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| author | Pedro Alves <pedro@palves.net> | 2021-07-02 11:46:40 +0100 |
|---|---|---|
| committer | Pedro Alves <pedro@palves.net> | 2022-12-12 20:01:20 +0000 |
| commit | cd204162fae435ff950ef300d14f1e0cb084f9fd (patch) | |
| tree | 24055fe0c795da8bc4c196a9b08896d6aa2fafc8 | |
| parent | 9d40da2ccb5a79e7b7b484b1a8508bdef9b42d43 (diff) | |
| download | gdb-cd204162fae435ff950ef300d14f1e0cb084f9fd.zip gdb-cd204162fae435ff950ef300d14f1e0cb084f9fd.tar.gz gdb-cd204162fae435ff950ef300d14f1e0cb084f9fd.tar.bz2 | |
gdb/testsuite/lib/my-syscalls.S: Refactor new SYSCALL macro
Refactor the syscall assembly code in gdb/testsuite/lib/my-syscalls.S
behind a SYSCALL macro so that it's easy to add new syscalls without
duplicating code.
Note that the way the macro is implemented, it only works correctly
for syscalls with up to 3 arguments, and, if the syscall doesn't
return (the macro doesn't bother to save/restore callee-saved
registers).
The following patch will want to use the macro to define a wrapper for
the "exit" syscall, so the limitations continue to be sufficient.
Change-Id: I8acf1463b11a084d6b4579aaffb49b5d0dea3bba
| -rw-r--r-- | gdb/testsuite/lib/my-syscalls.S | 50 |
1 files changed, 32 insertions, 18 deletions
diff --git a/gdb/testsuite/lib/my-syscalls.S b/gdb/testsuite/lib/my-syscalls.S index 7f06f9c..6fb5362 100644 --- a/gdb/testsuite/lib/my-syscalls.S +++ b/gdb/testsuite/lib/my-syscalls.S @@ -21,38 +21,52 @@ #include <asm/unistd.h> -/* int my_execve (const char *file, char *argv[], char *envp[]); */ - -.global my_execve -my_execve: +/* The SYSCALL macro below current supports calling syscalls with up + to 3 arguments, and, assumes the syscall never returns, like exec + and exit. If you need to call syscalls with more arguments or you + need to call syscalls that actually return, you'll need to update + the macros. We don't bother with optimizing setting up fewer + arguments for syscalls that take fewer arguments, as we're not + optimizating for speed or space, but for maintainability. */ #if defined(__x86_64__) - mov $__NR_execve, %rax - /* rdi, rsi and rdx already contain the right arguments. */ -my_execve_syscall: - syscall - ret +#define SYSCALL(NAME, NR) \ +.global NAME ;\ +NAME: ;\ + mov $NR, %rax ;\ + /* rdi, rsi and rdx already contain the right arguments. */ \ +NAME ## _syscall: ;\ + syscall ;\ + ret ; #elif defined(__i386__) - mov $__NR_execve, %eax - mov 4(%esp), %ebx - mov 8(%esp), %ecx - mov 12(%esp), %edx -my_execve_syscall: - int $0x80 +#define SYSCALL(NAME, NR) \ +.global NAME ;\ +NAME: ;\ + mov $NR, %eax ;\ + mov 4(%esp), %ebx ;\ + mov 8(%esp), %ecx ;\ + mov 12(%esp), %edx ;\ +NAME ## _syscall: ;\ + int $0x80 ;\ ret #elif defined(__aarch64__) - mov x8, #__NR_execve - /* x0, x1 and x2 already contain the right arguments. */ -my_execve_syscall: +#define SYSCALL(NAME, NR) \ +.global NAME ;\ +NAME: ;\ + mov x8, NR ;\ + /* x0, x1 and x2 already contain the right arguments. */ \ +NAME ## _syscall: ;\ svc #0 #else # error "Unsupported architecture" #endif +SYSCALL (my_execve, __NR_execve) + .section .note.GNU-stack,"",@progbits |