/*
 * arch/sh/kernel/ptrace_64.c
 *
 * Copyright (C) 2000, 2001  Paolo Alberelli
 * Copyright (C) 2003 - 2008  Paul Mundt
 *
 * Started from SH3/4 version:
 *   SuperH version:   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
 *
 *   Original x86 implementation:
 *      By Ross Biro 1/23/92
 *      edited by Linus Torvalds
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/kernel.h>
#include <linux/rwsem.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/signal.h>
#include <linux/syscalls.h>
#include <linux/audit.h>
#include <linux/seccomp.h>
#include <linux/tracehook.h>
#include <linux/elf.h>
#include <linux/regset.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.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 mask defines the bits of the SR which the user is not allowed to
   change, which are everything except S, Q, M, PR, SZ, FR. */
#define SR_MASK      (0xffff8cfd)

/*
 * does not yet catch signals sent when the child dies.
 * in exit.c or in signal.c.
 */

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

        stack = (unsigned char *)(task->thread.uregs);
        stack += offset;
        return (*((int *)stack));
}

static inline unsigned long
get_fpu_long(struct task_struct *task, unsigned long addr)
{
        unsigned long tmp;
        struct pt_regs *regs;
        regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;

        if (!tsk_used_math(task)) {
                if (addr == offsetof(struct user_fpu_struct, fpscr)) {
                        tmp = FPSCR_INIT;
                } else {
                        tmp = 0xffffffffUL; /* matches initial value in fpu.c */
                }
                return tmp;
        }

        if (last_task_used_math == task) {
                enable_fpu();
                save_fpu(task, regs);
                disable_fpu();
                last_task_used_math = 0;
                regs->sr |= SR_FD;
        }

        tmp = ((long *)&task->thread.fpu)[addr / sizeof(unsigned long)];
        return tmp;
}

/*
 * This routine will put a word into the user area in 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->thread.uregs);
        stack += offset;
        *(unsigned long *) stack = data;
        return 0;
}

static inline int
put_fpu_long(struct task_struct *task, unsigned long addr, unsigned long data)
{
        struct pt_regs *regs;

        regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;

        if (!tsk_used_math(task)) {
                fpinit(&task->thread.fpu.hard);
                set_stopped_child_used_math(task);
        } else if (last_task_used_math == task) {
                enable_fpu();
                save_fpu(task, regs);
                disable_fpu();
                last_task_used_math = 0;
                regs->sr |= SR_FD;
        }

        ((long *)&task->thread.fpu)[addr / sizeof(unsigned long)] = data;
        return 0;
}

void user_enable_single_step(struct task_struct *child)
{
        struct pt_regs *regs = child->thread.uregs;

        regs->sr |= SR_SSTEP;   /* auto-resetting upon exception */
}

void user_disable_single_step(struct task_struct *child)
{
        struct pt_regs *regs = child->thread.uregs;

        regs->sr &= ~SR_SSTEP;
}

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

        /* PC, SR, SYSCALL */
        ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
                                  &regs->pc,
                                  0, 3 * sizeof(unsigned long long));

        /* R1 -> R63 */
        if (!ret)
                ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
                                          regs->regs,
                                          offsetof(struct pt_regs, regs[0]),
                                          63 * sizeof(unsigned long long));
        /* TR0 -> TR7 */
        if (!ret)
                ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
                                          regs->tregs,
                                          offsetof(struct pt_regs, tregs[0]),
                                          8 * sizeof(unsigned long long));

        if (!ret)
                ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
                                               sizeof(struct pt_regs), -1);

        return ret;
}

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;

        /* PC, SR, SYSCALL */
        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                 &regs->pc,
                                 0, 3 * sizeof(unsigned long long));

        /* R1 -> R63 */
        if (!ret && count > 0)
                ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                         regs->regs,
                                         offsetof(struct pt_regs, regs[0]),
                                         63 * sizeof(unsigned long long));

        /* TR0 -> TR7 */
        if (!ret && count > 0)
                ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                         regs->tregs,
                                         offsetof(struct pt_regs, tregs[0]),
                                         8 * sizeof(unsigned long long));

        if (!ret)
                ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                                                sizeof(struct pt_regs), -1);

        return ret;
}

#ifdef CONFIG_SH_FPU
int fpregs_get(struct task_struct *target,
               const struct user_regset *regset,
               unsigned int pos, unsigned int count,
               void *kbuf, void __user *ubuf)
{
        int ret;

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

        return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
                                   &target->thread.fpu.hard, 0, -1);
}

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);

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

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

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

static const struct user_regset sh_regsets[] = {
        /*
         * Format is:
         *      PC, SR, SYSCALL,
         *      R1 --> R63,
         *      TR0 --> TR7,
         */
        [REGSET_GENERAL] = {
                .core_note_type = NT_PRSTATUS,
                .n              = ELF_NGREG,
                .size           = sizeof(long long),
                .align          = sizeof(long long),
                .get            = genregs_get,
                .set            = genregs_set,
        },

#ifdef CONFIG_SH_FPU
        [REGSET_FPU] = {
                .core_note_type = NT_PRFPREG,
                .n              = sizeof(struct user_fpu_struct) /
                                  sizeof(long long),
                .size           = sizeof(long long),
                .align          = sizeof(long long),
                .get            = fpregs_get,
                .set            = fpregs_set,
                .active         = fpregs_active,
        },
#endif
};

static const struct user_regset_view user_sh64_native_view = {
        .name           = "sh64",
        .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_sh64_native_view;
}

long arch_ptrace(struct task_struct *child, long request, long addr, long 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)
                        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))) {
                        tmp = get_fpu_long(child, addr - offsetof(struct user, fpu));
                } else if (addr == offsetof(struct user, u_fpvalid)) {
                        tmp = !!tsk_used_math(child);
                } else {
                        break;
                }
                ret = put_user(tmp, (unsigned long *)data);
                break;
        }

        case PTRACE_POKEUSR:
                /* write the word at location addr in the USER area. We must
                   disallow any changes to certain SR bits or u_fpvalid, since
                   this could crash the kernel or result in a security
                   loophole. */
                ret = -EIO;
                if ((addr & 3) || addr < 0)
                        break;

                if (addr < sizeof(struct pt_regs)) {
                        /* Ignore change of top 32 bits of SR */
                        if (addr == offsetof (struct pt_regs, sr)+4)
                        {
                                ret = 0;
                                break;
                        }
                        /* If lower 32 bits of SR, ignore non-user bits */
                        if (addr == offsetof (struct pt_regs, sr))
                        {
                                long cursr = get_stack_long(child, addr);
                                data &= ~(SR_MASK);
                                data |= (cursr & SR_MASK);
                        }
                        ret = put_stack_long(child, addr, data);
                }
                else if ((addr >= offsetof(struct user, fpu)) &&
                         (addr <  offsetof(struct user, u_fpvalid))) {
                        ret = put_fpu_long(child, addr - offsetof(struct user, fpu), data);
                }
                break;

        case PTRACE_GETREGS:
                return copy_regset_to_user(child, &user_sh64_native_view,
                                           REGSET_GENERAL,
                                           0, sizeof(struct pt_regs),
                                           (void __user *)data);
        case PTRACE_SETREGS:
                return copy_regset_from_user(child, &user_sh64_native_view,
                                             REGSET_GENERAL,
                                             0, sizeof(struct pt_regs),
                                             (const void __user *)data);
#ifdef CONFIG_SH_FPU
        case PTRACE_GETFPREGS:
                return copy_regset_to_user(child, &user_sh64_native_view,
                                           REGSET_FPU,
                                           0, sizeof(struct user_fpu_struct),
                                           (void __user *)data);
        case PTRACE_SETFPREGS:
                return copy_regset_from_user(child, &user_sh64_native_view,
                                             REGSET_FPU,
                                             0, sizeof(struct user_fpu_struct),
                                             (const void __user *)data);
#endif
        default:
                ret = ptrace_request(child, request, addr, data);
                break;
        }

        return ret;
}

asmlinkage int sh64_ptrace(long request, long pid, long addr, long data)
{
#define WPC_DBRMODE 0x0d104008
        static int first_call = 1;

        lock_kernel();
        if (first_call) {
                /* Set WPC.DBRMODE to 0.  This makes all debug events get
                 * delivered through RESVEC, i.e. into the handlers in entry.S.
                 * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
                 * would normally be left set to 1, which makes debug events get
                 * delivered through DBRVEC, i.e. into the remote gdb's
                 * handlers.  This prevents ptrace getting them, and confuses
                 * the remote gdb.) */
                printk("DBRMODE set to 0 to permit native debugging\n");
                poke_real_address_q(WPC_DBRMODE, 0);
                first_call = 0;
        }
        unlock_kernel();

        return sys_ptrace(request, pid, addr, data);
}

static inline int audit_arch(void)
{
        int arch = EM_SH;

#ifdef CONFIG_64BIT
        arch |= __AUDIT_ARCH_64BIT;
#endif
#ifdef CONFIG_CPU_LITTLE_ENDIAN
        arch |= __AUDIT_ARCH_LE;
#endif

        return arch;
}

asmlinkage long long do_syscall_trace_enter(struct pt_regs *regs)
{
        long long ret = 0;

        secure_computing(regs->regs[9]);

        if (test_thread_flag(TIF_SYSCALL_TRACE) &&
            tracehook_report_syscall_entry(regs))
                /*
                 * Tracing decided this syscall should not happen.
                 * We'll return a bogus call number to get an ENOSYS
                 * error, but leave the original number in regs->regs[0].
                 */
                ret = -1LL;

        if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
                trace_sys_enter(regs, regs->regs[9]);

        if (unlikely(current->audit_context))
                audit_syscall_entry(audit_arch(), regs->regs[1],
                                    regs->regs[2], regs->regs[3],
                                    regs->regs[4], regs->regs[5]);

        return ret ?: regs->regs[9];
}

asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
{
        if (unlikely(current->audit_context))
                audit_syscall_exit(AUDITSC_RESULT(regs->regs[9]),
                                   regs->regs[9]);

        if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
                trace_sys_exit(regs, regs->regs[9]);

        if (test_thread_flag(TIF_SYSCALL_TRACE))
                tracehook_report_syscall_exit(regs, 0);
}

/* Called with interrupts disabled */
asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
{
        /* This is called after a single step exception (DEBUGSS).
           There is no need to change the PC, as it is a post-execution
           exception, as entry.S does not do anything to the PC for DEBUGSS.
           We need to clear the Single Step setting in SR to avoid
           continually stepping. */
        local_irq_enable();
        regs->sr &= ~SR_SSTEP;
        force_sig(SIGTRAP, current);
}

/* Called with interrupts disabled */
asmlinkage void do_software_break_point(unsigned long long vec,
                                        struct pt_regs *regs)
{
        /* We need to forward step the PC, to counteract the backstep done
           in signal.c. */
        local_irq_enable();
        force_sig(SIGTRAP, current);
        regs->pc += 4;
}

/*
 * 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);
}