On Mon, 2010-03-15 at 14:44 +0100, Ralf Baechle wrote: > Syscall is most often used for new syscalls that have no syscall stub in > glibc yet, so the user of syscall() encodes this ABI knowledge. If at a > later stage syscall() is changed to have this sort of knowledge we break > the API. This is something only the kernel can get right. Well, no. The change I propose would not break the ABI on powerpc and would auto-magically fix thoses cases :-) But again, you don't have to do the same thing on MIPS or sparc, it's definitely arch specific. IE. What you are saying is that a syscall defined in the kernel as: sys_foo(u64 arg); To be called from userspace would require something like: u64 arg = 0x123456789abcdef01; #if defined(__powerpc__) && WORDSIZE == 32 syscall(SYS_foo, (u32)(arg >> 32), (u32)arg); #ese syscall(SYS_foo, arg); While with the trick of making syscall a macro wrapping an underlying __syscall that has an added dummy argument, the register alignment is "corrected" and thus -both- forms above suddenly work for me. That might actually work for you too. 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
