From 80708677fab44a1489a089e162455dfb4dd722cd Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 4 Nov 2014 10:50:16 +0000 Subject: [PATCH] arm64: log physical ID of boot CPU In certain debugging scenarios it's useful to know the physical ID (i.e. the MPIDR_EL1.Aff* fields) of the boot CPU, but we don't currently log this as we do for 32-bit ARM kernels. This patch makes the kernel log the physical ID of the boot CPU early in the boot process. The CPU logical map initialisation is folded in to smp_setup_processor_id (which contrary to its name is also called by UP kernels). This is called before setup_arch, so should not adversely affect existing cpu_logical_map users. Acked-by: Sudeep Holla Acked-by: Catalin Marinas Acked-by: Lorenzo Pieralisis Signed-off-by: Mark Rutland Signed-off-by: Will Deacon --- arch/arm64/kernel/setup.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index cbeaa2f3844b..c73714b6aa96 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -116,12 +116,16 @@ void __init early_print(const char *str, ...) void __init smp_setup_processor_id(void) { + u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK; + cpu_logical_map(0) = mpidr; + /* * clear __my_cpu_offset on boot CPU to avoid hang caused by * using percpu variable early, for example, lockdep will * access percpu variable inside lock_release */ set_my_cpu_offset(0); + pr_info("Booting Linux on physical CPU 0x%lx\n", (unsigned long)mpidr); } bool arch_match_cpu_phys_id(int cpu, u64 phys_id) @@ -399,7 +403,6 @@ void __init setup_arch(char **cmdline_p) psci_init(); - cpu_logical_map(0) = read_cpuid_mpidr() & MPIDR_HWID_BITMASK; cpu_read_bootcpu_ops(); #ifdef CONFIG_SMP smp_init_cpus(); -- 2.11.0