Messages in this thread | | | Subject | Re: [PATCH] linux-2.5.43_vsyscall_A0 | From | Andreas Jaeger <> | Date | Sun, 20 Oct 2002 15:19:32 +0200 |
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Andi Kleen <ak@muc.de> writes:
> [full quote for context] > > On Sat, Oct 19, 2002 at 06:49:59AM +0200, Jeff Dike wrote: >> ak@muc.de said: >> > Guess you'll have some problems then with UML on x86-64, which always >> > uses vgettimeofday. But it's only used for gettimeofday() currently, >> > perhaps it's not that bad when the UML child runs with the host's >> > time. >> >> It's not horrible, but it's still broken. There are people who depend >> on UML being able to keep its own time separately from the host. >> >> > I guess it would be possible to add some support for UML to map own >> > code over the vsyscall reserved locations. UML would need to use the >> > syscalls then. But it'll be likely ugly. >> >> Yeah, it would be. >> >> My preferred solution would be for libc to ask the kernel where the vsyscall >> area is. That's reasonably clean and virtualizable. Andrea doesn't like it >> because it adds a few instructions to the vsyscall address calculation. > > I would have no problems with adding that to the x86-64 kernel. It could > be passed in by the ELF environment vector and added to the ABI. > Overhead should be negligible, it just needs a single table lookup. > Andreas, what do you think ?
Create a new AT_ constant, and pass it via the auxiliary vector and we can use it in glibc.
Andreas -- Andreas Jaeger SuSE Labs aj@suse.de private aj@arthur.inka.de http://www.suse.de/~aj - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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