Messages in this thread | ![/](/images/icornerl.gif) | | From | Michael Ellerman <> | Subject | Re: [PATCH] powerpc/32: disable KASAN with pages bigger than 16k | Date | Tue, 02 Jun 2020 20:25:48 +1000 |
| |
Christophe Leroy <christophe.leroy@csgroup.eu> writes: > Le 28/05/2020 à 12:17, Christophe Leroy a écrit : >> Mapping of early shadow area is implemented by using a single static >> page table having all entries pointing to the same early shadow page. >> The shadow area must therefore occupy full PGD entries. >> >> The shadow area has a size of 128Mbytes starting at 0xf8000000. >> With 4k pages, a PGD entry is 4Mbytes >> With 16k pages, a PGD entry is 64Mbytes >> With 64k pages, a PGD entry is 256Mbytes which is too big. > > That's for 32k pages that a PGD is 256Mbytes. > > With 64k pages, a PGD entry is 1Gbytes which is too big. > > Michael, can you fix the commit log ?
Yes.
powerpc/32: Disable KASAN with pages bigger than 16k
Mapping of early shadow area is implemented by using a single static page table having all entries pointing to the same early shadow page. The shadow area must therefore occupy full PGD entries.
The shadow area has a size of 128MB starting at 0xf8000000. With 4k pages, a PGD entry is 4MB With 16k pages, a PGD entry is 64MB With 64k pages, a PGD entry is 1GB which is too big. Until we rework the early shadow mapping, disable KASAN when the page size is too big.
Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support") Cc: stable@vger.kernel.org # v5.2+ Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/7195fcde7314ccbf7a081b356084a69d421b10d4.1590660977.git.christophe.leroy@csgroup.eu
cheers
| ![\](/images/icornerr.gif) |