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* rts/linker: Introduce a notion of strong symbolsBen Gamari2021-10-121-13/+22
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* rts/linker: Resolve __fini_array_* symbols to NULLGHC GitLab CI2021-10-121-0/+4
| | | | | If the __fini_array_{start,end} symbols are not defined (e.g. as is often the case when linking against musl) then resolve them to NULL.
* rts/linker: Define _DYNAMIC when necessaryBen Gamari2021-10-121-1/+13
| | | | | | Usually the dynamic linker would define _DYNAMIC. However, when dynamic linking is not supported (e.g. on musl) it is safe to define it to be NULL.
* rts/Linker: Fix __dso_handle handlingGHC GitLab CI2021-10-121-10/+27
| | | | | | | | | | | | Previously the linker's handling of __dso_handle was quite wrong. Not only did we claim that __dso_handle could be NULL when statically linking (which it can not), we didn't even implement this mislead theory faithfully and instead resolved the symbol to a random pointer. This lead to the failing relocations on AArch64 noted in #20493. Here we try to implement __dso_handle as a dynamic linker would do, choosing an address within the loaded object (specifically its start address) to serve as the object's handle.
* Make `PosixSource.h` installed and under `rts/`John Ericson2021-08-091-1/+1
| | | | | | is used outside of the rts so we do this rather than just fish it out of the repo in ad-hoc way, in order to make packages in this repo more self-contained.
* Allocate Adjustors and mark them readable in two stepsMoritz Angermann2021-03-291-1/+1
| | | | | | | | | This drops allocateExec for darwin, and replaces it with a alloc, write, mark executable strategy instead. This prevents us from trying to allocate an executable range and then write to it, which X^W will prohibit on darwin. This will *only* work if we can use mmap.
* linker: Fix atexit handlers on PETamar Christina2021-02-221-3/+0
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* rts/linker: Don't assume existence of dlinfoBen Gamari2021-01-171-1/+0
| | | | | | | | | The native-code codepath uses dlinfo to identify memory regions owned by a loaded dynamic object, facilitating safe unload. Unfortunately, this interface is not always available. Add an autoconf check for it and introduce a safe fallback behavior. Fixes #19159.
* rts/Linker: Add noreturn to loadNativeObj on non-ELF platformsBen Gamari2021-01-071-2/+6
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* rts/linker: Use m32 to allocate symbol extras in PEi386Ben Gamari2020-12-011-2/+3
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* rts/m32: Introduce NEEDS_M32 macroBen Gamari2020-12-011-4/+6
| | | | Instead of relying on RTS_LINKER_USE_MMAP
* rts/Linker: Introduce Windows implementations for mmapForLinker, et al.Ben Gamari2020-12-011-1/+32
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* rts/linker: Introduce munmapForLinkerBen Gamari2020-12-011-4/+14
| | | | Consolidates munmap calls to ensure consistent error handling.
* rts: Introduce mmapAnonForLinkerBen Gamari2020-12-011-1/+11
| | | | | | | | Previously most of the uses of mmapForLinker were mapping anonymous memory, resulting in a great deal of unnecessary repetition. Factor this out into a new helper. Also fixes a few places where error checking was missing or suboptimal.
* rts/linker: Move shared library loading logic into Elf.cBen Gamari2020-11-301-140/+2
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* rts/linker: Initialise CCSs from native shared objectsBen Gamari2020-11-301-0/+6
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* rts/linker: Don't allow shared libraries to be loaded multiple timesBen Gamari2020-11-301-0/+9
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* rts/linker: Replace some ASSERTs with CHECKBen Gamari2020-11-301-5/+3
| | | | | | | | In the past some people have confused ASSERT, which is for checking internal invariants, which CHECK, which should be used when checking things that might fail due to bad input (and therefore should be enabled even in the release compiler). Change some of these cases in the linker to use CHECK.
* Add loadNativeObj and unloadNativeObjRay Shih2020-11-111-2/+194
| | | | | | | | | | | | | | | | | | | (This change is originally written by niteria) This adds two functions: * `loadNativeObj` * `unloadNativeObj` and implements them for Linux. They are useful if you want to load a shared object with Haskell code using the system linker and have GHC call dlclose() after the code is no longer referenced from the heap. Using the system linker allows you to load the shared object above outside the low-mem region. It also loads the DWARF sections in a way that `perf` understands. `dl_iterate_phdr` is what makes this implementation Linux specific.
* Fix and enable object unloading in GHCiÖmer Sinan Ağacan2020-11-111-79/+61
| | | | | | | Fixes #16525 by tracking dependencies between object file symbols and marking symbol liveness during garbage collection See Note [Object unloading] in CheckUnload.c for details.
* [AArch64] Aarch64 Always PICMoritz Angermann2020-11-061-38/+2
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* rts: Refactor unloading of foreign export StablePtrsBen Gamari2020-09-181-7/+11
| | | | | | Previously we would allocate a linked list cell for each foreign export. Now we can avoid this by taking advantage of the fact that they are already broken into groups.
* rts: Refactor foreign export trackingBen Gamari2020-09-181-33/+4
| | | | | | | | | This avoids calling `libc` in the initializers which are responsible for registering foreign exports. We believe this should avoid the corruption observed in #18548. See Note [Tracking foreign exports] in rts/ForeignExports.c for an overview of the new scheme.
* [linker] Fix out of range relocations.Moritz Angermann2020-07-231-8/+77
| | | | | | | | | | | | mmap may return address all over the place. mmap_next will ensure we get the next free page after the requested address. This is especially important for linking on aarch64, where the memory model with PIC admits relocations in the +-4GB range, and as such we can't work with arbitrary object locations in memory. Of note: we map the rts into process space, so any mapped objects must not be ouside of the 4GB from the processes address space.
* winio: Small linker comment and ifdef cleanupsTamar Christina2020-07-151-5/+3
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* rts linker: teach the linker about GLIBC's special handling of *stat, mknod ↵Adam Sandberg Ericsson2020-07-071-3/+31
| | | | and atexit functions #7072
* fix windows bootstrap due to linker changesTamar Christina2020-06-181-14/+8
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* Fix uninitialized field read in Linker.cÖmer Sinan Ağacan2020-06-181-20/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Valgrind report of the bug when running the test `linker_unload`: ==29666== Conditional jump or move depends on uninitialised value(s) ==29666== at 0x369C5B4: setOcInitialStatus (Linker.c:1305) ==29666== by 0x369C6C5: mkOc (Linker.c:1347) ==29666== by 0x36C027A: loadArchive_ (LoadArchive.c:522) ==29666== by 0x36C0600: loadArchive (LoadArchive.c:626) ==29666== by 0x2C144CD: ??? (in /home/omer/haskell/ghc_2/testsuite/tests/rts/linker/linker_unload.run/linker_unload) ==29666== ==29666== Conditional jump or move depends on uninitialised value(s) ==29666== at 0x369C5B4: setOcInitialStatus (Linker.c:1305) ==29666== by 0x369C6C5: mkOc (Linker.c:1347) ==29666== by 0x369C9F6: preloadObjectFile (Linker.c:1507) ==29666== by 0x369CA8D: loadObj_ (Linker.c:1536) ==29666== by 0x369CB17: loadObj (Linker.c:1557) ==29666== by 0x3866BC: main (linker_unload.c:33) The problem is `mkOc` allocates a new `ObjectCode` and calls `setOcInitialStatus` without initializing the `status` field. `setOcInitialStatus` reads the field as first thing: static void setOcInitialStatus(ObjectCode* oc) { if (oc->status == OBJECT_DONT_RESOLVE) return; if (oc->archiveMemberName == NULL) { oc->status = OBJECT_NEEDED; } else { oc->status = OBJECT_LOADED; } } `setOcInitialStatus` is unsed in two places for two different purposes: in `mkOc` where we don't have the `status` field initialized yet (`mkOc` is supposed to initialize it), and `loadOc` where we do have `status` field initialized and we want to update it. Instead of splitting the function into two functions which are both called just once I inline the functions in the use sites and remove it. Fixes #18342
* [linker] Adds void printLoadedObjects(void);wip/angerman/print-loaded-objectsMoritz Angermann2020-06-041-2/+28
| | | | | | This allows us to dump in-memory object code locations for debugging. Fixup printLoadedObjects prototype
* Linker.c: initialize n_symbols of ObjectCode with other fieldsÖmer Sinan Ağacan2020-05-081-0/+1
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* Fix typos, via a Levenshtein-style correctorBrian Wignall2020-01-041-1/+1
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* rts: Specialize hashing at call site rather than in struct.Crazycolorz52019-12-111-6/+6
