On Sat, May 21, 2011 at 1:01 PM, Anvin, H Peter <h.peter.an...@intel.com> wrote: > I'll look at it but possibly not until the weekend.
I checked it into hjl/x32/syscall branch at http://git.kernel.org/?p=linux/kernel/git/hjl/linux-2.6.38.y.git;a=summary H.J. --- > -----Original Message----- > From: H.J. Lu [hjl.to...@gmail.com] > Sent: Saturday, May 21, 2011 12:39 PM Pacific Standard Time > To: Anvin, H Peter > Cc: x32-...@googlegroups.com; Arnd Bergmann; GCC Development; GNU C Library; > LKML > Subject: Re: X32 project status update > > On Sat, May 21, 2011 at 11:55 AM, H. Peter Anvin > <h.peter.an...@intel.com> wrote: >> On 05/21/2011 09:27 AM, H.J. Lu wrote: >>> On Sat, May 21, 2011 at 8:34 AM, H.J. Lu <hjl.to...@gmail.com> wrote: >>>> On Sat, May 21, 2011 at 8:27 AM, Arnd Bergmann <a...@arndb.de> wrote: >>>>> On Saturday 21 May 2011 17:01:33 H.J. Lu wrote: >>>>>> This is the x32 project status update: >>>>>> >>>>>> https://sites.google.com/site/x32abi/ >>>>>> >>>>> >>>>> I've had another look at the kernel patch. It basically >>>>> looks all good, but the system call table appears to >>>>> diverge from the x86_64 list for no (documented) reason, >>>>> in the calls above 302. Is that intentional? >>>>> >>>>> I can see why you might want to keep the numbers identical, >>>>> but if they are already different, why not use the generic >>>>> system call table from asm-generic/unistd.h for the new >>>>> ABI? >>>> >>>> We can sort it out when we start merging x32 kernel changes. >>>> >>> >>> Peter, is that possible to use the single syscall table for >>> both x86-64 and x32 system calls? Out of 300+ system >>> calls, only 84 are different for x86-64 and x32. That >>> is additional 8*84 == 672 bytes in syscall table. >>> >> >> Sort of... remember we talked about merging system calls at the tail >> end? The problem with that is that some system calls (like read()!) >> actually are different system calls in very subtle situations, due to >> abuse in some subsystems of the is_compat() construct. I think that may >> mean we have to have an unambiguous flag after all... >> >> Now, perhaps we can use a high bit for that and mask it before dispatch, >> then we don't need the additional table. A bit of a hack, but it should >> work. > > How about this patch? > > Merge x32 system calls with x86-64 system calls > > Implemented with > > 1. Mark all x86-64 specific system calls with __NR_64_. > 2. Mark all x32 specific system calls with __NR_x32_. > 3. Include unistd_64_compat.h, instead of unistd_x32.h for kernel > build, which provides __NR_ versions of x86-64 specific system calls. > 4. Append x32 specific system calls after the current x86-64 system > calls. > 5. Generate unistd_x32.h from unistd_64.h, replacing __NR_x32_ with > _NR_. > 6. Install user-space unistd_64.h, replacing __NR_64_ with _NR_. > > -- > H.J. > -- H.J.
