Linux Standard Base Specification for the IA32 Architecture 1.1.0
Copyright © 2001 by Free Standards Group
This material may be distributed only subject to the terms and conditions set
forth in the Open Publication License, v1.0 or later (the latest version is
presently available at http://www.opencontent.org/openpub/) and provided that
neither the name of the Free Standards Group, the name of the Linux Standard
Base, nor the names of its contributors may be used to endorse or promote
derived works without specific prior written permission.
Portions of the text were taken from other copyrighted documents in accordance
with the respective license of those documents.
-------------------------------------------------------------------------------
Table of Contents
I. Introduction
1. Introduction
Introduction
Purpose
Related Standards
Related Implementations
Relevant Libraries
How to Use this Standard
Definitions
Terminology
II. Low Level System Information
2. Machine Interface
Processor Architecture
Data Representation
3. Function Calling Sequence
CPU Registers
Floating Point Registers
Stack Frame
Arguments
Return Values
4. Operating System Interface
Virtual Address Space
Processor Execution Mode
Exception Interface
Signal Delivery
5. Process Initialization
Special Registers
Process Stack (on entry)
Auxilliary Vectors
Environment
6. Coding Examples
Code Model Overview/Architecture Constraints
Position-Independent Fucntion Prologue
Data Objects
Function Calls
Branching
7. C Stack Frame
Variable Argument List
Dynamic Allocation of Stack Space
8. Debug Information
III. Object Format
9. ELF Header
Machine Information
10. Sections
Special Sections
Linux Special Sections
Section Types
Section Attribute Flags
Special Section Types
11. Symbol Table
12. Relocation
Relocation Types
IV. Program Loading and Dynamic Linking
13. Program Header
Types
Flags
14. Program Loading
15. Dynamic Linking
Program Intepreter/Dynamic Linker
Dynamic Section
Global Offset Table
Shared Object Dependencies
Function Addresses
Procedure Linkage Table
Initialization and Termination Functions
V. Base Libraries
16. Libraries
Interfaces for libc
Data Definitions for libc
Interfaces Definitions for libc
Interfaces for libm
Data Definitions for libm
A. Alphabetical Listing of Interfaces
libc
List of Tables
1-1. Related Standards
1-2. Related Implementations
1-3. Relevant Libraries
2-1. Scalar Types
10-1.
10-2.
16-1. libc Definition
16-2. libc - Standard Library Function Interfaces
16-3. libc - Language Support Function Interfaces
16-4. libm Definition
A-1. libc Function Interfaces
I. Introduction
Table of Contents
1. Introduction
-------------------------------------------------------------------------------
Chapter 1. Introduction
Introduction
This is version 1.1.0 of the Linux Standard Base Specification for the IA32
Architecture. An implementation of this version of the specification may not
claim to be an implementation of the Linux Standard Base unless it has
successfully completed the compliance process as defined by the Free Standards
Group.
-------------------------------------------------------------------------------
Purpose
The Linux Standard Base (LSB) defines a system interface for compiled
applications and a minimal environment for support of installation scripts. Its
purpose is to enable a uniform industry standard environment for high-volume
applications conforming to the LSB.
The LSB defines a binary interface for application programs that are compiled
and packaged for LSB-conforming implementations on many different hardware
architectures. Since a binary specification must include information specific
to the computer processor architecture for which it is intended, it is not
possible for a single document to specify the interface for all possible
LSB-conforming implementations. Therefore, the LSB is a family of
specifications, rather than a single one.
The LSB is composed of two basic parts: A common part of the specification
describes those parts of the interface that remain constant across all hardware
implementations of the LSB, and an architecture-specific part of the
specification describes the parts of the specification that are specific to a
particular processor architecture. Together, the generic LSB and the
architecture-specific supplement for a single hardware architecture provide a
complete interface specification for compiled application programs on systems
that share a common hardware architecture.
This document is the architecture-specific suppliment. It must be used in
conjunction with the generic LSB. This document provides architecture-specific
information that supplements the generic LSB as well as additional information
that is not found in the generic LSB.
This document should be used in conjunction with the documents it references.
This document enumerates the system components it includes, but descriptions of
those components may be included entirely or partly in this document, partly in
other documents, or entirely in other reference documents. For example, the
section that describes system service routines includes a list of the system
routines supported in this interface, formal declarations of the data
structures they use that are visible to applications, and a pointer to the
underlying referenced specification for information about the syntax and
semantics of each call. Only those routines not described in standards
referenced by this document, or extensions to those standards, are described in
the detail. Information referenced in this way is as much a part of this
document as is the information explicitly included here.
