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Date: Thu, 12 Jan 2012 13:20:48 +0530
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From: "Jayachandran C." <c.jayachandran@gmail.com>
To: Oleksandr Tymoshenko <gonzo@freebsd.org>
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Cc: "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org>,
	Alan Cox <alc@rice.edu>
Subject: Re: MIPS64 modules
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On Thu, Jan 12, 2012 at 4:51 AM, Oleksandr Tymoshenko <gonzo@freebsd.org> w=
rote:
> =A0 =A0Modules on MIPS use the same interface as AMD64 modules:
> sys/kern/link_elf_obj.c. It works for MIPS32 but there is a problem
> with MIPS64. sys/kern/link_elf_obj.c calls vm_map_find that uses
> KERNBASE as a map base. As I told - it works for mips32 because
> KERNBASE for mips32 is located before actual virtual memory area
> (KERNBASE points to directly-mapped KSEG0 segment). But for MIPS64
> it's not the case - KERNBASE points to the very end of address space
> and vm_map_find fails.
>
> Using VM_MIN_KERNEL_ADDRESS fixes this problem. So the question is -
> what should I do? Add #ifdef to link_elf_obj.c as in kmem_init in
> vm/vm_kern.c or change KERNBASE to VM_MIN_KERNEL_ADDRESS?

This is probably the right fix for both 32 and 64-bit mips. Using a
KSEG0 address as argument for vm_map_find is not correct as the kernel
map does not include that region for mips.

This reminds me of another issue I had seen in kern/link_elf.c, the
value of linker_kernel_file->address is also set to KERNBASE, but this
really should be KERNLOADADDR (used in our conf files) for mips.


JC.