arch/arm64/kernel/acpi.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *  ARM64 Specific Low-Level ACPI Boot Support
  *
  *  Copyright (C) 2013-2014, Linaro Ltd.
  *	Author: Al Stone <al.stone@linaro.org>
  *	Author: Graeme Gregory <graeme.gregory@linaro.org>
  *	Author: Hanjun Guo <hanjun.guo@linaro.org>
  *	Author: Tomasz Nowicki <tomasz.nowicki@linaro.org>
  *	Author: Naresh Bhat <naresh.bhat@linaro.org>
  */

 #define pr_fmt(fmt) "ACPI: " fmt

 #include <linux/acpi.h>
 #include <linux/arm-smccc.h>
 #include <linux/cpumask.h>
 #include <linux/efi.h>
 #include <linux/efi-bgrt.h>
 #include <linux/init.h>
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
 #include <linux/irq_work.h>
 #include <linux/memblock.h>
 #include <linux/of_fdt.h>
 #include <linux/libfdt.h>
 #include <linux/smp.h>
 #include <linux/serial_core.h>
 #include <linux/suspend.h>
 #include <linux/pgtable.h>

 #include <acpi/ghes.h>
 #include <acpi/processor.h>
 #include <asm/cputype.h>
 #include <asm/cpu_ops.h>
 #include <asm/daifflags.h>
 #include <asm/smp_plat.h>

 int acpi_noirq = 1;		/* skip ACPI IRQ initialization */
 int acpi_disabled = 1;
 EXPORT_SYMBOL(acpi_disabled);

 int acpi_pci_disabled = 1;	/* skip ACPI PCI scan and IRQ initialization */
 EXPORT_SYMBOL(acpi_pci_disabled);

 static bool param_acpi_off __initdata;
 static bool param_acpi_on __initdata;
 static bool param_acpi_force __initdata;
 static bool param_acpi_nospcr __initdata;

 static int __init parse_acpi(char *arg)
 {
 	if (!arg)
 		return -EINVAL;

 	/* "acpi=off" disables both ACPI table parsing and interpreter */
 	if (strcmp(arg, "off") == 0)
 		param_acpi_off = true;
 	else if (strcmp(arg, "on") == 0) /* prefer ACPI over DT */
 		param_acpi_on = true;
 	else if (strcmp(arg, "force") == 0) /* force ACPI to be enabled */
 		param_acpi_force = true;
 	else if (strcmp(arg, "nospcr") == 0) /* disable SPCR as default console */
 		param_acpi_nospcr = true;
 	else
 		return -EINVAL;	/* Core will print when we return error */

 	return 0;
 }
 early_param("acpi", parse_acpi);

 static bool __init dt_is_stub(void)
 {
 	int node;

 	fdt_for_each_subnode(node, initial_boot_params, 0) {
 		const char *name = fdt_get_name(initial_boot_params, node, NULL);
 		if (strcmp(name, "chosen") == 0)
 			continue;
 		if (strcmp(name, "hypervisor") == 0 &&
 		    of_flat_dt_is_compatible(node, "xen,xen"))
 			continue;

 		return false;
 	}

 	return true;
 }

 /*
  * __acpi_map_table() will be called before page_init(), so early_ioremap()
  * or early_memremap() should be called here to for ACPI table mapping.
  */
 void __init __iomem *__acpi_map_table(unsigned long phys, unsigned long size)
 {
 	if (!size)
 		return NULL;

 	return early_memremap(phys, size);
 }

 void __init __acpi_unmap_table(void __iomem *map, unsigned long size)
 {
 	if (!map || !size)
 		return;

 	early_memunmap(map, size);
 }

 bool __init acpi_psci_present(void)
 {
 	return acpi_gbl_FADT.arm_boot_flags & ACPI_FADT_PSCI_COMPLIANT;
 }

 /* Whether HVC must be used instead of SMC as the PSCI conduit */
 bool acpi_psci_use_hvc(void)
 {
 	return acpi_gbl_FADT.arm_boot_flags & ACPI_FADT_PSCI_USE_HVC;
 }

