cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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iommu-sva-lib.c (1883B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Helpers for IOMMU drivers implementing SVA
      4 */
      5#include <linux/mutex.h>
      6#include <linux/sched/mm.h>
      7
      8#include "iommu-sva-lib.h"
      9
     10static DEFINE_MUTEX(iommu_sva_lock);
     11static DECLARE_IOASID_SET(iommu_sva_pasid);
     12
     13/**
     14 * iommu_sva_alloc_pasid - Allocate a PASID for the mm
     15 * @mm: the mm
     16 * @min: minimum PASID value (inclusive)
     17 * @max: maximum PASID value (inclusive)
     18 *
     19 * Try to allocate a PASID for this mm, or take a reference to the existing one
     20 * provided it fits within the [@min, @max] range. On success the PASID is
     21 * available in mm->pasid and will be available for the lifetime of the mm.
     22 *
     23 * Returns 0 on success and < 0 on error.
     24 */
     25int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max)
     26{
     27	int ret = 0;
     28	ioasid_t pasid;
     29
     30	if (min == INVALID_IOASID || max == INVALID_IOASID ||
     31	    min == 0 || max < min)
     32		return -EINVAL;
     33
     34	mutex_lock(&iommu_sva_lock);
     35	/* Is a PASID already associated with this mm? */
     36	if (pasid_valid(mm->pasid)) {
     37		if (mm->pasid < min || mm->pasid >= max)
     38			ret = -EOVERFLOW;
     39		goto out;
     40	}
     41
     42	pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm);
     43	if (!pasid_valid(pasid))
     44		ret = -ENOMEM;
     45	else
     46		mm_pasid_set(mm, pasid);
     47out:
     48	mutex_unlock(&iommu_sva_lock);
     49	return ret;
     50}
     51EXPORT_SYMBOL_GPL(iommu_sva_alloc_pasid);
     52
     53/* ioasid_find getter() requires a void * argument */
     54static bool __mmget_not_zero(void *mm)
     55{
     56	return mmget_not_zero(mm);
     57}
     58
     59/**
     60 * iommu_sva_find() - Find mm associated to the given PASID
     61 * @pasid: Process Address Space ID assigned to the mm
     62 *
     63 * On success a reference to the mm is taken, and must be released with mmput().
     64 *
     65 * Returns the mm corresponding to this PASID, or an error if not found.
     66 */
     67struct mm_struct *iommu_sva_find(ioasid_t pasid)
     68{
     69	return ioasid_find(&iommu_sva_pasid, pasid, __mmget_not_zero);
     70}
     71EXPORT_SYMBOL_GPL(iommu_sva_find);