Commit ce9afe08 authored by Gautham R. Shenoy's avatar Gautham R. Shenoy Committed by Michael Ellerman

powerpc/pseries/energy: Use OF accessor functions to read ibm,drc-indexes

In cpu_to_drc_index() in the case when FW_FEATURE_DRC_INFO is absent,
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 OS-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.

Fixes: e83636ac ("pseries/drc-info: Search DRC properties for CPU indexes")
Cc: stable@vger.kernel.org # v4.16+
Reported-by: default avatarPavithra R. Prakash <pavrampu@in.ibm.com>
Signed-off-by: default avatarGautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: default avatarVaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
[mpe: Make the WARN_ON a WARN_ON_ONCE so it's not retriggerable]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent d9470757
...@@ -77,18 +77,27 @@ static u32 cpu_to_drc_index(int cpu) ...@@ -77,18 +77,27 @@ static u32 cpu_to_drc_index(int cpu)
ret = drc.drc_index_start + (thread_index * drc.sequential_inc); ret = drc.drc_index_start + (thread_index * drc.sequential_inc);
} else { } else {
const __be32 *indexes; u32 nr_drc_indexes, thread_drc_index;
indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
if (indexes == NULL)
goto err_of_node_put;
/* /*
* The first element indexes[0] is the number of drc_indexes * The first element of ibm,drc-indexes array is the
* returned in the list. Hence thread_index+1 will get the * number of drc_indexes returned in the list. Hence
* drc_index corresponding to core number thread_index. * thread_index+1 will get the drc_index corresponding
* to core number thread_index.
*/ */
ret = indexes[thread_index + 1]; rc = of_property_read_u32_index(dn, "ibm,drc-indexes",
0, &nr_drc_indexes);
if (rc)
goto err_of_node_put;
WARN_ON_ONCE(thread_index > nr_drc_indexes);
rc = of_property_read_u32_index(dn, "ibm,drc-indexes",
thread_index + 1,
&thread_drc_index);
if (rc)
goto err_of_node_put;
ret = thread_drc_index;
} }
rc = 0; rc = 0;
......
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