diff options
| -rw-r--r-- | drivers/gpu/drm/ttm/ttm_bo_vm.c | 22 | ||||
| -rw-r--r-- | include/linux/mm.h | 2 | ||||
| -rw-r--r-- | include/linux/mm_types.h | 7 | ||||
| -rw-r--r-- | mm/memory.c | 44 |
4 files changed, 63 insertions, 12 deletions
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index eebb4c06c04d..389128b8c4dd 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c @@ -179,7 +179,6 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf, pgoff_t num_prefault) { struct vm_area_struct *vma = vmf->vma; - struct vm_area_struct cvma = *vma; struct ttm_buffer_object *bo = vma->vm_private_data; struct ttm_bo_device *bdev = bo->bdev; unsigned long page_offset; @@ -250,7 +249,7 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf, goto out_io_unlock; } - cvma.vm_page_prot = ttm_io_prot(bo->mem.placement, prot); + prot = ttm_io_prot(bo->mem.placement, prot); if (!bo->mem.bus.is_iomem) { struct ttm_operation_ctx ctx = { .interruptible = false, @@ -266,7 +265,7 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf, } } else { /* Iomem should not be marked encrypted */ - cvma.vm_page_prot = pgprot_decrypted(cvma.vm_page_prot); + prot = pgprot_decrypted(prot); } /* @@ -289,11 +288,20 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf, pfn = page_to_pfn(page); } + /* + * Note that the value of @prot at this point may differ from + * the value of @vma->vm_page_prot in the caching- and + * encryption bits. This is because the exact location of the + * data may not be known at mmap() time and may also change + * at arbitrary times while the data is mmap'ed. + * See vmf_insert_mixed_prot() for a discussion. + */ if (vma->vm_flags & VM_MIXEDMAP) - ret = vmf_insert_mixed(&cvma, address, - __pfn_to_pfn_t(pfn, PFN_DEV)); + ret = vmf_insert_mixed_prot(vma, address, + __pfn_to_pfn_t(pfn, PFN_DEV), + prot); else - ret = vmf_insert_pfn(&cvma, address, pfn); + ret = vmf_insert_pfn_prot(vma, address, pfn, prot); /* Never error on prefaulted PTEs */ if (unlikely((ret & VM_FAULT_ERROR))) { @@ -325,7 +333,7 @@ vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf) if (ret) return ret; - prot = vm_get_page_prot(vma->vm_flags); + prot = vma->vm_page_prot; ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT); if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) return ret; diff --git a/include/linux/mm.h b/include/linux/mm.h index 73a044ed6981..faa3bb5fe633 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2535,6 +2535,8 @@ vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, unsigned long pfn, pgprot_t pgprot); vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr, pfn_t pfn); +vm_fault_t vmf_insert_mixed_prot(struct vm_area_struct *vma, unsigned long addr, + pfn_t pfn, pgprot_t pgprot); vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma, unsigned long addr, pfn_t pfn); int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len); diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index e87bb864bdb2..c28911c3afa8 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -312,7 +312,12 @@ struct vm_area_struct { /* Second cache line starts here. */ struct mm_struct *vm_mm; /* The address space we belong to. */ - pgprot_t vm_page_prot; /* Access permissions of this VMA. */ + + /* + * Access permissions of this VMA. + * See vmf_insert_mixed_prot() for discussion. + */ + pgprot_t vm_page_prot; unsigned long vm_flags; /* Flags, see mm.h. */ /* diff --git a/mm/memory.c b/mm/memory.c index 1c4be871a237..0bccc622e482 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1664,6 +1664,9 @@ out_unlock: * vmf_insert_pfn_prot should only be used if using multiple VMAs is * impractical. * + * See vmf_insert_mixed_prot() for a discussion of the implication of using + * a value of @pgprot different from that of @vma->vm_page_prot. + * * Context: Process context. May allocate using %GFP_KERNEL. * Return: vm_fault_t value. */ @@ -1737,9 +1740,9 @@ static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn) } static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma, - unsigned long addr, pfn_t pfn, bool mkwrite) + unsigned long addr, pfn_t pfn, pgprot_t pgprot, + bool mkwrite) { - pgprot_t pgprot = vma->vm_page_prot; int err; BUG_ON(!vm_mixed_ok(vma, pfn)); @@ -1782,10 +1785,43 @@ static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma, return VM_FAULT_NOPAGE; } +/** + * vmf_insert_mixed_prot - insert single pfn into user vma with specified pgprot + * @vma: user vma to map to + * @addr: target user address of this page + * @pfn: source kernel pfn + * @pgprot: pgprot flags for the inserted page + * + * This is exactly like vmf_insert_mixed(), except that it allows drivers to + * to override pgprot on a per-page basis. + * + * Typically this function should be used by drivers to set caching- and + * encryption bits different than those of @vma->vm_page_prot, because + * the caching- or encryption mode may not be known at mmap() time. + * This is ok as long as @vma->vm_page_prot is not used by the core vm + * to set caching and encryption bits for those vmas (except for COW pages). + * This is ensured by core vm only modifying these page table entries using + * functions that don't touch caching- or encryption bits, using pte_modify() + * if needed. (See for example mprotect()). + * Also when new page-table entries are created, this is only done using the + * fault() callback, and never using the value of vma->vm_page_prot, + * except for page-table entries that point to anonymous pages as the result + * of COW. + * + * Context: Process context. May allocate using %GFP_KERNEL. + * Return: vm_fault_t value. + */ +vm_fault_t vmf_insert_mixed_prot(struct vm_area_struct *vma, unsigned long addr, + pfn_t pfn, pgprot_t pgprot) +{ + return __vm_insert_mixed(vma, addr, pfn, pgprot, false); +} +EXPORT_SYMBOL(vmf_insert_mixed_prot); + vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr, pfn_t pfn) { - return __vm_insert_mixed(vma, addr, pfn, false); + return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, false); } EXPORT_SYMBOL(vmf_insert_mixed); @@ -1797,7 +1833,7 @@ EXPORT_SYMBOL(vmf_insert_mixed); vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma, unsigned long addr, pfn_t pfn) { - return __vm_insert_mixed(vma, addr, pfn, true); + return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, true); } EXPORT_SYMBOL(vmf_insert_mixed_mkwrite); |