On Sun, 2010-03-14 at 22:54 -0700, David Miller wrote: > From: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> > Date: Mon, 15 Mar 2010 16:18:33 +1100 > > > Or is there any good reason -not- to do that in glibc ? > > The whole point of syscall() is to handle cases where the C library > doesn't know about the system call yet. > > I think it's therefore very much "buyer beware". > > On sparc it'll never work to use the workaround you're proposing since > we pass everything in via registers. > > So arch knowledge will always need to be present in these situations. I'm not sure I follow. We also pass via register on powerpc, but the offset introduced by the sysno argument breaks register pair alignment which cannot be fixed up inside syscall(). However, if I change glibc's syscall to be something like #define syscall(sysno, args...) __syscall(0 /* dummy */, sysno, args) And make __syscall then do something like: mr r0, r4 mr r3, r5 mr r4, r6 mr r5, r7 mr r6, r8 .../... sc blr Then at least all that class of syscalls will be fixed. Of course this has to be in glibc arch code. I was merely asking if that was something our glibc folks would consider and whether somebody could think of a better solution :-) Cheers ,Ben. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
