From 4945711ac0fe9f19ae0d358ae00db5c03485aa53 Mon Sep 17 00:00:00 2001 From: Android Partner Docs Date: Thu, 28 Jun 2018 10:08:47 -0700 Subject: Docs: Changes to source.android.com - 202498507 Devsite localized content from translation request 944914. by Android Partner Docs - 202368991 Document seccomp crashes. by Android Partner Docs - 202365193 Devsite localized content from translation request 941016. by Android Partner Docs - 202334002 Devsite localized content from translation request 944913. by Android Partner Docs - 202333988 Devsite localized content from translation request 944152. by Android Partner Docs - 202307420 Update Implementing Vulkan page. by Android Partner Docs - 202218233 The -j64 seems unrealistic for most users. Bumped it dow... by Gina Dimino - 202200614 Moving Treble content to main file (and removing treble f... by Heidi von Markham - 202192748 Clarify HIDL threading documentation. by Android Partner Docs - 202148581 Publish localized bulletins by Danielle Roberts - 202141713 Devsite localized content from translation request 937937. by Android Partner Docs - 202141703 Devsite localized content from translation request 941621. by Android Partner Docs - 202141693 Devsite localized content from translation request 936854. by Android Partner Docs - 202070722 Automated g4 rollback of changelist 182578621. by Christina Nguyen - 202039586 Noting the need for upstream patches to some projects. by Clay Murphy - 202035931 Devsite localized content from translation request 942523. by Android Partner Docs - 201978491 Devsite localized content from translation request 940149. by Android Partner Docs - 201749091 UpdatingHAL references/adding HIDL references by Android Partner Docs - 201700681 Devsite localized content from translation request 940151. by Android Partner Docs - 201700650 Devsite localized content from translation request 941012. by Android Partner Docs - 201700579 Devsite localized content from translation request 942527. by Android Partner Docs - 201700572 Devsite localized content from translation request 940150. by Android Partner Docs - 201700538 Devsite localized content from translation request 932858. by Android Partner Docs - 201700524 Devsite localized content from translation request 943117. by Android Partner Docs - 201700504 Devsite localized content from translation request 943114. by Android Partner Docs - 201537155 Devsite localized content from translation request 937234. by Android Partner Docs - 201537147 Devsite localized content from translation request 941017. by Android Partner Docs - 201532584 HAL to HIDL (change to "master" directory) by Android Partner Docs - 201376845 Devsite localized content from translation request 910444. by Android Partner Docs - 201371305 Devsite localized content from translation request 925769. by Android Partner Docs - 201371295 Devsite localized content from translation request 938920. by Android Partner Docs - 201264243 Removing version from VTS Codelab and O references. by Heidi von Markham - 201207845 Add measurements for version 8.x on Nexus 5X, Nexus 6P, P... by Android Partner Docs - 201195333 Devsite localized content from translation request 937940. by Android Partner Docs - 201028550 Changed "Functional patches" table description in Pixel b... by Android Partner Docs - 201021773 Devsite localized content from translation request 939440. by Android Partner Docs - 201021757 Devsite localized content from translation request 939442. by Android Partner Docs - 200732813 Devsite localized content from translation request 934614. by Android Partner Docs - 200732804 Devsite localized content from translation request 910442. by Android Partner Docs - 200625210 Updating warning about Valgrind deprecation by Heidi von Markham - 200618019 Simple fix to removing misleading Git images by Heidi von Markham - 200581373 Partner Security Updates and Resources Page has wrong OS ... by Android Partner Docs - 200553261 Devsite localized content from translation request 936855. by Android Partner Docs - 200553240 Devsite localized content from translation request 928419. by Android Partner Docs - 200553234 Devsite localized content from translation request 928433. by Android Partner Docs - 200553227 Devsite localized content from translation request 938813. by Android Partner Docs - 200428587 Add link to CTS downloads page. by Kenneth Lau - 200422176 Update CTS/CTS-Verifier downloads for CTS-Jun-2018 Releases by Android Partner Docs - 200409107 Devsite localized content from translation request 931899. by Android Partner Docs - 200289107 Android 7 -> Android 7.x and earlier; Android 8 -> Androi... by Android Partner Docs - 200275031 Replace index.html with _index.yaml. by Android Partner Docs - 200263644 Replace HAL paths with HIDL (B/78915061): In URLs, change... by Android Partner Docs - 200159329 Hide star ratings to fix layout. by Android Partner Docs - 200062417 Devsite localized content from translation request 915905. by Android Partner Docs - 200062406 Devsite localized content from translation request 932855. by Android Partner Docs - 200062403 Devsite localized content from translation request 936857. by Android Partner Docs - 200062395 Devsite localized content from translation request 924210. by Android Partner Docs - 199872446 add a 1 to the end of researchers twitter handle by Android Partner Docs - 199852050 Change Nexus > Pixel/ Nexus by Danielle Roberts - 199829857 Devsite localized content from translation request 932861. by Android Partner Docs - 199829853 Devsite localized content from translation request 931901. by Android Partner Docs - 199829847 Devsite localized content from translation request 928418. by Android Partner Docs - 199826612 Add stayres@ to bulletin localization file by Danielle Roberts PiperOrigin-RevId: 202498507 Change-Id: I3cf1b347a519ecff7960a159cdc57b35306435cf --- en/devices/architecture/hidl-cpp/index.html | 22 ++- en/devices/architecture/hidl/threading.html | 10 + .../architecture/images/treble_blog_after.png | Bin 16439 -> 15325 bytes .../architecture/images/treble_blog_before.png | Bin 19832 -> 18573 bytes en/devices/architecture/index.html | 208 ++++++++++++++++----- en/devices/architecture/treble.html | 92 --------- 6 files changed, 189 insertions(+), 143 deletions(-) delete mode 100644 en/devices/architecture/treble.html (limited to 'en/devices/architecture') diff --git a/en/devices/architecture/hidl-cpp/index.html b/en/devices/architecture/hidl-cpp/index.html index 28c4aa0a..15098178 100644 --- a/en/devices/architecture/hidl-cpp/index.html +++ b/en/devices/architecture/hidl-cpp/index.html @@ -83,7 +83,7 @@ HAL files and is a good reference). When transferring over HALs from 
 PACKAGE=android.hardware.nfc@1.0
 LOC=hardware/interfaces/nfc/1.0/default/
-make hidl-gen -j64
+m -j hidl-gen
 hidl-gen -o $LOC -Lc++-impl -randroid.hardware:hardware/interfaces \
     -randroid.hidl:system/libhidl/transport $PACKAGE
 hidl-gen -o $LOC -Landroidbp-impl -randroid.hardware:hardware/interfaces \
@@ -117,19 +117,29 @@ a binderized service. Example daemon code (for pure binderized service):

 
 
 int main(int /* argc */, char* /* argv */ []) {
+    // This function must be called before you join to ensure the proper
+    // number of threads are created. The threadpool will never exceed
+    // size one because of this call.
+    ::android::hardware::configureRpcThreadpool(1 /*threads*/, true /*willJoin*/);
+
     sp nfc = new Nfc();
     const status_t status = nfc->registerAsService();
     if (status != ::android::OK) {
         return 1; // or handle error
     }
-    // join pool or do other things
+
+    // Adds this thread to the threadpool, resulting in one total
+    // thread in the threadpool. We could also do other things, but
+    // would have to specify 'false' to willJoin in configureRpcThreadpool.
+    ::android::hardware::joinRpcThreadpool();
+    return 1; // joinRpcThreadpool should never return
 }
 

 
-
This daemon should live in $PACKAGE + "-service" (for example,
-android.hardware.nfc@1.0-service). The
-sepolicy for a specific class
-of HALs is the attribute hal_<module> (for instance,
+
This daemon usually lives in $PACKAGE + "-service-suffix" (for
+example, android.hardware.nfc@1.0-service), but it could be anywhere.
+The sepolicy for a specific
+class of HALs is the attribute hal_<module> (for instance,
 hal_nfc). This attribute must be applied to the daemon that runs a
 particular HAL (if the same process serves multiple HALs, multiple attributes
 can be applied to it).

diff --git a/en/devices/architecture/hidl/threading.html b/en/devices/architecture/hidl/threading.html
index 059b61d4..5b8fa038 100644
--- a/en/devices/architecture/hidl/threading.html
+++ b/en/devices/architecture/hidl/threading.html
@@ -54,6 +54,16 @@ simultaneously or out of order by a server with more than one thread, and
 oneway calls may be processed concurrently with a subsequent
 blocking call.

 
+
Multiple nested calls will be sent on the same hwbinder thread. For instance,
+if a process (A) makes a synchronous call from a hwbinder thread into process (B),
+and then process (B) makes a synchronous call back into process (A), the call will
+be executed on the original hwbinder thread in (A) which is blocked on the original
+call. This optimization makes it possible to have a single threaded server able to
+handle nested calls, but it does not extend to cases where the calls travel through
+another sequence of IPC calls. For instance, if process (B) had made a
+binder/vndbinder call which called into a process (C) and then process (C) calls
+back into (A), it cannot be served on the original thread in (A).

+
 
Server threading model

 
Except for passthrough mode, server implementations of HIDL interfaces live
 in a different process than the client and need one or more threads waiting for
diff --git a/en/devices/architecture/images/treble_blog_after.png b/en/devices/architecture/images/treble_blog_after.png
index 9eb06de4..ab2d05f0 100644
Binary files a/en/devices/architecture/images/treble_blog_after.png and b/en/devices/architecture/images/treble_blog_after.png differ
diff --git a/en/devices/architecture/images/treble_blog_before.png b/en/devices/architecture/images/treble_blog_before.png
index 4980f06b..c94d7638 100644
Binary files a/en/devices/architecture/images/treble_blog_before.png and b/en/devices/architecture/images/treble_blog_before.png differ
diff --git a/en/devices/architecture/index.html b/en/devices/architecture/index.html
index 592198ff..da16afb1 100644
--- a/en/devices/architecture/index.html
+++ b/en/devices/architecture/index.html
@@ -28,54 +28,172 @@ Android system architecture contains the following components:
 

 
 
+
Figure 1. Android system architecture

+
+
    
+
  • 
+    Application framework. The application framework is used
+    most often by application developers. As a hardware developer, you should be
+    aware of developer APIs as many map directly to the underlying HAL
+    interfaces and can provide helpful information about implementing drivers.
+
    • 
+
  • 
+    Binder IPC. The Binder Inter-Process Communication (IPC)
+    mechanism allows the application framework to cross process boundaries and
+    call into the Android system services code. This enables high level
+    framework APIs to interact with Android system services. At the application
+    framework level, this communication is hidden from the developer and things
+    appear to "just work".
+
    • 
+
  • 
+    System services. System services are modular, focused
+    components such as Window Manager, Search Service, or Notification Manager.
+    Functionality exposed by application framework APIs communicates with system
+    services to access the underlying hardware. Android includes two groups of
+    services: system (such as Window Manager and Notification Manager)
+    and media (services involved in playing and recording media).
+
    • 
+
  • 
+    Hardware abstraction layer (HAL). A HAL defines a standard
+    interface for hardware vendors to implement, which enables Android to be
+    agnostic about lower-level driver implementations. Using a HAL allows you to
+    implement functionality without affecting or modifying the higher level
+    system. HAL implementations are packaged into modules and loaded by the
+    Android system at the appropriate time. For details, see
+    Hardware Abstraction Layer
+    (HAL).
+
    • 
+
  • 
+    Linux kernel. Developing your device drivers is similar to
+    developing a typical Linux device driver. Android uses a version of the
+    Linux kernel with a few special additions such as Low Memory Killer (a
+    memory management system that is more aggressive in preserving memory), wake
+    locks (a
+    PowerManager
+    system service), the Binder IPC driver, and other features important for a
+    mobile embedded platform. These additions are primarily for system
+    functionality and do not affect driver development. You can use any version
+    of the kernel as long as it supports the required features (such as the
+    binder driver). However, we recommend using the latest version of the
+    Android kernel. For details, see
+    Building Kernels.
+
    • 
+

+
+
HAL interface definition language (HIDL)

 
-
Figure 1. Android system architecture

-
-
Application framework

-
-
The application framework is used most often by application developers. As a
-hardware developer, you should be aware of developer APIs as many map directly
-to the underlying HAL interfaces and can provide helpful information about
-implementing drivers.

