LoongArch: Add SMT (Simultaneous Multi-Threading) support

Loongson-3A6000 has SMT (Simultaneous Multi-Threading) support, each
physical core has two logical cores (threads). This patch add SMT probe
and scheduler support via ACPI PPTT.

If SCHED_SMT enabled, Loongson-3A6000 is treated as 4 cores, 8 threads;
If SCHED_SMT disabled, Loongson-3A6000 is treated as 8 cores, 8 threads.

Remove smp_num_siblings to support HMP (Heterogeneous Multi-Processing).

Signed-off-by: Liupu Wang <wangliupu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 72b6144..e06315b 100644 (file)
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -5,6 +5,7 @@ config LOONGARCH
        select ACPI
        select ACPI_GENERIC_GSI if ACPI
        select ACPI_MCFG if ACPI
+       select ACPI_PPTT if ACPI
        select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
        select ARCH_BINFMT_ELF_STATE
        select ARCH_ENABLE_MEMORY_HOTPLUG
@@ -376,6 +377,13 @@ config EFI_STUB
          This kernel feature allows the kernel to be loaded directly by
          EFI firmware without the use of a bootloader.
 
+config SCHED_SMT
+       bool "SMT scheduler support"
+       default y
+       help
+         Improves scheduler's performance when there are multiple
+         threads in one physical core.
+
 config SMP
        bool "Multi-Processing support"
        help

diff --git a/arch/loongarch/include/asm/acpi.h b/arch/loongarch/include/asm/acpi.h
index 976a810..5c78b5d 100644 (file)
--- a/arch/loongarch/include/asm/acpi.h
+++ b/arch/loongarch/include/asm/acpi.h
@@ -13,6 +13,7 @@ extern int acpi_strict;
 extern int acpi_disabled;
 extern int acpi_pci_disabled;
 extern int acpi_noirq;
+extern int pptt_enabled;
 
 #define acpi_os_ioremap acpi_os_ioremap
 void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size);
@@ -30,6 +31,14 @@ static inline bool acpi_has_cpu_in_madt(void)
 }
 
 extern struct list_head acpi_wakeup_device_list;
+extern struct acpi_madt_core_pic acpi_core_pic[NR_CPUS];
+
+extern int __init parse_acpi_topology(void);
+
+static inline u32 get_acpi_id_for_cpu(unsigned int cpu)
+{
+       return acpi_core_pic[cpu_logical_map(cpu)].processor_id;
+}
 
 #endif /* !CONFIG_ACPI */
 

diff --git a/arch/loongarch/include/asm/cpu-info.h b/arch/loongarch/include/asm/cpu-info.h
index cd73a6f..900589c 100644 (file)
--- a/arch/loongarch/include/asm/cpu-info.h
+++ b/arch/loongarch/include/asm/cpu-info.h
@@ -54,6 +54,7 @@ struct cpuinfo_loongarch {
        struct cache_desc       cache_leaves[CACHE_LEAVES_MAX];
        int                     core;   /* physical core number in package */
        int                     package;/* physical package number */
+       int                     global_id; /* physical global thread number */
        int                     vabits; /* Virtual Address size in bits */
        int                     pabits; /* Physical Address size in bits */
        unsigned int            ksave_mask; /* Usable KSave mask. */

diff --git a/arch/loongarch/kernel/acpi.c b/arch/loongarch/kernel/acpi.c
index 98f4311..9450e09 100644 (file)
--- a/arch/loongarch/kernel/acpi.c
+++ b/arch/loongarch/kernel/acpi.c
@@ -33,6 +33,8 @@ u64 acpi_saved_sp;
 
 #define PREFIX                 "ACPI: "
 
+struct acpi_madt_core_pic acpi_core_pic[NR_CPUS];
+
 void __init __iomem * __acpi_map_table(unsigned long phys, unsigned long size)
 {
 
@@ -99,6 +101,7 @@ acpi_parse_processor(union acpi_subtable_headers *header, const unsigned long en
 
        acpi_table_print_madt_entry(&header->common);
 #ifdef CONFIG_SMP
+       acpi_core_pic[processor->core_id] = *processor;
        set_processor_mask(processor->core_id, processor->flags);
 #endif
 
@@ -140,6 +143,35 @@ static void __init acpi_process_madt(void)
        loongson_sysconf.nr_cpus = num_processors;
 }
 
