Re: [qemu-s390x] [Qemu-devel] [PULL v3 47/55] linux headers: update against Linux 5.2-rc1

[Laurent Vivier]

On 23/05/2019 13:56, Cornelia Huck wrote:
> On Wed, 22 May 2019 15:22:23 +0200
> Aleksandar Markovic <address@hidden> wrote:
> 
>> The alternative way of invoking via IPCV6 (else part of “ifdef
>> __NR_MSGSND”) should work for MIPS in the present stage of headers and
>> kernel.
> 
> I tried to do that so that we have at least a workaround for now; but
> this fails building on my x86 laptop (the safe_syscall6 for ipc
> complains about missing __NR_ipc). Maybe I'm holding it wrong (should
> that be conditional on the host?), but I think that really needs to be
> done by the mips maintainers...
> 

Perhaps a simple workaround could be:

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index e311fcda0517..5b431736032c 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -761,14 +761,8 @@ safe_syscall2(int, nanosleep, const struct timespec *, req,
 safe_syscall4(int, clock_nanosleep, const clockid_t, clock, int, flags,
               const struct timespec *, req, struct timespec *, rem)
 #endif
-#ifdef __NR_msgsnd
-safe_syscall4(int, msgsnd, int, msgid, const void *, msgp, size_t, sz,
-              int, flags)
-safe_syscall5(int, msgrcv, int, msgid, void *, msgp, size_t, sz,
-              long, msgtype, int, flags)
-safe_syscall4(int, semtimedop, int, semid, struct sembuf *, tsops,
-              unsigned, nsops, const struct timespec *, timeout)
-#else
+
+#ifdef __NR_ipc
 /* This host kernel architecture uses a single ipc syscall; fake up
  * wrappers for the sub-operations to hide this implementation detail.
  * Annoyingly we can't include linux/ipc.h to get the constant definitions
@@ -783,14 +777,30 @@ safe_syscall4(int, semtimedop, int, semid, struct sembuf 
*, tsops,
 
 safe_syscall6(int, ipc, int, call, long, first, long, second, long, third,
               void *, ptr, long, fifth)
+#endif
+
+#ifdef __NR_msgsnd
+safe_syscall4(int, msgsnd, int, msgid, const void *, msgp, size_t, sz,
+              int, flags)
+#else
 static int safe_msgsnd(int msgid, const void *msgp, size_t sz, int flags)
 {
     return safe_ipc(Q_IPCCALL(0, Q_MSGSND), msgid, sz, flags, (void *)msgp, 0);
 }
+#endif
+#ifdef __NR_msgrcv
+safe_syscall5(int, msgrcv, int, msgid, void *, msgp, size_t, sz,
+              long, msgtype, int, flags)
+#else
 static int safe_msgrcv(int msgid, void *msgp, size_t sz, long type, int flags)
 {
     return safe_ipc(Q_IPCCALL(1, Q_MSGRCV), msgid, sz, flags, msgp, type);
 }
+#endif
+#ifdef __NR_semtimedop
+safe_syscall4(int, semtimedop, int, semid, struct sembuf *, tsops,
+              unsigned, nsops, const struct timespec *, timeout)
+#else
 static int safe_semtimedop(int semid, struct sembuf *tsops, unsigned nsops,
                            const struct timespec *timeout)
 {