Messages in this thread | | | Date | Sun, 13 Feb 2011 13:16:57 -0800 | From | "H. Peter Anvin" <> | Subject | Re: X32 psABI status |
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On 02/13/2011 01:10 PM, H.J. Lu wrote: >>> >>> 1. Kernel interface with syscall is close to be finalized. >>
I don't think calling it "finalized" is accurate... it is more accurately described as "prototyped".
>> Really? I haven't seen this being posted for review yet ;-) >> >> The basic concept looks entirely reasonable to me, but I'm >> curious what drove the decision to start out with the x86_64 >> system calls instead of the generic ones. >> >> Since tile was merged, we now have support for compat syscalls >> in the generic syscall ABI. I would have assumed that it >> was possible to just use those if you decide to do a new >> ABI in the first place. >> >> The other option that would have appeared natural to me is >> to just use the existing 32 bit compat ABI with the few >> necessary changes done based on the personality.
The actual idea is to use the i386 compat ABI for memory layout, but with a 64-bit register convention. That means that system calls that don't make references to memory structures can simply use the 64-bit system calls, otherwise we're planning to reuse the i386 compat system calls, but invoke them via the syscall instruction (which requires a new system call table) and to pass 64-bit arguments in single registers.
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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