// SPDX-License-Identifier: GPL-2.0
/*
 *  Ptrace user space interface.
 *
 *    Copyright IBM Corp. 1999, 2010
 *    Author(s): Denis Joseph Barrow
 *               Martin Schwidefsky (schwidefsky@de.ibm.com)
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/cpufeature.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/audit.h>
#include <linux/signal.h>
#include <linux/elf.h>
#include <linux/regset.h>
#include <linux/seccomp.h>
#include <trace/syscall.h>
#include <asm/guarded_storage.h>
#include <asm/access-regs.h>
#include <asm/page.h>
#include <linux/uaccess.h>
#include <asm/unistd.h>
#include <asm/runtime_instr.h>
#include <asm/facility.h>
#include <asm/machine.h>
#include <asm/ptrace.h>
#include <asm/rwonce.h>
#include <asm/fpu.h>

#include "entry.h"

void update_cr_regs(struct task_struct *task)
{
        struct pt_regs *regs = task_pt_regs(task);
        struct thread_struct *thread = &task->thread;
        union ctlreg0 cr0_old, cr0_new;
        union ctlreg2 cr2_old, cr2_new;
        int cr0_changed, cr2_changed;
        union {
                struct ctlreg regs[3];
                struct {
                        struct ctlreg control;
                        struct ctlreg start;
                        struct ctlreg end;
                };
        } old, new;

        local_ctl_store(0, &cr0_old.reg);
        local_ctl_store(2, &cr2_old.reg);
        cr0_new = cr0_old;
        cr2_new = cr2_old;
        /* Take care of the enable/disable of transactional execution. */
        if (machine_has_tx()) {
                /* Set or clear transaction execution TXC bit 8. */
                cr0_new.tcx = 1;
                if (task->thread.per_flags & PER_FLAG_NO_TE)
                        cr0_new.tcx = 0;
                /* Set or clear transaction execution TDC bits 62 and 63. */
                cr2_new.tdc = 0;
                if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND) {
                        if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND_TEND)
                                cr2_new.tdc = 1;
                        else
                                cr2_new.tdc = 2;
                }
        }
        /* Take care of enable/disable of guarded storage. */
        if (cpu_has_gs()) {
                cr2_new.gse = 0;
                if (task->thread.gs_cb)
                        cr2_new.gse = 1;
        }
        /* Load control register 0/2 iff changed */
        cr0_changed = cr0_new.val != cr0_old.val;
        cr2_changed = cr2_new.val != cr2_old.val;
        if (cr0_changed)
                local_ctl_load(0, &cr0_new.reg);
        if (cr2_changed)
                local_ctl_load(2, &cr2_new.reg);
        /* Copy user specified PER registers */
        new.control.val = thread->per_user.control;
        new.start.val = thread->per_user.start;
        new.end.val = thread->per_user.end;

        /* merge TIF_SINGLE_STEP into user specified PER registers. */
        if (test_tsk_thread_flag(task, TIF_SINGLE_STEP) ||
            test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP)) {
                if (test_tsk_thread_flag(task, TIF_BLOCK_STEP))
                        new.control.val |= PER_EVENT_BRANCH;
                else
                        new.control.val |= PER_EVENT_IFETCH;
                new.control.val |= PER_CONTROL_SUSPENSION;
                new.control.val |= PER_EVENT_TRANSACTION_END;
                if (test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP))
                        new.control.val |= PER_EVENT_IFETCH;
                new.start.val = 0;
                new.end.val = -1UL;
        }

        /* Take care of the PER enablement bit in the PSW. */
        if (!(new.control.val & PER_EVENT_MASK)) {
                regs->psw.mask &= ~PSW_MASK_PER;
                return;
        }
        regs->psw.mask |= PSW_MASK_PER;
        __local_ctl_store(9, 11, old.regs);
        if (memcmp(&new, &old, sizeof(struct per_regs)) != 0)
                __local_ctl_load(9, 11, new.regs);
}

void user_enable_single_step(struct task_struct *task)
{
        clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
        set_tsk_thread_flag(task, TIF_SINGLE_STEP);
}

void user_disable_single_step(struct task_struct *task)
{
        clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
        clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
}

void user_enable_block_step(struct task_struct *task)
{
        set_tsk_thread_flag(task, TIF_SINGLE_STEP);
        set_tsk_thread_flag(task, TIF_BLOCK_STEP);
}

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Clear all debugging related fields.
 */
void ptrace_disable(struct task_struct *task)
{
        memset(&task->thread.per_user, 0, sizeof(task->thread.per_user));
        memset(&task->thread.per_event, 0, sizeof(task->thread.per_event));
        clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
        clear_tsk_thread_flag(task, TIF_PER_TRAP);
        task->thread.per_flags = 0;
}

#define __ADDR_MASK 7

static inline unsigned long __peek_user_per(struct task_struct *child,
                                            addr_t addr)
{
        if (addr == offsetof(struct per_struct_kernel, cr9))
                /* Control bits of the active per set. */
                return test_thread_flag(TIF_SINGLE_STEP) ?
                        PER_EVENT_IFETCH : child->thread.per_user.control;
        else if (addr == offsetof(struct per_struct_kernel, cr10))
                /* Start address of the active per set. */
                return test_thread_flag(TIF_SINGLE_STEP) ?
                        0 : child->thread.per_user.start;
        else if (addr == offsetof(struct per_struct_kernel, cr11))
                /* End address of the active per set. */
                return test_thread_flag(TIF_SINGLE_STEP) ?
                        -1UL : child->thread.per_user.end;
        else if (addr == offsetof(struct per_struct_kernel, bits))
                /* Single-step bit. */
                return test_thread_flag(TIF_SINGLE_STEP) ?
                        (1UL << (BITS_PER_LONG - 1)) : 0;
        else if (addr == offsetof(struct per_struct_kernel, starting_addr))
                /* Start address of the user specified per set. */
                return child->thread.per_user.start;
        else if (addr == offsetof(struct per_struct_kernel, ending_addr))
                /* End address of the user specified per set. */
                return child->thread.per_user.end;
        else if (addr == offsetof(struct per_struct_kernel, perc_atmid))
                /* PER code, ATMID and AI of the last PER trap */
                return (unsigned long)
                        child->thread.per_event.cause << (BITS_PER_LONG - 16);
        else if (addr == offsetof(struct per_struct_kernel, address))
                /* Address of the last PER trap */
                return child->thread.per_event.address;
        else if (addr == offsetof(struct per_struct_kernel, access_id))
                /* Access id of the last PER trap */
                return (unsigned long)
                        child->thread.per_event.paid << (BITS_PER_LONG - 8);
        return 0;
}

/*
 * Read the word at offset addr from the user area of a process. The
 * trouble here is that the information is littered over different
 * locations. The process registers are found on the kernel stack,
 * the floating point stuff and the trace settings are stored in
 * the task structure. In addition the different structures in
 * struct user contain pad bytes that should be read as zeroes.
 * Lovely...
 */
static unsigned long __peek_user(struct task_struct *child, addr_t addr)
{
        addr_t offset, tmp;

        if (addr < offsetof(struct user, regs.acrs)) {
                /*
                 * psw and gprs are stored on the stack
                 */
                tmp = *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr);
                if (addr == offsetof(struct user, regs.psw.mask)) {
                        /* Return a clean psw mask. */
                        tmp &= PSW_MASK_USER | PSW_MASK_RI;
                        tmp |= PSW_USER_BITS;
                }

        } else if (addr < offsetof(struct user, regs.orig_gpr2)) {
                /*
                 * access registers are stored in the thread structure
                 */
                offset = addr - offsetof(struct user, regs.acrs);
                /*
                 * Very special case: old & broken 64 bit gdb reading
                 * from acrs[15]. Result is a 64 bit value. Read the
                 * 32 bit acrs[15] value and shift it by 32. Sick...
                 */
                if (addr == offsetof(struct user, regs.acrs[15]))
                        tmp = ((unsigned long) child->thread.acrs[15]) << 32;
                else
                        tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset);

        } else if (addr == offsetof(struct user, regs.orig_gpr2)) {
                /*
                 * orig_gpr2 is stored on the kernel stack
                 */
                tmp = (addr_t) task_pt_regs(child)->orig_gpr2;

        } else if (addr < offsetof(struct user, regs.fp_regs)) {
                /*
                 * prevent reads of padding hole between
                 * orig_gpr2 and fp_regs on s390.
                 */
                tmp = 0;

        } else if (addr == offsetof(struct user, regs.fp_regs.fpc)) {
                /*
                 * floating point control reg. is in the thread structure
                 */
                tmp = child->thread.ufpu.fpc;
                tmp <<= BITS_PER_LONG - 32;

        } else if (addr < offsetof(struct user, regs.fp_regs) + sizeof(s390_fp_regs)) {
                /*
                 * floating point regs. are in the child->thread.ufpu.vxrs array
                 */
                offset = addr - offsetof(struct user, regs.fp_regs.fprs);
                tmp = *(addr_t *)((addr_t)child->thread.ufpu.vxrs + 2 * offset);
        } else if (addr < offsetof(struct user, regs.per_info) + sizeof(per_struct)) {
                /*
                 * Handle access to the per_info structure.
                 */
                addr -= offsetof(struct user, regs.per_info);
                tmp = __peek_user_per(child, addr);

        } else
                tmp = 0;

        return tmp;
}

static int
peek_user(struct task_struct *child, addr_t addr, addr_t data)
{
        addr_t tmp, mask;

        /*
         * Stupid gdb peeks/pokes the access registers in 64 bit with
         * an alignment of 4. Programmers from hell...
         */
        mask = __ADDR_MASK;
        if (addr >= offsetof(struct user, regs.acrs) &&
            addr < offsetof(struct user, regs.orig_gpr2))
                mask = 3;
        if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
                return -EIO;

        tmp = __peek_user(child, addr);
        return put_user(tmp, (addr_t __user *) data);
}

static inline void __poke_user_per(struct task_struct *child,
                                   addr_t addr, addr_t data)
{
        /*
         * There are only three fields in the per_info struct that the
         * debugger user can write to.
         * 1) cr9: the debugger wants to set a new PER event mask
         * 2) starting_addr: the debugger wants to set a new starting
         *    address to use with the PER event mask.
         * 3) ending_addr: the debugger wants to set a new ending
         *    address to use with the PER event mask.
         * The user specified PER event mask and the start and end
         * addresses are used only if single stepping is not in effect.
         * Writes to any other field in per_info are ignored.
         */
        if (addr == offsetof(struct per_struct_kernel, cr9))
                /* PER event mask of the user specified per set. */
                child->thread.per_user.control =
                        data & (PER_EVENT_MASK | PER_CONTROL_MASK);
        else if (addr == offsetof(struct per_struct_kernel, starting_addr))
                /* Starting address of the user specified per set. */
                child->thread.per_user.start = data;
        else if (addr == offsetof(struct per_struct_kernel, ending_addr))
                /* Ending address of the user specified per set. */
                child->thread.per_user.end = data;
}

/*
 * Write a word to the user area of a process at location addr. This
 * operation does have an additional problem compared to peek_user.
 * Stores to the program status word and on the floating point
 * control register needs to get checked for validity.
 */
static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
{
        addr_t offset;


        if (addr < offsetof(struct user, regs.acrs)) {
                struct pt_regs *regs = task_pt_regs(child);
                /*
                 * psw and gprs are stored on the stack
                 */
                if (addr == offsetof(struct user, regs.psw.mask)) {
                        unsigned long mask = PSW_MASK_USER;

                        mask |= is_ri_task(child) ? PSW_MASK_RI : 0;
                        if ((data ^ PSW_USER_BITS) & ~mask)
                                /* Invalid psw mask. */
                                return -EINVAL;
                        if ((data & PSW_MASK_ASC) == PSW_ASC_HOME)
                                /* Invalid address-space-control bits */
                                return -EINVAL;
                        if ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA))
                                /* Invalid addressing mode bits */
                                return -EINVAL;
                }

                if (test_pt_regs_flag(regs, PIF_SYSCALL) &&
                        addr == offsetof(struct user, regs.gprs[2])) {
                        struct pt_regs *regs = task_pt_regs(child);

                        regs->int_code = 0x20000 | (data & 0xffff);
                }
                *(addr_t *)((addr_t) &regs->psw + addr) = data;
        } else if (addr < offsetof(struct user, regs.orig_gpr2)) {
                /*
                 * access registers are stored in the thread structure
                 */
                offset = addr - offsetof(struct user, regs.acrs);
                /*
                 * Very special case: old & broken 64 bit gdb writing
                 * to acrs[15] with a 64 bit value. Ignore the lower
                 * half of the value and write the upper 32 bit to
                 * acrs[15]. Sick...
                 */
                if (addr == offsetof(struct user, regs.acrs[15]))
                        child->thread.acrs[15] = (unsigned int) (data >> 32);
                else
                        *(addr_t *)((addr_t) &child->thread.acrs + offset) = data;

        } else if (addr == offsetof(struct user, regs.orig_gpr2)) {
                /*
                 * orig_gpr2 is stored on the kernel stack
                 */
                task_pt_regs(child)->orig_gpr2 = data;

        } else if (addr < offsetof(struct user, regs.fp_regs)) {
                /*
                 * prevent writes of padding hole between
                 * orig_gpr2 and fp_regs on s390.
                 */
                return 0;

        } else if (addr == offsetof(struct user, regs.fp_regs.fpc)) {
                /*
                 * floating point control reg. is in the thread structure
                 */
                if ((unsigned int)data != 0)
                        return -EINVAL;
                child->thread.ufpu.fpc = data >> (BITS_PER_LONG - 32);

        } else if (addr < offsetof(struct user, regs.fp_regs) + sizeof(s390_fp_regs)) {
                /*
                 * floating point regs. are in the child->thread.ufpu.vxrs array
                 */
                offset = addr - offsetof(struct user, regs.fp_regs.fprs);
                *(addr_t *)((addr_t)child->thread.ufpu.vxrs + 2 * offset) = data;
        } else if (addr < offsetof(struct user, regs.per_info) + sizeof(per_struct)) {
                /*
                 * Handle access to the per_info structure.
                 */
                addr -= offsetof(struct user, regs.per_info);
                __poke_user_per(child, addr, data);

        }

        return 0;
}

static int poke_user(struct task_struct *child, addr_t addr, addr_t data)
{
        addr_t mask;

        /*
         * Stupid gdb peeks/pokes the access registers in 64 bit with
         * an alignment of 4. Programmers from hell indeed...
         */
        mask = __ADDR_MASK;
        if (addr >= offsetof(struct user, regs.acrs) &&
            addr < offsetof(struct user, regs.orig_gpr2))
                mask = 3;
        if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
                return -EIO;

        return __poke_user(child, addr, data);
}

long arch_ptrace(struct task_struct *child, long request,
                 unsigned long addr, unsigned long data)
{
        ptrace_area parea; 
        int copied, ret;

        switch (request) {
        case PTRACE_PEEKUSR:
                /* read the word at location addr in the USER area. */
                return peek_user(child, addr, data);

        case PTRACE_POKEUSR:
                /* write the word at location addr in the USER area */
                return poke_user(child, addr, data);

        case PTRACE_PEEKUSR_AREA:
        case PTRACE_POKEUSR_AREA:
                if (copy_from_user(&parea, (void __force __user *) addr,
                                                        sizeof(parea)))
                        return -EFAULT;
                addr = parea.kernel_addr;
                data = parea.process_addr;
                copied = 0;
                while (copied < parea.len) {
                        if (request == PTRACE_PEEKUSR_AREA)
                                ret = peek_user(child, addr, data);
                        else {
                                addr_t utmp;
                                if (get_user(utmp,
                                             (addr_t __force __user *) data))
                                        return -EFAULT;
                                ret = poke_user(child, addr, utmp);
                        }
                        if (ret)
                                return ret;
                        addr += sizeof(unsigned long);
                        data += sizeof(unsigned long);
                        copied += sizeof(unsigned long);
                }
                return 0;
        case PTRACE_GET_LAST_BREAK:
                return put_user(child->thread.last_break, (unsigned long __user *)data);
        case PTRACE_ENABLE_TE:
                if (!machine_has_tx())
                        return -EIO;
                child->thread.per_flags &= ~PER_FLAG_NO_TE;
                return 0;
        case PTRACE_DISABLE_TE:
                if (!machine_has_tx())
                        return -EIO;
                child->thread.per_flags |= PER_FLAG_NO_TE;
                child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND;
                return 0;
        case PTRACE_TE_ABORT_RAND:
                if (!machine_has_tx() || (child->thread.per_flags & PER_FLAG_NO_TE))
                        return -EIO;
                switch (data) {
                case 0UL:
                        child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND;
                        break;
                case 1UL:
                        child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND;
                        child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND_TEND;
                        break;
                case 2UL:
                        child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND;
                        child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND_TEND;
                        break;
                default:
                        return -EINVAL;
                }
                return 0;
        default:
                return ptrace_request(child, request, addr, data);
        }
}

/*
 * user_regset definitions.
 */

static int s390_regs_get(struct task_struct *target,
                         const struct user_regset *regset,
                         struct membuf to)
{
        unsigned pos;
        if (target == current)
                save_access_regs(target->thread.acrs);

        for (pos = 0; pos < sizeof(s390_regs); pos += sizeof(long))
                membuf_store(&to, __peek_user(target, pos));
        return 0;
}

static int s390_regs_set(struct task_struct *target,
                         const struct user_regset *regset,
                         unsigned int pos, unsigned int count,
                         const void *kbuf, const void __user *ubuf)
{
        int rc = 0;

        if (target == current)
                save_access_regs(target->thread.acrs);

        if (kbuf) {
                const unsigned long *k = kbuf;
                while (count > 0 && !rc) {
                        rc = __poke_user(target, pos, *k++);
                        count -= sizeof(*k);
                        pos += sizeof(*k);
                }
        } else {
                const unsigned long  __user *u = ubuf;
                while (count > 0 && !rc) {
                        unsigned long word;
                        rc = __get_user(word, u++);
                        if (rc)
                                break;
                        rc = __poke_user(target, pos, word);
                        count -= sizeof(*u);
                        pos += sizeof(*u);
                }
        }

        if (rc == 0 && target == current)
                restore_access_regs(target->thread.acrs);

        return rc;
}

static int s390_fpregs_get(struct task_struct *target,
                           const struct user_regset *regset,
                           struct membuf to)
{
        _s390_fp_regs fp_regs;

        if (target == current)
                save_user_fpu_regs();

        fp_regs.fpc = target->thread.ufpu.fpc;
        fpregs_store(&fp_regs, &target->thread.ufpu);

        return membuf_write(&to, &fp_regs, sizeof(fp_regs));
}

static int s390_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 rc = 0;
        freg_t fprs[__NUM_FPRS];

        if (target == current)
                save_user_fpu_regs();
        convert_vx_to_fp(fprs, target->thread.ufpu.vxrs);
        if (count > 0 && pos < offsetof(s390_fp_regs, fprs)) {
                u32 ufpc[2] = { target->thread.ufpu.fpc, 0 };
                rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ufpc,
                                        0, offsetof(s390_fp_regs, fprs));
                if (rc)
                        return rc;
                if (ufpc[1] != 0)
                        return -EINVAL;
                target->thread.ufpu.fpc = ufpc[0];
        }

        if (rc == 0 && count > 0)
                rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                        fprs, offsetof(s390_fp_regs, fprs), -1);
        if (rc)
                return rc;
        convert_fp_to_vx(target->thread.ufpu.vxrs, fprs);
        return rc;
}

static int s390_last_break_get(struct task_struct *target,
                               const struct user_regset *regset,
                               struct membuf to)
{
        return membuf_store(&to, target->thread.last_break);
}

static int s390_last_break_set(struct task_struct *target,
                               const struct user_regset *regset,
                               unsigned int pos, unsigned int count,
                               const void *kbuf, const void __user *ubuf)
{
        return 0;
}

static int s390_tdb_get(struct task_struct *target,
                        const struct user_regset *regset,
                        struct membuf to)
{
        struct pt_regs *regs = task_pt_regs(target);
        size_t size;

        if (!(regs->int_code & 0x200))
                return -ENODATA;
        size = sizeof(target->thread.trap_tdb.data);
        return membuf_write(&to, target->thread.trap_tdb.data, size);
}

static int s390_tdb_set(struct task_struct *target,
                        const struct user_regset *regset,
                        unsigned int pos, unsigned int count,
                        const void *kbuf, const void __user *ubuf)
{
        return 0;
}

static int s390_vxrs_low_get(struct task_struct *target,
                             const struct user_regset *regset,
                             struct membuf to)
{
        __u64 vxrs[__NUM_VXRS_LOW];
        int i;

        if (!cpu_has_vx())
                return -ENODEV;
        if (target == current)
                save_user_fpu_regs();
        for (i = 0; i < __NUM_VXRS_LOW; i++)
                vxrs[i] = target->thread.ufpu.vxrs[i].low;
        return membuf_write(&to, vxrs, sizeof(vxrs));
}

static int s390_vxrs_low_set(struct task_struct *target,
                             const struct user_regset *regset,
                             unsigned int pos, unsigned int count,
                             const void *kbuf, const void __user *ubuf)
{
        __u64 vxrs[__NUM_VXRS_LOW];
        int i, rc;

        if (!cpu_has_vx())
                return -ENODEV;
        if (target == current)
                save_user_fpu_regs();

        for (i = 0; i < __NUM_VXRS_LOW; i++)
                vxrs[i] = target->thread.ufpu.vxrs[i].low;

        rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1);
        if (rc == 0)
                for (i = 0; i < __NUM_VXRS_LOW; i++)
                        target->thread.ufpu.vxrs[i].low = vxrs[i];

        return rc;
}

static int s390_vxrs_high_get(struct task_struct *target,
                              const struct user_regset *regset,
                              struct membuf to)
{
        if (!cpu_has_vx())
                return -ENODEV;
        if (target == current)
                save_user_fpu_regs();
        return membuf_write(&to, target->thread.ufpu.vxrs + __NUM_VXRS_LOW,
                            __NUM_VXRS_HIGH * sizeof(__vector128));
}

static int s390_vxrs_high_set(struct task_struct *target,
                              const struct user_regset *regset,
                              unsigned int pos, unsigned int count,
                              const void *kbuf, const void __user *ubuf)
{
        int rc;

        if (!cpu_has_vx())
                return -ENODEV;
        if (target == current)
                save_user_fpu_regs();

        rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                target->thread.ufpu.vxrs + __NUM_VXRS_LOW, 0, -1);
        return rc;
}

static int s390_system_call_get(struct task_struct *target,
                                const struct user_regset *regset,
                                struct membuf to)
{
        return membuf_store(&to, target->thread.system_call);
}

static int s390_system_call_set(struct task_struct *target,
                                const struct user_regset *regset,
                                unsigned int pos, unsigned int count,
                                const void *kbuf, const void __user *ubuf)
{
        unsigned int *data = &target->thread.system_call;
        return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                  data, 0, sizeof(unsigned int));
}

static int s390_gs_cb_get(struct task_struct *target,
                          const struct user_regset *regset,
                          struct membuf to)
{
        struct gs_cb *data = target->thread.gs_cb;

        if (!cpu_has_gs())
                return -ENODEV;
        if (!data)
                return -ENODATA;
        if (target == current)
                save_gs_cb(data);
        return membuf_write(&to, data, sizeof(struct gs_cb));
}

static int s390_gs_cb_set(struct task_struct *target,
                          const struct user_regset *regset,
                          unsigned int pos, unsigned int count,
                          const void *kbuf, const void __user *ubuf)
{
        struct gs_cb gs_cb = { }, *data = NULL;
        int rc;

        if (!cpu_has_gs())
                return -ENODEV;
        if (!target->thread.gs_cb) {
                data = kzalloc_obj(*data);
                if (!data)
                        return -ENOMEM;
        }
        if (!target->thread.gs_cb)
                gs_cb.gsd = 25;
        else if (target == current)
                save_gs_cb(&gs_cb);
        else
                gs_cb = *target->thread.gs_cb;
        rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                &gs_cb, 0, sizeof(gs_cb));
        if (rc) {
                kfree(data);
                return -EFAULT;
        }
        preempt_disable();
        if (!target->thread.gs_cb)
                target->thread.gs_cb = data;
        *target->thread.gs_cb = gs_cb;
        if (target == current) {
                local_ctl_set_bit(2, CR2_GUARDED_STORAGE_BIT);
                restore_gs_cb(target->thread.gs_cb);
        }
        preempt_enable();
        return rc;
}

static int s390_gs_bc_get(struct task_struct *target,
                          const struct user_regset *regset,
                          struct membuf to)
{
        struct gs_cb *data = target->thread.gs_bc_cb;

        if (!cpu_has_gs())
                return -ENODEV;
        if (!data)
                return -ENODATA;
        return membuf_write(&to, data, sizeof(struct gs_cb));
}

static int s390_gs_bc_set(struct task_struct *target,
                          const struct user_regset *regset,
                          unsigned int pos, unsigned int count,
                          const void *kbuf, const void __user *ubuf)
{
        struct gs_cb *data = target->thread.gs_bc_cb;

        if (!cpu_has_gs())
                return -ENODEV;
        if (!data) {
                data = kzalloc_obj(*data);
                if (!data)
                        return -ENOMEM;
                target->thread.gs_bc_cb = data;
        }
        return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                  data, 0, sizeof(struct gs_cb));
}

static bool is_ri_cb_valid(struct runtime_instr_cb *cb)
{
        return (cb->rca & 0x1f) == 0 &&
                (cb->roa & 0xfff) == 0 &&
                (cb->rla & 0xfff) == 0xfff &&
                cb->s == 1 &&
                cb->k == 1 &&
                cb->h == 0 &&
                cb->reserved1 == 0 &&
                cb->ps == 1 &&
                cb->qs == 0 &&
                cb->pc == 1 &&
                cb->qc == 0 &&
                cb->reserved2 == 0 &&
                cb->reserved3 == 0 &&
                cb->reserved4 == 0 &&
                cb->reserved5 == 0 &&
                cb->reserved6 == 0 &&
                cb->reserved7 == 0 &&
                cb->reserved8 == 0 &&
                cb->rla >= cb->roa &&
                cb->rca >= cb->roa &&
                cb->rca <= cb->rla+1 &&
                cb->m < 3;
}

static int s390_runtime_instr_get(struct task_struct *target,
                                const struct user_regset *regset,
                                struct membuf to)
{
        struct runtime_instr_cb *data = target->thread.ri_cb;

        if (!test_facility(64))
                return -ENODEV;
        if (!data)
                return -ENODATA;

        return membuf_write(&to, data, sizeof(struct runtime_instr_cb));
}

static int s390_runtime_instr_set(struct task_struct *target,
                                  const struct user_regset *regset,
                                  unsigned int pos, unsigned int count,
                                  const void *kbuf, const void __user *ubuf)
{
        struct runtime_instr_cb ri_cb = { }, *data = NULL;
        int rc;

        if (!test_facility(64))
                return -ENODEV;

        if (!target->thread.ri_cb) {
                data = kzalloc_obj(*data);
                if (!data)
                        return -ENOMEM;
        }

        if (target->thread.ri_cb) {
                if (target == current)
                        store_runtime_instr_cb(&ri_cb);
                else
                        ri_cb = *target->thread.ri_cb;
        }

        rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                &ri_cb, 0, sizeof(struct runtime_instr_cb));
        if (rc) {
                kfree(data);
                return -EFAULT;
        }

        if (!is_ri_cb_valid(&ri_cb)) {
                kfree(data);
                return -EINVAL;
        }
        /*
         * Override access key in any case, since user space should
         * not be able to set it, nor should it care about it.
         */
        ri_cb.key = PAGE_DEFAULT_KEY >> 4;
        preempt_disable();
        if (!target->thread.ri_cb)
                target->thread.ri_cb = data;
        *target->thread.ri_cb = ri_cb;
        if (target == current)
                load_runtime_instr_cb(target->thread.ri_cb);
        preempt_enable();

        return 0;
}

static const struct user_regset s390_regsets[] = {
        {
                USER_REGSET_NOTE_TYPE(PRSTATUS),
                .n = sizeof(s390_regs) / sizeof(long),
                .size = sizeof(long),
                .align = sizeof(long),
                .regset_get = s390_regs_get,
                .set = s390_regs_set,
        },
        {
                USER_REGSET_NOTE_TYPE(PRFPREG),
                .n = sizeof(s390_fp_regs) / sizeof(long),
                .size = sizeof(long),
                .align = sizeof(long),
                .regset_get = s390_fpregs_get,
                .set = s390_fpregs_set,
        },
        {
                USER_REGSET_NOTE_TYPE(S390_SYSTEM_CALL),
                .n = 1,
                .size = sizeof(unsigned int),
                .align = sizeof(unsigned int),
                .regset_get = s390_system_call_get,
                .set = s390_system_call_set,
        },
        {
                USER_REGSET_NOTE_TYPE(S390_LAST_BREAK),
                .n = 1,
                .size = sizeof(long),
                .align = sizeof(long),
                .regset_get = s390_last_break_get,
                .set = s390_last_break_set,
        },
        {
                USER_REGSET_NOTE_TYPE(S390_TDB),
                .n = 1,
                .size = 256,
                .align = 1,
                .regset_get = s390_tdb_get,
                .set = s390_tdb_set,
        },
        {
                USER_REGSET_NOTE_TYPE(S390_VXRS_LOW),
                .n = __NUM_VXRS_LOW,
                .size = sizeof(__u64),
                .align = sizeof(__u64),
                .regset_get = s390_vxrs_low_get,
                .set = s390_vxrs_low_set,
        },
        {
                USER_REGSET_NOTE_TYPE(S390_VXRS_HIGH),
                .n = __NUM_VXRS_HIGH,
                .size = sizeof(__vector128),
                .align = sizeof(__vector128),
                .regset_get = s390_vxrs_high_get,
                .set = s390_vxrs_high_set,
        },
        {
                USER_REGSET_NOTE_TYPE(S390_GS_CB),
                .n = sizeof(struct gs_cb) / sizeof(__u64),
                .size = sizeof(__u64),
                .align = sizeof(__u64),
                .regset_get = s390_gs_cb_get,
                .set = s390_gs_cb_set,
        },
        {
                USER_REGSET_NOTE_TYPE(S390_GS_BC),
                .n = sizeof(struct gs_cb) / sizeof(__u64),
                .size = sizeof(__u64),
                .align = sizeof(__u64),
                .regset_get = s390_gs_bc_get,
                .set = s390_gs_bc_set,
        },
        {
                USER_REGSET_NOTE_TYPE(S390_RI_CB),
                .n = sizeof(struct runtime_instr_cb) / sizeof(__u64),
                .size = sizeof(__u64),
                .align = sizeof(__u64),
                .regset_get = s390_runtime_instr_get,
                .set = s390_runtime_instr_set,
        },
};

static const struct user_regset_view user_s390_view = {
        .name = "s390x",
        .e_machine = EM_S390,
        .regsets = s390_regsets,
        .n = ARRAY_SIZE(s390_regsets)
};

const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
        return &user_s390_view;
}

static const char *gpr_names[NUM_GPRS] = {
        "r0", "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",
        "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
};

int regs_query_register_offset(const char *name)
{
        unsigned long offset;

        if (!name || *name != 'r')
                return -EINVAL;
        if (kstrtoul(name + 1, 10, &offset))
                return -EINVAL;
        if (offset >= NUM_GPRS)
                return -EINVAL;
        return offset;
}

const char *regs_query_register_name(unsigned int offset)
{
        if (offset >= NUM_GPRS)
                return NULL;
        return gpr_names[offset];
}