[apple/xnu.git] / osfmk / kern / debug.c

/*
 * Copyright (c) 2000-2016 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */
/* 
 * Mach Operating System
 * Copyright (c) 1991,1990,1989 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */

#include <mach_assert.h>
#include <mach_kdp.h>
#include <kdp/kdp.h>
#include <kdp/kdp_core.h>
#include <kdp/kdp_internal.h>
#include <kdp/kdp_callout.h>
#include <kern/cpu_number.h>
#include <kern/kalloc.h>
#include <kern/spl.h>
#include <kern/thread.h>
#include <kern/assert.h>
#include <kern/sched_prim.h>
#include <kern/misc_protos.h>
#include <kern/clock.h>
#include <kern/telemetry.h>
#include <kern/ecc.h>
#include <kern/kern_cdata.h>
#include <kern/zalloc.h>
#include <vm/vm_kern.h>
#include <vm/pmap.h>
#include <stdarg.h>
#include <stdatomic.h>
#include <sys/pgo.h>
#include <console/serial_protos.h>

#if !(MACH_KDP && CONFIG_KDP_INTERACTIVE_DEBUGGING)
#include <kdp/kdp_udp.h>
#endif
#include <kern/processor.h>

#if defined(__i386__) || defined(__x86_64__)
#include <i386/cpu_threads.h>
#include <i386/pmCPU.h>
#endif

#include <IOKit/IOPlatformExpert.h>
#include <machine/pal_routines.h>

#include <sys/kdebug.h>
#include <libkern/OSKextLibPrivate.h>
#include <libkern/OSAtomic.h>
#include <libkern/kernel_mach_header.h>
#include <libkern/section_keywords.h>
#include <uuid/uuid.h>
#include <mach_debug/zone_info.h>

#include <os/log_private.h>

#if CONFIG_EMBEDDED
#include <pexpert/pexpert.h> /* For gPanicBase */
#include <arm/caches_internal.h>
#include <arm/misc_protos.h>
extern volatile struct xnu_hw_shmem_dbg_command_info *hwsd_info;
#endif


unsigned int    halt_in_debugger = 0;
unsigned int    current_debugger = 0;
unsigned int    active_debugger = 0;
unsigned int    panicDebugging = FALSE;
unsigned int    kdebug_serial = FALSE;
unsigned int    kernel_debugger_entry_count = 0;


#if defined(__arm__)
#define TRAP_DEBUGGER __asm__ volatile("trap")
#elif defined(__arm64__)
/*
 * Magic number; this should be identical to the __arm__ encoding for trap.
 */
#define TRAP_DEBUGGER __asm__ volatile(".long 0xe7ffdeff")
#elif defined (__x86_64__)
#define TRAP_DEBUGGER __asm__("int3")
#else
#error No TRAP_DEBUGGER for this architecture
#endif

#if defined(__i386__) || defined(__x86_64__)
#define panic_stop()    pmCPUHalt(PM_HALT_PANIC)
#else
#define panic_stop()    panic_spin_forever()
#endif

#define CPUDEBUGGEROP PROCESSOR_DATA(current_processor(), debugger_state).db_current_op
#define CPUDEBUGGERMSG PROCESSOR_DATA(current_processor(), debugger_state).db_message
#define CPUPANICSTR PROCESSOR_DATA(current_processor(), debugger_state).db_panic_str
#define CPUPANICARGS PROCESSOR_DATA(current_processor(), debugger_state).db_panic_args
#define CPUPANICOPTS PROCESSOR_DATA(current_processor(), debugger_state).db_panic_options
#define CPUDEBUGGERSYNC PROCESSOR_DATA(current_processor(), debugger_state).db_proceed_on_sync_failure
#define CPUDEBUGGERCOUNT PROCESSOR_DATA(current_processor(), debugger_state).db_entry_count
#define CPUDEBUGGERRET PROCESSOR_DATA(current_processor(), debugger_state).db_op_return
#define CPUPANICCALLER PROCESSOR_DATA(current_processor(), debugger_state).db_panic_caller

#if DEVELOPMENT || DEBUG
#define DEBUGGER_DEBUGGING_NESTED_PANIC_IF_REQUESTED(requested)                                 \
MACRO_BEGIN                                                                                     \
        if (requested) {                                                                        \
                volatile int *badpointer = (int *)4;                                                    \
                *badpointer = 0;                                                                \
        }                                                                                       \
MACRO_END
#endif /* DEVELOPMENT || DEBUG */

debugger_op debugger_current_op = DBOP_NONE;
const char *debugger_panic_str = NULL;
va_list *debugger_panic_args = NULL;
uint64_t debugger_panic_options = 0;
const char *debugger_message = NULL;
unsigned long debugger_panic_caller = 0;

void panic_trap_to_debugger(const char *panic_format_str, va_list *panic_args, unsigned int reason, void *ctx, uint64_t panic_options_mask, unsigned long panic_caller);
static void kdp_machine_reboot_type(unsigned int type);
__attribute__((noreturn)) void panic_spin_forever(void);
extern kern_return_t do_stackshot(void);

int mach_assert = 1;

#define NESTEDDEBUGGERENTRYMAX 5

#if CONFIG_EMBEDDED
#define DEBUG_BUF_SIZE (4096)
#define KDBG_TRACE_PANIC_FILENAME "/var/log/panic.trace"
#else
/*
 * EXTENDED_/DEBUG_BUF_SIZE can't grow without updates to SMC and iBoot to store larger panic logs on co-processor systems */
#define DEBUG_BUF_SIZE ((3 * PAGE_SIZE) + offsetof(struct macos_panic_header, mph_data))
#define EXTENDED_DEBUG_BUF_SIZE 0x0013ff80
#define KDBG_TRACE_PANIC_FILENAME "/var/tmp/panic.trace"
#endif

/* debug_buf is directly linked with iBoot panic region for embedded targets */
#if CONFIG_EMBEDDED
char *debug_buf_base = NULL;
char *debug_buf_ptr = NULL;
unsigned int debug_buf_size = 0;
#else
char debug_buf[DEBUG_BUF_SIZE];
struct macos_panic_header *panic_info = (struct macos_panic_header *)debug_buf;
char *debug_buf_base = (debug_buf + offsetof(struct macos_panic_header, mph_data));
char *debug_buf_ptr = (debug_buf + offsetof(struct macos_panic_header, mph_data));

