arch/powerpc/mm/copro_fault.c

   1 /*
   2  * CoProcessor (SPU/AFU) mm fault handler
   3  *
   4  * (C) Copyright IBM Deutschland Entwicklung GmbH 2007
   5  *
   6  * Author: Arnd Bergmann <arndb@de.ibm.com>
   7  * Author: Jeremy Kerr <jk@ozlabs.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2, or (at your option)
  12  * any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22  */
  23 #include <linux/sched.h>
  24 #include <linux/mm.h>
  25 #include <linux/export.h>
  26 #include <asm/reg.h>
  27 #include <asm/copro.h>
  28 #include <asm/spu.h>
  29 #include <misc/cxl.h>
  30
  31 /*
  32  * This ought to be kept in sync with the powerpc specific do_page_fault
  33  * function. Currently, there are a few corner cases that we haven't had
  34  * to handle fortunately.
  35  */
  36 int copro_handle_mm_fault(struct mm_struct *mm, unsigned long ea,
  37                 unsigned long dsisr, unsigned *flt)
  38 {
  39         struct vm_area_struct *vma;
  40         unsigned long is_write;
  41         int ret;
  42
  43         if (mm == NULL)
  44                 return -EFAULT;
  45
  46         if (mm->pgd == NULL)
  47                 return -EFAULT;
  48
  49         down_read(&mm->mmap_sem);
  50         ret = -EFAULT;
  51         vma = find_vma(mm, ea);
  52         if (!vma)
  53                 goto out_unlock;
  54
  55         if (ea < vma->vm_start) {
  56                 if (!(vma->vm_flags & VM_GROWSDOWN))
  57                         goto out_unlock;
  58                 if (expand_stack(vma, ea))
  59                         goto out_unlock;
  60         }
  61
  62         is_write = dsisr & DSISR_ISSTORE;
  63         if (is_write) {
  64                 if (!(vma->vm_flags & VM_WRITE))
  65                         goto out_unlock;
  66         } else {
  67                 if (dsisr & DSISR_PROTFAULT)
  68                         goto out_unlock;
  69                 if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
  70                         goto out_unlock;
  71         }
  72
  73         ret = 0;
  74         *flt = handle_mm_fault(mm, vma, ea, is_write ? FAULT_FLAG_WRITE : 0);
  75         if (unlikely(*flt & VM_FAULT_ERROR)) {
  76                 if (*flt & VM_FAULT_OOM) {
  77                         ret = -ENOMEM;
  78                         goto out_unlock;
  79                 } else if (*flt & (VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV)) {
  80                         ret = -EFAULT;
  81                         goto out_unlock;
  82                 }
  83                 BUG();
  84         }
  85
  86         if (*flt & VM_FAULT_MAJOR)
  87                 current->maj_flt++;
  88         else
  89                 current->min_flt++;
  90
  91 out_unlock:
  92         up_read(&mm->mmap_sem);
  93         return ret;
  94 }
  95 EXPORT_SYMBOL_GPL(copro_handle_mm_fault);
  96
  97 int copro_calculate_slb(struct mm_struct *mm, u64 ea, struct copro_slb *slb)
  98 {
  99         u64 vsid;
 100         int psize, ssize;
 101
 102         switch (REGION_ID(ea)) {
 103         case USER_REGION_ID:
 104                 pr_devel("%s: 0x%llx -- USER_REGION_ID\n", __func__, ea);
 105                 psize = get_slice_psize(mm, ea);
 106                 ssize = user_segment_size(ea);
 107                 vsid = get_vsid(mm->context.id, ea, ssize);
 108                 break;
 109         case VMALLOC_REGION_ID:
 110                 pr_devel("%s: 0x%llx -- VMALLOC_REGION_ID\n", __func__, ea);
 111                 if (ea < VMALLOC_END)
 112                         psize = mmu_vmalloc_psize;
 113                 else
 114                         psize = mmu_io_psize;
 115                 ssize = mmu_kernel_ssize;
 116                 vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
 117                 break;
 118         case KERNEL_REGION_ID:
 119                 pr_devel("%s: 0x%llx -- KERNEL_REGION_ID\n", __func__, ea);
 120                 psize = mmu_linear_psize;
 121                 ssize = mmu_kernel_ssize;
 122                 vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
 123                 break;
 124         default:
 125                 pr_debug("%s: invalid region access at %016llx\n", __func__, ea);
 126                 return 1;
 127         }
 128
 129         vsid = (vsid << slb_vsid_shift(ssize)) | SLB_VSID_USER;
 130
 131         vsid |= mmu_psize_defs[psize].sllp |
 132                 ((ssize == MMU_SEGSIZE_1T) ? SLB_VSID_B_1T : 0);
 133
 134         slb->esid = (ea & (ssize == MMU_SEGSIZE_1T ? ESID_MASK_1T : ESID_MASK)) | SLB_ESID_V;
 135         slb->vsid = vsid;
 136
 137         return 0;
 138 }
 139 EXPORT_SYMBOL_GPL(copro_calculate_slb);
 140
 141 void copro_flush_all_slbs(struct mm_struct *mm)
 142 {
 143 #ifdef CONFIG_SPU_BASE
 144         spu_flush_all_slbs(mm);
 145 #endif
 146         cxl_slbia(mm);
 147 }
 148 EXPORT_SYMBOL_GPL(copro_flush_all_slbs);