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      1 /* Copyright (C) 2005-2025 Free Software Foundation, Inc.
      2 
      3    This file is part of the GNU C Library.
      4 
      5    The GNU C Library is free software; you can redistribute it and/or
      6    modify it under the terms of the GNU Lesser General Public License as
      7    published by the Free Software Foundation; either version 2.1 of the
      8    License, or (at your option) any later version.
      9 
     10    The GNU C Library is distributed in the hope that it will be useful,
     11    but WITHOUT ANY WARRANTY; without even the implied warranty of
     12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     13    Lesser General Public License for more details.
     14 
     15    You should have received a copy of the GNU Lesser General Public
     16    License along with the GNU C Library; if not, see
     17    <https://www.gnu.org/licenses/>.  */
     18 
     19 #ifndef _LINUX_AARCH64_SYSDEP_H
     20 #define _LINUX_AARCH64_SYSDEP_H 1
     21 
     22 #include <sysdeps/unix/sysdep.h>
     23 #include <sysdeps/aarch64/sysdep.h>
     24 #include <sysdeps/unix/sysdep.h>
     25 #include <sysdeps/unix/sysv/linux/sysdep.h>
     26 
     27 /* Defines RTLD_PRIVATE_ERRNO and USE_DL_SYSINFO.  */
     28 #include <dl-sysdep.h>
     29 
     30 #include <tls.h>
     31 
     32 /* In order to get __set_errno() definition in INLINE_SYSCALL.  */
     33 #ifndef __ASSEMBLER__
     34 #include <errno.h>
     35 #endif
     36 
     37 /* For Linux we can use the system call table in the header file
     38 	/usr/include/asm/unistd.h
     39    of the kernel.  But these symbols do not follow the SYS_* syntax
     40    so we have to redefine the `SYS_ify' macro here.  */
     41 #undef SYS_ify
     42 #define SYS_ify(syscall_name)	(__NR_##syscall_name)
     43 
     44 #ifdef __ASSEMBLER__
     45 
     46 /* Linux uses a negative return value to indicate syscall errors,
     47    unlike most Unices, which use the condition codes' carry flag.
     48 
     49    Since version 2.1 the return value of a system call might be
     50    negative even if the call succeeded.  E.g., the `lseek' system call
     51    might return a large offset.  Therefore we must not anymore test
     52    for < 0, but test for a real error by making sure the value in R0
     53    is a real error number.  Linus said he will make sure the no syscall
     54    returns a value in -1 .. -4095 as a valid result so we can safely
     55    test with -4095.  */
     56 
     57 # undef	PSEUDO
     58 # define PSEUDO(name, syscall_name, args)				      \
     59   .text;								      \
     60   ENTRY (name);								      \
     61     DO_CALL (syscall_name, args);					      \
     62     cmn x0, #4095;							      \
     63     b.cs .Lsyscall_error;
     64 
     65 # undef	PSEUDO_END
     66 # define PSEUDO_END(name)						      \
     67   SYSCALL_ERROR_HANDLER							      \
     68   END (name)
     69 
     70 # undef	PSEUDO_NOERRNO
     71 # define PSEUDO_NOERRNO(name, syscall_name, args)			      \
     72   .text;								      \
     73   ENTRY (name);								      \
     74     DO_CALL (syscall_name, args);
     75 
     76 # undef	PSEUDO_END_NOERRNO
     77 # define PSEUDO_END_NOERRNO(name)					      \
     78   END (name)
     79 
     80 # define ret_NOERRNO ret
     81 
     82 /* The function has to return the error code.  */
     83 # undef	PSEUDO_ERRVAL
     84 # define PSEUDO_ERRVAL(name, syscall_name, args) \
     85   .text;								      \
     86   ENTRY (name)								      \
     87     DO_CALL (syscall_name, args);					      \
     88     neg x0, x0
     89 
     90 # undef	PSEUDO_END_ERRVAL
     91 # define PSEUDO_END_ERRVAL(name) \
     92   END (name)
     93 
     94 # define ret_ERRVAL ret
     95 
     96 # if !IS_IN (libc)
     97 #  define SYSCALL_ERROR  .Lsyscall_error
     98 #  if RTLD_PRIVATE_ERRNO
     99 #   define SYSCALL_ERROR_HANDLER				\
    100 .Lsyscall_error:						\
    101 	adrp	x1, C_SYMBOL_NAME(rtld_errno);			\
    102 	neg     w0, w0;						\
    103 	str     w0, [x1, :lo12:C_SYMBOL_NAME(rtld_errno)];	\
    104 	mov	x0, -1;						\
    105 	RET;
    106 #  else
    107 
    108 #   define SYSCALL_ERROR_HANDLER				\
    109 .Lsyscall_error:						\
    110 	adrp	x1, :gottprel:errno;				\
    111 	neg	w2, w0;						\
    112 	ldr	PTR_REG(1), [x1, :gottprel_lo12:errno];		\
    113 	mrs	x3, tpidr_el0;					\
    114 	mov	x0, -1;						\
    115 	str	w2, [x1, x3];					\
    116 	RET;
    117 #  endif
    118 # else
    119 #  define SYSCALL_ERROR __syscall_error
    120 #  define SYSCALL_ERROR_HANDLER                                 \
    121 .Lsyscall_error:                                                \
    122 	b	__syscall_error;
    123 # endif
    124 
    125 /* Linux takes system call args in registers:
    126 	syscall number	x8
    127 	arg 1		x0
    128 	arg 2		x1
    129 	arg 3		x2
    130 	arg 4		x3
    131 	arg 5		x4
    132 	arg 6		x5
    133 	arg 7		x6
    134 
    135    The compiler is going to form a call by coming here, through PSEUDO, with
    136    arguments
    137 	syscall number	in the DO_CALL macro
    138 	arg 1		x0
    139 	arg 2		x1
    140 	arg 3		x2
    141 	arg 4		x3
    142 	arg 5		x4
    143 	arg 6		x5
    144 	arg 7		x6
    145 
    146 */
    147 
    148 # undef	DO_CALL
    149 # define DO_CALL(syscall_name, args)		\
    150     mov x8, SYS_ify (syscall_name);		\
    151     svc 0
    152 
    153 #else /* not __ASSEMBLER__ */
    154 
    155 # define VDSO_NAME  "LINUX_2.6.39"
    156 # define VDSO_HASH  123718537
    157 
    158 /* List of system calls which are supported as vsyscalls.  */
    159 # define HAVE_CLOCK_GETRES64_VSYSCALL	"__kernel_clock_getres"
    160 # define HAVE_CLOCK_GETTIME64_VSYSCALL	"__kernel_clock_gettime"
    161 # define HAVE_GETTIMEOFDAY_VSYSCALL	"__kernel_gettimeofday"
    162 # define HAVE_GETRANDOM_VSYSCALL        "__kernel_getrandom"
    163 
    164 # define HAVE_CLONE3_WRAPPER		1
    165 
    166 # undef INTERNAL_SYSCALL_RAW
    167 # define INTERNAL_SYSCALL_RAW(name, nr, args...)		\
    168   ({ long _sys_result;						\
    169      {								\
    170        LOAD_ARGS_##nr (args)					\
    171        register long _x8 asm ("x8") = (name);			\
    172        asm volatile ("svc	0	// syscall " # name     \
    173 		     : "=r" (_x0) : "r"(_x8) ASM_ARGS_##nr : "memory");	\
    174        _sys_result = _x0;					\
    175      }								\
    176      _sys_result; })
    177 
    178 # undef INTERNAL_SYSCALL
    179 # define INTERNAL_SYSCALL(name, nr, args...)			\
    180 	INTERNAL_SYSCALL_RAW(SYS_ify(name), nr, args)
    181 
    182 # undef INTERNAL_SYSCALL_AARCH64
    183 # define INTERNAL_SYSCALL_AARCH64(name, nr, args...)		\
    184 	INTERNAL_SYSCALL_RAW(__ARM_NR_##name, nr, args)
    185 
    186 # define LOAD_ARGS_0()				\
    187   register long _x0 asm ("x0");
    188 # define LOAD_ARGS_1(x0)			\
    189   long _x0tmp = (long) (x0);			\
    190   LOAD_ARGS_0 ()				\
    191   _x0 = _x0tmp;
    192 # define LOAD_ARGS_2(x0, x1)			\
    193   long _x1tmp = (long) (x1);			\
    194   LOAD_ARGS_1 (x0)				\
    195   register long _x1 asm ("x1") = _x1tmp;
    196 # define LOAD_ARGS_3(x0, x1, x2)		\
    197   long _x2tmp = (long) (x2);			\
    198   LOAD_ARGS_2 (x0, x1)				\
    199   register long _x2 asm ("x2") = _x2tmp;
    200 # define LOAD_ARGS_4(x0, x1, x2, x3)		\
    201   long _x3tmp = (long) (x3);			\
    202   LOAD_ARGS_3 (x0, x1, x2)			\
    203   register long _x3 asm ("x3") = _x3tmp;
    204 # define LOAD_ARGS_5(x0, x1, x2, x3, x4)	\
    205   long _x4tmp = (long) (x4);			\
    206   LOAD_ARGS_4 (x0, x1, x2, x3)			\
    207   register long _x4 asm ("x4") = _x4tmp;
    208 # define LOAD_ARGS_6(x0, x1, x2, x3, x4, x5)	\
    209   long _x5tmp = (long) (x5);			\
    210   LOAD_ARGS_5 (x0, x1, x2, x3, x4)		\
    211   register long _x5 asm ("x5") = _x5tmp;
    212 # define LOAD_ARGS_7(x0, x1, x2, x3, x4, x5, x6)\
    213   long _x6tmp = (long) (x6);			\
    214   LOAD_ARGS_6 (x0, x1, x2, x3, x4, x5)		\
    215   register long _x6 asm ("x6") = _x6tmp;
    216 
    217 # define ASM_ARGS_0
    218 # define ASM_ARGS_1	, "r" (_x0)
    219 # define ASM_ARGS_2	ASM_ARGS_1, "r" (_x1)
    220 # define ASM_ARGS_3	ASM_ARGS_2, "r" (_x2)
    221 # define ASM_ARGS_4	ASM_ARGS_3, "r" (_x3)
    222 # define ASM_ARGS_5	ASM_ARGS_4, "r" (_x4)
    223 # define ASM_ARGS_6	ASM_ARGS_5, "r" (_x5)
    224 # define ASM_ARGS_7	ASM_ARGS_6, "r" (_x6)
    225 
    226 # undef INTERNAL_SYSCALL_NCS
    227 # define INTERNAL_SYSCALL_NCS(number, nr, args...)	\
    228 	INTERNAL_SYSCALL_RAW (number, nr, args)
    229 
    230 #undef HAVE_INTERNAL_BRK_ADDR_SYMBOL
    231 #define HAVE_INTERNAL_BRK_ADDR_SYMBOL 1
    232 
    233 #endif	/* __ASSEMBLER__ */
    234 
    235 #endif /* linux/aarch64/sysdep.h */