I'll look at it but possibly not until the weekend. -----Original Message----- From: H.J. Lu [hjl.to...@gmail.com<mailto: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.
