Architecture specific functionality for the ELF loader.

The architecture specific functionality for the Contiki ELF loader has to be implemented for each processor type Contiki runs on. More...

Files
file	elfloader-arch.h
	Header file for the architecture specific parts of the Contiki ELF loader.
file	elfloader-arch-otf.h
	Header file for the architecture specific parts of the Contiki ELF loader.
Functions
void *	elfloader_arch_allocate_ram (int size)
	Allocate RAM for a new module.
void *	elfloader_arch_allocate_rom (int size)
	Allocate program memory for a new module.
void	elfloader_arch_relocate (int fd, unsigned int sectionoffset, char *sectionaddr, struct elf32_rela *rela, char *addr)
	Perform a relocation.
void	elfloader_arch_write_rom (int fd, unsigned short textoff, unsigned int size, char *mem)
	Write to read-only memory (for example the text segment).
int	elfloader_arch_relocate (int input_fd, struct elfloader_output *output, unsigned int sectionoffset, char *sectionaddr, struct elf32_rela *rela, char *addr)
	Perform a relocation.

---

Detailed Description

The architecture specific functionality for the Contiki ELF loader has to be implemented for each processor type Contiki runs on.

Since the ELF format is slightly different for different processor types, the Contiki ELF loader is divided into two parts: the generic ELF loader module (The Contiki ELF loader) and the architecture specific part (this module). The architecture specific part deals with memory allocation, code and data relocation, and writing the relocated ELF code into program memory.

To port the Contiki ELF loader to a new processor type, this module has to be implemented for the new processor type.

---

Function Documentation

void* elfloader_arch_allocate_ram

(

int

size

)

Allocate RAM for a new module.

Parameters:

size	The size of the requested memory.

Returns:

A pointer to the allocated RAM

This function is called from the Contiki ELF loader to allocate RAM for the module to be loaded into.

Definition at line 74 of file elfloader-avr.c.

References mmem_alloc(), mmem_free(), MMEM_PTR, and NULL.

Referenced by elfloader_load().

void* elfloader_arch_allocate_rom

(

int

size

)

Allocate program memory for a new module.

Parameters:

size	The size of the requested memory.

Returns:

A pointer to the allocated program memory

This function is called from the Contiki ELF loader to allocate program memory (typically ROM) for the module to be loaded into.

Definition at line 95 of file elfloader-avr.c.

Referenced by elfloader_load().

int elfloader_arch_relocate	(	int	input_fd,
		struct elfloader_output *	output,
		unsigned int	sectionoffset,
		char *	sectionaddr,
		struct elf32_rela *	rela,
		char *	addr
	)

Perform a relocation.

Parameters:

output	The output object for the segment.
sectionoffset	The file offset at which the relocation can be found.
sectionaddr	The section start address (absolute runtime).
rela	A pointer to an ELF32 rela structure (struct elf32_rela).
addr	The relocated address.

This function is called from the Contiki ELF loader to perform a relocation on a piece of code or data. The relocated address is calculated by the Contiki ELF loader, based on information in the ELF file, and it is the responsibility of this function to patch the executable code. The Contiki ELF loader passes a pointer to an ELF32 rela structure (struct elf32_rela) that contains information about how to patch the code. This information is different from processor to processor.

Definition at line 22 of file elfloader-arm.c.

References cfs_seek(), CFS_SEEK_SET, ELFLOADER_OK, and ELFLOADER_UNHANDLED_RELOC.

void elfloader_arch_relocate	(	int	fd,
		unsigned int	sectionoffset,
		char *	sectionaddr,
		struct elf32_rela *	rela,
		char *	addr
	)

Perform a relocation.

Parameters:

fd	The file descriptor for the ELF file.
sectionoffset	The file offset at which the relocation can be found.
sectionaddr	The section start address (absolute runtime).
rela	A pointer to an ELF32 rela structure (struct elf32_rela).
addr	The relocated address.

This function is called from the Contiki ELF loader to perform a relocation on a piece of code or data. The relocated address is calculated by the Contiki ELF loader, based on information in the ELF file, and it is the responsibility of this function to patch the executable code. The Contiki ELF loader passes a pointer to an ELF32 rela structure (struct elf32_rela) that contains information about how to patch the code. This information is different from processor to processor.

Definition at line 176 of file elfloader-avr.c.

References cfs_seek(), CFS_SEEK_CUR, CFS_SEEK_SET, and ELFLOADER_UNHANDLED_RELOC.

void elfloader_arch_write_rom	(	int	fd,
		unsigned short	textoff,
		unsigned int	size,
		char *	mem
	)

Write to read-only memory (for example the text segment).

Parameters:

fd	The file descriptor for the ELF file.
textoff	Offset of text segment relative start of file.
size	The size of the text segment.
mem	A pointer to the where the text segment should be flashed

This function is called from the Contiki ELF loader to write the program code (text segment) of a loaded module into memory. The function is called when all relocations have been performed.

Definition at line 115 of file elfloader-avr.c.

References cfs_seek(), CFS_SEEK_SET, flash_clear(), flash_done(), flash_setup(), and flash_write().

Referenced by elfloader_load().