how to make loadable kernel module on solaris? no linux

Question

1. how to create loadable kernel module on solaris 11?

• simple loadable kernel module (hello world).
• I searched, but only showed how to create a Linux kernel module.
• in linux, header linux/kernel.h, but not included header on solaris

2. how to compile loadable kernel module on solaris 11?

• gcc -D_KERNEL -m64 -c cpluscplus.cpp
• Is it appropriate to compile as above?
• 64bit, x86

Answer 1

Here's the minimal hello world kernel module I can come up with:

#include <sys/modctl.h>
#include <sys/cmn_err.h>

/*
 * Module linkage information for the kernel.
 */
static struct modlmisc modlmisc = {
        &mod_miscops, "test module"
};

static struct modlinkage modlinkage = {
        MODREV_1, (void *)&modlmisc, NULL
};


int
_init(void)
{
        return (mod_install(&modlinkage));
}

int
_fini(void)
{
        return (mod_remove(&modlinkage));
}

int
_info(struct modinfo *modinfop)
{
        cmn_err(CE_NOTE, "hello kernel");
        return (mod_info(&modlinkage, modinfop));
}

Compiling this as 64-bit binary with Oracle Developer Studio 12.6 and the Solaris linker like so:

cc -D_KERNEL -I include -m64 -c foomod.c
ld -64 -z type=kmod -znodefs -o foomod foomod.o

For GCC you will likely need a distinct set of options.

Then load it with:

modload ./foomod

This will complain about signature verification. This is innocuous unless you are running the system with Verified Boot enabled.

Check that module is loaded:

# modinfo -i foomod
ID  LOADADDR         SIZE   INFO REV NAMEDESC
312 fffffffff7a8ddc0 268    --   1   foomod (test module)
# dmesg | tail -1
Mar 16 12:22:57 ST091 foomod: [ID 548715 kern.notice] NOTICE: hello kernel

This works on Solaris 11.4 SRU 33 running on x86 machine (VirtualBox instance in fact).