-------------------------------------------------------------------------------
Related Standards
The specifications listed below are referenced in whole or in part by the Linux
Standard Base. Such references may be normative or non-normative; a reference
to specification shall only be considered normative if it is explicitly cited
as such. The LSB may make normative references to a portion of these
specifications (that is, to define a specific function or group of functions);
in such cases, only the explicitly referenced portion of the specification is
to be considered normative.
Table 1-1. Related Standards
+-----------------------------------------------------------------------------+
|System V Application Binary Interface |http://www.caldera.com| |
|- DRAFT - 22 June 2000 |/developers/gabi/ | |
| |2000-07-17/ | |
| |contents.html | |
|--------------------------------------+----------------------+---------------|
|Filesystem Hierarchy Standard 2.2 |http:// | |
| |www.pathname.com/fhs/ | |
|--------------------------------------+----------------------+---------------|
|IEEE Standard for Binary |http://www.ieee.org/ |ANSI/IEEE |
|Floating-Point Arithmetic | |Standards |
| | |745-1985 and |
| | |854-1987 |
|--------------------------------------+----------------------+---------------|
|System V Application Binary Interface,|http://www.caldera.com| |
|Edition 4.1 |/developers/devspecs/ | |
| |gabi41.pdf | |
|--------------------------------------+----------------------+---------------|
|IA32 Architecture Software Developer's|http:// | |
|Manual Volume 1: Basic Architecture |developer.intel.com/ | |
| |design/pentiium4/ | |
| |manuals/24570.ht | |
|--------------------------------------+----------------------+---------------|
|IA32 Architecture Software Developer's|http:// | |
|Manual Volume 2: Instruction Set |developer.intel.com/ | |
|Reference |design/pentiium4/ | |
| |manuals/24571.ht | |
|--------------------------------------+----------------------+---------------|
|IA32 Architecture Software Developer's|http:// | |
|Manual Volume 3: System Programming |developer.intel.com/ | |
|Guide |design/pentiium4/ | |
| |manuals/24572.ht | |
|--------------------------------------+----------------------+---------------|
|System V Application Binary Interface |http://www.caldera.com| |
|- Intel386 Architecture Processor |/developers/devspecs/ | |
|Supplement |abi386-4.pdf | |
|--------------------------------------+----------------------+---------------|
|Itanium Architecture Software |http:// | |
|Developer's Manual Volume 1: |developer.intel.com/ | |
|Application Architecture |design/itanium/ | |
| |downloads/24531702 | |
|--------------------------------------+----------------------+---------------|
|Itanium Architecture Software |http:// | |
|Developer's Manual Volume 2: System |developer.intel.com/ | |
|Architecture |design/itanium/ | |
| |downloads/24531802 | |
|--------------------------------------+----------------------+---------------|
|Itanium Architecture Software |http:// | |
|Developer's Manual Volume 3: |developer.intel.com/ | |
|Instruction Set Reference |design/itanium/ | |
| |downloads/24531902 | |
|--------------------------------------+----------------------+---------------|
|Itanium Architecture Software |http:// | |
|Developer's Manual Volume 4: Itanium |developer.intel.com/ | |
|Processor Programmer's Guide |design/itanium/ | |
| |downloads/24532002 | |
|--------------------------------------+----------------------+---------------|
|Itanium(R) Software Conventions & |http:// | |
|Runtime Architecture Guide |developer.intel.com/ | |
| |design/ia-64/downloads| |
| |/245358.htm | |
|--------------------------------------+----------------------+---------------|
|ISO/IEC 9899: 1990, Programming | | |
|Languages --C | | |
|--------------------------------------+----------------------+---------------|
|ISO/IEC 9899: 1999, Programming | | |
|Languages --C | | |
|--------------------------------------+----------------------+---------------|
|Linux Assigned Names And Numbers |http://www.lanana.org/| |
|Authority | | |
|--------------------------------------+----------------------+---------------|
|Large File Support |http:// | |
| |www.UNIX-systems.org/ | |
| |version2/whatsnew/ | |
| |lfs20mar.html | |
|--------------------------------------+----------------------+---------------|
|Linux Standard Base |http:// | |
| |www.linuxbase.org/spec| |
| |/ | |
|--------------------------------------+----------------------+---------------|
|OpenGL® Application Binary Interface |http://oss.sgi.com/ | |
|for Linux |projects/ogl-sample/ | |
| |ABI/ | |
|--------------------------------------+----------------------+---------------|
|IEEE Std POSIX 1003.2-1992 (ISO/IEC |http://www.ieee.org/ | |
|9945-2:1993) | | |
|--------------------------------------+----------------------+---------------|
|POSIX 1003.1c |http://www.ieee.org/ | |
|--------------------------------------+----------------------+---------------|
