[v3,3/5] gdbstub: Add syscall entry/return hooks

Commit Message

Ilya Leoshkevich Feb. 2, 2024, 3:23 p.m. UTC

The upcoming syscall catchpoint support needs to get control on syscall
entry and return. Provide the necessary hooks for that, which are
no-ops for now.

Signed-off-by: Ilya Leoshkevich <[e-mail]>
---
 gdbstub/user.c               |  8 ++++++++
 include/gdbstub/user.h       | 13 +++++++++++++
 include/user/syscall-trace.h |  7 +++++--
 3 files changed, 26 insertions(+), 2 deletions(-)

Patch

diff --git a/gdbstub/user.c b/gdbstub/user.c
index 63edca131ab..2ba01c17faf 100644
--- a/gdbstub/user.c
+++ b/gdbstub/user.c
@@ -502,3 +502,11 @@  void gdb_syscall_handling(const char *syscall_packet)
     gdb_put_packet(syscall_packet);
     gdb_handlesig(gdbserver_state.c_cpu, 0);
 }
+
+void gdb_syscall_entry(CPUState *cs, int num)
+{
+}
+
+void gdb_syscall_return(CPUState *cs, int num)
+{
+}
diff --git a/include/gdbstub/user.h b/include/gdbstub/user.h
index 1fc43e04af5..68b6534130c 100644
--- a/include/gdbstub/user.h
+++ b/include/gdbstub/user.h
@@ -51,5 +51,18 @@  void gdb_signalled(CPUArchState *as, int sig);
  */
 void gdbserver_fork(CPUState *cs);
 
+/**
+ * gdb_syscall_entry() - inform gdb of syscall entry and yield control to it
+ * @cs: CPU
+ * @num: syscall number
+ */
+void gdb_syscall_entry(CPUState *cs, int num);
+
+/**
+ * gdb_syscall_entry() - inform gdb of syscall return and yield control to it
+ * @cs: CPU
+ * @num: syscall number
+ */
+void gdb_syscall_return(CPUState *cs, int num);
 
 #endif /* GDBSTUB_USER_H */
diff --git a/include/user/syscall-trace.h b/include/user/syscall-trace.h
index 557f881a79b..b48b2b2d0ae 100644
--- a/include/user/syscall-trace.h
+++ b/include/user/syscall-trace.h
@@ -11,6 +11,7 @@ 
 #define SYSCALL_TRACE_H
 
 #include "exec/user/abitypes.h"
+#include "gdbstub/user.h"
 #include "qemu/plugin.h"
 #include "trace/trace-root.h"
 
@@ -20,7 +21,7 @@ 
  * could potentially unify the -strace code here as well.
  */
 
-static inline void record_syscall_start(void *cpu, int num,
+static inline void record_syscall_start(CPUState *cpu, int num,
                                         abi_long arg1, abi_long arg2,
                                         abi_long arg3, abi_long arg4,
                                         abi_long arg5, abi_long arg6,
@@ -29,11 +30,13 @@  static inline void record_syscall_start(void *cpu, int num,
     qemu_plugin_vcpu_syscall(cpu, num,
                              arg1, arg2, arg3, arg4,
                              arg5, arg6, arg7, arg8);
+    gdb_syscall_entry(cpu, num);
 }
 
-static inline void record_syscall_return(void *cpu, int num, abi_long ret)
+static inline void record_syscall_return(CPUState *cpu, int num, abi_long ret)
 {
     qemu_plugin_vcpu_syscall_ret(cpu, num, ret);
+    gdb_syscall_return(cpu, num);
 }