Unverified Commit 5634d9c2 authored by Palmer Dabbelt's avatar Palmer Dabbelt
Browse files

Merge patch series "riscv: CPU operations cleanup" 

Samuel Holland <samuel.holland@sifive.com> says:

This series cleans up some duplicated and dead code around the RISC-V
CPU operations, that was copied from arm64 but is not needed here. The
result is a bit of memory savings and removal of a few SBI calls during
boot, with no functional change.

* b4-shazam-merge:
  riscv: Use the same CPU operations for all CPUs
  riscv: Remove unused members from struct cpu_operations
  riscv: Deduplicate code in setup_smp()

Link: https://lore.kernel.org/r/20231121234736.3489608-1-samuel.holland@sifive.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parents b7b4e4d7 62ff2622

arch/riscv/include/asm/cpu_ops.h

+2 −12
Original line number Diff line number Diff line
@@ -13,33 +13,23 @@ 
/**

 * struct cpu_operations - Callback operations for hotplugging CPUs.

 *

 * @name:		Name of the boot protocol.

 * @cpu_prepare:	Early one-time preparation step for a cpu. If there

 *			is a mechanism for doing so, tests whether it is

 *			possible to boot the given HART.

 * @cpu_start:		Boots a cpu into the kernel.

 * @cpu_disable:	Prepares a cpu to die. May fail for some

 *			mechanism-specific reason, which will cause the hot

 *			unplug to be aborted. Called from the cpu to be killed.

 * @cpu_stop:		Makes a cpu leave the kernel. Must not fail. Called from

 *			the cpu being stopped.

 * @cpu_is_stopped:	Ensures a cpu has left the kernel. Called from another

 *			cpu.

 */

struct cpu_operations {

	const char	*name;

	int		(*cpu_prepare)(unsigned int cpu);

	int		(*cpu_start)(unsigned int cpu,

				     struct task_struct *tidle);

#ifdef CONFIG_HOTPLUG_CPU

	int		(*cpu_disable)(unsigned int cpu);

	void		(*cpu_stop)(void);

	int		(*cpu_is_stopped)(unsigned int cpu);

#endif

};



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

+6 −13
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;
@@ -29,25 +29,18 @@ bool cpu_has_hotplug(unsigned int cpu) 
 */

int __cpu_disable(void)

{

	int ret = 0;

	unsigned int cpu = smp_processor_id();



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

	if (!cpu_ops->cpu_stop)

		return -EOPNOTSUPP;



	if (cpu_ops[cpu]->cpu_disable)

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



	if (ret)

		return ret;



	remove_cpu_topology(cpu);

	numa_remove_cpu(cpu);

	set_cpu_online(cpu, false);

	riscv_ipi_disable();

	irq_migrate_all_off_this_cpu();



	return ret;

	return 0;

}



#ifdef CONFIG_HOTPLUG_CPU
@@ -62,8 +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);

}
@@ -77,7 +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 −9
Original line number Diff line number Diff line
@@ -13,25 +13,21 @@ 
#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

const struct cpu_operations cpu_ops_spinwait = {

	.name		= "",

	.cpu_prepare	= NULL,

	.cpu_start	= NULL,

};

#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/cpu_ops_sbi.c

+0 −19
Original line number Diff line number Diff line
@@ -79,23 +79,7 @@ static int sbi_cpu_start(unsigned int cpuid, struct task_struct *tidle) 
	return sbi_hsm_hart_start(hartid, boot_addr, hsm_data);

}



static int sbi_cpu_prepare(unsigned int cpuid)

{

	if (!cpu_ops_sbi.cpu_start) {

		pr_err("cpu start method not defined for CPU [%d]\n", cpuid);

		return -ENODEV;

	}

	return 0;

}



#ifdef CONFIG_HOTPLUG_CPU

static int sbi_cpu_disable(unsigned int cpuid)

{

	if (!cpu_ops_sbi.cpu_stop)

		return -EOPNOTSUPP;

	return 0;

}



static void sbi_cpu_stop(void)

{

	int ret;
@@ -118,11 +102,8 @@ static int sbi_cpu_is_stopped(unsigned int cpuid) 
#endif



const struct cpu_operations cpu_ops_sbi = {

	.name		= "sbi",

	.cpu_prepare	= sbi_cpu_prepare,

	.cpu_start	= sbi_cpu_start,

#ifdef CONFIG_HOTPLUG_CPU

	.cpu_disable	= sbi_cpu_disable,

	.cpu_stop	= sbi_cpu_stop,

	.cpu_is_stopped	= sbi_cpu_is_stopped,

#endif

arch/riscv/kernel/cpu_ops_spinwait.c

+0 −11
Original line number Diff line number Diff line
@@ -39,15 +39,6 @@ static void cpu_update_secondary_bootdata(unsigned int cpuid, 
	WRITE_ONCE(__cpu_spinwait_task_pointer[hartid], tidle);

}



static int spinwait_cpu_prepare(unsigned int cpuid)

{

	if (!cpu_ops_spinwait.cpu_start) {

		pr_err("cpu start method not defined for CPU [%d]\n", cpuid);

		return -ENODEV;

	}

	return 0;

}



static int spinwait_cpu_start(unsigned int cpuid, struct task_struct *tidle)

{

	/*
@@ -64,7 +55,5 @@ static int spinwait_cpu_start(unsigned int cpuid, struct task_struct *tidle) 
}



const struct cpu_operations cpu_ops_spinwait = {

	.name		= "spinwait",

	.cpu_prepare	= spinwait_cpu_prepare,

	.cpu_start	= spinwait_cpu_start,

};