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From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: DRI Development <dri-devel@lists.freedesktop.org>,
	LKML <linux-kernel@vger.kernel.org>
Cc: kvm@vger.kernel.org, linux-mm@kvack.org,
	linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org, linux-media@vger.kernel.org,
	linux-s390@vger.kernel.org,
	"Daniel Vetter" <daniel.vetter@ffwll.ch>,
	"Daniel Vetter" <daniel.vetter@intel.com>,
	"Jason Gunthorpe" <jgg@ziepe.ca>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Kees Cook" <keescook@chromium.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"John Hubbard" <jhubbard@nvidia.com>,
	"Jérôme Glisse" <jglisse@redhat.com>, "Jan Kara" <jack@suse.cz>,
	"Niklas Schnelle" <schnelle@linux.ibm.com>,
	"Gerald Schaefer" <gerald.schaefer@linux.ibm.com>
Subject: [PATCH 08/13] s390/pci: Remove races against pte updates
Date: Wed,  7 Oct 2020 18:44:21 +0200	[thread overview]
Message-ID: <20201007164426.1812530-9-daniel.vetter@ffwll.ch> (raw)
In-Reply-To: <20201007164426.1812530-1-daniel.vetter@ffwll.ch>

Way back it was a reasonable assumptions that iomem mappings never
change the pfn range they point at. But this has changed:

- gpu drivers dynamically manage their memory nowadays, invalidating
ptes with unmap_mapping_range when buffers get moved

- contiguous dma allocations have moved from dedicated carvetouts to
cma regions. This means if we miss the unmap the pfn might contain
pagecache or anon memory (well anything allocated with GFP_MOVEABLE)

- even /dev/mem now invalidates mappings when the kernel requests that
iomem region when CONFIG_IO_STRICT_DEVMEM is set, see 3234ac664a87
("/dev/mem: Revoke mappings when a driver claims the region")

Accessing pfns obtained from ptes without holding all the locks is
therefore no longer a good idea. Fix this.

Since zpci_memcpy_from|toio seems to not do anything nefarious with
locks we just need to open code get_pfn and follow_pfn and make sure
we drop the locks only after we've done. The write function also needs
the copy_from_user move, since we can't take userspace faults while
holding the mmap sem.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-media@vger.kernel.org
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: linux-s390@vger.kernel.org
---
 arch/s390/pci/pci_mmio.c | 98 +++++++++++++++++++++++-----------------
 1 file changed, 57 insertions(+), 41 deletions(-)

diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c
index 401cf670a243..4d194cb09372 100644
--- a/arch/s390/pci/pci_mmio.c
+++ b/arch/s390/pci/pci_mmio.c
@@ -119,33 +119,15 @@ static inline int __memcpy_toio_inuser(void __iomem *dst,
 	return rc;
 }
 
-static long get_pfn(unsigned long user_addr, unsigned long access,
-		    unsigned long *pfn)
-{
-	struct vm_area_struct *vma;
-	long ret;
-
-	mmap_read_lock(current->mm);
-	ret = -EINVAL;
-	vma = find_vma(current->mm, user_addr);
-	if (!vma)
-		goto out;
-	ret = -EACCES;
-	if (!(vma->vm_flags & access))
-		goto out;
-	ret = follow_pfn(vma, user_addr, pfn);
-out:
-	mmap_read_unlock(current->mm);
-	return ret;
-}
-
 SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
 		const void __user *, user_buffer, size_t, length)
 {
 	u8 local_buf[64];
 	void __iomem *io_addr;
 	void *buf;
-	unsigned long pfn;
+	struct vm_area_struct *vma;
+	pte_t *ptep;
+	spinlock_t *ptl;
 	long ret;
 
 	if (!zpci_is_enabled())
@@ -158,7 +140,7 @@ SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
 	 * We only support write access to MIO capable devices if we are on
 	 * a MIO enabled system. Otherwise we would have to check for every
 	 * address if it is a special ZPCI_ADDR and would have to do
-	 * a get_pfn() which we don't need for MIO capable devices.  Currently
+	 * a pfn lookup which we don't need for MIO capable devices.  Currently
 	 * ISM devices are the only devices without MIO support and there is no
 	 * known need for accessing these from userspace.
 	 */
@@ -176,21 +158,37 @@ SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
 	} else
 		buf = local_buf;
 
