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powerpc/pseries/ras: Fix FWNMI_VALID off by one

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[ Upstream commit deb70f7a35a22dffa55b2c3aac71bc6fb0f486ce ]

This was discovered developing qemu fwnmi sreset support. This
off-by-one bug means the last 16 bytes of the rtas area can not
be used for a 16 byte save area.

It's not a serious bug, and QEMU implementation has to retain a
workaround for old kernels, but it's good to tighten it.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Link: https://lore.kernel.org/r/20200508043408.886394-7-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Nicholas Piggin 2020-05-08 14:33:58 +10:00 committed by Sasha Levin
parent 73a5261b3e
commit d0627bd8fc
1 changed files with 3 additions and 2 deletions
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5
arch/powerpc/platforms/pseries/ras.c
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@ -311,10 +311,11 @@ static irqreturn_t ras_error_interrupt(int irq, void *dev_id)
/*
* Some versions of FWNMI place the buffer inside the 4kB page starting at
* 0x7000. Other versions place it inside the rtas buffer. We check both.
* Minimum size of the buffer is 16 bytes.
*/
#define VALID_FWNMI_BUFFER(A) \
((((A) >= 0x7000) && ((A) < 0x7ff0)) || \
(((A) >= rtas.base) && ((A) < (rtas.base + rtas.size - 16))))
((((A) >= 0x7000) && ((A) <= 0x8000 - 16)) || \
(((A) >= rtas.base) && ((A) <= (rtas.base + rtas.size - 16))))
/*
* Get the error information for errors coming through the