- 18 8月, 2020 1 次提交
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由 Rich Felker 提交于
this is a prerequisite for addition of other interfaces that use kernel tids, including futex and SIGEV_THREAD_ID. there is some ambiguity as to whether the semantic return type should be int or pid_t. either way, futex API imposes a contract that the values fit in int (excluding some upper reserved bits). glibc used pid_t, so in the interest of not having gratuitous mismatch (the underlying types are the same anyway), pid_t is used here as well. while conceptually this is a syscall, the copy stored in the thread structure is always valid in all contexts where it's valid to call libc functions, so it's used to avoid the syscall.
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- 13 8月, 2020 2 次提交
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由 Szabolcs Nagy 提交于
longjmp should set the return value of setjmp, but 64bit registers were used for the 0 check while the type is int. use the code that gcc generates for return val ? val : 1;
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由 Alexander Monakov 提交于
Use a branchless sequence that is one byte shorter on 64-bit, same size on 32-bit. Thanks to Pete Cawley for suggesting this variant.
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- 12 8月, 2020 3 次提交
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由 Alexander Monakov 提交于
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由 Alexander Monakov 提交于
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由 Alexander Monakov 提交于
longjmp 'val' argument is an int, but the assembly is referencing 64-bit registers as if the argument was a long, or the caller was responsible for extending the argument. Though the psABI is not clear on this, the interpretation in GCC is that high bits may be arbitrary and the callee is responsible for sign/zero-extending the value as needed (likewise for return values: callers must anticipate that high bits may be garbage). Therefore testing %rax is a functional bug: setjmp would wrongly return zero if longjmp was called with val==0, but high bits of %rsi happened to be non-zero. Rewrite the prologue to refer to 32-bit registers. In passing, change 'test' to use %rsi, as there's no advantage to using %rax and the new form is cheaper on processors that do not perform move elimination.
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- 09 8月, 2020 1 次提交
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由 Rich Felker 提交于
a number of users performing seccomp filtering have requested use of the new individual syscall numbers for socket syscalls, rather than the legacy multiplexed socketcall, since the latter has the arguments all in memory where they can't participate in filter decisions. previously, some archs used the multiplexed socketcall if it was historically all that was available, while other archs used the separate syscalls. the intent was that the latter set only include archs that have "always" had separate socket syscalls, at least going back to linux 2.6.0. however, at least powerpc, powerpc64, and sh were wrongly included in this set, and thus socket operations completely failed on old kernels for these archs. with the changes made here, the separate syscalls are always preferred, but fallback code is compiled for archs that also define SYS_socketcall. two such archs, mips (plain o32) and microblaze, define SYS_socketcall despite never having needed it, so it's now undefined by their versions of syscall_arch.h to prevent inclusion of useless fallback code. some archs, where the separate syscalls were only added after the addition of SYS_accept4, lack SYS_accept. because socket calls are always made with zeros in the unused argument positions, it suffices to just use SYS_accept4 to provide a definition of SYS_accept, and this is done to make happy the macro machinery that concatenates the socket call name onto __SC_ and SYS_.
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- 06 8月, 2020 5 次提交
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由 Szabolcs Nagy 提交于
same approach as in sqrt. sqrtl was broken on aarch64, riscv64 and s390x targets because of missing quad precision support and on m68k-sf because of missing ld80 sqrtl. this implementation is written for quad precision and then edited to make it work for both m68k and x86 style ld80 formats too, but it is not expected to be optimal for them. note: using fp instructions for the initial estimate when such instructions are available (e.g. double prec sqrt or rsqrt) is avoided because of fenv correctness.
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由 Szabolcs Nagy 提交于
for targets where long double is different from double.
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由 Szabolcs Nagy 提交于
same method as in sqrt, this was tested on all inputs against an sqrtf instruction. (the only difference found was that x86 sqrtf does not signal the x86 specific input-denormal exception on negative subnormal inputs while the software sqrtf does, this is fine as it was designed for ieee754 exceptions only.) there is known faster method: "Computing Floating-Point Square Roots via Bivariate Polynomial Evaluation" that computes sqrtf directly via pipelined polynomial evaluation which allows more parallelism, but the design does not generalize easily to higher precisions.
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由 Szabolcs Nagy 提交于
approximate 1/sqrt(x) and sqrt(x) with goldschmidt iterations. this is known to be a fast method for computing sqrt, but it is tricky to get right, so added detailed comments. use a lookup table for the initial estimate, this adds 256bytes rodata but it can be shared between sqrt, sqrtf and sqrtl. this saves one iteration compared to a linear estimate. this is for soft float targets, but it supports fenv by using a floating-point operation to get the final result. the result is correctly rounded in all rounding modes. if fenv support is turned off then the nearest rounded result is computed and inexact exception is not signaled. assumes fast 32bit integer arithmetics and 32 to 64bit mul.
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由 Rich Felker 提交于
prior to this change, the canonical name came from the first hosts file line matching the requested family, so the canonical name for a given hostname could differ depending on whether it was requested with AF_UNSPEC or a particular family (AF_INET or AF_INET6). now, the canonical name is deterministically the first one to appear with the requested name as an alias.
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- 05 8月, 2020 1 次提交
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由 Rich Felker 提交于
the existing code clobbered the canonical name already discovered every time another matching line was found, which will necessarily be the case when a hostname has both IPv4 and v6 definitions. patch by Wolf.
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- 04 8月, 2020 1 次提交
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由 Rich Felker 提交于
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- 03 8月, 2020 1 次提交
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由 Rich Felker 提交于
this is actually a functional fix at present, since the C sqrtl does not support ld80 and just wraps double sqrt. once that's fixed it will just be an optimization.
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- 25 7月, 2020 1 次提交
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由 Bartosz Brachaczek 提交于
if len==0, an uninitalized variable would be returned
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- 07 7月, 2020 2 次提交
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由 Rich Felker 提交于
the previous commit addressing async-signal-safety issues around pthread_kill did not fully fix pthread_cancel, which is also required (albeit rather irrationally) to be async-cancel-safe. without blocking implementation-internal signals, it's possible that, when async cancellation is enabled, a cancel signal sent by another thread interrupts pthread_kill while the killlock for a targeted thread is held. as a result, the calling thread will terminate due to cancellation without ever unlocking the targeted thread's killlock, and thus the targeted thread will be unable to exit.
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由 Rich Felker 提交于
pthread_kill is required to be AS-safe. that requirement can't be met if the target thread's killlock can be taken in contexts where application-installed signal handlers can run. block signals around use of this lock in all pthread_* functions which target a tid, and reorder blocking/unblocking of signals in pthread_exit so that they're blocked whenever the killlock is held.
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- 06 7月, 2020 1 次提交
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由 Rich Felker 提交于
this broke mallocng size_to_class on archs without a native implementation of a_clz_32. the incorrect logic seems to have been something i derived from a related but distinct log2-type operation. with the change made here, it passes an exhaustive test. as this function is new and presently only used by mallocng, no other functionality was affected.
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- 02 7月, 2020 1 次提交
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由 Julien Ramseier 提交于
vfscanf() may use the variable 'alloc' uninitialized when taking the branch introduced by commit b287cd74. Spotted by clang.
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- 01 7月, 2020 2 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
the intent here is to keep oldmalloc as an option, at least for the short term, in case any users are negatively impacted in some way by mallocng and need to fallback until their issues are resolved.
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- 30 6月, 2020 2 次提交
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由 Rich Felker 提交于
the files added come from the mallocng development repo, commit 2ed58817cca5bc055974e5a0e43c280d106e696b. they comprise a new malloc implementation, developed over the past 9 months, to replace the old allocator (since dubbed "oldmalloc") with one that retains low code size and minimal baseline memory overhead while avoiding fundamental flaws in oldmalloc and making significant enhancements. these include highly controlled fragmentation, fine-grained ability to return memory to the system when freed, and strong hardening against dynamic memory usage errors by the caller. internally, mallocng derives most of these properties from tightly structuring memory, creating space for allocations as uniform-sized slots within individually mmapped (and individually freeable) allocation groups. smaller-than-pagesize groups are created within slots of larger ones. minimal group size is very small, and larger sizes (in geometric progression) only come into play when usage is high. all data necessary for maintaining consistency of the allocator state is tracked in out-of-band metadata, reachable via a validated path from minimal in-band metadata. all pointers passed (to free, etc.) are validated before any stores to memory take place. early reuse of freed slots is avoided via approximate LRU order of freed slots. further hardening against use-after-free and double-free, even in the case where the freed slot has been reused, is made by cycling the offset within the slot at which the allocation is placed; this is possible whenever the slot size is larger than the requested allocation.
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由 Rich Felker 提交于
this includes both an implementation of reclaimed-gap donation from ldso and a version of mallocng's glue.h with namespace-safe linkage to underlying syscalls, integration with AT_RANDOM initialization, and internal locking that's optimized out when the process is single-threaded.
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- 27 6月, 2020 1 次提交
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由 Rich Felker 提交于
these are based on the ARM optimized-routines repository v20.05 (ef907c7a799a), with macro dependencies flattened out and memmove code removed from memcpy. this change is somewhat unfortunate since having the branch for memmove support in the large n case of memcpy is the performance-optimal and size-optimal way to do both, but it makes memcpy alone (static-linked) about 40% larger and suggests a policy that use of memcpy as memmove is supported. tabs used for alignment have also been replaced with spaces.
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- 26 6月, 2020 1 次提交
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由 Andre McCurdy 提交于
Allow the existing ARM assembler memcpy implementation to be used for both big and little endian targets.
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- 21 6月, 2020 1 次提交
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由 Rich Felker 提交于
the child is single-threaded, but may still need to synchronize with last changes made to memory by another thread in the parent, so set need_locks to -1 whereby the next lock-taker will drop to 0 and prevent further barriers/locking.
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- 16 6月, 2020 3 次提交
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由 Rich Felker 提交于
otherwise, shrink in-place. as explained in the description of commit 3e16313f, the split here is valid without holding split_merge_lock because all chunks involved are in the in-use state.
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由 Rich Felker 提交于
commit 3e16313f introduced this bug by making the copy case reachable with n (new size) smaller than n0 (original size). this was left as the only way of shrinking an allocation because it reduces fragmentation if a free chunk of the appropriate size is available. when that's not the case, another approach may be better, but any such improvement would be independent of fixing this bug.
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由 Rich Felker 提交于
access always computes result with real ids not effective ones, so it is not a valid means of determining whether the directory is readable. instead, attempt to open it before reporting whether it's readable, and then use fdopendir rather than opendir to open and read the entries. effort is made here to keep fd_limit behavior the same as before even if it was not correct.
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- 11 6月, 2020 6 次提交
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由 Rich Felker 提交于
some archs already have a_clz_32, used to provide a_ctz_32, but it hasn't been mandatory because it's not used anywhere yet. mallocng will need it, however, so add it now. it should probably be optimized better, but doesn't seem to make a difference at present.
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由 Rich Felker 提交于
it both malloc and aligned_alloc have been replaced but the internal aligned_alloc still gets called, the replacement is a wrapper of some sort. it's not clear if this usage should be officially supported, but it's at least a plausibly interesting debugging usage, and easy to do. it should not be relied upon unless it's documented as supported at some later time.
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由 Rich Felker 提交于
this is in preparation for improving behavior of malloc interposition.
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由 Rich Felker 提交于
a new weak predicate function replacable by the malloc implementation, __malloc_allzerop, is introduced. by default it's always false; the default version will be used when static linking if the bump allocator was used (in which case performance doesn't matter) or if malloc was replaced by the application. only if the real internal malloc is linked (always the case with dynamic linking) does the real version get used. if malloc was replaced dynamically, as indicated by __malloc_replaced, the predicate function is ignored and conditional-memset is always performed.
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由 Rich Felker 提交于
it's not part of the malloc implementation but glue with musl dynamic linker.
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由 Rich Felker 提交于
abstractly, calloc is completely malloc-implementation-independent; it's malloc followed by memset, or as we do it, a "conditional memset" that avoids touching fresh zero pages. previously, calloc was kept separate for the bump allocator, which can always skip memset, and the version of calloc provided with the full malloc conditionally skipped the clearing for large direct-mmapped allocations. the latter is a moderately attractive optimization, and can be added back if needed. however, further consideration to make it correct under malloc replacement would be needed. commit b4b1e103 documented the contract for malloc replacement as allowing omission of calloc, and indeed that worked for dynamic linking, but for static linking it was possible to get the non-clearing definition from the bump allocator; if not for that, it would have been a link error trying to pull in malloc.o. the conditional-clearing code for the new common calloc is taken from mal0_clear in oldmalloc, but drops the need to access actual page size and just uses a fixed value of 4096. this avoids potentially needing access to global data for the sake of an optimization that at best marginally helps archs with offensively-large page sizes.
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- 04 6月, 2020 4 次提交
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由 Rich Felker 提交于
this sets the stage for replacement, and makes it practical to keep oldmalloc around as a build option for a while if that ends up being useful. only the files which are actually part of the implementation are moved. memalign and posix_memalign are entirely generic. in theory calloc could be pulled out too, but it's useful to have it tied to the implementation so as to optimize out unnecessary memset when implementation details make it possible to know the memory is already clear.
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由 Rich Felker 提交于
this function is no longer used elsewhere, and moving it reduces the number of source files specific to the malloc implementation.
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由 Rich Felker 提交于
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由 Rich Felker 提交于
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