mirror of git://sourceware.org/git/glibc.git
fddbd7c0ef
setcontext returns to the specified context via an indirect jump, so there should be a BTI j. In case of getcontext (and all other returns_twice functions) the compiler adds BTI j at the call site, but swapcontext is a normal c call that is currently not handled specially by the compiler. So we change swapcontext such that the saved context returns to a local address that has BTI j and then swapcontext returns to the caller via a normal RET. For this we save the original return address in the slot for x1 of the context because x1 need not be preserved by swapcontext but it is restored when the context saved by swapcontext is resumed. The alternative fix (which is done on x86) would make swapcontext special in the compiler so BTI j is emitted at call sites, on x86 there is an indirect_return attribute for this, on AArch64 we would have to use returns_twice. It was decided against because such fix may need user code updates: the attribute has to be added when swapcontext is called via a function pointer and it breaks always_inline functions with swapcontext. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> |
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| assert | ||
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| conform | ||
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| debug | ||
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| hesiod | ||
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| iconv | ||
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| include | ||
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| libio | ||
| locale | ||
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| login | ||
| mach | ||
| malloc | ||
| manual | ||
| math | ||
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| misc | ||
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| shadow | ||
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| stdio-common | ||
| stdlib | ||
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| support | ||
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| COPYING | ||
| COPYING.LIB | ||
| INSTALL | ||
| LICENSES | ||
| MAINTAINERS | ||
| Makeconfig | ||
| Makefile | ||
| Makefile.help | ||
| Makefile.in | ||
| Makerules | ||
| NEWS | ||
| README | ||
| Rules | ||
| abi-tags | ||
| aclocal.m4 | ||
| config.h.in | ||
| config.make.in | ||
| configure | ||
| configure.ac | ||
| extra-lib.mk | ||
| gen-locales.mk | ||
| libc-abis | ||
| libof-iterator.mk | ||
| o-iterator.mk | ||
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| test-skeleton.c | ||
| version.h | ||
README
This directory contains the sources of the GNU C Library. See the file "version.h" for what release version you have. The GNU C Library is the standard system C library for all GNU systems, and is an important part of what makes up a GNU system. It provides the system API for all programs written in C and C-compatible languages such as C++ and Objective C; the runtime facilities of other programming languages use the C library to access the underlying operating system. In GNU/Linux systems, the C library works with the Linux kernel to implement the operating system behavior seen by user applications. In GNU/Hurd systems, it works with a microkernel and Hurd servers. The GNU C Library implements much of the POSIX.1 functionality in the GNU/Hurd system, using configurations i[4567]86-*-gnu. When working with Linux kernels, this version of the GNU C Library requires Linux kernel version 3.2 or later. Also note that the shared version of the libgcc_s library must be installed for the pthread library to work correctly. The GNU C Library supports these configurations for using Linux kernels: aarch64*-*-linux-gnu alpha*-*-linux-gnu arm-*-linux-gnueabi csky-*-linux-gnuabiv2 hppa-*-linux-gnu i[4567]86-*-linux-gnu x86_64-*-linux-gnu Can build either x86_64 or x32 ia64-*-linux-gnu m68k-*-linux-gnu microblaze*-*-linux-gnu mips-*-linux-gnu mips64-*-linux-gnu powerpc-*-linux-gnu Hardware or software floating point, BE only. powerpc64*-*-linux-gnu Big-endian and little-endian. s390-*-linux-gnu s390x-*-linux-gnu riscv64-*-linux-gnu sh[34]-*-linux-gnu sparc*-*-linux-gnu sparc64*-*-linux-gnu If you are interested in doing a port, please contact the glibc maintainers; see https://www.gnu.org/software/libc/ for more information. See the file INSTALL to find out how to configure, build, and install the GNU C Library. You might also consider reading the WWW pages for the C library at https://www.gnu.org/software/libc/. The GNU C Library is (almost) completely documented by the Texinfo manual found in the `manual/' subdirectory. The manual is still being updated and contains some known errors and omissions; we regret that we do not have the resources to work on the manual as much as we would like. For corrections to the manual, please file a bug in the `manual' component, following the bug-reporting instructions below. Please be sure to check the manual in the current development sources to see if your problem has already been corrected. Please see https://www.gnu.org/software/libc/bugs.html for bug reporting information. We are now using the Bugzilla system to track all bug reports. This web page gives detailed information on how to report bugs properly. The GNU C Library is free software. See the file COPYING.LIB for copying conditions, and LICENSES for notices about a few contributions that require these additional notices to be distributed. License copyright years may be listed using range notation, e.g., 1996-2015, indicating that every year in the range, inclusive, is a copyrightable year that would otherwise be listed individually.