Enable SMP boot on ACPI based platforms by using the RINTC structures in the MADT table. Signed-off-by: Sunil V L <sunilvl@xxxxxxxxxxxxxxxx> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Reviewed-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx> --- arch/riscv/include/asm/acpi.h | 2 + arch/riscv/kernel/smpboot.c | 72 ++++++++++++++++++++++++++++++++++- 2 files changed, 73 insertions(+), 1 deletion(-) diff --git a/arch/riscv/include/asm/acpi.h b/arch/riscv/include/asm/acpi.h index 2b3e78d5a13b..b26ba911f0a9 100644 --- a/arch/riscv/include/asm/acpi.h +++ b/arch/riscv/include/asm/acpi.h @@ -63,6 +63,8 @@ struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu); u32 get_acpi_id_for_cpu(int cpu); int acpi_get_riscv_isa(struct acpi_table_header *table, unsigned int cpu, const char **isa); + +static inline int acpi_numa_get_nid(unsigned int cpu) { return NUMA_NO_NODE; } #else static inline int acpi_get_riscv_isa(struct acpi_table_header *table, unsigned int cpu, const char **isa) diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c index 26214ddefaa4..6a854b200b72 100644 --- a/arch/riscv/kernel/smpboot.c +++ b/arch/riscv/kernel/smpboot.c @@ -8,6 +8,7 @@ * Copyright (C) 2017 SiFive */ +#include <linux/acpi.h> #include <linux/arch_topology.h> #include <linux/module.h> #include <linux/init.h> @@ -70,6 +71,72 @@ void __init smp_prepare_cpus(unsigned int max_cpus) } } +#ifdef CONFIG_ACPI +static unsigned int cpu_count = 1; + +static int __init acpi_parse_rintc(union acpi_subtable_headers *header, const unsigned long end) +{ + unsigned long hart; + static bool found_boot_cpu; + struct acpi_madt_rintc *processor = (struct acpi_madt_rintc *)header; + + /* + * Each RINTC structure in MADT will have a flag. If ACPI_MADT_ENABLED + * bit in the flag is not enabled, it means OS should not try to enable + * the cpu to which RINTC belongs. + */ + if (!(processor->flags & ACPI_MADT_ENABLED)) + return 0; + + if (BAD_MADT_ENTRY(processor, end)) + return -EINVAL; + + acpi_table_print_madt_entry(&header->common); + + hart = processor->hart_id; + if (hart == INVALID_HARTID) { + pr_warn("Invalid hartid\n"); + return 0; + } + + if (hart == cpuid_to_hartid_map(0)) { + BUG_ON(found_boot_cpu); + found_boot_cpu = true; + early_map_cpu_to_node(0, acpi_numa_get_nid(cpu_count)); + return 0; + } + + if (cpu_count >= NR_CPUS) { + pr_warn("NR_CPUS is too small for the number of ACPI tables.\n"); + return 0; + } + + cpuid_to_hartid_map(cpu_count) = hart; + early_map_cpu_to_node(cpu_count, acpi_numa_get_nid(cpu_count)); + cpu_count++; + + return 0; +} + +static void __init acpi_parse_and_init_cpus(void) +{ + int cpuid; + + cpu_set_ops(0); + + acpi_table_parse_madt(ACPI_MADT_TYPE_RINTC, acpi_parse_rintc, 0); + + for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) { + if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID) { + cpu_set_ops(cpuid); + set_cpu_possible(cpuid, true); + } + } +} +#else +#define acpi_parse_and_init_cpus(...) do { } while (0) +#endif + static void __init of_parse_and_init_cpus(void) { struct device_node *dn; @@ -118,7 +185,10 @@ static void __init of_parse_and_init_cpus(void) void __init setup_smp(void) { - of_parse_and_init_cpus(); + if (acpi_disabled) + of_parse_and_init_cpus(); + else + acpi_parse_and_init_cpus(); } static int start_secondary_cpu(int cpu, struct task_struct *tidle) -- 2.34.1