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>>>>> On Fri, 31 Oct 2003 15:47:24 +0100, Jakub Jelinek <jakub@redhat.com> said: Jakub> On Fri, Oct 31, 2003 at 08:45:22AM -0800, David Mosberger wrote: >> >>>>> On Fri, 31 Oct 2003 08:01:14 +0100, Jakub Jelinek <jakub@redhat.com> said: Jakub> Cannot tcbhead_t's private field be reused for the sysinfo pointer Jakub> actually on IA-64? >> As long as we can make it appear at offsets -8, that would be OK. Jakub> It would be offset 8, not -8 actually. Ah, you mean _that_ one. It's defined by the psABI and since the new syscall stub was defined much later, I considered it off limits. I'd hate to change the offset now, many months after an open discussion on this topic. On the other hand, if we do want to change it, now is probably the last chance. Jakub> That way 32 bytes wouldn't have to be wasted at end of struct Jakub> pthread, it would be at the same location in linuxthreads as Jakub> well as NPTL build I don't think you have to waste 32 bytes. You could do something like: struct pthread { : long reserved; }; and then access sys_info via ((long *) tcb_pointer)[-1]. That way, no matter what the alignment, you'll always access the right word and will only use up an extra 8 bytes. >> That's not sufficient. The offset must be the same across _all_ libcs, >> so that non-libc code can use the new syscall stubs as well. Jakub> I don't think it is a good idea to give access to glibc Jakub> internals (which these are) to outside code. There is Jakub> syscall(3) function for a reason. It's not glibc internals, it's ia64 linux abi. I certainly do not encourage the use of handcrafted syscall stubs, but sometimes, they're needed. Jakub> Also, derefencing r13[-8] (or r13[8]) in various syscall stub Jakub> macros is not going to work if you run the program then Jakub> against older glibc and there won't be any symbol versioning Jakub> which would catch it up. If someone chooses to use the new syscall stubs, they'll have to live with that. --david
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