|CAE Specification, May 1996, X/Open |http:// | |
|Curses, Issue 4, Version 2 (ISBN: |www.opengroup.org/ | |
|1-85912-171-3, C610), plus Corrigendum| | |
|U018 | | |
|--------------------------------------+----------------------+---------------|
|CAE Specification, January 1997, |http:// | |
|System Interface Definitions (XBD), |www.opengroup.org/ | |
|Issue 5 (ISBN: 1-85912-186-1, C605) | | |
|--------------------------------------+----------------------+---------------|
|CAE Specification, January 1997, |http:// | |
|Commands and Utilities (XCU), Issue 5 |www.opengroup.org/ | |
|(ISBN: 1-85912-191-8, C604) | | |
|--------------------------------------+----------------------+---------------|
|CAE Specification, February 1997, |http:// | |
|Networking Services (XNS), Issue 5 |www.opengroup.org/ | |
|(ISBN: 1-85912-165-9, C523) | | |
|--------------------------------------+----------------------+---------------|
|CAE Specification, January 1997, |http:// | |
|System Interfaces and Headers (XSH), |www.opengroup.org/ | |
|Issue 5 (ISBN: 1-85912-181-0, C606) | | |
|--------------------------------------+----------------------+---------------|
|The Single UNIX Specification Version |http:// | |
|1 (UNIX 95) System Interfaces & |www.opengroup.org/ | |
|Headers | | |
|--------------------------------------+----------------------+---------------|
|System V Interface Definition, Issue 3| |ISBN 0201566524|
|--------------------------------------+----------------------+---------------|
|System V Interface Definition,Fourth | | |
|Edition | | |
|--------------------------------------+----------------------+---------------|
|Double Buffer Extension Library |http://www.x.org/ | |
|--------------------------------------+----------------------+---------------|
|X Display Power Management Signaling |http://www.x.org/ | |
|(DPMS) Extension, Library | | |
|Specification | | |
|--------------------------------------+----------------------+---------------|
|X Record Extension Library |http://www.x.org/ | |
|--------------------------------------+----------------------+---------------|
|Security Extension Specification, |http://www.x.org/ | |
|Version 7.1 | | |
|--------------------------------------+----------------------+---------------|
|X Nonrectangular Window Shape |http://www.x.org/ | |
|Extension Library Version 1.0 | | |
|--------------------------------------+----------------------+---------------|
|MIT-SHM--The MIT Shared Memory |http://www.x.org/ | |
|Extension | | |
|--------------------------------------+----------------------+---------------|
|X Synchronization Extension Library |http://www.x.org/ | |
|--------------------------------------+----------------------+---------------|
|XTEST Extension Library |http://www.x.org/ | |
|--------------------------------------+----------------------+---------------|
|X11R6.4 X Inter-Client Exchange (ICE) |http://www.x.org/ | |
|Protocol | | |
|--------------------------------------+----------------------+---------------|
|X11R6.4 X11 Input Extension Library |http://www.x.org/ | |
|--------------------------------------+----------------------+---------------|
|X11R6.4 Xlib - C library |http://www.x.org/ | |
|--------------------------------------+----------------------+---------------|
|X/Open Portability Guide, Issue 4 |http:// | |
| |www.opengroup.org/ | |
|--------------------------------------+----------------------+---------------|
|X11R6.4 X Session Management Library |http://www.x.org/ | |
|--------------------------------------+----------------------+---------------|
|X11R.4 X Toolkit Intrinsics |http://www.x.org/ | |
|--------------------------------------+----------------------+---------------|
|zlib 1.1.3 Manual |http://www.gzip.org/ |See |
| |zlib/ | |
+-----------------------------------------------------------------------------+
-------------------------------------------------------------------------------
Related Implementations
The implementations listed here are referenced in whole or in part by the Linux
Standard Base when no formal specification is available.
Table 1-2. Related Implementations
+-----------------------------------------------------------------------------+
|BSD 4.4 Lite | | |
|version 2 | | |
|------------------+--------------------+-------------------------------------|
|GNU/Linux defacto |http://www.gnu.org/ | |
|standard | | |
|------------------+--------------------+-------------------------------------|
|RFC 1831 & 1832 |http://www.ietf.org/|Still need API reference, instead of |
| | |protocol reference |
|------------------+--------------------+-------------------------------------|
|RPM Package Format|http://www.rpmdp.org| |
|V3.0 |/rpmbook/ | |
+-----------------------------------------------------------------------------+
-------------------------------------------------------------------------------
Relevant Libraries
The libraries listed here shall be available on a Linux Standard Base system.
