/*
 * Copyright (c) 2000-2017, 2024 Apple Inc. All rights reserved.
 *
 *    arm platform expert initialization.
 */
#include <sys/types.h>
#include <sys/kdebug.h>
#include <mach/vm_param.h>
#include <pexpert/protos.h>
#include <pexpert/pexpert.h>
#include <pexpert/boot.h>
#include <pexpert/device_tree.h>
#include <pexpert/pe_images.h>
#include <kern/sched_prim.h>
#include <kern/socd_client.h>
#include <machine/atomic.h>
#include <machine/machine_routines.h>
#include <arm/caches_internal.h>
#include <kern/debug.h>
#include <libkern/section_keywords.h>
#include <os/overflow.h>

#include <pexpert/arm64/board_config.h>

#if CONFIG_SPTM
#include <arm64/sptm/sptm.h>
#endif

/* extern references */
extern void     pe_identify_machine(boot_args *bootArgs);

/* static references */
static void     pe_prepare_images(void);

/* private globals */
SECURITY_READ_ONLY_LATE(PE_state_t) PE_state;
TUNABLE_DT(uint32_t, PE_esdm_fuses, "/chosen", "esdm-fuses", "", 0, TUNABLE_DT_NONE);
TUNABLE_DT(uint32_t, PE_vmm_present, "/defaults", "vmm-present", "", 0, TUNABLE_DT_NONE);

#define FW_VERS_LEN 128

char iBoot_version[FW_VERS_LEN];
#if defined(TARGET_OS_OSX) && defined(__arm64__)
char iBoot_Stage_2_version[FW_VERS_LEN];
#endif /* defined(TARGET_OS_OSX) && defined(__arm64__) */

/*
 * This variable is only modified once, when the BSP starts executing. We put it in __DATA_CONST
 * as page protections on kernel text early in startup are read-write. The kernel is
 * locked down later in start-up, said mappings become RO and thus this
 * variable becomes immutable.
 *
 * See osfmk/arm/arm_vm_init.c for more information.
 */
SECURITY_READ_ONLY_LATE(volatile uint32_t) debug_enabled = FALSE;

/*
 * This variable indicates the page protection security policy used by the system.
 * It is intended mostly for debugging purposes.
 */
SECURITY_READ_ONLY_LATE(ml_page_protection_t) page_protection_type;

uint8_t         gPlatformECID[8];
uint32_t        gPlatformMemoryID;
#if defined(XNU_TARGET_OS_XR)
uint32_t        gPlatformChipRole = UINT32_MAX;
#endif /* not XNU_TARGET_OS_XR */
static boolean_t vc_progress_initialized = FALSE;
uint64_t    last_hwaccess_thread = 0;
uint8_t last_hwaccess_type = 0;
uint8_t last_hwaccess_size = 0;
uint64_t last_hwaccess_paddr = 0;
char     gTargetTypeBuffer[16];
char     gUniqueDeviceTargetTypeBuffer[16];   /* Holds "sub-product-type" from product entry */
char     gUniqueDeviceModelTypeBuffer[32];    /* Holds "unique-model" from product entry */

/* Clock Frequency Info */
clock_frequency_info_t gPEClockFrequencyInfo;

vm_offset_t gPanicBase = 0;
unsigned int gPanicSize;
struct embedded_panic_header *panic_info = NULL;

#if (DEVELOPMENT || DEBUG) && defined(XNU_TARGET_OS_BRIDGE)
/*
 * On DEVELOPMENT bridgeOS, we map the x86 panic region
 * so we can include this data in bridgeOS corefiles
 */
uint64_t macos_panic_base = 0;
unsigned int macos_panic_size = 0;

struct macos_panic_header *mac_panic_header = NULL;
#endif

/* Maximum size of panic log excluding headers, in bytes */
static unsigned int panic_text_len;

/* Whether a console is standing by for panic logging */
static boolean_t panic_console_available = FALSE;

/* socd trace ram attributes */
static SECURITY_READ_ONLY_LATE(vm_offset_t) socd_trace_ram_base = 0;
static SECURITY_READ_ONLY_LATE(vm_size_t) socd_trace_ram_size = 0;

extern uint32_t crc32(uint32_t crc, const void *buf, size_t size);

void PE_slide_devicetree(vm_offset_t);

static void
pe_init_fill_buffer_from_property(DTEntry entry, const char *property_name, char *buffer, size_t buffer_size)
{
	void const *prop;
	unsigned int size;

	buffer[0] = '\0';  // Initialize buffer to empty string

	if (kSuccess == SecureDTGetProperty(entry, property_name, &prop, &size)) {
		if (size > buffer_size) {
			size = buffer_size;
		}
		if (size > 0) {
			bcopy(prop, buffer, size);
			buffer[size - 1] = '\0';
		}
	}
}

static void
check_for_panic_log(void)
{
#ifdef PLATFORM_PANIC_LOG_PADDR
	gPanicBase = ml_io_map_wcomb(PLATFORM_PANIC_LOG_PADDR, PLATFORM_PANIC_LOG_SIZE);
	panic_text_len = PLATFORM_PANIC_LOG_SIZE - sizeof(struct embedded_panic_header);
	gPanicSize = PLATFORM_PANIC_LOG_SIZE;
#else
	DTEntry entry, chosen;
	unsigned int size;
	uintptr_t const *reg_prop;
	uint32_t const *panic_region_length;

	/*
	 * DT properties for the panic region are populated by UpdateDeviceTree() in iBoot:
	 *
	 * chosen {
	 *   embedded-panic-log-size = <0x00080000>;
	 *   [a bunch of other stuff]
	 * };
	 *
	 * pram {
	 *   reg = <0x00000008_fbc48000 0x00000000_000b4000>;
	 * };
	 *
	 * reg[0] is the physical address
	 * reg[1] is the size of iBoot's kMemoryRegion_Panic (not used)
	 * embedded-panic-log-size is the maximum amount of data to store in the buffer
	 */
	if (kSuccess != SecureDTLookupEntry(0, "pram", &entry)) {
		return;
	}

	if (kSuccess != SecureDTGetProperty(entry, "reg", (void const **)&reg_prop, &size)) {
		return;
	}

	if (kSuccess != SecureDTLookupEntry(0, "/chosen", &chosen)) {
		return;
	}

	if (kSuccess != SecureDTGetProperty(chosen, "embedded-panic-log-size", (void const **) &panic_region_length, &size)) {
		return;
	}

	gPanicBase = ml_io_map_wcomb(reg_prop[0], panic_region_length[0]);

	/* Deduct the size of the panic header from the panic region size */
	panic_text_len = panic_region_length[0] - sizeof(struct embedded_panic_header);
	gPanicSize = panic_region_length[0];

#if DEVELOPMENT && defined(XNU_TARGET_OS_BRIDGE)
	if (PE_consistent_debug_enabled()) {
		uint64_t macos_panic_physbase = 0;
		uint64_t macos_panic_physlen = 0;
		/* Populate the macOS panic region data if it's present in consistent debug */
		if (PE_consistent_debug_lookup_entry(kDbgIdMacOSPanicRegion, &macos_panic_physbase, &macos_panic_physlen)) {
			macos_panic_base = ml_io_map_with_prot(macos_panic_physbase, macos_panic_physlen, VM_PROT_READ);
			mac_panic_header = (struct macos_panic_header *) ((void *) macos_panic_base);
			macos_panic_size = macos_panic_physlen;
		}
	}
#endif /* DEVELOPMENT && defined(XNU_TARGET_OS_BRIDGE) */

#endif
	panic_info = (struct embedded_panic_header *)gPanicBase;

	/* Check if a shared memory console is running in the panic buffer */
	if (panic_info->eph_magic == 'SHMC') {
		panic_console_available = TRUE;
		return;
	}

	/* Check if there's a boot profile in the panic buffer */
	if (panic_info->eph_magic == 'BTRC') {
		return;
	}

	/*
	 * Check to see if a panic (FUNK) is in VRAM from the last time
	 */
	if (panic_info->eph_magic == EMBEDDED_PANIC_MAGIC) {
		printf("iBoot didn't extract panic log from previous session crash, this is bad\n");
	}

	/* Clear panic region */
	CleanPoC_DcacheRegion_Force(gPanicBase, gPanicSize);
	bzero((void *)gPanicBase, gPanicSize);
}

int
PE_initialize_console(PE_Video * info, int op)
{
	static int last_console = -1;

	if (info && (info != &PE_state.video)) {
		info->v_scale = PE_state.video.v_scale;
	}

	switch (op) {
	case kPEDisableScreen:
		initialize_screen(info, op);
		last_console = switch_to_serial_console();
		kprintf("kPEDisableScreen %d\n", last_console);
		break;

	case kPEEnableScreen:
		initialize_screen(info, op);
		if (info) {
			PE_state.video = *info;
		}
		kprintf("kPEEnableScreen %d\n", last_console);
		if (last_console != -1) {
			switch_to_old_console(last_console);
		}
		break;

	case kPEReleaseScreen:
		/*
		 * we don't show the progress indicator on boot, but want to
		 * show it afterwards.
		 */
		if (!vc_progress_initialized) {
			default_progress.dx = 0;
			default_progress.dy = 0;
			vc_progress_initialize(&default_progress,
			    default_progress_data1x,
			    default_progress_data2x,
			    default_progress_data3x,
			    (unsigned char *) appleClut8);
			vc_progress_initialized = TRUE;
		}
		initialize_screen(info, op);
		break;

	default:
		initialize_screen(info, op);
		break;
	}

	return 0;
}

void
PE_init_iokit(void)
{
	DTEntry         entry;
	unsigned int    size, scale;
	unsigned long   display_size;
	void const * const *map;
	unsigned int    show_progress;
	int             *delta, image_size, flip;
	uint32_t        start_time_value = 0;
	uint32_t        debug_wait_start_value = 0;
	uint32_t        load_kernel_start_value = 0;
	uint32_t        populate_registry_time_value = 0;

	PE_init_printf(TRUE);

	printf("iBoot version: %s\n", iBoot_version);
#if defined(TARGET_OS_OSX) && defined(__arm64__)
	printf("iBoot Stage 2 version: %s\n", iBoot_Stage_2_version);
#endif /* defined(TARGET_OS_OSX) && defined(__arm64__) */

	if (kSuccess == SecureDTLookupEntry(0, "/chosen/memory-map", &entry)) {
		boot_progress_element const *bootPict;

		if (kSuccess == SecureDTGetProperty(entry, "BootCLUT", (void const **) &map, &size)) {
			bcopy(map[0], appleClut8, sizeof(appleClut8));
		}

		if (kSuccess == SecureDTGetProperty(entry, "Pict-FailedBoot", (void const **) &map, &size)) {
			bootPict = (boot_progress_element const *) map[0];
			default_noroot.width = bootPict->width;
			default_noroot.height = bootPict->height;
			default_noroot.dx = 0;
			default_noroot.dy = bootPict->yOffset;
			default_noroot_data = &bootPict->data[0];
		}
	}

	pe_prepare_images();

	scale = PE_state.video.v_scale;
	flip = 1;

#if defined(XNU_TARGET_OS_OSX)
	int notused;
	show_progress = TRUE;
	if (PE_parse_boot_argn("-restore", &notused, sizeof(notused))) {
		show_progress = FALSE;
	}
	if (PE_parse_boot_argn("-noprogress", &notused, sizeof(notused))) {
		show_progress = FALSE;
	}
	if (PE_parse_boot_argn("-noprogressonce", &notused, sizeof(notused))) {
		show_progress = FALSE;
	}
#else
	show_progress = FALSE;
	PE_parse_boot_argn("-progress", &show_progress, sizeof(show_progress));
#endif /* XNU_TARGET_OS_OSX */
	if (show_progress) {
		/* Rotation: 0:normal, 1:right 90, 2:left 180, 3:left 90 */
		switch (PE_state.video.v_rotate) {
		case 2:
			flip = -1;
			OS_FALLTHROUGH;
		case 0:
			display_size = PE_state.video.v_height;
			image_size = default_progress.height;
			delta = &default_progress.dy;
			break;
		case 1:
			flip = -1;
			OS_FALLTHROUGH;
		case 3:
		default:
			display_size = PE_state.video.v_width;
			image_size = default_progress.width;
			delta = &default_progress.dx;
		}
		assert(*delta >= 0);
		while (((unsigned)(*delta + image_size)) >= (display_size / 2)) {
			*delta -= 50 * scale;
			assert(*delta >= 0);
		}
		*delta *= flip;

		/* Check for DT-defined progress y delta */
		PE_get_default("progress-dy", &default_progress.dy, sizeof(default_progress.dy));

		vc_progress_initialize(&default_progress,
		    default_progress_data1x,
		    default_progress_data2x,
		    default_progress_data3x,
		    (unsigned char *) appleClut8);
		vc_progress_initialized = TRUE;
	}

	if (kdebug_enable && kdebug_debugid_enabled(IOKDBG_CODE(DBG_BOOTER, 0))) {
		/* Trace iBoot-provided timing information. */
		if (kSuccess == SecureDTLookupEntry(0, "/chosen/iBoot", &entry)) {
			uint32_t const * value_ptr;

			if (kSuccess == SecureDTGetProperty(entry, "start-time", (void const **)&value_ptr, &size)) {
				if (size == sizeof(start_time_value)) {
					start_time_value = *value_ptr;
				}
			}

			if (kSuccess == SecureDTGetProperty(entry, "debug-wait-start", (void const **)&value_ptr, &size)) {
				if (size == sizeof(debug_wait_start_value)) {
					debug_wait_start_value = *value_ptr;
				}
			}

			if (kSuccess == SecureDTGetProperty(entry, "load-kernel-start", (void const **)&value_ptr, &size)) {
				if (size == sizeof(load_kernel_start_value)) {
					load_kernel_start_value = *value_ptr;
				}
			}

			if (kSuccess == SecureDTGetProperty(entry, "populate-registry-time", (void const **)&value_ptr, &size)) {
				if (size == sizeof(populate_registry_time_value)) {
					populate_registry_time_value = *value_ptr;
				}
			}
		}

		KDBG_RELEASE(IOKDBG_CODE(DBG_BOOTER, 0), start_time_value, debug_wait_start_value, load_kernel_start_value, populate_registry_time_value);
#if CONFIG_SPTM
		KDBG_RELEASE(IOKDBG_CODE(DBG_BOOTER, 1), SPTMArgs->timestamp_sk_bootstrap, SPTMArgs->timestamp_xnu_bootstrap, SPTMArgs->timestamp_txm_bootstrap);
#endif
	}

	InitIOKit(PE_state.deviceTreeHead);
	ConfigureIOKit();
}

void
PE_lockdown_iokit(void)
{
	/*
	 * On arm/arm64 platforms, and especially those that employ KTRR/CTRR,
	 * machine_lockdown() is treated as a hard security checkpoint, such that
	 * code which executes prior to lockdown must be minimized and limited only to
	 * trusted parts of the kernel and specially-entitled kexts.  We therefore
	 * cannot start the general-purpose IOKit matching process until after lockdown,
	 * as it may involve execution of untrusted/non-entitled kext code.
	 * Furthermore, such kext code may process attacker controlled data (e.g.
	 * network packets), which dramatically increases the potential attack surface
	 * against a kernel which has not yet enabled the full set of available
	 * hardware protections.
	 */
	zalloc_iokit_lockdown();
	StartIOKitMatching();
}

void
PE_slide_devicetree(vm_offset_t slide)
{
	assert(PE_state.initialized);
	PE_state.deviceTreeHead = (void *)((uintptr_t)PE_state.deviceTreeHead + slide);
	SecureDTInit(PE_state.deviceTreeHead, PE_state.deviceTreeSize);
}

void
PE_init_platform(boolean_t vm_initialized, void *args)
{
	DTEntry         entry;
	unsigned int    size;
	void * const    *prop;
	boot_args      *boot_args_ptr = (boot_args *) args;

	if (PE_state.initialized == FALSE) {
		page_protection_type = ml_page_protection_type();
		PE_state.initialized = TRUE;
		PE_state.bootArgs = boot_args_ptr;
		PE_state.deviceTreeHead = boot_args_ptr->deviceTreeP;
		PE_state.deviceTreeSize = boot_args_ptr->deviceTreeLength;
		PE_state.video.v_baseAddr = boot_args_ptr->Video.v_baseAddr;
		PE_state.video.v_rowBytes = boot_args_ptr->Video.v_rowBytes;
		PE_state.video.v_width = boot_args_ptr->Video.v_width;
		PE_state.video.v_height = boot_args_ptr->Video.v_height;
		PE_state.video.v_depth = (boot_args_ptr->Video.v_depth >> kBootVideoDepthDepthShift) & kBootVideoDepthMask;
		PE_state.video.v_rotate = (
			((boot_args_ptr->Video.v_depth >> kBootVideoDepthRotateShift) & kBootVideoDepthMask) +    // rotation
			((boot_args_ptr->Video.v_depth >> kBootVideoDepthBootRotateShift)  & kBootVideoDepthMask) // add extra boot rotation
			) % 4;
		PE_state.video.v_scale = ((boot_args_ptr->Video.v_depth >> kBootVideoDepthScaleShift) & kBootVideoDepthMask) + 1;
		PE_state.video.v_display = boot_args_ptr->Video.v_display;
		strlcpy(PE_state.video.v_pixelFormat, "BBBBBBBBGGGGGGGGRRRRRRRR", sizeof(PE_state.video.v_pixelFormat));
	}
	if (!vm_initialized) {
		/*
		 * Setup the Device Tree routines
		 * so the console can be found and the right I/O space
		 * can be used..
		 */
		SecureDTInit(PE_state.deviceTreeHead, PE_state.deviceTreeSize);
		pe_identify_machine(boot_args_ptr);
	} else {
		pe_arm_init_interrupts(args);
	}

	if (!vm_initialized) {
		if (kSuccess == (SecureDTFindEntry("name", "device-tree", &entry))) {
			pe_init_fill_buffer_from_property(entry, "target-type", gTargetTypeBuffer, sizeof(gTargetTypeBuffer));
		}
		if (kSuccess == (SecureDTFindEntry("name", "product", &entry))) {
			pe_init_fill_buffer_from_property(entry, "unique-model", gUniqueDeviceTargetTypeBuffer, sizeof(gUniqueDeviceTargetTypeBuffer));
			pe_init_fill_buffer_from_property(entry, "sub-product-type", gUniqueDeviceModelTypeBuffer, sizeof(gUniqueDeviceModelTypeBuffer));
		}
		if (kSuccess == SecureDTLookupEntry(NULL, "/chosen", &entry)) {
			if (kSuccess == SecureDTGetProperty(entry, "debug-enabled",
			    (void const **) &prop, &size)) {
				/*
				 * We purposefully modify a constified variable as
				 * it will get locked down by a trusted monitor or
				 * via page table mappings. We don't want people easily
				 * modifying this variable...
				 */
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wcast-qual"
				boolean_t *modify_debug_enabled = (boolean_t *) &debug_enabled;
				if (size > sizeof(uint32_t)) {
					size = sizeof(uint32_t);
				}
				bcopy(prop, modify_debug_enabled, size);
#pragma clang diagnostic pop
			}
			if (kSuccess == SecureDTGetProperty(entry, "firmware-version", (void const **) &prop, &size)) {
				if (size > sizeof(iBoot_version)) {
					size = sizeof(iBoot_version);
				}
				bcopy(prop, iBoot_version, size);
				iBoot_version[size - 1] = '\0';
			}
#if defined(TARGET_OS_OSX) && defined(__arm64__)
			if (kSuccess == SecureDTGetProperty(entry, "system-firmware-version", (void const **) &prop, &size)) {
				if (size > sizeof(iBoot_Stage_2_version)) {
					size = sizeof(iBoot_Stage_2_version);
				}
				bcopy(prop, iBoot_Stage_2_version, size);
				iBoot_Stage_2_version[size - 1] = '\0';
			}
#endif /* defined(TARGET_OS_OSX) && defined(__arm64__) */
			if (kSuccess == SecureDTGetProperty(entry, "unique-chip-id",
			    (void const **) &prop, &size)) {
				if (size > sizeof(gPlatformECID)) {
					size = sizeof(gPlatformECID);
				}
				bcopy(prop, gPlatformECID, size);
			}
			if (kSuccess == SecureDTGetProperty(entry, "dram-vendor-id",
			    (void const **) &prop, &size)) {
				if (size > sizeof(gPlatformMemoryID)) {
					size = sizeof(gPlatformMemoryID);
				}
				bcopy(prop, &gPlatformMemoryID, size);
			}
		}
#if defined(XNU_TARGET_OS_XR)
		if (kSuccess == SecureDTLookupEntry(NULL, "/product", &entry)) {
			if (kSuccess == SecureDTGetProperty(entry, "chip-role",
			    (void const **) &prop, &size)) {
				if (size > sizeof(gPlatformChipRole)) {
					size = sizeof(gPlatformChipRole);
				}
				bcopy(prop, &gPlatformChipRole, size);
			}
		}
#endif /* not XNU_TARGET_OS_XR */
		pe_init_debug();
	}
}

void
PE_create_console(void)
{
	/*
	 * Check the head of VRAM for a panic log saved on last panic.
	 * Do this before the VRAM is trashed.
	 */
	check_for_panic_log();

	if (PE_state.video.v_display) {
		PE_initialize_console(&PE_state.video, kPEGraphicsMode);
	} else {
		PE_initialize_console(&PE_state.video, kPETextMode);
	}
}

int
PE_current_console(PE_Video * info)
{
	*info = PE_state.video;
	return 0;
}

void
PE_display_icon(__unused unsigned int flags, __unused const char *name)
{
	if (default_noroot_data) {
		vc_display_icon(&default_noroot, default_noroot_data);
	}
}

extern          boolean_t
PE_get_hotkey(__unused unsigned char key)
{
	return FALSE;
}

static timebase_callback_func gTimebaseCallback;

void
PE_register_timebase_callback(timebase_callback_func callback)
{
	gTimebaseCallback = callback;

	PE_call_timebase_callback();
}

void
PE_call_timebase_callback(void)
{
	struct timebase_freq_t timebase_freq;

	timebase_freq.timebase_num = gPEClockFrequencyInfo.timebase_frequency_hz;
	timebase_freq.timebase_den = 1;

	if (gTimebaseCallback) {
		gTimebaseCallback(&timebase_freq);
	}
}

/*
 * The default PE_poll_input handler.
 */
int
PE_stub_poll_input(__unused unsigned int options, char *c)
{
	*c = (char)uart_getc();
	return 0; /* 0 for success, 1 for unsupported */
}

/*
 * This routine will return 1 if you are running on a device with a variant
 * of iBoot that allows debugging. This is typically not the case on production
 * fused parts (even when running development variants of iBoot).
 *
 * The routine takes an optional argument of the flags passed to debug="" so
 * kexts don't have to parse the boot arg themselves.
 */
uint32_t
PE_i_can_has_debugger(uint32_t *debug_flags)
{
	if (debug_flags) {
#if DEVELOPMENT || DEBUG
		assert(startup_phase >= STARTUP_SUB_TUNABLES);
#endif
		if (debug_enabled) {
			*debug_flags = debug_boot_arg;
		} else {
			*debug_flags = 0;
		}
	}
	return debug_enabled;
}

/*
 * This routine returns TRUE if the device is configured
 * with panic debugging enabled.
 */
boolean_t
PE_panic_debugging_enabled()
{
	return panicDebugging;
}

void
PE_update_panic_crc(unsigned char *buf, unsigned int *size)
{
	if (!panic_info || !size) {
		return;
	}

	if (!buf) {
		*size = panic_text_len;
		return;
	}

	if (*size == 0) {
		return;
	}

	*size = *size > panic_text_len ? panic_text_len : *size;
	if (panic_info->eph_magic != EMBEDDED_PANIC_MAGIC) {
		// rdar://88696402 (PanicTest: test case for MAGIC check in PE_update_panic_crc)
		printf("Error!! Current Magic 0x%X, expected value 0x%x\n", panic_info->eph_magic, EMBEDDED_PANIC_MAGIC);
	}

	/* CRC everything after the CRC itself - starting with the panic header version */
	panic_info->eph_crc = crc32(0L, &panic_info->eph_version, (panic_text_len +
	    sizeof(struct embedded_panic_header) - offsetof(struct embedded_panic_header, eph_version)));
}

uint32_t
PE_get_offset_into_panic_region(char *location)
{
	assert(gPanicBase != 0);
	assert(location >= (char *) gPanicBase);
	assert((unsigned int)(location - gPanicBase) < gPanicSize);

	return (uint32_t)(uintptr_t)(location - gPanicBase);
}

void
PE_init_panicheader()
{
	if (!panic_info) {
		return;
	}

	bzero(panic_info, sizeof(struct embedded_panic_header));

	/*
	 * The panic log begins immediately after the panic header -- debugger synchronization and other functions
	 * may log into this region before we've become the exclusive panicking CPU and initialize the header here.
	 */
	panic_info->eph_panic_log_offset = debug_buf_base ? PE_get_offset_into_panic_region(debug_buf_base) : 0;

	panic_info->eph_magic = EMBEDDED_PANIC_MAGIC;
	panic_info->eph_version = EMBEDDED_PANIC_HEADER_CURRENT_VERSION;

	return;
}

/*
 * Tries to update the panic header to keep it consistent on nested panics.
 *
 * NOTE: The purpose of this function is NOT to detect/correct corruption in the panic region,
 *       it is to update the panic header to make it consistent when we nest panics.
 */
void
PE_update_panicheader_nestedpanic()
{
	/*
	 * if the panic header pointer is bogus (e.g. someone stomped on it) then bail.
	 */
	if (!panic_info) {
		/* if this happens in development then blow up bigly */
		assert(panic_info);
		return;
	}

	/*
	 * If the panic log offset is not set, re-init the panic header
	 *
	 * note that this should not be possible unless someone stomped on the panic header to zero it out, since by the time
	 * we reach this location *someone* should have appended something to the log..
	 */
	if (panic_info->eph_panic_log_offset == 0) {
		PE_init_panicheader();
		panic_info->eph_panic_flags |= EMBEDDED_PANIC_HEADER_FLAG_NESTED_PANIC;
		return;
	}

	panic_info->eph_panic_flags |= EMBEDDED_PANIC_HEADER_FLAG_NESTED_PANIC;

	/*
	 * If the panic log length is not set, set the end to
	 * the current location of the debug_buf_ptr to close it.
	 */
	if (panic_info->eph_panic_log_len == 0) {
		panic_info->eph_panic_log_len = PE_get_offset_into_panic_region(debug_buf_ptr);

		/* indicative of corruption in the panic region, consumer beware */
		if ((panic_info->eph_other_log_offset == 0) &&
		    (panic_info->eph_other_log_len == 0)) {
			panic_info->eph_panic_flags |= EMBEDDED_PANIC_HEADER_FLAG_INCOHERENT_PANICLOG;
		}
	}

	/* likely indicative of corruption in the panic region, consumer beware */
	if (((panic_info->eph_stackshot_offset == 0) && (panic_info->eph_stackshot_len == 0)) || ((panic_info->eph_stackshot_offset != 0) && (panic_info->eph_stackshot_len != 0))) {
		panic_info->eph_panic_flags |= EMBEDDED_PANIC_HEADER_FLAG_INCOHERENT_PANICLOG;
	}

	/*
	 * If we haven't set up the other log yet, set the beginning of the other log
	 * to the current location of the debug_buf_ptr
	 */
	if (panic_info->eph_other_log_offset == 0) {
		panic_info->eph_other_log_offset = PE_get_offset_into_panic_region(debug_buf_ptr);

		/* indicative of corruption in the panic region, consumer beware */
		if (panic_info->eph_other_log_len == 0) {
			panic_info->eph_panic_flags |= EMBEDDED_PANIC_HEADER_FLAG_INCOHERENT_PANICLOG;
		}
	}

	return;
}

boolean_t
PE_reboot_on_panic(void)
{
	uint32_t debug_flags;

	if (PE_i_can_has_debugger(&debug_flags)
	    && (debug_flags & DB_NMI)) {
		/* kernel debugging is active */
		return FALSE;
	} else {
		return TRUE;
	}
}

void
PE_sync_panic_buffers(void)
{
	/*
	 * rdar://problem/26453070:
	 * The iBoot panic region is write-combined on arm64.  We must flush dirty lines
	 * from L1/L2 as late as possible before reset, with no further reads of the panic
	 * region between the flush and the reset.  Some targets have an additional memcache (L3),
	 * and a read may bring dirty lines out of L3 and back into L1/L2, causing the lines to
	 * be discarded on reset.  If we can make sure the lines are flushed to L3/DRAM,
	 * the platform reset handler will flush any L3.
	 */
	if (gPanicBase) {
		#if !HAS_UCNORMAL_MEM
		CleanPoC_DcacheRegion_Force(gPanicBase, gPanicSize);
		#endif
	}
}

static void
pe_prepare_images(void)
{
	if ((1 & PE_state.video.v_rotate) != 0) {
		// Only square square images with radial symmetry are supported
		// No need to actually rotate the data

		// Swap the dx and dy offsets
		uint32_t tmp = default_progress.dx;
		default_progress.dx = default_progress.dy;
		default_progress.dy = tmp;
	}
#if 0
	uint32_t cnt, cnt2, cnt3, cnt4;
	uint32_t tmp, width, height;
	uint8_t  data, *new_data;
	const uint8_t *old_data;

	width  = default_progress.width;
	height = default_progress.height * default_progress.count;

	// Scale images if the UI is being scaled
	if (PE_state.video.v_scale > 1) {
		new_data = kalloc(width * height * scale * scale);
		if (new_data != 0) {
			old_data = default_progress_data;
			default_progress_data = new_data;
			for (cnt = 0; cnt < height; cnt++) {
				for (cnt2 = 0; cnt2 < width; cnt2++) {
					data = *(old_data++);
					for (cnt3 = 0; cnt3 < scale; cnt3++) {
						for (cnt4 = 0; cnt4 < scale; cnt4++) {
							new_data[width * scale * cnt3 + cnt4] = data;
						}
					}
					new_data += scale;
				}
				new_data += width * scale * (scale - 1);
			}
			default_progress.width  *= scale;
			default_progress.height *= scale;
			default_progress.dx     *= scale;
			default_progress.dy     *= scale;
		}
	}
#endif
}

void
PE_mark_hwaccess(uint64_t thread)
{
	last_hwaccess_thread = thread;
	__builtin_arm_dmb(DMB_ISH);
}

void
PE_mark_hwaccess_data(uint8_t type, uint8_t size, uint64_t paddr)
{
	last_hwaccess_type = type;
	last_hwaccess_size = size;
	last_hwaccess_paddr = paddr;
	__builtin_arm_dmb(DMB_ISH);
}
__startup_func
vm_size_t
PE_init_socd_client(void)
{
	DTEntry entry;
	uintptr_t const *reg_prop;
	unsigned int size;

	/*
	 * Our one and only chance to initialize is in cold boot. Post lockdown we cannot
	 * continue with initialization since the page tables are read-only.
	 */
	if (startup_phase >= STARTUP_SUB_EARLY_BOOT) {
		return 0;
	}

	if (kSuccess != SecureDTLookupEntry(0, "socd-trace-ram", &entry)) {
		return 0;
	}

	if (kSuccess != SecureDTGetProperty(entry, "reg", (void const **)&reg_prop, &size)) {
		return 0;
	}

	if (size < 2 * sizeof(uintptr_t)) {
		return 0;
	}

	socd_trace_ram_size = (vm_size_t)reg_prop[1];
	if (socd_trace_ram_size == 0) {
		return 0;
	}

	socd_trace_ram_base = ml_io_map(reg_prop[0], socd_trace_ram_size);

	return socd_trace_ram_size;
}

/*
 *  see comments in PE_write_socd_client_buffer
 */
void
PE_read_socd_client_buffer(vm_offset_t offset, void *out_buff, vm_size_t size)
{
	volatile uint32_t *client_buff = (volatile uint32_t *)(socd_trace_ram_base + offset);
	vm_size_t len = size / sizeof(client_buff[0]);

	assert(out_buff);
	assert3u((offset + size), <=, socd_trace_ram_size);

	/* Perform 4 byte aligned accesses */
	if ((offset % 4 != 0) || (size % 4 != 0)) {
		panic("unaligned read of 0x%lu bytes from socd trace ram address 0x%lu", size, offset);
	}

	for (vm_size_t i = 0; i < len; i++) {
		((uint32_t *)out_buff)[i] = client_buff[i];
	}
}

/*
 * PE_write_socd_client_buffer solves two problems:
 * 1. Prevents accidentally trusting a value read from socd client buffer. socd client buffer is considered untrusted.
 * 2. Ensures only 4 byte store instructions are used. On some platforms, socd client buffer is backed up
 *    by a SRAM that must be written to only 4 bytes at a time.
 */
void
PE_write_socd_client_buffer(vm_offset_t offset, const void *in_buff, vm_size_t size)
{
	volatile uint32_t *client_buff = (volatile uint32_t *)(socd_trace_ram_base + offset);
	vm_size_t len = size / sizeof(client_buff[0]);

	assert(in_buff);
	assert3u((offset + size), <=, socd_trace_ram_size);

	/* Perform 4 byte aligned accesses */
	if ((offset % 4 != 0) || (size % 4 != 0)) {
		panic("unaligned write of 0x%lu bytes to socd trace ram address 0x%lu", size, offset);
	}

	for (vm_size_t i = 0; i < len; i++) {
		client_buff[i] = ((const uint32_t *)in_buff)[i];
	}
}

boolean_t
PE_device_is_simulated(void)
{
	return strnstr(gTargetTypeBuffer, "sim", sizeof(gTargetTypeBuffer)) != NULL;
}