1. 12 3月, 2015 4 次提交
    • S
      add aarch64 port · 01ef3dd9
      Szabolcs Nagy 提交于
      This adds complete aarch64 target support including bigendian subarch.
      
      Some of the long double math functions are known to be broken otherwise
      interfaces should be fully functional, but at this point consider this
      port experimental.
      
      Initial work on this port was done by Sireesh Tripurari and Kevin Bortis.
      01ef3dd9
    • S
      math: add dummy implementations of 128 bit long double functions · f4e4632a
      Szabolcs Nagy 提交于
      This is in preparation for the aarch64 port only to have the long
      double math symbols available on ld128 platforms. The implementations
      should be fixed up later once we have proper tests for these functions.
      
      Added bigendian handling for ld128 bit manipulations too.
      f4e4632a
    • S
      math: add ld128 exp2l based on the freebsd implementation · 53cfe0c6
      Szabolcs Nagy 提交于
      Changed the special case handling and bit manipulation to better
      match the double version.
      53cfe0c6
    • S
      copy the dtv pointer to the end of the pthread struct for TLS_ABOVE_TP archs · 204a69d2
      Szabolcs Nagy 提交于
      There are two main abi variants for thread local storage layout:
      
       (1) TLS is above the thread pointer at a fixed offset and the pthread
       struct is below that. So the end of the struct is at known offset.
      
       (2) the thread pointer points to the pthread struct and TLS starts
       below it. So the start of the struct is at known (zero) offset.
      
      Assembly code for the dynamic TLSDESC callback needs to access the
      dynamic thread vector (dtv) pointer which is currently at the front
      of the pthread struct. So in case of (1) the asm code needs to hard
      code the offset from the end of the struct which can easily break if
      the struct changes.
      
      This commit adds a copy of the dtv at the end of the struct. New members
      must not be added after dtv_copy, only before it. The size of the struct
      is increased a bit, but there is opportunity for size optimizations.
      204a69d2
  2. 08 3月, 2015 2 次提交
  3. 07 3月, 2015 1 次提交
    • R
      fix over-alignment of TLS, insufficient builtin TLS on 64-bit archs · bd67959f
      Rich Felker 提交于
      a conservative estimate of 4*sizeof(size_t) was used as the minimum
      alignment for thread-local storage, despite the only requirements
      being alignment suitable for struct pthread and void* (which struct
      pthread already contains). additional alignment required by the
      application or libraries is encoded in their headers and is already
      applied.
      
      over-alignment prevented the builtin_tls array from ever being used in
      dynamic-linked programs on 64-bit archs, thereby requiring allocation
      at startup even in programs with no TLS of their own.
      bd67959f
  4. 05 3月, 2015 7 次提交
  5. 04 3月, 2015 4 次提交
    • R
      remove useless check of bin match in malloc · 064898cf
      Rich Felker 提交于
      this re-check idiom seems to have been copied from the alloc_fwd and
      alloc_rev functions, which guess a bin based on non-synchronized
      memory access to adjacent chunk headers then need to confirm, after
      locking the bin, that the chunk is actually in the bin they locked.
      
      the check being removed, however, was being performed on a chunk
      obtained from the already-locked bin. there is no race to account for
      here; the check could only fail in the event of corrupt free lists,
      and even then it would not catch them but simply continue running.
      
      since the bin_index function is mildly expensive, it seems preferable
      to remove the check rather than trying to convert it into a useful
      consistency check. casual testing shows a 1-5% reduction in run time.
      064898cf
    • R
      eliminate atomics in syslog setlogmask function · 6de071a0
      Rich Felker 提交于
      6de071a0
    • R
      fix init race that could lead to deadlock in malloc init code · 7a81fe37
      Rich Felker 提交于
      the malloc init code provided its own version of pthread_once type
      logic, including the exact same bug that was fixed in pthread_once in
      commit 0d0c2f40.
      
      since this code is called adjacent to expand_heap, which takes a lock,
      there is no reason to have pthread_once-type initialization. simply
      moving the init code into the interval where expand_heap already holds
      its lock on the brk achieves the same result with much less
      synchronization logic, and allows the buggy code to be eliminated
      rather than just fixed.
      7a81fe37
    • R
      make all objects used with atomic operations volatile · 56fbaa3b
      Rich Felker 提交于
      the memory model we use internally for atomics permits plain loads of
      values which may be subject to concurrent modification without
      requiring that a special load function be used. since a compiler is
      free to make transformations that alter the number of loads or the way
      in which loads are performed, the compiler is theoretically free to
      break this usage. the most obvious concern is with atomic cas
      constructs: something of the form tmp=*p;a_cas(p,tmp,f(tmp)); could be
      transformed to a_cas(p,*p,f(*p)); where the latter is intended to show
      multiple loads of *p whose resulting values might fail to be equal;
      this would break the atomicity of the whole operation. but even more
      fundamental breakage is possible.
      
