Commit Graph

5478 Commits

Author SHA1 Message Date
Martin Schwidefsky
c1a35f5ddf s390: use expoline thunks in the BPF JIT
[ Upstream commit de5cb6eb51 ]

The BPF JIT need safe guarding against spectre v2 in the sk_load_xxx
assembler stubs and the indirect branches generated by the JIT itself
need to be converted to expolines.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-25 16:17:33 +02:00
Martin Schwidefsky
457b944b61 s390: extend expoline to BC instructions
[ Upstream commit 6deaa3bbca ]

The BPF JIT uses a 'b <disp>(%r<x>)' instruction in the definition
of the sk_load_word and sk_load_half functions.

Add support for branch-on-condition instructions contained in the
thunk code of an expoline.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-25 16:17:33 +02:00
Martin Schwidefsky
a206c82f9b s390: move spectre sysfs attribute code
[ Upstream commit 4253b0e062 ]

The nospec-branch.c file is compiled without the gcc options to
generate expoline thunks. The return branch of the sysfs show
functions cpu_show_spectre_v1 and cpu_show_spectre_v2 is an indirect
branch as well. These need to be compiled with expolines.

Move the sysfs functions for spectre reporting to a separate file
and loose an '.' for one of the messages.

Cc: stable@vger.kernel.org # 4.16
Fixes: d424986f1d ("s390: add sysfs attributes for spectre")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-25 16:17:33 +02:00
Martin Schwidefsky
2a146a9b32 s390/kernel: use expoline for indirect branches
[ Upstream commit c50c84c3ac ]

The assember code in arch/s390/kernel uses a few more indirect branches
which need to be done with execute trampolines for CONFIG_EXPOLINE=y.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-25 16:17:32 +02:00
Martin Schwidefsky
f1bd3b9960 s390/ftrace: use expoline for indirect branches
[ Upstream commit 23a4d7fd34 ]

The return from the ftrace_stub, _mcount, ftrace_caller and
return_to_handler functions is done with "br %r14" and "br %r1".
These are indirect branches as well and need to use execute
trampolines for CONFIG_EXPOLINE=y.

The ftrace_caller function is a special case as it returns to the
start of a function and may only use %r0 and %r1. For a pre z10
machine the standard execute trampoline uses a LARL + EX to do
this, but this requires *two* registers in the range %r1..%r15.
To get around this the 'br %r1' located in the lowcore is used,
then the EX instruction does not need an address register.
But the lowcore trick may only be used for pre z14 machines,
with noexec=on the mapping for the first page may not contain
instructions. The solution for that is an ALTERNATIVE in the
expoline THUNK generated by 'GEN_BR_THUNK %r1' to switch to
EXRL, this relies on the fact that a machine that supports
noexec=on has EXRL as well.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-25 16:17:32 +02:00
Martin Schwidefsky
0d201ff077 s390/lib: use expoline for indirect branches
[ Upstream commit 97489e0663 ]

The return from the memmove, memset, memcpy, __memset16, __memset32 and
__memset64 functions are done with "br %r14". These are indirect branches
as well and need to use execute trampolines for CONFIG_EXPOLINE=y.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-25 16:17:32 +02:00
Martin Schwidefsky
d7aa3f13e1 s390/crc32-vx: use expoline for indirect branches
[ Upstream commit 467a3bf219 ]

The return from the crc32_le_vgfm_16/crc32c_le_vgfm_16 and the
crc32_be_vgfm_16 functions are done with "br %r14". These are indirect
branches as well and need to use execute trampolines for CONFIG_EXPOLINE=y.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-25 16:17:32 +02:00
Martin Schwidefsky
e3ad546e60 s390: move expoline assembler macros to a header
[ Upstream commit 6dd85fbb87 ]

To be able to use the expoline branches in different assembler
files move the associated macros from entry.S to a new header
nospec-insn.h.

While we are at it make the macros a bit nicer to use.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-25 16:17:31 +02:00
Martin Schwidefsky
9a38169fb6 s390: add assembler macros for CPU alternatives
[ Upstream commit fba9eb7946 ]

Add a header with macros usable in assembler files to emit alternative
code sequences. It works analog to the alternatives for inline assmeblies
in C files, with the same restrictions and capabilities.
The syntax is

     ALTERNATIVE "<default instructions sequence>", \
		 "<alternative instructions sequence>", \
		 "<features-bit>"
and

     ALTERNATIVE_2 "<default instructions sequence>", \
		   "<alternative instructions sqeuence #1>", \
		   "<feature-bit #1>",
		   "<alternative instructions sqeuence #2>", \
		   "<feature-bit #2>"

Reviewed-by: Vasily Gorbik <gor@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-25 16:17:31 +02:00
Martin Schwidefsky
a6565fdd90 s390: remove indirect branch from do_softirq_own_stack
commit 9f18fff63c upstream.

The inline assembly to call __do_softirq on the irq stack uses
an indirect branch. This can be replaced with a normal relative
branch.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-22 18:53:59 +02:00
Hendrik Brueckner
56130d9322 s390/cpum_sf: ensure sample frequency of perf event attributes is non-zero
commit 4bbaf2584b upstream.

Correct a trinity finding for the perf_event_open() system call with
a perf event attribute structure that uses a frequency but has the
sampling frequency set to zero.  This causes a FP divide exception during
the sample rate initialization for the hardware sampling facility.

Fixes: 8c069ff4bd ("s390/perf: add support for the CPU-Measurement Sampling Facility")
Cc: stable@vger.kernel.org # 3.14+
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-22 18:53:59 +02:00
Heiko Carstens
c371fe0190 s390/uprobes: implement arch_uretprobe_is_alive()
commit 783c3b53b9 upstream.

Implement s390 specific arch_uretprobe_is_alive() to avoid SIGSEGVs
observed with uretprobes in combination with setjmp/longjmp.

See commit 2dea1d9c38 ("powerpc/uprobes: Implement
arch_uretprobe_is_alive()") for more details.

With this implemented all test cases referenced in the above commit
pass.

Reported-by: Ziqian SUN <zsun@redhat.com>
Cc: <stable@vger.kernel.org> # v4.3+
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:18 +02:00
Martin Schwidefsky
5787b55b50 s390: correct module section names for expoline code revert
[ Upstream commit 6cf09958f3 ]

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 <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:16 +02:00
Martin Schwidefsky
f836b34fb0 s390: correct nospec auto detection init order
[ Upstream commit 6a3d1e81a4 ]

With CONFIG_EXPOLINE_AUTO=y the call of spectre_v2_auto_early() via
early_initcall is done *after* the early_param functions. This
overwrites any settings done with the nobp/no_spectre_v2/spectre_v2
parameters. The code patching for the kernel is done after the
evaluation of the early parameters but before the early_initcall
is done. The end result is a kernel image that is patched correctly
but the kernel modules are not.

Make sure that the nospec auto detection function is called before the
early parameters are evaluated and before the code patching is done.

Fixes: 6e179d6412 ("s390: add automatic detection of the spectre defense")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:16 +02:00
Martin Schwidefsky
fce1bf054f s390: add sysfs attributes for spectre
[ Upstream commit d424986f1d ]

Set CONFIG_GENERIC_CPU_VULNERABILITIES and provide the two functions
cpu_show_spectre_v1 and cpu_show_spectre_v2 to report the spectre
mitigations.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:15 +02:00
Martin Schwidefsky
68cb884e12 s390: report spectre mitigation via syslog
[ Upstream commit bc03559971 ]

Add a boot message if either of the spectre defenses is active.
The message is
    "Spectre V2 mitigation: execute trampolines."
or  "Spectre V2 mitigation: limited branch prediction."

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:15 +02:00
Martin Schwidefsky
719b84c9ae s390: add automatic detection of the spectre defense
[ Upstream commit 6e179d6412 ]

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 <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:15 +02:00
Martin Schwidefsky
ea1bbd53f0 s390: move nobp parameter functions to nospec-branch.c
[ Upstream commit b2e2f43a01 ]

Keep the code for the nobp parameter handling with the code for
expolines. Both are related to the spectre v2 mitigation.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:15 +02:00
Christian Borntraeger
6cdc4b21d2 s390/entry.S: fix spurious zeroing of r0
[ Upstream commit d3f468963c ]

when a system call is interrupted we might call the critical section
cleanup handler that re-does some of the operations. When we are between
.Lsysc_vtime and .Lsysc_do_svc we might also redo the saving of the
problem state registers r0-r7:

.Lcleanup_system_call:
[...]
0:      # update accounting time stamp
        mvc     __LC_LAST_UPDATE_TIMER(8),__LC_SYNC_ENTER_TIMER
        # set up saved register r11
        lg      %r15,__LC_KERNEL_STACK
        la      %r9,STACK_FRAME_OVERHEAD(%r15)
        stg     %r9,24(%r11)            # r11 pt_regs pointer
        # fill pt_regs
        mvc     __PT_R8(64,%r9),__LC_SAVE_AREA_SYNC
--->    stmg    %r0,%r7,__PT_R0(%r9)

The problem is now, that we might have already zeroed out r0.
The fix is to move the zeroing of r0 after sysc_do_svc.

