On 03/02, John Reiser wrote: > > Oleg Nesterov wrote: > > > Still, I don't understand why we don't pass NEW_AUX_ENT(AT_SYSINFO) when > > vdso_enabled == 0. We don't need linux-gate.so to use __kernel_vsyscall, > > we have FIX_VDSO. In that case we should s/PAGE_KERNEL_RO/PAGE_READONLY/ > > of course. I guess the reason is some magic in glibc. > > In the past there were problems where user code could not single-step > (or even read the code of) such system calls. Can these two operations > be performed today with what you propose, particularly if FIX_VDSO is > near 0xfffff000 ?
No, we can't COW the gate page, it lives in swapper_pg_dir. I am not sure why we could not read it, we have gate_vma for that. So, the reason is debugger. Thanks. Oleg. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
