// SPDX-License-Identifier: GPL-2.0#include <linux/ftrace.h>#include <linux/percpu.h>#include <linux/slab.h>#include <linux/uaccess.h>#include <linux/pgtable.h>#include <linux/cpuidle.h>#include <asm/alternative.h>#include <asm/cacheflush.h>#include <asm/cpufeature.h>#include <asm/cpuidle.h>#include <asm/daifflags.h>#include <asm/debug-monitors.h>#include <asm/exec.h>#include <asm/fpsimd.h>#include <asm/mte.h>#include <asm/memory.h>#include <asm/mmu_context.h>#include <asm/smp_plat.h>#include <asm/suspend.h> /* * This is allocated by cpu_suspend_init(), and used to store a pointer to * the 'struct sleep_stack_data' the contains a particular CPUs state. */unsigned long *sleep_save_stash; /* * This hook is provided so that cpu_suspend code can restore HW * breakpoints as early as possible in the resume path, before reenabling * debug exceptions. Code cannot be run from a CPU PM notifier since by the * time the notifier runs debug exceptions might have been enabled already, * with HW breakpoints registers content still in an unknown state. */static int (*hw_breakpoint_restore)(unsigned int);void __init cpu_suspend_set_dbg_restorer(int (*hw_bp_restore)(unsigned int)){	/* Prevent multiple restore hook initializations */	if (WARN_ON(hw_breakpoint_restore))		return;	hw_breakpoint_restore = hw_bp_restore;} void notrace __cpu_suspend_exit(void){	unsigned int cpu = smp_processor_id(); 	mte_suspend_exit(); 	/*	 * We are resuming from reset with the idmap active in TTBR0_EL1.	 * We must uninstall the idmap and restore the expected MMU	 * state before we can possibly return to userspace.	 */	cpu_uninstall_idmap(); 	/* Restore CnP bit in TTBR1_EL1 */	if (system_supports_cnp())		cpu_enable_swapper_cnp(); 	/*	 * PSTATE was not saved over suspend/resume, re-enable any detected	 * features that might not have been set correctly.	 */	if (alternative_has_cap_unlikely(ARM64_HAS_DIT))		set_pstate_dit(1);	__uaccess_enable_hw_pan(); 	/*	 * Restore HW breakpoint registers to sane values	 * before debug exceptions are possibly reenabled	 * by cpu_suspend()s local_daif_restore() call.	 */	if (hw_breakpoint_restore)		hw_breakpoint_restore(cpu); 	/*	 * On resume, firmware implementing dynamic mitigation will	 * have turned the mitigation on. If the user has forcefully	 * disabled it, make sure their wishes are obeyed.	 */	spectre_v4_enable_mitigation(NULL); 	sme_suspend_exit(); 	/* Restore additional feature-specific configuration */	ptrauth_suspend_exit();} /* * cpu_suspend * * arg: argument to pass to the finisher function * fn: finisher function pointer * */int cpu_suspend(unsigned long arg, int (*fn)(unsigned long)){	int ret = 0;	unsigned long flags;	struct sleep_stack_data state; 	/*	 * Some portions of CPU state (e.g. PSTATE.{PAN,DIT}) are initialized	 * before alternatives are patched, but are only restored by	 * __cpu_suspend_exit() after alternatives are patched. To avoid	 * accidentally losing these bits we must not attempt to suspend until	 * after alternatives have been patched.	 */	WARN_ON(!system_capabilities_finalized()); 	/* Report any MTE async fault before going to suspend */	mte_suspend_enter(); 	/*	 * From this point debug exceptions are disabled to prevent	 * updates to mdscr register (saved and restored along with	 * general purpose registers) from kernel debuggers.	 *	 * Strictly speaking the trace_hardirqs_off() here is superfluous,	 * hardirqs should be firmly off by now. This really ought to use	 * something like raw_local_daif_save().	 *	 * This also unmasks interrupts in PMR in order to reliably	 * resume if we're using pseudo-NMIs.	 */	flags = local_daif_save(); 	/*	 * Function graph tracer state gets inconsistent when the kernel	 * calls functions that never return (aka suspend finishers) hence	 * disable graph tracing during their execution.	 */	pause_graph_tracing(); 	ct_cpuidle_enter(); 	if (__cpu_suspend_enter(&state)) {		/* Call the suspend finisher */		ret = fn(arg); 		/*		 * Never gets here, unless the suspend finisher fails.		 * Successful cpu_suspend() should return from cpu_resume(),		 * returning through this code path is considered an error		 * If the return value is set to 0 force ret = -EOPNOTSUPP		 * to make sure a proper error condition is propagated		 */		if (!ret)			ret = -EOPNOTSUPP; 		ct_cpuidle_exit();	} else {		ct_cpuidle_exit();		__cpu_suspend_exit();	} 	unpause_graph_tracing(); 	/*	 * Restore pstate flags. OS lock and mdscr have been already	 * restored, so from this point onwards, debugging is fully	 * reenabled if it was enabled when core started shutdown.	 */	local_daif_restore(flags); 	return ret;} static int __init cpu_suspend_init(void){	/* ctx_ptr is an array of physical addresses */	sleep_save_stash = kcalloc(mpidr_hash_size(), sizeof(*sleep_save_stash),				   GFP_KERNEL); 	if (WARN_ON(!sleep_save_stash))		return -ENOMEM; 	return 0;}early_initcall(cpu_suspend_init);