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2013-09-23release notes for 0.9.14v0.9.14Rich Felker-0/+30
2013-09-22fix arm atomic store and generate simpler/less-bloated/faster codeRich Felker-6/+8
atomic store was lacking a barrier, which was fine for legacy arm with no real smp and kernel-emulated cas, but unsuitable for more modern systems. the kernel provides another "kuser" function, at 0xffff0fa0, which could be used for the barrier, but using that would drop support for kernels 2.6.12 through 2.6.14 unless an extra conditional were added to check for barrier availability. just using the barrier in the kernel cas is easier, and, based on my reading of the assembly code in the kernel, does not appear to be significantly slower. at the same time, other atomic operations are adapted to call the kernel cas function directly rather than using a_cas; due to small differences in their interface contracts, this makes the generated code much simpler.
2013-09-20fix potential deadlock bug in libc-internal locking logicRich Felker-13/+15
if a multithreaded program became non-multithreaded (i.e. all other threads exited) while one thread held an internal lock, the remaining thread would fail to release the lock. the the program then became multithreaded again at a later time, any further attempts to obtain the lock would deadlock permanently. the underlying cause is that the value of libc.threads_minus_1 at unlock time might not match the value at lock time. one solution would be returning a flag to the caller indicating whether the lock was taken and needs to be unlocked, but there is a simpler solution: using the lock itself as such a flag. note that this flag is not needed anyway for correctness; if the lock is not held, the unlock code is harmless. however, the memory synchronization properties associated with a_store are costly on some archs, so it's best to avoid executing the unlock code when it is unnecessary.
2013-09-20correct the sysconf value for RTSIG_MAXRich Felker-1/+2
this is the number of realtime signals available, not the maximum signal number or total number of signals.
2013-09-16fix sigemptyset and sigfillset for mipsRich Felker-1/+10
they were leaving junk in the upper bits.
2013-09-16fix clobbering of caller's stack in mips __clone functionRich Felker-0/+3
this was resulting in crashes in posix_spawn on mips, and would have affected applications calling clone too. since the prototype for __clone has it as a variadic function, it may not assume that 16($sp) is writable for use in making the syscall. instead, it needs to allocate additional stack space, and then adjust the stack pointer back in both of the code paths for the parent process/thread.
2013-09-16sys/resource.h: add PRIO_MIN and PRIO_MAX for getpriority and setprioritySzabolcs Nagy-0/+3
These constants are not specified by POSIX, but they are in the reserved namespace, glibc and bsd systems seem to provide them as well. (Note that POSIX specifies -NZERO and NZERO-1 to be the limits, but PRIO_MAX equals NZERO)
2013-09-16update include/elf.h following glibc changesSzabolcs Nagy-27/+143
the changes were verified using various sources: linux: include/uapi/linux/elf.h binutils: include/elf/common.h glibc: elf/elf.h sysv gabi: sun linker docs: and platform specific docs - fixed: EF_MIPS_* E_MIPS_* e_flags: fixed accoding to glibc and binutils - added: ELFOSABI_GNU for EI_OSABI entry: glibc, binutils and sysv gabi EM_* e_machine values: updated according to linux and glibc PN_XNUM e_phnum value: from glibc and linux, see oracle docs NT_* note types: updated according to linux and glibc DF_1_* flags for DT_FLAGS_1 entry: following glibc and oracle docs AT_HWCAP2 auxv entry for more hwcap bits accoding to linux and glibc R_386_SIZE32 relocation according to glibc and binutils EF_ARM_ABI_FLOAT_* e_flags: added following glibc and binutils R_AARCH64_* relocs: added following glibc and aarch64 elf specs R_ARM_* relocs: according to glibc, binutils and arm elf specs R_X86_64_* relocs: added missing relocs following glibc - removed: HWCAP_SPARC_* flags were moved to arch specific header in glibc R_ARM_SWI24 reloc is marked as obsolete in glibc, not present in binutils not specified in arm elf spec, R_ARM_TLS_DESC reused its number see - glibc changes not pulled in: ELFOSABI_ARM_AEABI (bare-metal system, binutils and glibc disagrees about the name) R_68K_* relocs for unsupported platform R_SPARC_* ditto EF_SH* ditto (e_flags) EF_S390* ditto (e_flags) R_390* ditto R_MN10300* ditto R_TILE* ditto
2013-09-16omit CLONE_PARENT flag to clone in pthread_createRich Felker-1/+1
CLONE_PARENT is not necessary (CLONE_THREAD provides all the useful parts of it) and Linux treats CLONE_PARENT as an error in certain situations, without noticing that it would be a no-op due to CLONE_THREAD. this error case prevents, for example, use of a multi-threaded init process and certain usages with containers.
2013-09-16use symbolic names for clone flags in pthread_createRich Felker-2/+5
2013-09-15sys/socket.h: add new SO_BUSY_POLL socket optionSzabolcs Nagy-0/+1
low latency busy poll sockets are new in linux v3.11
2013-09-15ptrace.h: add new ptrace requests to get/set sigmaskSzabolcs Nagy-0/+2
PTRACE_GETSIGMASK and PTRACE_SETSIGMASK were added in linux v3.11 and used by checkpoint/restore tools
2013-09-15net/if_arp.h: add missing ARP hardware identifiers from linux uapi headersSzabolcs Nagy-1/+7
the removed ARPHRD_IEEE802154_PHY was only present in the kernel api in v2.6.31 (by accident), but it got into the glibc headers (in 2009) and remained there since this header was not updated since then.
2013-09-15netinet/in.h: add missing IP protocol numbers from the linux uapi headersSzabolcs Nagy-0/+2
2013-09-15support configurable page size on mips, powerpc and microblazeSzabolcs Nagy-17/+29
PAGE_SIZE was hardcoded to 4096, which is historically what most systems use, but on several archs it is a kernel config parameter, user space can only know it at execution time from the aux vector. PAGE_SIZE and PAGESIZE are not defined on archs where page size is a runtime parameter, applications should use sysconf(_SC_PAGE_SIZE) to query it. Internally libc code defines PAGE_SIZE to libc.page_size, which is set to aux[AT_PAGESZ] in __init_libc and early in __dynlink as well. (Note that libc.page_size can be accessed without GOT, ie. before relocations are done) Some fpathconf settings are hardcoded to 4096, these should be actually queried from the filesystem using statfs.
2013-09-14fix overflow in sysconf for _SC_MQ_PRIO_MAXRich Felker-1/+2
the value of MQ_PRIO_MAX does not fit, so it needs to use OFLOW.
2013-09-14fix child stack alignment on mips cloneRich Felker-0/+1
unlike other archs, the mips version of clone was not doing anything to align the stack pointer. this seems to have been the cause for some SIGBUS crashes that were observed in posix_spawn.
2013-09-14fix mips sysv ipc bits headersRich Felker-3/+9
msg.h was wrong for big-endian (wrong endiannness padding). shm.h was just plain wrong (mips is not supposed to have padding). both changes were tested using libc-test on qemu-system-mips.
2013-09-13fix x86_64 lrintl asm, againRich Felker-2/+2
the underlying problem was not incorrect sign extension (fixed in the previous commit to this file by nsz) but that code that treats "long" as 32-bit was copied blindly from i386 to x86_64. now lrintl is identical to llrintl on x86_64, as it should be.
2013-09-09do not use default when dynamic linker fails to open existing path fileRich Felker-0/+2
if fopen fails for a reason other than ENOENT, we must assume the intent is that the path file be used. failure may be due to misconfiguration or intentional resource-exhaustion attack (against suid programs), in which case falling back to loading libraries from an unintended path could be dangerous.
2013-09-06math: remove STRICT_ASSIGN from exp2f (see previous commit)Szabolcs Nagy-1/+1
2013-09-06math: remove STRICT_ASSIGN macroSzabolcs Nagy-23/+13
gcc did not always drop excess precision according to c99 at assignments before version 4.5 even if -std=c99 was requested which caused badly broken mathematical functions on i386 when FLT_EVAL_METHOD!=0 but STRICT_ASSIGN was not used consistently and it is worked around for old compilers with -ffloat-store so it is no longer needed the new convention is to get the compiler respect c99 semantics and when excess precision is not harmful use float_t or double_t or to specialize code using FLT_EVAL_METHOD
2013-09-05math: support invalid ld80 representations in fpclassifySzabolcs Nagy-2/+4
apparently gnulib requires invalid long double representations to be handled correctly in printf so we classify them according to how the fpu treats them: bad inf is nan, bad nan is nan, bad normal is nan and bad subnormal/zero is minimal normal
2013-09-05math: fix atanh (overflow and underflow issues)Szabolcs Nagy-14/+37
in atanh exception handling was left to the called log functions, but the argument to those functions could underflow or overflow. use double_t and float_t to avoid some useless stores on x86
2013-09-05math: remove libc.h include from libm.hSzabolcs Nagy-3/+5
libc.h is only for weak_alias so include it directly where it is used
2013-09-05math: fix acoshf on negative valuesSzabolcs Nagy-7/+8
acosh(x) is invalid for x<1, acoshf tried to be clever using signed comparisions to handle all x<2 the same way, but the formula was wrong on large negative values.
2013-09-05math: fix expm1l on x86_64 (avoid underflow for large negative x)Szabolcs Nagy-3/+13
copy the fix from i386: return -1 instead of exp2l(x)-1 when x <= -65
2013-09-05math: fix lrintl.s on x86_64 (use movslq to signextend the result)Szabolcs Nagy-1/+1
2013-09-05math: fix exp2l asm on x86 (raise underflow correctly)Szabolcs Nagy-67/+78
there were two problems: * omitted underflow on subnormal results: exp2l(-16383.5) was calculated as sqrt(2)*2^-16384, the last bits of sqrt(2) are zero so the down scaling does not underflow eventhough the result is in subnormal range * spurious underflow for subnormal inputs: exp2l(0x1p-16400) was evaluated as f2xm1(x)+1 and f2xm1 raised underflow (because inexact subnormal result) the first issue is fixed by raising underflow manually if x is in (-32768,-16382] and not integer (x-0x1p63+0x1p63 != x) the second issue is fixed by treating x in (-0x1p64,0x1p64) specially for these fixes the special case handling was completely rewritten
2013-09-05math: cosmetic cleanup (use explicit union instead of fshape and dshape)Szabolcs Nagy-166/+140
2013-09-05math: remove *_WORD64 macros from libm.hSzabolcs Nagy-29/+13
only fma used these macros and the explicit union is clearer
2013-09-05math: remove old longdbl.hSzabolcs Nagy-113/+0
2013-09-05math: long double fix (use ldshape union)Szabolcs Nagy-51/+24
* use new ldshape union consistently * add ld128 support to frexpl * simplify sqrtl comment (ld64 is not just arm)
2013-09-05math: use float_t and double_t in scalbnf and scalbnSzabolcs Nagy-16/+20
remove STRICT_ASSIGN (c99 semantics is assumed) and use the conventional union to prepare the scaling factor (so libm.h is no longer needed)
2013-09-05math: fix remaining old long double code (erfl, fmal, lgammal, scalbnl)Szabolcs Nagy-93/+65
in lgammal don't handle 1 and 2 specially, in fma use the new ldshape union instead of ld80 one.
2013-09-05math: cbrt cleanup and long double fixSzabolcs Nagy-72/+59
* use float_t and double_t * cleanup subnormal handling * bithacks according to the new convention (ldshape for long double and explicit unions for float and double)
2013-09-05math: fix underflow in exp*.c and long double handling in exp2lSzabolcs Nagy-182/+139
* don't care about inexact flag * use double_t and float_t (faster, smaller, more precise on x86) * exp: underflow when result is zero or subnormal and not -inf * exp2: underflow when result is zero or subnormal and not exact * expm1: underflow when result is zero or subnormal * expl: don't underflow on -inf * exp2: fix incorrect comment * expm1: simplify special case handling and overflow properly * expm1: cleanup final scaling and fix negative left shift ub (twopk)
2013-09-05math: long double trigonometric cleanup (cosl, sinl, sincosl, tanl)Szabolcs Nagy-236/+228
ld128 support was added to internal kernel functions (__cosl, __sinl, __tanl, __rem_pio2l) from freebsd (not tested, but should be a good start for when ld128 arch arrives) __rem_pio2l had some code cleanup, the freebsd ld128 code seems to gather the results of a large reduction with precision loss (fixed the bug but a todo comment was added for later investigation) the old copyright was removed from the non-kernel wrapper functions (cosl, sinl, sincosl, tanl) since these are trivial and the interesting parts and comments had been already rewritten.
2013-09-05math: long double inverse trigonometric cleanup (acosl, asinl, atanl, atan2l)Szabolcs Nagy-103/+180
* added ld128 support from freebsd fdlibm (untested) * using new ldshape union instead of IEEEl2bits * inexact status flag is not supported
2013-09-05math: rewrite hypotSzabolcs Nagy-324/+135
method: if there is a large difference between the scale of x and y then the larger magnitude dominates, otherwise reduce x,y so the argument of sqrt (x*x+y*y) does not overflow or underflow and calculate the argument precisely using exact multiplication. If the argument has less error than 1/sqrt(2) ~ 0.7 ulp, then the result has less error than 1 ulp in nearest rounding mode. the original fdlibm method was the same, except it used bit hacks instead of dekker-veltkamp algorithm, which is problematic for long double where different representations are supported. (the new hypot and hypotl code should be smaller and faster on 32bit cpu archs with fast fpu), the new code behaves differently in non-nearest rounding, but the error should be still less than 2ulps. ld80 and ld128 are supported
2013-09-05math: rewrite remainder functions (remainder, remquo, fmod, modf)Szabolcs Nagy-1010/+472
* results are exact * modfl follows truncl (raises inexact flag spuriously now) * modf and modff only had cosmetic cleanup * remainder is just a wrapper around remquo now * using iterative shift+subtract for remquo and fmod * ld80 and ld128 are supported as well
2013-09-05math: rewrite rounding functions (ceil, floor, trunc, round, rint)Szabolcs Nagy-905/+274
* faster, smaller, cleaner implementation than the bit hacks of fdlibm * use arithmetics like y=(double)(x+0x1p52)-0x1p52, which is an integer neighbor of x in all rounding modes (0<=x<0x1p52) and only use bithacks when that's faster and smaller (for float it usually is) * the code assumes standard excess precision handling for casts * long double code supports both ld80 and ld128 * nearbyint is not changed (it is a wrapper around rint)
2013-09-05math: fix logb(-0.0) in downward rounding modeSzabolcs Nagy-6/+6
use -1/(x*x) instead of -1/(x+0) to return -inf, -0+0 is -0 in downward rounding mode
2013-09-05math: ilogb cleanupSzabolcs Nagy-16/+43
* consistent code style * explicit union instead of typedef for double and float bit access * turn FENV_ACCESS ON to make 0/0.0f raise invalid flag * (untested) ld128 version of ilogbl (used by logbl which has ld128 support)
2013-09-05long double cleanup, initial commitSzabolcs Nagy-96/+89
new ldshape union, ld128 support is kept, code that used the old ldshape union was rewritten (IEEEl2bits union of freebsd libm is not touched yet) ld80 __fpclassifyl no longer tries to handle invalid representation
2013-09-04fix typo in comment in __randnameRich Felker-1/+1
2013-09-02fix mips-specific bug in synccall (too little space for signal mask)Rich Felker-5/+3
switch to the new __block_all_sigs/__restore_sigs internal API to clean up the code too.
2013-09-02in synccall, ignore the signal before any threads' signal handlers returnRich Felker-4/+4
this protects against deadlock from spurious signals (e.g. sent by another process) arriving after the controlling thread releases the other threads from the sync operation.
2013-09-02fix invalid pointer in synccall (multithread setuid, etc.)Rich Felker-0/+1
the head pointer was not being reset between calls to synccall, so any use of this interface more than once would build the linked list incorrectly, keeping the (now invalid) list nodes from the previous call.
2013-09-01fix special-case breakage in popen due to reversed argument orderRich Felker-1/+1