-	ret = get_pfn(mmio_addr, VM_WRITE, &pfn);
+	ret = -EFAULT;
+	if (copy_from_user(buf, user_buffer, length))
+		goto out_free;
+
+	mmap_read_lock(current->mm);
+	ret = -EINVAL;
+	vma = find_vma(current->mm, mmio_addr);
+	if (!vma)
+		goto out_unlock_mmap;
+	ret = -EACCES;
+	if (!(vma->vm_flags & VM_WRITE))
+		goto out_unlock_mmap;
+	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+		goto out_unlock_mmap;
+
+	ret = follow_pte_pmd(vma->vm_mm, mmio_addr, NULL, &ptep, NULL, &ptl);
 	if (ret)
-		goto out;
-	io_addr = (void __iomem *)((pfn << PAGE_SHIFT) |
+		goto out_unlock_mmap;
+
+	io_addr = (void __iomem *)((pte_pfn(*ptep) << PAGE_SHIFT) |
 			(mmio_addr & ~PAGE_MASK));
 
-	ret = -EFAULT;
 	if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE)
-		goto out;
-
-	if (copy_from_user(buf, user_buffer, length))
-		goto out;
+		goto out_unlock_pt;
 
 	ret = zpci_memcpy_toio(io_addr, buf, length);
-out:
+out_unlock_pt:
+	pte_unmap_unlock(ptep, ptl);
+out_unlock_mmap:
+	mmap_read_unlock(current->mm);
+out_free:
 	if (buf != local_buf)
 		kfree(buf);
 	return ret;
@@ -274,7 +272,9 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
 	u8 local_buf[64];
 	void __iomem *io_addr;
 	void *buf;
-	unsigned long pfn;
+	struct vm_area_struct *vma;
+	pte_t *ptep;
+	spinlock_t *ptl;
 	long ret;
 
 	if (!zpci_is_enabled())
@@ -287,7 +287,7 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
 	 * We only support read access to MIO capable devices if we are on
 	 * a MIO enabled system. Otherwise we would have to check for every
 	 * address if it is a special ZPCI_ADDR and would have to do
-	 * a get_pfn() which we don't need for MIO capable devices.  Currently
+	 * a pfn lookup which we don't need for MIO capable devices.  Currently
 	 * ISM devices are the only devices without MIO support and there is no
 	 * known need for accessing these from userspace.
 	 */
@@ -306,22 +306,38 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
 		buf = local_buf;
 	}
 
-	ret = get_pfn(mmio_addr, VM_READ, &pfn);
+	mmap_read_lock(current->mm);
+	ret = -EINVAL;
+	vma = find_vma(current->mm, mmio_addr);
+	if (!vma)
+		goto out_unlock_mmap;
+	ret = -EACCES;
+	if (!(vma->vm_flags & VM_WRITE))
+		goto out_unlock_mmap;
+	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+		goto out_unlock_mmap;
+
+	ret = follow_pte_pmd(vma->vm_mm, mmio_addr, NULL, &ptep, NULL, &ptl);
 	if (ret)
-		goto out;
-	io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
+		goto out_unlock_mmap;
+
+	io_addr = (void __iomem *)((pte_pfn(*ptep) << PAGE_SHIFT) |
+			(mmio_addr & ~PAGE_MASK));
 
 	if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) {
 		ret = -EFAULT;
-		goto out;
+		goto out_unlock_pt;
 	}
 	ret = zpci_memcpy_fromio(buf, io_addr, length);
-	if (ret)
-		goto out;
-	if (copy_to_user(user_buffer, buf, length))
+
+out_unlock_pt:
+	pte_unmap_unlock(ptep, ptl);
+out_unlock_mmap:
+	mmap_read_unlock(current->mm);
+
+	if (!ret && copy_to_user(user_buffer, buf, length))
 		ret = -EFAULT;
 
-out:
 	if (buf != local_buf)
 		kfree(buf);
 	return ret;
-- 
2.28.0


WARNING: multiple messages have this Message-ID
From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: DRI Development <dri-devel@lists.freedesktop.org>,
	LKML <linux-kernel@vger.kernel.org>
Cc: linux-s390@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
	"Jan Kara" <jack@suse.cz>, "Kees Cook" <keescook@chromium.org>,
	kvm@vger.kernel.org, "Jason Gunthorpe" <jgg@ziepe.ca>,
	"Daniel Vetter" <daniel.vetter@ffwll.ch>,
	"Niklas Schnelle" <schnelle@linux.ibm.com>,
	linux-mm@kvack.org, "Jérôme Glisse" <jglisse@redhat.com>,
	"John Hubbard" <jhubbard@nvidia.com>,
	"Daniel Vetter" <daniel.vetter@intel.com>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Gerald Schaefer" <gerald.schaefer@linux.ibm.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-media@vger.kernel.org
Subject: [PATCH 08/13] s390/pci: Remove races against pte updates
Date: Wed,  7 Oct 2020 18:44:21 +0200	[thread overview]
Message-ID: <20201007164426.1812530-9-daniel.vetter@ffwll.ch> (raw)
In-Reply-To: <20201007164426.1812530-1-daniel.vetter@ffwll.ch>

Way back it was a reasonable assumptions that iomem mappings never
change the pfn range they point at. But this has changed:

- gpu drivers dynamically manage their memory nowadays, invalidating
ptes with unmap_mapping_range when buffers get moved

- contiguous dma allocations have moved from dedicated carvetouts to
cma regions. This means if we miss the unmap the pfn might contain
pagecache or anon memory (well anything allocated with GFP_MOVEABLE)

- even /dev/mem now invalidates mappings when the kernel requests that
iomem region when CONFIG_IO_STRICT_DEVMEM is set, see 3234ac664a87
("/dev/mem: Revoke mappings when a driver claims the region")

Accessing pfns obtained from ptes without holding all the locks is
therefore no longer a good idea. Fix this.

Since zpci_memcpy_from|toio seems to not do anything nefarious with
locks we just need to open code get_pfn and follow_pfn and make sure
we drop the locks only after we've done. The write function also needs
the copy_from_user move, since we can't take userspace faults while
holding the mmap sem.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-media@vger.kernel.org
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: linux-s390@vger.kernel.org
---
 arch/s390/pci/pci_mmio.c | 98 +++++++++++++++++++++++-----------------
 1 file changed, 57 insertions(+), 41 deletions(-)

diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c
index 401cf670a243..4d194cb09372 100644
--- a/arch/s390/pci/pci_mmio.c
+++ b/arch/s390/pci/pci_mmio.c
@@ -119,33 +119,15 @@ static inline int __memcpy_toio_inuser(void __iomem *dst,
 	return rc;
 }
 
-static long get_pfn(unsigned long user_addr, unsigned long access,
-		    unsigned long *pfn)
-{
-	struct vm_area_struct *vma;
-	long ret;
-
-	mmap_read_lock(current->mm);
-	ret = -EINVAL;
-	vma = find_vma(current->mm, user_addr);
-	if (!vma)
-		goto out;
-	ret = -EACCES;
-	if (!(vma->vm_flags & access))
-		goto out;
-	ret = follow_pfn(vma, user_addr, pfn);
-out:
-	mmap_read_unlock(current->mm);
-	return ret;
-}
-
 SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
 		const void __user *, user_buffer, size_t, length)
 {
 	u8 local_buf[64];
 	void __iomem *io_addr;
 	void *buf;
-	unsigned long pfn;
+	struct vm_area_struct *vma;
+	pte_t *ptep;
+	spinlock_t *ptl;
 	long ret;
 
 	if (!zpci_is_enabled())
@@ -158,7 +140,7 @@ SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
 	 * We only support write access to MIO capable devices if we are on
 	 * a MIO enabled system. Otherwise we would have to check for every
 	 * address if it is a special ZPCI_ADDR and would have to do
-	 * a get_pfn() which we don't need for MIO capable devices.  Currently
+	 * a pfn lookup which we don't need for MIO capable devices.  Currently
 	 * ISM devices are the only devices without MIO support and there is no
 	 * known need for accessing these from userspace.
 	 */
@@ -176,21 +158,37 @@ SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
 	} else
 		buf = local_buf;
 
-	ret = get_pfn(mmio_addr, VM_WRITE, &pfn);
+	ret = -EFAULT;
+	if (copy_from_user(buf, user_buffer, length))
+		goto out_free;
+
+	mmap_read_lock(current->mm);
+	ret = -EINVAL;
+	vma = find_vma(current->mm, mmio_addr);
+	if (!vma)
+		goto out_unlock_mmap;
+	ret = -EACCES;
+	if (!(vma->vm_flags & VM_WRITE))
+		goto out_unlock_mmap;
+	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+		goto out_unlock_mmap;
+
+	ret = follow_pte_pmd(vma->vm_mm, mmio_addr, NULL, &ptep, NULL, &ptl);
 	if (ret)
-		goto out;
-	io_addr = (void __iomem *)((pfn << PAGE_SHIFT) |
+		goto out_unlock_mmap;
+
+	io_addr = (void __iomem *)((pte_pfn(*ptep) << PAGE_SHIFT) |
 			(mmio_addr & ~PAGE_MASK));
 
-	ret = -EFAULT;
 	if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE)
-		goto out;
-
-	if (copy_from_user(buf, user_buffer, length))
-		goto out;
+		goto out_unlock_pt;
 
 	ret = zpci_memcpy_toio(io_addr, buf, length);
-out:
+out_unlock_pt:
+	pte_unmap_unlock(ptep, ptl);
+out_unlock_mmap:
+	mmap_read_unlock(current->mm);
+out_free:
 	if (buf != local_buf)
 		kfree(buf);
 	return ret;
@@ -274,7 +272,9 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
 	u8 local_buf[64];
 	void __iomem *io_addr;
 	void *buf;
-	unsigned long pfn;
+	struct vm_area_struct *vma;
+	pte_t *ptep;
+	spinlock_t *ptl;
 	long ret;
 
 	if (!zpci_is_enabled())
@@ -287,7 +287,7 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
 	 * We only support read access to MIO capable devices if we are on
 	 * a MIO enabled system. Otherwise we would have to check for every
 	 * address if it is a special ZPCI_ADDR and would have to do
-	 * a get_pfn() which we don't need for MIO capable devices.  Currently
+	 * a pfn lookup which we don't need for MIO capable devices.  Currently
 	 * ISM devices are the only devices without MIO support and there is no
 	 * known need for accessing these from userspace.
 	 */
@@ -306,22 +306,38 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
 		buf = local_buf;
 	}
 
-	ret = get_pfn(mmio_addr, VM_READ, &pfn);
+	mmap_read_lock(current->mm);
+	ret = -EINVAL;
+	vma = find_vma(current->mm, mmio_addr);
+	if (!vma)
+		goto out_unlock_mmap;
+	ret = -EACCES;
+	if (!(vma->vm_flags & VM_WRITE))
+		goto out_unlock_mmap;
+	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+		goto out_unlock_mmap;
+
+	ret = follow_pte_pmd(vma->vm_mm, mmio_addr, NULL, &ptep, NULL, &ptl);
 	if (ret)
-		goto out;
-	io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
+		goto out_unlock_mmap;
+
+	io_addr = (void __iomem *)((pte_pfn(*ptep) << PAGE_SHIFT) |
+			(mmio_addr & ~PAGE_MASK));
 
 	if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) {
 		ret = -EFAULT;
-		goto out;
+		goto out_unlock_pt;
 	}
 	ret = zpci_memcpy_fromio(buf, io_addr, length);
-	if (ret)
-		goto out;
-	if (copy_to_user(user_buffer, buf, length))
+
+out_unlock_pt:
+	pte_unmap_unlock(ptep, ptl);
+out_unlock_mmap:
+	mmap_read_unlock(current->mm);
+
+	if (!ret && copy_to_user(user_buffer, buf, length))
 		ret = -EFAULT;
 
-out:
 	if (buf != local_buf)
 		kfree(buf);
 	return ret;
-- 
2.28.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID
From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: DRI Development <dri-devel@lists.freedesktop.org>,
	LKML <linux-kernel@vger.kernel.org>
Cc: linux-s390@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
	"Jan Kara" <jack@suse.cz>, "Kees Cook" <keescook@chromium.org>,
	kvm@vger.kernel.org, "Jason Gunthorpe" <jgg@ziepe.ca>,
	"Daniel Vetter" <daniel.vetter@ffwll.ch>,
	"Niklas Schnelle" <schnelle@linux.ibm.com>,
	linux-mm@kvack.org, "Jérôme Glisse" <jglisse@redhat.com>,
	"John Hubbard" <jhubbard@nvidia.com>,
	"Daniel Vetter" <daniel.vetter@intel.com>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Gerald Schaefer" <gerald.schaefer@linux.ibm.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-media@vger.kernel.org
Subject: [PATCH 08/13] s390/pci: Remove races against pte updates
Date: Wed,  7 Oct 2020 18:44:21 +0200	[thread overview]
Message-ID: <20201007164426.1812530-9-daniel.vetter@ffwll.ch> (raw)
In-Reply-To: <20201007164426.1812530-1-daniel.vetter@ffwll.ch>

Way back it was a reasonable assumptions that iomem mappings never
change the pfn range they point at. But this has changed:

- gpu drivers dynamically manage their memory nowadays, invalidating
ptes with unmap_mapping_range when buffers get moved

- contiguous dma allocations have moved from dedicated carvetouts to
cma regions. This means if we miss the unmap the pfn might contain
pagecache or anon memory (well anything allocated with GFP_MOVEABLE)

- even /dev/mem now invalidates mappings when the kernel requests that
iomem region when CONFIG_IO_STRICT_DEVMEM is set, see 3234ac664a87
("/dev/mem: Revoke mappings when a driver claims the region")

Accessing pfns obtained from ptes without holding all the locks is
therefore no longer a good idea. Fix this.

Since zpci_memcpy_from|toio seems to not do anything nefarious with
locks we just need to open code get_pfn and follow_pfn and make sure
we drop the locks only after we've done. The write function also needs
the copy_from_user move, since we can't take userspace faults while
holding the mmap sem.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-media@vger.kernel.org
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: linux-s390@vger.kernel.org
---
 arch/s390/pci/pci_mmio.c | 98 +++++++++++++++++++++++-----------------
 1 file changed, 57 insertions(+), 41 deletions(-)

diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c
index 401cf670a243..4d194cb09372 100644
--- a/arch/s390/pci/pci_mmio.c
+++ b/arch/s390/pci/pci_mmio.c
@@ -119,33 +119,15 @@ static inline int __memcpy_toio_inuser(void __iomem *dst,
 	return rc;
 }
 
-static long get_pfn(unsigned long user_addr, unsigned long access,
-		    unsigned long *pfn)
-{
-	struct vm_area_struct *vma;
-	long ret;
-
-	mmap_read_lock(current->mm);
-	ret = -EINVAL;
-	vma = find_vma(current->mm, user_addr);
-	if (!vma)
-		goto out;
-	ret = -EACCES;
-	if (!(vma->vm_flags & access))
-		goto out;
-	ret = follow_pfn(vma, user_addr, pfn);
-out:
-	mmap_read_unlock(current->mm);
-	return ret;
-}
-
 SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
 		const void __user *, user_buffer, size_t, length)
 {
 	u8 local_buf[64];
 	void __iomem *io_addr;
 	void *buf;
-	unsigned long pfn;
+	struct vm_area_struct *vma;
+	pte_t *ptep;
+	spinlock_t *ptl;
 	long ret;
 
 	if (!zpci_is_enabled())
@@ -158,7 +140,7 @@ SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
 	 * We only support write access to MIO capable devices if we are on
 	 * a MIO enabled system. Otherwise we would have to check for every
 	 * address if it is a special ZPCI_ADDR and would have to do
-	 * a get_pfn() which we don't need for MIO capable devices.  Currently
+	 * a pfn lookup which we don't need for MIO capable devices.  Currently
 	 * ISM devices are the only devices without MIO support and there is no
 	 * known need for accessing these from userspace.
 	 */
@@ -176,21 +158,37 @@ SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
 	} else
 		buf = local_buf;
 
-	ret = get_pfn(mmio_addr, VM_WRITE, &pfn);
+	ret = -EFAULT;
+	if (copy_from_user(buf, user_buffer, length))
+		goto out_free;
+
+	mmap_read_lock(current->mm);
+	ret = -EINVAL;
+	vma = find_vma(current->mm, mmio_addr);
+	if (!vma)
+		goto out_unlock_mmap;
+	ret = -EACCES;
+	if (!(vma->vm_flags & VM_WRITE))
+		goto out_unlock_mmap;
+	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+		goto out_unlock_mmap;
+
+	ret = follow_pte_pmd(vma->vm_mm, mmio_addr, NULL, &ptep, NULL, &ptl);
 	if (ret)
-		goto out;
-	io_addr = (void __iomem *)((pfn << PAGE_SHIFT) |
+		goto out_unlock_mmap;
+
+	io_addr = (void __iomem *)((pte_pfn(*ptep) << PAGE_SHIFT) |
 			(mmio_addr & ~PAGE_MASK));
 
-	ret = -EFAULT;
 	if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE)
-		goto out;
-
-	if (copy_from_user(buf, user_buffer, length))
-		goto out;
+		goto out_unlock_pt;
 
 	ret = zpci_memcpy_toio(io_addr, buf, length);
-out:
+out_unlock_pt:
+	pte_unmap_unlock(ptep, ptl);
+out_unlock_mmap:
+	mmap_read_unlock(current->mm);
+out_free:
 	if (buf != local_buf)
 		kfree(buf);
 	return ret;
@@ -274,7 +272,9 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
 	u8 local_buf[64];
 	void __iomem *io_addr;
 	void *buf;
-	unsigned long pfn;
+	struct vm_area_struct *vma;
+	pte_t *ptep;
+	spinlock_t *ptl;
 	long ret;
 
 	if (!zpci_is_enabled())
@@ -287,7 +287,7 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
 	 * We only support read access to MIO capable devices if we are on
 	 * a MIO enabled system. Otherwise we would have to check for every
 	 * address if it is a special ZPCI_ADDR and would have to do
-	 * a get_pfn() which we don't need for MIO capable devices.  Currently
+	 * a pfn lookup which we don't need for MIO capable devices.  Currently
 	 * ISM devices are the only devices without MIO support and there is no
 	 * known need for accessing these from userspace.
 	 */
@@ -306,22 +306,38 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
 		buf = local_buf;
 	}
 
-	ret = get_pfn(mmio_addr, VM_READ, &pfn);
+	mmap_read_lock(current->mm);
+	ret = -EINVAL;
+	vma = find_vma(current->mm, mmio_addr);
+	if (!vma)
+		goto out_unlock_mmap;
+	ret = -EACCES;
+	if (!(vma->vm_flags & VM_WRITE))
+		goto out_unlock_mmap;
+	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+		goto out_unlock_mmap;
+
+	ret = follow_pte_pmd(vma->vm_mm, mmio_addr, NULL, &ptep, NULL, &ptl);
 	if (ret)
-		goto out;
-	io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
+		goto out_unlock_mmap;
+
+	io_addr = (void __iomem *)((pte_pfn(*ptep) << PAGE_SHIFT) |
+			(mmio_addr & ~PAGE_MASK));
 
 	if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE) {
 		ret = -EFAULT;
-		goto out;
+		goto out_unlock_pt;
 	}
 	ret = zpci_memcpy_fromio(buf, io_addr, length);
-	if (ret)
-		goto out;
-	if (copy_to_user(user_buffer, buf, length))
+
+out_unlock_pt:
+	pte_unmap_unlock(ptep, ptl);
+out_unlock_mmap:
+	mmap_read_unlock(current->mm);
+
+	if (!ret && copy_to_user(user_buffer, buf, length))
 		ret = -EFAULT;
 
-out:
 	if (buf != local_buf)
 		kfree(buf);
 	return ret;
-- 
2.28.0

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dri-devel@lists.freedesktop.org
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  parent reply	other threads:[~2020-10-07 16:44 UTC|newest]

Thread overview: 166+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-07 16:44 [PATCH 00/13] follow_pfn and other iomap races Daniel Vetter
2020-10-07 16:44 ` Daniel Vetter
2020-10-07 16:44 ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 01/13] drm/exynos: Stop using frame_vector helpers Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 20:32   ` John Hubbard
2020-10-07 20:32     ` John Hubbard
2020-10-07 20:32     ` John Hubbard
2020-10-07 21:32     ` Daniel Vetter
2020-10-07 21:32       ` Daniel Vetter
2020-10-07 21:32       ` Daniel Vetter
2020-10-07 21:36       ` John Hubbard
2020-10-07 21:36         ` John Hubbard
2020-10-07 21:36         ` John Hubbard
2020-10-07 21:50         ` Daniel Vetter
2020-10-07 21:50           ` Daniel Vetter
2020-10-07 21:50           ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 02/13] drm/exynos: Use FOLL_LONGTERM for g2d cmdlists Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 20:43   ` John Hubbard
2020-10-07 20:43     ` John Hubbard
2020-10-07 20:43     ` John Hubbard
2020-10-07 16:44 ` [PATCH 03/13] misc/habana: Stop using frame_vector helpers Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 20:38   ` John Hubbard
2020-10-07 20:38     ` John Hubbard
2020-10-07 20:38     ` John Hubbard
2020-10-07 16:44 ` [PATCH 04/13] misc/habana: Use FOLL_LONGTERM for userptr Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 20:46   ` John Hubbard
2020-10-07 20:46     ` John Hubbard
2020-10-07 20:46     ` John Hubbard
2020-10-07 16:44 ` [PATCH 05/13] mm/frame-vector: Use FOLL_LONGTERM Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:53   ` Jason Gunthorpe
2020-10-07 16:53     ` Jason Gunthorpe
2020-10-07 16:53     ` Jason Gunthorpe
2020-10-07 17:12     ` Daniel Vetter
2020-10-07 17:12       ` Daniel Vetter
2020-10-07 17:12       ` Daniel Vetter
2020-10-07 17:33       ` Jason Gunthorpe
2020-10-07 17:33         ` Jason Gunthorpe
2020-10-07 17:33         ` Jason Gunthorpe
2020-10-07 21:13   ` John Hubbard
2020-10-07 21:13     ` John Hubbard
2020-10-07 21:13     ` John Hubbard
2020-10-07 21:30     ` Daniel Vetter
2020-10-07 21:30       ` Daniel Vetter
2020-10-07 21:30       ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 06/13] media: videobuf2: Move frame_vector into media subsystem Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 22:18   ` John Hubbard
2020-10-07 22:18     ` John Hubbard
2020-10-07 22:18     ` John Hubbard
2020-10-07 16:44 ` [PATCH 07/13] mm: close race in generic_access_phys Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 17:27   ` Jason Gunthorpe
2020-10-07 17:27     ` Jason Gunthorpe
2020-10-07 17:27     ` Jason Gunthorpe
2020-10-07 18:01     ` Daniel Vetter
2020-10-07 18:01       ` Daniel Vetter
2020-10-07 18:01       ` Daniel Vetter
2020-10-07 23:21       ` Jason Gunthorpe
2020-10-07 23:21         ` Jason Gunthorpe
2020-10-07 23:21         ` Jason Gunthorpe
2020-10-08  0:44   ` John Hubbard
2020-10-08  0:44     ` John Hubbard
2020-10-08  0:44     ` John Hubbard
2020-10-08  7:23     ` Daniel Vetter
2020-10-08  7:23       ` Daniel Vetter
2020-10-08  7:23       ` Daniel Vetter
2020-10-07 16:44 ` Daniel Vetter [this message]
