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834020366d
linux/arch/arm/mm
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Will Deacon 834020366d ARM: 8898/1: mm: Don't treat faults reported from cache maintenance as writes 
Translation faults arising from cache maintenance instructions are
rather unhelpfully reported with an FSR value where the WnR field is set
to 1, indicating that the faulting access was a write. Since cache
maintenance instructions on 32-bit ARM do not require any particular
permissions, this can cause our private 'cacheflush' system call to fail
spuriously if a translation fault is generated due to page aging when
targetting a read-only VMA.

In this situation, we will return -EFAULT to userspace, although this is
unfortunately suppressed by the popular '__builtin___clear_cache()'
intrinsic provided by GCC, which returns void.

Although it's tempting to write this off as a userspace issue, we can
actually do a little bit better on CPUs that support LPAE, even if the
short-descriptor format is in use. On these CPUs, cache maintenance
faults additionally set the CM field in the FSR, which we can use to
suppress the write permission checks in the page fault handler and
succeed in performing cache maintenance to read-only areas even in the
presence of a translation fault.

Reported-by: Orion Hodson <oth@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2019-08-23 11:39:34 +01:00
..
abort-ev4.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-ev4t.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-ev5t.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-ev5tj.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-ev6.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-ev7.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-lv4t.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-macro.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-nommu.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
alignment.c ARM: alignment: Mark expected switch fall-throughs 2019-08-09 19:45:31 -05:00
cache-aurora-l2.h
cache-b15-rac.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cache-fa.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cache-feroceon-l2.c
cache-l2x0-pmu.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
cache-l2x0.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
cache-nop.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cache-tauros2.c
cache-tauros3.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 171 2019-05-30 11:26:39 -07:00
cache-uniphier.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
cache-v4.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cache-v4wb.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cache-v4wt.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cache-v6.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cache-v7.S ARM updates: 2019-07-08 21:08:34 -07:00
cache-v7m.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
cache-xsc3l2.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
context.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
copypage-fa.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
copypage-feroceon.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
copypage-v4mc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
copypage-v4wb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
copypage-v4wt.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
copypage-v6.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
copypage-xsc3.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
copypage-xscale.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
dma-mapping-nommu.c dma-mapping updates for Linux 5.3 2019-07-12 15:13:55 -07:00
dma-mapping.c dma-mapping: fix page attributes for dma_mmap_* 2019-08-10 19:52:45 +02:00
dma.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dump.c Driver Core and debugfs changes for 5.3-rc1 2019-07-12 12:24:03 -07:00
extable.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fault-armv.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
fault.c ARM: 8898/1: mm: Don't treat faults reported from cache maintenance as writes 2019-08-23 11:39:34 +01:00
fault.h ARM: 8898/1: mm: Don't treat faults reported from cache maintenance as writes 2019-08-23 11:39:34 +01:00
flush.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
fsr-2level.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fsr-3level.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
highmem.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
hugetlbpage.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
idmap.c ARM: 8817/1: mm: skip cleaning of idmap page tables on LPAE capable cores 2019-02-01 21:44:05 +00:00
init.c arm: use swiotlb for bounce buffering on LPAE configs 2019-07-24 17:29:01 +02:00
iomap.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ioremap.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
Kconfig arm: use swiotlb for bounce buffering on LPAE configs 2019-07-24 17:29:01 +02:00
l2c-common.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
l2c-l2x0-resume.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Makefile Merge branches 'fixes', 'misc' and 'spectre' into for-linus 2018-06-05 10:03:27 +01:00
mm.h ARM: 8864/1: Add workaround for I-Cache line size mismatch between CPU cores 2019-06-20 22:29:58 +01:00
mmap.c exec: pass stack rlimit into mm layout functions 2018-04-11 10:28:37 -07:00
mmu.c arm: switch to generic version of pte allocation 2019-07-12 11:05:45 -07:00
nommu.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
pabort-legacy.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pabort-v6.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pabort-v7.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pageattr.c mm/pgtable: drop pgtable_t variable from pte_fn_t functions 2019-07-12 11:05:46 -07:00
pgd.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
physaddr.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pmsa-v7.c ARM: 8754/1: NOMMU: Move PMSAv7 MPU under it's own namespace 2018-05-19 11:53:46 +01:00
pmsa-v8.c ARM: 8831/1: NOMMU: pmsa-v8: remove unneeded semicolon 2019-02-01 21:44:45 +00:00
proc-arm7tdmi.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
proc-arm9tdmi.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
proc-arm720.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
proc-arm740.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
proc-arm920.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
proc-arm922.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
proc-arm925.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
proc-arm926.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
proc-arm940.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
proc-arm946.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
proc-arm1020.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
proc-arm1020e.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
proc-arm1022.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
proc-arm1026.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
proc-fa526.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
proc-feroceon.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
proc-macros.S ARM: fix the cockup in the previous patch 2018-12-07 13:13:42 +00:00
proc-mohawk.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
proc-sa110.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
proc-sa1100.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
proc-syms.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
proc-v6.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
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proc-v7-3level.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
proc-v7-bugs.c ARM: spectre-v2: per-CPU vtables to work around big.Little systems 2018-11-12 10:51:01 +00:00
proc-v7.S ARM updates: 2019-07-08 21:08:34 -07:00
proc-v7m.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
proc-xsc3.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
proc-xscale.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
ptdump_debugfs.c arm: dump: no need to check return value of debugfs_create functions 2019-06-03 15:49:07 +02:00
pv-fixup-asm.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
tcm.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 194 2019-05-30 11:29:22 -07:00
tlb-fa.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
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