linux-stable.git/arch/powerpc, branch v4.14.78

powerpc/lib/feature-fixups: use raw_patch_instruction()

2018-10-20T07:48:52+00:00

commit 8183d99f4a22c2abbc543847a588df3666ef0c0c upstream.

feature fixups need to use patch_instruction() early in the boot,
even before the code is relocated to its final address, requiring
patch_instruction() to use PTRRELOC() in order to address data.

But feature fixups applies on code before it is set to read only,
even for modules. Therefore, feature fixups can use
raw_patch_instruction() instead.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Reported-by: David Gounaris 
Tested-by: David Gounaris 
Signed-off-by: Greg Kroah-Hartman

powerpc/tm: Avoid possible userspace r1 corruption on reclaim

2018-10-20T07:48:52+00:00

[ Upstream commit 96dc89d526ef77604376f06220e3d2931a0bfd58 ]

Current we store the userspace r1 to PACATMSCRATCH before finally
saving it to the thread struct.

In theory an exception could be taken here (like a machine check or
SLB miss) that could write PACATMSCRATCH and hence corrupt the
userspace r1. The SLB fault currently doesn't touch PACATMSCRATCH, but
others do.

We've never actually seen this happen but it's theoretically
possible. Either way, the code is fragile as it is.

This patch saves r1 to the kernel stack (which can't fault) before we
turn MSR[RI] back on. PACATMSCRATCH is still used but only with
MSR[RI] off. We then copy r1 from the kernel stack to the thread
struct once we have MSR[RI] back on.

Suggested-by: Breno Leitao 
Signed-off-by: Michael Neuling 
Signed-off-by: Michael Ellerman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

powerpc/tm: Fix userspace r13 corruption

2018-10-20T07:48:52+00:00

[ Upstream commit cf13435b730a502e814c63c84d93db131e563f5f ]

When we treclaim we store the userspace checkpointed r13 to a scratch
SPR and then later save the scratch SPR to the user thread struct.

Unfortunately, this doesn't work as accessing the user thread struct
can take an SLB fault and the SLB fault handler will write the same
scratch SPRG that now contains the userspace r13.

To fix this, we store r13 to the kernel stack (which can't fault)
before we access the user thread struct.

Found by running P8 guest + powervm + disable_1tb_segments + TM. Seen
as a random userspace segfault with r13 looking like a kernel address.

Signed-off-by: Michael Neuling 
Reviewed-by: Breno Leitao 
Signed-off-by: Michael Ellerman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

mm: Preserve _PAGE_DEVMAP across mprotect() calls

2018-10-18T07:16:25+00:00

commit 4628a64591e6cee181237060961e98c615c33966 upstream.

Currently _PAGE_DEVMAP bit is not preserved in mprotect(2) calls. As a
result we will see warnings such as:

BUG: Bad page map in process JobWrk0013  pte:800001803875ea25 pmd:7624381067
addr:00007f0930720000 vm_flags:280000f9 anon_vma:          (null) mapping:ffff97f2384056f0 index:0
file:457-000000fe00000030-00000009-000000ca-00000001_2001.fileblock fault:xfs_filemap_fault [xfs] mmap:xfs_file_mmap [xfs] readpage:          (null)
CPU: 3 PID: 15848 Comm: JobWrk0013 Tainted: G        W          4.12.14-2.g7573215-default #1 SLE12-SP4 (unreleased)
Hardware name: Intel Corporation S2600WFD/S2600WFD, BIOS SE5C620.86B.01.00.0833.051120182255 05/11/2018
Call Trace:
 dump_stack+0x5a/0x75
 print_bad_pte+0x217/0x2c0
 ? enqueue_task_fair+0x76/0x9f0
 _vm_normal_page+0xe5/0x100
 zap_pte_range+0x148/0x740
 unmap_page_range+0x39a/0x4b0
 unmap_vmas+0x42/0x90
 unmap_region+0x99/0xf0
 ? vma_gap_callbacks_rotate+0x1a/0x20
 do_munmap+0x255/0x3a0
 vm_munmap+0x54/0x80
 SyS_munmap+0x1d/0x30
 do_syscall_64+0x74/0x150
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
...

when mprotect(2) gets used on DAX mappings. Also there is a wide variety
of other failures that can result from the missing _PAGE_DEVMAP flag
when the area gets used by get_user_pages() later.

Fix the problem by including _PAGE_DEVMAP in a set of flags that get
preserved by mprotect(2).

Fixes: 69660fd797c3 ("x86, mm: introduce _PAGE_DEVMAP")
Fixes: ebd31197931d ("powerpc/mm: Add devmap support for ppc64")
Cc: 
Signed-off-by: Jan Kara 
Acked-by: Michal Hocko 
Reviewed-by: Johannes Thumshirn 
Signed-off-by: Dan Williams 
Signed-off-by: Greg Kroah-Hartman

powerpc/lib: fix book3s/32 boot failure due to code patching

2018-10-13T07:27:28+00:00

commit b45ba4a51cde29b2939365ef0c07ad34c8321789 upstream.

