// SPDX-License-Identifier: GPL-2.0-or-later

#include <linux/regset.h>
#include <linux/elf.h>

#include <asm/switch_to.h>

#include "ptrace-decl.h"

/*
 * Get/set all the altivec registers vr0..vr31, vscr, vrsave, in one go.
 * The transfer totals 34 quadword.  Quadwords 0-31 contain the
 * corresponding vector registers.  Quadword 32 contains the vscr as the
 * last word (offset 12) within that quadword.  Quadword 33 contains the
 * vrsave as the first word (offset 0) within the quadword.
 *
 * This definition of the VMX state is compatible with the current PPC32
 * ptrace interface.  This allows signal handling and ptrace to use the
 * same structures.  This also simplifies the implementation of a bi-arch
 * (combined (32- and 64-bit) gdb.
 */

int vr_active(struct task_struct *target, const struct user_regset *regset)
{
        flush_altivec_to_thread(target);
        return target->thread.used_vr ? regset->n : 0;
}

/*
 * Regardless of transactions, 'vr_state' holds the current running
 * value of all the VMX registers and 'ckvr_state' holds the last
 * checkpointed value of all the VMX registers for the current
 * transaction to fall back on in case it aborts.
 *
 * Userspace interface buffer layout:
 *
 * struct data {
 *      vector128       vr[32];
 *      vector128       vscr;
 *      vector128       vrsave;
 * };
 */
int vr_get(struct task_struct *target, const struct user_regset *regset,
           struct membuf to)
{
        union {
                elf_vrreg_t reg;
                u32 word;
        } vrsave;

        flush_altivec_to_thread(target);

        BUILD_BUG_ON(offsetof(struct thread_vr_state, vscr) !=
                     offsetof(struct thread_vr_state, vr[32]));

        membuf_write(&to, &target->thread.vr_state, 33 * sizeof(vector128));
        /*
         * Copy out only the low-order word of vrsave.
         */
        memset(&vrsave, 0, sizeof(vrsave));
        vrsave.word = target->thread.vrsave;
        return membuf_write(&to, &vrsave, sizeof(vrsave));
}

/*
 * Regardless of transactions, 'vr_state' holds the current running
 * value of all the VMX registers and 'ckvr_state' holds the last
 * checkpointed value of all the VMX registers for the current
 * transaction to fall back on in case it aborts.
 *
 * Userspace interface buffer layout:
 *
 * struct data {
 *      vector128       vr[32];
 *      vector128       vscr;
 *      vector128       vrsave;
 * };
 */
int vr_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;

        flush_altivec_to_thread(target);

        BUILD_BUG_ON(offsetof(struct thread_vr_state, vscr) !=
                     offsetof(struct thread_vr_state, vr[32]));

        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                 &target->thread.vr_state, 0,
                                 33 * sizeof(vector128));
        if (!ret && count > 0) {
                /*
                 * We use only the first word of vrsave.
                 */
                int start, end;
                union {
                        elf_vrreg_t reg;
                        u32 word;
                } vrsave;
                memset(&vrsave, 0, sizeof(vrsave));

                vrsave.word = target->thread.vrsave;

                start = 33 * sizeof(vector128);
                end = start + sizeof(vrsave);
                ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &vrsave,
                                         start, end);
                if (!ret)
                        target->thread.vrsave = vrsave.word;
        }

        return ret;
}