From: Rong Bao Date: Thu, 23 Jul 2026 14:27:29 +0000 (+0800) Subject: LoongArch: Retrieve CPU package ID from PPTT when available X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=4e8f58620f6717f72f3d88a2c8f25c0c656d0ba7;p=thirdparty%2Fkernel%2Flinux.git LoongArch: Retrieve CPU package ID from PPTT when available Currently, the LoongArch CPU topology initialization code calculates each core's package ID by dividing its physical ID by loongson_sysconf. cores_per_package. This relies on the assumption that cores_per_package counts in the same domain as physical IDs. On Loongson-3B6000 (XB612B0V_1.2), cores_per_package matches the visible core count -- 24 in this case. However, the physical IDs range from 0 to 31 in a noncontinuous fashion: $ cat /proc/cpuinfo | grep -i -F 'global_id' global_id : 0 global_id : 1 global_id : 4 global_id : 5 global_id : 6 global_id : 7 global_id : 8 global_id : 9 global_id : 10 global_id : 11 global_id : 14 global_id : 15 global_id : 16 global_id : 17 global_id : 20 global_id : 21 global_id : 22 global_id : 23 global_id : 26 global_id : 27 global_id : 28 global_id : 29 global_id : 30 global_id : 31 Retrieve the exact package ID from ACPI PPTT when available, in the same style as retrieving the core ID and thread ID in parse_acpi_topology(). Use this information in loongson_init_secondary() when the PPTT readout is successful. The original division logic is kept as a fallback. Meanwhile, since some existing code paths like loongson3_cpufreq expect a continuous integer sequence of package IDs in [0, MAX_PACKAGES) when retrieving from cpu_data[], here we also canonicalize the package ID to be filled in parse_acpi_topology() to meet such an expectation. Cc: stable@vger.kernel.org Tested-by: Mingcong Bai Co-developed-by: Xi Ruoyao Signed-off-by: Xi Ruoyao Signed-off-by: Rong Bao Signed-off-by: Huacai Chen --- diff --git a/arch/loongarch/kernel/acpi.c b/arch/loongarch/kernel/acpi.c index 8f650c9ffecd..873e90990771 100644 --- a/arch/loongarch/kernel/acpi.c +++ b/arch/loongarch/kernel/acpi.c @@ -201,10 +201,12 @@ static void __init acpi_process_madt(void) } int pptt_enabled; +static int acpi_nr_packages; +static int acpi_package_ids[MAX_PACKAGES]; int __init parse_acpi_topology(void) { - int cpu, topology_id; + int i, cpu, topology_id; for_each_possible_cpu(cpu) { topology_id = find_acpi_cpu_topology(cpu, 0); @@ -222,6 +224,29 @@ int __init parse_acpi_topology(void) cpu_data[cpu].core = topology_id; } + + topology_id = find_acpi_cpu_topology_package(cpu); + if (topology_id < 0) { + pr_warn("Invalid BIOS PPTT\n"); + return -ENOENT; + } + + for (i = 0; i < acpi_nr_packages; i++) + if (acpi_package_ids[i] == topology_id) + break; + + if (i == acpi_nr_packages) + acpi_package_ids[acpi_nr_packages++] = topology_id; + + cpu_data[cpu].package = topology_id; + } + + for_each_possible_cpu(cpu) { + for (i = 0; i < acpi_nr_packages; i++) + if (cpu_data[cpu].package == acpi_package_ids[i]) { + cpu_data[cpu].package = i; /* Canonicalize */ + break; + } } pptt_enabled = 1; diff --git a/arch/loongarch/kernel/smp.c b/arch/loongarch/kernel/smp.c index 5d792256bbb9..d4b5d1b6bb01 100644 --- a/arch/loongarch/kernel/smp.c +++ b/arch/loongarch/kernel/smp.c @@ -426,10 +426,10 @@ void loongson_init_secondary(void) numa_add_cpu(cpu); #endif per_cpu(cpu_state, cpu) = CPU_ONLINE; - cpu_data[cpu].package = - cpu_logical_map(cpu) / loongson_sysconf.cores_per_package; cpu_data[cpu].core = pptt_enabled ? cpu_data[cpu].core : cpu_logical_map(cpu) % loongson_sysconf.cores_per_package; + cpu_data[cpu].package = pptt_enabled ? cpu_data[cpu].package : + cpu_logical_map(cpu) / loongson_sysconf.cores_per_package; cpu_data[cpu].global_id = cpu_logical_map(cpu); }