| | | | | | | | | | | | | | | | Separate word and string hash tables on the type level, and do not store the hashing function. Thus when a different hash function is desire it is provided upon accessing the table. This is worst case the same as before the change, and in the majority of cases is better. Also mark the functions for aggressive inlining to improve performance. {F1686506} Reviewers: bgamari, erikd, simonmar Subscribers: rwbarton, thomie, carter GHC Trac Issues: #13165 Differential Revision: https://phabricator.haskell.org/D4889
* rts/linker: Ensure that code isn't writableBen Gamari2019-11-041-7/+54
| | | | | | | | | | | | | | | | | | | | | | | | | | For many years the linker would simply map all of its memory with PROT_READ|PROT_WRITE|PROT_EXEC. However operating systems have been becoming increasingly reluctant to accept this practice (e.g. #17353 and #12657) and for good reason: writable code is ripe for exploitation. Consequently mmapForLinker now maps its memory with PROT_READ|PROT_WRITE. After the linker has finished filling/relocating the mapping it must then call mmapForLinkerMarkExecutable on the sections of the mapping which contain executable code. Moreover, to make all of this possible it was necessary to redesign the m32 allocator. First, we gave (in an earlier commit) each ObjectCode its own m32_allocator. This was necessary since code loading and symbol resolution/relocation are currently interleaved, meaning that it is not possible to enforce W^X when symbols from different objects reside in the same page. We then redesigned the m32 allocator to take advantage of the fact that all of the pages allocated with the allocator die at the same time (namely, when the owning ObjectCode is unloaded). This makes a number of things simpler (e.g. no more page reference counting; the interface provided by the allocator for freeing is simpler). See Note [M32 Allocator] for details.
* rts: Make m32 allocator per-ObjectCodeBen Gamari2019-11-011-3/+7
| | | | | | | | | | | | | | | | | MacOS Catalina is finally going to force our hand in forbidden writable exeutable mappings. Unfortunately, this is quite incompatible with the current global m32 allocator, which mixes symbols from various objects in a single page. The problem here is that some of these symbols may not yet be resolved (e.g. had relocations performed) as this happens lazily (and therefore we can't yet make the section read-only and therefore executable). The easiest way around this is to simply create one m32 allocator per ObjectCode. This may slightly increase fragmentation for short-running programs but I suspect will actually improve fragmentation for programs doing lots of loading/unloading since we can always free all of the pages allocated to an object when it is unloaded (although this ability will only be implemented in a later patch).
* mmap: Factor out protection flagsBen Gamari2019-11-011-4/+3
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* Add new debug flag -DZTobias Guggenmos2019-10-031-2/+2
| | | | Zeros heap memory after gc freed it.
* rts: Rename the nondescript initProfiling2 to refreshProfilingCCSsDaniel Gröber2019-07-161-3/+2
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* Fix #16525: ObjectCode freed wrongly because of lack of info header checkPhuong Trinh2019-06-131-0/+6
| | | | | | | `checkUnload` currently doesn't check the info header of static objects. Thus, it may free an `ObjectCode` struct wrongly even if there's still a live static object whose info header lies in a mapped section of that `ObjectCode`. This fixes the issue by adding an appropriate check.
* rts/linker: Mmap into low memory on AArch64Ben Gamari2019-06-111-13/+22
| | | | | This extends mmapForLinker to use the same low-memory mapping strategy used on x86_64 on AArch64. See #16784.
* Address some todos and fixmesArtem Pyanykh2019-03-201-0/+1
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* Use segments for section layoutArtem Pyanykh2019-03-201-0/+50
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* Adjust section placement and relocation logic for Mach-OArtem Pyanykh2019-03-201-3/+7
| | | | | | | | | | | | | | 1. Place each section on a separate page to ensure required alignment (wastes lots ot space, needs to be improved). 2. Unwire relocation logic from macho sections (the most fiddly part is adjusting internal relocations). Other todos: 0. Add a test for section alignment. 1. Investigate 32bit relocations! 2. Fix memory leak in ZEROPAGE section allocation. 3. Fix creating redundant jump islands for GOT. 4. Investigate more compact section placement.
