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  1. 15 5月, 2019 1 次提交
    • J
      powerpc/speculation: Support 'mitigations=' cmdline option · 74857f69
      由 Josh Poimboeuf 提交于 
      commit 782e69efb3dfed6e8360bc612e8c7827a901a8f9 upstream

Configure powerpc CPU runtime speculation bug mitigations in accordance
with the 'mitigations=' cmdline option.  This affects Meltdown, Spectre
v1, Spectre v2, and Speculative Store Bypass.

The default behavior is unchanged.
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86)
Reviewed-by: NJiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Phil Auld <pauld@redhat.com>
Link: https://lkml.kernel.org/r/245a606e1a42a558a310220312d9b6adb9159df6.1555085500.git.jpoimboe@redhat.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      74857f69
  3. 08 5月, 2019 2 次提交
  5. 02 5月, 2019 2 次提交
    • M
      powerpc/mm/radix: Make Radix require HUGETLB_PAGE · 087341c0
      由 Michael Ellerman 提交于 
      commit 8adddf349fda0d3de2f6bb41ddf838cbf36a8ad2 upstream.

Joel reported weird crashes using skiroot_defconfig, in his case we
jumped into an NX page:

  kernel tried to execute exec-protected page (c000000002bff4f0) - exploit attempt? (uid: 0)
  BUG: Unable to handle kernel instruction fetch
  Faulting instruction address: 0xc000000002bff4f0

Looking at the disassembly, we had simply branched to that address:

  c000000000c001bc  49fff335    bl     c000000002bff4f0

But that didn't match the original kernel image:

  c000000000c001bc  4bfff335    bl     c000000000bff4f0 <kobject_get+0x8>

When STRICT_KERNEL_RWX is enabled, and we're using the radix MMU, we
call radix__change_memory_range() late in boot to change page
protections. We do that both to mark rodata read only and also to mark
init text no-execute. That involves walking the kernel page tables,
and clearing _PAGE_WRITE or _PAGE_EXEC respectively.

With radix we may use hugepages for the linear mapping, so the code in
radix__change_memory_range() uses eg. pmd_huge() to test if it has
found a huge mapping, and if so it stops the page table walk and
changes the PMD permissions.

However if the kernel is built without HUGETLBFS support, pmd_huge()
is just a #define that always returns 0. That causes the code in
radix__change_memory_range() to incorrectly interpret the PMD value as
a pointer to a PTE page rather than as a PTE at the PMD level.

We can see this using `dv` in xmon which also uses pmd_huge():

  0:mon> dv c000000000000000
  pgd  @ 0xc000000001740000
  pgdp @ 0xc000000001740000 = 0x80000000ffffb009
  pudp @ 0xc0000000ffffb000 = 0x80000000ffffa009
  pmdp @ 0xc0000000ffffa000 = 0xc00000000000018f   <- this is a PTE
  ptep @ 0xc000000000000100 = 0xa64bb17da64ab07d   <- kernel text

The end result is we treat the value at 0xc000000000000100 as a PTE
and clear _PAGE_WRITE or _PAGE_EXEC, potentially corrupting the code
at that address.

In Joel's specific case we cleared the sign bit in the offset of the
branch, causing a backward branch to turn into a forward branch which
caused us to branch into a non-executable page. However the exact
nature of the crash depends on kernel version, compiler version, and
other factors.

We need to fix radix__change_memory_range() to not use accessors that
depend on HUGETLBFS, but we also have radix memory hotplug code that
uses pmd_huge() etc that will also need fixing. So for now just
disallow the broken combination of Radix with HUGETLBFS disabled.

The only defconfig we have that is affected is skiroot_defconfig, so
turn on HUGETLBFS there so that it still gets Radix.

Fixes: 566ca99a ("powerpc/mm/radix: Add dummy radix_enabled()")
Cc: stable@vger.kernel.org # v4.7+
Reported-by: NJoel Stanley <joel@jms.id.au>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      087341c0
    • C
      powerpc/vdso32: fix CLOCK_MONOTONIC on PPC64 · 1e0cab1b
      由 Christophe Leroy 提交于 
      [ Upstream commit dd9a994fc68d196a052b73747e3366c57d14a09e ]

Commit b5b4453e7912 ("powerpc/vdso64: Fix CLOCK_MONOTONIC
inconsistencies across Y2038") changed the type of wtom_clock_sec
to s64 on PPC64. Therefore, VDSO32 needs to read it with a 4 bytes
shift in order to retrieve the lower part of it.

Fixes: b5b4453e7912 ("powerpc/vdso64: Fix CLOCK_MONOTONIC inconsistencies across Y2038")
Reported-by: NChristian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NSasha Levin <sashal@kernel.org>
      1e0cab1b
  7. 20 4月, 2019 1 次提交
    • N
      powerpc/pseries: Remove prrn_work workqueue · 6947d853
      由 Nathan Fontenot 提交于 
      [ Upstream commit cd24e457fd8b2d087d9236700c8d2957054598bf ]

When a PRRN event is received we are already running in a worker
thread. Instead of spawning off another worker thread on the prrn_work
workqueue to handle the PRRN event we can just call the PRRN handler
routine directly.

