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path: root/arch/x86_64/reloc.h
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2015-04-13dynamic linker bootstrap overhaulRich Felker-30/+13
this overhaul further reduces the amount of arch-specific code needed by the dynamic linker and removes a number of assumptions, including: - that symbolic function references inside libc are bound at link time via the linker option -Bsymbolic-functions. - that libc functions used by the dynamic linker do not require access to data symbols. - that static/internal function calls and data accesses can be made without performing any relocations, or that arch-specific startup code handled any such relocations needed. removing these assumptions paves the way for allowing libc.so itself to be built with stack protector (among other things), and is achieved by a three-stage bootstrap process: 1. relative relocations are processed with a flat function. 2. symbolic relocations are processed with no external calls/data. 3. main program and dependency libs are processed with a fully-functional libc/ldso. reduction in arch-specific code is achived through the following: - crt_arch.h, used for generating crt1.o, now provides the entry point for the dynamic linker too. - asm is no longer responsible for skipping the beginning of argv[] when ldso is invoked as a command. - the functionality previously provided by __reloc_self for heavily GOT-dependent RISC archs is now the arch-agnostic stage-1. - arch-specific relocation type codes are mapped directly as macros rather than via an inline translation function/switch statement.
2014-06-19add tlsdesc support for x86_64Rich Felker-0/+2
2014-06-18refactor to remove arch-specific relocation code from dynamic linkerRich Felker-29/+12
this was one of the main instances of ugly code duplication: all archs use basically the same types of relocations, but roughly equivalent logic was duplicated for each arch to account for the different naming and numbering of relocation types and variation in whether REL or RELA records are used. as an added bonus, both REL and RELA are now supported on all archs, regardless of which is used by the standard toolchain.
2014-06-16dynamic linker: permit error returns from arch-specific reloc functionRich Felker-1/+2
the immediate motivation is supporting TLSDESC relocations which require allocation and thus may fail (unless we pre-allocate), but this mechanism should also be used for throwing an error on unsupported or invalid relocation types, and perhaps in certain cases, for reporting when a relocation is not satisfiable.
2013-07-18make the dynamic linker find its path file relative to its own locationRich Felker-1/+1
prior to this change, using a non-default syslibdir was impractical on systems where the ordinary library paths contain musl-incompatible library files. the file containing search paths was always taken from /etc, which would either correspond to a system-wide musl installation, or fail to exist at all, resulting in searching of the default library path. the new search strategy is safe even for suid programs because the pathname used comes from the PT_INTERP header of the program being run, rather than any external input. as part of this change, I have also begun differentiating the names of arch variants that differ by endianness or floating point calling convention. the corresponding changes in the build system and and gcc wrapper script (to use an alternate dynamic linker name) for these configurations have not yet been made.
2012-10-05fix incorrect TLS reloc macro names in x86_64 reloc.hRich Felker-3/+3
2012-10-04dynamic-linked TLS support for everything but dlopen'd libsRich Felker-1/+16
currently, only i386 is tested. x86_64 and arm should probably work. the necessary relocation types for mips and microblaze have not been added because I don't understand how they're supposed to work, and I'm not even sure if it's defined yet on microblaze. I may be able to reverse engineer the requirements out of gcc/binutils output.
2011-06-25fix some symbol resolution issues in dynamic linkerRich Felker-0/+1
1. search was wrongly beginning with lib itself rather than dso head 2. inconsistent resolution of function pointers for functions in plt
2011-06-25proper path searching for dynamic linkerRich Felker-0/+2
first, use $LD_LIBRARY_PATH unless suid. if that fails, read path from /etc/ld-musl-$ARCH.path and fallback to a builtin default.
2011-06-18experimental dynamic linker!Rich Felker-0/+28
some notes: - library search path is hard coded - x86_64 code is untested and may not work - dlopen/dlsym is not yet implemented - relocations in read-only memory won't work