1.1. General

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.

These specifications are composed of two basic parts: A common specification ("LSB-generic") describing those parts of the interface that remain constant across all implementations of the LSB, and an architecture-specific specification ("LSB-arch") describing the parts of the interface that vary by processor architecture. Together, the LSB-generic 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.

The LSB-generic document shall be used in conjunction with an architecture-specific supplement. Whenever a section of the LSB-generic specification shall be supplemented by architecture-specific information, the LSB-generic document includes a reference to the architecture supplement. Architecture supplements may also contain additional information that is not referenced in the LSB-generic document.

The LSB contains both a set of Application Program Interfaces (APIs) and Application Binary Interfaces (ABIs). APIs may appear in the source code of portable applications, while the compiled binary of that application may use the larger set of ABIs. A conforming implementation shall provide all of the ABIs listed here. The compilation system may replace (e.g. by macro definition) certain APIs with calls to one or more of the underlying binary interfaces, and may insert calls to binary interfaces as needed.

The LSB is primarily a binary interface definition. Not all of the source level APIs available to applications may be contained in this specification.

1.2. Module Specific Scope

This is the Itanium architecture specific Core module of the Linux Standards Base (LSB). This module supplements the generic LSB Core module with those interfaces that differ between architectures.

Interfaces described in this module are mandatory except where explicitly listed otherwise. Core interfaces may be supplemented by other modules; all modules are built upon the core.

3.1. Relevant Libraries

The libraries listed in Table 3-1 shall be available on IA64 Linux Standard Base systems, with the specified runtime names. These names override or supplement the names specified in the generic LSB specification. The specified program interpreter, referred to as proginterp in this table, shall be used to load the shared libraries specified by DT_NEEDED entries at run time.

These libraries will be in an implementation-defined directory which the dynamic linker shall search by default.

3.2. LSB Implementation Conformance

A conforming implementation shall satisfy the following requirements:

• The implementation shall implement fully the architecture described in the hardware manual for the target processor architecture.

• The implementation shall be capable of executing compiled applications having the format and using the system interfaces described in this document.

• 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 this document.

• The map of virtual memory provided by the implementation shall conform to the requirements of this document.

• 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.

• The implementation shall provide all of the mandatory interfaces in their entirety.

• 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.

• The implementation shall provide all files and utilities specified as part of this document in the format 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.

• 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.

• 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.

3.3. LSB Application Conformance

A conforming application shall satisfy the following requirements:

• Its executable files are either shell scripts or object files in the format defined for the Object File Format system interface.

• Its object files participate in dynamic linking as defined in the Program Loading and Linking System interface.

• It employs only the instructions, traps, and other low-level facilities defined in the Low-Level System interface as being for use by applications.

• 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.

• It does not use any interface or data format that is not required to be provided by a conforming implementation, unless:

  • If such an interface or data format is supplied by another application through direct invocation of that application during execution, that application is in turn an LSB conforming application.

  • The use of that interface or data format, as well as its source, is identified in the documentation of the application.

• It shall not use any values for a named interface that are reserved for vendor extensions.

1.1. Processor Architecture

The Itanium™ Architecture is specified by the following documents

• Itanium ™ Architecture Software Developer's Manual Volume 1

• Itanium ™ Architecture Software Developer's Manual Volume 2

• Itanium ™ Architecture Software Developer's Manual Volume 3

• Itanium ™ Architecture Software Developer's Manual Volume 4

• Itanium ™ Software Conventions and Runtime Guide

• Intel® Itanium ™ Processor-specific Application Binary Interface

Only the features of the Itanium™ 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.

Only instructions which do not require elevated privileges may be used.

Applications may not make system calls directly. The interfaces in the C library must be used instead.

There are some features of the Itanium™ processor architecture that need not be supported by a conforming implementation. These are described in this chapter. A conforming application shall not rely on these features.

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 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.

