linux-stable.git/arch, branch v5.7.9

s390/maccess: add no DAT mode to kernel_write

2020-07-16T06:13:36+00:00

[ Upstream commit d6df52e9996dcc2062c3d9c9123288468bb95b52 ]

To be able to patch kernel code before paging is initialized do plain
memcpy if DAT is off. This is required to enable early jump label
initialization.

Reviewed-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Heiko Carstens 
Signed-off-by: Sasha Levin

s390: Change s390_kernel_write() return type to match memcpy()

2020-07-16T06:13:35+00:00

[ Upstream commit cb2cceaefb4c4dc28fc27ff1f1b2d258bfc10353 ]

s390_kernel_write()'s function type is almost identical to memcpy().
Change its return type to "void *" so they can be used interchangeably.

Cc: linux-s390@vger.kernel.org
Cc: heiko.carstens@de.ibm.com
Signed-off-by: Josh Poimboeuf 
Acked-by: Joe Lawrence 
Acked-by: Miroslav Benes 
Acked-by: Gerald Schaefer  # s390
Signed-off-by: Jiri Kosina 
Signed-off-by: Sasha Levin

arm64: arch_timer: Allow an workaround descriptor to disable compat vdso

2020-07-16T06:13:34+00:00

commit c1fbec4ac0d701f350a581941d35643d5a9cd184 upstream.

As we are about to disable the vdso for compat tasks in some circumstances,
let's allow a workaround descriptor to express exactly that.

Signed-off-by: Marc Zyngier 
Acked-by: Mark Rutland 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200706163802.1836732-3-maz@kernel.org
Signed-off-by: Will Deacon 
Signed-off-by: Greg Kroah-Hartman

arm64: Introduce a way to disable the 32bit vdso

2020-07-16T06:13:34+00:00

commit 97884ca8c2925d14c32188e865069f21378b4b4f upstream.

We have a class of errata (grouped under the ARM64_WORKAROUND_1418040
banner) that force the trapping of counter access from 32bit EL0.

We would normally disable the whole vdso for such defect, except that
it would disable it for 64bit userspace as well, which is a shame.

Instead, add a new vdso_clock_mode, which signals that the vdso
isn't usable for compat tasks.  This gets checked in the new
vdso_clocksource_ok() helper, now provided for the 32bit vdso.

Signed-off-by: Marc Zyngier 
Acked-by: Mark Rutland 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200706163802.1836732-2-maz@kernel.org
Signed-off-by: Will Deacon 
Signed-off-by: Greg Kroah-Hartman

s390/mm: fix huge pte soft dirty copying

2020-07-16T06:13:34+00:00

commit 528a9539348a0234375dfaa1ca5dbbb2f8f8e8d2 upstream.

If the pmd is soft dirty we must mark the pte as soft dirty (and not dirty).
This fixes some cases for guest migration with huge page backings.

Cc:  # 4.8
Fixes: bc29b7ac1d9f ("s390/mm: clean up pte/pmd encoding")
Reviewed-by: Christian Borntraeger 
Reviewed-by: Gerald Schaefer 
Signed-off-by: Janosch Frank 
Signed-off-by: Heiko Carstens 
Signed-off-by: Greg Kroah-Hartman

s390/setup: init jump labels before command line parsing

2020-07-16T06:13:34+00:00

commit 95e61b1b5d6394b53d147c0fcbe2ae70fbe09446 upstream.

Command line parameters might set static keys. This is true for s390 at
least since commit 6471384af2a6 ("mm: security: introduce init_on_alloc=1
and init_on_free=1 boot options"). To avoid the following WARN:

static_key_enable_cpuslocked(): static key 'init_on_alloc+0x0/0x40' used
before call to jump_label_init()

call jump_label_init() just before parse_early_param().
jump_label_init() is safe to call multiple times (x86 does that), doesn't
do any memory allocations and hence should be safe to call that early.

Fixes: 6471384af2a6 ("mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options")
Cc:  # 5.3: d6df52e9996d: s390/maccess: add no DAT mode to kernel_write
Cc:  # 5.3
Reviewed-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Heiko Carstens 
Signed-off-by: Greg Kroah-Hartman

ARC: elf: use right ELF_ARCH

2020-07-16T06:13:33+00:00

commit b7faf971081a4e56147f082234bfff55135305cb upstream.

Cc: 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

ARC: entry: fix potential EFA clobber when TIF_SYSCALL_TRACE

2020-07-16T06:13:33+00:00

commit 00fdec98d9881bf5173af09aebd353ab3b9ac729 upstream.

Trap handler for syscall tracing reads EFA (Exception Fault Address),
in case strace wants PC of trap instruction (EFA is not part of pt_regs
as of current code).

However this EFA read is racy as it happens after dropping to pure
kernel mode (re-enabling interrupts). A taken interrupt could
context-switch, trigger a different task's trap, clobbering EFA for this
execution context.

Fix this by reading EFA early, before re-enabling interrupts. A slight
side benefit is de-duplication of FAKE_RET_FROM_EXCPN in trap handler.
The trap handler is common to both ARCompact and ARCv2 builds too.

This just came out of code rework/review and no real problem was reported
but is clearly a potential problem specially for strace.

Cc: 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

KVM: arm64: Fix kvm_reset_vcpu() return code being incorrect with SVE

2020-07-16T06:13:29+00:00

If SVE is enabled then 'ret' can be assigned the return value of
kvm_vcpu_enable_sve() which may be 0 causing future "goto out" sites to
erroneously return 0 on failure rather than -EINVAL as expected.

Remove the initialisation of 'ret' and make setting the return value
explicit to avoid this situation in the future.

Fixes: 9a3cdf26e336 ("KVM: arm64/sve: Allow userspace to enable SVE for vcpus")
Cc: stable@vger.kernel.org
Reported-by: James Morse 
Signed-off-by: Steven Price 
Signed-off-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20200617105456.28245-1-steven.price@arm.com
Signed-off-by: Sasha Levin

KVM: x86: Mark CR4.TSD as being possibly owned by the guest

2020-07-16T06:13:28+00:00

commit 7c83d096aed055a7763a03384f92115363448b71 upstream.

Mark CR4.TSD as being possibly owned by the guest as that is indeed the
case on VMX.  Without TSD being tagged as possibly owned by the guest, a
targeted read of CR4 to get TSD could observe a stale value.  This bug
is benign in the current code base as the sole consumer of TSD is the
emulator (for RDTSC) and the emulator always "reads" the entirety of CR4
when grabbing bits.

Add a build-time assertion in to ensure VMX doesn't hand over more CR4
bits without also updating x86.

Fixes: 52ce3c21aec3 ("x86,kvm,vmx: Don't trap writes to CR4.TSD")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson 
Message-Id: <20200703040422.31536-2-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini 
Signed-off-by: Greg Kroah-Hartman