 /*
  * acpi_fadt_sanity_check() - Check FADT presence and carry out sanity
  *			      checks on it
  *
  * Return 0 on success,  <0 on failure
  */
 static int __init acpi_fadt_sanity_check(void)
 {
 	struct acpi_table_header *table;
 	struct acpi_table_fadt *fadt;
 	acpi_status status;
 	int ret = 0;

 	/*
 	 * FADT is required on arm64; retrieve it to check its presence
 	 * and carry out revision and ACPI HW reduced compliancy tests
 	 */
 	status = acpi_get_table(ACPI_SIG_FADT, 0, &table);
 	if (ACPI_FAILURE(status)) {
 		const char *msg = acpi_format_exception(status);

 		pr_err("Failed to get FADT table, %s\n", msg);
 		return -ENODEV;
 	}

 	fadt = (struct acpi_table_fadt *)table;

 	/*
 	 * Revision in table header is the FADT Major revision, and there
 	 * is a minor revision of FADT which was introduced by ACPI 5.1,
 	 * we only deal with ACPI 5.1 or newer revision to get GIC and SMP
 	 * boot protocol configuration data.
 	 */
 	if (table->revision < 5 ||
 	   (table->revision == 5 && fadt->minor_revision < 1)) {
 		pr_err(FW_BUG "Unsupported FADT revision %d.%d, should be 5.1+\n",
 		       table->revision, fadt->minor_revision);

 		if (!fadt->arm_boot_flags) {
 			ret = -EINVAL;
 			goto out;
 		}
 		pr_err("FADT has ARM boot flags set, assuming 5.1\n");
 	}

 	if (!(fadt->flags & ACPI_FADT_HW_REDUCED)) {
 		pr_err("FADT not ACPI hardware reduced compliant\n");
 		ret = -EINVAL;
 	}

 out:
 	/*
 	 * acpi_get_table() creates FADT table mapping that
 	 * should be released after parsing and before resuming boot
 	 */
 	acpi_put_table(table);
 	return ret;
 }

 /*
  * acpi_boot_table_init() called from setup_arch(), always.
  *	1. find RSDP and get its address, and then find XSDT
  *	2. extract all tables and checksums them all
  *	3. check ACPI FADT revision
  *	4. check ACPI FADT HW reduced flag
  *
  * We can parse ACPI boot-time tables such as MADT after
  * this function is called.
  *
  * On return ACPI is enabled if either:
  *
  * - ACPI tables are initialized and sanity checks passed
  * - acpi=force was passed in the command line and ACPI was not disabled
  *   explicitly through acpi=off command line parameter
  *
  * ACPI is disabled on function return otherwise
  */
 void __init acpi_boot_table_init(void)
 {
 	/*
 	 * Enable ACPI instead of device tree unless
 	 * - ACPI has been disabled explicitly (acpi=off), or
 	 * - the device tree is not empty (it has more than just a /chosen node,
 	 *   and a /hypervisor node when running on Xen)
 	 *   and ACPI has not been [force] enabled (acpi=on|force)
 	 */
 	if (param_acpi_off ||
 	    (!param_acpi_on && !param_acpi_force && !dt_is_stub()))
 		goto done;

 	/*
 	 * ACPI is disabled at this point. Enable it in order to parse
 	 * the ACPI tables and carry out sanity checks
 	 */
 	enable_acpi();

 	/*
 	 * If ACPI tables are initialized and FADT sanity checks passed,
 	 * leave ACPI enabled and carry on booting; otherwise disable ACPI
 	 * on initialization error.
 	 * If acpi=force was passed on the command line it forces ACPI
 	 * to be enabled even if its initialization failed.
 	 */
 	if (acpi_table_init() || acpi_fadt_sanity_check()) {
 		pr_err("Failed to init ACPI tables\n");
 		if (!param_acpi_force)
 			disable_acpi();
 	}

 done:
 	if (acpi_disabled) {
 		if (earlycon_acpi_spcr_enable)
 			early_init_dt_scan_chosen_stdout();
 	} else {
 #ifdef CONFIG_HIBERNATION
 		struct acpi_table_header *facs = NULL;
 		acpi_get_table(ACPI_SIG_FACS, 1, &facs);
 		if (facs) {
 			swsusp_hardware_signature =
 				((struct acpi_table_facs *)facs)->hardware_signature;
 			acpi_put_table(facs);
 		}
 #endif

 		/*
 		 * For varying privacy and security reasons, sometimes need
 		 * to completely silence the serial console output, and only
 		 * enable it when needed.
 		 * But there are many existing systems that depend on this
 		 * behaviour, use acpi=nospcr to disable console in ACPI SPCR
 		 * table as default serial console.
 		 */
 		acpi_parse_spcr(earlycon_acpi_spcr_enable,
 			!param_acpi_nospcr);
 		pr_info("Use ACPI SPCR as default console: %s\n",
 				param_acpi_nospcr ? "No" : "Yes");

 		if (IS_ENABLED(CONFIG_ACPI_BGRT))
 			acpi_table_parse(ACPI_SIG_BGRT, acpi_parse_bgrt);
 	}
 }

 static pgprot_t __acpi_get_writethrough_mem_attribute(void)
 {
 	/*
 	 * Although UEFI specifies the use of Normal Write-through for
 	 * EFI_MEMORY_WT, it is seldom used in practice and not implemented
 	 * by most (all?) CPUs. Rather than allocate a MAIR just for this
 	 * purpose, emit a warning and use Normal Non-cacheable instead.
 	 */
 	pr_warn_once("No MAIR allocation for EFI_MEMORY_WT; treating as Normal Non-cacheable\n");
 	return __pgprot(PROT_NORMAL_NC);
 }

 pgprot_t __acpi_get_mem_attribute(phys_addr_t addr)
 {
 	/*
 	 * According to "Table 8 Map: EFI memory types to AArch64 memory
 	 * types" of UEFI 2.5 section 2.3.6.1, each EFI memory type is
 	 * mapped to a corresponding MAIR attribute encoding.
 	 * The EFI memory attribute advises all possible capabilities
 	 * of a memory region.
 	 */

 	u64 attr;

 	attr = efi_mem_attributes(addr);
 	if (attr & EFI_MEMORY_WB)
 		return PAGE_KERNEL;
 	if (attr & EFI_MEMORY_WC)
 		return __pgprot(PROT_NORMAL_NC);
 	if (attr & EFI_MEMORY_WT)
 		return __acpi_get_writethrough_mem_attribute();
 	return __pgprot(PROT_DEVICE_nGnRnE);
 }

 void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size)
 {
 	efi_memory_desc_t *md, *region = NULL;
 	pgprot_t prot;

 	if (WARN_ON_ONCE(!efi_enabled(EFI_MEMMAP)))
 		return NULL;

 	for_each_efi_memory_desc(md) {
 		u64 end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);

 		if (phys < md->phys_addr || phys >= end)
 			continue;

 		if (phys + size > end) {
 			pr_warn(FW_BUG "requested region covers multiple EFI memory regions\n");
 			return NULL;
 		}
 		region = md;
 		break;
 	}

 	/*
 	 * It is fine for AML to remap regions that are not represented in the
 	 * EFI memory map at all, as it only describes normal memory, and MMIO
 	 * regions that require a virtual mapping to make them accessible to
 	 * the EFI runtime services.
 	 */
 	prot = __pgprot(PROT_DEVICE_nGnRnE);
 	if (region) {
 		switch (region->type) {
 		case EFI_LOADER_CODE:
 		case EFI_LOADER_DATA:
 		case EFI_BOOT_SERVICES_CODE:
 		case EFI_BOOT_SERVICES_DATA:
 		case EFI_CONVENTIONAL_MEMORY:
 		case EFI_PERSISTENT_MEMORY:
 			if (memblock_is_map_memory(phys) ||
 			    !memblock_is_region_memory(phys, size)) {
 				pr_warn(FW_BUG "requested region covers kernel memory @ %pa\n", &phys);
 				return NULL;
 			}
 			/*
 			 * Mapping kernel memory is permitted if the region in
 			 * question is covered by a single memblock with the
 			 * NOMAP attribute set: this enables the use of ACPI
 			 * table overrides passed via initramfs, which are
 			 * reserved in memory using arch_reserve_mem_area()
 			 * below. As this particular use case only requires
 			 * read access, fall through to the R/O mapping case.
 			 */
 			fallthrough;

 		case EFI_RUNTIME_SERVICES_CODE:
 			/*
 			 * This would be unusual, but not problematic per se,
 			 * as long as we take care not to create a writable
 			 * mapping for executable code.
 			 */
 			prot = PAGE_KERNEL_RO;
 			break;

 		case EFI_ACPI_RECLAIM_MEMORY:
 			/*
 			 * ACPI reclaim memory is used to pass firmware tables
 			 * and other data that is intended for consumption by
 			 * the OS only, which may decide it wants to reclaim
 			 * that memory and use it for something else. We never
 			 * do that, but we usually add it to the linear map
 			 * anyway, in which case we should use the existing
 			 * mapping.
 			 */
 			if (memblock_is_map_memory(phys))
 				return (void __iomem *)__phys_to_virt(phys);
 			fallthrough;

 		default:
 			if (region->attribute & EFI_MEMORY_WB)
 				prot = PAGE_KERNEL;
 			else if (region->attribute & EFI_MEMORY_WC)
 				prot = __pgprot(PROT_NORMAL_NC);
 			else if (region->attribute & EFI_MEMORY_WT)
 				prot = __acpi_get_writethrough_mem_attribute();
 		}
 	}
 	return ioremap_prot(phys, size, pgprot_val(prot));
 }

 /*
  * Claim Synchronous External Aborts as a firmware first notification.
  *
  * Used by KVM and the arch do_sea handler.
  * @regs may be NULL when called from process context.
  */
 int apei_claim_sea(struct pt_regs *regs)
 {
 	int err = -ENOENT;
 	bool return_to_irqs_enabled;
 	unsigned long current_flags;

 	if (!IS_ENABLED(CONFIG_ACPI_APEI_GHES))
 		return err;

 	current_flags = local_daif_save_flags();

 	/* current_flags isn't useful here as daif doesn't tell us about pNMI */
 	return_to_irqs_enabled = !irqs_disabled_flags(arch_local_save_flags());

 	if (regs)
 		return_to_irqs_enabled = interrupts_enabled(regs);

 	/*
 	 * SEA can interrupt SError, mask it and describe this as an NMI so
 	 * that APEI defers the handling.
 	 */
 	local_daif_restore(DAIF_ERRCTX);
 	nmi_enter();
 	err = ghes_notify_sea();
 	nmi_exit();

 	/*
 	 * APEI NMI-like notifications are deferred to irq_work. Unless
 	 * we interrupted irqs-masked code, we can do that now.
 	 */
 	if (!err) {
 		if (return_to_irqs_enabled) {
 			local_daif_restore(DAIF_PROCCTX_NOIRQ);
 			__irq_enter();
 			irq_work_run();
 			__irq_exit();
 		} else {
 			pr_warn_ratelimited("APEI work queued but not completed");
 			err = -EINPROGRESS;
 		}
 	}

 	local_daif_restore(current_flags);

 	return err;
 }

 void arch_reserve_mem_area(acpi_physical_address addr, size_t size)
 {
 	memblock_mark_nomap(addr, size);
 }

