commit 41ba17f20ea835c489e77bd54e2da73184e22060 upstream.
Commit <684d984038aa> ('powerpc/powernv: Add debugfs interface for
imc-mode and imc') added debugfs interface for the nest imc pmu
devices to support changing of different ucode modes. Primarily adding
this capability for debug. But when doing so, the code did not
consider the case of cpu-less nodes. So when reading the _cmd_ or
_mode_ file of a cpu-less node will create this crash.
Faulting instruction address: 0xc0000000000d0d58
Oops: Kernel access of bad area, sig: 11 [#1]
...
CPU: 67 PID: 5301 Comm: cat Not tainted 5.2.0-rc6-next-20190627+ #19
NIP: c0000000000d0d58 LR: c00000000049aa18 CTR:c0000000000d0d50
REGS: c00020194548f9e0 TRAP: 0300 Not tainted (5.2.0-rc6-next-20190627+)
MSR: 9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE> CR:28022822 XER: 00000000
CFAR: c00000000049aa14 DAR: 000000000003fc08 DSISR:40000000 IRQMASK: 0
...
NIP imc_mem_get+0x8/0x20
LR simple_attr_read+0x118/0x170
Call Trace:
simple_attr_read+0x70/0x170 (unreliable)
debugfs_attr_read+0x6c/0xb0
__vfs_read+0x3c/0x70
vfs_read+0xbc/0x1a0
ksys_read+0x7c/0x140
system_call+0x5c/0x70
Patch fixes the issue with a more robust check for vbase to NULL.
Before patch, ls output for the debugfs imc directory
# ls /sys/kernel/debug/powerpc/imc/
imc_cmd_0 imc_cmd_251 imc_cmd_253 imc_cmd_255 imc_mode_0 imc_mode_251 imc_mode_253 imc_mode_255
imc_cmd_250 imc_cmd_252 imc_cmd_254 imc_cmd_8 imc_mode_250 imc_mode_252 imc_mode_254 imc_mode_8
After patch, ls output for the debugfs imc directory
# ls /sys/kernel/debug/powerpc/imc/
imc_cmd_0 imc_cmd_8 imc_mode_0 imc_mode_8
Actual bug here is that, we have two loops with potentially different
loop counts. That is, in imc_get_mem_addr_nest(), loop count is
obtained from the dt entries. But in case of export_imc_mode_and_cmd(),
loop was based on for_each_nid() count. Patch fixes the loop count in
latter based on the struct mem_info. Ideally it would be better to
have array size in struct imc_pmu.
Fixes: 684d984038aa ('powerpc/powernv: Add debugfs interface for imc-mode and imc')
Reported-by: Qian Cai <cai@lca.pw>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190827101635.6942-1-maddy@linux.vnet.ibm.com
Cc: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 117acf5c29dd89e4c86761c365b9724dba0d9763 ] Back in 2004 we added logic to arch/ppc64/Makefile to pass the --synthetic option to nm, if it was supported by nm. Then in 2005 when arch/ppc64 and arch/ppc were merged, the logic to add --synthetic was moved inside an #ifdef CONFIG_PPC64 block within arch/powerpc/Makefile, and has remained there since. That was fine, though crufty, until recently when a change to init/Kconfig added a config time check that uses $(NM). On powerpc that leads to an infinite loop because Kconfig uses $(NM) to calculate some values, then the powerpc Makefile changes $(NM), which Kconfig notices and restarts. The original commit that added --synthetic simply said: On new toolchains we need to use nm --synthetic or we miss code symbols. And the nm man page says that the --synthetic option causes nm to: Include synthetic symbols in the output. These are special symbols created by the linker for various purposes. So it seems safe to always pass --synthetic if nm supports it, ie. on 32-bit and 64-bit, it just means 32-bit kernels might have more symbols reported (and in practice I see no extra symbols). Making it unconditional avoids the #ifdef CONFIG_PPC64, which in turn avoids the infinite loop. Debugged-by: Peter Collingbourne <pcc@google.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 6ccb4ac2bf8a35c694ead92f8ac5530a16e8f2c8 upstream.
There's a bug in skiboot that causes the OPAL_XIVE_ALLOCATE_IRQ call
to return the 32-bit value 0xffffffff when OPAL has run out of IRQs.
Unfortunatelty, OPAL return values are signed 64-bit entities and
errors are supposed to be negative. If that happens, the linux code
confusingly treats 0xffffffff as a valid IRQ number and panics at some
point.
A fix was recently merged in skiboot:
e97391ae2bb5 ("xive: fix return value of opal_xive_allocate_irq()")
but we need a workaround anyway to support older skiboots already
in the field.
Internally convert 0xffffffff to OPAL_RESOURCE which is the usual error
returned upon resource exhaustion.
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/156821713818.1985334.14123187368108582810.stgit@bahia.lan
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull powerpc fixes from Michael Ellerman: "One fix for a boot hang on some Freescale machines when PREEMPT is enabled. Two CVE fixes for bugs in our handling of FP registers and transactional memory, both of which can result in corrupted FP state, or FP state leaking between processes. Thanks to: Chris Packham, Christophe Leroy, Gustavo Romero, Michael Neuling" * tag 'powerpc-5.3-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/tm: Fix restoring FP/VMX facility incorrectly on interrupts powerpc/tm: Fix FP/VMX unavailable exceptions inside a transaction powerpc/64e: Drop stale call to smp_processor_id() which hangs SMP startup
When in userspace and MSR FP=0 the hardware FP state is unrelated to
the current process. This is extended for transactions where if tbegin
is run with FP=0, the hardware checkpoint FP state will also be
unrelated to the current process. Due to this, we need to ensure this
hardware checkpoint is updated with the correct state before we enable
FP for this process.
Unfortunately we get this wrong when returning to a process from a
hardware interrupt. A process that starts a transaction with FP=0 can
take an interrupt. When the kernel returns back to that process, we
change to FP=1 but with hardware checkpoint FP state not updated. If
this transaction is then rolled back, the FP registers now contain the
wrong state.
The process looks like this:
Userspace: Kernel
Start userspace
with MSR FP=0 TM=1
< -----
...
tbegin
bne
Hardware interrupt
---- >
<do_IRQ...>
....
ret_from_except
restore_math()
/* sees FP=0 */
restore_fp()
tm_active_with_fp()
/* sees FP=1 (Incorrect) */
load_fp_state()
FP = 0 -> 1
< -----
Return to userspace
with MSR TM=1 FP=1
with junk in the FP TM checkpoint
TM rollback
reads FP junk
When returning from the hardware exception, tm_active_with_fp() is
incorrectly making restore_fp() call load_fp_state() which is setting
FP=1.
The fix is to remove tm_active_with_fp().
tm_active_with_fp() is attempting to handle the case where FP state
has been changed inside a transaction. In this case the checkpointed
and transactional FP state is different and hence we must restore the
FP state (ie. we can't do lazy FP restore inside a transaction that's
used FP). It's safe to remove tm_active_with_fp() as this case is
handled by restore_tm_state(). restore_tm_state() detects if FP has
been using inside a transaction and will set load_fp and call
restore_math() to ensure the FP state (checkpoint and transaction) is
restored.
This is a data integrity problem for the current process as the FP
registers are corrupted. It's also a security problem as the FP
registers from one process may be leaked to another.
Similarly for VMX.
A simple testcase to replicate this will be posted to
tools/testing/selftests/powerpc/tm/tm-poison.c
This fixes CVE-2019-15031.
Fixes: a7771176b439 ("powerpc: Don't enable FP/Altivec if not checkpointed")
Cc: stable@vger.kernel.org # 4.15+
Signed-off-by: Gustavo Romero <gromero@linux.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190904045529.23002-2-gromero@linux.vnet.ibm.com
When we take an FP unavailable exception in a transaction we have to
account for the hardware FP TM checkpointed registers being
incorrect. In this case for this process we know the current and
checkpointed FP registers must be the same (since FP wasn't used
inside the transaction) hence in the thread_struct we copy the current
FP registers to the checkpointed ones.
This copy is done in tm_reclaim_thread(). We use thread->ckpt_regs.msr
to determine if FP was on when in userspace. thread->ckpt_regs.msr
represents the state of the MSR when exiting userspace. This is setup
by check_if_tm_restore_required().
Unfortunatley there is an optimisation in giveup_all() which returns
early if tsk->thread.regs->msr (via local variable `usermsr`) has
FP=VEC=VSX=SPE=0. This optimisation means that
check_if_tm_restore_required() is not called and hence
thread->ckpt_regs.msr is not updated and will contain an old value.
This can happen if due to load_fp=255 we start a userspace process
with MSR FP=1 and then we are context switched out. In this case
thread->ckpt_regs.msr will contain FP=1. If that same process is then
context switched in and load_fp overflows, MSR will have FP=0. If that
process now enters a transaction and does an FP instruction, the FP
unavailable will not update thread->ckpt_regs.msr (the bug) and MSR
FP=1 will be retained in thread->ckpt_regs.msr. tm_reclaim_thread()
will then not perform the required memcpy and the checkpointed FP regs
in the thread struct will contain the wrong values.
The code path for this happening is:
Userspace: Kernel
Start userspace
with MSR FP/VEC/VSX/SPE=0 TM=1
< -----
...
tbegin
bne
fp instruction
FP unavailable
---- >
fp_unavailable_tm()
tm_reclaim_current()
tm_reclaim_thread()
giveup_all()
return early since FP/VMX/VSX=0
/* ckpt MSR not updated (Incorrect) */
tm_reclaim()
/* thread_struct ckpt FP regs contain junk (OK) */
/* Sees ckpt MSR FP=1 (Incorrect) */
no memcpy() performed
/* thread_struct ckpt FP regs not fixed (Incorrect) */
tm_recheckpoint()
/* Put junk in hardware checkpoint FP regs */
....
< -----
Return to userspace
with MSR TM=1 FP=1
with junk in the FP TM checkpoint
TM rollback
reads FP junk
This is a data integrity problem for the current process as the FP
registers are corrupted. It's also a security problem as the FP
registers from one process may be leaked to another.
This patch moves up check_if_tm_restore_required() in giveup_all() to
ensure thread->ckpt_regs.msr is updated correctly.
A simple testcase to replicate this will be posted to
tools/testing/selftests/powerpc/tm/tm-poison.c
Similarly for VMX.
This fixes CVE-2019-15030.
Fixes: f48e91e87e67 ("powerpc/tm: Fix FP and VMX register corruption")
Cc: stable@vger.kernel.org # 4.12+
Signed-off-by: Gustavo Romero <gromero@linux.vnet.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190904045529.23002-1-gromero@linux.vnet.ibm.com
KVM/PPC fix for 5.3 - Fix bug which could leave locks locked in the host on return to a guest.
H_PUT_TCE_INDIRECT handlers receive a page with up to 512 TCEs from
a guest. Although we verify correctness of TCEs before we do anything
with the existing tables, there is a small window when a check in
kvmppc_tce_validate might pass and right after that the guest alters
the page of TCEs, causing an early exit from the handler and leaving
srcu_read_lock(&vcpu->kvm->srcu) (virtual mode) or lock_rmap(rmap)
(real mode) locked.
This fixes the bug by jumping to the common exit code with an appropriate
unlock.
Cc: stable@vger.kernel.org # v4.11+
Fixes: 121f80ba68f1 ("KVM: PPC: VFIO: Add in-kernel acceleration for VFIO")
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Pull dma-mapping fixes from Christoph Hellwig: - fix the handling of the bus_dma_mask in dma_get_required_mask, which caused a regression in this merge window (Lucas Stach) - fix a regression in the handling of DMA_ATTR_NO_KERNEL_MAPPING (me) - fix dma_mmap_coherent to not cause page attribute mismatches on coherent architectures like x86 (me) * tag 'dma-mapping-5.3-4' of git://git.infradead.org/users/hch/dma-mapping: dma-mapping: fix page attributes for dma_mmap_* dma-direct: don't truncate dma_required_mask to bus addressing capabilities dma-direct: fix DMA_ATTR_NO_KERNEL_MAPPING
Commit ebb9d30a6a74 ("powerpc/mm: any thread in one core can be the
first to setup TLB1") removed the need to know the cpu_id in
early_init_this_mmu(), but the call to smp_processor_id() which was
marked __maybe_used remained.
Since commit ed1cd6deb013 ("powerpc: Activate CONFIG_THREAD_INFO_IN_TASK")
thread_info cannot be reached before MMU is properly set up.
Drop this stale call to smp_processor_id() which makes SMP hang when
CONFIG_PREEMPT is set.
Fixes: ebb9d30a6a74 ("powerpc/mm: any thread in one core can be the first to setup TLB1")
Fixes: ed1cd6deb013 ("powerpc: Activate CONFIG_THREAD_INFO_IN_TASK")
Cc: stable@vger.kernel.org # v5.1+
Reported-by: Chris Packham <Chris.Packham@alliedtelesis.co.nz>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Tested-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bef479514f4c08329fa649f67735df8918bc0976.1565268248.git.christophe.leroy@c-s.fr