Messages in this thread |  | | | From | coder@kanga ... | | Subject | Re: Reserving a (large) memory block | | Date | Fri, 01 Sep 2000 19:10:39 -0700 |
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On Thu, 31 Aug 2000 17:12:03 +0100 (BST) Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
>> Now the device behaves just like memory to the BIOS during POST >> etc, and is in fact, exactly memory if no device drivers are >> loaded. If a device driver is loaded and it detects one or more >> of these devices then they and their memory ranges become >> obviously special. Now, we can detect the devices and where >> their address ranges are via the SMBUS and some careful probing >> so we know what we are trying to grab. The problem is just >> telling the rest of the kernel that in a clean VM&heap-happy >> manner.
> Basically your base driver will have to do it at boot up > time. Once that memory is allocated to someone you may not be able > to move the memory and borrow the pages.
Aye, that's what we're doing ATM. We find the board and its size, and then go and edit mem_map and mark it reserved and uncacheable. It doesn't seem the most graceful approach and I was hoping for something cleaner (tho that looks like 2.4 per Ingo's comments which I still have to look into).
> You don't neccessarily need the whole driver in the main kernel > but you will need to grab the devices, reserve the memory pages in > question and mark them as reserved before Linux gets going > properly. Your actual users of these pages can then be dynamically > loaded.
Yeah, that's what I'm looking at right now: how early I have to get in to be safe.
-- J C Lawrence Home: claw@kanga.nu ---------(*) Work: claw@nuron.com http://www.kanga.nu/~claw/ Keys etc: finger claw@kanga.nu --=| A man is as sane as he is dangerous to his environment |=-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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