* Update Trac ticket URLs to point to GitLabRyan Scott2019-03-151-2/+2
| | | | | This moves all URL references to Trac tickets to their corresponding GitLab counterparts.
* Drop support for i386 and PowerPC in MachO linkerArtem Pyanykh2019-02-221-3/+1
| | | | | | Some code is broken, there are no CI targets (so not obvious how to test), and no one seems to have built GHC for any of the above platforms in years.
* Allocate bss section within proper range of other sectionsZejun Wu2019-01-301-10/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: This re-applies {D5195} and {D5235}, they were reverted as part of diff stack to unbreak i386. The proper fix is done in {D5289}. Allocate bss section within proper range of other sections: * when `+RTS -xp` is passed, allocate it contiguously as we did for jump islands * when we mmap the code to lower 2Gb, we should allocate bss section there too Test Plan: 1. `./validate` 2. with ``` DYNAMIC_GHC_PROGRAMS = NO DYNAMIC_BY_DEFAULT = NO ``` `TEST="T15729" make test` passed in both linux (both i386 and x86_64) and macos. 3. Also test in a use case where we used to encouter error like: ``` ghc-iserv-prof: R_X86_64_PC32 relocation out of range: (noname) = b90282ba ``` and now, everything works fine. Reviewers: simonmar, bgamari, angerman, erikd Reviewed By: simonmar Subscribers: rwbarton, carter GHC Trac Issues: #15729 Differential Revision: https://phabricator.haskell.org/D5290
* Add a RTS option -xp to load PIC object anywhere in address spaceZejun Wu2019-01-301-41/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: This re-applies {D5195} with fixes for i386: * Fix unused label warnings, see {D5230} or {D5273} * Fix a silly bug introduced by moving `#if` {P190} Add a RTS option -xp to load PIC object anywhere in address space. We do this by relaxing the requirement of <0x80000000 result of `mmapForLinker` and implying USE_CONTIGUOUS_MMAP. We also need to change calls to `ocInit` and `ocGetNames` to avoid dangling pointers when the address of `oc->image` is changed by `ocAllocateSymbolExtra`. Test Plan: See {D5195}, also test under i386: ``` $ uname -a Linux watashi-arch32 4.18.5-arch1-1.0-ARCH #1 SMP PREEMPT Tue Aug 28 20:45:30 CEST 2018 i686 GNU/Linux $ cd testsuite/tests/th/ && make test ... ``` will run `./validate` on stacked diff. Reviewers: simonmar, bgamari, alpmestan, trommler, hvr, erikd Reviewed By: simonmar Subscribers: rwbarton, carter Differential Revision: https://phabricator.haskell.org/D5289
* Revert "Batch merge"Ben Gamari2019-01-301-47/+43
| | | | This reverts commit 76c8fd674435a652c75a96c85abbf26f1f221876.
* Batch mergeBen Gamari2019-01-301-43/+47
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* Extend linker-script workaround to work with musl libcSamuel Holland2019-01-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | GHC has code to handle unsuffixed .so files that are linker scripts pointing to the real shared library. The detection is done by parsing the result of `dlerror()` after calling `dlopen()` and looking for certain error strings. On musl libc, the error message is "Exec format error", which happens to be `strerror(ENOEXEC)`: ``` $ cat tmp.c #include <dlfcn.h> #include <stdio.h> int main(void) { dlopen("libz.so", RTLD_NOW | RTLD_GLOBAL); puts(dlerror()); return 0; } $ gcc -o tmp tmp.c $ ./tmp Error loading shared library libz.so: Exec format error $ ``` This change fixes the workaround to also work on musl libc. Link: https://phabricator.haskell.org/D5474
* linker: store entire link map and use it.Tamar Christina2018-12-041-10/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: This fixes a corner case in which we have seen the symbol multiple times in different static libraries, but due to a depencency we end up loading the symbol from a library other than the first one. Previously the runtime linker would only track symbols from the first library and did not store the full link map. In this case it was unable to find the address for the symbols in the second library during delay loading. This change stores the address of all symbols seen so a full link map is generated, such that when we make a different decision later than what was expected we're able to still correctly load the library. Test Plan: ./validate, new testcase T15894 Reviewers: angerman, bgamari, erikd, simonmar Reviewed By: bgamari Subscribers: rwbarton, carter GHC Trac Issues: #15894 Differential Revision: https://phabricator.haskell.org/D5353
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