Many people do think that the hardware knowledge is only in the kernel.
This is to prevent confusion.
Signed-off-by: Denis 'GNUtoo' Carikli <gnu...@no-log.org>
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freedom-privacy-security-issues.php | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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b/freedom-privacy-security-issues.php
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@@ -7,7 +7,7 @@
<p>Mobile devices such as phones and tablets are taking
and increasingly important part in our computing, hence they are particularly
subject to freedom and security concerns. These devices are actually full
computers with powerful hardware, running complete operating systems that allow
for updates, software changes and installable applications: this makes it easy
to run <a href="//www.gnu.org/philosophy/free-sw.html">free software</a> on
them. Mobile devices are often used for communications and provide hardware
features that are sensitive when it comes to privacy and security: GPS, camera,
microphone, etc, in addition to storing the user's data. Hence, they are
particularly subject to being used to spy on the user.</p>
<h3>A simplified overview of mobile devices</h3>
<p><a
href="images/freedom-privacy-security-issues/hardware.png"
data-lightbox="overview" data-title="Hardware-side overview"><img
src="images/freedom-privacy-security-issues/hardware.png" alt="Hardware-side
overview" style="width: 250px; float: left;"/></a>On the hardware side, mobile
devices are built with a system on a chip (SoC) that includes a processor (CPU)
and various other fundamental components, around which are found various
integrated circuits, memory (RAM), storage, user input/output (I/O), etc. When
the device is telephony-enabled, it also features a modem, which is the
component in charge of dealing with the mobile telephony network. Nowadays, it
is usually has a powerful processor, with dedicated memory and sometimes
storage.</p>
- <p>Regarding the software side of things on mobile
devices, the main CPU (inside the SoC) starts by executing code located inside
the silicon. If this is an ARM CPU, that code will be ARM instructions. This
code is known as the botrom. It will look up various places such as NAND, eMMC
or MMC (sd/micro sd card) storage, depending on the hardware configuration, to
load a bootloader. The bootloader, which is in fact often split in different
stages, is in charge of bringing up and configuring various aspects of the
hardware and eventually starting the operating system by loading and running
its kernel.<br /><a href="images/freedom-privacy-security-issues/software.png"
data-lightbox="overview" data-title="Software-side overview"><img
src="images/freedom-privacy-security-issues/software.png" alt="Software-side
overview" style="width: 250px; float: right;"/></a>The kernel itself, among
other things, deals with the hardware directly and provides ways for other
programs (running i
n user-s
pace) to access it. In user-space, hardware abstraction layers are programs
specific to each device that know how to properly drive the hardware. They use
the kernel to communicate back and forth with the hardware and implement the
proper protocols for it.<br /><br />The actual knowledge of how to drive the
hardware is split between the kernel and the hardware abstraction layer
libraries: both are needed to make it work properly. Hardware abstraction
layers provide a generic interface for the framework to use. The framework
itself provides an interface for applications that is independent of the device
and the hardware. That way, applications can access hardware features through
the generic framework interface, which will call the hardware abstraction layer
libraries, ending up with the kernel communicating with the hardware.</p>
+ <p>Regarding the software side of things on mobile
devices, the main CPU (inside the SoC) starts by executing code located inside
the silicon. If this is an ARM CPU, that code will be ARM instructions. This
code is known as the botrom. It will look up various places such as NAND, eMMC
or MMC (sd/micro sd card) storage, depending on the hardware configuration, to
load a bootloader. The bootloader, which is in fact often split in different
stages, is in charge of bringing up and configuring various aspects of the
hardware and eventually starting the operating system by loading and running
its kernel.<br /><a href="images/freedom-privacy-security-issues/software.png"
data-lightbox="overview" data-title="Software-side overview"><img
src="images/freedom-privacy-security-issues/software.png" alt="Software-side
overview" style="width: 250px; float: right;"/></a>The kernel itself, among
other things, deals with the hardware directly and provides ways for other
programs (running i
n user-s
pace) to access it. In user-space, hardware abstraction layers are programs
specific to each device that know how to properly drive the hardware. They use
the kernel to communicate back and forth with the hardware and implement the
proper protocols for it.<br /><br />The actual knowledge of how to drive the
hardware is split between the kernel and the hardware abstraction layer
libraries: both are needed to make it work properly. Hardware abstraction
layers provide a generic interface for the framework to use. The framework
itself provides an interface for applications that is independent of the device
and the hardware. That way, applications can access hardware features through
the generic framework interface, which will call the hardware abstraction layer
libraries, ending up with the kernel communicating with the hardware. For
instance, when making a call, the dialer application will communicate with the
framework, which in turn will communicate with the hardware abstract
ion laye
r. That hardware abstraction layer will implement the protocol to speak with
the modem, and the Linux kernel will be responsible of permitting the
communication between the hardware abstraction layer and the modem.</p>
<p>Many other components of a mobile device also run
software in different forms. The various integrated circuits run small pieces
of dedicated software that are called firmwares. When the device is
telephony-enabled, there is also software running on the modem. Modern modems
are complex and run full operating systems.</p>
<h3>The current situation of freedom and
privacy/security on mobile devices</h3>
<p>A mobile device respecting the users' freedom would
have:<ul><li>Free hardware</li><li>Free firmwares</li><li>Free modem
system</li><li>Free bootrom and bootloader</li><li>Free system and
applications</li></ul>Regarding <a href="#free-hardware">free hardware</a>, it
doesn't quite exist as of today, or barely. Modifying hardware is nearly
impossible: new versions of the hardware have to be produced, and those are
expensive. While producing printed circuit boards (PCBs) costs a lot of money,
producing integrated circuits is out of reach. A few devices come with
schematics for the PCB, but that's usually as far as it gets. Hence,
totally-free hardware doesn't exist yet.</p>
--
2.7.2
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