739003c642
We don't need to check for MTE support before checking the flag because it can only be set if the hardware supports MTE. As a result we can unconditionally check the flag bit which is expected to be in a register and therefore the check can be done in a single instruction instead of first needing to load the hwcaps. On a DragonBoard 845c with a kernel built with CONFIG_ARM64_MTE=y with the powersave governor this reduces the cost of a kernel entry/exit (invalid syscall) from 465.1ns to 463.8ns. Signed-off-by: Peter Collingbourne <pcc@google.com> Link: https://linux-review.googlesource.com/id/If4dc3501fd4e4f287322f17805509613cfe47d24 Link: https://lore.kernel.org/r/20201118032051.1405907-1-pcc@google.com [catalin.marinas@arm.com: remove IS_ENABLED(CONFIG_ARM64_MTE)] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> |
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.