linux-stable.git/arch/s390/kernel/module.c, branch linux-4.4.y

s390: correct module section names for expoline code revert

2018-04-29T05:50:04+00:00

[ Upstream commit 6cf09958f32b9667bb3ebadf74367c791112771b ]

The main linker script vmlinux.lds.S for the kernel image merges
the expoline code patch tables into two section ".nospec_call_table"
and ".nospec_return_table". This is *not* done for the modules,
there the sections retain their original names as generated by gcc:
".s390_indirect_call", ".s390_return_mem" and ".s390_return_reg".

The module_finalize code has to check for the compiler generated
section names, otherwise no code patching is done. This slows down
the module code in case of "spectre_v2=off".

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

s390: add automatic detection of the spectre defense

2018-04-29T05:50:04+00:00

[ Upstream commit 6e179d64126b909f0b288fa63cdbf07c531e9b1d ]

Automatically decide between nobp vs. expolines if the spectre_v2=auto
kernel parameter is specified or CONFIG_EXPOLINE_AUTO=y is set.

The decision made at boot time due to CONFIG_EXPOLINE_AUTO=y being set
can be overruled with the nobp, nospec and spectre_v2 kernel parameters.

Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

s390: introduce execute-trampolines for branches

2018-04-29T05:50:03+00:00

[ Upstream commit f19fbd5ed642dc31c809596412dab1ed56f2f156 ]

Add CONFIG_EXPOLINE to enable the use of the new -mindirect-branch= and
-mfunction_return= compiler options to create a kernel fortified against
the specte v2 attack.

With CONFIG_EXPOLINE=y all indirect branches will be issued with an
execute type instruction. For z10 or newer the EXRL instruction will
be used, for older machines the EX instruction. The typical indirect
call

	basr	%r14,%r1

is replaced with a PC relative call to a new thunk

	brasl	%r14,__s390x_indirect_jump_r1

The thunk contains the EXRL/EX instruction to the indirect branch

__s390x_indirect_jump_r1:
	exrl	0,0f
	j	.
0:	br	%r1

The detour via the execute type instruction has a performance impact.
To get rid of the detour the new kernel parameter "nospectre_v2" and
"spectre_v2=[on,off,auto]" can be used. If the parameter is specified
the kernel and module code will be patched at runtime.

Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

s390: enable CPU alternatives unconditionally

2018-04-29T05:50:02+00:00

[ Upstream commit 049a2c2d486e8cc82c5cd79fa479c5b105b109e9 ]

Remove the CPU_ALTERNATIVES config option and enable the code
unconditionally. The config option was only added to avoid a conflict
with the named saved segment support. Since that code is gone there is
no reason to keep the CPU_ALTERNATIVES config option.

Just enable it unconditionally to also reduce the number of config
options and make it less likely that something breaks.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

s390: introduce CPU alternatives

2018-04-29T05:50:02+00:00

[ Upstream commit 686140a1a9c41d85a4212a1c26d671139b76404b ]

Implement CPU alternatives, which allows to optionally patch newer
instructions at runtime, based on CPU facilities availability.

A new kernel boot parameter "noaltinstr" disables patching.

Current implementation is derived from x86 alternatives. Although
ideal instructions padding (when altinstr is longer then oldinstr)
is added at compile time, and no oldinstr nops optimization has to be
done at runtime. Also couple of compile time sanity checks are done:
1. oldinstr and altinstr must be <= 254 bytes long,
2. oldinstr and altinstr must not have an odd length.

alternative(oldinstr, altinstr, facility);
alternative_2(oldinstr, altinstr1, facility1, altinstr2, facility2);

Both compile time and runtime padding consists of either 6/4/2 bytes nop
or a jump (brcl) + 2 bytes nop filler if padding is longer then 6 bytes.

.altinstructions and .altinstr_replacement sections are part of
__init_begin : __init_end region and are freed after initialization.

Signed-off-by: Vasily Gorbik 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Greg Kroah-Hartman

s390: remove 31 bit support

2015-03-25T10:49:33+00:00

Remove the 31 bit support in order to reduce maintenance cost and
effectively remove dead code. Since a couple of years there is no
distribution left that comes with a 31 bit kernel.

The 31 bit kernel also has been broken since more than a year before
anybody noticed. In addition I added a removal warning to the kernel
shown at ipl for 5 minutes: a960062e5826 ("s390: add 31 bit warning
message") which let everybody know about the plan to remove 31 bit
code. We didn't get any response.

Given that the last 31 bit only machine was introduced in 1999 let's
remove the code.
Anybody with 31 bit user space code can still use the compat mode.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/jump label: add missing jump_label_apply_nops() call

2015-02-26T08:24:45+00:00

When modules are loaded we want to transform the compile time generated
nops into runtime generated nops. Otherwise the jump label sanity check
will detect invalid code when trying to patch code.

Fixes this crash:

Jump label code mismatch at __rds_conn_create+0x3c/0x720
Found:    c0 04 00 00 00 01
Expected: c0 04 00 00 00 00
Kernel panic - not syncing: Corrupted kernel text
CPU: 0 PID: 10 Comm: migration/0 Not tainted 3.19.0-01935-g006610f #14
Call Trace:
<0000000000113260> show_trace+0xf8/0x158)
<000000000011332a> show_stack+0x6a/0xe8
<000000000069fd64> dump_stack+0x7c/0xd8
<0000000000698d54> panic+0xe4/0x288
<00000000006984c6> jump_label_bug.isra.2+0xbe/0xc001
<000000000011200c> __jump_label_transform+0x94/0xc8

Reported-by: Sebastian Ott 
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

mm: vmalloc: pass additional vm_flags to __vmalloc_node_range()

2015-02-14T05:21:42+00:00

For instrumenting global variables KASan will shadow memory backing memory
for modules.  So on module loading we will need to allocate memory for
shadow and map it at address in shadow that corresponds to the address
allocated in module_alloc().

__vmalloc_node_range() could be used for this purpose, except it puts a
guard hole after allocated area.  Guard hole in shadow memory should be a
problem because at some future point we might need to have a shadow memory
at address occupied by guard hole.  So we could fail to allocate shadow
for module_alloc().

Now we have VM_NO_GUARD flag disabling guard page, so we need to pass into
__vmalloc_node_range().  Add new parameter 'vm_flags' to
__vmalloc_node_range() function.

Signed-off-by: Andrey Ryabinin 
Cc: Dmitry Vyukov 
Cc: Konstantin Serebryany 
Cc: Dmitry Chernenkov 
Signed-off-by: Andrey Konovalov 
Cc: Yuri Gribov 
Cc: Konstantin Khlebnikov 
Cc: Sasha Levin 
Cc: Christoph Lameter 
Cc: Joonsoo Kim 
Cc: Dave Hansen 
Cc: Andi Kleen 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

module_arch_freeing_init(): new hook for archs before module->module_init freed.

2015-01-20T01:08:32+00:00

Archs have been abusing module_free() to clean up their arch-specific
allocations.  Since module_free() is also (ab)used by BPF and trace code,
let's keep it to simple allocations, and provide a hook called before
that.

This means that avr32, ia64, parisc and s390 no longer need to implement
their own module_free() at all.  avr32 doesn't need module_finalize()
either.

Signed-off-by: Rusty Russell 
Cc: Chris Metcalf 
Cc: Haavard Skinnemoen 
Cc: Hans-Christian Egtvedt 
Cc: Tony Luck 
Cc: Fenghua Yu 
Cc: "James E.J. Bottomley" 
Cc: Helge Deller 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: linux-kernel@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linux-s390@vger.kernel.org

mm/arch: use NUMA_NO_NODE

2013-11-13T03:09:05+00:00

Use more appropriate NUMA_NO_NODE instead of -1 in all archs' module_alloc()

Signed-off-by: Jianguo Wu 
Acked-by: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds