linux-stable.git/arch/powerpc/kernel, branch v4.4.166

powerpc/tm: Avoid possible userspace r1 corruption on reclaim

2018-10-20T07:52:38+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

2018-10-20T07:52:38+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

powerpc/fadump: Return error when fadump registration fails

2018-10-13T07:11:33+00:00

commit 98b8cd7f75643e0a442d7a4c1cef2c9d53b7e92b upstream.

 - log an error message when registration fails and no error code listed
   in the switch is returned
 - translate the hv error code to posix error code and return it from
   fw_register
 - return the posix error code from fw_register to the process writing
   to sysfs
 - return EEXIST on re-registration
 - return success on deregistration when fadump is not registered
 - return ENODEV when no memory is reserved for fadump

Signed-off-by: Michal Suchanek 
Tested-by: Hari Bathini 
[mpe: Use pr_err() to shrink the error print]
Signed-off-by: Michael Ellerman 
Cc: Kleber Sacilotto de Souza 
Signed-off-by: Greg Kroah-Hartman

powerpc/kdump: Handle crashkernel memory reservation failure

2018-10-10T06:52:04+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

powerpc/fadump: handle crash memory ranges array index overflow

2018-09-09T18:04:32+00:00

commit 1bd6a1c4b80a28d975287630644e6b47d0f977a5 upstream.

Crash memory ranges is an array of memory ranges of the crashing kernel
to be exported as a dump via /proc/vmcore file. The size of the array
is set based on INIT_MEMBLOCK_REGIONS, which works alright in most cases
where memblock memory regions count is less than INIT_MEMBLOCK_REGIONS
value. But this count can grow beyond INIT_MEMBLOCK_REGIONS value since
commit 142b45a72e22 ("memblock: Add array resizing support").

On large memory systems with a few DLPAR operations, the memblock memory
regions count could be larger than INIT_MEMBLOCK_REGIONS value. On such
systems, registering fadump results in crash or other system failures
like below:

  task: c00007f39a290010 ti: c00000000b738000 task.ti: c00000000b738000
  NIP: c000000000047df4 LR: c0000000000f9e58 CTR: c00000000010f180
  REGS: c00000000b73b570 TRAP: 0300   Tainted: G          L   X  (4.4.140+)
  MSR: 8000000000009033   CR: 22004484  XER: 20000000
  CFAR: c000000000008500 DAR: 000007a450000000 DSISR: 40000000 SOFTE: 0
  ...
  NIP [c000000000047df4] smp_send_reschedule+0x24/0x80
  LR [c0000000000f9e58] resched_curr+0x138/0x160
  Call Trace:
    resched_curr+0x138/0x160 (unreliable)
    check_preempt_curr+0xc8/0xf0
    ttwu_do_wakeup+0x38/0x150
    try_to_wake_up+0x224/0x4d0
    __wake_up_common+0x94/0x100
    ep_poll_callback+0xac/0x1c0
    __wake_up_common+0x94/0x100
    __wake_up_sync_key+0x70/0xa0
    sock_def_readable+0x58/0xa0
    unix_stream_sendmsg+0x2dc/0x4c0
    sock_sendmsg+0x68/0xa0
    ___sys_sendmsg+0x2cc/0x2e0
    __sys_sendmsg+0x5c/0xc0
    SyS_socketcall+0x36c/0x3f0
    system_call+0x3c/0x100

as array index overflow is not checked for while setting up crash memory
ranges causing memory corruption. To resolve this issue, dynamically
allocate memory for crash memory ranges and resize it incrementally,
in units of pagesize, on hitting array size limit.

Fixes: 2df173d9e85d ("fadump: Initialize elfcore header and add PT_LOAD program headers.")
Cc: stable@vger.kernel.org # v3.4+
Signed-off-by: Hari Bathini 
Reviewed-by: Mahesh Salgaonkar 
[mpe: Just use PAGE_SIZE directly, fixup variable placement]
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/8xx: fix invalid register expression in head_8xx.S

2018-08-06T14:24:34+00:00

[ Upstream commit e4ccb1dae6bdef228d729c076c38161ef6e7ca34 ]

New binutils generate the following warning

  AS      arch/powerpc/kernel/head_8xx.o
arch/powerpc/kernel/head_8xx.S: Assembler messages:
arch/powerpc/kernel/head_8xx.S:916: Warning: invalid register expression

This patch fixes it.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

powerpc/32: Add a missing include header

2018-08-06T14:24:34+00:00

[ Upstream commit c89ca593220931c150cffda24b4d4ccf82f13fc8 ]

The header file  was missing from the includes. Fix the
following warning, treated as error with W=1:

  arch/powerpc/kernel/pci_32.c:286:6: error: no previous prototype for ‘sys_pciconfig_iobase’ [-Werror=missing-prototypes]

Signed-off-by: Mathieu Malaterre 
Signed-off-by: Michael Ellerman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

powerpc/fadump: Unregister fadump on kexec down path.

2018-07-03T09:21:29+00:00

commit 722cde76d68e8cc4f3de42e71c82fd40dea4f7b9 upstream.

Unregister fadump on kexec down path otherwise the fadump registration
in new kexec-ed kernel complains that fadump is already registered.
This makes new kernel to continue using fadump registered by previous
kernel which may lead to invalid vmcore generation. Hence this patch
fixes this issue by un-registering fadump in fadump_cleanup() which is
called during kexec path so that new kernel can register fadump with
new valid values.

Fixes: b500afff11f6 ("fadump: Invalidate registration and release reserved memory for general use.")
Cc: stable@vger.kernel.org # v3.4+
Signed-off-by: Mahesh Salgaonkar 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/ptrace: Fix enforcement of DAWR constraints

2018-07-03T09:21:29+00:00

commit cd6ef7eebf171bfcba7dc2df719c2a4958775040 upstream.

Back when we first introduced the DAWR, in commit 4ae7ebe9522a
("powerpc: Change hardware breakpoint to allow longer ranges"), we
screwed up the constraint making it a 1024 byte boundary rather than a
512. This makes the check overly permissive. Fortunately GDB is the
only real user and it always did they right thing, so we never
noticed.

This fixes the constraint to 512 bytes.

Fixes: 4ae7ebe9522a ("powerpc: Change hardware breakpoint to allow longer ranges")
Cc: stable@vger.kernel.org # v3.9+
Signed-off-by: Michael Neuling 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/ptrace: Fix setting 512B aligned breakpoints with PTRACE_SET_DEBUGREG

2018-07-03T09:21:28+00:00

commit 4f7c06e26ec9cf7fe9f0c54dc90079b6a4f4b2c3 upstream.

In commit e2a800beaca1 ("powerpc/hw_brk: Fix off by one error when
validating DAWR region end") we fixed setting the DAWR end point to
its max value via PPC_PTRACE_SETHWDEBUG. Unfortunately we broke
PTRACE_SET_DEBUGREG when setting a 512 byte aligned breakpoint.

PTRACE_SET_DEBUGREG currently sets the length of the breakpoint to
zero (memset() in hw_breakpoint_init()). This worked with
arch_validate_hwbkpt_settings() before the above patch was applied but
is now broken if the breakpoint is 512byte aligned.

This sets the length of the breakpoint to 8 bytes when using
PTRACE_SET_DEBUGREG.

Fixes: e2a800beaca1 ("powerpc/hw_brk: Fix off by one error when validating DAWR region end")
Cc: stable@vger.kernel.org # v3.11+
Signed-off-by: Michael Neuling 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman