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The current BR2_GCC_ENABLE_TLS can cause users to make incorrect choices, and is not very useful. This options allows to decide whether we pass --enable-tls or --disable-tls to gcc, to enable or disable support for Thread Local Storage. Its behavior is: - The option is default to "y" but only exists if we're using uClibc/NPTL or glibc. - When we're using uClibc, the option can be disabled. So, in practice, this means that currently: - TLS support is always on for glibc - TLS support is on by default for uClibc/NPTL, but can be disabled in the configuration. This is in fact bad and causes the build failure reported in bug #7424 (this bug is still reproducible on master) - TLS support is always disabled for uClibc/no-thread and uClibc/linuxthreads. - TLS support is always disabled for musl. This does not cause any build failure, but musl can use TLS support, and therefore be more efficient. According to http://www.openwall.com/lists/musl/2012/10/04/1, "Note that if you've been building gcc with --disable-tls, __thread was already working but gets emulated (very poorly; it's slow and will abort() if it runs out of memory) through libgcc.". So, this commit completely removes the BR2_GCC_ENABLE_TLS and instead makes the right choice inside gcc.mk directly: - TLS support enabled for glibc, musl and uClibc/NPTL - TLS support in other cases, i.e uClibc/no-thread and uClibc/linuxthreads. We have intentionally *not* added the option to Config.in.legacy. Indeed, the new behavior is *exactly* the same as the older behavior, with the exception of: - People can no longer disable TLS support in uClibc/NPTL, which was anyway causing a build failure and therefore was not used. - TLS support is now enabled on musl, but people using musl already had BR2_GCC_ENABLE_TLS not set, so they wouldn't get the legacy warning. Fixes bug #7424. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be> |
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| docs | ||
| fs | ||
| linux | ||
| package | ||
| support | ||
| system | ||
| toolchain | ||
| .defconfig | ||
| .gitignore | ||
| CHANGES | ||
| Config.in | ||
| Config.in.legacy | ||
| COPYING | ||
| Makefile | ||
| Makefile.legacy | ||
| README | ||
Buildroot is a simple, efficient and easy-to-use tool to generate embedded Linux systems through cross-compilation. The documentation can be found in docs/manual. You can generate a text document with 'make manual-text' and read output/docs/manual/manual.text. Online documentation can be found at http://buildroot.org/docs.html To build and use the buildroot stuff, do the following: 1) run 'make menuconfig' 2) select the target architecture and the packages you wish to compile 3) run 'make' 4) wait while it compiles 5) find the kernel, bootloader, root filesystem, etc. in output/images You do not need to be root to build or run buildroot. Have fun! Buildroot comes with a basic configuration for a number of boards. Run 'make list-defconfigs' to view the list of provided configurations. Please feed suggestions, bug reports, insults, and bribes back to the buildroot mailing list: buildroot@buildroot.org You can also find us on #buildroot on Freenode IRC. If you would like to contribute patches, please read https://buildroot.org/manual.html#submitting-patches