// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.

#include <linux/audit.h>
#include <linux/elf.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/ptrace.h>
#include <linux/regset.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/signal.h>
#include <linux/smp.h>
#include <linux/uaccess.h>
#include <linux/user.h>

#include <asm/thread_info.h>
#include <asm/page.h>
#include <asm/processor.h>
#include <asm/asm-offsets.h>

#include <abi/regdef.h>
#include <abi/ckmmu.h>

#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>

/* sets the trace bits. */
#define TRACE_MODE_SI      (1 << 14)
#define TRACE_MODE_RUN     0
#define TRACE_MODE_MASK    ~(0x3 << 14)

/*
 * Make sure the single step bit is not set.
 */
static void singlestep_disable(struct task_struct *tsk)
{
        struct pt_regs *regs;

        regs = task_pt_regs(tsk);
        regs->sr = (regs->sr & TRACE_MODE_MASK) | TRACE_MODE_RUN;

        /* Enable irq */
        regs->sr |= BIT(6);
}

static void singlestep_enable(struct task_struct *tsk)
{
        struct pt_regs *regs;

        regs = task_pt_regs(tsk);
        regs->sr = (regs->sr & TRACE_MODE_MASK) | TRACE_MODE_SI;

        /* Disable irq */
        regs->sr &= ~BIT(6);
}

/*
 * Make sure the single step bit is set.
 */
void user_enable_single_step(struct task_struct *child)
{
        singlestep_enable(child);
}

void user_disable_single_step(struct task_struct *child)
{
        singlestep_disable(child);
}

enum csky_regset {
        REGSET_GPR,
        REGSET_FPR,
};

static int gpr_get(struct task_struct *target,
                   const struct user_regset *regset,
                   struct membuf to)
{
        struct pt_regs *regs = task_pt_regs(target);

        /* Abiv1 regs->tls is fake and we need sync here. */
        regs->tls = task_thread_info(target)->tp_value;

        return membuf_write(&to, regs, sizeof(*regs));
}

static int gpr_set(struct task_struct *target,
                    const struct user_regset *regset,
                    unsigned int pos, unsigned int count,
                    const void *kbuf, const void __user *ubuf)
{
        int ret;
        struct pt_regs regs;

        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &regs, 0, -1);
        if (ret)
                return ret;

        /* BIT(0) of regs.sr is Condition Code/Carry bit */
        regs.sr = (regs.sr & BIT(0)) | (task_pt_regs(target)->sr & ~BIT(0));
#ifdef CONFIG_CPU_HAS_HILO
        regs.dcsr = task_pt_regs(target)->dcsr;
#endif
        task_thread_info(target)->tp_value = regs.tls;

        *task_pt_regs(target) = regs;

        return 0;
}

static int fpr_get(struct task_struct *target,
                   const struct user_regset *regset,
                   struct membuf to)
{
        struct user_fp *regs = (struct user_fp *)&target->thread.user_fp;

#if defined(CONFIG_CPU_HAS_FPUV2) && !defined(CONFIG_CPU_HAS_VDSP)
        int i;
        struct user_fp tmp = *regs;

        for (i = 0; i < 16; i++) {
                tmp.vr[i*4] = regs->vr[i*2];
                tmp.vr[i*4 + 1] = regs->vr[i*2 + 1];
        }

        for (i = 0; i < 32; i++)
                tmp.vr[64 + i] = regs->vr[32 + i];

        return membuf_write(&to, &tmp, sizeof(tmp));
#else
        return membuf_write(&to, regs, sizeof(*regs));
#endif
}

static int fpr_set(struct task_struct *target,
                   const struct user_regset *regset,
                   unsigned int pos, unsigned int count,
                   const void *kbuf, const void __user *ubuf)
{
        int ret;
        struct user_fp *regs = (struct user_fp *)&target->thread.user_fp;

#if defined(CONFIG_CPU_HAS_FPUV2) && !defined(CONFIG_CPU_HAS_VDSP)
        int i;
        struct user_fp tmp;

        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tmp, 0, -1);

        *regs = tmp;

        for (i = 0; i < 16; i++) {
                regs->vr[i*2] = tmp.vr[i*4];
                regs->vr[i*2 + 1] = tmp.vr[i*4 + 1];
        }

        for (i = 0; i < 32; i++)
                regs->vr[32 + i] = tmp.vr[64 + i];
#else
        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
#endif

        return ret;
}

static const struct user_regset csky_regsets[] = {
        [REGSET_GPR] = {
                USER_REGSET_NOTE_TYPE(PRSTATUS),
                .n = sizeof(struct pt_regs) / sizeof(u32),
                .size = sizeof(u32),
                .align = sizeof(u32),
                .regset_get = gpr_get,
                .set = gpr_set,
        },
        [REGSET_FPR] = {
                USER_REGSET_NOTE_TYPE(PRFPREG),
                .n = sizeof(struct user_fp) / sizeof(u32),
                .size = sizeof(u32),
                .align = sizeof(u32),
                .regset_get = fpr_get,
                .set = fpr_set,
        },
};

static const struct user_regset_view user_csky_view = {
        .name = "csky",
        .e_machine = ELF_ARCH,
        .regsets = csky_regsets,
        .n = ARRAY_SIZE(csky_regsets),
};

const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
        return &user_csky_view;
}

struct pt_regs_offset {
        const char *name;
        int offset;
};

#define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
#define REG_OFFSET_END {.name = NULL, .offset = 0}

static const struct pt_regs_offset regoffset_table[] = {
        REG_OFFSET_NAME(tls),
        REG_OFFSET_NAME(lr),
        REG_OFFSET_NAME(pc),
        REG_OFFSET_NAME(sr),
        REG_OFFSET_NAME(usp),
        REG_OFFSET_NAME(orig_a0),
        REG_OFFSET_NAME(a0),
        REG_OFFSET_NAME(a1),
        REG_OFFSET_NAME(a2),
        REG_OFFSET_NAME(a3),
        REG_OFFSET_NAME(regs[0]),
        REG_OFFSET_NAME(regs[1]),
        REG_OFFSET_NAME(regs[2]),
        REG_OFFSET_NAME(regs[3]),
        REG_OFFSET_NAME(regs[4]),
        REG_OFFSET_NAME(regs[5]),
        REG_OFFSET_NAME(regs[6]),
        REG_OFFSET_NAME(regs[7]),
        REG_OFFSET_NAME(regs[8]),
        REG_OFFSET_NAME(regs[9]),
#if defined(__CSKYABIV2__)
        REG_OFFSET_NAME(exregs[0]),
        REG_OFFSET_NAME(exregs[1]),
        REG_OFFSET_NAME(exregs[2]),
        REG_OFFSET_NAME(exregs[3]),
        REG_OFFSET_NAME(exregs[4]),
        REG_OFFSET_NAME(exregs[5]),
        REG_OFFSET_NAME(exregs[6]),
        REG_OFFSET_NAME(exregs[7]),
        REG_OFFSET_NAME(exregs[8]),
        REG_OFFSET_NAME(exregs[9]),
        REG_OFFSET_NAME(exregs[10]),
        REG_OFFSET_NAME(exregs[11]),
        REG_OFFSET_NAME(exregs[12]),
        REG_OFFSET_NAME(exregs[13]),
        REG_OFFSET_NAME(exregs[14]),
        REG_OFFSET_NAME(rhi),
        REG_OFFSET_NAME(rlo),
        REG_OFFSET_NAME(dcsr),
#endif
        REG_OFFSET_END,
};

/**
 * regs_query_register_offset() - query register offset from its name
 * @name:       the name of a register
 *
 * regs_query_register_offset() returns the offset of a register in struct
 * pt_regs from its name. If the name is invalid, this returns -EINVAL;
 */
int regs_query_register_offset(const char *name)
{
        const struct pt_regs_offset *roff;

        for (roff = regoffset_table; roff->name != NULL; roff++)
                if (!strcmp(roff->name, name))
                        return roff->offset;
        return -EINVAL;
}

/**
 * regs_within_kernel_stack() - check the address in the stack
 * @regs:      pt_regs which contains kernel stack pointer.
 * @addr:      address which is checked.
 *
 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 * If @addr is within the kernel stack, it returns true. If not, returns false.
 */
static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
{
        return (addr & ~(THREAD_SIZE - 1))  ==
                (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1));
}

