arch/arm64/kernel/suspend.c

Source file repositories/reference/linux-study-clean/arch/arm64/kernel/suspend.c

File Facts

System
Linux kernel
Corpus path
arch/arm64/kernel/suspend.c
Extension
.c
Size
5180 bytes
Lines
188
Domain
Architecture Layer
Bucket
arch/arm64
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// 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();
}

/*

Annotation

Implementation Notes