_VSYSCALL(name, nr, args...) \
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INLINE_SYSCALL (name, nr, ##args)
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# endif
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# ifdef SHARED
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# define INTERNAL_VSYSCALL(name, err, nr, args...) \
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({ \
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__label__ out; \
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long v_ret; \
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\
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if (__vdso_##name != NULL) \
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{ \
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v_ret = INTERNAL_VSYSCALL_NCS (__vdso_##name, err, nr, ##args); \
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if (!INTERNAL_SYSCALL_ERROR_P (v_ret, err) \
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|| INTERNAL_SYSCALL_ERRNO (v_ret, err) != ENOSYS) \
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goto out; \
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} \
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v_ret = INTERNAL_SYSCALL (name, err, nr, ##args); \
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out: \
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v_ret; \
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})
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# else
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# define INTERNAL_VSYSCALL(name, err, nr, args...) \
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INTERNAL_SYSCALL (name, err, nr, ##args)
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# endif
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/* List of system calls which are supported as vsyscalls. */
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# define HAVE_CLOCK_GETRES_VSYSCALL 1
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# define HAVE_CLOCK_GETTIME_VSYSCALL 1
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# define INTERNAL_VSYSCALL_NCS(funcptr, err, nr, args...) \
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({ \
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LOAD_ARGS_##nr (args) \
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asm volatile ("blr %1" \
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: "=r" (_x0) \
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: "r" (funcptr) ASM_ARGS_##nr \
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: "x30", "memory"); \
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(long) _x0; \
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})
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/* Define a macro which expands into the inline wrapper code for a system
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call. */
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# undef INLINE_SYSCALL
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# define INLINE_SYSCALL(name, nr, args...) \
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({ unsigned long _sys_result = INTERNAL_SYSCALL (name, , nr, args); \
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if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (_sys_result, ), 0))\
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{ \
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__set_errno (INTERNAL_SYSCALL_ERRNO (_sys_result, )); \
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_sys_result = (unsigned long) -1; \
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} \
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(long) _sys_result; })
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# undef INTERNAL_SYSCALL_DECL
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# define INTERNAL_SYSCALL_DECL(err) do { } while (0)
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# undef INTERNAL_SYSCALL_RAW
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# define INTERNAL_SYSCALL_RAW(name, err, nr, args...) \
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({ long _sys_result; \
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{ \
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LOAD_ARGS_##nr (args) \
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register long _x8 asm ("x8") = (name); \
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asm volatile ("svc 0 // syscall " # name \
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: "=r" (_x0) : "r"(_x8) ASM_ARGS_##nr : "memory"); \
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_sys_result = _x0; \
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} \
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_sys_result; })
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# undef INTERNAL_SYSCALL
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# define INTERNAL_SYSCALL(name, err, nr, args...) \
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INTERNAL_SYSCALL_RAW(SYS_ify(name), err, nr, args)
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# undef INTERNAL_SYSCALL_AARCH64
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# define INTERNAL_SYSCALL_AARCH64(name, err, nr, args...) \
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INTERNAL_SYSCALL_RAW(__ARM_NR_##name, err, nr, args)
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# undef INTERNAL_SYSCALL_ERROR_P
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# define INTERNAL_SYSCALL_ERROR_P(val, err) \
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((unsigned long) (val) >= (unsigned long) -4095)
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# undef INTERNAL_SYSCALL_ERRNO
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# define INTERNAL_SYSCALL_ERRNO(val, err) (-(val))
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# define LOAD_ARGS_0() \
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register long _x0 asm ("x0");
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# define LOAD_ARGS_1(x0) \
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long _x0tmp = (long) (x0); \
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LOAD_ARGS_0 () \
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_x0 = _x0tmp;
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# define LOAD_ARGS_2(x0, x1) \
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long _x1tmp = (long) (x1); \
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LOAD_ARGS_1 (x0) \
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register long _x1 asm ("x1") = _x1tmp;
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# define LOAD_ARGS_3(x0, x1, x2) \
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long _x2tmp = (long) (x2); \
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LOAD_ARGS_2 (x0, x1) \
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register long _x2 asm ("x2") = _x2tmp;
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# define LOAD_ARGS_4(x0, x1, x2, x3) \
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long _x3tmp = (long) (x3); \
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LOAD_ARGS_3 (x0, x1, x2) \
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register long _x3 asm ("x3") = _x3tmp;
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# define LOAD_ARGS_5(x0, x1, x2, x3, x4) \
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long _x4tmp = (long) (x4); \
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LOAD_ARGS_4 (x0, x1, x2, x3) \
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register long _x4 asm ("x4") = _x4tmp;
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# define LOAD_ARGS_6(x0, x1, x2, x3, x4, x5) \
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long _x5tmp = (long) (x5); \
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LOAD_ARGS_5 (x0, x1, x2, x3, x4) \
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register long _x5 asm ("x5") = _x5tmp;
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# define LOAD_ARGS_7(x0, x1, x2, x3, x4, x5, x6)\
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long _x6tmp = (long) (x6); \
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LOAD_ARGS_6 (x0, x1, x2, x3, x4, x5) \
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register long _x6 asm ("x6") = _x6tmp;
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# define ASM_ARGS_0
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# define ASM_ARGS_1 , "r" (_x0)
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# define ASM_ARGS_2 ASM_ARGS_1, "r" (_x1)
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# define ASM_ARGS_3 ASM_ARGS_2, "r" (_x2)
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# define ASM_ARGS_4 ASM_ARGS_3, "r" (_x3)
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# define ASM_ARGS_5 ASM_ARGS_4, "r" (_x4)
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# define ASM_ARGS_6 ASM_ARGS_5, "r" (_x5)
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# define ASM_ARGS_7 ASM_ARGS_6, "r" (_x6)
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# undef INTERNAL_SYSCALL_NCS
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# define INTERNAL_SYSCALL_NCS(number, err, nr, args...) \
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INTERNAL_SYSCALL_RAW (number, err, nr, args)
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#endif /* __ASSEMBLER__ */
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/* Pointer mangling is supported for AArch64. */
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#if (defined NOT_IN_libc && defined IS_IN_rtld) || \
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(!defined SHARED && (!defined NOT_IN_libc || defined IS_IN_libpthread))
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# ifdef __ASSEMBLER__
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# define PTR_MANGLE(dst, src, guard, tmp) \
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LDST_PCREL (ldr, guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard_local)); \
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PTR_MANGLE2 (dst, src, guard)
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/* Use PTR_MANGLE2 for efficiency if guard is already loaded. */
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# define PTR_MANGLE2(dst, src, guard)\
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eor dst, src, guard
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# define PTR_DEMANGLE(dst, src, guard, tmp)\
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PTR_MANGLE (dst, src, guard, tmp)
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# define PTR_DEMANGLE2(dst, src, guard)\
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PTR_MANGLE2 (dst, src, guard)
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# else
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extern uintptr_t __pointer_chk_guard_local attribute_relro attribute_hidden;
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# define PTR_MANGLE(var) \
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(var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard_local)
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# define PTR_DEMANGLE(var) PTR_MANGLE (var)
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# endif
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#else
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# ifdef __ASSEMBLER__
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# define PTR_MANGLE(dst, src, guard, tmp) \
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LDST_GLOBAL (ldr, guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard)); \
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PTR_MANGLE2 (dst, src, guard)
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/* Use PTR_MANGLE2 for efficiency if guard is already loaded. */
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# define PTR_MANGLE2(dst, src, guard)\
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eor dst, src, guard
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# define PTR_DEMANGLE(dst, src, guard, tmp)\
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PTR_MANGLE (dst, src, guard, tmp)
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# define PTR_DEMANGLE2(dst, src, guard)\
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PTR_MANGLE2 (dst, src, guard)
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# else
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extern uintptr_t __pointer_chk_guard attribute_relro;
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# define PTR_MANGLE(var) \
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(var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard)
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# define PTR_DEMANGLE(var) PTR_MANGLE (var)
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# endif
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#endif
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#endif /* linux/aarch64/sysdep.h */
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