@rickgaiser, I’m glad you found it inspirational! I made an effort to put as much logic as possible into the tooling, so that writing the actual IOP modules becomes effortless. This means that a module function declaration such as

Line 17 in a5d2360

id_(0) int printk(const char *fmt, ...) __attribute__((format(printf, 1, 2)));

serves quadruple-duty: the id_ macro is used to produce both import and export directives, automatically, and the rest of the declaration is used by the C compiler as usual. The standard IOP modules are declared in the same way, for example sifcmd. The fourth duty is to display exports and imports, symbolically, in the iopmod-info tool, used to inspect IRX module files.

I wrote a small C language lexer in tool/lexc.c, which is actually complete, and a simple ELF parser in tool/elf.c for the tooling.

The GNU linker option --gc-sections ensures that only the relevant pieces of code are linked into the final module, which saves space without any manual effort. There is also a special automatic _module_init

iopmod/include/iopmod/mod.h

Lines 30 to 42 in a5d2360

    
           enum module_init_status _module_init(int argc, char *argv[]) 
        
           { 
        
           	int err = loadcore_register_library(_module_export); 
        
           	if (err < 0) 
        
           		return MODULE_EXIT; 
        
           	enum module_init_status status = _module_start(argc, argv); 
        
           	if (status == MODULE_EXIT) 
        
           		loadcore_release_library(_module_export); 
        
           	return status; 
        
           }

which sets up the exports automatically, so modules don’t do that themselves. It then calls _module_start, which is declared with module_init in the module, as in for example

iopmod/module/irqrelay.c

Line 305 in a5d2360

module_init(irqrelay_init);

Modules that don’t initialise anything don’t need to declare a module_init at all, so that simplification works too. The module/printk.c module for example only exports a function that prints in the Linux kernel log, similar to the kernel’s own printk.

The module/irqrelay.c module on the other hand sets up an RPC service, for relaying interrupts, so it needs the initialisation, but since it doesn’t export any functions its header file

iopmod/include/iopmod/module/irqrelay.h

Lines 1 to 3 in a5d2360

    
           // SPDX-License-Identifier: GPL-2.0 
        
           MODULE_ID(irqrelay, 0x0100);

is correspondingly simple, having only to declare the identification and the version of the module.

	enum module_init_status _module_init(int argc, char *argv[])
	{
	int err = loadcore_register_library(_module_export);
	if (err < 0)
	return MODULE_EXIT;

	enum module_init_status status = _module_start(argc, argv);

	if (status == MODULE_EXIT)
	loadcore_release_library(_module_export);

	return status;
	}

	// SPDX-License-Identifier: GPL-2.0

	MODULE_ID(irqrelay, 0x0100);

Modules break with compiler optimisation greater than -O0 #1

Description

Metadata

Metadata

Assignees

Labels

Projects

Milestone

Relationships

Development

Issue actions