Reported-by: Farhan Ali <alifm@linux.vnet.ibm.com>
Fixes: 7041d28115 ("s390: scrub registers on kernel entry and KVM exit")
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:15 +02:00
Martin Schwidefsky
74a93ae5c3 s390: do not bypass BPENTER for interrupt system calls
[ Upstream commit d5feec04fe ]

The system call path can be interrupted before the switch back to the
standard branch prediction with BPENTER has been done. The critical
section cleanup code skips forward to .Lsysc_do_svc and bypasses the
BPENTER. In this case the kernel and all subsequent code will run with
the limited branch prediction.

Fixes: eacf67eb9b32 ("s390: run user space and KVM guests with modified branch prediction")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:15 +02:00
Eugeniu Rosca
6288e169a2 s390: Replace IS_ENABLED(EXPOLINE_*) with IS_ENABLED(CONFIG_EXPOLINE_*)
[ Upstream commit 2cb370d615 ]

I've accidentally stumbled upon the IS_ENABLED(EXPOLINE_*) lines, which
obviously always evaluate to false. Fix this.

Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:15 +02:00
Christian Borntraeger
1d966a6ade KVM: s390: force bp isolation for VSIE
[ Upstream commit f315104ad8 ]

If the guest runs with bp isolation when doing a SIE instruction,
we must also run the nested guest with bp isolation when emulating
that SIE instruction.
This is done by activating BPBC in the lpar, which acts as an override
for lower level guests.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:15 +02:00
Martin Schwidefsky
b609eb65f3 s390: introduce execute-trampolines for branches
[ Upstream commit f19fbd5ed6 ]

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 <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:15 +02:00
Martin Schwidefsky
0bd4c47c20 s390: run user space and KVM guests with modified branch prediction
[ Upstream commit 6b73044b2b ]

Define TIF_ISOLATE_BP and TIF_ISOLATE_BP_GUEST and add the necessary
plumbing in entry.S to be able to run user space and KVM guests with
limited branch prediction.

To switch a user space process to limited branch prediction the
s390_isolate_bp() function has to be call, and to run a vCPU of a KVM
guest associated with the current task with limited branch prediction
call s390_isolate_bp_guest().

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:14 +02:00
Martin Schwidefsky
43cccd87c1 s390: add options to change branch prediction behaviour for the kernel
[ Upstream commit d768bd892f ]

Add the PPA instruction to the system entry and exit path to switch
the kernel to a different branch prediction behaviour. The instructions
are added via CPU alternatives and can be disabled with the "nospec"
or the "nobp=0" kernel parameter. If the default behaviour selected
with CONFIG_KERNEL_NOBP is set to "n" then the "nobp=1" parameter can be
used to enable the changed kernel branch prediction.

Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:14 +02:00
Martin Schwidefsky
c257f81b6d s390/alternative: use a copy of the facility bit mask
[ Upstream commit cf14899846 ]

To be able to switch off specific CPU alternatives with kernel parameters
make a copy of the facility bit mask provided by STFLE and use the copy
for the decision to apply an alternative.

Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:14 +02:00
Martin Schwidefsky
2ae89b86a7 s390: add optimized array_index_mask_nospec
[ Upstream commit e2dd833389 ]

Add an optimized version of the array_index_mask_nospec function for
s390 based on a compare and a subtract with borrow.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:14 +02:00
Martin Schwidefsky
2ae8b68382 s390: scrub registers on kernel entry and KVM exit
[ Upstream commit 7041d28115 ]

Clear all user space registers on entry to the kernel and all KVM guest
registers on KVM guest exit if the register does not contain either a
parameter or a result value.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:14 +02:00
Christian Borntraeger
ea5566fecd KVM: s390: wire up bpb feature
[ Upstream commit 35b3fde620 ]

