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2015-04-22optimize spin lock not to dirty cache line while spinningRich Felker-1/+1
2015-04-22in visibility preinclude, remove overrides for stdin/stdout/stderrRich Felker-3/+0
the motivation for this change is that the extra declaration (with or without visibility) using "struct _IO_FILE" instead of "FILE" seems to trigger a bug in gcc 3.x where it considers the types mismatched. however, this change also results in slightly better code and it is valid because (1) these three objects are constant, and (2) applying the & operator to any of them is invalid C, since they are not even specified to be objects. thus it does not matter if the application and libc see different addresses for them, as long as the (initial, unchanging) value is seen the same by both.
2015-04-22fix inconsistent visibility for __hwcap and __sysinfo symbolsRich Felker-5/+3
these are used as hidden by asm files (and such use is the whole reason they exist), but their actual definitions were not hidden.
2015-04-22remove additional libc struct accessor cruftRich Felker-12/+0
commit f9cccfc16e58b39ee381fbdfb8688db3bb8e3555 left behind the part in libc.c; remove it too.
2015-04-22remove useless visibility application from static-linking-only codeRich Felker-3/+2
part of the goal here is to eliminate use of the ATTR_LIBC_VISIBILITY macro outside of libc.h, since it was never intended to be 'public'.
2015-04-22remove libc.h dependency from otherwise-independent multibyte codeRich Felker-2/+4
2015-04-22remove cruft for libc struct accessor function and broken visibilityRich Felker-18/+0
these were hacks to work around toolchains that could not properly optimize PIC accesses based on visibility and would generate GOT lookups even for hidden data, which broke the old dynamic linker. since commit f3ddd173806fd5c60b3f034528ca24542aecc5b9 it no longer matters; the dynamic linker does not assume accessibility of this data until stage 3.
2015-04-22make configure check for visibility preinclude compatible with pccRich Felker-3/+3
pcc does not search for -include relative to the working directory unless -I. is used. rather than adding -I., which could be problematic if there's extra junk in the top-level directory, switch back to the old method (reverting commit 60ed988fd6c67b489d7cc186ecaa9db4e5c25b8c) of using -include vis.h and relying on -I./src/internal being present on the command line (which the Makefile guarantees). to fix the breakage that was present in trycppif checks with the old method, $CFLAGS_AUTO is removed from the command line passed to trycppif; this is valid since $CFLAGS_AUTO should not contain options that alter compiler semantics or ABI, only optimizations, warnings, etc.
2015-04-21fix duplocale clobbering of new locale struct with memcpy of oldRich Felker-1/+2
when the non-stub duplocale code was added as part of the locale framework in commit 0bc03091bb674ebb9fa6fe69e4aec1da3ac484f2, the old code to memcpy the old locale object to the new one was left behind. the conditional for the memcpy no longer makes sense, because the conditions are now always-true when it's reached, and the memcpy is wrong because it clobbers the new->messages_name pointer setup just above. since the messages_name and ctype_utf8 members have already been copied, all that remains is the cat[] array. these pointers are volatile, so using memcpy to copy them is formally wrong; use a for loop instead.
2015-04-21configure: check for -march and -mtune passed via CCAndre McCurdy-2/+4
Some build environments pass -march and -mtune as part of CC, therefore update configure to check both CC and CFLAGS before making the decision to fall back to generic -march and -mtune options for x86. Signed-off-by: Andre McCurdy <armccurdy@gmail.com>
2015-04-21remove dead case for F_SETLKW in fcntlRich Felker-1/+0
the first switch already returns in the F_SETLKW code path so it need not be handled in the second switch. moreover the code in the second switch is wrong for the F_SETLKW command: it's not cancellable.
2015-04-21fix mmap leak in sem_open failure path for link callRich Felker-0/+1
the leak was found by static analysis (reported by Alexander Monakov), not tested/observed, but seems to have occured both when failing due to O_EXCL, and in a race condition with O_CREAT but not O_EXCL where a semaphore by the same name was created concurrently.
2015-04-21remove always-true conditional in dynamic linker TLSDESC processingRich Felker-1/+1
the allocating path which can fail is for dynamic TLS, which can only occur at runtime, and the check for runtime was already made in the outer conditional.
2015-04-21remove redundant code in do_dlsym functionRich Felker-1/+1
commit 637dd2d383cc1f63bf02a732f03786857b22c7bd introduced the checks for RTLD_DEFAULT and RTLD_NEXT here, claiming they fixed a regression, but the above conditional block clearly already covered these cases, and removing the checks produces no difference in the generated code.
2015-04-20fix breakage in x32 dynamic linker due to mismatching register sizeRich Felker-1/+1
the jmp instruction requires a 64-bit register, so cast the desired PC address up to uint64_t, going through uintptr_t to ensure that it's zero-extended rather than possibly sign-extended.
2015-04-20fix regression in configure script with new visibility optionRich Felker-3/+3
commit de2b67f8d41e08caa56bf6540277f6561edb647f introduced a regression by adding a -include option to CFLAGS_AUTO which did not work without additional -I options. this broke subsequent trycppif tests and caused x86_64 to be misdetected as x32, among other issues. simply using the full relative pathname to vis.h rather than -I is the cleanest way to fix the problem.
