| Message ID | 80432f71194d7ee75b2f5043ecf1501cf1cca1f3.1566196646.git.christophe.leroy@c-s.fr (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 415480dce2ef03bb8335deebd2f402f475443ce0 |
| Headers | show |
| Series | powerpc/603: fix handling of the DIRTY flag | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch next (c9633332103e55bc73d80d07ead28b95a22a85a3) |
| snowpatch_ozlabs/build-ppc64le | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64be | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64e | success | Build succeeded |
| snowpatch_ozlabs/build-pmac32 | success | Build succeeded |
| snowpatch_ozlabs/checkpatch | warning | total: 0 errors, 1 warnings, 0 checks, 11 lines checked |
On Mon, 2019-08-19 at 06:40:25 UTC, Christophe Leroy wrote: > If a page is already mapped RW without the DIRTY flag, the DIRTY > flag is never set and a TLB store miss exception is taken forever. > > This is easily reproduced with the following app: > > void main(void) > { > volatile char *ptr = mmap(0, 4096, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); > > *ptr = *ptr; > } > > When DIRTY flag is not set, bail out of TLB miss handler and take > a minor page fault which will set the DIRTY flag. > > Fixes: f8b58c64eaef ("powerpc/603: let's handle PAGE_DIRTY directly") > Cc: stable@vger.kernel.org > Reported-by: Doug Crawford <doug.crawford@intelight-its.com> > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/415480dce2ef03bb8335deebd2f402f475443ce0 cheers
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S index f255e22184b4..534dd2718795 100644 --- a/arch/powerpc/kernel/head_32.S +++ b/arch/powerpc/kernel/head_32.S @@ -557,9 +557,9 @@ DataStoreTLBMiss: cmplw 0,r1,r3 mfspr r2, SPRN_SPRG_PGDIR #ifdef CONFIG_SWAP - li r1, _PAGE_RW | _PAGE_PRESENT | _PAGE_ACCESSED + li r1, _PAGE_RW | _PAGE_DIRTY | _PAGE_PRESENT | _PAGE_ACCESSED #else - li r1, _PAGE_RW | _PAGE_PRESENT + li r1, _PAGE_RW | _PAGE_DIRTY | _PAGE_PRESENT #endif bge- 112f lis r2, (swapper_pg_dir - PAGE_OFFSET)@ha /* if kernel address, use */
If a page is already mapped RW without the DIRTY flag, the DIRTY flag is never set and a TLB store miss exception is taken forever. This is easily reproduced with the following app: void main(void) { volatile char *ptr = mmap(0, 4096, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); *ptr = *ptr; } When DIRTY flag is not set, bail out of TLB miss handler and take a minor page fault which will set the DIRTY flag. Fixes: f8b58c64eaef ("powerpc/603: let's handle PAGE_DIRTY directly") Cc: stable@vger.kernel.org Reported-by: Doug Crawford <doug.crawford@intelight-its.com> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/kernel/head_32.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)