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 */
 21int 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
 74out_unlock:
 75	mmap_read_unlock(mm);
 76	return ret;
 77}
 78EXPORT_SYMBOL_GPL(copro_handle_mm_fault);
 79
 80#ifdef CONFIG_PPC_64S_HASH_MMU
 81int 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}
135EXPORT_SYMBOL_GPL(copro_calculate_slb);
136#endif