6160 Commits

Author SHA1 Message Date
Ilya Leoshkevich
ddf58efd05 s390/bpf: Fix optimizing out zero-extensions
commit db7bee653859ef7179be933e7d1384644f795f26 upstream.

Currently the JIT completely removes things like `reg32 += 0`,
however, the BPF_ALU semantics requires the target register to be
zero-extended in such cases.

Fix by optimizing out only the arithmetic operation, but not the
subsequent zero-extension.

Reported-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-26 13:39:46 +02:00
Ilya Leoshkevich
e15c2fe2de s390/bpf: Fix 64-bit subtraction of the -0x80000000 constant
commit 6e61dc9da0b7a0d91d57c2e20b5ea4fd2d4e7e53 upstream.

The JIT uses agfi for subtracting constants, but -(-0x80000000) cannot
be represented as a 32-bit signed binary integer. Fix by using algfi in
this particular case.

Reported-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-22 11:48:14 +02:00
Halil Pasic
3d95bdee23 KVM: s390: index kvm->arch.idle_mask by vcpu_idx
commit a3e03bc1368c1bc16e19b001fc96dc7430573cc8 upstream.

While in practice vcpu->vcpu_idx ==  vcpu->vcp_id is often true, it may
not always be, and we must not rely on this. Reason is that KVM decides
the vcpu_idx, userspace decides the vcpu_id, thus the two might not
match.

Currently kvm->arch.idle_mask is indexed by vcpu_id, which implies
that code like
for_each_set_bit(vcpu_id, kvm->arch.idle_mask, online_vcpus) {
                vcpu = kvm_get_vcpu(kvm, vcpu_id);
		do_stuff(vcpu);
}
is not legit. Reason is that kvm_get_vcpu expects an vcpu_idx, not an
vcpu_id.  The trouble is, we do actually use kvm->arch.idle_mask like
this. To fix this problem we have two options. Either use
kvm_get_vcpu_by_id(vcpu_id), which would loop to find the right vcpu_id,
or switch to indexing via vcpu_idx. The latter is preferable for obvious
reasons.

Let us make switch from indexing kvm->arch.idle_mask by vcpu_id to
indexing it by vcpu_idx.  To keep gisa_int.kicked_mask indexed by the
same index as idle_mask lets make the same change for it as well.

Fixes: 1ee0bc559dc3 ("KVM: s390: get rid of local_int array")
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Christian Bornträger <borntraeger@de.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: <stable@vger.kernel.org> # 3.15+
Link: https://lore.kernel.org/r/20210827125429.1912577-1-pasic@linux.ibm.com
[borntraeger@de.ibm.com]: change  idle mask, remove kicked_mask 
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-22 11:48:12 +02:00
Heiko Carstens
8dc4b13dae s390/jump_label: print real address in a case of a jump label bug
[ Upstream commit 5492886c14744d239e87f1b0b774b5a341e755cc ]

In case of a jump label print the real address of the piece of code
where a mismatch was detected. This is right before the system panics,
so there is nothing revealed.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-22 11:48:04 +02:00
Daniel Borkmann
91cdb5b362 bpf: Introduce BPF nospec instruction for mitigating Spectre v4
commit f5e81d1117501546b7be050c5fbafa6efd2c722c upstream.

In case of JITs, each of the JIT backends compiles the BPF nospec instruction
/either/ to a machine instruction which emits a speculation barrier /or/ to
/no/ machine instruction in case the underlying architecture is not affected
by Speculative Store Bypass or has different mitigations in place already.

This covers both x86 and (implicitly) arm64: In case of x86, we use 'lfence'
instruction for mitigation. In case of arm64, we rely on the firmware mitigation
as controlled via the ssbd kernel parameter. Whenever the mitigation is enabled,
it works for all of the kernel code with no need to provide any additional
instructions here (hence only comment in arm64 JIT). Other archs can follow
as needed. The BPF nospec instruction is specifically targeting Spectre v4
since i) we don't use a serialization barrier for the Spectre v1 case, and
ii) mitigation instructions for v1 and v4 might be different on some archs.

The BPF nospec is required for a future commit, where the BPF verifier does
annotate intermediate BPF programs with speculation barriers.

Co-developed-by: Piotr Krysiuk <piotras@gmail.com>
Co-developed-by: Benedict Schlueter <benedict.schlueter@rub.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Piotr Krysiuk <piotras@gmail.com>
Signed-off-by: Benedict Schlueter <benedict.schlueter@rub.de>
Acked-by: Alexei Starovoitov <ast@kernel.org>
[OP: adjusted context for 4.19, drop riscv and ppc32 changes]
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-22 11:47:58 +02:00
Vasily Gorbik
aa2f15f54d s390/ftrace: fix ftrace_update_ftrace_func implementation
commit f8c2602733c953ed7a16e060640b8e96f9d94b9b upstream.

s390 enforces DYNAMIC_FTRACE if FUNCTION_TRACER is selected.
At the same time implementation of ftrace_caller is not compliant with
HAVE_DYNAMIC_FTRACE since it doesn't provide implementation of
ftrace_update_ftrace_func() and calls ftrace_trace_function() directly.

The subtle difference is that during ftrace code patching ftrace
replaces function tracer via ftrace_update_ftrace_func() and activates
it back afterwards. Unexpected direct calls to ftrace_trace_function()
during ftrace code patching leads to nullptr-dereferences when tracing
is activated for one of functions which are used during code patching.
Those function currently are:
copy_from_kernel_nofault()
copy_from_kernel_nofault_allowed()
preempt_count_sub() [with debug_defconfig]
preempt_count_add() [with debug_defconfig]

Corresponding KASAN report:
 BUG: KASAN: nullptr-dereference in function_trace_call+0x316/0x3b0
 Read of size 4 at addr 0000000000001e08 by task migration/0/15

 CPU: 0 PID: 15 Comm: migration/0 Tainted: G B 5.13.0-41423-g08316af3644d
 Hardware name: IBM 3906 M04 704 (LPAR)
 Stopper: multi_cpu_stop+0x0/0x3e0 <- stop_machine_cpuslocked+0x1e4/0x218
 Call Trace:
  [<0000000001f77caa>] show_stack+0x16a/0x1d0
  [<0000000001f8de42>] dump_stack+0x15a/0x1b0
  [<0000000001f81d56>] print_address_description.constprop.0+0x66/0x2e0
  [<000000000082b0ca>] kasan_report+0x152/0x1c0
  [<00000000004cfd8e>] function_trace_call+0x316/0x3b0
  [<0000000001fb7082>] ftrace_caller+0x7a/0x7e
  [<00000000006bb3e6>] copy_from_kernel_nofault_allowed+0x6/0x10
  [<00000000006bb42e>] copy_from_kernel_nofault+0x3e/0xd0
  [<000000000014605c>] ftrace_make_call+0xb4/0x1f8
  [<000000000047a1b4>] ftrace_replace_code+0x134/0x1d8
  [<000000000047a6e0>] ftrace_modify_all_code+0x120/0x1d0
  [<000000000047a7ec>] __ftrace_modify_code+0x5c/0x78
  [<000000000042395c>] multi_cpu_stop+0x224/0x3e0
  [<0000000000423212>] cpu_stopper_thread+0x33a/0x5a0
  [<0000000000243ff2>] smpboot_thread_fn+0x302/0x708
  [<00000000002329ea>] kthread+0x342/0x408
  [<00000000001066b2>] __ret_from_fork+0x92/0xf0
  [<0000000001fb57fa>] ret_from_fork+0xa/0x30

 The buggy address belongs to the page:
 page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1
 flags: 0x1ffff00000001000(reserved|node=0|zone=0|lastcpupid=0x1ffff)
 raw: 1ffff00000001000 0000040000000048 0000040000000048 0000000000000000
 raw: 0000000000000000 0000000000000000 ffffffff00000001 0000000000000000
 page dumped because: kasan: bad access detected

 Memory state around the buggy address:
  0000000000001d00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0000000000001d80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
 >0000000000001e00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
                       ^
  0000000000001e80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0000000000001f00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
 ==================================================================

To fix that introduce ftrace_func callback to be called from
ftrace_caller and update it in ftrace_update_ftrace_func().

Fixes: 4cc9bed034d1 ("[S390] cleanup ftrace backend functions")
Cc: stable@vger.kernel.org
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-28 11:13:49 +02:00
Colin Ian King
0d0927f545 s390/bpf: Perform r1 range checking before accessing jit->seen_reg[r1]
[ Upstream commit 91091656252f5d6d8c476e0c92776ce9fae7b445 ]

Currently array jit->seen_reg[r1] is being accessed before the range
checking of index r1. The range changing on r1 should be performed
first since it will avoid any potential out-of-range accesses on the
array seen_reg[] and also it is more optimal to perform checks on r1
before fetching data from the array. Fix this by swapping the order
of the checks before the array access.

Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/bpf/20210715125712.24690-1-colin.king@canonical.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-28 11:13:47 +02:00
Valentin Vidic
b2936c01a5 s390/sclp_vt220: fix console name to match device
[ Upstream commit b7d91d230a119fdcc334d10c9889ce9c5e15118b ]

Console name reported in /proc/consoles:

  ttyS1                -W- (EC p  )    4:65

does not match the char device name:

  crw--w----    1 root     root        4,  65 May 17 12:18 /dev/ttysclp0

so debian-installer inside a QEMU s390x instance gets confused and fails
to start with the following error:

  steal-ctty: No such file or directory

Signed-off-by: Valentin Vidic <vvidic@valentin-vidic.from.hr>
Link: https://lore.kernel.org/r/20210427194010.9330-1-vvidic@valentin-vidic.from.hr
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-20 16:16:08 +02:00
Randy Dunlap
3842ed3642 s390: appldata depends on PROC_SYSCTL
[ Upstream commit 5d3516b3647621d5a1180672ea9e0817fb718ada ]

APPLDATA_BASE should depend on PROC_SYSCTL instead of PROC_FS.
Building with PROC_FS but not PROC_SYSCTL causes a build error,
since appldata_base.c uses data and APIs from fs/proc/proc_sysctl.c.

arch/s390/appldata/appldata_base.o: in function `appldata_generic_handler':
appldata_base.c:(.text+0x192): undefined reference to `sysctl_vals'

Fixes: c185b783b099 ("[S390] Remove config options.")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Link: https://lore.kernel.org/r/20210528002420.17634-1-rdunlap@infradead.org
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-20 16:15:55 +02:00
Claudio Imbrenda
45eef8fabf KVM: s390: split kvm_s390_real_to_abs
commit c5d1f6b531e68888cbe6718b3f77a60115d58b9c upstream.

A new function _kvm_s390_real_to_abs will apply prefixing to a real address
with a given prefix value.

The old kvm_s390_real_to_abs becomes now a wrapper around the new function.

This is needed to avoid code duplication in vSIE.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210322140559.500716-2-imbrenda@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-22 10:59:26 +02:00
Heiko Carstens
0ebfdc8408 KVM: s390: fix guarded storage control register handling
commit 44bada28219031f9e8e86b84460606efa57b871e upstream.

store_regs_fmt2() has an ordering problem: first the guarded storage
facility is enabled on the local cpu, then preemption disabled, and
then the STGSC (store guarded storage controls) instruction is
executed.

If the process gets scheduled away between enabling the guarded
storage facility and before preemption is disabled, this might lead to
a special operation exception and therefore kernel crash as soon as
the process is scheduled back and the STGSC instruction is executed.

Fixes: 4e0b1ab72b8a ("KVM: s390: gs support for kvm guests")
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Cc: <stable@vger.kernel.org> # 4.12
Link: https://lore.kernel.org/r/20210415080127.1061275-1-hca@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-22 10:59:26 +02:00
Claudio Imbrenda
587ae3236b KVM: s390: split kvm_s390_logical_to_effective
commit f85f1baaa18932a041fd2b1c2ca6cfd9898c7d2b upstream.

Split kvm_s390_logical_to_effective to a generic function called
_kvm_s390_logical_to_effective. The new function takes a PSW and an address
and returns the address with the appropriate bits masked off. The old
function now calls the new function with the appropriate PSW from the vCPU.

This is needed to avoid code duplication for vSIE.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: stable@vger.kernel.org # for VSIE: correctly handle MVPG when in VSIE
Link: https://lore.kernel.org/r/20210302174443.514363-2-imbrenda@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-22 10:59:26 +02:00
Harald Freudenberger
5bceddd8e4 s390/archrandom: add parameter check for s390_arch_random_generate
[ Upstream commit 28096067686c5a5cbd4c35b079749bd805df5010 ]

A review of the code showed, that this function which is exposed
within the whole kernel should do a parameter check for the
amount of bytes requested. If this requested bytes is too high
an unsigned int overflow could happen causing this function to
try to memcpy a really big memory chunk.

This is not a security issue as there are only two invocations
of this function from arch/s390/include/asm/archrandom.h and both
are not exposed to userland.

Reported-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-22 10:59:19 +02:00
Vasily Gorbik
2afdf47ef5 s390/disassembler: increase ebpf disasm buffer size
commit 6f3353c2d2b3eb4de52e9704cb962712033db181 upstream.