      with the changes being made now, objects that may be modified by
      atomics are modeled as volatile, and the atomic operations performed
      on them by other threads are modeled as asynchronous stores by
      hardware which happens to be acting on the request of another thread.
      such modeling of course does not itself address memory synchronization
      between cores/cpus, but that aspect was already handled. this all
      seems less than ideal, but it's the best we can do without mandating a
      C11 compiler and using the C11 model for atomics.
      
      in the case of pthread_once_t, the ABI type of the underlying object
      is not volatile-qualified. so we are assuming that accessing the
      object through a volatile-qualified lvalue via casts yields volatile
      access semantics. the language of the C standard is somewhat unclear
      on this matter, but this is an assumption the linux kernel also makes,
      and seems to be the correct interpretation of the standard.
      56fbaa3b
  6. 03 3月, 2015 4 次提交
  7. 28 2月, 2015 1 次提交
    • R
      fix failure of internal futex __timedwait to report ECANCELED · 76ca7a54
      Rich Felker 提交于
      as part of abstracting the futex wait, this function suppresses all
      futex error values which callers should not see using a whitelist
      approach. when the masked cancellation mode was added, the new
      ECANCELED error was not whitelisted. this omission caused the new
      pthread_cond_wait code using masked cancellation to exhibit a spurious
      wake (rather than acting on cancellation) when the request arrived
      after blocking on the cond var.
      76ca7a54
  8. 26 2月, 2015 3 次提交
    • R
      overhaul optimized x86_64 memset asm · e346ff86
      Rich Felker 提交于
      on most cpu models, "rep stosq" has high overhead that makes it
      undesirable for small memset sizes. the new code extends the
      minimal-branch fast path for short memsets from size 15 up to size
      126, and shrink-wraps this code path. in addition, "rep stosq" is
      sensitive to misalignment. the cost varies with size and with cpu
      model, but it has been observed performing 1.5 times slower when the
      destination address is not aligned mod 16. the new code thus ensures
      alignment mod 16, but also preserves any existing additional
      alignment, in case there are cpu models where it is beneficial.
      
      this version is based in part on changes proposed by Denys Vlasenko.
      e346ff86
    • R
      overhaul optimized i386 memset asm · 69858fa9
      Rich Felker 提交于
      on most cpu models, "rep stosl" has high overhead that makes it
      undesirable for small memset sizes. the new code extends the
      minimal-branch fast path for short memsets from size 15 up to size 62,
      and shrink-wraps this code path. in addition, "rep stosl" is very
      sensitive to misalignment. the cost varies with size and with cpu
      model, but it has been observed performing 1.5 to 4 times slower when
      the destination address is not aligned mod 16. the new code thus
      ensures alignment mod 16, but also preserves any existing additional
      alignment, in case there are cpu models where it is beneficial.
      
      this version is based in part on changes to the x86_64 memset asm
      proposed by Denys Vlasenko.
      69858fa9
    • A
      getloadavg: use sysinfo() instead of /proc/loadavg · 20cbd607
      Alexander Monakov 提交于
      Based on a patch by Szabolcs Nagy.
      20cbd607
  9. 24 2月, 2015 2 次提交
    • R
      fix possible isatty false positives and unwanted device state changes · 2de85a98
      Rich Felker 提交于
      the equivalent checks for newly opened stdio output streams, used to
      determine buffering mode, are also fixed.
      
      on most archs, the TCGETS ioctl command shares a value with
      SNDCTL_TMR_TIMEBASE, part of the OSS sound API which was apparently
      used with certain MIDI and timer devices. for file descriptors
      referring to such a device, TCGETS will not fail with ENOTTY as
      expected; it may produce a different error, or may succeed, and if it
      succeeds it changes the mode of the device. while it's unlikely that
      such devices are in use, this is in principle very harmful behavior
      for an operation which is supposed to do nothing but query whether the
      fd refers to a tty.
      
      TIOCGWINSZ, used to query logical window size for a terminal, was
      chosen as an alternate ioctl to perform the isatty check. it does not
      share a value with any other ioctl commands, and it succeeds on any
      tty device.
      
      this change also cleans up strace output to be less ugly and
      misleading.
      2de85a98
    • R
      fix breakage in pthread_cond_wait due to typo · e487c203
      Rich Felker 提交于
      due to accidental use of = instead of ==, the error code was always
      set to zero in the signaled wake case for non-shared cv waits.
      suppressing ETIMEDOUT (the only possible wait error) is harmless and
      actually permitted in this case, but suppressing mutex errors could
      give the caller false information about the state of the mutex.
      
      commit 8741ffe6 introduced this
      regression and commit d9da1fb8
      preserved it when reorganizing the code.
      e487c203
  10. 23 2月, 2015 5 次提交
    • J
      support alternate backends for the passwd and group dbs · 34b423d2
      Josiah Worcester 提交于
      when we fail to find the entry in the commonly accepted files,  we
      query a server over a Unix domain socket on /var/run/nscd/socket.
      the protocol used here is compatible with glibc's nscd protocol on
      most systems (all that use 32-bit numbers for all the protocol fields,
      which appears to be everything but Alpha).
      34b423d2
    • R
      fix spurious errors in refactored passwd/group code · 0afef1aa
      Rich Felker 提交于
      errno was treated as the error status when the return value of getline
      was negative, but this condition can simply indicate EOF and is not
      necessarily an error.
      
      the spurious errors caused by this bug masked the bug which was fixed
      in commit fc5a96c9.
      0afef1aa
    • R
      fix crashes in refactored passwd/group code · fc5a96c9
      Rich Felker 提交于
      the wrong condition was used in determining the presence of a result
      that needs space/copying for the _r functions. a zero return value
      does not necessarily mean success; it can also be a non-error negative
      result: no such user/group.
      fc5a96c9
    • R
      d9da1fb8
    • R
      fix pthread_cond_wait cancellation race · 8741ffe6
      Rich Felker 提交于
      it's possible that signaling a waiter races with cancellation of that
      same waiter. previously, cancellation was acted upon, causing the
      signal to be consumed with no waiter returning. by using the new
      masked cancellation state, it's possible to refuse to act on the
      cancellation request and instead leave it pending.
      
      to ease review and understanding of the changes made, this commit
      leaves the unwait function, which was previously the cancellation
      cleanup handler, in place. additional simplifications could be made by
      removing it.
      8741ffe6
  11. 22 2月, 2015 1 次提交
    • R
      add new masked cancellation mode · 102f6a01
      Rich Felker 提交于
      this is a new extension which is presently intended only for
      experimental and internal libc use. interface and behavior details may
      change subject to feedback and experience from using it internally.
      
      the basic concept for the new PTHREAD_CANCEL_MASKED state is that the
      first cancellation point to observe the cancellation request fails
      with an errno value of ECANCELED rather than acting on cancellation,
      allowing the caller to process the status and choose whether/how to
      act upon it.
      102f6a01
  12. 21 2月, 2015 2 次提交
  13. 17 2月, 2015 1 次提交
  14. 15 2月, 2015 1 次提交
    • R
      fix type error (arch-dependent) in new aio code · fd850de7
      Rich Felker 提交于
      a_store is only valid for int, but ssize_t may be defined as long or
      another type. since there is no valid way for another thread to acess
      the return value without first checking the error/completion status of
      the aiocb anyway, an atomic store is not necessary.
      fd850de7
  15. 13 2月, 2015 2 次提交
    • J
      refactor group file access code · 7c5f0a52
      Josiah Worcester 提交于
      this allows getgrnam and getgrgid to share code with the _r versions
      in preparation for alternate backend support.
      7c5f0a52
    • R
      overhaul aio implementation for correctness · 4e8a3561
      Rich Felker 提交于
      previously, aio operations were not tracked by file descriptor; each
      operation was completely independent. this resulted in non-conforming
      behavior for non-seekable/append-mode writes (which are required to be
      ordered) and made it impossible to implement aio_cancel, which in turn
      made closing file descriptors with outstanding aio operations unsafe.
      
      the new implementation is significantly heavier (roughly twice the
      size, and seems to be slightly slower) and presently aims mainly at
      correctness, not performance.
      
      most of the public interfaces have been moved into a single file,
      aio.c, because there is little benefit to be had from splitting them.
      whenever any aio functions are used, aio_cancel and the internal
      queue lifetime management and fd-to-queue mapping code must be linked,
      and these functions make up the bulk of the code size.
      
      the close function's interaction with aio is implemented with weak
      alias magic, to avoid pulling in heavy aio cancellation code in
      programs that don't use aio, and the expensive cancellation path
      (which includes signal blocking) is optimized out when there are no
      active aio queues.
      4e8a3561