Hardware and Software Capabilities Section

A SHT_SUNW_cap section identifies the hardware and software capabilities of an object. This section contains an array of the following structures. See sys/link.h.

typedef struct {
        Elf32_Word      c_tag;
        union {
                Elf32_Word      c_val;
                Elf32_Addr      c_ptr;
        } c_un;
} Elf32_Cap;

typedef struct {
        Elf64_Xword     c_tag;
        union {
                Elf64_Xword     c_val;
                Elf64_Addr      c_ptr;
        } c_un;
} Elf64_Cap;

For each object with this type, c_tag controls the interpretation of c_un.

c_val

These objects represent integer values with various interpretations.

c_ptr

These objects represent program virtual addresses.

The following capabilities tags exist.

Table 7–12 ELF Capability Array Tags

Name	Value	c_un
CA_SUNW_NULL	0	Ignored
CA_SUNW_HW_1	1	c_val
CA_SUNW_SF_1	2	c_val

CA_SUNW_NULL

Marks the end of the capabilities array.

CA_SUNW_HW_1

Indicates hardware capability values. The c_val element contains a value that represents the associated hardware capabilities. On SPARC platforms, hardware capabilities are defined in sys/auxv_SPARC.h. On x86 platforms, hardware capabilities are defined in sys/auxv_386.h.

CA_SUNW_SF_1

Indicates software capability values. The c_val element contains a value that represents the associated software capabilities that are defined in sys/elf.h.

Relocatable objects can contain a capabilities section. The link-editor combines any capabilities sections from multiple input relocatable objects into a single capabilities section. The link-editor also allows capabilities to be defined at the time an object is built. See Identifying Hardware and Software Capabilities.

A dynamic object that contains a capabilities section that contains hardware capabilities information, has a PT_SUNWCAP program header associated to the section. This program header allows the runtime linker to validate the object against the hardware capabilities that are available to the process.

Dynamic objects that exploit different hardware capabilities can provide a flexible runtime environment using filters. See Hardware Capability Specific Shared Objects.