Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 736d474f authored by Suzuki K. Poulose's avatar Suzuki K. Poulose Committed by Catalin Marinas
Browse files

arm64: Consolidate hotplug notifier for instruction emulation 



As of now each insn_emulation has a cpu hotplug notifier that
enables/disables the CPU feature bit for the functionality. This
patch re-arranges the code, such that there is only one notifier
that runs through the list of registered emulation hooks and runs
their corresponding set_hw_mode.

We do nothing when a CPU is dying as we will set the appropriate bits
as it comes back online based on the state of the hooks.

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarSuzuki K. Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Punit Agrawal <punit.agrawal@arm.com>
[catalin.marinas@arm.com: fix pr_warn compilation error]
[catalin.marinas@arm.com: remove unnecessary "insn" check]
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 04597a65

arch/arm64/include/asm/cputype.h

+2 −0
Original line number Diff line number Diff line
@@ -81,6 +81,8 @@ 
#define ID_AA64MMFR0_BIGEND(mmfr0)	\

	(((mmfr0) & ID_AA64MMFR0_BIGEND_MASK) >> ID_AA64MMFR0_BIGEND_SHIFT)



#define SCTLR_EL1_CP15BEN	(0x1 << 5)



#ifndef __ASSEMBLY__



/*

arch/arm64/kernel/armv8_deprecated.c

+77 −48
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <asm/system_misc.h>

#include <asm/traps.h>

#include <asm/uaccess.h>

#include <asm/cpufeature.h>



#define CREATE_TRACE_POINTS

#include "trace-events-emulation.h"
@@ -85,6 +86,57 @@ static void remove_emulation_hooks(struct insn_emulation_ops *ops) 
	pr_notice("Removed %s emulation handler\n", ops->name);

}



static void enable_insn_hw_mode(void *data)

{

	struct insn_emulation *insn = (struct insn_emulation *)data;

	if (insn->ops->set_hw_mode)

		insn->ops->set_hw_mode(true);

}



static void disable_insn_hw_mode(void *data)

{

	struct insn_emulation *insn = (struct insn_emulation *)data;

	if (insn->ops->set_hw_mode)

		insn->ops->set_hw_mode(false);

}



/* Run set_hw_mode(mode) on all active CPUs */

static int run_all_cpu_set_hw_mode(struct insn_emulation *insn, bool enable)

{

	if (!insn->ops->set_hw_mode)

		return -EINVAL;

	if (enable)

		on_each_cpu(enable_insn_hw_mode, (void *)insn, true);

	else

		on_each_cpu(disable_insn_hw_mode, (void *)insn, true);

	return 0;

}



/*

 * Run set_hw_mode for all insns on a starting CPU.

 * Returns:

 *  0 		- If all the hooks ran successfully.

 * -EINVAL	- At least one hook is not supported by the CPU.

 */

static int run_all_insn_set_hw_mode(unsigned long cpu)

{

	int rc = 0;

	unsigned long flags;

	struct insn_emulation *insn;



	raw_spin_lock_irqsave(&insn_emulation_lock, flags);

	list_for_each_entry(insn, &insn_emulation, node) {

		bool enable = (insn->current_mode == INSN_HW);

		if (insn->ops->set_hw_mode && insn->ops->set_hw_mode(enable)) {

			pr_warn("CPU[%ld] cannot support the emulation of %s",

				cpu, insn->ops->name);

			rc = -EINVAL;

		}

	}

	raw_spin_unlock_irqrestore(&insn_emulation_lock, flags);

	return rc;

}



static int update_insn_emulation_mode(struct insn_emulation *insn,

				       enum insn_emulation_mode prev)

{
@@ -97,10 +149,8 @@ static int update_insn_emulation_mode(struct insn_emulation *insn, 
		remove_emulation_hooks(insn->ops);

		break;

	case INSN_HW:

		if (insn->ops->set_hw_mode) {

			insn->ops->set_hw_mode(false);

		if (!run_all_cpu_set_hw_mode(insn, false))

			pr_notice("Disabled %s support\n", insn->ops->name);

		}

		break;

	}
@@ -111,10 +161,9 @@ static int update_insn_emulation_mode(struct insn_emulation *insn, 
		register_emulation_hooks(insn->ops);

		break;

	case INSN_HW:

		if (insn->ops->set_hw_mode && insn->ops->set_hw_mode(true))

		ret = run_all_cpu_set_hw_mode(insn, true);

		if (!ret)

			pr_notice("Enabled %s support\n", insn->ops->name);

		else

			ret = -EINVAL;

		break;

	}
@@ -133,6 +182,8 @@ static void register_insn_emulation(struct insn_emulation_ops *ops) 
	switch (ops->status) {

	case INSN_DEPRECATED:

		insn->current_mode = INSN_EMULATE;

		/* Disable the HW mode if it was turned on at early boot time */

		run_all_cpu_set_hw_mode(insn, false);

		insn->max = INSN_HW;

		break;

	case INSN_OBSOLETE:
@@ -453,8 +504,6 @@ static int cp15barrier_handler(struct pt_regs *regs, u32 instr) 
	return 0;

}



#define SCTLR_EL1_CP15BEN (1 << 5)



static inline void config_sctlr_el1(u32 clear, u32 set)

{

	u32 val;
@@ -465,48 +514,13 @@ static inline void config_sctlr_el1(u32 clear, u32 set) 
	asm volatile("msr sctlr_el1, %0" : : "r" (val));

}



static void enable_cp15_ben(void *info)

static int cp15_barrier_set_hw_mode(bool enable)

{

	if (enable)

		config_sctlr_el1(0, SCTLR_EL1_CP15BEN);

}



static void disable_cp15_ben(void *info)

{

	else

		config_sctlr_el1(SCTLR_EL1_CP15BEN, 0);

}



static int cpu_hotplug_notify(struct notifier_block *b,

			      unsigned long action, void *hcpu)

{

	switch (action) {

	case CPU_STARTING:

	case CPU_STARTING_FROZEN:

		enable_cp15_ben(NULL);

		return NOTIFY_DONE;

	case CPU_DYING:

	case CPU_DYING_FROZEN:

		disable_cp15_ben(NULL);

		return NOTIFY_DONE;

	}



	return NOTIFY_OK;

}



static struct notifier_block cpu_hotplug_notifier = {

	.notifier_call = cpu_hotplug_notify,

};



static int cp15_barrier_set_hw_mode(bool enable)

{

	if (enable) {

		register_cpu_notifier(&cpu_hotplug_notifier);

		on_each_cpu(enable_cp15_ben, NULL, true);

	} else {

		unregister_cpu_notifier(&cpu_hotplug_notifier);

		on_each_cpu(disable_cp15_ben, NULL, true);

	}



	return true;

	return 0;

}



static struct undef_hook cp15_barrier_hooks[] = {
@@ -534,6 +548,20 @@ static struct insn_emulation_ops cp15_barrier_ops = { 
	.set_hw_mode = cp15_barrier_set_hw_mode,

};



static int insn_cpu_hotplug_notify(struct notifier_block *b,

			      unsigned long action, void *hcpu)

{

	int rc = 0;

	if ((action & ~CPU_TASKS_FROZEN) == CPU_STARTING)

		rc = run_all_insn_set_hw_mode((unsigned long)hcpu);



	return notifier_from_errno(rc);

}



static struct notifier_block insn_cpu_hotplug_notifier = {

	.notifier_call = insn_cpu_hotplug_notify,

};



/*

 * Invoked as late_initcall, since not needed before init spawned.

 */
@@ -545,6 +573,7 @@ static int __init armv8_deprecated_init(void) 
	if (IS_ENABLED(CONFIG_CP15_BARRIER_EMULATION))

		register_insn_emulation(&cp15_barrier_ops);



	register_cpu_notifier(&insn_cpu_hotplug_notifier);

	register_insn_emulation_sysctl(ctl_abi);



	return 0;