diff mbox series

[v2,052/108] linux-user: Unwrap TARGET_NR_syscall early

Message ID 20180610030220.3777-53-richard.henderson@linaro.org
State New
Headers show
Series linux-user: Split do_syscall | expand

Commit Message

Richard Henderson June 10, 2018, 3:01 a.m. UTC 
Unwrapping early produces a much nicer log output.
Disallow recursive syscall, as per ARM and MIPS.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

---
 linux-user/syscall.c | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

-- 
2.17.1
diff mbox series

Patch

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 4f6c01092b..87374014b1 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -10230,11 +10230,6 @@  static abi_long do_syscall1(void *cpu_env, unsigned num, abi_long arg1,
     switch(num) {
     case TARGET_NR_vhangup:
         return get_errno(vhangup());
-#ifdef TARGET_NR_syscall
-    case TARGET_NR_syscall:
-        return do_syscall(cpu_env, arg1 & 0xffff, arg2, arg3, arg4, arg5,
-                          arg6, arg7, arg8, 0);
-#endif
     case TARGET_NR_wait4:
         {
             int status;
@@ -13171,6 +13166,32 @@  abi_long do_syscall(void *cpu_env, unsigned num, abi_long arg1,
         }
     }
 #endif
+#ifdef TARGET_NR_syscall
+    /* For the benefit of strace, unwrap NR_syscall now.  */
+    if (num == TARGET_NR_syscall) {
+        num = arg1 & 0xffff;
+        if (num == TARGET_NR_syscall) {
+            /* Do not allow recursion.  */
+            ret = -TARGET_ENOSYS;
+            trace_guest_user_syscall(cpu, num, arg1, arg2, arg3, arg4,
+                                     arg5, arg6, arg7, arg8);
+            if (unlikely(do_strace)) {
+                print_syscall(num, arg1, arg2, arg3, arg4, arg5, arg6);
+                print_syscall_ret(num, ret);
+            }
+            trace_guest_user_syscall_ret(cpu, num, ret);
+            return ret;
+        }
+        arg1 = arg2;
+        arg2 = arg3;
+        arg3 = arg4;
+        arg4 = arg5;
+        arg5 = arg6;
+        arg6 = arg7;
+        arg7 = arg8;
+        arg8 = 0;
+    }
+#endif
 
     trace_guest_user_syscall(cpu, num, arg1, arg2, arg3, arg4,
                              arg5, arg6, arg7, arg8);