Re: [PATCH v4] powerpc: 64K page support for kexec

[Milton Miller <miltonm@bga.com>]

On Apr 27, 2007, at 11:22 AM, Luke Browni+	/*
> +	 * FIXME, the code below works for 16M, 64K, and 4K pages as these
> +	 * fall under the p<=23 rules for calculating the virtual address.
> +	 * In the case of 16M pages, an extra bit is stolen from the AVPN
> +	 * field to achieve the requisite 24 bits.
> +	 *
> +	 * You can use kexec -l to debug new page support!
> +	 */
> +	BUG_ON(hpte_v & 0x4000000000000000UL && !panic);   /* 1T segment */
> +	BUG_ON(size == MMU_PAGE_16G && !panic);
> +	BUG_ON(size == MMU_PAGE_64K_AP && !panic);
> +

I see I've achived my nefarious goal of making these bugs never happen.

(panic is a function, so you are checking that the staticly linked
non-weak function is available.   If you want to check on when
if its a panic kdump or not, you need to decode the flag and pass
it to kexec_sequence, pass it back here, and update all platforms
for the new parameter).

But I still say the check while clearing the table is too late,
it should be a debug scan before clearing any mappings.

milton