Hi Mark, On 14/12/16 11:37, Mark Rutland wrote: > On Wed, Dec 14, 2016 at 11:16:17AM +0000, James Morse wrote: >> On 14/12/16 10:12, Pratyush Anand wrote: >>> On Wednesday 14 December 2016 03:08 PM, Pratyush Anand wrote: >>>>> I would go as far as to generate the page tables at 'kexec -l' time, >>>>> and only if >>>> >>>> Ok..So you mean that I create a new section which will have page table >>>> entries mapping physicalmemory represented by remaining section, and >>>> then purgatory can just enable mmu with page table from that section, >>>> right? Seems doable. can do that. >>> >>> I see a problem here. If we create page table as a new segment then, how can we >>> verify in purgatory that sha for page table is correct? We need page table >>> before sha verification start,and we can not rely the page table created by >>> first kernel until it's sha is verified. So a chicken-egg problem. >> >> There is more than one of those! What happens if your sha256 calculation code is >> corrupted? You have to run it before you know. The same goes for all the >> purgatory code. >> >> This is why I think its better to do this in the kernel before we exit to >> purgatory, but obviously that doesn't work for kdump. > > I see in an earlier message that the need for sha256 was being discussed > in another thread. Do either of you happen to have a pointer to that. https://www.spinics.net/lists/arm-kernel/msg544472.html Thanks, James