/*
 * We don't include the size of the panic header in the length of the data we actually write.
 * On co-processor platforms, we lose sizeof(struct macos_panic_header) bytes from the end of
 * the end of the log because we only support writing (3*PAGESIZE) bytes.
 */
unsigned int debug_buf_size = (DEBUG_BUF_SIZE - offsetof(struct macos_panic_header, mph_data));

boolean_t extended_debug_log_enabled = FALSE;
#endif

/* Debugger state */
atomic_int     debugger_cpu = ATOMIC_VAR_INIT(DEBUGGER_NO_CPU);
boolean_t      debugger_allcpus_halted = FALSE;
boolean_t      debugger_safe_to_return = TRUE;
unsigned int   debugger_context = 0;

static char model_name[64];
unsigned char *kernel_uuid;

/*
 * By default we treat Debugger() the same as calls to panic(), unless
 * we have debug boot-args present and the DB_KERN_DUMP_ON_NMI *NOT* set.
 * If DB_KERN_DUMP_ON_NMI is *NOT* set, return from Debugger() is supported.
 *
 * Return from Debugger() is currently only implemented on x86
 */
static boolean_t debugger_is_panic = TRUE;

#if DEVELOPMENT || DEBUG
boolean_t debug_boot_arg_inited = FALSE;
#endif

SECURITY_READ_ONLY_LATE(unsigned int) debug_boot_arg;

char kernel_uuid_string[37]; /* uuid_string_t */
char   panic_disk_error_description[512];
size_t panic_disk_error_description_size = sizeof(panic_disk_error_description);

extern unsigned int write_trace_on_panic;
int kext_assertions_enable =
#if DEBUG || DEVELOPMENT
                        TRUE;
#else
                        FALSE;
#endif

void
panic_init(void)
{
        unsigned long uuidlen = 0;
        void *uuid;

        uuid = getuuidfromheader(&_mh_execute_header, &uuidlen);
        if ((uuid != NULL) && (uuidlen == sizeof(uuid_t))) {
                kernel_uuid = uuid;
                uuid_unparse_upper(*(uuid_t *)uuid, kernel_uuid_string);
        }

        if (!PE_parse_boot_argn("assertions", &mach_assert, sizeof(mach_assert))) {
                mach_assert = 1;
        }

        /*
         * Initialize the value of the debug boot-arg
         */
        debug_boot_arg = 0;
#if ((CONFIG_EMBEDDED && MACH_KDP) || defined(__x86_64__))
        if (PE_parse_boot_argn("debug", &debug_boot_arg, sizeof (debug_boot_arg))) {
#if DEVELOPMENT || DEBUG
                if (debug_boot_arg & DB_HALT) {
                        halt_in_debugger=1;
                }
#endif

#if CONFIG_EMBEDDED
                if (debug_boot_arg & DB_NMI) {
                        panicDebugging  = TRUE;
                }
#else
                panicDebugging = TRUE;
#if KDEBUG_MOJO_TRACE
                if (debug_boot_arg & DB_PRT_KDEBUG) {
                        kdebug_serial = TRUE;
                }
#endif
#endif /* CONFIG_EMBEDDED */
        }
#endif /* ((CONFIG_EMBEDDED && MACH_KDP) || defined(__x86_64__)) */

#if DEVELOPMENT || DEBUG
        debug_boot_arg_inited = TRUE;
#endif

#if !CONFIG_EMBEDDED
        /*
         * By default we treat Debugger() the same as calls to panic(), unless
         * we have debug boot-args present and the DB_KERN_DUMP_ON_NMI *NOT* set.
         * If DB_KERN_DUMP_ON_NMI is *NOT* set, return from Debugger() is supported.
         * This is because writing an on-device corefile is a destructive operation.
         *
         * Return from Debugger() is currently only implemented on x86
         */
        if (PE_i_can_has_debugger(NULL) && !(debug_boot_arg & DB_KERN_DUMP_ON_NMI)) {
                debugger_is_panic = FALSE;
        }
#endif

}

#if defined (__x86_64__)
void
extended_debug_log_init(void)
{
        assert(coprocessor_paniclog_flush);
        /*
         * Allocate an extended panic log buffer that has space for the panic
         * stackshot at the end. Update the debug buf pointers appropriately
         * to point at this new buffer.
         */
        char *new_debug_buf = kalloc(EXTENDED_DEBUG_BUF_SIZE);
        bzero(new_debug_buf, EXTENDED_DEBUG_BUF_SIZE);

        panic_info = (struct macos_panic_header *)new_debug_buf;
        debug_buf_ptr = debug_buf_base = (new_debug_buf + offsetof(struct macos_panic_header, mph_data));
        debug_buf_size = (EXTENDED_DEBUG_BUF_SIZE - offsetof(struct macos_panic_header, mph_data));

        extended_debug_log_enabled = TRUE;
}
#endif /* defined (__x86_64__) */

void
debug_log_init(void)
{
#if CONFIG_EMBEDDED
        if (!gPanicBase) {
                printf("debug_log_init: Error!! gPanicBase is still not initialized\n");
                return;
        }
        /* Shift debug buf start location and size by the length of the panic header */
        debug_buf_base = (char *)gPanicBase + sizeof(struct embedded_panic_header);
        debug_buf_ptr = debug_buf_base;
        debug_buf_size = gPanicSize - sizeof(struct embedded_panic_header);
#else
        bzero(panic_info, DEBUG_BUF_SIZE);

        assert(debug_buf_base != NULL);
        assert(debug_buf_ptr != NULL);
        assert(debug_buf_size != 0);
#endif
}

static void
DebuggerLock()
{
        int my_cpu = cpu_number();
        int debugger_exp_cpu = DEBUGGER_NO_CPU;
        assert(ml_get_interrupts_enabled() == FALSE);

        if (debugger_cpu == my_cpu) {
                return;
        }

        while(!atomic_compare_exchange_strong(&debugger_cpu, &debugger_exp_cpu, my_cpu)) {
                debugger_exp_cpu = DEBUGGER_NO_CPU;
        }

        return;
}

static void
DebuggerUnlock()
{
        assert(debugger_cpu == cpu_number());

        /*
         * We don't do an atomic exchange here in case
         * there's another CPU spinning to acquire the debugger_lock
         * and we never get a chance to update it. We already have the
         * lock so we can simply store DEBUGGER_NO_CPU and follow with
         * a barrier.
         */
        debugger_cpu = DEBUGGER_NO_CPU;
        OSMemoryBarrier();

        return;
}

static kern_return_t
DebuggerHaltOtherCores(boolean_t proceed_on_failure)
{
#if CONFIG_EMBEDDED
        return DebuggerXCallEnter(proceed_on_failure);
#else /* CONFIG_EMBEDDED */
#pragma unused(proceed_on_failure)
        mp_kdp_enter(proceed_on_failure);
        return KERN_SUCCESS;
#endif
}

static void
DebuggerResumeOtherCores()
{
#if CONFIG_EMBEDDED
        DebuggerXCallReturn();
#else /* CONFIG_EMBEDDED */
        mp_kdp_exit();
#endif
}

static void
DebuggerSaveState(debugger_op db_op, const char *db_message, const char *db_panic_str,
                va_list *db_panic_args, uint64_t db_panic_options,
                boolean_t db_proceed_on_sync_failure, unsigned long db_panic_caller)
{
        CPUDEBUGGEROP = db_op;

        /* Preserve the original panic message */
        if (CPUDEBUGGERCOUNT == 1 || CPUPANICSTR == NULL) {
                CPUDEBUGGERMSG = db_message;
                CPUPANICSTR = db_panic_str;
                CPUPANICARGS = db_panic_args;
                CPUPANICCALLER = db_panic_caller;
        } else if (CPUDEBUGGERCOUNT > 1 && db_panic_str != NULL) {
                kprintf("Nested panic detected:");
                if (db_panic_str != NULL)
                        _doprnt(db_panic_str, db_panic_args, PE_kputc, 0);
        }

        CPUDEBUGGERSYNC = db_proceed_on_sync_failure;
        CPUDEBUGGERRET = KERN_SUCCESS;

        /* Reset these on any nested panics */
        CPUPANICOPTS = db_panic_options;

        return;
}

/*
 * Save the requested debugger state/action into the current processor's processor_data
 * and trap to the debugger.
 */
kern_return_t
DebuggerTrapWithState(debugger_op db_op, const char *db_message, const char *db_panic_str,
                va_list *db_panic_args, uint64_t db_panic_options,
                boolean_t db_proceed_on_sync_failure, unsigned long db_panic_caller)
{
        kern_return_t ret;

        assert(ml_get_interrupts_enabled() == FALSE);
        DebuggerSaveState(db_op, db_message, db_panic_str,
                db_panic_args, db_panic_options, db_proceed_on_sync_failure,
                db_panic_caller);

        TRAP_DEBUGGER;

        ret = CPUDEBUGGERRET;

        DebuggerSaveState(DBOP_NONE, NULL, NULL, NULL, 0, FALSE, 0);

        return ret;
}

void __attribute__((noinline))
Assert(
        const char      *file,
        int             line,
        const char      *expression
      )
{
        if (!mach_assert) {
                kprintf("%s:%d non-fatal Assertion: %s", file, line, expression);
                return;
        }

        panic_plain("%s:%d Assertion failed: %s", file, line, expression);
}


void
Debugger(const char *message)
{
        DebuggerWithContext(0, NULL, message, DEBUGGER_OPTION_NONE);
}

void
DebuggerWithContext(unsigned int reason, void *ctx, const char *message,
        uint64_t debugger_options_mask)
{
        spl_t previous_interrupts_state;
        boolean_t old_doprnt_hide_pointers = doprnt_hide_pointers;

        previous_interrupts_state = ml_set_interrupts_enabled(FALSE);
        disable_preemption();

        CPUDEBUGGERCOUNT++;

        if (CPUDEBUGGERCOUNT > NESTEDDEBUGGERENTRYMAX) {
                static boolean_t in_panic_kprintf = FALSE;

                /* Notify any listeners that we've started a panic */
                PEHaltRestart(kPEPanicBegin);

                if (!in_panic_kprintf) {
                        in_panic_kprintf = TRUE;
                        kprintf("Detected nested debugger entry count exceeding %d\n",
                                NESTEDDEBUGGERENTRYMAX);
                        in_panic_kprintf = FALSE;
                }

                if (!panicDebugging) {
                        kdp_machine_reboot_type(kPEPanicRestartCPU);
                }

                panic_spin_forever();
        }

#if DEVELOPMENT || DEBUG
        DEBUGGER_DEBUGGING_NESTED_PANIC_IF_REQUESTED((debugger_options_mask & DEBUGGER_OPTION_RECURPANIC_ENTRY));
#endif

        doprnt_hide_pointers = FALSE;

        if (ctx != NULL) {
                DebuggerSaveState(DBOP_DEBUGGER, message,
                        NULL, NULL, debugger_options_mask, TRUE, 0);
                handle_debugger_trap(reason, 0, 0, ctx);
                DebuggerSaveState(DBOP_NONE, NULL, NULL,
                        NULL, 0, FALSE, 0);
        } else {
                DebuggerTrapWithState(DBOP_DEBUGGER, message,
                        NULL, NULL, debugger_options_mask, TRUE, 0);
        }

        CPUDEBUGGERCOUNT--;
        doprnt_hide_pointers = old_doprnt_hide_pointers;
        enable_preemption();
        ml_set_interrupts_enabled(previous_interrupts_state);
}

static struct kdp_callout {
        struct kdp_callout * callout_next;
        kdp_callout_fn_t callout_fn;
        boolean_t callout_in_progress;
        void * callout_arg;
} * kdp_callout_list = NULL;

/*
 * Called from kernel context to register a kdp event callout.
 */
void
kdp_register_callout(kdp_callout_fn_t fn, void * arg)
{
        struct kdp_callout * kcp;
        struct kdp_callout * list_head;

        kcp = kalloc(sizeof(*kcp));
        if (kcp == NULL)
                panic("kdp_register_callout() kalloc failed");

        kcp->callout_fn = fn;
        kcp->callout_arg = arg;
        kcp->callout_in_progress = FALSE;

