Unverified Commit 62ff2622 authored by Samuel Holland's avatar Samuel Holland Committed by Palmer Dabbelt
Browse files

riscv: Use the same CPU operations for all CPUs 



RISC-V provides no binding (ACPI or DT) to describe per-cpu start/stop
operations, so cpu_set_ops() will always detect the same operations for
every CPU. Replace the cpu_ops array with a single pointer to save space
and reduce boot time.

Signed-off-by: default avatarSamuel Holland <samuel.holland@sifive.com>
Reviewed-by: default avatarConor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20231121234736.3489608-4-samuel.holland@sifive.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 79093f3e

arch/riscv/include/asm/cpu_ops.h

+2 −2
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ struct cpu_operations { 
};



extern const struct cpu_operations cpu_ops_spinwait;

extern const struct cpu_operations *cpu_ops[NR_CPUS];

void __init cpu_set_ops(int cpu);

extern const struct cpu_operations *cpu_ops;

void __init cpu_set_ops(void);



#endif /* ifndef __ASM_CPU_OPS_H */

arch/riscv/kernel/cpu-hotplug.c

+5 −5
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ 


bool cpu_has_hotplug(unsigned int cpu)

{

	if (cpu_ops[cpu]->cpu_stop)

	if (cpu_ops->cpu_stop)

		return true;



	return false;
@@ -31,7 +31,7 @@ int __cpu_disable(void) 
{

	unsigned int cpu = smp_processor_id();



	if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_stop)

	if (!cpu_ops->cpu_stop)

		return -EOPNOTSUPP;



	remove_cpu_topology(cpu);
@@ -55,8 +55,8 @@ void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu) 
	pr_notice("CPU%u: off\n", cpu);



	/* Verify from the firmware if the cpu is really stopped*/

	if (cpu_ops[cpu]->cpu_is_stopped)

		ret = cpu_ops[cpu]->cpu_is_stopped(cpu);

	if (cpu_ops->cpu_is_stopped)

		ret = cpu_ops->cpu_is_stopped(cpu);

	if (ret)

		pr_warn("CPU%d may not have stopped: %d\n", cpu, ret);

}
@@ -70,7 +70,7 @@ void __noreturn arch_cpu_idle_dead(void) 


	cpuhp_ap_report_dead();



	cpu_ops[smp_processor_id()]->cpu_stop();

	cpu_ops->cpu_stop();

	/* It should never reach here */

	BUG();

}

arch/riscv/kernel/cpu_ops.c

+5 −7
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ 
#include <asm/sbi.h>

#include <asm/smp.h>



const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;

const struct cpu_operations *cpu_ops __ro_after_init = &cpu_ops_spinwait;



extern const struct cpu_operations cpu_ops_sbi;

#ifndef CONFIG_RISCV_BOOT_SPINWAIT
@@ -22,14 +22,12 @@ const struct cpu_operations cpu_ops_spinwait = { 
};

#endif



void __init cpu_set_ops(int cpuid)

void __init cpu_set_ops(void)

{

#if IS_ENABLED(CONFIG_RISCV_SBI)

	if (sbi_probe_extension(SBI_EXT_HSM)) {

		if (!cpuid)

		pr_info("SBI HSM extension detected\n");

		cpu_ops[cpuid] = &cpu_ops_sbi;

	} else

		cpu_ops = &cpu_ops_sbi;

	}

#endif

		cpu_ops[cpuid] = &cpu_ops_spinwait;

}

arch/riscv/kernel/smp.c

+1 −1
Original line number Diff line number Diff line
@@ -81,7 +81,7 @@ static inline void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs) 


#ifdef CONFIG_HOTPLUG_CPU

	if (cpu_has_hotplug(cpu))

		cpu_ops[cpu]->cpu_stop();

		cpu_ops->cpu_stop();

#endif



	for(;;)

arch/riscv/kernel/smpboot.c

+5 −8
Original line number Diff line number Diff line
@@ -166,25 +166,22 @@ void __init setup_smp(void) 
{

	int cpuid;



	cpu_set_ops(0);

	cpu_set_ops();



	if (acpi_disabled)

		of_parse_and_init_cpus();

	else

		acpi_parse_and_init_cpus();



	for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) {

		if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID) {

			cpu_set_ops(cpuid);

	for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++)

		if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID)

			set_cpu_possible(cpuid, true);

}

	}

}



static int start_secondary_cpu(int cpu, struct task_struct *tidle)

{

	if (cpu_ops[cpu]->cpu_start)

		return cpu_ops[cpu]->cpu_start(cpu, tidle);

	if (cpu_ops->cpu_start)

		return cpu_ops->cpu_start(cpu, tidle);



	return -EOPNOTSUPP;

}