On Fri, Apr 11, 2014 at 01:45:02PM +0100, Russell King - ARM Linux wrote: > On Fri, Apr 11, 2014 at 02:02:32PM +0200, Miklos Szeredi wrote: > > On Fri, Apr 11, 2014 at 1:54 PM, Russell King - ARM Linux > > <linux@xxxxxxxxxxxxxxxx> wrote: > > > On Fri, Apr 11, 2014 at 01:50:50PM +0200, Miklos Szeredi wrote: > > >> Yes, and the padding will be of wrong length if NR_syscalls is > > >> incorrect (which may be Oopsable?). At least that is my impression > > >> from a casual glance. > > > > > > Please explain. > > > > Look at ending lines of arch/arm/kernel/calls.S: if NR_syscalls is a > > multiple of 4, then syscalls_padding will be zero. I.e. no padding > > despite the fact that there is in fact only 382 system calls in table > > and there should be 2 sys_ni_syscall pads. > > Hmm, it looks like you're right... this used to work fine until... > > commit 1f66e06fb6414732bef7bf4a071ef76a837badec > Author: Wade Farnsworth <wade_farnsworth@xxxxxxxxxx> > Date: Fri Sep 7 18:18:25 2012 +0100 > > ARM: 7524/1: support syscall tracing > > because the tracing code wanted to know the number of syscalls. I don't > know what the answer is here, because the current solution is IMHO far > to fragile. Actually, no, you're wrong. Look closely at the definitions. __NR_syscalls is not the same as NR_syscalls. __NR_syscalls is the statically defined size of the syscall table for *probes purposes. NR_syscalls is the assembly-counted number of CALL() macros in arch/arm/kernel/calls.S. So, patch 2 isn't required, and patch 3 needs to be fixed up to take this into account... -- FTTC broadband for 0.8mile line: now at 9.7Mbps down 460kbps up... slowly improving, and getting towards what was expected from it. -- 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