/**
 * regs_get_kernel_stack_nth() - get Nth entry of the stack
 * @regs:       pt_regs which contains kernel stack pointer.
 * @n:          stack entry number.
 *
 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 * this returns 0.
 */
unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
{
        unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);

        addr += n;
        if (regs_within_kernel_stack(regs, (unsigned long)addr))
                return *addr;
        else
                return 0;
}

void ptrace_disable(struct task_struct *child)
{
        singlestep_disable(child);
}

long arch_ptrace(struct task_struct *child, long request,
                 unsigned long addr, unsigned long data)
{
        long ret = -EIO;

        switch (request) {
        default:
                ret = ptrace_request(child, request, addr, data);
                break;
        }

        return ret;
}

asmlinkage int syscall_trace_enter(struct pt_regs *regs)
{
        if (test_thread_flag(TIF_SYSCALL_TRACE))
                if (ptrace_report_syscall_entry(regs))
                        return -1;

        if (secure_computing() == -1)
                return -1;

        if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
                trace_sys_enter(regs, syscall_get_nr(current, regs));

        audit_syscall_entry(regs_syscallid(regs), regs->a0, regs->a1, regs->a2, regs->a3);
        return 0;
}

asmlinkage void syscall_trace_exit(struct pt_regs *regs)
{
        audit_syscall_exit(regs);

        if (test_thread_flag(TIF_SYSCALL_TRACE))
                ptrace_report_syscall_exit(regs, 0);

        if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
                trace_sys_exit(regs, syscall_get_return_value(current, regs));
}

#ifdef CONFIG_CPU_CK860
static void show_iutlb(void)
{
        int entry, i;
        unsigned long flags;
        unsigned long oldpid;
        unsigned long entryhi[16], entrylo0[16], entrylo1[16];

        oldpid = read_mmu_entryhi();

        entry = 0x8000;

        local_irq_save(flags);

        for (i = 0; i < 16; i++) {
                write_mmu_index(entry);
                tlb_read();
                entryhi[i]  = read_mmu_entryhi();
                entrylo0[i] = read_mmu_entrylo0();
                entrylo1[i] = read_mmu_entrylo1();

                entry++;
        }

        local_irq_restore(flags);

        write_mmu_entryhi(oldpid);

        printk("\n\n\n");
        for (i = 0; i < 16; i++)
                printk("iutlb[%d]:      entryhi - 0x%lx;        entrylo0 - 0x%lx;"
                       "        entrylo1 - 0x%lx\n",
                         i, entryhi[i], entrylo0[i], entrylo1[i]);
        printk("\n\n\n");
}

static void show_dutlb(void)
{
        int entry, i;
        unsigned long flags;
        unsigned long oldpid;
        unsigned long entryhi[16], entrylo0[16], entrylo1[16];

        oldpid = read_mmu_entryhi();

        entry = 0x4000;

        local_irq_save(flags);

        for (i = 0; i < 16; i++) {
                write_mmu_index(entry);
                tlb_read();
                entryhi[i]  = read_mmu_entryhi();
                entrylo0[i] = read_mmu_entrylo0();
                entrylo1[i] = read_mmu_entrylo1();

                entry++;
        }

        local_irq_restore(flags);

        write_mmu_entryhi(oldpid);

        printk("\n\n\n");
        for (i = 0; i < 16; i++)
                printk("dutlb[%d]:      entryhi - 0x%lx;        entrylo0 - 0x%lx;"
                       "        entrylo1 - 0x%lx\n",
                         i, entryhi[i], entrylo0[i], entrylo1[i]);
        printk("\n\n\n");
}

static unsigned long entryhi[1024], entrylo0[1024], entrylo1[1024];
static void show_jtlb(void)
{
        int entry;
        unsigned long flags;
        unsigned long oldpid;

        oldpid = read_mmu_entryhi();

        entry = 0;

        local_irq_save(flags);
        while (entry < 1024) {
                write_mmu_index(entry);
                tlb_read();
                entryhi[entry]  = read_mmu_entryhi();
                entrylo0[entry] = read_mmu_entrylo0();
                entrylo1[entry] = read_mmu_entrylo1();

                entry++;
        }
        local_irq_restore(flags);

        write_mmu_entryhi(oldpid);

        printk("\n\n\n");

        for (entry = 0; entry < 1024; entry++)
                printk("jtlb[%x]:       entryhi - 0x%lx;        entrylo0 - 0x%lx;"
                       "        entrylo1 - 0x%lx\n",
                         entry, entryhi[entry], entrylo0[entry], entrylo1[entry]);
        printk("\n\n\n");
}

static void show_tlb(void)
{
        show_iutlb();
        show_dutlb();
        show_jtlb();
}
#else
static void show_tlb(void)
{
        return;
}
#endif

void show_regs(struct pt_regs *fp)
{
        pr_info("\nCURRENT PROCESS:\n\n");
        pr_info("COMM=%s PID=%d\n", current->comm, current->pid);

        if (current->mm) {
                pr_info("TEXT=%08x-%08x DATA=%08x-%08x BSS=%08x-%08x\n",
                       (int) current->mm->start_code,
                       (int) current->mm->end_code,
                       (int) current->mm->start_data,
                       (int) current->mm->end_data,
                       (int) current->mm->end_data,
                       (int) current->mm->brk);
                pr_info("USER-STACK=%08x  KERNEL-STACK=%08x\n\n",
                       (int) current->mm->start_stack,
                       (int) (((unsigned long) current) + 2 * PAGE_SIZE));
        }

        pr_info("PC: 0x%08lx (%pS)\n", (long)fp->pc, (void *)fp->pc);
        pr_info("LR: 0x%08lx (%pS)\n", (long)fp->lr, (void *)fp->lr);
        pr_info("SP: 0x%08lx\n", (long)fp->usp);
        pr_info("PSR: 0x%08lx\n", (long)fp->sr);
        pr_info("orig_a0: 0x%08lx\n", fp->orig_a0);
        pr_info("PT_REGS: 0x%08lx\n", (long)fp);

        pr_info(" a0: 0x%08lx   a1: 0x%08lx   a2: 0x%08lx   a3: 0x%08lx\n",
                fp->a0, fp->a1, fp->a2, fp->a3);
#if defined(__CSKYABIV2__)
        pr_info(" r4: 0x%08lx   r5: 0x%08lx   r6: 0x%08lx   r7: 0x%08lx\n",
                fp->regs[0], fp->regs[1], fp->regs[2], fp->regs[3]);
        pr_info(" r8: 0x%08lx   r9: 0x%08lx  r10: 0x%08lx  r11: 0x%08lx\n",
                fp->regs[4], fp->regs[5], fp->regs[6], fp->regs[7]);
        pr_info("r12: 0x%08lx  r13: 0x%08lx  r15: 0x%08lx\n",
                fp->regs[8], fp->regs[9], fp->lr);
        pr_info("r16: 0x%08lx  r17: 0x%08lx  r18: 0x%08lx  r19: 0x%08lx\n",
                fp->exregs[0], fp->exregs[1], fp->exregs[2], fp->exregs[3]);
        pr_info("r20: 0x%08lx  r21: 0x%08lx  r22: 0x%08lx  r23: 0x%08lx\n",
                fp->exregs[4], fp->exregs[5], fp->exregs[6], fp->exregs[7]);
        pr_info("r24: 0x%08lx  r25: 0x%08lx  r26: 0x%08lx  r27: 0x%08lx\n",
                fp->exregs[8], fp->exregs[9], fp->exregs[10], fp->exregs[11]);
        pr_info("r28: 0x%08lx  r29: 0x%08lx  r30: 0x%08lx  tls: 0x%08lx\n",
                fp->exregs[12], fp->exregs[13], fp->exregs[14], fp->tls);
        pr_info(" hi: 0x%08lx   lo: 0x%08lx\n",
                fp->rhi, fp->rlo);
#else
        pr_info(" r6: 0x%08lx   r7: 0x%08lx   r8: 0x%08lx   r9: 0x%08lx\n",
                fp->regs[0], fp->regs[1], fp->regs[2], fp->regs[3]);
        pr_info("r10: 0x%08lx  r11: 0x%08lx  r12: 0x%08lx  r13: 0x%08lx\n",
                fp->regs[4], fp->regs[5], fp->regs[6], fp->regs[7]);
        pr_info("r14: 0x%08lx   r1: 0x%08lx\n",
                fp->regs[8], fp->regs[9]);
#endif

        show_tlb();

        return;
}