// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * CoProcessor (SPU/AFU) mm fault handler
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2007
 *
 * Author: Arnd Bergmann <arndb@de.ibm.com>
 * Author: Jeremy Kerr <jk@ozlabs.org>
 */
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/export.h>
#include <asm/reg.h>
#include <asm/copro.h>

/*
 * This ought to be kept in sync with the powerpc specific do_page_fault
 * function. Currently, there are a few corner cases that we haven't had
 * to handle fortunately.
 */
int copro_handle_mm_fault(struct mm_struct *mm, unsigned long ea,
                unsigned long dsisr, vm_fault_t *flt)
{
        struct vm_area_struct *vma;
        unsigned long is_write;
        int ret;

        if (mm == NULL)
                return -EFAULT;

        if (mm->pgd == NULL)
                return -EFAULT;

        vma = lock_mm_and_find_vma(mm, ea, NULL);
        if (!vma)
                return -EFAULT;

        ret = -EFAULT;
        is_write = dsisr & DSISR_ISSTORE;
        if (is_write) {
                if (!(vma->vm_flags & VM_WRITE))
                        goto out_unlock;
        } else {
                if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
                        goto out_unlock;
                /*
                 * PROT_NONE is covered by the VMA check above.
                 * and hash should get a NOHPTE fault instead of
                 * a PROTFAULT in case fixup is needed for things
                 * like autonuma.
                 */
                if (!radix_enabled())
                        WARN_ON_ONCE(dsisr & DSISR_PROTFAULT);
        }

        ret = 0;
        *flt = handle_mm_fault(vma, ea, is_write ? FAULT_FLAG_WRITE : 0, NULL);

        /* The fault is fully completed (including releasing mmap lock) */
        if (*flt & VM_FAULT_COMPLETED)
                return 0;

        if (unlikely(*flt & VM_FAULT_ERROR)) {
                if (*flt & VM_FAULT_OOM) {
                        ret = -ENOMEM;
                        goto out_unlock;
                } else if (*flt & (VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV)) {
                        ret = -EFAULT;
                        goto out_unlock;
                }
                BUG();
        }

out_unlock:
        mmap_read_unlock(mm);
        return ret;
}
EXPORT_SYMBOL_GPL(copro_handle_mm_fault);

#ifdef CONFIG_PPC_64S_HASH_MMU
int copro_calculate_slb(struct mm_struct *mm, u64 ea, struct copro_slb *slb)
{
        u64 vsid, vsidkey;
        int psize, ssize;

        switch (get_region_id(ea)) {
        case USER_REGION_ID:
                pr_devel("%s: 0x%llx -- USER_REGION_ID\n", __func__, ea);
                if (mm == NULL)
                        return 1;
                psize = get_slice_psize(mm, ea);
                ssize = user_segment_size(ea);
                vsid = get_user_vsid(&mm->context, ea, ssize);
                vsidkey = SLB_VSID_USER;
                break;
        case VMALLOC_REGION_ID:
                pr_devel("%s: 0x%llx -- VMALLOC_REGION_ID\n", __func__, ea);
                psize = mmu_vmalloc_psize;
                ssize = mmu_kernel_ssize;
                vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
                vsidkey = SLB_VSID_KERNEL;
                break;
        case IO_REGION_ID:
                pr_devel("%s: 0x%llx -- IO_REGION_ID\n", __func__, ea);
                psize = mmu_io_psize;
                ssize = mmu_kernel_ssize;
                vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
                vsidkey = SLB_VSID_KERNEL;
                break;
        case LINEAR_MAP_REGION_ID:
                pr_devel("%s: 0x%llx -- LINEAR_MAP_REGION_ID\n", __func__, ea);
                psize = mmu_linear_psize;
                ssize = mmu_kernel_ssize;
                vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
                vsidkey = SLB_VSID_KERNEL;
                break;
        default:
                pr_debug("%s: invalid region access at %016llx\n", __func__, ea);
                return 1;
        }
        /* Bad address */
        if (!vsid)
                return 1;

        vsid = (vsid << slb_vsid_shift(ssize)) | vsidkey;

        vsid |= mmu_psize_defs[psize].sllp |
                ((ssize == MMU_SEGSIZE_1T) ? SLB_VSID_B_1T : 0);

        slb->esid = (ea & (ssize == MMU_SEGSIZE_1T ? ESID_MASK_1T : ESID_MASK)) | SLB_ESID_V;
        slb->vsid = vsid;

        return 0;
}
EXPORT_SYMBOL_GPL(copro_calculate_slb);
#endif