9ae1e990f1
The GCC specific __attribute__((optimize)) attribute does not what is commonly expected and is explicitly recommended against using in production code by the GCC people. Unlike what is often expected, it doesn't add to the optimization flags, but it fully replaces them, loosing any and all optimization flags provided by the compiler commandline. The only guaranteed upon means of inhibiting tail-calls is by placing a volatile asm with side-effects after the call such that the tail-call simply cannot be done. Given the original commit wasn't specific on which calls were the problem, this removal might re-introduce the problem, which can then be re-analyzed and cured properly. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Miguel Ojeda <ojeda@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ian Rogers <irogers@google.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Kook <keescook@chromium.org> Cc: Martin Liška <mliska@suse.cz> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lore.kernel.org/lkml/20201028081123.GT2628@hirez.programming.kicks-ass.net Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.