 #ifdef CONFIG_ACPI_HOTPLUG_CPU
 int acpi_map_cpu(acpi_handle handle, phys_cpuid_t physid, u32 apci_id,
 		 int *pcpu)
 {
 	/* If an error code is passed in this stub can't fix it */
 	if (*pcpu < 0) {
 		pr_warn_once("Unable to map CPU to valid ID\n");
 		return *pcpu;
 	}

 	return 0;
 }
 EXPORT_SYMBOL(acpi_map_cpu);

 int acpi_unmap_cpu(int cpu)
 {
 	return 0;
 }
 EXPORT_SYMBOL(acpi_unmap_cpu);
 #endif /* CONFIG_ACPI_HOTPLUG_CPU */
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* ARM64 Specific Low-Level ACPI Boot Support
	*
	* Copyright (C) 2013-2014, Linaro Ltd.
	* Author: Al Stone <al.stone@linaro.org>
	* Author: Graeme Gregory <graeme.gregory@linaro.org>
	* Author: Hanjun Guo <hanjun.guo@linaro.org>
	* Author: Tomasz Nowicki <tomasz.nowicki@linaro.org>
	* Author: Naresh Bhat <naresh.bhat@linaro.org>
	*/

	#define pr_fmt(fmt) "ACPI: " fmt

	#include <linux/acpi.h>
	#include <linux/arm-smccc.h>
	#include <linux/cpumask.h>
	#include <linux/efi.h>
	#include <linux/efi-bgrt.h>
	#include <linux/init.h>
	#include <linux/irq.h>
	#include <linux/irqdomain.h>
	#include <linux/irq_work.h>
	#include <linux/memblock.h>
	#include <linux/of_fdt.h>
	#include <linux/libfdt.h>
	#include <linux/smp.h>
	#include <linux/serial_core.h>
	#include <linux/suspend.h>
	#include <linux/pgtable.h>

	#include <acpi/ghes.h>
	#include <acpi/processor.h>
	#include <asm/cputype.h>
	#include <asm/cpu_ops.h>
	#include <asm/daifflags.h>
	#include <asm/smp_plat.h>

	int acpi_noirq = 1; /* skip ACPI IRQ initialization */
	int acpi_disabled = 1;
	EXPORT_SYMBOL(acpi_disabled);

	int acpi_pci_disabled = 1; /* skip ACPI PCI scan and IRQ initialization */
	EXPORT_SYMBOL(acpi_pci_disabled);

	static bool param_acpi_off __initdata;
	static bool param_acpi_on __initdata;
	static bool param_acpi_force __initdata;
	static bool param_acpi_nospcr __initdata;

	static int __init parse_acpi(char *arg)
	{
	if (!arg)
	return -EINVAL;

	/* "acpi=off" disables both ACPI table parsing and interpreter */
	if (strcmp(arg, "off") == 0)
	param_acpi_off = true;
	else if (strcmp(arg, "on") == 0) /* prefer ACPI over DT */
	param_acpi_on = true;
	else if (strcmp(arg, "force") == 0) /* force ACPI to be enabled */
	param_acpi_force = true;
	else if (strcmp(arg, "nospcr") == 0) /* disable SPCR as default console */
	param_acpi_nospcr = true;
	else
	return -EINVAL; /* Core will print when we return error */

	return 0;
	}
	early_param("acpi", parse_acpi);

	static bool __init dt_is_stub(void)
	{
	int node;

	fdt_for_each_subnode(node, initial_boot_params, 0) {
	const char *name = fdt_get_name(initial_boot_params, node, NULL);
	if (strcmp(name, "chosen") == 0)
	continue;
	if (strcmp(name, "hypervisor") == 0 &&
	of_flat_dt_is_compatible(node, "xen,xen"))
	continue;

	return false;
	}

	return true;
	}

	/*
	* __acpi_map_table() will be called before page_init(), so early_ioremap()
	* or early_memremap() should be called here to for ACPI table mapping.
	*/
	void __init __iomem *__acpi_map_table(unsigned long phys, unsigned long size)
	{
	if (!size)
	return NULL;

	return early_memremap(phys, size);
	}

	void __init __acpi_unmap_table(void __iomem *map, unsigned long size)
	{
	if (!map \|\| !size)
	return;

	early_memunmap(map, size);
	}

	bool __init acpi_psci_present(void)
	{
	return acpi_gbl_FADT.arm_boot_flags & ACPI_FADT_PSCI_COMPLIANT;
	}