        /* Lock-less list insertion using compare and exchange. */
        do {
                list_head = kdp_callout_list;
                kcp->callout_next = list_head;
        } while (!OSCompareAndSwapPtr(list_head, kcp, &kdp_callout_list));
}

static void
kdp_callouts(kdp_event_t event)
{
        struct kdp_callout      *kcp = kdp_callout_list;

        while (kcp) {
                if (!kcp->callout_in_progress) {
                        kcp->callout_in_progress = TRUE;
                        kcp->callout_fn(kcp->callout_arg, event);
                        kcp->callout_in_progress = FALSE;
                }
                kcp = kcp->callout_next;
        }
}

/*
 * An overview of the xnu panic path:
 *
 * Several panic wrappers (panic(), panic_with_options(), etc.) all funnel into panic_trap_to_debugger().
 * panic_trap_to_debugger() sets the panic state in the current processor's processor_data_t prior
 * to trapping into the debugger. Once we trap to the debugger, we end up in handle_debugger_trap()
 * which tries to acquire the panic lock by atomically swapping the current CPU number into debugger_cpu.
 * debugger_cpu acts as a synchronization point, from which the winning CPU can halt the other cores and
 * continue to debugger_collect_diagnostics() where we write the paniclog, corefile (if appropriate) and proceed
 * according to the device's boot-args.
 */
#undef panic
void
panic(const char *str, ...)
{
        va_list panic_str_args;

        va_start(panic_str_args, str);
        panic_trap_to_debugger(str, &panic_str_args, 0, NULL, 0, (unsigned long)(char *)__builtin_return_address(0));
        va_end(panic_str_args);
}

void
panic_with_options(unsigned int reason, void *ctx, uint64_t debugger_options_mask, const char *str, ...)
{
        va_list panic_str_args;

        va_start(panic_str_args, str);
        panic_trap_to_debugger(str, &panic_str_args, reason, ctx, debugger_options_mask, (unsigned long)(char *)__builtin_return_address(0));
        va_end(panic_str_args);
}

void
panic_context(unsigned int reason, void *ctx, const char *str, ...)
{
        va_list panic_str_args;

        va_start(panic_str_args, str);
        panic_trap_to_debugger(str, &panic_str_args, reason, ctx, 0, (unsigned long)(char *)__builtin_return_address(0));
        va_end(panic_str_args);
}

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wmissing-noreturn"
void
panic_trap_to_debugger(const char *panic_format_str, va_list *panic_args, unsigned int reason, void
                        *ctx, uint64_t panic_options_mask, unsigned long panic_caller)
{
#pragma clang diagnostic pop

        if (ml_wants_panic_trap_to_debugger()) {
                ml_panic_trap_to_debugger(panic_format_str, panic_args, reason, ctx, panic_options_mask, panic_caller);

                /*
                 * This should not return, but we return here for the tail call
                 * as it simplifies the backtrace.
                 */
                return;
        }

        CPUDEBUGGERCOUNT++;

        if (CPUDEBUGGERCOUNT > NESTEDDEBUGGERENTRYMAX) {
                static boolean_t in_panic_kprintf = FALSE;

                /* Notify any listeners that we've started a panic */
                PEHaltRestart(kPEPanicBegin);

                if (!in_panic_kprintf) {
                        in_panic_kprintf = TRUE;
                        kprintf("Detected nested debugger entry count exceeding %d\n",
                                NESTEDDEBUGGERENTRYMAX);
                        in_panic_kprintf = FALSE;
                }

                if (!panicDebugging) {
                        kdp_machine_reboot_type(kPEPanicRestartCPU);
                }

                panic_spin_forever();
        }

#if DEVELOPMENT || DEBUG
        DEBUGGER_DEBUGGING_NESTED_PANIC_IF_REQUESTED((panic_options_mask & DEBUGGER_OPTION_RECURPANIC_ENTRY));
#endif

#if CONFIG_EMBEDDED
        if (PE_arm_debug_panic_hook)
                PE_arm_debug_panic_hook(panic_format_str);
#endif

#if defined (__x86_64__)
        plctrace_disable();
#endif

        if (write_trace_on_panic && kdebug_enable) {
                if (get_preemption_level() == 0 && !ml_at_interrupt_context()) {
                        ml_set_interrupts_enabled(TRUE);
                        KDBG(TRACE_PANIC);
                        kdbg_dump_trace_to_file(KDBG_TRACE_PANIC_FILENAME);
                }
        }

        ml_set_interrupts_enabled(FALSE);
        disable_preemption();

#if defined (__x86_64__)
        pmSafeMode(x86_lcpu(), PM_SAFE_FL_SAFE);
#endif /* defined (__x86_64__) */

        /* Never hide pointers from panic logs. */
        doprnt_hide_pointers = FALSE;

        if (ctx != NULL) {
                /*
                 * We called into panic from a trap, no need to trap again. Set the
                 * state on the current CPU and then jump to handle_debugger_trap.
                 */
                DebuggerSaveState(DBOP_PANIC, "panic",
                                panic_format_str, panic_args,
                                panic_options_mask, TRUE, panic_caller);
                handle_debugger_trap(reason, 0, 0, ctx);
        }

#if defined(__arm64__)
        /*
         *  Signal to fastsim that it should open debug ports (nop on hardware)
         */
        __asm__         volatile("HINT 0x45");
#endif /* defined(__arm64__) */

        DebuggerTrapWithState(DBOP_PANIC, "panic", panic_format_str,
                        panic_args, panic_options_mask, TRUE, panic_caller);

        /*
         * Not reached.
         */
        panic_stop();
}

__attribute__((noreturn))
void
panic_spin_forever()
{
        paniclog_append_noflush("\nPlease go to https://panic.apple.com to report this panic\n");

        for (;;) { }
}

static void
kdp_machine_reboot_type(unsigned int type)
{
        printf("Attempting system restart...");
        PEHaltRestart(type);
        halt_all_cpus(TRUE);
}

void
kdp_machine_reboot(void)
{
        kdp_machine_reboot_type(kPEPanicRestartCPU);
}

/*
 * Gather and save diagnostic information about a panic (or Debugger call).
 *
 * On embedded, Debugger and Panic are treated very similarly -- WDT uses Debugger so we can
 * theoretically return from it. On desktop, Debugger is treated as a conventional debugger -- i.e no
 * paniclog is written and no core is written unless we request a core on NMI.
 *
 * This routine handles kicking off local coredumps, paniclogs, calling into the Debugger/KDP (if it's configured),
 * and calling out to any other functions we have for collecting diagnostic info.
 */
static void
debugger_collect_diagnostics(unsigned int exception, unsigned int code, unsigned int subcode, void *state)
{
#if DEVELOPMENT || DEBUG
        DEBUGGER_DEBUGGING_NESTED_PANIC_IF_REQUESTED((debugger_panic_options & DEBUGGER_OPTION_RECURPANIC_PRELOG));
#endif

#if defined(__x86_64__)
        kprintf("Debugger called: <%s>\n", debugger_message ? debugger_message : "");
#endif
        /*
         * DB_HALT (halt_in_debugger) can be requested on startup, we shouldn't generate
         * a coredump/paniclog for this type of debugger entry. If KDP isn't configured,
         * we'll just spin in kdp_raise_exception.
         */
        if (debugger_current_op == DBOP_DEBUGGER && halt_in_debugger) {
                kdp_raise_exception(exception, code, subcode, state);
                if (debugger_safe_to_return && !debugger_is_panic) {
                        return;
                }
        }

        if ((debugger_current_op == DBOP_PANIC) ||
                ((debugger_current_op == DBOP_DEBUGGER) && debugger_is_panic)) {
                /*
                 * Attempt to notify listeners once and only once that we've started
                 * panicking. Only do this for Debugger() calls if we're treating
                 * Debugger() calls like panic().
                 */
                PEHaltRestart(kPEPanicBegin);

                /*
                 * Set the begin pointer in the panic log structure. We key off of this
                 * static variable rather than contents from the panic header itself in case someone
                 * has stomped over the panic_info structure. Also initializes the header magic.
                 */
                static boolean_t began_writing_paniclog = FALSE;
                if (!began_writing_paniclog) {
                        PE_init_panicheader();
                        began_writing_paniclog = TRUE;
                } else {
                        /*
                         * If we reached here, update the panic header to keep it as consistent
                         * as possible during a nested panic
                         */
                        PE_update_panicheader_nestedpanic();
                }
        }

        /*
         * Write panic string if this was a panic.
         *
         * TODO: Consider moving to SavePanicInfo as this is part of the panic log.
         */
        if (debugger_current_op == DBOP_PANIC) {
                paniclog_append_noflush("panic(cpu %d caller 0x%lx): ", (unsigned) cpu_number(), debugger_panic_caller);
                if (debugger_panic_str) {
                        _doprnt(debugger_panic_str, debugger_panic_args, consdebug_putc, 0);
                }
                paniclog_append_noflush("\n");
        }
#if defined(__x86_64__)
        else if (((debugger_current_op == DBOP_DEBUGGER) && debugger_is_panic)) {
                paniclog_append_noflush("Debugger called: <%s>\n", debugger_message ? debugger_message : "");
        }

        /*
         * Debugger() is treated like panic() on embedded -- for example we use it for WDT
         * panics (so we need to write a paniclog). On desktop Debugger() is used in the
         * conventional sense.
         */
        if (debugger_current_op == DBOP_PANIC || ((debugger_current_op == DBOP_DEBUGGER) && debugger_is_panic))
#endif
        {
                kdp_callouts(KDP_EVENT_PANICLOG);

                /*
                 * Write paniclog and panic stackshot (if supported)
                 * TODO: Need to clear panic log when return from debugger
                 * hooked up for embedded
                 */
                SavePanicInfo(debugger_message, debugger_panic_options);

#if DEVELOPMENT || DEBUG
                DEBUGGER_DEBUGGING_NESTED_PANIC_IF_REQUESTED((debugger_panic_options & DEBUGGER_OPTION_RECURPANIC_POSTLOG));
#endif

                /* DEBUGGER_OPTION_PANICLOGANDREBOOT is used for two finger resets on embedded so we get a paniclog */
                if (debugger_panic_options & DEBUGGER_OPTION_PANICLOGANDREBOOT)
                        PEHaltRestart(kPEPanicRestartCPU);
        }

#if CONFIG_KDP_INTERACTIVE_DEBUGGING
        PE_i_can_has_debugger(NULL);

        /*
         * If reboot on panic is enabled and the caller of panic indicated that we should skip
         * local coredumps, don't try to write these and instead go straight to reboot. This
         * allows us to persist any data that's stored in the panic log.
         */
        if ((debugger_panic_options & DEBUGGER_OPTION_SKIP_LOCAL_COREDUMP) &&
                (debug_boot_arg & DB_REBOOT_POST_CORE)) {
                kdp_machine_reboot_type(kPEPanicRestartCPU);
        }

        /*
         * Consider generating a local corefile if the infrastructure is configured
         * and we haven't disabled on-device coredumps.
         */
        if (kdp_has_polled_corefile() && !(debug_boot_arg & DB_DISABLE_LOCAL_CORE)) {
                int ret = -1;

#if defined (__x86_64__)
                /* On x86 we don't do a coredump on Debugger unless the DB_KERN_DUMP_ON_NMI boot-arg is specified. */
                if (debugger_current_op != DBOP_DEBUGGER || (debug_boot_arg & DB_KERN_DUMP_ON_NMI))
#endif
                {
                        /*
                         * Doing an on-device coredump leaves the disk driver in a state
                         * that can not be resumed.
                         */
                        debugger_safe_to_return = FALSE;
                        begin_panic_transfer();
                        ret = kern_dump(KERN_DUMP_DISK);
                        abort_panic_transfer();

#if DEVELOPMENT || DEBUG
                        DEBUGGER_DEBUGGING_NESTED_PANIC_IF_REQUESTED((debugger_panic_options & DEBUGGER_OPTION_RECURPANIC_POSTCORE));
#endif
                }

                /* If we wrote a corefile and DB_REBOOT_POST_CORE is set, reboot */
                if (ret == 0 && (debug_boot_arg & DB_REBOOT_POST_CORE)) {
                        kdp_machine_reboot_type(kPEPanicRestartCPU);
                }
        }