The new firmware interfaces for branch prediction behaviour changes
are transparently available for the guest. Nevertheless, there is
new state attached that should be migrated and properly resetted.
Provide a mechanism for handling reset, migration and VSIE.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
[Changed capability number to 152. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:14 +02:00
Heiko Carstens
37e7974712 s390: enable CPU alternatives unconditionally
[ Upstream commit 049a2c2d48 ]

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 <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:14 +02:00
Vasily Gorbik
b44533a06f s390: introduce CPU alternatives
[ Upstream commit 686140a1a9 ]

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 <gor@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-29 11:33:14 +02:00
Sebastian Ott
2cd5100363 s390/eadm: fix CONFIG_BLOCK include dependency
[ Upstream commit 366b77ae43 ]

Commit 2a842acab1 ("block: introduce new block status code type")
added blk_status_t usage to the eadm subchannel driver. However
blk_status_t is unknown when included via <linux/blkdev.h> for CONFIG_BLOCK=n.

Only include <linux/blk_types.h> since this is the only dependency eadm has.

This fixes build failures like below:
In file included from drivers/s390/cio/eadm_sch.c:24:0:
./arch/s390/include/asm/eadm.h:111:4: error: unknown type name 'blk_status_t'; did you mean 'si_status'?
    blk_status_t error);

Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-26 11:02:16 +02:00
David Hildenbrand
a42ebbdae0 KVM: s390: vsie: use READ_ONCE to access some SCB fields
[ Upstream commit b3ecd4aa86 ]

Another VCPU might try to modify the SCB while we are creating the
shadow SCB. In general this is no problem - unless the compiler decides
to not load values once, but e.g. twice.

For us, this is only relevant when checking/working with such values.
E.g. the prefix value, the mso, state of transactional execution and
addresses of satellite blocks.

E.g. if we blindly forward values (e.g. general purpose registers or
execution controls after masking), we don't care.

Leaving unpin_blocks() untouched for now, will handle it separately.

The worst thing right now that I can see would be a missed prefix
un/remap (mso, prefix, tx) or using wrong guest addresses. Nothing
critical, but let's try to avoid unpredictable behavior.

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180116171526.12343-2-david@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-26 11:02:11 +02:00
Christian Borntraeger
80bd91ab9a KVM: s390: use created_vcpus in more places
[ Upstream commit 241e3ec0fa ]

commit a03825bbd0 ("KVM: s390: use kvm->created_vcpus") introduced
kvm->created_vcpus to avoid races with the existing kvm->online_vcpus
scheme. One place was "forgotten" and one new place was "added".
Let's fix those.

Reported-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Fixes: 4e0b1ab72b ("KVM: s390: gs support for kvm guests")
Fixes: a03825bbd0 ("KVM: s390: use kvm->created_vcpus")
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-26 11:02:04 +02:00
Al Viro
bb5def77d0 hypfs_kill_super(): deal with failed allocations
commit a24cd49073 upstream.

hypfs_fill_super() might fail to allocate sbi; hypfs_kill_super()
should not oops on that.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-24 09:36:38 +02:00
Vasily Gorbik
3da5723b4f s390/ipl: ensure loadparm valid flag is set
commit 15deb080a6 upstream.

When loadparm is set in reipl parm block, the kernel should also set
DIAG308_FLAGS_LP_VALID flag.

This fixes loadparm ignoring during z/VM fcp -> ccw reipl and kvm direct
boot -> ccw reipl.

Cc: <stable@vger.kernel.org>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-19 08:56:19 +02:00
David Hildenbrand
3da2a62a61 KVM: s390: fix memory overwrites when not using SCA entries
commit f07afa0462 upstream.

Even if we don't have extended SCA support, we can have more than 64 CPUs
if we don't enable any HW features that might use the SCA entries.

Now, this works just fine, but we missed a return, which is why we
would actually store the SCA entries. If we have more than 64 CPUs, this
means writing outside of the basic SCA - bad.

Let's fix this. This allows > 64 CPUs when running nested (under vSIE)
without random crashes.

Fixes: a6940674c3 ("KVM: s390: allow 255 VCPUs when sca entries aren't used")
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180306132758.21034-1-david@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-15 10:54:32 +01:00
David Hildenbrand
81a158d214 KVM: s390: consider epoch index on TOD clock syncs
commit 1575767ef3 upstream.

