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Linux mainline fork with MSM8998 patches | https://mainline.space | Currently supported devices: OnePlus 5/5T, Xiaomi Mi 6, F(x)tec Pro¹ (2019 QX1000 model) & Sony Xperia XZ Premium (UNTESTED!)
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Jinbum Park b26d07a0f5 ARM: 8742/1: Always use REFCOUNT_FULL 
refcount_t overflow detection is implemented as two way.

1. REFCOUNT_FULL

- It means the full refcount_t implementation
  which has validation but is slightly slower.
- (fd25d19f6b ("locking/refcount:
  Create unchecked atomic_t implementation"))

2. ARCH_HAS_REFCOUNT

- refcount_t overflow detection can be optimized
  via an arch-dependent way.
- It is based on atomic_t infrastructure
  with some instruction added for detection.
- It is faster than REFCOUNT_FULL,
  as fast as unprotected atomic_t infrastructure.
- (7a46ec0e2f ("locking/refcounts, x86/asm:
  Implement fast refcount overflow protection"))

ARCH_HAS_REFCOUNT has implemented for x86,
not implemented for others.

In the case of arm64,
Will Deacon said he didn't want the specialized
"fast but technically incomplete" refcounting as seen with x86's.

But rather to set REFCOUNT_FULL by default
because no one could point to real-world performance impacts with
REFCOUNT_FULL vs unprotected atomic_t infrastructure.

This is the reason arm64 ended up enabling REFCOUNT_FULL.
(4adcec1164 ("arm64: Always use REFCOUNT_FULL"))

As with the decision of arm64,
arm can set REFCOUNT_FULL by default.

Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jinbum Park <jinb.park7@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2018-01-21 15:32:26 +00:00
arch ARM: 8742/1: Always use REFCOUNT_FULL 2018-01-21 15:32:26 +00:00
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MAINTAINERS ARM: 8727/1: MAINTAINERS: Update brcmstb entries to cover B15 code 2017-12-17 22:15:39 +00:00
Makefile
README

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.