2020-10-07 16:44   ` [PATCH 08/13] s390/pci: Remove races against pte updates Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-08 16:44   ` Gerald Schaefer
2020-10-08 16:44     ` Gerald Schaefer
2020-10-08 16:44     ` Gerald Schaefer
2020-10-08 17:16     ` Daniel Vetter
2020-10-08 17:16       ` Daniel Vetter
2020-10-08 17:16       ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 09/13] PCI: obey iomem restrictions for procfs mmap Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 18:46   ` Bjorn Helgaas
2020-10-07 18:46     ` Bjorn Helgaas
2020-10-07 18:46     ` Bjorn Helgaas
2020-10-07 18:46     ` Bjorn Helgaas
2020-10-07 16:44 ` [PATCH 10/13] PCI: revoke mappings like devmem Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 18:41   ` Bjorn Helgaas
2020-10-07 18:41     ` Bjorn Helgaas
2020-10-07 18:41     ` Bjorn Helgaas
2020-10-07 19:24     ` Daniel Vetter
2020-10-07 19:24       ` Daniel Vetter
2020-10-07 19:24       ` Daniel Vetter
2020-10-07 19:33   ` Dan Williams
2020-10-07 19:33     ` Dan Williams
2020-10-07 19:33     ` Dan Williams
2020-10-07 19:47     ` Daniel Vetter
2020-10-07 19:47       ` Daniel Vetter
2020-10-07 19:47       ` Daniel Vetter
2020-10-07 22:23       ` Dan Williams
2020-10-07 22:23         ` Dan Williams
2020-10-07 22:23         ` Dan Williams
2020-10-07 22:29         ` Dan Williams
2020-10-07 22:29           ` Dan Williams
2020-10-07 22:29           ` Dan Williams
2020-10-08  8:09           ` Daniel Vetter
2020-10-08  8:09             ` Daniel Vetter
2020-10-08  8:09             ` Daniel Vetter
2020-10-07 23:24     ` Jason Gunthorpe
2020-10-07 23:24       ` Jason Gunthorpe
2020-10-07 23:24       ` Jason Gunthorpe
2020-10-08  7:31       ` Daniel Vetter
2020-10-08  7:31         ` Daniel Vetter
2020-10-08  7:31         ` Daniel Vetter
2020-10-08  7:49       ` Dan Williams
2020-10-08  7:49         ` Dan Williams
2020-10-08  7:49         ` Dan Williams
2020-10-08  8:13         ` Daniel Vetter
2020-10-08  8:13           ` Daniel Vetter
2020-10-08  8:13           ` Daniel Vetter
2020-10-08  8:35           ` Dan Williams
2020-10-08  8:35             ` Dan Williams
2020-10-08  8:35             ` Dan Williams
2020-10-08 12:41         ` Jason Gunthorpe
2020-10-08 12:41           ` Jason Gunthorpe
2020-10-08 12:41           ` Jason Gunthorpe
2020-10-07 16:44 ` [PATCH 11/13] mm: add unsafe_follow_pfn Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 17:36   ` Jason Gunthorpe
2020-10-07 17:36     ` Jason Gunthorpe
2020-10-07 17:36     ` Jason Gunthorpe
2020-10-07 18:10     ` Daniel Vetter
2020-10-07 18:10       ` Daniel Vetter
2020-10-07 18:10       ` Daniel Vetter
2020-10-07 19:00       ` Jason Gunthorpe
2020-10-07 19:00         ` Jason Gunthorpe
2020-10-07 19:00         ` Jason Gunthorpe
2020-10-07 19:38         ` Daniel Vetter
2020-10-07 19:38           ` Daniel Vetter
2020-10-07 19:38           ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 12/13] media/videbuf1|2: Mark follow_pfn usage as unsafe Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 13/13] vfio/type1: Mark follow_pfn " Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 17:39   ` Jason Gunthorpe
2020-10-07 17:39     ` Jason Gunthorpe
2020-10-07 17:39     ` Jason Gunthorpe
2020-10-07 18:14     ` Daniel Vetter
2020-10-07 18:14       ` Daniel Vetter
2020-10-07 18:14       ` Daniel Vetter
2020-10-07 18:47       ` Jason Gunthorpe
2020-10-07 18:47         ` Jason Gunthorpe
2020-10-07 18:47         ` Jason Gunthorpe

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