// SPDX-License-Identifier: GPL-2.0-only
/*
 * arch/hexagon/kernel/kgdb.c - Hexagon KGDB Support
 *
 * Copyright (c) 2011-2012, The Linux Foundation. All rights reserved.
 */

#include <linux/irq.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/kdebug.h>
#include <linux/kgdb.h>

/* All registers are 4 bytes, for now */
#define GDB_SIZEOF_REG 4

/* The register names are used during printing of the regs;
 * Keep these at three letters to pretty-print. */
struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
        { " r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, r00)},
        { " r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, r01)},
        { " r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, r02)},
        { " r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, r03)},
        { " r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, r04)},
        { " r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, r05)},
        { " r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, r06)},
        { " r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, r07)},
        { " r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, r08)},
        { " r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, r09)},
        { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, r10)},
        { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, r11)},
        { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, r12)},
        { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, r13)},
        { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, r14)},
        { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, r15)},
        { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, r16)},
        { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, r17)},
        { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, r18)},
        { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, r19)},
        { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, r20)},
        { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, r21)},
        { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, r22)},
        { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, r23)},
        { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, r24)},
        { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, r25)},
        { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, r26)},
        { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, r27)},
        { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, r28)},
        { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, r29)},
        { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, r30)},
        { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, r31)},

        { "usr", GDB_SIZEOF_REG, offsetof(struct pt_regs, usr)},
        { "preds", GDB_SIZEOF_REG, offsetof(struct pt_regs, preds)},
        { " m0", GDB_SIZEOF_REG, offsetof(struct pt_regs, m0)},
        { " m1", GDB_SIZEOF_REG, offsetof(struct pt_regs, m1)},
        { "sa0", GDB_SIZEOF_REG, offsetof(struct pt_regs, sa0)},
        { "sa1", GDB_SIZEOF_REG, offsetof(struct pt_regs, sa1)},
        { "lc0", GDB_SIZEOF_REG, offsetof(struct pt_regs, lc0)},
        { "lc1", GDB_SIZEOF_REG, offsetof(struct pt_regs, lc1)},
        { " gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, gp)},
        { "ugp", GDB_SIZEOF_REG, offsetof(struct pt_regs, ugp)},
        { "cs0", GDB_SIZEOF_REG, offsetof(struct pt_regs, cs0)},
        { "cs1", GDB_SIZEOF_REG, offsetof(struct pt_regs, cs1)},
        { "psp", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmpsp)},
        { "elr", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmel)},
        { "est", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmest)},
        { "badva", GDB_SIZEOF_REG, offsetof(struct pt_regs, hvmer.vmbadva)},
        { "restart_r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, restart_r0)},
        { "syscall_nr", GDB_SIZEOF_REG, offsetof(struct pt_regs, syscall_nr)},
};

const struct kgdb_arch arch_kgdb_ops = {
        /* trap0(#0xDB) 0x0cdb0054 */
        .gdb_bpt_instr = {0x54, 0x00, 0xdb, 0x0c},
};

char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
{
        if (regno >= DBG_MAX_REG_NUM || regno < 0)
                return NULL;

        *((unsigned long *) mem) = *((unsigned long *) ((void *)regs +
                dbg_reg_def[regno].offset));

        return dbg_reg_def[regno].name;
}

int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
{
        if (regno >= DBG_MAX_REG_NUM || regno < 0)
                return -EINVAL;

        *((unsigned long *) ((void *)regs + dbg_reg_def[regno].offset)) =
                *((unsigned long *) mem);

        return 0;
}

void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
{
        instruction_pointer(regs) = pc;
}


/*  Not yet working  */
void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,
                                 struct task_struct *task)
{
        struct pt_regs *thread_regs;

        if (task == NULL)
                return;

        /* Initialize to zero */
        memset(gdb_regs, 0, NUMREGBYTES);

        /* Otherwise, we have only some registers from switch_to() */
        thread_regs = task_pt_regs(task);
        gdb_regs[0] = thread_regs->r00;
}

/**
 * kgdb_arch_handle_exception - Handle architecture specific GDB packets.
 * @vector: The error vector of the exception that happened.
 * @signo: The signal number of the exception that happened.
 * @err_code: The error code of the exception that happened.
 * @remcom_in_buffer: The buffer of the packet we have read.
 * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
 * @regs: The &struct pt_regs of the current process.
 *
 * This function MUST handle the 'c' and 's' command packets,
 * as well packets to set / remove a hardware breakpoint, if used.
 * If there are additional packets which the hardware needs to handle,
 * they are handled here.  The code should return -1 if it wants to
 * process more packets, and a %0 or %1 if it wants to exit from the
 * kgdb callback.
 *
 * Not yet working.
 */
int kgdb_arch_handle_exception(int vector, int signo, int err_code,
                               char *remcom_in_buffer, char *remcom_out_buffer,
                               struct pt_regs *linux_regs)
{
        switch (remcom_in_buffer[0]) {
        case 's':
        case 'c':
                return 0;
        }
        /* Stay in the debugger. */
        return -1;
}

static int __kgdb_notify(struct die_args *args, unsigned long cmd)
{
        /* cpu roundup */
        if (atomic_read(&kgdb_active) != -1) {
                kgdb_nmicallback(smp_processor_id(), args->regs);
                return NOTIFY_STOP;
        }

        if (user_mode(args->regs))
                return NOTIFY_DONE;

        if (kgdb_handle_exception(args->trapnr & 0xff, args->signr, args->err,
                                    args->regs))
                return NOTIFY_DONE;

        return NOTIFY_STOP;
}

static int
kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
{
        unsigned long flags;
        int ret;

        local_irq_save(flags);
        ret = __kgdb_notify(ptr, cmd);
        local_irq_restore(flags);

        return ret;
}

static struct notifier_block kgdb_notifier = {
        .notifier_call = kgdb_notify,

        /*
         * Lowest-prio notifier priority, we want to be notified last:
         */
        .priority = -INT_MAX,
};

/**
 * kgdb_arch_init - Perform any architecture specific initialization.
 *
 * This function will handle the initialization of any architecture
 * specific callbacks.
 */
int kgdb_arch_init(void)
{
        return register_die_notifier(&kgdb_notifier);
}

/**
 * kgdb_arch_exit - Perform any architecture specific uninitalization.
 *
 * This function will handle the uninitalization of any architecture
 * specific callbacks, for dynamic registration and unregistration.
 */
void kgdb_arch_exit(void)
{
        unregister_die_notifier(&kgdb_notifier);
}