arch/powerpc/mm/copro_fault.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * CoProcessor (SPU/AFU) mm fault handler
   4  *
   5  * (C) Copyright IBM Deutschland Entwicklung GmbH 2007
   6  *
   7  * Author: Arnd Bergmann <arndb@de.ibm.com>
   8  * Author: Jeremy Kerr <jk@ozlabs.org>
   9  */
  10 #include <linux/sched.h>
  11 #include <linux/mm.h>
  12 #include <linux/export.h>
  13 #include <asm/reg.h>
  14 #include <asm/copro.h>
  15
  16 /*
  17  * This ought to be kept in sync with the powerpc specific do_page_fault
  18  * function. Currently, there are a few corner cases that we haven't had
  19  * to handle fortunately.
  20  */
  21 int copro_handle_mm_fault(struct mm_struct *mm, unsigned long ea,
  22                 unsigned long dsisr, vm_fault_t *flt)
  23 {
  24         struct vm_area_struct *vma;
  25         unsigned long is_write;
  26         int ret;
  27
  28         if (mm == NULL)
  29                 return -EFAULT;
  30
  31         if (mm->pgd == NULL)
  32                 return -EFAULT;
  33
  34         vma = lock_mm_and_find_vma(mm, ea, NULL);
  35         if (!vma)
  36                 return -EFAULT;
  37
  38         ret = -EFAULT;
  39         is_write = dsisr & DSISR_ISSTORE;
  40         if (is_write) {
  41                 if (!(vma->vm_flags & VM_WRITE))
  42                         goto out_unlock;
  43         } else {
  44                 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
  45                         goto out_unlock;
  46                 /*
  47                  * PROT_NONE is covered by the VMA check above.
  48                  * and hash should get a NOHPTE fault instead of
  49                  * a PROTFAULT in case fixup is needed for things
  50                  * like autonuma.
  51                  */
  52                 if (!radix_enabled())
  53                         WARN_ON_ONCE(dsisr & DSISR_PROTFAULT);
  54         }
  55
  56         ret = 0;
  57         *flt = handle_mm_fault(vma, ea, is_write ? FAULT_FLAG_WRITE : 0, NULL);
  58
  59         /* The fault is fully completed (including releasing mmap lock) */
  60         if (*flt & VM_FAULT_COMPLETED)
  61                 return 0;
  62
  63         if (unlikely(*flt & VM_FAULT_ERROR)) {
  64                 if (*flt & VM_FAULT_OOM) {
  65                         ret = -ENOMEM;
  66                         goto out_unlock;
  67                 } else if (*flt & (VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV)) {
  68                         ret = -EFAULT;
  69                         goto out_unlock;
  70                 }
  71                 BUG();
  72         }
  73
  74 out_unlock:
  75         mmap_read_unlock(mm);
  76         return ret;
  77 }
  78 EXPORT_SYMBOL_GPL(copro_handle_mm_fault);
  79
  80 #ifdef CONFIG_PPC_64S_HASH_MMU
  81 int copro_calculate_slb(struct mm_struct *mm, u64 ea, struct copro_slb *slb)
  82 {
  83         u64 vsid, vsidkey;
  84         int psize, ssize;
  85
  86         switch (get_region_id(ea)) {
  87         case USER_REGION_ID:
  88                 pr_devel("%s: 0x%llx -- USER_REGION_ID\n", __func__, ea);
  89                 if (mm == NULL)
  90                         return 1;
  91                 psize = get_slice_psize(mm, ea);
  92                 ssize = user_segment_size(ea);
  93                 vsid = get_user_vsid(&mm->context, ea, ssize);
  94                 vsidkey = SLB_VSID_USER;
  95                 break;
  96         case VMALLOC_REGION_ID:
  97                 pr_devel("%s: 0x%llx -- VMALLOC_REGION_ID\n", __func__, ea);
  98                 psize = mmu_vmalloc_psize;
  99                 ssize = mmu_kernel_ssize;
 100                 vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
 101                 vsidkey = SLB_VSID_KERNEL;
 102                 break;
 103         case IO_REGION_ID:
 104                 pr_devel("%s: 0x%llx -- IO_REGION_ID\n", __func__, ea);
 105                 psize = mmu_io_psize;
 106                 ssize = mmu_kernel_ssize;
 107                 vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
 108                 vsidkey = SLB_VSID_KERNEL;
 109                 break;
 110         case LINEAR_MAP_REGION_ID:
 111                 pr_devel("%s: 0x%llx -- LINEAR_MAP_REGION_ID\n", __func__, ea);
 112                 psize = mmu_linear_psize;
 113                 ssize = mmu_kernel_ssize;
 114                 vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
 115                 vsidkey = SLB_VSID_KERNEL;
 116                 break;
 117         default:
 118                 pr_debug("%s: invalid region access at %016llx\n", __func__, ea);
 119                 return 1;
 120         }
 121         /* Bad address */
 122         if (!vsid)
 123                 return 1;
 124
 125         vsid = (vsid << slb_vsid_shift(ssize)) | vsidkey;
 126
 127         vsid |= mmu_psize_defs[psize].sllp |
 128                 ((ssize == MMU_SEGSIZE_1T) ? SLB_VSID_B_1T : 0);
 129
 130         slb->esid = (ea & (ssize == MMU_SEGSIZE_1T ? ESID_MASK_1T : ESID_MASK)) | SLB_ESID_V;
 131         slb->vsid = vsid;
 132
 133         return 0;
 134 }
 135 EXPORT_SYMBOL_GPL(copro_calculate_slb);
 136 #endif