// 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/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/pgtable.h>

#include <acpi/ghes.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 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
                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 {
                acpi_parse_spcr(earlycon_acpi_spcr_enable, true);
                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(phys, size, 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);
}