mainlining shenanigans
4767b9ad7d
As reported by kbuild test robot, the optimized SHA3 C implementation compiles to mn10300 code that uses a disproportionate amount of stack space, i.e., crypto/sha3_generic.c: In function 'keccakf': crypto/sha3_generic.c:147:1: warning: the frame size of 1232 bytes is larger than 1024 bytes [-Wframe-larger-than=] As kindly diagnosed by Arnd, this does not only occur when building for the mn10300 architecture (which is what the report was about) but also for h8300, and builds for other 32-bit architectures show an increase in stack space utilization as well. Given that SHA3 operates on 64-bit quantities, and keeps a state matrix of 25 64-bit words, it is not surprising that 32-bit architectures with few general purpose registers are impacted the most by this, and it is therefore reasonable to implement a workaround that distinguishes between 32-bit and 64-bit architectures. Arnd figured out that taking the round calculation out of the loop, and inlining it explicitly but only on 64-bit architectures preserves most of the performance gain achieved by the rewrite, and also gets rid of the excessive use of stack space. Reported-by: kbuild test robot <fengguang.wu@intel.com> Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> |
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| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.