        /* If KDP is configured, try to trap to the debugger */
        if (current_debugger != NO_CUR_DB) {
                kdp_raise_exception(exception, code, subcode, state);
                /*
                 * Only return if we entered via Debugger and it's safe to return
                 * (we halted the other cores successfully, this isn't a nested panic, etc)
                */
                if (debugger_current_op == DBOP_DEBUGGER &&
                                debugger_safe_to_return &&
                                kernel_debugger_entry_count == 1 &&
                                !debugger_is_panic) {
                        return;
                }
        }

#if CONFIG_EMBEDDED
        if (panicDebugging) {
                /* If panic debugging is configured, spin for astris to connect */
                panic_spin_shmcon();
        }
#endif /* CONFIG_EMBEDDED */
#endif /* CONFIG_KDP_INTERACTIVE_DEBUGGING */

        if (!panicDebugging) {
                kdp_machine_reboot_type(kPEPanicRestartCPU);
        }

        panic_spin_forever();
}

#if INTERRUPT_MASKED_DEBUG
uint64_t debugger_trap_timestamps[9];
# define DEBUGGER_TRAP_TIMESTAMP(i) debugger_trap_timestamps[i] = mach_absolute_time();
#else
# define DEBUGGER_TRAP_TIMESTAMP(i)
#endif

void
handle_debugger_trap(unsigned int exception, unsigned int code, unsigned int subcode, void *state)
{
        unsigned int initial_not_in_kdp = not_in_kdp;
        kern_return_t ret;
        debugger_op db_prev_op = debugger_current_op;

        DEBUGGER_TRAP_TIMESTAMP(0);

        DebuggerLock();
        ret = DebuggerHaltOtherCores(CPUDEBUGGERSYNC);

        DEBUGGER_TRAP_TIMESTAMP(1);

#if INTERRUPT_MASKED_DEBUG
        if (serialmode & SERIALMODE_OUTPUT) {
                ml_spin_debug_reset(current_thread());
        }
#endif
        if (ret != KERN_SUCCESS) {
                CPUDEBUGGERRET = ret;
                DebuggerUnlock();
                return;
        }

        /* Update the global panic/debugger nested entry level */
        kernel_debugger_entry_count = CPUDEBUGGERCOUNT;

        /*
         * TODO: Should we do anything special for nested panics here? i.e. if we've trapped more than twice
         * should we call into the debugger if it's configured and then reboot if the panic log has been written?
         */

        if (CPUDEBUGGEROP == DBOP_NONE) {
                /* If there was no debugger context setup, we trapped due to a software breakpoint */
                debugger_current_op = DBOP_BREAKPOINT;
        } else {
                /* Not safe to return from a nested panic/debugger call */
                if (debugger_current_op == DBOP_PANIC ||
                        debugger_current_op == DBOP_DEBUGGER) {
                        debugger_safe_to_return = FALSE;
                }

                debugger_current_op = CPUDEBUGGEROP;

                /* Only overwrite the panic message if there is none already - save the data from the first call */
                if (debugger_panic_str == NULL) {
                        debugger_panic_str = CPUPANICSTR;
                        debugger_panic_args = CPUPANICARGS;
                        debugger_message = CPUDEBUGGERMSG;
                        debugger_panic_caller = CPUPANICCALLER;
                }

                debugger_panic_options = CPUPANICOPTS;
        }

        /*
         * Clear the op from the processor debugger context so we can handle
         * breakpoints in the debugger
         */
        CPUDEBUGGEROP = DBOP_NONE;

        DEBUGGER_TRAP_TIMESTAMP(2);

        kdp_callouts(KDP_EVENT_ENTER);
        not_in_kdp = 0;

        DEBUGGER_TRAP_TIMESTAMP(3);

        if (debugger_current_op == DBOP_BREAKPOINT) {
                kdp_raise_exception(exception, code, subcode, state);
        } else if (debugger_current_op == DBOP_STACKSHOT) {
                CPUDEBUGGERRET = do_stackshot();
#if PGO
        } else if (debugger_current_op == DBOP_RESET_PGO_COUNTERS) {
                CPUDEBUGGERRET = do_pgo_reset_counters();
#endif
        } else {
                debugger_collect_diagnostics(exception, code, subcode, state);
        }

        DEBUGGER_TRAP_TIMESTAMP(4);

        not_in_kdp = initial_not_in_kdp;
        kdp_callouts(KDP_EVENT_EXIT);

        DEBUGGER_TRAP_TIMESTAMP(5);

        if (debugger_current_op != DBOP_BREAKPOINT) {
                debugger_panic_str = NULL;
                debugger_panic_args = NULL;
                debugger_panic_options = 0;
                debugger_message = NULL;
        }

        /* Restore the previous debugger state */
        debugger_current_op = db_prev_op;

        DEBUGGER_TRAP_TIMESTAMP(6);

        DebuggerResumeOtherCores();

        DEBUGGER_TRAP_TIMESTAMP(7);

        DebuggerUnlock();

        DEBUGGER_TRAP_TIMESTAMP(8);

        return;
}

__attribute__((noinline,not_tail_called))
void log(__unused int level, char *fmt, ...)
{
        void *caller = __builtin_return_address(0);
        va_list listp;
        va_list listp2;


#ifdef lint
        level++;
#endif /* lint */
#ifdef  MACH_BSD
        va_start(listp, fmt);
        va_copy(listp2, listp);

        disable_preemption();
        _doprnt(fmt, &listp, cons_putc_locked, 0);
        enable_preemption();

        va_end(listp);

        os_log_with_args(OS_LOG_DEFAULT, OS_LOG_TYPE_DEFAULT, fmt, listp2, caller);
        va_end(listp2);
#endif
}

/*
 * Per <rdar://problem/24974766>, skip appending log messages to
 * the new logging infrastructure in contexts where safety is
 * uncertain. These contexts include:
 *   - When we're in the debugger
 *   - We're in a panic
 *   - Interrupts are disabled
 *   - Or Pre-emption is disabled
 * In all the above cases, it is potentially unsafe to log messages.
 */

boolean_t
oslog_is_safe(void) {
        return (kernel_debugger_entry_count == 0 &&
                not_in_kdp == 1 &&
                get_preemption_level() == 0 &&
                ml_get_interrupts_enabled() == TRUE);
}

boolean_t
debug_mode_active(void)
{
        return ((0 != kernel_debugger_entry_count != 0) || (0 == not_in_kdp));
}

void
debug_putc(char c)
{
        if ((debug_buf_size != 0) &&
                ((debug_buf_ptr - debug_buf_base) < (int)debug_buf_size)) {
                *debug_buf_ptr=c;
                debug_buf_ptr++;
        }
}

#if defined (__x86_64__)
struct pasc {
  unsigned a: 7;
  unsigned b: 7;
  unsigned c: 7;
  unsigned d: 7;
  unsigned e: 7;
  unsigned f: 7;
  unsigned g: 7;
  unsigned h: 7;
}  __attribute__((packed));

typedef struct pasc pasc_t;

/*
 * In-place packing routines -- inefficient, but they're called at most once.
 * Assumes "buflen" is a multiple of 8. Used for compressing paniclogs on x86.
 */
int
packA(char *inbuf, uint32_t length, uint32_t buflen)
{
  unsigned int i, j = 0;
  pasc_t pack;
  
  length = MIN(((length + 7) & ~7), buflen);

  for (i = 0; i < length; i+=8)
    {
      pack.a = inbuf[i];
      pack.b = inbuf[i+1];
      pack.c = inbuf[i+2];
      pack.d = inbuf[i+3];
      pack.e = inbuf[i+4];
      pack.f = inbuf[i+5];
      pack.g = inbuf[i+6];
      pack.h = inbuf[i+7];
      bcopy ((char *) &pack, inbuf + j, 7);
      j += 7;
    }
  return j;
}

void
unpackA(char *inbuf, uint32_t length)
{
        pasc_t packs;
        unsigned i = 0;
        length = (length * 8)/7;

        while (i < length) {
          packs = *(pasc_t *)&inbuf[i];
          bcopy(&inbuf[i+7], &inbuf[i+8], MAX(0, (int) (length - i - 8)));
          inbuf[i++] = packs.a;
          inbuf[i++] = packs.b;
          inbuf[i++] = packs.c;
          inbuf[i++] = packs.d;
          inbuf[i++] = packs.e;
          inbuf[i++] = packs.f;
          inbuf[i++] = packs.g;
          inbuf[i++] = packs.h;
        }
}
#endif /* defined (__x86_64__) */

extern void *proc_name_address(void *p);

static void
panic_display_process_name(void) {
        /* because of scoping issues len(p_comm) from proc_t is hard coded here */
        char proc_name[17] = "Unknown";
        task_t ctask = 0;
        void *cbsd_info = 0;

        if (ml_nofault_copy((vm_offset_t)&current_thread()->task, (vm_offset_t) &ctask, sizeof(task_t)) == sizeof(task_t))
                if(ml_nofault_copy((vm_offset_t)&ctask->bsd_info, (vm_offset_t)&cbsd_info, sizeof(cbsd_info)) == sizeof(cbsd_info))
                        if (cbsd_info && (ml_nofault_copy((vm_offset_t) proc_name_address(cbsd_info), (vm_offset_t) &proc_name, sizeof(proc_name)) > 0))
                                proc_name[sizeof(proc_name) - 1] = '\0';
        paniclog_append_noflush("\nBSD process name corresponding to current thread: %s\n", proc_name);
}

unsigned
panic_active(void) {
        return ((debugger_panic_str != (char *) 0));
}

void
populate_model_name(char *model_string) {
        strlcpy(model_name, model_string, sizeof(model_name));
}

void
panic_display_model_name(void) {
        char tmp_model_name[sizeof(model_name)];

        if (ml_nofault_copy((vm_offset_t) &model_name, (vm_offset_t) &tmp_model_name, sizeof(model_name)) != sizeof(model_name))
                return;

        tmp_model_name[sizeof(tmp_model_name) - 1] = '\0';

        if (tmp_model_name[0] != 0)
                paniclog_append_noflush("System model name: %s\n", tmp_model_name);
}

void
panic_display_kernel_uuid(void) {
        char tmp_kernel_uuid[sizeof(kernel_uuid_string)];

        if (ml_nofault_copy((vm_offset_t) &kernel_uuid_string, (vm_offset_t) &tmp_kernel_uuid, sizeof(kernel_uuid_string)) != sizeof(kernel_uuid_string))
                return;

        if (tmp_kernel_uuid[0] != '\0')
                paniclog_append_noflush("Kernel UUID: %s\n", tmp_kernel_uuid);
}

void
panic_display_kernel_aslr(void) {
        if (vm_kernel_slide) {
                paniclog_append_noflush("Kernel slide:     0x%016lx\n", (unsigned long) vm_kernel_slide);
                paniclog_append_noflush("Kernel text base: %p\n", (void *) vm_kernel_stext);
        }
}

void
panic_display_hibb(void) {
#if defined(__i386__) || defined (__x86_64__)
        paniclog_append_noflush("__HIB  text base: %p\n", (void *) vm_hib_base);
#endif
}

static void
panic_display_uptime(void) {
        uint64_t        uptime;
        absolutetime_to_nanoseconds(mach_absolute_time(), &uptime);

        paniclog_append_noflush("\nSystem uptime in nanoseconds: %llu\n", uptime);
}

static void
panic_display_disk_errors(void) {

        if (panic_disk_error_description[0]) {
                panic_disk_error_description[sizeof(panic_disk_error_description) - 1] = '\0';
                paniclog_append_noflush("Root disk errors: \"%s\"\n", panic_disk_error_description);
        }
};

extern const char version[];
extern char osversion[];

static volatile uint32_t config_displayed = 0;

