gdb/testsuite/lib/my-syscalls.S

   1 /* This testcase is part of GDB, the GNU debugger.
   2
   3    Copyright 2020-2023 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program 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
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18
  19 /* This file implements simple Linux syscall wrappers, to be used by tests that
  20    need to know exactly where the syscall instructions are.  */
  21
  22 #include <asm/unistd.h>
  23
  24 /* The SYSCALL macro below current supports calling syscalls with up
  25    to 3 arguments, and, assumes the syscall never returns, like exec
  26    and exit.  If you need to call syscalls with more arguments or you
  27    need to call syscalls that actually return, you'll need to update
  28    the macros.  We don't bother with optimizing setting up fewer
  29    arguments for syscalls that take fewer arguments, as we're not
  30    optimizating for speed or space, but for maintainability.  */
  31
  32 #if defined(__x86_64__)
  33
  34 #define SYSCALL(NAME, NR)       \
  35 .global NAME                    ;\
  36 NAME:                           ;\
  37         mov $NR, %rax           ;\
  38         /* rdi, rsi and rdx already contain the right arguments.  */ \
  39 NAME ## _syscall:               ;\
  40         syscall                 ;\
  41         ret                     ;
  42
  43 #elif defined(__i386__)
  44
  45 #define SYSCALL(NAME, NR)       \
  46 .global NAME                    ;\
  47 NAME:                           ;\
  48         mov $NR, %eax           ;\
  49         mov 4(%esp), %ebx       ;\
  50         mov 8(%esp), %ecx       ;\
  51         mov 12(%esp), %edx      ;\
  52 NAME ## _syscall:               ;\
  53         int $0x80               ;\
  54         ret
  55
  56 #elif defined(__aarch64__)
  57
  58 #define SYSCALL(NAME, NR)       \
  59 .global NAME                    ;\
  60 NAME:                           ;\
  61         mov x8, NR              ;\
  62         /* x0, x1 and x2 already contain the right arguments.  */ \
  63 NAME ## _syscall:               ;\
  64         svc #0
  65
  66 #else
  67 # error "Unsupported architecture"
  68 #endif
  69
  70 SYSCALL (my_execve, __NR_execve)
  71
  72 /* void my_exit (int code);  */
  73
  74 SYSCALL (my_exit, __NR_exit)
  75
  76         .section        .note.GNU-stack,"",@progbits