-
-
Binder IPC

-
The Binder Inter-Process Communication (IPC) mechanism allows the application
-framework to cross process boundaries and call into the Android system services
-code. This enables high level framework APIs to interact with Android system
-services. At the application framework level, this communication is hidden from
-the developer and things appear to "just work".

-
-
System services

-
System services are modular, focused components such as Window Manager,
-Search Service, or Notification Manager. Functionality exposed by application
-framework APIs communicates with system services to access the underlying
-hardware. Android includes two groups of services: system (such as
-Window Manager and Notification Manager) and media (services involved
-in playing and recording media).

-
-
Hardware abstraction layer (HAL)

-
A HAL defines a standard interface for hardware vendors to implement,
-which enables Android to be agnostic about lower-level driver implementations.
-Using a HAL allows you to implement functionality without affecting or modifying
-the higher level system. HAL implementations are packaged into modules and
-loaded by the Android system at the appropriate time. For details, see
-Hardware Abstraction Layer (HAL).
+

+    Android 8.0 re-architected the Android OS framework (in a project known as
+    Treble) to make it easier, faster, and less costly for
+    manufacturers to update devices to a new version of Android. In this new
+    architecture, the HAL interface definition language (HIDL, pronounced
+    "hide-l") specifies the interface between a HAL and its users, enabling the
+    Android framework to be replaced without rebuilding the HALs.
+

+
+
+
+

+    HIDL separates the vendor implementation (device-specific, lower-level
+    software written by silicon manufacturers) from the Android OS framework via
+    a new vendor interface. Vendors or SOC makers build HALs once and place them
+    in a /vendor partition on the device; the framework, in its own
+    partition, can then be replaced with an
+    over-the-air (OTA) update without
+    recompiling the HALs.
+

+

+    The difference between the legacy Android architecture and the current,
+    HIDL-based architecture is in the use of the vendor interface:
+

+
+
    
+
  • 
+    In Android 7.x and earlier, no formal vendor interface exists, so device
+    makers must update large portions of the Android code to move a device to a
+    newer version of Android:

    
+
+
+
    Figure 2. Legacy Android update
+environment
    
+
    • 
+
  • 
+    In Android 8.0 and higher, a new stable vendor interface provides access to
+    the hardware-specific parts of Android, so device makers can deliver
+    new Android releases simply by updating the Android OS
+    framework—without additional work required from the silicon
+    manufacturers:

    
+
+
+
    Figure 3. Current Android update
+environment
    
+
    • 
+

+
+

+    All new devices launching with Android 8.0 and higher can take advantage of
+    the new architecture. To ensure forward compatibility of vendor
+    implementations, the vendor interface is validated by the
+    Vendor Test Suite (VTS), which is
+    analogous to the Compatibility Test Suite
+    (CTS). You can use VTS to automate HAL and OS kernel testing in both
+    legacy and current Android architectures.
+

+
+
Architecture resources

+
+

+    For details on the Android architecture, see the following sections:
 

 
-
Linux kernel

-
Developing your device drivers is similar to developing a typical Linux
-device driver. Android uses a version of the Linux kernel with a few special
-additions such as Low Memory Killer (a memory management system that is more
-aggressive in preserving memory), wake locks (a
-
-PowerManager system service), the Binder IPC driver, and
-other features important for a mobile embedded platform. These additions are
-primarily for system functionality and do not affect driver development.

-
-
You can use any version of the kernel as long as it supports the required
-features (such as the binder driver). However, we recommend using the latest
-version of the Android kernel. For details, see
-Building Kernels.