This list is an addition to the list in the general specification.
Table 1-3. Relevant Libraries
+--------------------------------+
|Library |Runtime Name |
|---------------+----------------|
|libm |libm.so.6 |
|---------------+----------------|
|libutil |libutil.so.1 |
|---------------+----------------|
|libc |libc.so.6 |
|---------------+----------------|
|libpthread |libpthread.so.0 |
|---------------+----------------|
|proginterp-ia32|/lib/ld-lsb.so.1|
|---------------+----------------|
|librt |librt.so.1 |
+--------------------------------+
These libraries will be in an implementation-dependent directory which the
dynamic linker will search by default.
-------------------------------------------------------------------------------
How to Use this Standard
The complete LSB specification is composed of a generic LSB specification and
this supplemental processor-specific specification. These two documents
constitute a specification that should be used in conjunction with the
publicly-available standards documents it references. The LSB enumerates the
system components it includes, but descriptions of those components may be
included entirely in the LSB, partly in the LSB and partly in other documents,
or entirely in other reference documents.
-------------------------------------------------------------------------------
Definitions
gLSB
This document.
LSB-Compliant Application
An application written to include only the system routines, commands, and
other resources included in this document, and that has been compiled into
an executable file that has the formats and characteristics specified for
such files in this document, and whose behavior complies, installs, and is
executed in the environment with the rules given in this document.
LSB-Conforming Implementation
An implementation that provides the binary system interface for
applications described in this document.
Non-LSB-Compliant Application
An application which has been written to include system routines, commands,
or other resources not included in this document, or which has been
compiled into a different from those specified here, or which does not
behave as specified in this document.
LSB Implementation Conformance
An implementation satisfying the following requirements:
1. The implementation shall implement fully the architecture described in
the hardware manual for the target processor architecture.
2. The implementation shall be capable of executing compiled applications
having the and using the system interfaces described in this document.
3. The implementation shall provide libraries containing the interfaces
specified by this document, and shall provide a dynamic linking
mechanism that allows these interfaces to be attached to applications
at runtime. All the interfaces shall behave as specified in the
normative references and requirements of this document.
4. The map of virtual memory provided by the implementation shall conform
to the requirements of this document.
5. The implementation's low-level behavior with respect to function call
linkage, system traps, signals, and other such activities shall conform
to the formats described in this document.
6. The compilation system shall compile source code into executable files
having the formats and characteristics specified in this document.
7. The implementation shall provide all of the mandatory interfaces in
their entirety.
8. The implementation may provide one or more of the optional interfaces.
Each optional interface that is provided shall be provided in its
entirety. The product documentation shall state which optional
interfaces are provided.
9. The implementation shall provide all files and utilities specified as
part of this document in the defined here and in other referenced
documents. All commands and utilities shall behave as required by this
document. The implementation shall also provide all mandatory
components of an application's runtime environment that are included or
referenced in this document.
10. The implementation, when provided with standard data formats and values
at a named interface, shall provide the behavior defined for those
values and data formats at that interface. However, a conforming
implementation may consist of components which are separately packaged
and/or sold. For example, a vendor of a conforming implementation might
sell the hardware, operating system, and windowing system as separately
packaged items.
11. The implementation may provide additional interfaces with different
names. It may also provide additional behavior corresponding to data
values outside the standard ranges, for standard named interfaces.
LSB Application Conformance
An application with the following characteristics:
1. Its executable files are either shell scripts or object files in the
defined for the Object File Format system interface.
2. Its object files participate in dynamic linking as defined in the
Program Loading and Linking System interface.
3. It employs only the instructions, traps, and other low-level facilities
defined in the Low-Level System interface as being for use by
applications.
4. If it requires any optional interface defined in this document in order
to be installed or to execute successfully, the requirement for that
optional interface is stated in the application's documentation.
5. It does not use any interface or data that is not required to be
provided by a conforming implementation, unless:
o If such an interface or data is supplied by another application
through direct invocation of that application during execution,
that application is in turn an LSB-compliant application.
o The use of that interface or data , as well as its source, is
identified in the documentation of the application.
6. It must not use any values for a named interface that are reserved for
vendor extensions.
A strictly conforming application does not require or use any interface,
facility, or implementation-defined extension that is not defined in this
document in order to be installed or to execute successfully.
