Pull arm64 fix from Will Deacon:
"Ensure PAN is re-enabled following user fault in uaccess routines.
After I thought we were done for 5.4, we had a report this week of a
nasty issue that has been shown to leak data between different user
address spaces thanks to corruption of entries in the TLB. In
hindsight, we should have spotted this in review when the PAN code was
merged back in v4.3, but hindsight is 20/20 and I'm trying not to beat
myself up too much about it despite being fairly miserable.
Anyway, the fix is "obvious" but the actual failure is more more
subtle, and is described in the commit message. I've included a fairly
mechanical follow-up patch here as well, which moves this checking out
into the C wrappers which is what we do for {get,put}_user() already
and allows us to remove these bloody assembly macros entirely. The
patches have passed kernelci [1] [2] [3] and CKI [4] tests over night,
as well as some targetted testing [5] for this particular issue.
The first patch is tagged for stable and should be applied to 4.14,
4.19 and 5.3. I have separate backports for 4.4 and 4.9, which I'll
send out once this has landed in your tree (although the original
patch applies cleanly, it won't build for those two trees).
Thanks to Pavel Tatashin for reporting this and Mark Rutland for
helping to diagnose the issue and review/test the solution"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: uaccess: Remove uaccess_*_not_uao asm macros
arm64: uaccess: Ensure PAN is re-enabled after unhandled uaccess fault
It is safer and simpler to drop the uaccess assembly macros in favour of
inline C functions. Although this bloats the Image size slightly, it
aligns our user copy routines with '{get,put}_user()' and generally
makes the code a lot easier to reason about.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
[will: tweaked commit message and changed temporary variable names]
Signed-off-by: Will Deacon <will@kernel.org>
A number of our uaccess routines ('__arch_clear_user()' and
'__arch_copy_{in,from,to}_user()') fail to re-enable PAN if they
encounter an unhandled fault whilst accessing userspace.
For CPUs implementing both hardware PAN and UAO, this bug has no effect
when both extensions are in use by the kernel.
For CPUs implementing hardware PAN but not UAO, this means that a kernel
using hardware PAN may execute portions of code with PAN inadvertently
disabled, opening us up to potential security vulnerabilities that rely
on userspace access from within the kernel which would usually be
prevented by this mechanism. In other words, parts of the kernel run the
same way as they would on a CPU without PAN implemented/emulated at all.
For CPUs not implementing hardware PAN and instead relying on software
emulation via 'CONFIG_ARM64_SW_TTBR0_PAN=y', the impact is unfortunately
much worse. Calling 'schedule()' with software PAN disabled means that
the next task will execute in the kernel using the page-table and ASID
of the previous process even after 'switch_mm()', since the actual
hardware switch is deferred until return to userspace. At this point, or
if there is a intermediate call to 'uaccess_enable()', the page-table
and ASID of the new process are installed. Sadly, due to the changes
introduced by KPTI, this is not an atomic operation and there is a very
small window (two instructions) where the CPU is configured with the
page-table of the old task and the ASID of the new task; a speculative
access in this state is disastrous because it would corrupt the TLB
entries for the new task with mappings from the previous address space.
As Pavel explains:
| I was able to reproduce memory corruption problem on Broadcom's SoC
| ARMv8-A like this:
|
| Enable software perf-events with PERF_SAMPLE_CALLCHAIN so userland's
| stack is accessed and copied.
|
| The test program performed the following on every CPU and forking
| many processes:
|
| unsigned long *map = mmap(NULL, PAGE_SIZE, PROT_READ|PROT_WRITE,
| MAP_SHARED | MAP_ANONYMOUS, -1, 0);
| map[0] = getpid();
| sched_yield();
| if (map[0] != getpid()) {
| fprintf(stderr, "Corruption detected!");
| }
| munmap(map, PAGE_SIZE);
|
| From time to time I was getting map[0] to contain pid for a
| different process.
Ensure that PAN is re-enabled when returning after an unhandled user
fault from our uaccess routines.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Cc: <stable@vger.kernel.org>
Fixes: 338d4f49d6f7 ("arm64: kernel: Add support for Privileged Access Never")
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
[will: rewrote commit message]
Signed-off-by: Will Deacon <will@kernel.org>
Pull ARM SoC fixes from Olof Johansson:
"A set of fixes that have trickled in over the last couple of weeks:
- MAINTAINER update for Cavium/Marvell ThunderX2
- stm32 tweaks to pinmux for Joystick/Camera, and RAM allocation for
CAN interfaces
- i.MX fixes for voltage regulator GPIO mappings, fixes voltage
scaling issues
- More i.MX fixes for various issues on i.MX eval boards: interrupt
storm due to u-boot leaving pins in new states, fixing power button
config, a couple of compatible-string corrections.
- Powerdown and Suspend/Resume fixes for Allwinner A83-based tablets
- A few documentation tweaks and a fix of a memory leak in the reset
subsystem"
* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
MAINTAINERS: update Cavium ThunderX2 maintainers
ARM: dts: stm32: change joystick pinctrl definition on stm32mp157c-ev1
ARM: dts: stm32: remove OV5640 pinctrl definition on stm32mp157c-ev1
ARM: dts: stm32: Fix CAN RAM mapping on stm32mp157c
ARM: dts: stm32: relax qspi pins slew-rate for stm32mp157
arm64: dts: zii-ultra: fix ARM regulator GPIO handle
ARM: sunxi: Fix CPU powerdown on A83T
ARM: dts: sun8i-a83t-tbs-a711: Fix WiFi resume from suspend
arm64: dts: imx8mn: fix compatible string for sdma
arm64: dts: imx8mm: fix compatible string for sdma
reset: fix reset_control_ops kerneldoc comment
ARM: dts: imx6-logicpd: Re-enable SNVS power key
soc: imx: gpc: fix initialiser format
ARM: dts: imx6qdl-sabreauto: Fix storm of accelerometer interrupts
arm64: dts: ls1028a: fix a compatible issue
reset: fix reset_control_get_exclusive kerneldoc comment
reset: fix reset_control_lookup kerneldoc comment
reset: fix of_reset_control_get_count kerneldoc comment
reset: fix of_reset_simple_xlate kerneldoc comment
reset: Fix memory leak in reset_control_array_put()
Pull timer fixes from Thomas Gleixner:
"A small set of fixes for timekeepoing and clocksource drivers:
- VDSO data was updated conditional on the availability of a VDSO
capable clocksource. This causes the VDSO functions which do not
depend on a VDSO capable clocksource to operate on stale data.
Always update unconditionally.
- Prevent a double free in the mediatek driver
- Use the proper helper in the sh_mtu2 driver so it won't attempt to
initialize non-existing interrupts"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timekeeping/vsyscall: Update VDSO data unconditionally
clocksource/drivers/sh_mtu2: Do not loop using platform_get_irq_by_name()
clocksource/drivers/mediatek: Fix error handling
Pull arm64 fix from Will Deacon:
"Fix pte_same() to avoid getting stuck on write fault.
This single arm64 fix is a revert of 747a70e60b72 ("arm64: Fix
copy-on-write referencing in HugeTLB"), not because that patch was
wrong, but because it was broken by aa57157be69f ("arm64: Ensure
VM_WRITE|VM_SHARED ptes are clean by default") which we merged in
-rc6.
We spotted the issue in Android (AOSP), where one of the JIT threads
gets stuck on a write fault during boot because the faulting pte is
marked as PTE_DIRTY | PTE_WRITE | PTE_RDONLY and the fault handler
decides that there's nothing to do thanks to pte_same() masking out
PTE_RDONLY.
Thanks to John Stultz for reporting this and testing this so quickly,
and to Steve Capper for confirming that the HugeTLB tests continue to
pass"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: Do not mask out PTE_RDONLY in pte_same()
Following commit 73e86cb03cf2 ("arm64: Move PTE_RDONLY bit handling out
of set_pte_at()"), the PTE_RDONLY bit is no longer managed by
set_pte_at() but built into the PAGE_* attribute definitions.
Consequently, pte_same() must include this bit when checking two PTEs
for equality.
Remove the arm64-specific pte_same() function, practically reverting
commit 747a70e60b72 ("arm64: Fix copy-on-write referencing in HugeTLB")
Fixes: 73e86cb03cf2 ("arm64: Move PTE_RDONLY bit handling out of set_pte_at()")
Cc: <stable@vger.kernel.org> # 4.14.x-
Cc: Will Deacon <will@kernel.org>
Cc: Steve Capper <steve.capper@arm.com>
Reported-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
The update of the VDSO data is depending on __arch_use_vsyscall() returning
True. This is a leftover from the attempt to map the features of various
architectures 1:1 into generic code.
The usage of __arch_use_vsyscall() in the actual vsyscall implementations
got dropped and replaced by the requirement for the architecture code to
return U64_MAX if the global clocksource is not usable in the VDSO.
But the __arch_use_vsyscall() check in the update code stayed which causes
the VDSO data to be stale or invalid when an architecture actually
implements that function and returns False when the current clocksource is
not usable in the VDSO.
As a consequence the VDSO implementations of clock_getres(), time(),
clock_gettime(CLOCK_.*_COARSE) operate on invalid data and return bogus
information.
Remove the __arch_use_vsyscall() check from the VDSO update function and
update the VDSO data unconditionally.
[ tglx: Massaged changelog and removed the now useless implementations in
asm-generic/ARM64/MIPS ]
Fixes: 44f57d788e7deecb50 ("timekeeping: Provide a generic update_vsyscall() implementation")
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1571887709-11447-1-git-send-email-chenhc@lemote.com
i.MX fixes for 5.4, 3rd round: - Fix the GPIO number that is controlling core voltage on imx8mq-zii-ultra board. * tag 'imx-fixes-5.4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux: arm64: dts: zii-ultra: fix ARM regulator GPIO handle Link: https://lore.kernel.org/r/20191104084513.GW24620@dragon Signed-off-by: Olof Johansson <olof@lixom.net>
The GPIO handle is referencing the wrong GPIO, so the voltage did not actually change as intended. The pinmux is already correct, so just correct the GPIO number. Fixes: 4a13b3bec3b4 (arm64: dts: imx: add Zii Ultra board support) Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Signed-off-by: Shawn Guo <shawnguo@kernel.org>