Re: [PATCH v2 05/12] powerpc/pseries/ras: FWNMI_VALID off by one
From: Mahesh J Salgaonkar <mahesh@linux.ibm.com>
Date: 2020-03-27 03:55:53
On 2020-03-25 20:34:03 Wed, Nicholas Piggin wrote:
quoted hunk ↗ jump to hunk
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> --- arch/powerpc/platforms/pseries/ras.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c index c74d5e740922..9a37bda47468 100644 --- a/arch/powerpc/platforms/pseries/ras.c +++ b/arch/powerpc/platforms/pseries/ras.c@@ -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.
Acked-by: Mahesh Salgaonkar <mahesh@linux.ibm.com> Thanks, -Mahesh.
*/
#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)
{
--
2.23.0-- Mahesh J Salgaonkar