Bug #60925 [Opn]: fpm_atomic.h says unknown processor (m68k)

Edit report at https://bugs.php.net/bug.php?id=60925&edit=1 ID: 60925 User updated by: tg at debian dot org Reported by: tg at debian dot org Summary: fpm_atomic.h says unknown processor (m68k) Status: Open Type: Bug Package: FPM related Operating System: Linux PHP Version: 5.3.9 Block user comment: N Private report: N New Comment: 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.) Previous Comments: ------------------------------------------------------------------------ [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… ------------------------------------------------------------------------ [2012-01-31 00:06:52] aharvey@php.net Ah, I didn't know that, so no, no need on the vanilla tarball front. Thanks! The fix here would be a patch for fpm_atomic.h implementing the same atomic functions for m68k as the other fallback platforms in there, such as x86 and SPARC v9. I'm not actually sure why 5.3.3-7 built at all, actually -- the only patch it had over stock 5.3.3 (which had no support at all for m68k) was implementing support for __sync_bool_compare_and_swap() if it existed, so it should have failed with the same #error. Interesting. ------------------------------------------------------------------------ [2012-01-30 16:52:13] tg at debian dot org configure:12302: checking if gcc supports __sync_bool_compare_and_swap configure:12319: m68k-linux-gnu-gcc -o conftest -O2 -Wall -fsigned-char -fno-strict-aliasing -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -gstabs -fvisibility=hidden conftest.c -lrt >&5 /tmp/ccmCFUbp.o: In function `main': conftest.c:48: undefined reference to `__sync_bool_compare_and_swap_4' conftest.c:49: undefined reference to `__sync_add_and_fetch_4' collect2: ld returned 1 exit status configure:12319: $? = 1 configure: failed program was: | /* confdefs.h */ | #define PACKAGE_NAME "" | #define PACKAGE_TARNAME "" | #define PACKAGE_VERSION "" | #define PACKAGE_STRING "" | #define PACKAGE_BUGREPORT "" | #define PACKAGE_URL "" | #define STDC_HEADERS 1 | #define HAVE_SYS_TYPES_H 1 | #define HAVE_SYS_STAT_H 1 | #define HAVE_STDLIB_H 1 | #define HAVE_STRING_H 1 | #define HAVE_MEMORY_H 1 | #define HAVE_STRINGS_H 1 | #define HAVE_INTTYPES_H 1 | #define HAVE_STDINT_H 1 | #define HAVE_UNISTD_H 1 | #define __EXTENSIONS__ 1 | #define _ALL_SOURCE 1 | #define _GNU_SOURCE 1 | #define _POSIX_PTHREAD_SEMANTICS 1 | #define _TANDEM_SOURCE 1 | #define HAVE_DEV_URANDOM 1 | #define HAVE_SETENV 1 | #define HAVE_CLEARENV 1 | #define HAVE_ERRNO_H 1 | #define HAVE_FCNTL_H 1 | #define HAVE_STDIO_H 1 | #define HAVE_STDLIB_H 1 | #define HAVE_UNISTD_H 1 | #define HAVE_SYS_UIO_H 1 | #define HAVE_SYS_SELECT_H 1 | #define HAVE_SYS_SOCKET_H 1 | #define HAVE_SYS_TIME_H 1 | #define HAVE_ARPA_INET_H 1 | #define HAVE_NETINET_IN_H 1 | #define HAVE_PRCTL 1 | #define HAVE_CLOCK_GETTIME 1 | #define HAVE_PTRACE 1 | #define PROC_MEM_FILE "mem" | /* end confdefs.h. */ | | int | main () | { | | int variable = 1; | return (__sync_bool_compare_and_swap(&variable, 1, 2) | && __sync_add_and_fetch(&variable, 1)) ? 1 : 0; | | ; | return 0; | } configure:12329: result: no ------------------------------------------------------------------------ The remainder of the comments for this report are too long. 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