	/* Whether HVC must be used instead of SMC as the PSCI conduit */
	bool acpi_psci_use_hvc(void)
	{
	return acpi_gbl_FADT.arm_boot_flags & ACPI_FADT_PSCI_USE_HVC;
	}

	/*
	* acpi_fadt_sanity_check() - Check FADT presence and carry out sanity
	* checks on it
	*
	* Return 0 on success, <0 on failure
	*/
	static int __init acpi_fadt_sanity_check(void)
	{
	struct acpi_table_header *table;
	struct acpi_table_fadt *fadt;
	acpi_status status;
	int ret = 0;

	/*
	* FADT is required on arm64; retrieve it to check its presence
	* and carry out revision and ACPI HW reduced compliancy tests
	*/
	status = acpi_get_table(ACPI_SIG_FADT, 0, &table);
	if (ACPI_FAILURE(status)) {
	const char *msg = acpi_format_exception(status);

	pr_err("Failed to get FADT table, %s\n", msg);
	return -ENODEV;
	}

	fadt = (struct acpi_table_fadt *)table;

	/*
	* Revision in table header is the FADT Major revision, and there
	* is a minor revision of FADT which was introduced by ACPI 5.1,
	* we only deal with ACPI 5.1 or newer revision to get GIC and SMP
	* boot protocol configuration data.
	*/
	if (table->revision < 5 \|\|
	(table->revision == 5 && fadt->minor_revision < 1)) {
	pr_err(FW_BUG "Unsupported FADT revision %d.%d, should be 5.1+\n",
	table->revision, fadt->minor_revision);

	if (!fadt->arm_boot_flags) {
	ret = -EINVAL;
	goto out;
	}
	pr_err("FADT has ARM boot flags set, assuming 5.1\n");
	}

	if (!(fadt->flags & ACPI_FADT_HW_REDUCED)) {
	pr_err("FADT not ACPI hardware reduced compliant\n");
	ret = -EINVAL;
	}

	out:
	/*
	* acpi_get_table() creates FADT table mapping that
	* should be released after parsing and before resuming boot
	*/
	acpi_put_table(table);
	return ret;
	}

	/*
	* acpi_boot_table_init() called from setup_arch(), always.
	* 1. find RSDP and get its address, and then find XSDT
	* 2. extract all tables and checksums them all
	* 3. check ACPI FADT revision
	* 4. check ACPI FADT HW reduced flag
	*
	* We can parse ACPI boot-time tables such as MADT after
	* this function is called.
	*
	* On return ACPI is enabled if either:
	*
	* - ACPI tables are initialized and sanity checks passed
	* - acpi=force was passed in the command line and ACPI was not disabled
	* explicitly through acpi=off command line parameter
	*
	* ACPI is disabled on function return otherwise
	*/
	void __init acpi_boot_table_init(void)
	{
	/*
	* Enable ACPI instead of device tree unless
	* - ACPI has been disabled explicitly (acpi=off), or
	* - the device tree is not empty (it has more than just a /chosen node,
	* and a /hypervisor node when running on Xen)
	* and ACPI has not been [force] enabled (acpi=on\|force)
	*/
	if (param_acpi_off \|\|
	(!param_acpi_on && !param_acpi_force && !dt_is_stub()))
	goto done;

	/*
	* ACPI is disabled at this point. Enable it in order to parse
	* the ACPI tables and carry out sanity checks
	*/
	enable_acpi();

	/*
	* If ACPI tables are initialized and FADT sanity checks passed,
	* leave ACPI enabled and carry on booting; otherwise disable ACPI
	* on initialization error.
	* If acpi=force was passed on the command line it forces ACPI
	* to be enabled even if its initialization failed.
	*/
	if (acpi_table_init() \|\| acpi_fadt_sanity_check()) {
	pr_err("Failed to init ACPI tables\n");
	if (!param_acpi_force)
	disable_acpi();
	}

	done:
	if (acpi_disabled) {
	if (earlycon_acpi_spcr_enable)
	early_init_dt_scan_chosen_stdout();
	} else {
	#ifdef CONFIG_HIBERNATION
	struct acpi_table_header *facs = NULL;
	acpi_get_table(ACPI_SIG_FACS, 1, &facs);
	if (facs) {
	swsusp_hardware_signature =
	((struct acpi_table_facs *)facs)->hardware_signature;
	acpi_put_table(facs);
	}
	#endif

	/*
	* For varying privacy and security reasons, sometimes need
	* to completely silence the serial console output, and only
	* enable it when needed.
	* But there are many existing systems that depend on this
	* behaviour, use acpi=nospcr to disable console in ACPI SPCR
	* table as default serial console.
	*/
	acpi_parse_spcr(earlycon_acpi_spcr_enable,
	!param_acpi_nospcr);
	pr_info("Use ACPI SPCR as default console: %s\n",
	param_acpi_nospcr ? "No" : "Yes");

	if (IS_ENABLED(CONFIG_ACPI_BGRT))
	acpi_table_parse(ACPI_SIG_BGRT, acpi_parse_bgrt);
	}
	}

	static pgprot_t __acpi_get_writethrough_mem_attribute(void)
	{
	/*
	* Although UEFI specifies the use of Normal Write-through for
	* EFI_MEMORY_WT, it is seldom used in practice and not implemented
	* by most (all?) CPUs. Rather than allocate a MAIR just for this
	* purpose, emit a warning and use Normal Non-cacheable instead.
	*/
	pr_warn_once("No MAIR allocation for EFI_MEMORY_WT; treating as Normal Non-cacheable\n");
	return __pgprot(PROT_NORMAL_NC);
	}

	pgprot_t __acpi_get_mem_attribute(phys_addr_t addr)
	{
	/*
	* According to "Table 8 Map: EFI memory types to AArch64 memory
	* types" of UEFI 2.5 section 2.3.6.1, each EFI memory type is
	* mapped to a corresponding MAIR attribute encoding.
	* The EFI memory attribute advises all possible capabilities
	* of a memory region.
	*/

	u64 attr;

	attr = efi_mem_attributes(addr);
	if (attr & EFI_MEMORY_WB)
	return PAGE_KERNEL;
	if (attr & EFI_MEMORY_WC)
	return __pgprot(PROT_NORMAL_NC);
	if (attr & EFI_MEMORY_WT)
	return __acpi_get_writethrough_mem_attribute();
	return __pgprot(PROT_DEVICE_nGnRnE);
	}

	void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size)
	{
	efi_memory_desc_t md, region = NULL;
	pgprot_t prot;

	if (WARN_ON_ONCE(!efi_enabled(EFI_MEMMAP)))
	return NULL;

	for_each_efi_memory_desc(md) {
	u64 end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);

	if (phys < md->phys_addr \|\| phys >= end)
	continue;

	if (phys + size > end) {
	pr_warn(FW_BUG "requested region covers multiple EFI memory regions\n");
	return NULL;
	}
	region = md;
	break;
	}

	/*
	* It is fine for AML to remap regions that are not represented in the
	* EFI memory map at all, as it only describes normal memory, and MMIO
	* regions that require a virtual mapping to make them accessible to
	* the EFI runtime services.
	*/
	prot = __pgprot(PROT_DEVICE_nGnRnE);
	if (region) {
	switch (region->type) {
	case EFI_LOADER_CODE:
	case EFI_LOADER_DATA:
	case EFI_BOOT_SERVICES_CODE:
	case EFI_BOOT_SERVICES_DATA:
	case EFI_CONVENTIONAL_MEMORY:
	case EFI_PERSISTENT_MEMORY:
	if (memblock_is_map_memory(phys) \|\|
	!memblock_is_region_memory(phys, size)) {
	pr_warn(FW_BUG "requested region covers kernel memory @ %pa\n", &phys);
	return NULL;
	}
	/*
	* Mapping kernel memory is permitted if the region in
	* question is covered by a single memblock with the
	* NOMAP attribute set: this enables the use of ACPI
	* table overrides passed via initramfs, which are
	* reserved in memory using arch_reserve_mem_area()
	* below. As this particular use case only requires
	* read access, fall through to the R/O mapping case.
	*/
	fallthrough;