Rationale
An LSB-compliant application is expected to have no dependencies on any
vendor extensions to this document. The most common such extensions are
additional function entry points and additional libraries other than the
ones defined in this document. If an application requires such extensions,
it is not portable, since other LSB-conforming implementations may not
provide those extensions.
An LSB-compliant application is required to use system services on the
implementation on which it is running, rather than importing system
routines from some other implementation. Thus, it must link dynamically to
any routines in the implementation that perform system traps to kernel
services.
It is to be expected that some applications may be companion applications
to other applications. For example, a query application may be a companion
to a database application; a preprocessor may be an adjunct to one or more
compilers; a data reformatter may convert data from one document manager to
another. In such cases, the application may or may not be LSB-compliant,
regardless of whether the other application on which it is dependent is
LSB-compliant. If such an application merely uses data produced by another
application, the application's compliance is independent of the other
application's compliance. If such an application actually invokes another
application during execution (as, for example, a third-party math library),
the invoking application is LSB-compliant only if it also constitutes a
LSB-compliant application in combination with the invoked application.
Shell Script
A file that is read by an interpreter (e.g., awk). The first line of the
shell script includes a reference to its interpreter binary.
-------------------------------------------------------------------------------
Terminology
can
Describes a permissible optional feature or behavior available to the user
or application. The feature or behavior is mandatory for an implementation
that conforms to this document. An application can rely on the existence of
the feature or behavior.
implementation-defined
Describes a value or behavior that is not defined by this document but is
selected by an implementor. The value or behavior may vary among
implementations that conform to this document. An application should not
rely on the existence of the value or behavior. An application that relies
on such a value or behavior cannot be assured to be portable across
conforming implementations. The implementor shall document such a value or
behavior so that it can be used correctly by an application.
Same as implementation-dependent.
may
Describes a feature or behavior that is optional for an implementation that
conforms to this document. An application should not rely on the existence
of the feature or behavior. An application that relies on such a feature or
behavior cannot be assured to be portable across conforming
implementations.
To avoid ambiguity, the opposite of may is expressed as need not, instead
of may not.
must
Describes a feature or behavior that is mandatory for an application or
user. An implementation that conforms to this document shall support this
feature or behavior.
shall
Describes a feature or behavior that is mandatory for an implementation
that conforms to this document. An application can rely on the existence of
the feature or behavior.
should
For an implementation that conforms to this document, describes a feature
or behavior that is recommended but not mandatory. An application should
not rely on the existence of the feature or behavior. An application that
relies on such a feature or behavior cannot be assured to be portable
across conforming implementations.
For an application, describes a feature or behavior that is recommended
programming practice for optimum portability.
undefined
Describes the nature of a value or behavior not defined by this document
which results from use of an invalid program construct or invalid data
input. The value or behavior may vary among implementations that conform to
this document. An application should not rely on the existence or validity
of the value or behavior. An application that relies on any particular
value or behavior cannot be assured to be portable across conforming
implementations.
unspecified
Describes the nature of a value or behavior not specified by this document
which results from use of a valid program construct or valid data input.
The value or behavior may vary among implementations that conform to this
document. An application should not rely on the existence or validity of
the value or behavior. An application that relies on any particular value
or behavior cannot be assured to be portable across conforming
implementations.
will
Same meaning as shall; shall is the preferred term.
II. Low Level System Information
Table of Contents
2. Machine Interface
3. Function Calling Sequence
4. Operating System Interface
5. Process Initialization
6. Coding Examples
7. C Stack Frame
8. Debug Information
-------------------------------------------------------------------------------
Chapter 2. Machine Interface
Processor Architecture
The IA32 Architecture is specified by the following documents
* Intel Architecture Software Developer's Manual, Volume 1: Basic
Architecture
* Intel Architecture Software Developer's Manual, Volume 2: Instruction Set
Reference Manual
* Intel Architecture Software Developer's Manual, Volume 3: System
Programming Guide
Only the features of the Intel486 processor instruction set may be assumed to
be present. An application is responsible for determining if any additional
instruction set features are available before using those additional features.
If a feature is not present, then the application may not use it.
Applications conforming to this specification must provide feedback to the user
if a feature that is required for correct execution of the application is not
present. Applications conforming to this specification should attempt to
execute in a diminished capacity if a required instruction set feature is not
present.
This specfication does not provide any performance guarantees of a conforming
system. A system conforming to this specification may be implemented in either
hardware or software.