This specification describes only LP64 (i.e. 32-bit integers, 64-bit longs and pointers) based implementations. Implementations may also provide ILP32 (32-bit integers, longs, and pointers), but conforming applications shall not rely on support for ILP32. See section 1.2 of the Intel® Itanium ™ Processor-specific Application Binary Interface for further information.

1.2. Data Representation

See Itanium ™ Software Conventions and Runtime Guide Chapter 4.

Within this specification, the term byte refers to an 8-bit object, the term halfword refers to a 16-bit object, the term word refers to a 32-bit object, the term doubleword refers to a 64-bit object, and the term quadword refers to a 128-bit object. Although the Itanium™ architecture also supports 120-bit addressable objects, this specification does not require LSB-conforming implementations to provide support for these objects.

    struct {
        char c;
    }
   

    struct {
        char  c;
        char  d;
        short s;
        int   i;
        long  l;
    }
   

    struct {
        char  c;
        long  l;
        int   i;
        short s;
    }
   

signed char
char
unsigned char
     

-2w-1 to 2w-1-1
0 to 2w-1
0 to 2w-1
     

signed short
short
unsigned short
     

-2w-1 to 2w-1-1
0 to 2w-1
0 to 2w-1
     

signed int
int
unsigned int
     

-2w-1 to 2w-1-1
0 to 2w-1
0 to 2w-1
     

signed long
long
unsigned long
     

-2w-1 to 2w-1-1
0 to 2w-1
0 to 2w-1
     

2.1. CPU Registers

The CPU general and other registers are as defined in the Itanium ™ Architecture Software Developer's Manual Volume 1 Section 3.1.

2.2. Floating Point Registers

The floating point registers are as defined in the Itanium ™ Architecture Software Developer's Manual Volume 1 Section 3.1.

2.3. Stack Frame

The stackframe layout is as described in the Itanium ™ Software Conventions and Runtime Guide Chapter 8.4.

2.4. Arguments

The procedure argument passing mechanism is as described in the Itanium ™ Software Conventions and Runtime Guide Chapter 8.5.

2.5. Return Values

See Itanium ™ Software Conventions and Runtime Guide Chapter 8.6.

3.1. Processor Execution Mode

Applications must assume that they will execute in the least privileged user mode (i.e. level 3). Other privilege levels are reserved for the Operating System.

3.2. Exception Interface

See Intel® Itanium ™ Processor-specific Application Binary Interface, section 3.3.1.

3.3. Signal Delivery

See Intel® Itanium ™ Processor-specific Application Binary Interface, section 3.3.2.

4.1. Special Registers

Intel® Itanium ™ Processor-specific Application Binary Interface, section 3.3.5, defines required register initializations for process startup.

4.2. Process Stack (on entry)

As defined in Intel® Itanium ™ Processor-specific Application Binary Interface, section 3.3.5, the return pointer register (rp) shall contain a valid return address, such that if the application program returns from the main entry routine, the implementation shall cause the application to exit normally, using the returned value as the exit status. Further, the unwind information for this "bottom of stack" routine in the implementation shall provide a mechanism for recognizing the bottom of the stack during a stack unwind.

4.3. Auxiliary Vector

The auxiliary vector conveys information from the operating system to the application. Only the terminating null auxiliary vector entry is required, but if any other entries are present, they shall be interpreted as follows. This vector is an array of the following structures.

typedef struct
{
  long int a_type;              /* Entry type */
  union
    {
      long int a_val;           /* Integer value */
      void *a_ptr;              /* Pointer value */
      void (*a_fcn) (void);     /* Function pointer value */
    } a_un;
} auxv_t;

The application shall interpret the a_un value according to the a_type. Other auxiliary vector types are reserved.

The a_type field shall contain one of the following values:

4.4. Environment

Although a pointer to the environment vector should be available as a third argument to the main() entry point, conforming applications should use getenv() to access the environment. (See ISO POSIX (2003), Section exec()).

