b5df5b8307
The low-level idle code in arch_cpu_idle() and its callees runs at a time where where portions of the kernel environment aren't available. For example, RCU may not be watching, and lockdep state may be out-of-sync with the hardware. Due to this, it is not sound to instrument this code. We generally avoid instrumentation by marking the entry functions as `noinstr`, but currently this doesn't inhibit KCOV instrumentation. Prevent this by factoring these functions into a new idle.c so that we can disable KCOV for the entire compilation unit, as is done for the core idle code in kernel/sched/idle.c. We'd like to keep instrumentation of the rest of process.c, and for the existing code in cpuidle.c, so a new compilation unit is preferable. The arch_cpu_idle_dead() function in process.c is a cpu hotplug function that is safe to instrument, so it is left as-is in process.c. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Marc Zyngier <maz@kernel.org> Cc: James Morse <james.morse@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20210607094624.34689-21-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org>
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.