Create cpu topology based on MPIDR. When hardware sets MPIDR to sane values, this method will always work. Therefore it should also work well as the fallback method. [1]
[1] http://www.spinics.net/lists/arm-kernel/msg317445.html Signed-off-by: Zi Shen Lim <z...@broadcom.com> --- arch/arm64/include/asm/cputype.h | 2 ++ arch/arm64/kernel/topology.c | 31 +++++++++++++++++++++++++++++++ 2 files changed, 33 insertions(+) diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h index c404fb0..7639e8b 100644 --- a/arch/arm64/include/asm/cputype.h +++ b/arch/arm64/include/asm/cputype.h @@ -18,6 +18,8 @@ #define INVALID_HWID ULONG_MAX +#define MPIDR_UP_BITMASK (0x1 << 30) +#define MPIDR_MT_BITMASK (0x1 << 24) #define MPIDR_HWID_BITMASK 0xff00ffffff #define MPIDR_LEVEL_BITS_SHIFT 3 diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 3e06b0b..ef3bb7e 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -19,6 +19,7 @@ #include <linux/nodemask.h> #include <linux/sched.h> +#include <asm/cputype.h> #include <asm/topology.h> /* @@ -71,6 +72,36 @@ static void update_siblings_masks(unsigned int cpuid) void store_cpu_topology(unsigned int cpuid) { + struct cpu_topology *cpuid_topo = &cpu_topology[cpuid]; + u64 mpidr; + + mpidr = read_cpuid_mpidr(); + + /* Create cpu topology mapping based on MPIDR. */ + if (mpidr & MPIDR_UP_BITMASK) { + /* Uniprocessor system */ + cpuid_topo->thread_id = -1; + cpuid_topo->core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0); + cpuid_topo->cluster_id = -1; + } else { + /* Multiprocessor system */ + if (mpidr & MPIDR_MT_BITMASK) { + /* Multi-threads per core */ + cpuid_topo->thread_id = MPIDR_AFFINITY_LEVEL(mpidr, 0); + cpuid_topo->core_id = MPIDR_AFFINITY_LEVEL(mpidr, 1); + cpuid_topo->cluster_id = MPIDR_AFFINITY_LEVEL(mpidr, 2); + } else { + /* Single-thread per core */ + cpuid_topo->thread_id = -1; + cpuid_topo->core_id = MPIDR_AFFINITY_LEVEL(mpidr, 0); + cpuid_topo->cluster_id = MPIDR_AFFINITY_LEVEL(mpidr, 1); + } + } + + pr_info("CPU%u: cluster %d core %d thread %d mpidr %llx\n", + cpuid, cpuid_topo->cluster_id, cpuid_topo->core_id, + cpuid_topo->thread_id, mpidr); + update_siblings_masks(cpuid); } -- 1.8.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