-------------------------------------------------------------------------------
Data Representation
LSB-conforming applications shall use the data representation as defined in
Chapter 3 of the System V Application Binary Interface - Intel386 Architecture
Processor Supplement.
-------------------------------------------------------------------------------
Byte Ordering
-------------------------------------------------------------------------------
Fundamental Types
In addition to the fundamental types specified in Chapter 3 of the System V
Application Binary Interface - Intel386 Architecture, a 64 bit data type is
defined here.
Table 2-1. Scalar Types
+---------------------------------------------------------------------------+
|Type |C |sizeof|Alignment (bytes)|IntelI386 Architecture|
|--------+------------------+------+-----------------+----------------------|
| |long long | | | |
| |------------------|8 |4 |signed double word |
|Integral|signed long long | | | |
| |------------------+------+-----------------+----------------------|
| |unsigned long long|8 |4 |unsigned double word |
+---------------------------------------------------------------------------+
-------------------------------------------------------------------------------
Aggregates and Unions
-------------------------------------------------------------------------------
Bit Fields
-------------------------------------------------------------------------------
Chapter 3. Function Calling Sequence
LSB-conforming applications shall use the function calling sequence as defined
in Chapter 3 of the System V Application Binary Interface - Intel386
Architecture Processor Supplement.
-------------------------------------------------------------------------------
CPU Registers
-------------------------------------------------------------------------------
Floating Point Registers
-------------------------------------------------------------------------------
Stack Frame
-------------------------------------------------------------------------------
Arguments
-------------------------------------------------------------------------------
Integral/Pointer
-------------------------------------------------------------------------------
Floating Point
-------------------------------------------------------------------------------
Struct and Union Point
-------------------------------------------------------------------------------
Variable Arguments
-------------------------------------------------------------------------------
Return Values
-------------------------------------------------------------------------------
Void
-------------------------------------------------------------------------------
Integral/Pointer
-------------------------------------------------------------------------------
Floating Point
-------------------------------------------------------------------------------
Struct and Union Point
-------------------------------------------------------------------------------
Chapter 4. Operating System Interface
LSB-conforming applications shall use the Operating System Interfaces as
defined in Chapter 3 of the System V Application Binary Interface - Intel386
Architecture Processor Supplement.
-------------------------------------------------------------------------------
Virtual Address Space
-------------------------------------------------------------------------------
Page Size
-------------------------------------------------------------------------------
Virtual Address Assignments
-------------------------------------------------------------------------------
Managing the PRocess Stack
-------------------------------------------------------------------------------
Coding Guidlines
-------------------------------------------------------------------------------
Processor Execution Mode
-------------------------------------------------------------------------------
Exception Interface
-------------------------------------------------------------------------------
Hardware Exception Types
-------------------------------------------------------------------------------
Software Trap Types
-------------------------------------------------------------------------------
Signal Delivery
-------------------------------------------------------------------------------
Signal Handler Interface
-------------------------------------------------------------------------------
Chapter 5. Process Initialization
LSB-conforming applications shall use the Process Initialization as defined in
Chapter 3 of the System V Application Binary Interface - Intel386 Architecture
Processor Supplement.
-------------------------------------------------------------------------------
Special Registers
-------------------------------------------------------------------------------
Process Stack (on entry)
-------------------------------------------------------------------------------
Auxilliary Vectors
-------------------------------------------------------------------------------
Environment
-------------------------------------------------------------------------------
Chapter 6. Coding Examples
LSB-conforming applications may implement fundamental operations using the
Coding Examples as defined in Chapter 3 of the System V Application Binary
Interface - Intel386 Architecture Processor Supplement.
-------------------------------------------------------------------------------
Code Model Overview/Architecture Constraints
-------------------------------------------------------------------------------
Position-Independent Fucntion Prologue
-------------------------------------------------------------------------------
Data Objects
-------------------------------------------------------------------------------
Absolute Load & Store
-------------------------------------------------------------------------------
Position Relative Load & Store
-------------------------------------------------------------------------------
Function Calls
-------------------------------------------------------------------------------
Absolute Direct Function Call
-------------------------------------------------------------------------------
Absolute Indirect Function Call
-------------------------------------------------------------------------------
Position-Independent Direct Function Call
-------------------------------------------------------------------------------
Position-Independent Indirect Function Call
-------------------------------------------------------------------------------
Branching
-------------------------------------------------------------------------------
Branch Instruction
-------------------------------------------------------------------------------
Absolute switch() code
-------------------------------------------------------------------------------
Position-Independent switch() code
-------------------------------------------------------------------------------
Chapter 7. C Stack Frame
Variable Argument List
-------------------------------------------------------------------------------
Dynamic Allocation of Stack Space
-------------------------------------------------------------------------------
Chapter 8. Debug Information
The LSB does not currently specify the format of Debug information.
