From: Robin Murphy Date: Mon, 26 Sep 2016 15:50:55 +0000 (+0100) Subject: ARM: 8616/1: dt: Respect property size when parsing CPUs X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=c84cc7b9064a22aaf73c3a5fc4c073cd4d588c98;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git ARM: 8616/1: dt: Respect property size when parsing CPUs commit ba6dea4f7cedb4b1c17e36f4087675d817c2e24b upstream. Whilst MPIDR values themselves are less than 32 bits, it is still perfectly valid for a DT to have #address-cells > 1 in the CPUs node, resulting in the "reg" property having leading zero cell(s). In that situation, the big-endian nature of the data conspires with the current behaviour of only reading the first cell to cause the kernel to think all CPUs have ID 0, and become resoundingly unhappy as a consequence. Take the full property length into account when parsing CPUs so as to be correct under any circumstances. Cc: Russell King Signed-off-by: Robin Murphy Signed-off-by: Russell King Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c index 65addcbf5b30..b3b950fc8ea0 100644 --- a/arch/arm/kernel/devtree.c +++ b/arch/arm/kernel/devtree.c @@ -87,6 +87,8 @@ void __init arm_dt_init_cpu_maps(void) return; for_each_child_of_node(cpus, cpu) { + const __be32 *cell; + int prop_bytes; u32 hwid; if (of_node_cmp(cpu->type, "cpu")) @@ -98,7 +100,8 @@ void __init arm_dt_init_cpu_maps(void) * properties is considered invalid to build the * cpu_logical_map. */ - if (of_property_read_u32(cpu, "reg", &hwid)) { + cell = of_get_property(cpu, "reg", &prop_bytes); + if (!cell || prop_bytes < sizeof(*cell)) { pr_debug(" * %s missing reg property\n", cpu->full_name); of_node_put(cpu); @@ -106,10 +109,15 @@ void __init arm_dt_init_cpu_maps(void) } /* - * 8 MSBs must be set to 0 in the DT since the reg property + * Bits n:24 must be set to 0 in the DT since the reg property * defines the MPIDR[23:0]. */ - if (hwid & ~MPIDR_HWID_BITMASK) { + do { + hwid = be32_to_cpu(*cell++); + prop_bytes -= sizeof(*cell); + } while (!hwid && prop_bytes > 0); + + if (prop_bytes || (hwid & ~MPIDR_HWID_BITMASK)) { of_node_put(cpu); return; }