[PATCH 4.9 173/222] powerpc/pseries: Fix how we iterate over the DTL entries

From: Greg Kroah-Hartman
Date: Fri Nov 22 2019 - 05:46:56 EST

From: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>

[ Upstream commit 9258227e9dd1da8feddb07ad9702845546a581c9 ]

When CONFIG_VIRT_CPU_ACCOUNTING_NATIVE is not set, we look up dtl_idx in
the lppaca to determine the number of entries in the buffer. Since
lppaca is in big endian, we need to do an endian conversion before using
this in our calculation to determine the number of entries in the
buffer. Without this, we do not iterate over the existing entries in the
DTL buffer properly.

Fixes: 7c105b63bd98 ("powerpc: Add CONFIG_CPU_LITTLE_ENDIAN kernel config option.")
Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
arch/powerpc/platforms/pseries/dtl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/dtl.c b/arch/powerpc/platforms/pseries/dtl.c
index 37de83c5ef172..7a4d172c93765 100644
--- a/arch/powerpc/platforms/pseries/dtl.c
+++ b/arch/powerpc/platforms/pseries/dtl.c
@@ -185,7 +185,7 @@ static void dtl_stop(struct dtl *dtl)

static u64 dtl_current_index(struct dtl *dtl)
- return lppaca_of(dtl->cpu).dtl_idx;
+ return be64_to_cpu(lppaca_of(dtl->cpu).dtl_idx);