For now, we don't take care of over/underflows. Especially underflows
are critical:

Assume the epoch is currently 0 and we get a sync request for delta=1,
meaning the TOD is moved forward by 1 and we have to fix it up by
subtracting 1 from the epoch. Right now, this will leave the epoch
index untouched, resulting in epoch=-1, epoch_idx=0, which is wrong.

We have to take care of over and underflows, also for the VSIE case. So
let's factor out calculation into a separate function.

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180207114647.6220-5-david@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Fixes: 8fa1696ea7 ("KVM: s390: Multiple Epoch Facility support")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
[use u8 for idx]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-08 22:41:21 -08:00
David Hildenbrand
dbab3751bc KVM: s390: consider epoch index on hotplugged CPUs
commit d16b52cb9c upstream.

We must copy both, the epoch and the epoch_idx.

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180207114647.6220-4-david@redhat.com>
Fixes: 8fa1696ea7 ("KVM: s390: Multiple Epoch Facility support")
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Fixes: 8fa1696ea7 ("KVM: s390: Multiple Epoch Facility support")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-08 22:41:21 -08:00
David Hildenbrand
58a5d1ac69 KVM: s390: provide only a single function for setting the tod (fix SCK)
commit 0e7def5fb0 upstream.

Right now, SET CLOCK called in the guest does not properly take care of
the epoch index, as the call goes via the old kvm_s390_set_tod_clock()
interface. So the epoch index is neither reset to 0, if required, nor
properly set to e.g. 0xff on negative values.

Fix this by providing a single kvm_s390_set_tod_clock() function. Move
Multiple-epoch facility handling into it.

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180207114647.6220-3-david@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Fixes: 8fa1696ea7 ("KVM: s390: Multiple Epoch Facility support")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-08 22:41:21 -08:00
David Hildenbrand
c09ea9a8da KVM: s390: take care of clock-comparator sign control
commit 5fe01793dd upstream.

Missed when enabling the Multiple-epoch facility. If the facility is
installed and the control is set, a sign based comaprison has to be
performed.

Right now we would inject wrong interrupts and ignore interrupt
conditions. Also the sleep time is calculated in a wrong way.

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180207114647.6220-2-david@redhat.com>
Fixes: 8fa1696ea7 ("KVM: s390: Multiple Epoch Facility support")
Cc: stable@vger.kernel.org
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-08 22:41:21 -08:00
Michael S. Tsirkin
dfb48332d6 s390/virtio: add BSD license to virtio-ccw
[ Upstream commit edfb8d8fcb ]

The original intent of the virtio header relicensing
from 2008 was to make sure anyone can implement compatible
devices/drivers. The virtio-ccw was omitted by mistake.

We have an ack from the only contributor as well as the
maintainer from IBM, so it's not too late to fix that.

Make it dual-licensed with GPLv2, as the whole kernel is GPL2.

Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-25 11:07:58 +01:00
Eugene Syromiatnikov
27f97375fc s390: fix handling of -1 in set{,fs}[gu]id16 syscalls
commit 6dd0d2d22a upstream.

For some reason, the implementation of some 16-bit ID system calls
(namely, setuid16/setgid16 and setfsuid16/setfsgid16) used type cast
instead of low2highgid/low2highuid macros for converting [GU]IDs, which
led to incorrect handling of value of -1 (which ought to be considered
invalid).

Discovered by strace test suite.

Cc: stable@vger.kernel.org
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-22 15:42:17 +01:00
Eric Biggers
8d906d183b crypto: hash - annotate algorithms taking optional key
commit a208fa8f33 upstream.

We need to consistently enforce that keyed hashes cannot be used without
setting the key.  To do this we need a reliable way to determine whether
a given hash algorithm is keyed or not.  AF_ALG currently does this by
checking for the presence of a ->setkey() method.  However, this is
actually slightly broken because the CRC-32 algorithms implement
->setkey() but can also be used without a key.  (The CRC-32 "key" is not
actually a cryptographic key but rather represents the initial state.
If not overridden, then a default initial state is used.)

Prepare to fix this by introducing a flag CRYPTO_ALG_OPTIONAL_KEY which
indicates that the algorithm has a ->setkey() method, but it is not
required to be called.  Then set it on all the CRC-32 algorithms.

The same also applies to the Adler-32 implementation in Lustre.

Also, the cryptd and mcryptd templates have to pass through the flag
from their underlying algorithm.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-16 20:23:00 +01:00
Jan H. Schönherr
40ba283e26 KVM: Let KVM_SET_SIGNAL_MASK work as advertised
[ Upstream commit 20b7035c66 ]

KVM API says for the signal mask you set via KVM_SET_SIGNAL_MASK, that
"any unblocked signal received [...] will cause KVM_RUN to return with
-EINTR" and that "the signal will only be delivered if not blocked by
the original signal mask".

This, however, is only true, when the calling task has a signal handler
registered for a signal. If not, signal evaluation is short-circuited for
SIG_IGN and SIG_DFL, and the signal is either ignored without KVM_RUN
returning or the whole process is terminated.

Make KVM_SET_SIGNAL_MASK behave as advertised by utilizing logic similar
to that in do_sigtimedwait() to avoid short-circuiting of signals.

Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-03 17:39:06 +01:00
Martin Schwidefsky
e2443fb287 s390: fix alloc_pgste check in init_new_context again
[ Upstream commit 53c4ab70c1 ]

git commit badb8bb983 "fix alloc_pgste check in init_new_context" fixed
the problem of 'current->mm == NULL' in init_new_context back in 2011.

git commit 3eabaee998 "KVM: s390: allow sie enablement for multi-
threaded programs" completely removed the check against alloc_pgste.

git commit 23fefe119c "s390/kvm: avoid global config of vm.alloc_pgste=1"
re-added a check against the alloc_pgste flag but without the required
check for current->mm != NULL.

For execve() called by a kernel thread init_new_context() reads from
((struct mm_struct *) NULL)->context.alloc_pgste to decide between
2K vs 4K page tables. If the bit happens to be set for the init process
it will be created with large page tables. This decision is inherited by
all the children of init, this waste quite some memory.

Re-add the check for 'current->mm != NULL'.

Fixes: 23fefe119c ("s390/kvm: avoid global config of vm.alloc_pgste=1")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-03 17:39:00 +01:00
Thomas Richter
18c128456e s390/topology: fix compile error in file arch/s390/kernel/smp.c
[ Upstream commit 38389ec84e ]

Commit 1887aa07b6
("s390/topology: add detection of dedicated vs shared CPUs")
introduced following compiler error when CONFIG_SCHED_TOPOLOGY is not set.

 CC      arch/s390/kernel/smp.o
...
arch/s390/kernel/smp.c: In function ‘smp_start_secondary’:
arch/s390/kernel/smp.c:812:6: error: implicit declaration of function
	‘topology_cpu_dedicated’; did you mean ‘topology_cpu_init’?

This patch fixes the compiler error by adding function
topology_cpu_dedicated() to return false when this config option is
not defined.

Signed-off-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-03 17:38:59 +01:00
Christian Borntraeger
d529ba9b27 KVM: s390: add proper locking for CMMA migration bitmap
commit 1de1ea7efe upstream.

Some parts of the cmma migration bitmap is already protected
with the kvm->lock (e.g. the migration start). On the other
hand the read of the cmma bits is not protected against a
concurrent free, neither is the emulation of the ESSA instruction.
Let's extend the locking to all related ioctls by using
the slots lock for
- kvm_s390_vm_start_migration
- kvm_s390_vm_stop_migration
- kvm_s390_set_cmma_bits
- kvm_s390_get_cmma_bits

In addition to that, we use synchronize_srcu before freeing
the migration structure as all users hold kvm->srcu for read.
(e.g. the ESSA handler).

Reported-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Fixes: 190df4a212 (KVM: s390: CMMA tracking, ESSA emulation, migration mode)
Reviewed-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-31 14:03:42 +01:00
Christian Borntraeger
77bbeea781 KVM: s390: prevent buffer overrun on memory hotplug during migration
commit c2cf265d86 upstream.

We must not go beyond the pre-allocated buffer. This can happen when
a new memory slot is added during migration.

Reported-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Fixes: 190df4a212 (KVM: s390: CMMA tracking, ESSA emulation, migration mode)
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-10 09:31:23 +01:00
Christian Borntraeger
853bcadeef KVM: s390: fix cmma migration for multiple memory slots
commit 32aa144fc3 upstream.

When multiple memory slots are present the cmma migration code
does not allocate enough memory for the bitmap. The memory slots
are sorted in reverse order, so we must use gfn and size of
slot[0] instead of the last one.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Fixes: 190df4a212 (KVM: s390: CMMA tracking, ESSA emulation, migration mode)
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-10 09:31:23 +01:00