// SPDX-License-Identifier: GPL-2.0
/*
 * SuperH process tracing
 *
 * Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
 * Copyright (C) 2002 - 2009  Paul Mundt
 *
 * Audit support by Yuichi Nakamura <ynakam@hitachisoft.jp>
 */
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/security.h>
#include <linux/signal.h>
#include <linux/io.h>
#include <linux/audit.h>
#include <linux/seccomp.h>
#include <linux/elf.h>
#include <linux/regset.h>
#include <linux/hw_breakpoint.h>
#include <linux/uaccess.h>
#include <asm/processor.h>
#include <asm/mmu_context.h>
#include <asm/syscalls.h>
#include <asm/fpu.h>

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

/*
 * This routine will get a word off of the process kernel stack.
 */
static inline int get_stack_long(struct task_struct *task, int offset)
{
        unsigned char *stack;

        stack = (unsigned char *)task_pt_regs(task);
        stack += offset;
        return (*((int *)stack));
}

/*
 * This routine will put a word on the process kernel stack.
 */
static inline int put_stack_long(struct task_struct *task, int offset,
                                 unsigned long data)
{
        unsigned char *stack;

        stack = (unsigned char *)task_pt_regs(task);
        stack += offset;
        *(unsigned long *) stack = data;
        return 0;
}

void ptrace_triggered(struct perf_event *bp,
                      struct perf_sample_data *data, struct pt_regs *regs)
{
        struct perf_event_attr attr;

        /*
         * Disable the breakpoint request here since ptrace has defined a
         * one-shot behaviour for breakpoint exceptions.
         */
        attr = bp->attr;
        attr.disabled = true;
        modify_user_hw_breakpoint(bp, &attr);
}

static int set_single_step(struct task_struct *tsk, unsigned long addr)
{
        struct thread_struct *thread = &tsk->thread;
        struct perf_event *bp;
        struct perf_event_attr attr;

        bp = thread->ptrace_bps[0];
        if (!bp) {
                ptrace_breakpoint_init(&attr);

                attr.bp_addr = addr;
                attr.bp_len = HW_BREAKPOINT_LEN_2;
                attr.bp_type = HW_BREAKPOINT_R;

                bp = register_user_hw_breakpoint(&attr, ptrace_triggered,
                                                 NULL, tsk);
                if (IS_ERR(bp))
                        return PTR_ERR(bp);

                thread->ptrace_bps[0] = bp;
        } else {
                int err;

                attr = bp->attr;
                attr.bp_addr = addr;
                /* reenable breakpoint */
                attr.disabled = false;
                err = modify_user_hw_breakpoint(bp, &attr);
                if (unlikely(err))
                        return err;
        }

        return 0;
}

void user_enable_single_step(struct task_struct *child)
{
        unsigned long pc = get_stack_long(child, offsetof(struct pt_regs, pc));

        set_tsk_thread_flag(child, TIF_SINGLESTEP);

        set_single_step(child, pc);
}

void user_disable_single_step(struct task_struct *child)
{
        clear_tsk_thread_flag(child, TIF_SINGLESTEP);
}

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure single step bits etc are not set.
 */
void ptrace_disable(struct task_struct *child)
{
        user_disable_single_step(child);
}

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

        return membuf_write(&to, regs, sizeof(struct pt_regs));
}

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

        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                 regs->regs,
                                 0, 16 * sizeof(unsigned long));
        if (!ret && count > 0)
                ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                         &regs->pc,
                                         offsetof(struct pt_regs, pc),
                                         sizeof(struct pt_regs));
        if (!ret)
                user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                                          sizeof(struct pt_regs), -1);

        return ret;
}

#ifdef CONFIG_SH_FPU
static int fpregs_get(struct task_struct *target,
               const struct user_regset *regset,
               struct membuf to)
{
        int ret;

        ret = init_fpu(target);
        if (ret)
                return ret;

        return membuf_write(&to, target->thread.xstate,
                            sizeof(struct user_fpu_struct));
}

static int fpregs_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;

        ret = init_fpu(target);
        if (ret)
                return ret;

        set_stopped_child_used_math(target);

        if ((boot_cpu_data.flags & CPU_HAS_FPU))
                return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                          &target->thread.xstate->hardfpu, 0, -1);

        return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                  &target->thread.xstate->softfpu, 0, -1);
}

static int fpregs_active(struct task_struct *target,
                         const struct user_regset *regset)
{
        return tsk_used_math(target) ? regset->n : 0;
}
#endif

#ifdef CONFIG_SH_DSP
static int dspregs_get(struct task_struct *target,
                       const struct user_regset *regset,
                       struct membuf to)
{
        const struct pt_dspregs *regs =
                (struct pt_dspregs *)&target->thread.dsp_status.dsp_regs;

        return membuf_write(&to, regs, sizeof(struct pt_dspregs));
}

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

        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs,
                                 0, sizeof(struct pt_dspregs));
        if (!ret)
                user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                                          sizeof(struct pt_dspregs), -1);

        return ret;
}

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

        return regs->sr & SR_DSP ? regset->n : 0;
}
#endif

const struct pt_regs_offset regoffset_table[] = {
        REGS_OFFSET_NAME(0),
        REGS_OFFSET_NAME(1),
        REGS_OFFSET_NAME(2),
        REGS_OFFSET_NAME(3),
        REGS_OFFSET_NAME(4),
        REGS_OFFSET_NAME(5),
        REGS_OFFSET_NAME(6),
        REGS_OFFSET_NAME(7),
        REGS_OFFSET_NAME(8),
        REGS_OFFSET_NAME(9),
        REGS_OFFSET_NAME(10),
        REGS_OFFSET_NAME(11),
        REGS_OFFSET_NAME(12),
        REGS_OFFSET_NAME(13),
        REGS_OFFSET_NAME(14),
        REGS_OFFSET_NAME(15),
        REG_OFFSET_NAME(pc),
        REG_OFFSET_NAME(pr),
        REG_OFFSET_NAME(sr),
        REG_OFFSET_NAME(gbr),
        REG_OFFSET_NAME(mach),
        REG_OFFSET_NAME(macl),
        REG_OFFSET_NAME(tra),
        REG_OFFSET_END,
};

/*
 * These are our native regset flavours.
 */
enum sh_regset {
        REGSET_GENERAL,
#ifdef CONFIG_SH_FPU
        REGSET_FPU,
#endif
#ifdef CONFIG_SH_DSP
        REGSET_DSP,
#endif
};

static const struct user_regset sh_regsets[] = {
        /*
         * Format is:
         *      R0 --> R15
         *      PC, PR, SR, GBR, MACH, MACL, TRA
         */
        [REGSET_GENERAL] = {
                USER_REGSET_NOTE_TYPE(PRSTATUS),
                .n              = ELF_NGREG,
                .size           = sizeof(long),
                .align          = sizeof(long),
                .regset_get             = genregs_get,
                .set            = genregs_set,
        },

#ifdef CONFIG_SH_FPU
        [REGSET_FPU] = {
                USER_REGSET_NOTE_TYPE(PRFPREG),
                .n              = sizeof(struct user_fpu_struct) / sizeof(long),
                .size           = sizeof(long),
                .align          = sizeof(long),
                .regset_get             = fpregs_get,
                .set            = fpregs_set,
                .active         = fpregs_active,
        },
#endif

#ifdef CONFIG_SH_DSP
        [REGSET_DSP] = {
                .n              = sizeof(struct pt_dspregs) / sizeof(long),
                .size           = sizeof(long),
                .align          = sizeof(long),
                .regset_get             = dspregs_get,
                .set            = dspregs_set,
                .active         = dspregs_active,
        },
#endif
};

static const struct user_regset_view user_sh_native_view = {
        .name           = "sh",
        .e_machine      = EM_SH,
        .regsets        = sh_regsets,
        .n              = ARRAY_SIZE(sh_regsets),
};

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

long arch_ptrace(struct task_struct *child, long request,
                 unsigned long addr, unsigned long data)
{
        unsigned long __user *datap = (unsigned long __user *)data;
        int ret;

        switch (request) {
        /* read the word at location addr in the USER area. */
        case PTRACE_PEEKUSR: {
                unsigned long tmp;

                ret = -EIO;
                if ((addr & 3) || addr < 0 ||
                    addr > sizeof(struct user) - 3)
                        break;

                if (addr < sizeof(struct pt_regs))
                        tmp = get_stack_long(child, addr);
                else if (addr >= offsetof(struct user, fpu) &&
                         addr < offsetof(struct user, u_fpvalid)) {
                        if (!tsk_used_math(child)) {
                                if (addr == offsetof(struct user, fpu.fpscr))
                                        tmp = FPSCR_INIT;
                                else
                                        tmp = 0;
                        } else {
                                unsigned long index;
                                ret = init_fpu(child);
                                if (ret)
                                        break;
                                index = addr - offsetof(struct user, fpu);
                                tmp = ((unsigned long *)child->thread.xstate)
                                        [index >> 2];
                        }
                } else if (addr == offsetof(struct user, u_fpvalid))
                        tmp = !!tsk_used_math(child);
                else if (addr == PT_TEXT_ADDR)
                        tmp = child->mm->start_code;
                else if (addr == PT_DATA_ADDR)
                        tmp = child->mm->start_data;
                else if (addr == PT_TEXT_END_ADDR)
                        tmp = child->mm->end_code;
                else if (addr == PT_TEXT_LEN)
                        tmp = child->mm->end_code - child->mm->start_code;
                else
                        tmp = 0;
                ret = put_user(tmp, datap);
                break;
        }

        case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
                ret = -EIO;
                if ((addr & 3) || addr < 0 ||
                    addr > sizeof(struct user) - 3)
                        break;

                if (addr < sizeof(struct pt_regs))
                        ret = put_stack_long(child, addr, data);
                else if (addr >= offsetof(struct user, fpu) &&
                         addr < offsetof(struct user, u_fpvalid)) {
                        unsigned long index;
                        ret = init_fpu(child);
                        if (ret)
                                break;
                        index = addr - offsetof(struct user, fpu);
                        set_stopped_child_used_math(child);
                        ((unsigned long *)child->thread.xstate)
                                [index >> 2] = data;
                        ret = 0;
                } else if (addr == offsetof(struct user, u_fpvalid)) {
                        conditional_stopped_child_used_math(data, child);
                        ret = 0;
                }
                break;

        case PTRACE_GETREGS:
                return copy_regset_to_user(child, &user_sh_native_view,
                                           REGSET_GENERAL,
                                           0, sizeof(struct pt_regs),
                                           datap);
        case PTRACE_SETREGS:
                return copy_regset_from_user(child, &user_sh_native_view,
                                             REGSET_GENERAL,
                                             0, sizeof(struct pt_regs),
                                             datap);
#ifdef CONFIG_SH_FPU
        case PTRACE_GETFPREGS:
                return copy_regset_to_user(child, &user_sh_native_view,
                                           REGSET_FPU,
                                           0, sizeof(struct user_fpu_struct),
                                           datap);
        case PTRACE_SETFPREGS:
                return copy_regset_from_user(child, &user_sh_native_view,
                                             REGSET_FPU,
                                             0, sizeof(struct user_fpu_struct),
                                             datap);
#endif
#ifdef CONFIG_SH_DSP
        case PTRACE_GETDSPREGS:
                return copy_regset_to_user(child, &user_sh_native_view,
                                           REGSET_DSP,
                                           0, sizeof(struct pt_dspregs),
                                           datap);
        case PTRACE_SETDSPREGS:
                return copy_regset_from_user(child, &user_sh_native_view,
                                             REGSET_DSP,
                                             0, sizeof(struct pt_dspregs),
                                             datap);
#endif
        default:
                ret = ptrace_request(child, request, addr, data);
                break;
        }

        return ret;
}

asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
{
        if (test_thread_flag(TIF_SYSCALL_TRACE) &&
            ptrace_report_syscall_entry(regs)) {
                regs->regs[0] = -ENOSYS;
                return -1;
        }

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

        if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
                trace_sys_enter(regs, regs->regs[0]);

        audit_syscall_entry(regs->regs[3], regs->regs[4], regs->regs[5],
                            regs->regs[6], regs->regs[7]);

        return 0;
}

asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
{
        int step;

        audit_syscall_exit(regs);

        if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
                trace_sys_exit(regs, regs->regs[0]);

        step = test_thread_flag(TIF_SINGLESTEP);
        if (step || test_thread_flag(TIF_SYSCALL_TRACE))
                ptrace_report_syscall_exit(regs, step);
}