__private_extern__ void
panic_display_system_configuration(boolean_t launchd_exit) {

        if (!launchd_exit) panic_display_process_name();
        if (OSCompareAndSwap(0, 1, &config_displayed)) {
                char buf[256];
                if (!launchd_exit && strlcpy(buf, PE_boot_args(), sizeof(buf)))
                        paniclog_append_noflush("Boot args: %s\n", buf);
                paniclog_append_noflush("\nMac OS version:\n%s\n",
                    (osversion[0] != 0) ? osversion : "Not yet set");
                paniclog_append_noflush("\nKernel version:\n%s\n",version);
                panic_display_kernel_uuid();
                if (!launchd_exit) {
                        panic_display_kernel_aslr();
                        panic_display_hibb();
                        panic_display_pal_info();
                }
                panic_display_model_name();
                panic_display_disk_errors();
                if (!launchd_exit) {
                        panic_display_uptime();
                        panic_display_zprint();
#if CONFIG_ZLEAKS
                        panic_display_ztrace();
#endif /* CONFIG_ZLEAKS */
                        kext_dump_panic_lists(&paniclog_append_noflush);
                }
        }
}

extern unsigned int     stack_total;
extern unsigned long long stack_allocs;

#if defined (__x86_64__)
extern unsigned int     inuse_ptepages_count;
extern long long alloc_ptepages_count;
#endif

extern boolean_t panic_include_zprint;
extern mach_memory_info_t *panic_kext_memory_info;
extern vm_size_t panic_kext_memory_size;

__private_extern__ void
panic_display_zprint()
{
        if(panic_include_zprint == TRUE) {

                unsigned int    i;
                struct zone     zone_copy;

                paniclog_append_noflush("%-20s %10s %10s\n", "Zone Name", "Cur Size", "Free Size");
                for (i = 0; i < num_zones; i++) {
                        if(ml_nofault_copy((vm_offset_t)(&zone_array[i]), (vm_offset_t)&zone_copy, sizeof(struct zone)) == sizeof(struct zone)) {
                                if(zone_copy.cur_size > (1024*1024)) {
                                        paniclog_append_noflush("%-20s %10lu %10lu\n",zone_copy.zone_name, (uintptr_t)zone_copy.cur_size,(uintptr_t)(zone_copy.countfree * zone_copy.elem_size));
                                }
                        }               
                }

                paniclog_append_noflush("%-20s %10lu\n", "Kernel Stacks", (uintptr_t)(kernel_stack_size * stack_total));

#if defined (__x86_64__)
                paniclog_append_noflush("%-20s %10lu\n", "PageTables",(uintptr_t)(PAGE_SIZE * inuse_ptepages_count));
#endif

                paniclog_append_noflush("%-20s %10lu\n", "Kalloc.Large", (uintptr_t)kalloc_large_total);
                if (panic_kext_memory_info) {
                        mach_memory_info_t *mem_info = panic_kext_memory_info;
                        paniclog_append_noflush("\n%-5s %10s\n", "Kmod", "Size");
                        for (i = 0; i < (panic_kext_memory_size / sizeof(mach_zone_info_t)); i++) {
                                if (((mem_info[i].flags & VM_KERN_SITE_TYPE) == VM_KERN_SITE_KMOD) && (mem_info[i].size > (1024 * 1024))) {
                                        paniclog_append_noflush("%-5lld %10lld\n", mem_info[i].site, mem_info[i].size);
                                }
                        }
                }
        }
}

#if CONFIG_ECC_LOGGING
__private_extern__ void
panic_display_ecc_errors() 
{
        uint32_t count = ecc_log_get_correction_count();

        if (count > 0) {
                paniclog_append_noflush("ECC Corrections:%u\n", count);
        }
}
#endif /* CONFIG_ECC_LOGGING */

#if CONFIG_ZLEAKS
extern boolean_t        panic_include_ztrace;
extern struct ztrace* top_ztrace;
void panic_print_symbol_name(vm_address_t search);

/*
 * Prints the backtrace most suspected of being a leaker, if we paniced in the zone allocator.
 * top_ztrace and panic_include_ztrace comes from osfmk/kern/zalloc.c
 */
__private_extern__ void
panic_display_ztrace(void)
{
        if(panic_include_ztrace == TRUE) {
                unsigned int i = 0;
                boolean_t keepsyms = FALSE;

                PE_parse_boot_argn("keepsyms", &keepsyms, sizeof (keepsyms));
                struct ztrace top_ztrace_copy;
                
                /* Make sure not to trip another panic if there's something wrong with memory */
                if(ml_nofault_copy((vm_offset_t)top_ztrace, (vm_offset_t)&top_ztrace_copy, sizeof(struct ztrace)) == sizeof(struct ztrace)) {
                        paniclog_append_noflush("\nBacktrace suspected of leaking: (outstanding bytes: %lu)\n", (uintptr_t)top_ztrace_copy.zt_size);
                        /* Print the backtrace addresses */
                        for (i = 0; (i < top_ztrace_copy.zt_depth && i < MAX_ZTRACE_DEPTH) ; i++) {
                                paniclog_append_noflush("%p ", top_ztrace_copy.zt_stack[i]);
                                if (keepsyms) {
                                        panic_print_symbol_name((vm_address_t)top_ztrace_copy.zt_stack[i]);
                                }
                                paniclog_append_noflush("\n");
                        }
                        /* Print any kexts in that backtrace, along with their link addresses so we can properly blame them */
                        kmod_panic_dump((vm_offset_t *)&top_ztrace_copy.zt_stack[0], top_ztrace_copy.zt_depth);
                }
                else {
                        paniclog_append_noflush("\nCan't access top_ztrace...\n");
                }
                paniclog_append_noflush("\n");
        }
}
#endif /* CONFIG_ZLEAKS */

#if !CONFIG_TELEMETRY
int
telemetry_gather(user_addr_t buffer __unused, uint32_t *length __unused, boolean_t mark __unused)
{
        return KERN_NOT_SUPPORTED;
}
#endif

#include <machine/machine_cpu.h>

uint32_t kern_feature_overrides = 0;

boolean_t kern_feature_override(uint32_t fmask) {
        if (kern_feature_overrides == 0) {
                uint32_t fdisables = 0;
                /* Expected to be first invoked early, in a single-threaded
                 * environment
                 */
                if (PE_parse_boot_argn("validation_disables", &fdisables, sizeof(fdisables))) {
                        fdisables |= KF_INITIALIZED;
                        kern_feature_overrides = fdisables;
                } else {
                        kern_feature_overrides |= KF_INITIALIZED;
                }
        }
        return ((kern_feature_overrides & fmask) == fmask);
}