From 6a6d71ed56cb4339412982ceef36c610d8e3217d Mon Sep 17 00:00:00 2001
From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
Date: Fri, 8 Mar 2019 07:36:30 +0530
Subject: [PATCH] pseries/energy: Use OF accessor function to read
ibm,drc-indexes
References: bsc#1129080
Patch-mainline: submitted https://patchwork.ozlabs.org/patch/1053567/
In cpu_to_drc_index() we currently use of_read_property() to obtain
the pointer to the array corresponding to the property
"ibm,drc-indexes". The elements of this array are of type __be32, but
are accessed without any conversion to the host-endianness, which is
buggy on a Little Endian OS.
Fix this by using of_property_read_u32_index() accessor function to
safely read the elements of the array.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
.../platforms/pseries/pseries_energy.c | 28 +++++++++++--------
1 file changed, 17 insertions(+), 11 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/pseries_energy.c b/arch/powerpc/platforms/pseries/pseries_energy.c
index 164a13d3998a..5d99a89b1047 100644
--- a/arch/powerpc/platforms/pseries/pseries_energy.c
+++ b/arch/powerpc/platforms/pseries/pseries_energy.c
@@ -38,27 +38,33 @@ static int sysfs_entries;
static u32 cpu_to_drc_index(int cpu)
{
struct device_node *dn = NULL;
- const int *indexes;
+ u32 nr_drc_indexes, i_drc_index;
int i;
- int rc = 1;
+ int rc;
u32 ret = 0;
dn = of_find_node_by_path("/cpus");
if (dn == NULL)
goto err;
- indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
- if (indexes == NULL)
- goto err_of_node_put;
+
/* Convert logical cpu number to core number */
i = cpu_core_index_of_thread(cpu);
+
/*
- * The first element indexes[0] is the number of drc_indexes
- * returned in the list. Hence i+1 will get the drc_index
- * corresponding to core number i.
+ * The first element of "ibm,drc-indexes" is the number of
+ * drc_indexes returned in the list. Hence i + 1 will get the
+ * drc_index corresponding to core number i.
*/
- WARN_ON(i > indexes[0]);
- ret = indexes[i + 1];
- rc = 0;
+ rc = of_property_read_u32_index(dn, "ibm,drc-indexes",
+ 0, &nr_drc_indexes);
+ if (rc)
+ goto err_of_node_put;
+
+ WARN_ON(i > nr_drc_indexes);
+ rc = of_property_read_u32_index(dn, "ibm,drc-indexes",
+ i + 1, &i_drc_index);
+ if (!rc)
+ ret = i_drc_index;
err_of_node_put:
of_node_put(dn);
--
2.20.1