III. Object Format
LSB-conforming implementations shall support an object file , called Executable
and Linking Format (ELF) as defined by the System V Application Binary
Interface, Edition 4.1, the System V Application Binary Interface - DRAFT -
April 29, 1998, System V Application Binary Interface - Intel386 Architecture
Processor Supplement and as supplemented by the Linux Standard Base
Specification and this document.
Table of Contents
9. ELF Header
10. Sections
11. Symbol Table
12. Relocation
-------------------------------------------------------------------------------
Chapter 9. ELF Header
Machine Information
LSB-conforming applications shall use the Machine Information as defined in
Chapter 4 of the System V Application Binary Interface - Intel386 Architecture
Processor Supplement.
-------------------------------------------------------------------------------
File Class
-------------------------------------------------------------------------------
Data Encoding
-------------------------------------------------------------------------------
OS Identification
-------------------------------------------------------------------------------
Processor Identification
-------------------------------------------------------------------------------
Processor Specific Flags
-------------------------------------------------------------------------------
Chapter 10. Sections
-------------------------------------------------------------------------------
Special Sections
The following sections are defined in the System V Application Binary Interface
- Intel386 Architecture Processor Supplement.
Table 10-1.
+-----------------------------------------+
|Name| Type | Attributes |
|----+------------+-----------------------|
|.got|SHT_PROGBITS|SHF_ALLOC+SHF_WRITE |
|----+------------+-----------------------|
|.plt|SHT_PROGBITS|SHF_ALLOC+SHF_EXECINSTR|
+-----------------------------------------+
.got
This section holds the global offset table.
.plt
This section holds the procedure linkage table.
-------------------------------------------------------------------------------
Linux Special Sections
The following Linux IA-32 specific sections are defined here.
Table 10-2.
+--------------------------+
|Name | Type |Attributes |
|-----+--------+-----------|
|.sbss|SHT_NOTE|SHF_WRITE |
+--------------------------+
.sbss
Need a proper description
-------------------------------------------------------------------------------
Section Types
-------------------------------------------------------------------------------
Section Attribute Flags
-------------------------------------------------------------------------------
Special Section Types
-------------------------------------------------------------------------------
Chapter 11. Symbol Table
LSB-conforming applications shall use the Symbol Table as defined in Chapter 4
of the System V Application Binary Interface - Intel386 Architecture Processor
Supplement.
-------------------------------------------------------------------------------
Chapter 12. Relocation
LSB-conforming applications shall use Relocations as defined in Chapter 4 of
the System V Application Binary Interface - Intel386 Architecture Processor
Supplement.
-------------------------------------------------------------------------------
Relocation Types
IV. Program Loading and Dynamic Linking
LSB-conforming implementations shall support the object file information and
system actions that create running programs as specified in the System V
Application Binary Interface, Edition 4.1, the System V Application Binary
Interface - DRAFT - April 29, 1998, System V Application Binary Interface -
Intel386 Architecture Processor Supplement and as supplemented by the Linux
Standard Base Specification and this document.
Table of Contents
13. Program Header
14. Program Loading
15. Dynamic Linking
-------------------------------------------------------------------------------
Chapter 13. Program Header
-------------------------------------------------------------------------------
Types
-------------------------------------------------------------------------------
Flags
-------------------------------------------------------------------------------
Chapter 14. Program Loading
-------------------------------------------------------------------------------
Chapter 15. Dynamic Linking
-------------------------------------------------------------------------------
Program Intepreter/Dynamic Linker
The LSB specifies the Program Interpreter to be
* /lib/ld-lsb.so.1
-------------------------------------------------------------------------------
Dynamic Section
The following dynamic entries are defined in the System V Application Binary
Interface - Intel386 Architecture Processor Supplement.
DT_PLTGOT
On the Intel386 architecture, this entrys d_ptr member gives the address of
the first entry in the global offset table.
-------------------------------------------------------------------------------
Global Offset Table
-------------------------------------------------------------------------------
Shared Object Dependencies
-------------------------------------------------------------------------------
Function Addresses
-------------------------------------------------------------------------------
Procedure Linkage Table
-------------------------------------------------------------------------------
Initialization and Termination Functions
V. Base Libraries
Table of Contents
16. Libraries
-------------------------------------------------------------------------------
Chapter 16. Libraries
An LSB-conforming implementation shall support some base libraries which
provide interfaces for accessing the operating system, processor and other
hardware in the system.
Interfaces that are unique to the IA32 platform are defined here. This section
should be used in conjunction with the corresponding section in the Linux
Standard Base Specification.
-------------------------------------------------------------------------------
Interfaces for libc
Table 16-1. libc Definition
+-------------------+
|Library:|libc |
|--------+----------|
|SONAME: |libc.so.6 |
+-------------------+
The behavior of the interfaces in this library is specified by the following
standards.
Linux Standard Base[1]
-------------------------------------------------------------------------------
Standard Library
Table 16-2. libc - Standard Library Function Interfaces
+---------------------------------------------+
|ioperm(GLIBC_2.0)[1]|iopl(GLIBC_2.0)[1]| | | |
+---------------------------------------------+
-------------------------------------------------------------------------------
Language Support
Table 16-3. libc - Language Support Function Interfaces
+-------------------------------+
|__divdi3(GLIBC_2.0)[1] | | | | |
+-------------------------------+
-------------------------------------------------------------------------------
Data Definitions for libc
-------------------------------------------------------------------------------
Interfaces Definitions for libc
Table of Contents
__divdi3 -- mathematic operation
ioperm -- set port input/output permissions
iopl -- change I/O privilege level
__divdi3
Name
__divdi3 -- mathematic operation
Synopsis
DItype
__divdi3(DItype u, DItype v);
Description
__divdi3() divides two DItypes(unsigned ints).
__divdi3 is not in the source standard; it is only in the binary standard.
ioperm
Name
ioperm -- set port input/output permissions
Synopsis
#include <unistd.h> /* for libc5 */
#include <sys/io.h> /* for glibc */
int ioperm(unsigned long from, unsigned long num, int turn_on);
Description
ioperm sets the port access permission bits for the process for num bytes
starting from port address from to the value turn_on. The use of ioperm
requires root privileges.
Only the first 0x3ff I/O ports can be specified in this manner. For more ports,
the iopl function must be used. Permissions are not inherited on fork, but on
exec they are. This is useful for giving port access permissions to
non-privileged tasks.
Return Value
On success, zero is returned. On error, -1 is returned, and errno is set
appropriately.
Notes
Libc5 treats it as a system call and has a prototype in <unistd.h>. Glibc1 does
not have a prototype. Glibc2 has a prototype both in <sys/io.h> and in <sys/
perm.h>. Avoid the latter, it is available on i386 only.
iopl
Name
iopl -- change I/O privilege level
Synopsis
#include <unistd.h> /* for libc5 */
#include <sys/io.h> /* for glibc */
int iopl(int level);
Description
iopl changes the I/O privilege level of the current process, as specified in
level.
This call is necessary to allow 8514-compatible X servers to run under Linux.
Since these X servers require access to all 65536 I/O ports, the ioperm call is
not sufficient.
In addition to granting unrestricted I/O port access, running at a higher I/O
privilege level also allows the process to disable interrupts. This will
probably crash the system, and is not recommended.
Permissions are inherited by fork and exec.
The I/O privilege level for a normal process is 0.
Return Value
On success, zero is returned. On error, -1 is returned, and errno is set
appropriately.
Errors
EINVAL
level is greater than 3.
EPERM
The current user is not the super-user.
Notes from the Kernel Source
iopl has to be used when you want to access the I/O ports beyond the 0x3ff
range: to get the full 65536 ports bitmapped you'd need 8kB of bitmaps/process,
which is a bit excessive.
Notes
Libc5 treats it as a system call and has a prototype in <unistd.h>. Glibc1 does
not have a prototype. Glibc2 has a prototype both in <sys/io.h> and in <sys/
perm.h>. Avoid the latter, it is available on i386 only.
-------------------------------------------------------------------------------
Interfaces for libm
Table 16-4. libm Definition
+-------------------+
|Library:|libm |
|--------+----------|
|SONAME: |libm.so.6 |
+-------------------+
-------------------------------------------------------------------------------
Data Definitions for libm
-------------------------------------------------------------------------------
Appendix A. Alphabetical Listing of Interfaces
-------------------------------------------------------------------------------
libc
The behaviour of the interfaces in this library is specified by the following
Standards.
Linux Standard Base
Table A-1. libc Function Interfaces
+--------------------------------------------------------------+
|__divdi3(GLIBC_2.0)[1]|ioperm(GLIBC_2.0)[1]|iopl(GLIBC_2.0)[1]|
+--------------------------------------------------------------+
Notes
[1] Linux Standard Base