Unverified Commit ce92546c authored by Sunil V L's avatar Sunil V L Committed by Palmer Dabbelt
Browse files

RISC-V: smpboot: Add ACPI support in setup_smp() 



Enable SMP boot on ACPI based platforms by using the RINTC
structures in the MADT table.

Signed-off-by: default avatarSunil V L <sunilvl@ventanamicro.com>
Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: default avatarConor Dooley <conor.dooley@microchip.com>
Reviewed-by: default avatarAndrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20230515054928.2079268-13-sunilvl@ventanamicro.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 61946127

arch/riscv/include/asm/acpi.h

+2 −0
Original line number Diff line number Diff line
@@ -64,6 +64,8 @@ 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 void acpi_init_rintc_map(void) { }

static inline struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu)

arch/riscv/kernel/smpboot.c

+71 −1
Original line number Diff line number Diff line
@@ -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)

{

	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)