2015-04-19add optional global visibility overrideRich Felker-1/+72
this is implemented via the build system and does not affect source files. the idea is to use protected or hidden visibility to prevent the compiler from pessimizing function calls within a shared (or position-independent static) libc in the form of overhead setting up for a call through the PLT. the ld-time symbol binding via the -Bsymbolic-functions option already optimized out the PLT itself, but not the code in the caller needed to support a call through the PLT. on some archs this overhead can be substantial; on others it's trivial.
2015-04-19remove invalid PLT calls from or1k asmRich Felker-3/+7
analogous to commit 646cb9a4a04e5ed78e2dd928bf9dc6e79202f609 for sh.
2015-04-19remove possible-textrels from powerpc asmRich Felker-2/+6
these are perfectly fine with ld-time symbol binding, but otherwise result in textrels. they cannot be replaced with @PLT jump targets because the PLT thunks require a GOT register to be setup, so use a hidden alias instead.
2015-04-19remove invalid PLT calls from microblaze asmRich Felker-2/+6
analogous to commit 646cb9a4a04e5ed78e2dd928bf9dc6e79202f609 for sh.
2015-04-19remove invalid PLT calls from sh asmRich Felker-2/+6
these are perfectly fine with ld-time symbol binding, but if the calls go through a PLT thunk, they are invalid because the caller does not setup a GOT register. use a hidden alias to bypass the issue.
2015-04-18remove potentially PIC-incompatible relocations from x86_64 and x32 asmRich Felker-7/+11
analogous to commit 8ed66ecbcba1dd0f899f22b534aac92a282f42d5 for i386.
2015-04-18remove the last of possible-textrels from i386 asmRich Felker-4/+16
none of these are actual textrels because of ld-time binding performed by -Bsymbolic-functions, but I'm changing them with the goal of making ld-time binding purely an optimization rather than relying on it for semantic purposes. in the case of memmove's call to memcpy, making it explicit that the memmove asm is assuming the forward-copying behavior of the memcpy asm is desirable anyway; in case memcpy is ever changed, the semantic mismatch would be apparent while editing memmcpy.s.
2015-04-18make dlerror state and message thread-local and dynamically-allocatedRich Felker-32/+65
this fixes truncation of error messages containing long pathnames or symbol names. the dlerror state was previously required by POSIX to be global. the resolution of bug 97 relaxed the requirements to allow thread-safe implementations of dlerror with thread-local state and message buffer.
2015-04-18add missing 'void' in prototypes of internal pthread functionsAlexander Monakov-6/+6
2015-04-18math: fix pow(+-0,-inf) not to raise divbyzero flagSzabolcs Nagy-3/+3
this reverts the commit f29fea00b5bc72d4b8abccba2bb1e312684d1fce which was based on a bug in C99 and POSIX and did not match IEEE-754 http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1515.pdf
2015-04-17apply hidden visibility to tlsdesc accessor functionsRich Felker-0/+10
these functions are never called directly; only their addresses are used, so PLT indirections should never happen unless a broken application tries to redefine them, but it's still best to make them hidden.
2015-04-17comment fixes in aarch64 tlsdesc asmSzabolcs Nagy-4/+4
2015-04-17ensure debugger hook for dynamic linker does not point to a PLT slotRich Felker-2/+4
this change is made in preparation to support linking without -Bsymbolic-functions.
2015-04-17add PR_*_FP_MODE prctl optionsSzabolcs Nagy-0/+5
new in linux v4.0, commit 9791554b45a2acc28247f66a5fd5bbc212a6b8c8 used to work around a floating-point abi issue on mips
2015-04-17add PR_MPX_*_MANAGEMENT prctl optionsSzabolcs Nagy-0/+3
new in linux v3.19, commit fe3d197f84319d3bce379a9c0dc17b1f48ad358c used for on-demand kernel allocation of bounds tables for mpx on x86
2015-04-17add IP_CHECKSUM socket option to netinet/in.hSzabolcs Nagy-0/+1
new in linux v4.0, commit ad6f939ab193750cc94a265f58e007fb598c97b7
2015-04-17add execveat syscall number to microblazeSzabolcs Nagy-0/+2
syscall number was reserved in linux v4.0, kernel commit add4b1b02da7e7ec35c34dd04d351ac53f3f0dd8
2015-04-17improve ctype.h macros to diagnose errorsRich Felker-6/+6
the casts of the argument to unsigned int suppressed diagnosis of errors like passing a pointer instead of a character. putting the actual function call in an unreachable branch restores any diagnostics that would be present if the macros didn't exist and functions were used.
2015-04-17fix missing quotation mark in mips crt_arch.h that broke buildRich Felker-1/+1
2015-04-17fix mips fesetenv(FE_DFL_ENV) againRich Felker-0/+1
commit 5fc1487832e16aa2119e735a388d5f36c8c139e2 attempted to fix it, but neglected the fact that mips has branch delay slots.
2015-04-17fix PLT call offset in sh dlsym asmRich Felker-3/+3
the braf instruction's destination register is an offset from the address of the braf instruction plus 4 (or equivalently, the address of the next instruction after the delay slot). the code for dlsym was incorrectly computing the offset to pass using the address of the delay slot itself. in other places, a label was placed after the delay slot, but I find this confusing. putting the label on the branch instruction itself, and manually adding 4, makes it more clear which branch the offset in the constant pool goes with.
2015-04-17fix sh build regressions in asmRich Felker-2/+2
even hidden functions need @PLT symbol references; otherwise an absolute address is produced instead of a PC-relative one.
2015-04-17fix sh __set_thread_area uninitialized return valueRich Felker-1/+2
this caused the dynamic linker/startup code to abort when r0 happened to contain a negative value.
2015-04-17redesign sigsetjmp so that signal mask is restored after longjmpRich Felker-133/+177
the conventional way to implement sigsetjmp is to save the signal mask then tail-call to setjmp; siglongjmp then restores the signal mask and calls longjmp. the problem with this approach is that a signal already pending, or arriving between unmasking of signals and restoration of the saved stack pointer, will have its signal handler run on the stack that was active before siglongjmp was called. this can lead to unbounded stack usage when siglongjmp is used to leave a signal handler. in the new design, sigsetjmp saves its own return address inside the extended part of the sigjmp_buf (outside the __jmp_buf part used by setjmp) then calls setjmp to save a jmp_buf inside its own execution. it then tail-calls to __sigsetjmp_tail, which uses the return value of setjmp to determine whether to save the current signal mask or restore a previously-saved mask. as an added bonus, this design makes it so that siglongjmp and longjmp are identical. this is useful because the __longjmp_chk function we need to add for ABI-compatibility assumes siglongjmp and longjmp are the same, but for different reasons -- it was designed assuming either can access a flag just past the __jmp_buf indicating whether the signal masked was saved, and act on that flag. however, early versions of musl did not have space past the __jmp_buf for the non-sigjmp_buf version of jmp_buf, so our setjmp cannot store such a flag without risking clobbering memory on (very) old binaries.
2015-04-14use hidden __tls_get_new for tls/tlsdesc lookup fallback casesRich Felker-5/+13
previously, the dynamic tlsdesc lookup functions and the i386 special-ABI ___tls_get_addr (3 underscores) function called __tls_get_addr when the slot they wanted was not already setup; __tls_get_addr would then in turn also see that it's not setup and call __tls_get_new. calling __tls_get_new directly is both more efficient and avoids the issue of calling a non-hidden (public API/ABI) function from asm. for the special i386 function, a weak reference to __tls_get_new is used since this function is not defined when static linking (the code path that needs it is unreachable in static-linked programs).
2015-04-14cleanup use of visibility attributes in pthread_cancel.cRich Felker-8/+9
applying the attribute to a weak_alias macro was a hack. instead use a separate declaration to apply the visibility, and consolidate declarations together to avoid having visibility mess all over the file.
2015-04-14fix inconsistent visibility for internal syscall symbolsRich Felker-1/+16
2015-04-14use hidden visibility for call from dlsym to internal __dlsymRich Felker-3/+14
2015-04-14consistently use hidden visibility for cancellable syscall internalsRich Felker-30/+103
in a few places, non-hidden symbols were referenced from asm in ways that assumed ld-time binding. while these is no semantic reason these symbols need to be hidden, fixing the references without making them hidden was going to be ugly, and hidden reduces some bloat anyway. in the asm files, .global/.hidden directives have been moved to the top to unclutter the actual code.
2015-04-14fix inconsistent visibility for internal __tls_get_new functionRich Felker-3/+3
at the point of call it was declared hidden, but the definition was not hidden. for some toolchains this inconsistency produced textrels without ld-time binding.
2015-04-14use hidden visibility for i386 asm-internal __vsyscall symbolRich Felker-7/+9
otherwise the call instruction in the inline syscall asm results in textrels without ld-time binding.
2015-04-14make _dlstart_c function use hidden visibilityRich Felker-0/+1
otherwise the call/jump from the crt_arch.h asm may not resolve correctly without -Bsymbolic-functions.
2015-04-13remove initializers for decoded aux/dyn arrays in dynamic linkerRich Felker-5/+5
the zero initialization is redundant since decode_vec does its own clearing, and it increases the risk that buggy compilers will generate calls to memset. as long as symbols are bound at ld time, such a call will not break anything, but it may be desirable to turn off ld-time binding in the future.
2015-04-13allow libc itself to be built with stack protector enabledRich Felker-1/+26
this was already essentially possible as a result of the previous commits changing the dynamic linker/thread pointer bootstrap process. this commit mainly adds build system infrastructure: configure no longer attempts to disable stack protector. instead it simply determines how so the makefile can disable stack protector for a few translation units used during early startup. stack protector is also disabled for memcpy and memset since compilers (incorrectly) generate calls to them on some archs to implement struct initialization and assignment, and such calls may creep into early initialization. no explicit attempt to enable stack protector is made by configure at this time; any stack protector option supported by the compiler can be passed to configure in CFLAGS, and if the compiler uses stack protector by default, this default is respected.