linux-toradex.git/arch/s390, branch v4.2.4

s390/boot/decompression: disable floating point in decompressor

2015-10-22T21:49:19+00:00

commit adc0b7fbf6fe9967505c0254d9535ec7288186ae upstream.

my gcc 5.1 used an ldgr instruction with a register != 0,2,4,6 for
spilling/filling into a floating point register in our decompressor.

This will cause an AFP-register data exception as the decompressor
did not setup the additional floating point registers via cr0.
That causes a program check loop that looked like a hang with
one "Uncompressing Linux... " message (directly booted via kvm)
or a loop of "Uncompressing Linux... " messages (when booted via
zipl boot loader).

The offending code in my build was

   48e400:       e3 c0 af ff ff 71       lay     %r12,-1(%r10)
-->48e406:       b3 c1 00 1c             ldgr    %f1,%r12
   48e40a:       ec 6c 01 22 02 7f       clij    %r6,2,12,0x48e64e

but gcc could do spilling into an fpr at any function. We can
simply disable floating point support at that early stage.

Signed-off-by: Christian Borntraeger 
Acked-by: Heiko Carstens 
Signed-off-by: Greg Kroah-Hartman

s390/compat: correct uc_sigmask of the compat signal frame

2015-10-22T21:49:19+00:00

commit 8d4bd0ed0439dfc780aab801a085961925ed6838 upstream.

The uc_sigmask in the ucontext structure is an array of words to keep
the 64 signal bits (or 1024 if you ask glibc but the kernel sigset_t
only has 64 bits).

For 64 bit the sigset_t contains a single 8 byte word, but for 31 bit
there are two 4 byte words. The compat signal handler code uses a
simple copy of the 64 bit sigset_t to the 31 bit compat_sigset_t.
As s390 is a big-endian architecture this is incorrect, the two words
in the 31 bit sigset_t array need to be swapped.

Reported-by: Stefan Liebler 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

lib/decompressors: use real out buf size for gunzip with kernel

2015-09-29T17:33:37+00:00

commit 2d3862d26e67a59340ba1cf1748196c76c5787de upstream.

When loading x86 64bit kernel above 4GiB with patched grub2, got kernel
gunzip error.

| early console in decompress_kernel
| decompress_kernel:
|       input: [0x807f2143b4-0x807ff61aee]
|      output: [0x807cc00000-0x807f3ea29b] 0x027ea29c: output_len
| boot via startup_64
| KASLR using RDTSC...
|  new output: [0x46fe000000-0x470138cfff] 0x0338d000: output_run_size
|  decompress: [0x46fe000000-0x47007ea29b] <=== [0x807f2143b4-0x807ff61aee]
|
| Decompressing Linux... gz...
|
| uncompression error
|
| -- System halted

the new buffer is at 0x46fe000000ULL, decompressor_gzip is using
0xffffffb901ffffff as out_len.  gunzip in lib/zlib_inflate/inflate.c cap
that len to 0x01ffffff and decompress fails later.

We could hit this problem with crashkernel booting that uses kexec loading
kernel above 4GiB.

We have decompress_* support:
    1. inbuf[]/outbuf[] for kernel preboot.
    2. inbuf[]/flush() for initramfs
    3. fill()/flush() for initrd.
This bug only affect kernel preboot path that use outbuf[].

Add __decompress and take real out_buf_len for gunzip instead of guessing
wrong buf size.

Fixes: 1431574a1c4 (lib/decompressors: fix "no limit" output buffer length)
Signed-off-by: Yinghai Lu 
Cc: Alexandre Courbot 
Cc: Jon Medhurst 
Cc: Stephen Warren 
Cc: "H. Peter Anvin" 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

s390/setup: fix novx parameter

2015-09-21T17:10:43+00:00

commit 89b1145e93771d727645c96e323539c029b63f1c upstream.

The novx parameter disables the vector facility but the HWCAP_S390_VXRS
bit in the ELf hardware capabilies is always set if the machine has
the vector facility. If the user space program uses the "vx" string
in the features field of /proc/cpuinfo to utilize vector instruction
it will crash if the novx kernel paramter is set.

Convert setup_hwcaps to an arch_initcall and use MACHINE_HAS_VX to
decide if the HWCAPS_S390_VXRS bit needs to be set.

Reported-by: Ulrich Weigand 
Reviewed-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2015-08-05T15:50:38+00:00

Pull KVM fixes from Paolo Bonzini:
 "Just two very small & simple patches"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: MTRR: Use default type for non-MTRR-covered gfn before WARN_ON
  KVM: s390: Fix hang VCPU hang/loop regression

KVM: s390: Fix hang VCPU hang/loop regression

2015-07-30T11:11:13+00:00

commit 785dbef407d8 ("KVM: s390: optimize round trip time in request
handling") introduced a regression. This regression was seen with
CPU hotplug in the guest and switching between 1 or 2 CPUs. This will
set/reset the IBS control via synced request.

Whenever we make a synced request, we first set the vcpu->requests
bit and then block the vcpu. The handler, on the other hand, unblocks
itself, processes vcpu->requests (by clearing them) and unblocks itself
once again.

Now, if the requester sleeps between setting of vcpu->requests and
blocking, the handler will clear the vcpu->requests bit and try to
unblock itself (although no bit is set). When the requester wakes up,
it blocks the VCPU and we have a blocked VCPU without requests.

Solution is to always unset the block bit.

Signed-off-by: Christian Borntraeger 
Reviewed-by: David Hildenbrand 
Fixes: 785dbef407d8 ("KVM: s390: optimize round trip time in request handling")

s390/cachinfo: add missing facility check to init_cache_level()

2015-07-28T06:54:42+00:00

Stephen Powell reported the following crash on a z890 machine:

Kernel BUG at 00000000001219d0 [verbose debug info unavailable]
illegal operation: 0001 ilc:3 [#1] SMP
Krnl PSW : 0704e00180000000 00000000001219d0 (init_cache_level+0x38/0xe0)
	   R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 EA:3
Krnl Code: 00000000001219c2: a7840056		brc	8,121a6e
	   00000000001219c6: a7190000		lghi	%r1,0
	  #00000000001219ca: eb101000004c	ecag	%r1,%r0,0(%r1)
	  >00000000001219d0: a7390000		lghi	%r3,0
	   00000000001219d4: e310f0a00024	stg	%r1,160(%r15)
	   00000000001219da: a7080000		lhi	%r0,0
	   00000000001219de: a7b9f000		lghi	%r11,-4096
	   00000000001219e2: c0a0002899d9	larl	%r10,634d94
Call Trace:
 [<0000000000478ee2>] detect_cache_attributes+0x2a/0x2b8
 [<000000000097c9b0>] cacheinfo_sysfs_init+0x60/0xc8
 [<00000000001001c0>] do_one_initcall+0x98/0x1c8
 [<000000000094fdc2>] kernel_init_freeable+0x212/0x2d8
 [<000000000062352e>] kernel_init+0x26/0x118
 [<000000000062fd2e>] kernel_thread_starter+0x6/0xc

The illegal operation was executed because of a missing facility check,
which should have made sure that the ECAG execution would only be executed
on machines which have the general-instructions-extension facility
installed.

Reported-and-tested-by: Stephen Powell 
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/bpf: clear correct BPF accumulator register

2015-07-27T07:08:11+00:00

Currently we assumed the following BPF to eBPF register mapping:

 - BPF_REG_A -> BPF_REG_7
 - BPF_REG_X -> BPF_REG_8

Unfortunately this mapping is wrong. The correct mapping is:

 - BPF_REG_A -> BPF_REG_0
 - BPF_REG_X -> BPF_REG_7

So clear the correct registers and use the BPF_REG_A and BPF_REG_X
macros instead of BPF_REG_0/7.

Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend")
Cc: stable@vger.kernel.org # 4.0+
Signed-off-by: Michael Holzheu 
Signed-off-by: Martin Schwidefsky

s390: adapt entry.S to the move of thread_struct

2015-07-20T11:22:18+00:00

git commit 0c8c0f03e3a292e031596484275c14cf39c0ab7a
"x86/fpu, sched: Dynamically allocate 'struct fpu'"
moved the thread_struct to the end of the task_struct.

This causes some of the offsets used in entry.S to overflow their
instruction operand field. To fix this  use aghi to create a
dedicated pointer for the thread_struct.

Signed-off-by: Martin Schwidefsky

mm: clean up per architecture MM hook header files

2015-07-17T23:39:53+00:00

Commit 2ae416b142b6 ("mm: new mm hook framework") introduced an empty
header file (mm-arch-hooks.h) for every architecture, even those which
doesn't need to define mm hooks.

As suggested by Geert Uytterhoeven, this could be cleaned through the use
of a generic header file included via each per architecture
asm/include/Kbuild file.

The PowerPC architecture is not impacted here since this architecture has
to defined the arch_remap MM hook.

Signed-off-by: Laurent Dufour 
Suggested-by: Geert Uytterhoeven 
Acked-by: Geert Uytterhoeven 
Acked-by: Vineet Gupta 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds