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powerpc/64s: Default l1d_size to 64K in RFI fallback flush

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If there is no d-cache-size property in the device tree, l1d_size could
be zero. We don't actually expect that to happen, it's only been seen
on mambo (simulator) in some configurations.

A zero-size l1d_size leads to the loop in the asm wrapping around to
2^64-1, and then walking off the end of the fallback area and
eventually causing a page fault which is fatal.

Just default to 64K which is correct on some CPUs, and sane enough to
not cause a crash on others.

Fixes: aa8a5e0062ac9 ('powerpc/64s: Add support for RFI flush of L1-D cache')
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
[mpe: Rewrite comment and change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Madhavan Srinivasan 2018-01-18 00:33:36 +05:30 committed by Michael Ellerman
parent b8858581fe
commit 9dfbf78e41
1 changed files with 11 additions and 0 deletions
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11
arch/powerpc/kernel/setup_64.c
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@ -890,6 +890,17 @@ static void __ref init_fallback_flush(void)
return;
l1d_size = ppc64_caches.l1d.size;
/*
* If there is no d-cache-size property in the device tree, l1d_size
* could be zero. That leads to the loop in the asm wrapping around to
* 2^64-1, and then walking off the end of the fallback area and
* eventually causing a page fault which is fatal. Just default to
* something vaguely sane.
*/
if (!l1d_size)
l1d_size = (64 * 1024);
limit = min(ppc64_bolted_size(), ppc64_rma_size);
/*