On Mon, Mar 22, 2021 at 11:55:08AM +1100, Daniel Axtens wrote: > Hi Balbir, > > > Could you highlight the changes from > > https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20170729140901.5887-1-bsingharora@xxxxxxxxx/? > > > > Feel free to use my signed-off-by if you need to and add/update copyright > > headers if appropriate. > > There's not really anything in common any more: > > - ppc32 KASAN landed, so there was already a kasan.h for powerpc, the > explicit memcpy changes, the support for non-instrumented files, > prom_check.sh, etc. all already landed. > > - I locate the shadow region differently and don't resize any virtual > memory areas. > > - The ARCH_DEFINES_KASAN_ZERO_PTE handling changed upstream and our > handling for that is now handled more by patch 3. > > - The outline hook is now an inline function rather than a #define. > > - The init function has been totally rewritten as it's gone from > supporting real mode to not supporting real mode and back. > > - The list of non-instrumented files has grown a lot. > > - There's new stuff: stack walking is now safe, KASAN vmalloc support > means modules are better supported now, ptdump works, and there's > documentation. > > It's been a while now, but I don't think when I started this process 2 > years ago that I directly reused much of your code. So I'm not sure that > a signed-off-by makes sense here? Would a different tag (Originally-by?) > make more sense? > Sure > >> + * The shadow ends before the highest accessible address > >> + * because we don't need a shadow for the shadow. Instead: > >> + * c00e000000000000 << 3 + a80e 0000 0000 0000 000 = c00fc00000000000 > > > > The comment has one extra 0 in a80e.., I did the math and had to use > > the data from the defines :) > > 3 extra 0s, even! Fixed. > > >> +void __init kasan_init(void) > >> +{ > >> + /* > >> + * We want to do the following things: > >> + * 1) Map real memory into the shadow for all physical memblocks > >> + * This takes us from c000... to c008... > >> + * 2) Leave a hole over the shadow of vmalloc space. KASAN_VMALLOC > >> + * will manage this for us. > >> + * This takes us from c008... to c00a... > >> + * 3) Map the 'early shadow'/zero page over iomap and vmemmap space. > >> + * This takes us up to where we start at c00e... > >> + */ > >> + > > > > assuming we have > > #define VMEMMAP_END R_VMEMMAP_END > > and ditto for hash we probably need > > > > BUILD_BUG_ON(VMEMMAP_END + KASAN_SHADOW_OFFSET != KASAN_SHADOW_END); > > Sorry, I'm not sure what this is supposed to be testing? In what > situation would this trigger? > I am bit concerned that we have hard coded (IIR) 0xa80e... in the config, any changes to VMEMMAP_END, KASAN_SHADOW_OFFSET/END should be guarded. Balbir Singh.
