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Daniel Vetter a67a88b0b8 s390/pci: remove races against pte updates 
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
commit 3234ac664a ("/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're done. The write function also needs
the copy_from_user move, since we can't take userspace faults while
holding the mmap sem.

Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
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: 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: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2020-11-09 11:21:00 +01:00
..
alpha arch-cleanup-2020-10-22 2020-10-23 10:06:38 -07:00
arc ARC: [plat-hsdk] Remap CCMs super early in asm boot trampoline 2020-11-02 11:45:09 -08:00
arm ARM, xtensa: highmem: avoid clobbering non-page aligned memory reservations 2020-11-04 10:42:57 +02:00
arm64 arm64 fixes for -rc3 2020-11-06 12:42:49 -08:00
c6x arch-cleanup-2020-10-22 2020-10-23 10:06:38 -07:00
csky treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
h8300 arch-cleanup-2020-10-22 2020-10-23 10:06:38 -07:00
hexagon arch-cleanup-2020-10-22 2020-10-23 10:06:38 -07:00
ia64 treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
m68k arch-cleanup-2020-10-22 2020-10-23 10:06:38 -07:00
microblaze treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
mips treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
nds32 arch-cleanup-2020-10-22 2020-10-23 10:06:38 -07:00
nios2 arch-cleanup-2020-10-22 2020-10-23 10:06:38 -07:00
openrisc arch-cleanup-2020-10-22 2020-10-23 10:06:38 -07:00
parisc treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
powerpc powerpc/numa: Fix build when CONFIG_NUMA=n 2020-11-06 14:16:19 +11:00
riscv RISC-V: Fix the VDSO symbol generaton for binutils-2.35+ 2020-11-06 00:03:48 -08:00
s390 s390/pci: remove races against pte updates 2020-11-09 11:21:00 +01:00
sh treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
sparc treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
um arch/um: partially revert the conversion to __section() macro 2020-10-26 15:39:37 -07:00
x86 A set of x86 fixes: 2020-11-08 10:09:36 -08:00
xtensa ARM, xtensa: highmem: avoid clobbering non-page aligned memory reservations 2020-11-04 10:42:57 +02:00
.gitignore
Kconfig Merge branch 'work.set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-22 09:59:21 -07:00