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Commit 1a588c7e authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Greg Kroah-Hartman
Browse files

powerpc/pseries/ras: Fix FWNMI_VALID off by one 



[ 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: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Acked-by: default avatarMahesh Salgaonkar <mahesh@linux.ibm.com>
Link: https://lore.kernel.org/r/20200508043408.886394-7-npiggin@gmail.com


Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 8240829f

arch/powerpc/platforms/pseries/ras.c

+3 −2
Original line number Diff line number Diff line
@@ -395,10 +395,11 @@ 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))))



static inline struct rtas_error_log *fwnmi_get_errlog(void)

{