5.1. Code Model Overview/Architecture Constraints

As defined in Intel® Itanium ™ Processor-specific Application Binary Interface, relocatable files, executable files, and shared object files that are supplied as part of an application must use Position Independent Code, as described in Itanium ™ Software Conventions and Runtime Guide, Chapter 12.

5.2. Position-Independent Function Prologue

See Itanium ™ Software Conventions and Runtime Guide, Chapter 8.4.

5.3. Data Objects

See Intel® Itanium ™ Processor-specific Application Binary Interface, Chapter 5.3.4, and Itanium ™ Software Conventions and Runtime Guide, Chapter 12.3.

5.4. Function Calls

See Itanium ™ Software Conventions and Runtime Guide, Chapter 8.4.

Four types of procedure call are defined in Itanium ™ Software Conventions and Runtime Guide, Chapter 8.3. Although special calling conventions are permitted, provided that the compiler and runtime library agree on these conventions, none are defined for this standard. Consequently, no application shall depend on a type of procedure call other than Direct Calls, Direct Dynamically Linked Calls, or Indirect Calls, as defined in Itanium ™ Software Conventions and Runtime Guide, Chapter 8.3.

5.5. Branching

Branching is described in Itanium ™ Architecture Software Developer's Manual Volume 4, Chapter 4.5.

6.1. Variable Argument List

See Itanium ™ Software Conventions and Runtime Guide, Chapter 8.5.2, and 8.5.4.

6.2. Dynamic Allocation of Stack Space

The C library alloca() function should be used to dynamically allocate stack space.

8.1. Machine Information

LSB-conforming applications shall use the Machine Information as defined in Intel® Itanium ™ Processor-specific Application Binary Interface, Chapter 4. Implementations shall support the LP64 model. It is unspecified whether or not the ILP32 model shall also be supported.

9.1. Special Sections

The following sections are defined in the Intel® Itanium ™ Processor-specific Application Binary Interface.

9.2. Linux Special Sections

The following Linux IA-64 specific sections are defined here.

9.3. Section Types

Section Types are described in the Intel® Itanium ™ Processor-specific Application Binary Interface, Chapter 4.2. LSB conforming implementations are not required to use any sections in the range from SHT_IA_64_LOPSREG to SHT_IA_64_HIPSREG. Additionally, LSB conforming implementations are not required to support the SHT_IA_64_PRIORITY_INIT section, beyond the gABI requirements for the handling of unrecognized section types, linking them into a contiguous section in the object file created by the static linker.

9.4. Section Attribute Flags

See Intel® Itanium ™ Processor-specific Application Binary Interface, Chapter 4.2.2.

9.5. Special Section Types

See Intel® Itanium ™ Processor-specific Application Binary Interface, Chapter 4.2.3.

11.1. Relocation Types

See Intel® Itanium ™ Processor-specific Application Binary Interface, Chapter 4.3.

12.1. Types

See Intel® Itanium ™ Processor-specific Application Binary Interface, Chapter 5.1.

12.2. Flags

See Intel® Itanium ™ Processor-specific Application Binary Interface, Chapter 5.1.

14.1. Dynamic Entries

14.2. Global Offset Table

See Intel® Itanium ™ Processor-specific Application Binary Interface, Chapter 5.3.4.

14.3. Shared Object Dependencies

See Intel® Itanium ™ Processor-specific Application Binary Interface, Chapter 5.3.3.

14.4. Function Addresses

See Intel® Itanium ™ Processor-specific Application Binary Interface, Chapter 5.3.5.

14.5. Procedure Linkage Table

See Intel® Itanium ™ Processor-specific Application Binary Interface, Chapter 5.3.6.

14.6. Initialization and Termination Functions

See Intel® Itanium ™ Processor-specific Application Binary Interface, Chapter 5.3.7.

1.1. Program Interpreter/Dynamic Linker

The LSB specifies the Program Interpreter to be /lib/ld-lsb-ia64.so.3.

1.2. Interfaces for libc

Table 1-1 defines the library name and shared object name for the libc library

The behavior of the interfaces in this library is specified by the following specifications: