From: Pedro Alves <pedro@palves.net>
To: gdb-patches@sourceware.org
Cc: Andrew Burgess <aburgess@redhat.com>
Subject: [FYI/pushed v4 22/25] gdb/testsuite/lib/my-syscalls.S: Refactor new SYSCALL macro
Date: Mon, 13 Nov 2023 15:04:24 +0000 [thread overview]
Message-ID: <20231113150427.477431-23-pedro@palves.net> (raw)
In-Reply-To: <20231113150427.477431-1-pedro@palves.net>
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
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
---
gdb/testsuite/lib/my-syscalls.S | 50 +++++++++++++++++++++------------
1 file changed, 32 insertions(+), 18 deletions(-)
diff --git a/gdb/testsuite/lib/my-syscalls.S b/gdb/testsuite/lib/my-syscalls.S
index c0dbd0dffea..38299e45284 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
--
2.34.1
next prev parent reply other threads:[~2023-11-13 15:06 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-13 15:04 [FYI/pushed v4 00/25] Step over thread clone and thread exit Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 01/25] Add "maint info linux-lwps" command Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 02/25] gdb/linux: Delete all other LWPs immediately on ptrace exec event Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 03/25] Step over clone syscall w/ breakpoint, TARGET_WAITKIND_THREAD_CLONED Pedro Alves
2023-11-14 12:55 ` Guinevere Larsen
2023-11-14 13:26 ` Pedro Alves
2023-11-14 16:29 ` Guinevere Larsen
2023-11-14 16:44 ` Luis Machado
2023-11-14 13:28 ` Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 04/25] Support clone events in the remote protocol Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 05/25] Avoid duplicate QThreadEvents packets Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 06/25] Thread options & clone events (core + remote) Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 07/25] Thread options & clone events (native Linux) Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 08/25] Thread options & clone events (Linux GDBserver) Pedro Alves
2024-02-06 11:04 ` Luis Machado
2024-02-06 14:57 ` Tom Tromey
2024-02-06 15:12 ` Luis Machado
2024-02-07 8:59 ` Luis Machado
2024-02-07 15:43 ` Tom Tromey
2024-02-07 17:10 ` Simon Marchi
2024-02-07 18:05 ` Luis Machado
2024-02-07 18:18 ` Tom Tromey
2024-02-07 18:56 ` Pedro Alves
2024-02-07 20:11 ` Pedro Alves
2024-02-08 8:57 ` Luis Machado
2024-02-08 10:53 ` Pedro Alves
2024-02-08 11:47 ` Luis Machado
2024-02-08 14:58 ` Tom Tromey
2024-02-07 18:06 ` Tom Tromey
2023-11-13 15:04 ` [FYI/pushed v4 09/25] gdbserver: Hide and don't detach pending clone children Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 10/25] Remove gdb/19675 kfails (displaced stepping + clone) Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 11/25] all-stop/synchronous RSP support thread-exit events Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 12/25] gdbserver/linux-low.cc: Ignore event_ptid if TARGET_WAITKIND_IGNORE Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 13/25] Move deleting thread on TARGET_WAITKIND_THREAD_EXITED to core Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 14/25] Introduce GDB_THREAD_OPTION_EXIT thread option, fix step-over-thread-exit Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 15/25] Implement GDB_THREAD_OPTION_EXIT support for Linux GDBserver Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 16/25] Implement GDB_THREAD_OPTION_EXIT support for native Linux Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 17/25] gdb: clear step over information on thread exit (PR gdb/27338) Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 18/25] stop_all_threads: (re-)enable async before waiting for stops Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 19/25] gdbserver: Queue no-resumed event after thread exit Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 20/25] Don't resume new threads if scheduler-locking is in effect Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 21/25] Report thread exit event for leader if reporting thread exit events Pedro Alves
2023-11-13 15:04 ` Pedro Alves [this message]
2023-11-13 15:04 ` [FYI/pushed v4 23/25] Testcases for stepping over thread exit syscall (PR gdb/27338) Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 24/25] Document remote clone events, and QThreadOptions packet Pedro Alves
2023-11-13 15:04 ` [FYI/pushed v4 25/25] Cancel execution command on thread exit, when stepping, nexting, etc Pedro Alves
2023-11-13 19:28 ` [FYI/pushed v4 00/25] Step over thread clone and thread exit Tom de Vries
2023-11-14 10:51 ` Pedro Alves
2023-11-14 13:39 ` Tom de Vries
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