Messages in this thread | | | Subject | Re: [PATCH v2] powerpc/32s: fix BATs setting with CONFIG_STRICT_KERNEL_RWX | From | christophe leroy <> | Date | Wed, 1 May 2019 19:22:06 +0200 |
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Le 01/05/2019 à 02:55, Michael Ellerman a écrit : > Christophe Leroy <christophe.leroy@c-s.fr> writes: >> Serge reported some crashes with CONFIG_STRICT_KERNEL_RWX enabled >> on a book3s32 machine. >> >> Analysis shows two issues: >> - BATs addresses and sizes are not properly aligned. >> - There is a gap between the last address covered by BATs and the >> first address covered by pages. >> >> Memory mapped with DBATs: >> 0: 0xc0000000-0xc07fffff 0x00000000 Kernel RO coherent >> 1: 0xc0800000-0xc0bfffff 0x00800000 Kernel RO coherent >> 2: 0xc0c00000-0xc13fffff 0x00c00000 Kernel RW coherent >> 3: 0xc1400000-0xc23fffff 0x01400000 Kernel RW coherent >> 4: 0xc2400000-0xc43fffff 0x02400000 Kernel RW coherent >> 5: 0xc4400000-0xc83fffff 0x04400000 Kernel RW coherent >> 6: 0xc8400000-0xd03fffff 0x08400000 Kernel RW coherent >> 7: 0xd0400000-0xe03fffff 0x10400000 Kernel RW coherent >> >> Memory mapped with pages: >> 0xe1000000-0xefffffff 0x21000000 240M rw present dirty accessed >> >> This patch fixes both issues. With the patch, we get the following >> which is as expected: >> >> Memory mapped with DBATs: >> 0: 0xc0000000-0xc07fffff 0x00000000 Kernel RO coherent >> 1: 0xc0800000-0xc0bfffff 0x00800000 Kernel RO coherent >> 2: 0xc0c00000-0xc0ffffff 0x00c00000 Kernel RW coherent >> 3: 0xc1000000-0xc1ffffff 0x01000000 Kernel RW coherent >> 4: 0xc2000000-0xc3ffffff 0x02000000 Kernel RW coherent >> 5: 0xc4000000-0xc7ffffff 0x04000000 Kernel RW coherent >> 6: 0xc8000000-0xcfffffff 0x08000000 Kernel RW coherent >> 7: 0xd0000000-0xdfffffff 0x10000000 Kernel RW coherent >> >> Memory mapped with pages: >> 0xe0000000-0xefffffff 0x20000000 256M rw present dirty accessed >> >> Reported-by: Serge Belyshev <belyshev@depni.sinp.msu.ru> >> Fixes: 63b2bc619565 ("powerpc/mm/32s: Use BATs for STRICT_KERNEL_RWX") >> Cc: stable@vger.kernel.org > > I could probably still get this into v5.1 if you're confident it's a > good fix.
If possible it would be great.
Yes I'm confident it is a good fix: - The fix has no impact on the configurations I tested originally (they were lacking a trailing area not mapped with BATs and the boundarie between RW and RO was a power of 2 so ffs() returned the same as lfs()) - The fix was tested by myself on QEMU. - The fix was tested by Serge. - The fix was acked by Segher. - The fix make sense (ie ffs() is the good one, fls() was definitly wrong)
Christophe
> > cheers >
--- L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast. https://www.avast.com/antivirus
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