+
    
+
  • 
+    HAL Types. Describes
+    binderized, passthrough, Same-Process (SP), and legacy HALs.
+
    • 
+
  • 
+    HIDL (General). Contains
+    general information about the interface between a HAL and its users.
+
    • 
+
  • 
+    HIDL (C++). Contains
+    details for creating C++ implementations of HIDL interfaces.
+
    • 
+
  • 
+    HIDL (Java).
+    Contains details about the Java frontend for HIDL interfaces.
+
    • 
+
  • 
+    ConfigStore HAL.
+    Describes APIs for accessing read-only configuration items used to configure
+    the Android framework.
+
    • 
+
  • 
+    Device Tree Overlays.
+    Provides details on using device tree overlays (DTOs) in Android.
+
    • 
+
  • 
+    Vendor Native Development
+    Kit (VNDK). Describes the set of vendor-exclusive libraries for
+    implementing vendor HALs.
+
    • 
+
  • 
+    Vendor Interface Object
+    (VINTF). Describes the objects that aggregate relevant information about
+    a device and make that information available through a queryable API.
+
    • 
+
  • 
+    SELinux for Android
+    8.0. Details SELinux changes and customizations.
+
    • 
+

 
   
 
diff --git a/en/devices/architecture/treble.html b/en/devices/architecture/treble.html
deleted file mode 100644
index ca3c4086..00000000
--- a/en/devices/architecture/treble.html
+++ /dev/null
@@ -1,92 +0,0 @@
-
-  
-    Treble
-    
-    
-  
-  
-  
-
-
-
The Android 8.0 release includes Project Treble, a major re-architect
-of the Android OS framework designed to make it easier, faster, and less costly
-for manufacturers to update devices to a new version of Android. Treble is for
-all new devices launching with Android 8.0 and beyond (the new architecture is
-already running on the Developer Preview for Pixel phones).

-
-
About Android updates

-
Project Treble separates the vendor implementation (device-specific,
-lower-level software written by silicon manufacturers) from the Android OS
-framework via a new vendor interface.

-
-
In Android 7.x and earlier, no formal vendor interface exists so device
-makers must update large portions of the Android code to move a device to a
-newer version of Android:

-
-
-
-
Figure 1. Pre-Treble Android update
-environment

-
-
With Treble, a new stable vendor interface provides access to the
-hardware-specific parts of Android, enabling device makers to deliver new
-Android releases simply by updating the Android OS framework—without any
-additional work required from the silicon manufacturers:

-
-
-
-
Figure 2. Treble Android update
-environment

-
-
Testing Treble

-
To ensure forward compatibility of vendor implementations, the new vendor
-interface is validated by the Vendor Test
-Suite (VTS), which is analogous to the
-Compatibility Test Suite (CTS). You can use
-VTS to automate HAL and OS kernel testing in both pre-Treble and Treble
-environments.

-
-
Treble resources

-
For details on the new Treble architecture, see the following sections:

-
    
-
  • HAL Types. Describes
-binderized, passthrough, Same-Process (SP), and legacy HALs.
    • 
-
  • HIDL (General).
-Contains general information about the HAL interface definition language (HIDL,
-pronounced "hide-l"), which is an interface description language (IDL) to
-specify the interface between a HAL and its users.
    • 
-
  • HIDL (C++). Contains
-details for creating C++ implementations of HIDL interfaces.
    • 
-
  • HIDL (Java).
-Contains details about the Java frontend for HIDL interfaces.
    • 
-
  • ConfigStore HAL.
-Describes the ConfigStore HAL, which provides a set of APIs for accessing
-read-only configuration items used to configure the Android framework.
    • 
-
  • Device Tree Overlays.
-Provides details on using device tree overlays (DTOs) in Android.
    • 
-
  • Vendor Native Development
-Kit (VNDK). Describes the VNDK, which is a set of libraries exclusively for
-vendors to implement their HALs.
    • 
-
  • Vendor Interface Object
-(VINTF). VINTF objects aggregate relevant information about a device and
-make that information available through a queryable API.
    • 
-
  • SELinux for Android
-8.0. Details SELinux changes and customizations.
    • 
-

-
-  
-
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