With this update we can also pass the scope variable for the PRRN
event directly to the handler instead of it being a global variable.

This patch fixes the following oops mnessage we are seeing in PRRN testing:

  Oops: Bad kernel stack pointer, sig: 6 [#1]
  SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in: nfsv3 nfs_acl rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace sunrpc fscache binfmt_misc reiserfs vfat fat rpadlpar_io(X) rpaphp(X) tcp_diag udp_diag inet_diag unix_diag af_packet_diag netlink_diag af_packet xfs libcrc32c dm_service_time ibmveth(X) ses enclosure scsi_transport_sas rtc_generic btrfs xor raid6_pq sd_mod ibmvscsi(X) scsi_transport_srp ipr(X) libata sg dm_multipath dm_mod scsi_dh_rdac scsi_dh_emc scsi_dh_alua scsi_mod autofs4
  Supported: Yes, External                                                     54
  CPU: 7 PID: 18967 Comm: kworker/u96:0 Tainted: G                 X 4.4.126-94.22-default #1
  Workqueue: pseries hotplug workque pseries_hp_work_fn
  task: c000000775367790 ti: c00000001ebd4000 task.ti: c00000070d140000
  NIP: 0000000000000000 LR: 000000001fb3d050 CTR: 0000000000000000
  REGS: c00000001ebd7d40 TRAP: 0700   Tainted: G                 X  (4.4.126-94.22-default)
  MSR: 8000000102081000 <41,VEC,ME5  CR: 28000002  XER: 20040018   4
  CFAR: 000000001fb3d084 40 419   1                                3
  GPR00: 000000000000000040000000000010007 000000001ffff400 000000041fffe200
  GPR04: 000000000000008050000000000000000 000000001fb15fa8 0000000500000500
  GPR08: 000000000001f40040000000000000001 0000000000000000 000005:5200040002
  GPR12: 00000000000000005c000000007a05400 c0000000000e89f8 000000001ed9f668
  GPR16: 000000001fbeff944000000001fbeff94 000000001fb545e4 0000006000000060
  GPR20: ffffffffffffffff4ffffffffffffffff 0000000000000000 0000000000000000
  GPR24: 00000000000000005400000001fb3c000 0000000000000000 000000001fb1b040
  GPR28: 000000001fb240004000000001fb440d8 0000000000000008 0000000000000000
  NIP [0000000000000000] 5         (null)
  LR [000000001fb3d050] 031fb3d050
  Call Trace:            4
  Instruction dump:      4                                       5:47 12    2
  XXXXXXXX XXXXXXXX XXXXX4XX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
  XXXXXXXX XXXXXXXX XXXXX5XX XXXXXXXX 60000000 60000000 60000000 60000000
  ---[ end trace aa5627b04a7d9d6b ]---                                       3NMI watchdog: BUG: soft lockup - CPU#27 stuck for 23s! [kworker/27:0:13903]
  Modules linked in: nfsv3 nfs_acl rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace sunrpc fscache binfmt_misc reiserfs vfat fat rpadlpar_io(X) rpaphp(X) tcp_diag udp_diag inet_diag unix_diag af_packet_diag netlink_diag af_packet xfs libcrc32c dm_service_time ibmveth(X) ses enclosure scsi_transport_sas rtc_generic btrfs xor raid6_pq sd_mod ibmvscsi(X) scsi_transport_srp ipr(X) libata sg dm_multipath dm_mod scsi_dh_rdac scsi_dh_emc scsi_dh_alua scsi_mod autofs4
  Supported: Yes, External
  CPU: 27 PID: 13903 Comm: kworker/27:0 Tainted: G      D          X 4.4.126-94.22-default #1
  Workqueue: events prrn_work_fn
  task: c000000747cfa390 ti: c00000074712c000 task.ti: c00000074712c000
  NIP: c0000000008002a8 LR: c000000000090770 CTR: 000000000032e088
  REGS: c00000074712f7b0 TRAP: 0901   Tainted: G      D          X  (4.4.126-94.22-default)
  MSR: 8000000100009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 22482044  XER: 20040000
  CFAR: c0000000008002c4 SOFTE: 1
  GPR00: c000000000090770 c00000074712fa30 c000000000f09800 c000000000fa1928 6:02
  GPR04: c000000775f5e000 fffffffffffffffe 0000000000000001 c000000000f42db8
  GPR08: 0000000000000001 0000000080000007 0000000000000000 0000000000000000
  GPR12: 8006210083180000 c000000007a14400
  NIP [c0000000008002a8] _raw_spin_lock+0x68/0xd0
  LR [c000000000090770] mobility_rtas_call+0x50/0x100
  Call Trace:            59                                        5
  [c00000074712fa60] [c000000000090770] mobility_rtas_call+0x50/0x100
  [c00000074712faf0] [c000000000090b08] pseries_devicetree_update+0xf8/0x530
  [c00000074712fc20] [c000000000031ba4] prrn_work_fn+0x34/0x50
  [c00000074712fc40] [c0000000000e0390] process_one_work+0x1a0/0x4e0
  [c00000074712fcd0] [c0000000000e0870] worker_thread+0x1a0/0x6105:57       2
  [c00000074712fd80] [c0000000000e8b18] kthread+0x128/0x150
  [c00000074712fe30] [c0000000000096f8] ret_from_kernel_thread+0x5c/0x64
  Instruction dump:
  2c090000 40c20010 7d40192d 40c2fff0 7c2004ac 2fa90000 40de0018 5:540030   3
  e8010010 ebe1fff8 7c0803a6 4e800020 <7c210b78> e92d0000 89290009 792affe3
Signed-off-by: NJohn Allen <jallen@linux.ibm.com>
Signed-off-by: NHaren Myneni <haren@us.ibm.com>
Signed-off-by: NNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NSasha Levin <sashal@kernel.org>
      6947d853
  9. 17 4月, 2019 1 次提交
    • B
      powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM · 902eca1a
      由 Breno Leitao 提交于 
      commit 897bc3df8c5aebb54c32d831f917592e873d0559 upstream.

Commit e1c3743e1a20 ("powerpc/tm: Set MSR[TS] just prior to recheckpoint")
moved a code block around and this block uses a 'msr' variable outside of
the CONFIG_PPC_TRANSACTIONAL_MEM, however the 'msr' variable is declared
inside a CONFIG_PPC_TRANSACTIONAL_MEM block, causing a possible error when
CONFIG_PPC_TRANSACTION_MEM is not defined.

	error: 'msr' undeclared (first use in this function)

This is not causing a compilation error in the mainline kernel, because
'msr' is being used as an argument of MSR_TM_ACTIVE(), which is defined as
the following when CONFIG_PPC_TRANSACTIONAL_MEM is *not* set:

	#define MSR_TM_ACTIVE(x) 0

This patch just fixes this issue avoiding the 'msr' variable usage outside
the CONFIG_PPC_TRANSACTIONAL_MEM block, avoiding trusting in the
MSR_TM_ACTIVE() definition.

Cc: stable@vger.kernel.org
Reported-by: NChristoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Fixes: e1c3743e1a20 ("powerpc/tm: Set MSR[TS] just prior to recheckpoint")
Signed-off-by: NBreno Leitao <leitao@debian.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
      902eca1a
  11. 06 4月, 2019 5 次提交
    • N
      powerpc/pseries: Perform full re-add of CPU for topology update post-migration · 06af7dda
      由 Nathan Fontenot 提交于 
      [ Upstream commit 81b61324922c67f73813d8a9c175f3c153f6a1c6 ]

On pseries systems, performing a partition migration can result in
altering the nodes a CPU is assigned to on the destination system. For
exampl, pre-migration on the source system CPUs are in node 1 and 3,
post-migration on the destination system CPUs are in nodes 2 and 3.

Handling the node change for a CPU can cause corruption in the slab
cache if we hit a timing where a CPUs node is changed while cache_reap()
is invoked. The corruption occurs because the slab cache code appears
to rely on the CPU and slab cache pages being on the same node.

The current dynamic updating of a CPUs node done in arch/powerpc/mm/numa.c
does not prevent us from hitting this scenario.

Changing the device tree property update notification handler that
recognizes an affinity change for a CPU to do a full DLPAR remove and
add of the CPU instead of dynamically changing its node resolves this
issue.
Signed-off-by: NNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: NMichael W. Bringmann <mwb@linux.vnet.ibm.com>
Tested-by: NMichael W. Bringmann <mwb@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NSasha Levin <sashal@kernel.org>
      06af7dda
    • N
      powerpc/64s: Clear on-stack exception marker upon exception return · b52681e6
      由 Nicolai Stange 提交于 
      [ Upstream commit eddd0b332304d554ad6243942f87c2fcea98c56b ]

The ppc64 specific implementation of the reliable stacktracer,
save_stack_trace_tsk_reliable(), bails out and reports an "unreliable
trace" whenever it finds an exception frame on the stack. Stack frames
are classified as exception frames if the STACK_FRAME_REGS_MARKER
magic, as written by exception prologues, is found at a particular
location.

However, as observed by Joe Lawrence, it is possible in practice that
non-exception stack frames can alias with prior exception frames and
thus, that the reliable stacktracer can find a stale
STACK_FRAME_REGS_MARKER on the stack. It in turn falsely reports an
unreliable stacktrace and blocks any live patching transition to
finish. Said condition lasts until the stack frame is
overwritten/initialized by function call or other means.

In principle, we could mitigate this by making the exception frame
classification condition in save_stack_trace_tsk_reliable() stronger:
in addition to testing for STACK_FRAME_REGS_MARKER, we could also take
into account that for all exceptions executing on the kernel stack
  - their stack frames's backlink pointers always match what is saved
    in their pt_regs instance's ->gpr[1] slot and that
  - their exception frame size equals STACK_INT_FRAME_SIZE, a value
    uncommonly large for non-exception frames.

However, while these are currently true, relying on them would make
the reliable stacktrace implementation more sensitive towards future
changes in the exception entry code. Note that false negatives, i.e.
not detecting exception frames, would silently break the live patching
consistency model.

Furthermore, certain other places (diagnostic stacktraces, perf, xmon)
rely on STACK_FRAME_REGS_MARKER as well.

Make the exception exit code clear the on-stack
STACK_FRAME_REGS_MARKER for those exceptions running on the "normal"
kernel stack and returning to kernelspace: because the topmost frame
is ignored by the reliable stack tracer anyway, returns to userspace
don't need to take care of clearing the marker.

Furthermore, as I don't have the ability to test this on Book 3E or 32
bits, limit the change to Book 3S and 64 bits.

Fixes: df78d3f6 ("powerpc/livepatch: Implement reliable stack tracing for the consistency model")
Reported-by: NJoe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: NNicolai Stange <nstange@suse.de>
Signed-off-by: NJoe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NSasha Levin <sashal@kernel.org>
      b52681e6
    • A
      powerpc/hugetlb: Handle mmap_min_addr correctly in get_unmapped_area callback · 6cf5f631
      由 Aneesh Kumar K.V 提交于 
      [ Upstream commit 5330367fa300742a97e20e953b1f77f48392faae ]

After we ALIGN up the address we need to make sure we didn't overflow
and resulted in zero address. In that case, we need to make sure that
the returned address is greater than mmap_min_addr.

This fixes selftest va_128TBswitch --run-hugetlb reporting failures when
run as non root user for

mmap(-1, MAP_HUGETLB)

The bug is that a non-root user requesting address -1 will be given address 0
which will then fail, whereas they should have been given something else that
would have succeeded.

We also avoid the first mmap(-1, MAP_HUGETLB) returning NULL address as mmap address
with this change. So we think this is not a security issue, because it only affects
whether we choose an address below mmap_min_addr, not whether we
actually allow that address to be mapped. ie. there are existing capability
checks to prevent a user mapping below mmap_min_addr and those will still be
honoured even without this fix.

Fixes: 48483760 ("powerpc/mm: Add radix support for hugetlb")
Reviewed-by: NLaurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NSasha Levin <sashal@kernel.org>
      6cf5f631
    • N
      powerpc/xmon: Fix opcode being uninitialized in print_insn_powerpc · c70214d5
      由 Nathan Chancellor 提交于 
      [ Upstream commit e7140639b1de65bba435a6bd772d134901141f86 ]

When building with -Wsometimes-uninitialized, Clang warns:

  arch/powerpc/xmon/ppc-dis.c:157:7: warning: variable 'opcode' is used
  uninitialized whenever 'if' condition is false
  [-Wsometimes-uninitialized]
    if (cpu_has_feature(CPU_FTRS_POWER9))
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  arch/powerpc/xmon/ppc-dis.c:167:7: note: uninitialized use occurs here
    if (opcode == NULL)
        ^~~~~~
  arch/powerpc/xmon/ppc-dis.c:157:3: note: remove the 'if' if its
  condition is always true
    if (cpu_has_feature(CPU_FTRS_POWER9))
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  arch/powerpc/xmon/ppc-dis.c:132:38: note: initialize the variable
  'opcode' to silence this warning
    const struct powerpc_opcode *opcode;
                                       ^
                                        = NULL
  1 warning generated.

This warning seems to make no sense on the surface because opcode is set
to NULL right below this statement. However, there is a comma instead of
semicolon to end the dialect assignment, meaning that the opcode
assignment only happens in the if statement. Properly terminate that
line so that Clang no longer warns.

Fixes: 5b102782 ("powerpc/xmon: Enable disassembly files (compilation changes)")
Signed-off-by: NNathan Chancellor <natechancellor@gmail.com>
Reviewed-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NSasha Levin <sashal@kernel.org>
      c70214d5
    • A
      powerpc/powernv/ioda: Fix locked_vm counting for memory used by IOMMU tables · 4acf7974
      由 Alexey Kardashevskiy 提交于 
      [ Upstream commit 11f5acce2fa43b015a8120fa7620fa4efd0a2952 ]

We store 2 multilevel tables in iommu_table - one for the hardware and
one with the corresponding userspace addresses. Before allocating
the tables, the iommu_table_group_ops::get_table_size() hook returns
the combined size of the two and VFIO SPAPR TCE IOMMU driver adjusts
the locked_vm counter correctly. When the table is actually allocated,
the amount of allocated memory is stored in iommu_table::it_allocated_size
and used to decrement the locked_vm counter when we release the memory
used by the table; .get_table_size() and .create_table() calculate it
independently but the result is expected to be the same.

However the allocator does not add the userspace table size to
.it_allocated_size so when we destroy the table because of VFIO PCI
unplug (i.e. VFIO container is gone but the userspace keeps running),
we decrement locked_vm by just a half of size of memory we are
releasing.

To make things worse, since we enabled on-demand allocation of
indirect levels, it_allocated_size contains only the amount of memory
actually allocated at the table creation time which can just be a
fraction. It is not a problem with incrementing locked_vm (as
get_table_size() value is used) but it is with decrementing.

As the result, we leak locked_vm and may not be able to allocate more
IOMMU tables after few iterations of hotplug/unplug.

This sets it_allocated_size in the pnv_pci_ioda2_ops::create_table()
hook to what pnv_pci_ioda2_get_table_size() returns so from now on we
have a single place which calculates the maximum memory a table can
occupy. The original meaning of it_allocated_size is somewhat lost now
though.

We do not ditch it_allocated_size whatsoever here and we do not call
get_table_size() from vfio_iommu_spapr_tce.c when decrementing
locked_vm as we may have multiple IOMMU groups per container and even
though they all are supposed to have the same get_table_size()
implementation, there is a small chance for failure or confusion.

Fixes: 090bad39 ("powerpc/powernv: Add indirect levels to it_userspace")
Signed-off-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NSasha Levin <sashal@kernel.org>
      4acf7974
  13. 03 4月, 2019 15 次提交
  15. 27 3月, 2019 1 次提交
    • M
      powerpc/vdso64: Fix CLOCK_MONOTONIC inconsistencies across Y2038 · b8ea151a
      由 Michael Ellerman 提交于 
      commit b5b4453e7912f056da1ca7572574cada32ecb60c upstream.

Jakub Drnec reported:
  Setting the realtime clock can sometimes make the monotonic clock go
  back by over a hundred years. Decreasing the realtime clock across
  the y2k38 threshold is one reliable way to reproduce. Allegedly this
  can also happen just by running ntpd, I have not managed to
  reproduce that other than booting with rtc at >2038 and then running
  ntp. When this happens, anything with timers (e.g. openjdk) breaks
  rather badly.

And included a test case (slightly edited for brevity):
  #define _POSIX_C_SOURCE 199309L
  #include <stdio.h>
  #include <time.h>
  #include <stdlib.h>
  #include <unistd.h>

  long get_time(void) {
    struct timespec tp;
    clock_gettime(CLOCK_MONOTONIC, &tp);
    return tp.tv_sec + tp.tv_nsec / 1000000000;
  }

  int main(void) {
    long last = get_time();
    while(1) {
      long now = get_time();
      if (now < last) {
        printf("clock went backwards by %ld seconds!\n", last - now);
      }
      last = now;
      sleep(1);
    }
    return 0;
  }

Which when run concurrently with:
 # date -s 2040-1-1
 # date -s 2037-1-1

Will detect the clock going backward.

The root cause is that wtom_clock_sec in struct vdso_data is only a
32-bit signed value, even though we set its value to be equal to
tk->wall_to_monotonic.tv_sec which is 64-bits.

Because the monotonic clock starts at zero when the system boots the
wall_to_montonic.tv_sec offset is negative for current and future
dates. Currently on a freshly booted system the offset will be in the
vicinity of negative 1.5 billion seconds.

However if the wall clock is set past the Y2038 boundary, the offset
from wall to monotonic becomes less than negative 2^31, and no longer
fits in 32-bits. When that value is assigned to wtom_clock_sec it is
truncated and becomes positive, causing the VDSO assembly code to
calculate CLOCK_MONOTONIC incorrectly.

That causes CLOCK_MONOTONIC to jump ahead by ~4 billion seconds which
it is not meant to do. Worse, if the time is then set back before the
Y2038 boundary CLOCK_MONOTONIC will jump backward.

We can fix it simply by storing the full 64-bit offset in the
vdso_data, and using that in the VDSO assembly code. We also shuffle
some of the fields in vdso_data to avoid creating a hole.

The original commit that added the CLOCK_MONOTONIC support to the VDSO
did actually use a 64-bit value for wtom_clock_sec, see commit
a7f290da ("[PATCH] powerpc: Merge vdso's and add vdso support to
32 bits kernel") (Nov 2005). However just 3 days later it was
converted to 32-bits in commit 0c37ec2a ("[PATCH] powerpc: vdso
fixes (take #2)"), and the bug has existed since then AFAICS.

Fixes: 0c37ec2a ("[PATCH] powerpc: vdso fixes (take #2)")
Cc: stable@vger.kernel.org # v2.6.15+
Link: http://lkml.kernel.org/r/HaC.ZfES.62bwlnvAvMP.1STMMj@seznam.czReported-by: NJakub Drnec <jaydee@email.cz>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b8ea151a
  17. 24 3月, 2019 11 次提交
    • S
      KVM: Call kvm_arch_memslots_updated() before updating memslots · 23ad135a
      由 Sean Christopherson 提交于 
      commit 152482580a1b0accb60676063a1ac57b2d12daf6 upstream.

kvm_arch_memslots_updated() is at this point in time an x86-specific
hook for handling MMIO generation wraparound.  x86 stashes 19 bits of
the memslots generation number in its MMIO sptes in order to avoid
full page fault walks for repeat faults on emulated MMIO addresses.
Because only 19 bits are used, wrapping the MMIO generation number is
possible, if unlikely.  kvm_arch_memslots_updated() alerts x86 that
the generation has changed so that it can invalidate all MMIO sptes in
case the effective MMIO generation has wrapped so as to avoid using a
stale spte, e.g. a (very) old spte that was created with generation==0.

Given that the purpose of kvm_arch_memslots_updated() is to prevent
consuming stale entries, it needs to be called before the new generation
is propagated to memslots.  Invalidating the MMIO sptes after updating
memslots means that there is a window where a vCPU could dereference
the new memslots generation, e.g. 0, and incorrectly reuse an old MMIO
spte that was created with (pre-wrap) generation==0.

Fixes: e59dbe09 ("KVM: Introduce kvm_arch_memslots_updated()")
Cc: <stable@vger.kernel.org>
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      23ad135a
    • C
      powerpc/traps: Fix the message printed when stack overflows · d6d004b3
      由 Christophe Leroy 提交于 
      commit 9bf3d3c4e4fd82c7174f4856df372ab2a71005b9 upstream.

Today's message is useless:

  [   42.253267] Kernel stack overflow in process (ptrval), r1=c65500b0

This patch fixes it:

  [   66.905235] Kernel stack overflow in process sh[356], r1=c65560b0

Fixes: ad67b74d ("printk: hash addresses printed with %p")
Cc: stable@vger.kernel.org # v4.15+
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
[mpe: Use task_pid_nr()]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      d6d004b3
    • C
      powerpc/traps: fix recoverability of machine check handling on book3s/32 · 461a52a4
      由 Christophe Leroy 提交于 
      commit 0bbea75c476b77fa7d7811d6be911cc7583e640f upstream.

Looks like book3s/32 doesn't set RI on machine check, so
checking RI before calling die() will always be fatal
allthought this is not an issue in most cases.

Fixes: b96672dd ("powerpc: Machine check interrupt is a non-maskable interrupt")
Fixes: daf00ae71dad ("powerpc/traps: restore recoverability of machine_check interrupts")
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Cc: stable@vger.kernel.org
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      461a52a4
    • A
      powerpc/hugetlb: Don't do runtime allocation of 16G pages in LPAR configuration · baed68a9
      由 Aneesh Kumar K.V 提交于 
      commit 35f2806b481f5b9207f25e1886cba5d1c4d12cc7 upstream.

We added runtime allocation of 16G pages in commit 4ae279c2
("powerpc/mm/hugetlb: Allow runtime allocation of 16G.") That was done
to enable 16G allocation on PowerNV and KVM config. In case of KVM
config, we mostly would have the entire guest RAM backed by 16G
hugetlb pages for this to work. PAPR do support partial backing of
guest RAM with hugepages via ibm,expected#pages node of memory node in
the device tree. This means rest of the guest RAM won't be backed by
16G contiguous pages in the host and hence a hash page table insertion
can fail in such case.

An example error message will look like

  hash-mmu: mm: Hashing failure ! EA=0x7efc00000000 access=0x8000000000000006 current=readback
  hash-mmu:     trap=0x300 vsid=0x67af789 ssize=1 base psize=14 psize 14 pte=0xc000000400000386
  readback[12260]: unhandled signal 7 at 00007efc00000000 nip 00000000100012d0 lr 000000001000127c code 2

This patch address that by preventing runtime allocation of 16G
hugepages in LPAR config. To allocate 16G hugetlb one need to kernel
command line hugepagesz=16G hugepages=<number of 16G pages>

With radix translation mode we don't run into this issue.

This change will prevent runtime allocation of 16G hugetlb pages on
kvm with hash translation mode. However, with the current upstream it
was observed that 16G hugetlbfs backed guest doesn't boot at all.

We observe boot failure with the below message:
  [131354.647546] KVM: map_vrma at 0 failed, ret=-4

That means this patch is not resulting in an observable regression.
Once we fix the boot issue with 16G hugetlb backed memory, we need to
use ibm,expected#pages memory node attribute to indicate 16G page
reservation to the guest. This will also enable partial backing of
guest RAM with 16G pages.

Fixes: 4ae279c2 ("powerpc/mm/hugetlb: Allow runtime allocation of 16G.")
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      baed68a9
    • M
      powerpc/ptrace: Simplify vr_get/set() to avoid GCC warning · 9d2e929c
      由 Michael Ellerman 提交于 
      commit ca6d5149d2ad0a8d2f9c28cbe379802260a0a5e0 upstream.

GCC 8 warns about the logic in vr_get/set(), which with -Werror breaks
the build:

  In function ‘user_regset_copyin’,
      inlined from ‘vr_set’ at arch/powerpc/kernel/ptrace.c:628:9:
  include/linux/regset.h:295:4: error: ‘memcpy’ offset [-527, -529] is
  out of the bounds [0, 16] of object ‘vrsave’ with type ‘union
  <anonymous>’ [-Werror=array-bounds]
  arch/powerpc/kernel/ptrace.c: In function ‘vr_set’:
  arch/powerpc/kernel/ptrace.c:623:5: note: ‘vrsave’ declared here
     } vrsave;

This has been identified as a regression in GCC, see GCC bug 88273.

However we can avoid the warning and also simplify the logic and make
it more robust.

Currently we pass -1 as end_pos to user_regset_copyout(). This says
"copy up to the end of the regset".

The definition of the regset is:
	[REGSET_VMX] = {
		.core_note_type = NT_PPC_VMX, .n = 34,
		.size = sizeof(vector128), .align = sizeof(vector128),
		.active = vr_active, .get = vr_get, .set = vr_set
	},

The end is calculated as (n * size), ie. 34 * sizeof(vector128).

In vr_get/set() we pass start_pos as 33 * sizeof(vector128), meaning
we can copy up to sizeof(vector128) into/out-of vrsave.

The on-stack vrsave is defined as:
  union {
	  elf_vrreg_t reg;
	  u32 word;
  } vrsave;

And elf_vrreg_t is:
  typedef __vector128 elf_vrreg_t;

So there is no bug, but we rely on all those sizes lining up,
otherwise we would have a kernel stack exposure/overwrite on our
hands.

Rather than relying on that we can pass an explict end_pos based on
the sizeof(vrsave). The result should be exactly the same but it's
more obviously not over-reading/writing the stack and it avoids the
compiler warning.
Reported-by: NMeelis Roos <mroos@linux.ee>
Reported-by: NMathieu Malaterre <malat@debian.org>
Cc: stable@vger.kernel.org
Tested-by: NMathieu Malaterre <malat@debian.org>
Tested-by: NMeelis Roos <mroos@linux.ee>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      9d2e929c
    • M
      powerpc: Fix 32-bit KVM-PR lockup and host crash with MacOS guest · 344996a8
      由 Mark Cave-Ayland 提交于 
      commit fe1ef6bcdb4fca33434256a802a3ed6aacf0bd2f upstream.

Commit 8792468d "powerpc: Add the ability to save FPU without
giving it up" unexpectedly removed the MSR_FE0 and MSR_FE1 bits from
the bitmask used to update the MSR of the previous thread in
__giveup_fpu() causing a KVM-PR MacOS guest to lockup and panic the
host kernel.

Leaving FE0/1 enabled means unrelated processes might receive FPEs
when they're not expecting them and crash. In particular if this
happens to init the host will then panic.

eg (transcribed):
  qemu-system-ppc[837]: unhandled signal 8 at 12cc9ce4 nip 12cc9ce4 lr 12cc9ca4 code 0
  systemd[1]: unhandled signal 8 at 202f02e0 nip 202f02e0 lr 001003d4 code 0
  Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

Reinstate these bits to the MSR bitmask to enable MacOS guests to run
under 32-bit KVM-PR once again without issue.

Fixes: 8792468d ("powerpc: Add the ability to save FPU without giving it up")
Cc: stable@vger.kernel.org # v4.6+
Signed-off-by: NMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      344996a8
    • P
      powerpc/powernv: Don't reprogram SLW image on every KVM guest entry/exit · 3bf8ff7b
      由 Paul Mackerras 提交于 
      commit 19f8a5b5be2898573a5e1dc1db93e8d40117606a upstream.

Commit 24be85a2 ("powerpc/powernv: Clear PECE1 in LPCR via stop-api
only on Hotplug", 2017-07-21) added two calls to opal_slw_set_reg()
inside pnv_cpu_offline(), with the aim of changing the LPCR value in
the SLW image to disable wakeups from the decrementer while a CPU is
offline.  However, pnv_cpu_offline() gets called each time a secondary
CPU thread is woken up to participate in running a KVM guest, that is,
not just when a CPU is offlined.

Since opal_slw_set_reg() is a very slow operation (with observed
execution times around 20 milliseconds), this means that an offline
secondary CPU can often be busy doing the opal_slw_set_reg() call
when the primary CPU wants to grab all the secondary threads so that
it can run a KVM guest.  This leads to messages like "KVM: couldn't
grab CPU n" being printed and guest execution failing.

There is no need to reprogram the SLW image on every KVM guest entry
and exit.  So that we do it only when a CPU is really transitioning
between online and offline, this moves the calls to
pnv_program_cpu_hotplug_lpcr() into pnv_smp_cpu_kill_self().

Fixes: 24be85a2 ("powerpc/powernv: Clear PECE1 in LPCR via stop-api only on Hotplug")
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      3bf8ff7b
    • C
      powerpc/83xx: Also save/restore SPRG4-7 during suspend · f6f03d60
      由 Christophe Leroy 提交于 
      commit 36da5ff0bea2dc67298150ead8d8471575c54c7d upstream.

The 83xx has 8 SPRG registers and uses at least SPRG4
for DTLB handling LRU.

Fixes: 2319f123 ("powerpc/mm: e300c2/c3/c4 TLB errata workaround")
Cc: stable@vger.kernel.org
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      f6f03d60
    • J
      powerpc/powernv: Make opal log only readable by root · b0934990
      由 Jordan Niethe 提交于 
      commit 7b62f9bd2246b7d3d086e571397c14ba52645ef1 upstream.

Currently the opal log is globally readable. It is kernel policy to
limit the visibility of physical addresses / kernel pointers to root.
Given this and the fact the opal log may contain this information it
would be better to limit the readability to root.

Fixes: bfc36894 ("powerpc/powernv: Add OPAL message log interface")
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: NJordan Niethe <jniethe5@gmail.com>
Reviewed-by: NStewart Smith <stewart@linux.ibm.com>
Reviewed-by: NAndrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b0934990
    • C
      powerpc/wii: properly disable use of BATs when requested. · 9b530550
      由 Christophe Leroy 提交于 
      commit 6d183ca8baec983dc4208ca45ece3c36763df912 upstream.

'nobats' kernel parameter or some options like CONFIG_DEBUG_PAGEALLOC
deny the use of BATS for mapping memory.

This patch makes sure that the specific wii RAM mapping function
takes it into account as well.

Fixes: de32400d ("wii: use both mem1 and mem2 as ram")
Cc: stable@vger.kernel.org
Reviewed-by: NJonathan Neuschafer <j.neuschaefer@gmx.net>
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      9b530550
    • C
      powerpc/32: Clear on-stack exception marker upon exception return · 40b97853
      由 Christophe Leroy 提交于 
      commit 9580b71b5a7863c24a9bd18bcd2ad759b86b1eff upstream.

Clear the on-stack STACK_FRAME_REGS_MARKER on exception exit in order
to avoid confusing stacktrace like the one below.

  Call Trace:
  [c0e9dca0] [c01c42a0] print_address_description+0x64/0x2bc (unreliable)
  [c0e9dcd0] [c01c4684] kasan_report+0xfc/0x180
  [c0e9dd10] [c0895130] memchr+0x24/0x74
  [c0e9dd30] [c00a9e38] msg_print_text+0x124/0x574
  [c0e9dde0] [c00ab710] console_unlock+0x114/0x4f8
  [c0e9de40] [c00adc60] vprintk_emit+0x188/0x1c4
  --- interrupt: c0e9df00 at 0x400f330
      LR = init_stack+0x1f00/0x2000
  [c0e9de80] [c00ae3c4] printk+0xa8/0xcc (unreliable)
  [c0e9df20] [c0c27e44] early_irq_init+0x38/0x108
  [c0e9df50] [c0c15434] start_kernel+0x310/0x488
  [c0e9dff0] [00003484] 0x3484

With this patch the trace becomes:

  Call Trace:
  [c0e9dca0] [c01c42c0] print_address_description+0x64/0x2bc (unreliable)
  [c0e9dcd0] [c01c46a4] kasan_report+0xfc/0x180
  [c0e9dd10] [c0895150] memchr+0x24/0x74
  [c0e9dd30] [c00a9e58] msg_print_text+0x124/0x574
  [c0e9dde0] [c00ab730] console_unlock+0x114/0x4f8
  [c0e9de40] [c00adc80] vprintk_emit+0x188/0x1c4
  [c0e9de80] [c00ae3e4] printk+0xa8/0xcc
  [c0e9df20] [c0c27e44] early_irq_init+0x38/0x108
  [c0e9df50] [c0c15434] start_kernel+0x310/0x488
  [c0e9dff0] [00003484] 0x3484

Cc: stable@vger.kernel.org
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      40b97853
  19. 27 2月, 2019 1 次提交