	case EFI_RUNTIME_SERVICES_CODE:
	/*
	* This would be unusual, but not problematic per se,
	* as long as we take care not to create a writable
	* mapping for executable code.
	*/
	prot = PAGE_KERNEL_RO;
	break;

	case EFI_ACPI_RECLAIM_MEMORY:
	/*
	* ACPI reclaim memory is used to pass firmware tables
	* and other data that is intended for consumption by
	* the OS only, which may decide it wants to reclaim
	* that memory and use it for something else. We never
	* do that, but we usually add it to the linear map
	* anyway, in which case we should use the existing
	* mapping.
	*/
	if (memblock_is_map_memory(phys))
	return (void __iomem *)__phys_to_virt(phys);
	fallthrough;

	default:
	if (region->attribute & EFI_MEMORY_WB)
	prot = PAGE_KERNEL;
	else if (region->attribute & EFI_MEMORY_WC)
	prot = __pgprot(PROT_NORMAL_NC);
	else if (region->attribute & EFI_MEMORY_WT)
	prot = __acpi_get_writethrough_mem_attribute();
	}
	}
	return ioremap_prot(phys, size, pgprot_val(prot));
	}

	/*
	* Claim Synchronous External Aborts as a firmware first notification.
	*
	* Used by KVM and the arch do_sea handler.
	* @regs may be NULL when called from process context.
	*/
	int apei_claim_sea(struct pt_regs *regs)
	{
	int err = -ENOENT;
	bool return_to_irqs_enabled;
	unsigned long current_flags;

	if (!IS_ENABLED(CONFIG_ACPI_APEI_GHES))
	return err;

	current_flags = local_daif_save_flags();

	/* current_flags isn't useful here as daif doesn't tell us about pNMI */
	return_to_irqs_enabled = !irqs_disabled_flags(arch_local_save_flags());

	if (regs)
	return_to_irqs_enabled = interrupts_enabled(regs);

	/*
	* SEA can interrupt SError, mask it and describe this as an NMI so
	* that APEI defers the handling.
	*/
	local_daif_restore(DAIF_ERRCTX);
	nmi_enter();
	err = ghes_notify_sea();
	nmi_exit();

	/*
	* APEI NMI-like notifications are deferred to irq_work. Unless
	* we interrupted irqs-masked code, we can do that now.
	*/
	if (!err) {
	if (return_to_irqs_enabled) {
	local_daif_restore(DAIF_PROCCTX_NOIRQ);
	__irq_enter();
	irq_work_run();
	__irq_exit();
	} else {
	pr_warn_ratelimited("APEI work queued but not completed");
	err = -EINPROGRESS;
	}
	}

	local_daif_restore(current_flags);

	return err;
	}

	void arch_reserve_mem_area(acpi_physical_address addr, size_t size)
	{
	memblock_mark_nomap(addr, size);
	}

	#ifdef CONFIG_ACPI_HOTPLUG_CPU
	int acpi_map_cpu(acpi_handle handle, phys_cpuid_t physid, u32 apci_id,
	int *pcpu)
	{
	/* If an error code is passed in this stub can't fix it */
	if (*pcpu < 0) {
	pr_warn_once("Unable to map CPU to valid ID\n");
	return *pcpu;
	}

	return 0;
	}
	EXPORT_SYMBOL(acpi_map_cpu);

	int acpi_unmap_cpu(int cpu)
	{
	return 0;
	}
	EXPORT_SYMBOL(acpi_unmap_cpu);
	#endif /* CONFIG_ACPI_HOTPLUG_CPU */