Commit 51c3c62b58b3 ("powerpc: Avoid code patching freed init
sections") accesses 'init_mem_is_free' flag too early, before the
kernel is relocated. This provokes early boot failure (before the
console is active).

As it is not necessary to do this verification that early, this
patch moves the test into patch_instruction() instead of
__patch_instruction().

This modification also has the advantage of avoiding unnecessary
remappings.

Fixes: 51c3c62b58b3 ("powerpc: Avoid code patching freed init sections")
Cc: stable@vger.kernel.org # 4.13+
Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc: Avoid code patching freed init sections

2018-10-13T07:27:28+00:00

commit 51c3c62b58b357e8d35e4cc32f7b4ec907426fe3 upstream.

This stops us from doing code patching in init sections after they've
been freed.

In this chain:
  kvm_guest_init() ->
    kvm_use_magic_page() ->
      fault_in_pages_readable() ->
	 __get_user() ->
	   __get_user_nocheck() ->
	     barrier_nospec();

We have a code patching location at barrier_nospec() and
kvm_guest_init() is an init function. This whole chain gets inlined,
so when we free the init section (hence kvm_guest_init()), this code
goes away and hence should no longer be patched.

We seen this as userspace memory corruption when using a memory
checker while doing partition migration testing on powervm (this
starts the code patching post migration via
/sys/kernel/mobility/migration). In theory, it could also happen when
using /sys/kernel/debug/powerpc/barrier_nospec.

Cc: stable@vger.kernel.org # 4.13+
Signed-off-by: Michael Neuling 
Reviewed-by: Nicholas Piggin 
Reviewed-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/lib/code-patching: refactor patch_instruction()

2018-10-13T07:27:28+00:00

commit 8cf4c05712f04a405f0dacebcca8f042b391694a upstream.

patch_instruction() uses almost the same sequence as
__patch_instruction()

This patch refactor it so that patch_instruction() uses
__patch_instruction() instead of duplicating code.

Signed-off-by: Christophe Leroy 
Acked-by: Balbir Singh 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S HV: Don't truncate HPTE index in xlate function

2018-10-10T06:54:19+00:00

[ Upstream commit 46dec40fb741f00f1864580130779aeeaf24fb3d ]

This fixes a bug which causes guest virtual addresses to get translated
to guest real addresses incorrectly when the guest is using the HPT MMU
and has more than 256GB of RAM, or more specifically has a HPT larger
than 2GB.  This has showed up in testing as a failure of the host to
emulate doorbell instructions correctly on POWER9 for HPT guests with
more than 256GB of RAM.

The bug is that the HPTE index in kvmppc_mmu_book3s_64_hv_xlate()
is stored as an int, and in forming the HPTE address, the index gets
shifted left 4 bits as an int before being signed-extended to 64 bits.
The simple fix is to make the variable a long int, matching the
return type of kvmppc_hv_find_lock_hpte(), which is what calculates
the index.

Fixes: 697d3899dcb4 ("KVM: PPC: Implement MMIO emulation support for Book3S HV guests")
Signed-off-by: Paul Mackerras 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

powerpc/powernv/ioda2: Reduce upper limit for DMA window size

2018-10-04T00:00:49+00:00

[ Upstream commit d3d4ffaae439981e1e441ebb125aa3588627c5d8 ]

We use PHB in mode1 which uses bit 59 to select a correct DMA window.
However there is mode2 which uses bits 59:55 and allows up to 32 DMA
windows per a PE.

Even though documentation does not clearly specify that, it seems that
the actual hardware does not support bits 59:55 even in mode1, in other
words we can create a window as big as 1<<58 but DMA simply won't work.

This reduces the upper limit from 59 to 55 bits to let the userspace know
about the hardware limits.

Fixes: 7aafac11e3 "powerpc/powernv/ioda2: Gracefully fail if too many TCE levels requested"
Signed-off-by: Alexey Kardashevskiy 
Signed-off-by: Michael Ellerman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

powerpc/kdump: Handle crashkernel memory reservation failure

2018-10-04T00:00:48+00:00

[ Upstream commit 8950329c4a64c6d3ca0bc34711a1afbd9ce05657 ]

Memory reservation for crashkernel could fail if there are holes around
kdump kernel offset (128M). Fail gracefully in such cases and print an
error message.

Signed-off-by: Hari Bathini 
Tested-by: David Gibson 
Reviewed-by: Dave Young 
Signed-off-by: Michael Ellerman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman