Commit b45f1b3b authored by Dave Airlie's avatar Dave Airlie
Browse files

Merge branch 'ttm-prot-fix' of git://people.freedesktop.org/~thomash/linux into drm-next 



A small fix for the long-standing ttm vm page protection hack.

Sent as a separate PR as it touches mm, has all acks in place.

Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
From: Thomas Hellström (VMware) <thellstrom@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200116102411.3056-1-thomas_os@shipmail.org
parents d47c7f06 5379e4dd

drivers/gpu/drm/ttm/ttm_bo_vm.c

+15 −7
Original line number Diff line number Diff line
@@ -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;

include/linux/mm.h

+2 −0
Original line number Diff line number Diff line
@@ -2533,6 +2533,8 @@ 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);

include/linux/mm_types.h

+6 −1
Original line number Diff line number Diff line
@@ -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. */



	/*

mm/memory.c

+40 −4
Original line number Diff line number Diff line
@@ -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);

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