Messages in this thread | | | Date | Thu, 16 Feb 2012 14:06:12 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH v8 3/8] seccomp: add system call filtering using BPF |
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On 02/16/2012 01:51 PM, Will Drewry wrote: >> >> Put the bloody bit in there and let the pattern program make that decision. > > Easy enough to add a bit for the mode: 32-bit or 64-bit. It seemed > like a waste of cycles for every 32-bit program or every 64-bit > program to check to see that its calling convention hadn't changed, > but it does take away a valid decision the pattern program should be > making. > > I'll add a flag for 32bit/64bit while cleaning up seccomp_data. I > think that will properly encapsulate the is_compat_task() behavior in > a way that is stable for compat and non-compat tasks to use. If > there's a more obvious way, I'm all ears. >
is_compat_task() is not going to be the right thing for x86 going forward, as we're introducing the x32 ABI (which uses the normal x86-64 entry point, but with different eax numbers, and bit 30 set.)
The actual state is the TS_COMPAT flag in the thread_info structure, which currently matches is_compat_task(), but perhaps we should add a new helper function syscall_namespace() or something like that...
Either that or we can just use another bit in the syscall number field...
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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