Commit Graph

4 Commits

Author SHA1 Message Date
Norman Feske
eaac3cc1bd Revised API documentation
This patch curates the API documentation to become suitable for the
functional specificaton, which is partially generated from the header
files.
2015-04-09 16:04:46 +02:00
Norman Feske
e8336acafc base,os: Coding-style unification
Fixes #1432
2015-03-13 12:17:23 +01:00
Martin Stein
ec6c19a487 base: memory barriers in lock implementations
The memory barrier prevents the compiler from changing the program order
of memory accesses in such a way that accesses to the guarded resource
get outside the guarded stage. As cmpxchg() defines the start of the
guarded stage it also represents an effective memory barrier.

On x86, the architecture ensures to not reorder writes with older reads,
writes to memory with other writes (except in cases that are not
relevant for our locks), or read/write instructions with I/O
instructions, locked instructions, and serializing instructions.

However on ARM, the architectural memory model allows not only that
memory accesses take local effect in another order as their program
order but also that different observers (components that can access
memory like data-busses, TLBs and branch predictors) observe these
effects each in another order. Thus, a correct program order isn't
sufficient for a correct observation order. An additional architectural
preservation of the memory barrier is needed to achieve this.

Fixes #692
2014-11-28 12:02:34 +01:00
Norman Feske
ca971bbfd8 Move repositories to 'repos/' subdirectory
This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.

Issue #1082
2014-05-14 16:08:00 +02:00