5.0-stable review patch. If anyone has any objections, please let me know.
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From: Gautham R. Shenoy ego@linux.vnet.ibm.com
commit ce9afe08e71e3f7d64f337a6e932e50849230fc2 upstream.
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: e83636ac3334 ("pseries/drc-info: Search DRC properties for CPU indexes") Cc: stable@vger.kernel.org # v4.16+ Reported-by: Pavithra R. Prakash pavrampu@in.ibm.com Signed-off-by: Gautham R. Shenoy ego@linux.vnet.ibm.com Reviewed-by: Vaidyanathan Srinivasan svaidy@linux.vnet.ibm.com [mpe: Make the WARN_ON a WARN_ON_ONCE so it's not retriggerable] Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/powerpc/platforms/pseries/pseries_energy.c | 27 ++++++++++++++++-------- 1 file changed, 18 insertions(+), 9 deletions(-)
--- a/arch/powerpc/platforms/pseries/pseries_energy.c +++ b/arch/powerpc/platforms/pseries/pseries_energy.c @@ -77,18 +77,27 @@ static u32 cpu_to_drc_index(int cpu)
ret = drc.drc_index_start + (thread_index * drc.sequential_inc); } else { - const __be32 *indexes; - - indexes = of_get_property(dn, "ibm,drc-indexes", NULL); - if (indexes == NULL) - goto err_of_node_put; + u32 nr_drc_indexes, thread_drc_index;
/* - * The first element indexes[0] is the number of drc_indexes - * returned in the list. Hence thread_index+1 will get the - * drc_index corresponding to core number thread_index. + * The first element of ibm,drc-indexes array is the + * number of drc_indexes returned in the list. Hence + * 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;