+int pptt_enabled;
+
+int __init parse_acpi_topology(void)
+{
+       int cpu, topology_id;
+
+       for_each_possible_cpu(cpu) {
+               topology_id = find_acpi_cpu_topology(cpu, 0);
+               if (topology_id < 0) {
+                       pr_warn("Invalid BIOS PPTT\n");
+                       return -ENOENT;
+               }
+
+               if (acpi_pptt_cpu_is_thread(cpu) <= 0)
+                       cpu_data[cpu].core = topology_id;
+               else {
+                       topology_id = find_acpi_cpu_topology(cpu, 1);
+                       if (topology_id < 0)
+                               return -ENOENT;
+
+                       cpu_data[cpu].core = topology_id;
+               }
+       }
+
+       pptt_enabled = 1;
+
+       return 0;
+}
+
 #ifndef CONFIG_SUSPEND
 int (*acpi_suspend_lowlevel)(void);
 #else

diff --git a/arch/loongarch/kernel/proc.c b/arch/loongarch/kernel/proc.c
index 0d82907..d4b2706 100644 (file)
--- a/arch/loongarch/kernel/proc.c
+++ b/arch/loongarch/kernel/proc.c
@@ -49,6 +49,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
        seq_printf(m, "processor\t\t: %ld\n", n);
        seq_printf(m, "package\t\t\t: %d\n", cpu_data[n].package);
        seq_printf(m, "core\t\t\t: %d\n", cpu_data[n].core);
+       seq_printf(m, "global_id\t\t: %d\n", cpu_data[n].global_id);
        seq_printf(m, "CPU Family\t\t: %s\n", __cpu_family[n]);
        seq_printf(m, "Model Name\t\t: %s\n", __cpu_full_name[n]);
        seq_printf(m, "CPU Revision\t\t: 0x%02x\n", version);

diff --git a/arch/loongarch/kernel/smp.c b/arch/loongarch/kernel/smp.c
index a858a46..255967f 100644 (file)
--- a/arch/loongarch/kernel/smp.c
+++ b/arch/loongarch/kernel/smp.c
@@ -8,6 +8,7 @@
  * Copyright (C) 2000, 2001 Silicon Graphics, Inc.
  * Copyright (C) 2000, 2001, 2003 Broadcom Corporation
  */
+#include <linux/acpi.h>
 #include <linux/cpu.h>
 #include <linux/cpumask.h>
 #include <linux/init.h>
@@ -37,10 +38,6 @@ EXPORT_SYMBOL(__cpu_number_map);
 int __cpu_logical_map[NR_CPUS];                /* Map logical to physical */
 EXPORT_SYMBOL(__cpu_logical_map);
 
-/* Number of threads (siblings) per CPU core */
-int smp_num_siblings = 1;
-EXPORT_SYMBOL(smp_num_siblings);
-
 /* Representing the threads (siblings) of each logical CPU */
 cpumask_t cpu_sibling_map[NR_CPUS] __read_mostly;
 EXPORT_SYMBOL(cpu_sibling_map);
@@ -229,9 +226,12 @@ void __init loongson_prepare_cpus(unsigned int max_cpus)
 {
        int i = 0;
 
+       parse_acpi_topology();
+
        for (i = 0; i < loongson_sysconf.nr_cpus; i++) {
                set_cpu_present(i, true);
                csr_mail_send(0, __cpu_logical_map[i], 0);
+               cpu_data[i].global_id = __cpu_logical_map[i];
        }
 
        per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
@@ -272,10 +272,10 @@ void loongson_init_secondary(void)
        numa_add_cpu(cpu);
 #endif
        per_cpu(cpu_state, cpu) = CPU_ONLINE;
-       cpu_data[cpu].core =
-                    cpu_logical_map(cpu) % loongson_sysconf.cores_per_package;
        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;
 }
 
 void loongson_smp_finish(void)
@@ -381,14 +381,10 @@ static inline void set_cpu_sibling_map(int cpu)
 
        cpumask_set_cpu(cpu, &cpu_sibling_setup_map);
 
-       if (smp_num_siblings <= 1)
-               cpumask_set_cpu(cpu, &cpu_sibling_map[cpu]);
-       else {
-               for_each_cpu(i, &cpu_sibling_setup_map) {
-                       if (cpus_are_siblings(cpu, i)) {
-                               cpumask_set_cpu(i, &cpu_sibling_map[cpu]);
-                               cpumask_set_cpu(cpu, &cpu_sibling_map[i]);
-                       }
+       for_each_cpu(i, &cpu_sibling_setup_map) {
+               if (cpus_are_siblings(cpu, i)) {
+                       cpumask_set_cpu(i, &cpu_sibling_map[cpu]);
+                       cpumask_set_cpu(cpu, &cpu_sibling_map[i]);
                }
        }
 }

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index ccbeab9..00dd309 100644 (file)
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -542,10 +542,10 @@ config ACPI_PFRUT
 
 if ARM64
 source "drivers/acpi/arm64/Kconfig"
+endif
 
 config ACPI_PPTT
        bool
-endif
 
 config ACPI_PCC
        bool "ACPI PCC Address Space"