commit 263d6287da upstream.
When a VCPU is created, the kvm_vcpu struct is initialized to zero in
kvm_vm_ioctl_create_vcpu(). On VHE systems, the first time
vcpu.arch.mdcr_el2 is loaded on hardware is in vcpu_load(), before it is
set to a sensible value in kvm_arm_setup_debug() later in the run loop. The
result is that KVM executes for a short time with MDCR_EL2 set to zero.
This has several unintended consequences:
* Setting MDCR_EL2.HPMN to 0 is constrained unpredictable according to ARM
DDI 0487G.a, page D13-3820. The behavior specified by the architecture
in this case is for the PE to behave as if MDCR_EL2.HPMN is set to a
value less than or equal to PMCR_EL0.N, which means that an unknown
number of counters are now disabled by MDCR_EL2.HPME, which is zero.
* The host configuration for the other debug features controlled by
MDCR_EL2 is temporarily lost. This has been harmless so far, as Linux
doesn't use the other fields, but that might change in the future.
Let's avoid both issues by initializing the VCPU's mdcr_el2 field in
kvm_vcpu_vcpu_first_run_init(), thus making sure that the MDCR_EL2 register
has a consistent value after each vcpu_load().
Fixes: d5a21bcc29 ("KVM: arm64: Move common VHE/non-VHE trap config in separate functions")
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210407144857.199746-3-alexandru.elisei@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 4d62e81b60 ]
Giancarlo Ferrari reports the following oops while trying to use kexec:
Unable to handle kernel paging request at virtual address 80112f38
pgd = fd7ef03e
[80112f38] *pgd=0001141e(bad)
Internal error: Oops: 80d [#1] PREEMPT SMP ARM
...
This is caused by machine_kexec() trying to set the kernel text to be
read/write, so it can poke values into the relocation code before
copying it - and an interrupt occuring which changes the page tables.
The subsequent writes then hit read-only sections that trigger a
data abort resulting in the above oops.
Fix this by copying the relocation code, and then writing the variables
into the destination, thereby avoiding the need to make the kernel text
read/write.
Reported-by: Giancarlo Ferrari <giancarlo.ferrari89@gmail.com>
Tested-by: Giancarlo Ferrari <giancarlo.ferrari89@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit c4ad98e4b7 upstream.
KVM currently assumes that an instruction abort can never be a write.
This is in general true, except when the abort is triggered by
a S1PTW on instruction fetch that tries to update the S1 page tables
(to set AF, for example).
This can happen if the page tables have been paged out and brought
back in without seeing a direct write to them (they are thus marked
read only), and the fault handling code will make the PT executable(!)
instead of writable. The guest gets stuck forever.
In these conditions, the permission fault must be considered as
a write so that the Stage-1 update can take place. This is essentially
the I-side equivalent of the problem fixed by 60e21a0ef5 ("arm64: KVM:
Take S1 walks into account when determining S2 write faults").
Update kvm_is_write_fault() to return true on IABT+S1PTW, and introduce
kvm_vcpu_trap_is_exec_fault() that only return true when no faulting
on a S1 fault. Additionally, kvm_vcpu_dabt_iss1tw() is renamed to
kvm_vcpu_abt_iss1tw(), as the above makes it plain that it isn't
specific to data abort.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Will Deacon <will@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200915104218.1284701-2-maz@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit fdfe7cbd58 upstream.
The 'flags' field of 'struct mmu_notifier_range' is used to indicate
whether invalidate_range_{start,end}() are permitted to block. In the
case of kvm_mmu_notifier_invalidate_range_start(), this field is not
forwarded on to the architecture-specific implementation of
kvm_unmap_hva_range() and therefore the backend cannot sensibly decide
whether or not to block.
Add an extra 'flags' parameter to kvm_unmap_hva_range() so that
architectures are aware as to whether or not they are permitted to block.
Cc: <stable@vger.kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Message-Id: <20200811102725.7121-2-will@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[will: Backport to 4.19; use 'blockable' instead of non-existent range flags]
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit aa54ea903a upstream.
Fix build error for the case:
defined(CONFIG_SMP) && !defined(CONFIG_CPU_V6)
config: keystone_defconfig
CC arch/arm/kernel/signal.o
In file included from ../include/linux/random.h:14,
from ../arch/arm/kernel/signal.c:8:
../arch/arm/include/asm/percpu.h: In function ‘__my_cpu_offset’:
../arch/arm/include/asm/percpu.h:29:34: error: ‘current_stack_pointer’ undeclared (first use in this function); did you mean ‘user_stack_pointer’?
: "Q" (*(const unsigned long *)current_stack_pointer));
^~~~~~~~~~~~~~~~~~~~~
user_stack_pointer
Fixes: f227e3ec3b ("random32: update the net random state on interrupt and activity")
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 0370964dd3 upstream.
On a VHE system, the EL1 state is left in the CPU most of the time,
and only syncronized back to memory when vcpu_put() is called (most
of the time on preemption).
Which means that when injecting an exception, we'd better have a way
to either:
(1) write directly to the EL1 sysregs
(2) synchronize the state back to memory, and do the changes there
For an AArch64, we already do (1), so we are safe. Unfortunately,
doing the same thing for AArch32 would be pretty invasive. Instead,
we can easily implement (2) by calling the put/load architectural
backends, and keep preemption disabled. We can then reload the
state back into EL1.
Cc: stable@vger.kernel.org
Reported-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 71f8af1110 ]
Tomas Paukrt reports that his SAM9X60 based system (ARM926, ARMv5TJ)
fails to fix up alignment faults, eventually resulting in a kernel
oops.
The problem occurs when using CONFIG_CPU_USE_DOMAINS with commit
e6978e4bf1 ("ARM: save and reset the address limit when entering an
exception"). This is because the address limit is set back to
TASK_SIZE on exception entry, and, although it is restored on exception
exit, the domain register is not.
Hence, this sequence can occur:
interrupt
pt_regs->addr_limit = addr_limit // USER_DS
addr_limit = USER_DS
alignment exception
__probe_kernel_read()
old_fs = get_fs() // USER_DS
set_fs(KERNEL_DS)
addr_limit = KERNEL_DS
dacr.kernel = DOMAIN_MANAGER
interrupt
pt_regs->addr_limit = addr_limit // KERNEL_DS
addr_limit = USER_DS
alignment exception
__probe_kernel_read()
old_fs = get_fs() // USER_DS
set_fs(KERNEL_DS)
addr_limit = KERNEL_DS
dacr.kernel = DOMAIN_MANAGER
...
set_fs(old_fs)
addr_limit = USER_DS
dacr.kernel = DOMAIN_CLIENT
...
addr_limit = pt_regs->addr_limit // KERNEL_DS
interrupt returns
At this point, addr_limit is correctly restored to KERNEL_DS for
__probe_kernel_read() to continue execution, but dacr.kernel is not,
it has been reset by the set_fs(old_fs) to DOMAIN_CLIENT.
This would not have happened prior to the mentioned commit, because
addr_limit would remain KERNEL_DS, so get_fs() would have returned
KERNEL_DS, and so would correctly nest.
This commit fixes the problem by also saving the DACR on exception
entry if either CONFIG_CPU_SW_DOMAIN_PAN or CONFIG_CPU_USE_DOMAINS are
enabled, and resetting the DACR appropriately on exception entry to
match addr_limit and PAN settings.
Fixes: e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
Reported-by: Tomas Paukrt <tomas.paukrt@advantech.cz>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 747ffc2fcf ]
Consolidate the user access assembly code to asm/uaccess-asm.h. This
moves the csdb, check_uaccess, uaccess_mask_range_ptr, uaccess_enable,
uaccess_disable, uaccess_save, uaccess_restore macros, and creates two
new ones for exception entry and exit - uaccess_entry and uaccess_exit.
This makes the uaccess_save and uaccess_restore macros private to
asm/uaccess-asm.h.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c001899a5d ]
Use unified assembler syntax (UAL) in headers. Divided syntax is
considered deprecated. This will also allow to build the kernel
using LLVM's integrated assembler.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 8101b5a153 ]
Stephen reported the following build warning on a ARM multi_v7_defconfig
build with GCC 9.2.1:
kernel/futex.c: In function 'do_futex':
kernel/futex.c:1676:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized]
1676 | return oldval == cmparg;
| ~~~~~~~^~~~~~~~~
kernel/futex.c:1652:6: note: 'oldval' was declared here
1652 | int oldval, ret;
| ^~~~~~
introduced by commit a08971e948 ("futex: arch_futex_atomic_op_inuser()
calling conventions change").
While that change should not make any difference it confuses GCC which
fails to work out that oldval is not referenced when the return value is
not zero.
GCC fails to properly analyze arch_futex_atomic_op_inuser(). It's not the
early return, the issue is with the assembly macros. GCC fails to detect
that those either set 'ret' to 0 and set oldval or set 'ret' to -EFAULT
which makes oldval uninteresting. The store to the callsite supplied oldval
pointer is conditional on ret == 0.
The straight forward way to solve this is to make the store unconditional.
Aside of addressing the build warning this makes sense anyway because it
removes the conditional from the fastpath. In the error case the stored
value is uninteresting and the extra store does not matter at all.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/87pncao2ph.fsf@nanos.tec.linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit b6ae256afd upstream.
On AArch64 you can do a sign-extended load to either a 32-bit or 64-bit
register, and we should only sign extend the register up to the width of
the register as specified in the operation (by using the 32-bit Wn or
64-bit Xn register specifier).
As it turns out, the architecture provides this decoding information in
the SF ("Sixty-Four" -- how cute...) bit.
Let's take advantage of this with the usual 32-bit/64-bit header file
dance and do the right thing on AArch64 hosts.
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20191212195055.5541-1-christoffer.dall@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1cfbb484de upstream.
Confusingly, there are three SPSR layouts that a kernel may need to deal
with:
(1) An AArch64 SPSR_ELx view of an AArch64 pstate
(2) An AArch64 SPSR_ELx view of an AArch32 pstate
(3) An AArch32 SPSR_* view of an AArch32 pstate
When the KVM AArch32 support code deals with SPSR_{EL2,HYP}, it's either
dealing with #2 or #3 consistently. On arm64 the PSR_AA32_* definitions
match the AArch64 SPSR_ELx view, and on arm the PSR_AA32_* definitions
match the AArch32 SPSR_* view.
However, when we inject an exception into an AArch32 guest, we have to
synthesize the AArch32 SPSR_* that the guest will see. Thus, an AArch64
host needs to synthesize layout #3 from layout #2.
This patch adds a new host_spsr_to_spsr32() helper for this, and makes
use of it in the KVM AArch32 support code. For arm64 we need to shuffle
the DIT bit around, and remove the SS bit, while for arm we can use the
value as-is.
I've open-coded the bit manipulation for now to avoid having to rework
the existing PSR_* definitions into PSR64_AA32_* and PSR32_AA32_*
definitions. I hope to perform a more thorough refactoring in future so
that we can handle pstate view manipulation more consistently across the
kernel tree.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200108134324.46500-4-mark.rutland@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3c2483f154 upstream.
When KVM injects an exception into a guest, it generates the CPSR value
from scratch, configuring CPSR.{M,A,I,T,E}, and setting all other
bits to zero.
This isn't correct, as the architecture specifies that some CPSR bits
are (conditionally) cleared or set upon an exception, and others are
unchanged from the original context.
This patch adds logic to match the architectural behaviour. To make this
simple to follow/audit/extend, documentation references are provided,
and bits are configured in order of their layout in SPSR_EL2. This
layout can be seen in the diagram on ARM DDI 0487E.a page C5-426.
Note that this code is used by both arm and arm64, and is intended to
fuction with the SPSR_EL2 and SPSR_HYP layouts.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200108134324.46500-3-mark.rutland@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit ca70ea43f8 ]
MCPM does a soft reset of the CPUs and uses common cpu_resume() routine to
perform low-level platform initialization. This results in a try to install
HYP stubs for the second time for each CPU and results in false HYP/SVC
mode mismatch detection. The HYP stubs are already installed at the
beginning of the kernel initialization on the boot CPU (head.S) or in the
secondary_startup() for other CPUs. To fix this issue MCPM code should use
a cpu_resume() routine without HYP stubs installation.
This change fixes HYP/SVC mode mismatch on Samsung Exynos5422-based Odroid
XU3/XU4/HC1 boards.
Fixes: 3721924c81 ("ARM: 8081/1: MCPM: provide infrastructure to allow for MCPM loopback")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 344eb5539a ]
getuser() and putuser() (and there underscored variants) use two
strb[t]/ldrb[t] instructions when they are asked to get/put 16-bits.
This means that the read/write is not atomic even when performed to a
16-bit-aligned address.
This leads to problems with vhost: vhost uses __getuser() to read the
vring's 16-bit avail.index field, and if it happens to observe a partial
update of the index, wrong descriptors will be used which will lead to a
breakdown of the virtio communication. A similar problem exists for
__putuser() which is used to write to the vring's used.index field.
The reason these functions use strb[t]/ldrb[t] is because strht/ldrht
instructions did not exist until ARMv6T2/ARMv7. So we should be easily
able to fix this on ARMv7. Also, since all ARMv6 processors also don't
actually use the unprivileged instructions anymore for uaccess (since
CONFIG_CPU_USE_DOMAINS is not used) we can easily fix them too.
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1f5b62f09f ]
The VDSO code uses the kernel helper that was originally designed
to abstract the access between 32 and 64bit systems. It worked so
far because this function is declared as 'inline'.
As we're about to revamp that part of the code, the VDSO would
break. Let's fix it by doing what should have been done from
the start, a proper system register access.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a6ecfb11bf ]
When halting a guest, QEMU flushes the virtual ITS caches, which
amounts to writing to the various tables that the guest has allocated.
When doing this, we fail to take the srcu lock, and the kernel
shouts loudly if running a lockdep kernel:
[ 69.680416] =============================
[ 69.680819] WARNING: suspicious RCU usage
[ 69.681526] 5.1.0-rc1-00008-g600025238f51-dirty #18 Not tainted
[ 69.682096] -----------------------------
[ 69.682501] ./include/linux/kvm_host.h:605 suspicious rcu_dereference_check() usage!
[ 69.683225]
[ 69.683225] other info that might help us debug this:
[ 69.683225]
[ 69.683975]
[ 69.683975] rcu_scheduler_active = 2, debug_locks = 1
[ 69.684598] 6 locks held by qemu-system-aar/4097:
[ 69.685059] #0: 0000000034196013 (&kvm->lock){+.+.}, at: vgic_its_set_attr+0x244/0x3a0
[ 69.686087] #1: 00000000f2ed935e (&its->its_lock){+.+.}, at: vgic_its_set_attr+0x250/0x3a0
[ 69.686919] #2: 000000005e71ea54 (&vcpu->mutex){+.+.}, at: lock_all_vcpus+0x64/0xd0
[ 69.687698] #3: 00000000c17e548d (&vcpu->mutex){+.+.}, at: lock_all_vcpus+0x64/0xd0
[ 69.688475] #4: 00000000ba386017 (&vcpu->mutex){+.+.}, at: lock_all_vcpus+0x64/0xd0
[ 69.689978] #5: 00000000c2c3c335 (&vcpu->mutex){+.+.}, at: lock_all_vcpus+0x64/0xd0
[ 69.690729]
[ 69.690729] stack backtrace:
[ 69.691151] CPU: 2 PID: 4097 Comm: qemu-system-aar Not tainted 5.1.0-rc1-00008-g600025238f51-dirty #18
[ 69.691984] Hardware name: rockchip evb_rk3399/evb_rk3399, BIOS 2019.04-rc3-00124-g2feec69fb1 03/15/2019
[ 69.692831] Call trace:
[ 69.694072] lockdep_rcu_suspicious+0xcc/0x110
[ 69.694490] gfn_to_memslot+0x174/0x190
[ 69.694853] kvm_write_guest+0x50/0xb0
[ 69.695209] vgic_its_save_tables_v0+0x248/0x330
[ 69.695639] vgic_its_set_attr+0x298/0x3a0
[ 69.696024] kvm_device_ioctl_attr+0x9c/0xd8
[ 69.696424] kvm_device_ioctl+0x8c/0xf8
[ 69.696788] do_vfs_ioctl+0xc8/0x960
[ 69.697128] ksys_ioctl+0x8c/0xa0
[ 69.697445] __arm64_sys_ioctl+0x28/0x38
[ 69.697817] el0_svc_common+0xd8/0x138
[ 69.698173] el0_svc_handler+0x38/0x78
[ 69.698528] el0_svc+0x8/0xc
The fix is to obviously take the srcu lock, just like we do on the
read side of things since bf308242ab. One wonders why this wasn't
fixed at the same time, but hey...
Fixes: bf308242ab ("KVM: arm/arm64: VGIC/ITS: protect kvm_read_guest() calls with SRCU lock")
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Sasha Levin (Microsoft) <sashal@kernel.org>
[ Upstream commit 5388a5b821 ]
machine_crash_nonpanic_core() does this:
while (1)
cpu_relax();
because the kernel has crashed, and we have no known safe way to deal
with the CPU. So, we place the CPU into an infinite loop which we
expect it to never exit - at least not until the system as a whole is
reset by some method.
In the absence of erratum 754327, this code assembles to:
b .
In other words, an infinite loop. When erratum 754327 is enabled,
this becomes:
1: dmb
b 1b
It has been observed that on some systems (eg, OMAP4) where, if a
crash is triggered, the system tries to kexec into the panic kernel,
but fails after taking the secondary CPU down - placing it into one
of these loops. This causes the system to livelock, and the most
noticable effect is the system stops after issuing:
Loading crashdump kernel...
to the system console.
The tested as working solution I came up with was to add wfe() to
these infinite loops thusly:
while (1) {
cpu_relax();
wfe();
}
which, without 754327 builds to:
1: wfe
b 1b
or with 754327 is enabled:
1: dmb
wfe
b 1b
Adding "wfe" does two things depending on the environment we're running
under:
- where we're running on bare metal, and the processor implements
"wfe", it stops us spinning endlessly in a loop where we're never
going to do any useful work.
- if we're running in a VM, it allows the CPU to be given back to the
hypervisor and rescheduled for other purposes (maybe a different VM)
rather than wasting CPU cycles inside a crashed VM.
However, in light of erratum 794072, Will Deacon wanted to see 10 nops
as well - which is reasonable to cover the case where we have erratum
754327 enabled _and_ we have a processor that doesn't implement the
wfe hint.
So, we now end up with:
1: wfe
b 1b
when erratum 754327 is disabled, or:
1: dmb
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
wfe
b 1b
when erratum 754327 is enabled. We also get the dmb + 10 nop
sequence elsewhere in the kernel, in terminating loops.
This is reasonable - it means we get the workaround for erratum
794072 when erratum 754327 is enabled, but still relinquish the dead
processor - either by placing it in a lower power mode when wfe is
implemented as such or by returning it to the hypervisior, or in the
case where wfe is a no-op, we use the workaround specified in erratum
794072 to avoid the problem.
These as two entirely orthogonal problems - the 10 nops addresses
erratum 794072, and the wfe is an optimisation that makes the system
more efficient when crashed either in terms of power consumption or
by allowing the host/other VMs to make use of the CPU.
I don't see any reason not to use kexec() inside a VM - it has the
potential to provide automated recovery from a failure of the VMs
kernel with the opportunity for saving a crashdump of the failure.
A panic() with a reboot timeout won't do that, and reading the
libvirt documentation, setting on_reboot to "preserve" won't either
(the documentation states "The preserve action for an on_reboot event
is treated as a destroy".) Surely it has to be a good thing to
avoiding having CPUs spinning inside a VM that is doing no useful
work.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 72cd4064fc ]
ARMv8M introduces support for Security extension to M class, among
other things it affects exception handling, especially, encoding of
EXC_RETURN.
The new bits have been added:
Bit [6] Secure or Non-secure stack
Bit [5] Default callee register stacking
Bit [0] Exception Secure
which conflicts with hard-coded value of EXC_RETURN:
In fact, we only care of few bits:
Bit [3] Mode (0 - Handler, 1 - Thread)
Bit [2] Stack pointer selection (0 - Main, 1 - Process)
We can toggle only those bits and left other bits as they were on
exception entry.
It is basically, what patch does - saves EXC_RETURN when we do
transition form Thread to Handler mode (it is first svc), so later
saved value is used instead of EXC_RET_THREADMODE_PROCESSSTACK.
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1b5ba35078 ]
Arm TC2 fails cpu hotplug stress test.
This issue was tracked down to a missing copy of the new affinity
cpumask for the vexpress-spc interrupt into struct
irq_common_data.affinity when the interrupt is migrated in
migrate_one_irq().
Fix it by replacing the arm specific hotplug cpu migration with the
generic irq code.
This is the counterpart implementation to commit 217d453d47 ("arm64:
fix a migrating irq bug when hotplug cpu").
Tested with cpu hotplug stress test on Arm TC2 (multi_v7_defconfig plus
CONFIG_ARM_BIG_LITTLE_CPUFREQ=y and CONFIG_ARM_VEXPRESS_SPC_CPUFREQ=y).
The vexpress-spc interrupt (irq=22) on this board is affine to CPU0.
Its affinity cpumask now changes correctly e.g. from 0 to 1-4 when
CPU0 is hotplugged out.
Suggested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 358b28f09f ]
The current kvm_psci_vcpu_on implementation will directly try to
manipulate the state of the VCPU to reset it. However, since this is
not done on the thread that runs the VCPU, we can end up in a strangely
corrupted state when the source and target VCPUs are running at the same
time.
Fix this by factoring out all reset logic from the PSCI implementation
and forwarding the required information along with a request to the
target VCPU.
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Commit 383fb3ee80 upstream.
In big.Little systems, some CPUs require the Spectre workarounds in
paths such as the context switch, but other CPUs do not. In order
to handle these differences, we need per-CPU vtables.
We are unable to use the kernel's per-CPU variables to support this
as per-CPU is not initialised at times when we need access to the
vtables, so we have to use an array indexed by logical CPU number.
We use an array-of-pointers to avoid having function pointers in
the kernel's read/write .data section.
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David A. Long <dave.long@linaro.org>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Tested-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Commit e209950fdd upstream.
Allow the way we access members of the processor vtable to be changed
at compile time. We will need to move to per-CPU vtables to fix the
Spectre variant 2 issues on big.Little systems.
However, we have a couple of calls that do not need the vtable
treatment, and indeed cause a kernel warning due to the (later) use
of smp_processor_id(), so also introduce the PROC_TABLE macro for
these which always use CPU 0's function pointers.
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David A. Long <dave.long@linaro.org>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Tested-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Commit 621afc6774 upstream.
A mispredicted conditional call to set_fs could result in the wrong
addr_limit being forwarded under speculation to a subsequent access_ok
check, potentially forming part of a spectre-v1 attack using uaccess
routines.
This patch prevents this forwarding from taking place, but putting heavy
barriers in set_fs after writing the addr_limit.
Porting commit c2f0ad4fc0 ("arm64: uaccess: Prevent speculative use
of the current addr_limit").
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David A. Long <dave.long@linaro.org>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Commit 3aa2df6ec2 upstream.
Use __copy_to_user() rather than __put_user_error() for individual
members when saving VFP state.
This has the benefit of disabling/enabling PAN once per copied struct
intead of once per write.
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David A. Long <dave.long@linaro.org>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a8874e7e8a ]
Change the currently empty defines for __PAGETABLE_PMD_FOLDED,
__PAGETABLE_PUD_FOLDED and __PAGETABLE_P4D_FOLDED to return 1.
This makes it possible to use __is_defined() to test if the
preprocessor define exists.
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
kvm_unmap_hva is long gone, and we only have kvm_unmap_hva_range to
deal with. Drop the now obsolete code.
Fixes: fb1522e099 ("KVM: update to new mmu_notifier semantic v2")
Cc: James Hogan <jhogan@kernel.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Pull ARM 32-bit SoC platform updates from Olof Johansson:
"Most of the SoC updates in this cycle are cleanups and moves to more
modern infrastructure:
- Davinci was moved to common clock framework
- OMAP1-based Amstrad E3 "Superphone" saw a bunch of cleanups to the
keyboard interface (bitbanged AT keyboard via GPIO).
- Removal of some stale code for Renesas platforms
- Power management improvements for i.MX6LL"
* tag 'armsoc-soc' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (112 commits)
ARM: uniphier: select RESET_CONTROLLER
arm64: uniphier: select RESET_CONTROLLER
ARM: uniphier: remove empty Makefile
ARM: exynos: Clear global variable on init error path
ARM: exynos: Remove outdated maintainer information
ARM: shmobile: Always enable ARCH_TIMER on SoCs with A7 and/or A15
ARM: shmobile: r8a7779: hide unused r8a7779_platform_cpu_kill
soc: r9a06g032: don't build SMP files for non-SMP config
ARM: shmobile: Add the R9A06G032 SMP enabler driver
ARM: at91: pm: configure wakeup sources for ULP1 mode
ARM: at91: pm: add PMC fast startup registers defines
ARM: at91: pm: Add ULP1 mode support
ARM: at91: pm: Use ULP0 naming instead of slow clock
ARM: hisi: handle of_iomap and fix missing of_node_put
ARM: hisi: check of_iomap and fix missing of_node_put
ARM: hisi: fix error handling and missing of_node_put
ARM: mx5: Set the DBGEN bit in ARM_GPC register
ARM: imx51: Configure M4IF to avoid visual artifacts
ARM: imx: call imx6sx_cpuidle_init() conditionally for 6sll
ARM: imx: fix i.MX6SLL build
...
KVM/arm updates for 4.19
- Support for Group0 interrupts in guests
- Cache management optimizations for ARMv8.4 systems
- Userspace interface for RAS, allowing error retrival and injection
- Fault path optimization
- Emulated physical timer fixes
- Random cleanups
Pull modules updates from Jessica Yu:
"Summary of modules changes for the 4.19 merge window:
- Fix modules kallsyms for livepatch. Livepatch modules can have
SHN_UNDEF symbols in their module symbol tables for later symbol
resolution, but kallsyms shouldn't be returning these symbols
- Some code cleanups and minor reshuffling in load_module() were done
to log the module name when module signature verification fails"
* tag 'modules-for-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
kernel/module: Use kmemdup to replace kmalloc+memcpy
ARM: module: fix modsign build error
modsign: log module name in the event of an error
module: replace VMLINUX_SYMBOL_STR() with __stringify() or string literal
module: print sensible error code
module: setup load info before module_sig_check()
module: make it clear when we're handling the module copy in info->hdr
module: exclude SHN_UNDEF symbols from kallsyms api
Pull arm64 updates from Will Deacon:
"A bunch of good stuff in here. Worth noting is that we've pulled in
the x86/mm branch from -tip so that we can make use of the core
ioremap changes which allow us to put down huge mappings in the
vmalloc area without screwing up the TLB. Much of the positive
diffstat is because of the rseq selftest for arm64.
Summary:
- Wire up support for qspinlock, replacing our trusty ticket lock
code
- Add an IPI to flush_icache_range() to ensure that stale
instructions fetched into the pipeline are discarded along with the
I-cache lines
- Support for the GCC "stackleak" plugin
- Support for restartable sequences, plus an arm64 port for the
selftest
- Kexec/kdump support on systems booting with ACPI
- Rewrite of our syscall entry code in C, which allows us to zero the
GPRs on entry from userspace
- Support for chained PMU counters, allowing 64-bit event counters to
be constructed on current CPUs
- Ensure scheduler topology information is kept up-to-date with CPU
hotplug events
- Re-enable support for huge vmalloc/IO mappings now that the core
code has the correct hooks to use break-before-make sequences
- Miscellaneous, non-critical fixes and cleanups"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (90 commits)
arm64: alternative: Use true and false for boolean values
arm64: kexec: Add comment to explain use of __flush_icache_range()
arm64: sdei: Mark sdei stack helper functions as static
arm64, kaslr: export offset in VMCOREINFO ELF notes
arm64: perf: Add cap_user_time aarch64
efi/libstub: Only disable stackleak plugin for arm64
arm64: drop unused kernel_neon_begin_partial() macro
arm64: kexec: machine_kexec should call __flush_icache_range
arm64: svc: Ensure hardirq tracing is updated before return
arm64: mm: Export __sync_icache_dcache() for xen-privcmd
drivers/perf: arm-ccn: Use devm_ioremap_resource() to map memory
arm64: Add support for STACKLEAK gcc plugin
arm64: Add stack information to on_accessible_stack
drivers/perf: hisi: update the sccl_id/ccl_id when MT is supported
arm64: fix ACPI dependencies
rseq/selftests: Add support for arm64
arm64: acpi: fix alignment fault in accessing ACPI
efi/arm: map UEFI memory map even w/o runtime services enabled
efi/arm: preserve early mapping of UEFI memory map longer for BGRT
drivers: acpi: add dependency of EFI for arm64
...
Pull ARM updates from Russell King:
- further Spectre variant 1 fixes for user accessors.
- kbuild cleanups (Masahiro Yamada)
- hook up sync core functionality (Will Deacon)
- nommu updates for hypervisor mode booting (Vladimir Murzin)
- use compiler built-ins for fls and ffs (Nicolas Pitre)
* 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: spectre-v1: mitigate user accesses
ARM: spectre-v1: use get_user() for __get_user()
ARM: use __inttype() in get_user()
ARM: oabi-compat: copy semops using __copy_from_user()
ARM: vfp: use __copy_from_user() when restoring VFP state
ARM: 8785/1: use compiler built-ins for ffs and fls
ARM: 8784/1: NOMMU: Allow enter in Hyp mode
ARM: 8783/1: NOMMU: Extend check for VBAR support
ARM: 8782/1: vfp: clean up arch/arm/vfp/Makefile
ARM: signal: copy registers using __copy_from_user()
ARM: tcm: ensure inline stub functions are marked static
ARM: 8779/1: add endianness option to LDFLAGS instead of LD
ARM: 8777/1: Hook up SYNC_CORE functionality for sys_membarrier()
Pull x86 timer updates from Thomas Gleixner:
"Early TSC based time stamping to allow better boot time analysis.
This comes with a general cleanup of the TSC calibration code which
grew warts and duct taping over the years and removes 250 lines of
code. Initiated and mostly implemented by Pavel with help from various
folks"
* 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits)
x86/kvmclock: Mark kvm_get_preset_lpj() as __init
x86/tsc: Consolidate init code
sched/clock: Disable interrupts when calling generic_sched_clock_init()
timekeeping: Prevent false warning when persistent clock is not available
sched/clock: Close a hole in sched_clock_init()
x86/tsc: Make use of tsc_calibrate_cpu_early()
x86/tsc: Split native_calibrate_cpu() into early and late parts
sched/clock: Use static key for sched_clock_running
sched/clock: Enable sched clock early
sched/clock: Move sched clock initialization and merge with generic clock
x86/tsc: Use TSC as sched clock early
x86/tsc: Initialize cyc2ns when tsc frequency is determined
x86/tsc: Calibrate tsc only once
ARM/time: Remove read_boot_clock64()
s390/time: Remove read_boot_clock64()
timekeeping: Default boot time offset to local_clock()
timekeeping: Replace read_boot_clock64() with read_persistent_wall_and_boot_offset()
s390/time: Add read_persistent_wall_and_boot_offset()
x86/xen/time: Output xen sched_clock time from 0
x86/xen/time: Initialize pv xen time in init_hypervisor_platform()
...
Pull x86 mm updates from Thomas Gleixner:
- Make lazy TLB mode even lazier to avoid pointless switch_mm()
operations, which reduces CPU load by 1-2% for memcache workloads
- Small cleanups and improvements all over the place
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Remove redundant check for kmem_cache_create()
arm/asm/tlb.h: Fix build error implicit func declaration
x86/mm/tlb: Make clear_asid_other() static
x86/mm/tlb: Skip atomic operations for 'init_mm' in switch_mm_irqs_off()
x86/mm/tlb: Always use lazy TLB mode
x86/mm/tlb: Only send page table free TLB flush to lazy TLB CPUs
x86/mm/tlb: Make lazy TLB mode lazier
x86/mm/tlb: Restructure switch_mm_irqs_off()
x86/mm/tlb: Leave lazy TLB mode at page table free time
mm: Allocate the mm_cpumask (mm->cpu_bitmap[]) dynamically based on nr_cpu_ids
x86/mm: Add TLB purge to free pmd/pte page interfaces
ioremap: Update pgtable free interfaces with addr
x86/mm: Disable ioremap free page handling on x86-PAE
Pull perf update from Thomas Gleixner:
"The perf crowd presents:
Kernel updates:
- Removal of jprobes
- Cleanup and consolidatation the handling of kprobes
- Cleanup and consolidation of hardware breakpoints
- The usual pile of fixes and updates to PMUs and event descriptors
Tooling updates:
- Updates and improvements all over the place. Nothing outstanding,
just the (good) boring incremental grump work"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (103 commits)
perf trace: Do not require --no-syscalls to suppress strace like output
perf bpf: Include uapi/linux/bpf.h from the 'perf trace' script's bpf.h
perf tools: Allow overriding MAX_NR_CPUS at compile time
perf bpf: Show better message when failing to load an object
perf list: Unify metric group description format with PMU event description
perf vendor events arm64: Update ThunderX2 implementation defined pmu core events
perf cs-etm: Generate branch sample for CS_ETM_TRACE_ON packet
perf cs-etm: Generate branch sample when receiving a CS_ETM_TRACE_ON packet
perf cs-etm: Support dummy address value for CS_ETM_TRACE_ON packet
perf cs-etm: Fix start tracing packet handling
perf build: Fix installation directory for eBPF
perf c2c report: Fix crash for empty browser
perf tests: Fix indexing when invoking subtests
perf trace: Beautify the AF_INET & AF_INET6 'socket' syscall 'protocol' args
perf trace beauty: Add beautifiers for 'socket''s 'protocol' arg
perf trace beauty: Do not print NULL strarray entries
perf beauty: Add a generator for IPPROTO_ socket's protocol constants
tools include uapi: Grab a copy of linux/in.h
perf tests: Fix complex event name parsing
perf evlist: Fix error out while applying initial delay and LBR
...
Pull locking/atomics update from Thomas Gleixner:
"The locking, atomics and memory model brains delivered:
- A larger update to the atomics code which reworks the ordering
barriers, consolidates the atomic primitives, provides the new
atomic64_fetch_add_unless() primitive and cleans up the include
hell.
- Simplify cmpxchg() instrumentation and add instrumentation for
xchg() and cmpxchg_double().
- Updates to the memory model and documentation"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (48 commits)
locking/atomics: Rework ordering barriers
locking/atomics: Instrument cmpxchg_double*()
locking/atomics: Instrument xchg()
locking/atomics: Simplify cmpxchg() instrumentation
locking/atomics/x86: Reduce arch_cmpxchg64*() instrumentation
tools/memory-model: Rename litmus tests to comply to norm7
tools/memory-model/Documentation: Fix typo, smb->smp
sched/Documentation: Update wake_up() & co. memory-barrier guarantees
locking/spinlock, sched/core: Clarify requirements for smp_mb__after_spinlock()
sched/core: Use smp_mb() in wake_woken_function()
tools/memory-model: Add informal LKMM documentation to MAINTAINERS
locking/atomics/Documentation: Describe atomic_set() as a write operation
tools/memory-model: Make scripts executable
tools/memory-model: Remove ACCESS_ONCE() from model
tools/memory-model: Remove ACCESS_ONCE() from recipes
locking/memory-barriers.txt/kokr: Update Korean translation to fix broken DMA vs. MMIO ordering example
MAINTAINERS: Add Daniel Lustig as an LKMM reviewer
tools/memory-model: Fix ISA2+pooncelock+pooncelock+pombonce name
tools/memory-model: Add litmus test for full multicopy atomicity
locking/refcount: Always allow checked forms
...
Pull genirq updates from Thomas Gleixner:
"The irq departement provides:
- A synchronization fix for free_irq() to synchronize just the
removed interrupt thread on shared interrupt lines.
- Consolidate the multi low level interrupt entry handling and mvoe
it to the generic code instead of adding yet another copy for
RISC-V
- Refactoring of the ARM LPI allocator and LPI exposure to the
hypervisor
- Yet another interrupt chip driver for the JZ4725B SoC
- Speed up for /proc/interrupts as people seem to love reading this
file with high frequency
- Miscellaneous fixes and updates"
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
irqchip/gic-v3-its: Make its_lock a raw_spin_lock_t
genirq/irqchip: Remove MULTI_IRQ_HANDLER as it's now obselete
openrisc: Use the new GENERIC_IRQ_MULTI_HANDLER
arm64: Use the new GENERIC_IRQ_MULTI_HANDLER
ARM: Convert to GENERIC_IRQ_MULTI_HANDLER
irqchip: Port the ARM IRQ drivers to GENERIC_IRQ_MULTI_HANDLER
irqchip/gic-v3-its: Reduce minimum LPI allocation to 1 for PCI devices
dt-bindings: irqchip: renesas-irqc: Document r8a77980 support
dt-bindings: irqchip: renesas-irqc: Document r8a77470 support
irqchip/ingenic: Add support for the JZ4725B SoC
irqchip/stm32: Add exti0 translation for stm32mp1
genirq: Remove redundant NULL pointer check in __free_irq()
irqchip/gic-v3-its: Honor hypervisor enforced LPI range
irqchip/gic-v3: Expose GICD_TYPER in the rdist structure
irqchip/gic-v3-its: Drop chunk allocation compatibility
irqchip/gic-v3-its: Move minimum LPI requirements to individual busses
irqchip/gic-v3-its: Use full range of LPIs
irqchip/gic-v3-its: Refactor LPI allocator
genirq: Synchronize only with single thread on free_irq()
genirq: Update code comments wrt recycled thread_mask
...
Return statements in functions returning bool should use true or false
instead of an integer value.
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Spectre variant 1 attacks are about this sequence of pseudo-code:
index = load(user-manipulated pointer);
access(base + index * stride);
In order for the cache side-channel to work, the access() must me made
to memory which userspace can detect whether cache lines have been
loaded. On 32-bit ARM, this must be either user accessible memory, or
a kernel mapping of that same user accessible memory.
The problem occurs when the load() speculatively loads privileged data,
and the subsequent access() is made to user accessible memory.
Any load() which makes use of a user-maniplated pointer is a potential
problem if the data it has loaded is used in a subsequent access. This
also applies for the access() if the data loaded by that access is used
by a subsequent access.
Harden the get_user() accessors against Spectre attacks by forcing out
of bounds addresses to a NULL pointer. This prevents get_user() being
used as the load() step above. As a side effect, put_user() will also
be affected even though it isn't implicated.
Also harden copy_from_user() by redoing the bounds check within the
arm_copy_from_user() code, and NULLing the pointer if out of bounds.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Fixing __get_user() for spectre variant 1 is not sane: we would have to
add address space bounds checking in order to validate that the location
should be accessed, and then zero the address if found to be invalid.
Since __get_user() is supposed to avoid the bounds check, and this is
exactly what get_user() does, there's no point having two different
implementations that are doing the same thing. So, when the Spectre
workarounds are required, make __get_user() an alias of get_user().
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Borrow the x86 implementation of __inttype() to use in get_user() to
select an integer type suitable to temporarily hold the result value.
This is necessary to avoid propagating the volatile nature of the
result argument, which can cause the following warning:
lib/iov_iter.c:413:5: warning: optimization may eliminate reads and/or writes to register variables [-Wvolatile-register-var]
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
