Bug #60925 [Asn->Ana]: fpm_atomic.h says unknown processor (m68k)

Edit report at https://bugs.php.net/bug.php?id=60925&edit=1 ID: 60925 Updated by: kalle@php.net Reported by: tg at debian dot org Summary: fpm_atomic.h says unknown processor (m68k) -Status: Assigned +Status: Analyzed Type: Bug Package: FPM related Operating System: Linux PHP Version: 5.4 -Assigned To: tony2001 +Assigned To: Block user comment: N Private report: N Previous Comments: ------------------------------------------------------------------------ [2012-04-16 18:31:28] tg at debian dot org Make of this patch what you want. I’ve not gotten anything from the Linux/m68k porters other than “what do you do if the syscall does not exist?” with no solution. (On the other hand, it exists with every Linux kernel from 2.6.34 onwards or Debian 2.6.32; and older systems won’t support the last few eglibc major releases anyway, so chances are low someone’s trying PHP on such systems. And the patch keeps the #error for non-Linux systems.) ------------------------------------------------------------------------ [2012-03-12 23:31:51] tg at debian dot org I’ve built 5.4.0 with a small patch. We’re working on getting it usable for upstream inclusion. On Linux/m68k, one uses a syscall for compare-and-swap 32 bit, as some CPUs do not support the machine instruction and probing for it is too tricky in user space. The syscall was introduced along with TLS support, now we probably need to safeguard this from being compiled on “too old” Linux systems. The patch doesn’t address nōn-Linux m68k, as those are different beasts, and see above. (The ColdFire does not support the instruction, and Linux and MiNT may very well both run on one with MMU, soonish.) ------------------------------------------------------------------------ [2012-02-02 20:11:39] tg at debian dot org OK; in the meantime I’ll try building without FPM, to see whether there are any other lurking issues on m68k. Thanks for the help with this. ------------------------------------------------------------------------ [2012-01-31 00:50:00] aharvey@php.net Thanks again. It's been good to triage this down. :) I'll let Jérôme figure out what he wants to do here, since he's the FPM maintainer. I think your list of options pretty much covers it. ------------------------------------------------------------------------ [2012-01-31 00:39:53] tg at debian dot org Heh, your comment made me go and read the old changelogs of the Debian package on a guess, and I guessed right: php5 (5.3.5-1) unstable; urgency=low * Build the FPM SAPI (Closes: #603174) So this was simply never built before. Now there are two possibilities, disable FPM on m68k (unless gcc-4.7 or up is used) or ask the m68k porters for an implementation of the atomic things. I think. If you’ve got a better idea, do tell. By the way, there’s libatomic-ops-dev, which contains a number of atomic primitives and composed operations on a number of data types (but the catch is, you’ve got to use the data types of libatomic-ops-dev, not e.g. like mesa have a function atomic_dec which is passed an int32_t* so it’s not a plug-in replacement. That might be more interesting than hacking in m68k support now, and support for $next_arch later… m68k atomic operations apparently have another twist: the compare-and-swap operation only exists on some processors, and not in the Coldfire line, so the Linux kernel got a syscall now to ensure atomicity. GCC 4.7 uses the syscall; most “inlined” application code doesn’t… ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=60925 -- Edit this bug report at https://bugs.php.net/bug.php?id=60925&edit=1