Current ebpf disassembly buffer size of 64 is too small. E.g. this line
takes 65 bytes:
01fffff8005822e: ec8100ed8065\tclgrj\t%r8,%r1,8,001fffff80058408\n\0

Double the buffer size like it is done for the kernel disassembly buffer.

Fixes the following KASAN finding:

UG: KASAN: stack-out-of-bounds in print_fn_code+0x34c/0x380
Write of size 1 at addr 001fff800ad5f970 by task test_progs/853

CPU: 53 PID: 853 Comm: test_progs Not tainted
5.12.0-rc7-23786-g23457d86b1f0-dirty #19
Hardware name: IBM 3906 M04 704 (LPAR)
Call Trace:
 [<0000000cd8e0538a>] show_stack+0x17a/0x1668
 [<0000000cd8e2a5d8>] dump_stack+0x140/0x1b8
 [<0000000cd8e16e74>] print_address_description.constprop.0+0x54/0x260
 [<0000000cd75a8698>] kasan_report+0xc8/0x130
 [<0000000cd6e26da4>] print_fn_code+0x34c/0x380
 [<0000000cd6ea0f4e>] bpf_int_jit_compile+0xe3e/0xe58
 [<0000000cd72c4c88>] bpf_prog_select_runtime+0x5b8/0x9c0
 [<0000000cd72d1bf8>] bpf_prog_load+0xa78/0x19c0
 [<0000000cd72d7ad6>] __do_sys_bpf.part.0+0x18e/0x768
 [<0000000cd6e0f392>] do_syscall+0x12a/0x220
 [<0000000cd8e333f8>] __do_syscall+0x98/0xc8
 [<0000000cd8e54834>] system_call+0x6c/0x94
1 lock held by test_progs/853:
 #0: 0000000cd9bf7460 (report_lock){....}-{2:2}, at:
     kasan_report+0x96/0x130

addr 001fff800ad5f970 is located in stack of task test_progs/853 at
offset 96 in frame:
 print_fn_code+0x0/0x380
this frame has 1 object:
 [32, 96) 'buffer'

Memory state around the buggy address:
 001fff800ad5f800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 001fff800ad5f880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>001fff800ad5f900: 00 00 f1 f1 f1 f1 00 00 00 00 00 00 00 00 f3 f3
                                                             ^
 001fff800ad5f980: f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 001fff800ad5fa00: 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00

Cc: <stable@vger.kernel.org>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-22 10:59:12 +02:00
Vasily Gorbik
1ff0833ea3 s390/entry: save the caller of psw_idle
[ Upstream commit a994eddb947ea9ebb7b14d9a1267001699f0a136 ]

Currently psw_idle does not allocate a stack frame and does not
save its r14 and r15 into the save area. Even though this is valid from
call ABI point of view, because psw_idle does not make any calls
explicitly, in reality psw_idle is an entry point for controlled
transition into serving interrupts. So, in practice, psw_idle stack
frame is analyzed during stack unwinding. Depending on build options
that r14 slot in the save area of psw_idle might either contain a value
saved by previous sibling call or complete garbage.

  [task    0000038000003c28] do_ext_irq+0xd6/0x160
  [task    0000038000003c78] ext_int_handler+0xba/0xe8
  [task   *0000038000003dd8] psw_idle_exit+0x0/0x8 <-- pt_regs
 ([task    0000038000003dd8] 0x0)
  [task    0000038000003e10] default_idle_call+0x42/0x148
  [task    0000038000003e30] do_idle+0xce/0x160
  [task    0000038000003e70] cpu_startup_entry+0x36/0x40
  [task    0000038000003ea0] arch_call_rest_init+0x76/0x80

So, to make a stacktrace nicer and actually point for the real caller of
psw_idle in this frequently occurring case, make psw_idle save its r14.

  [task    0000038000003c28] do_ext_irq+0xd6/0x160
  [task    0000038000003c78] ext_int_handler+0xba/0xe8
  [task   *0000038000003dd8] psw_idle_exit+0x0/0x6 <-- pt_regs
 ([task    0000038000003dd8] arch_cpu_idle+0x3c/0xd0)
  [task    0000038000003e10] default_idle_call+0x42/0x148
  [task    0000038000003e30] do_idle+0xce/0x160
  [task    0000038000003e70] cpu_startup_entry+0x36/0x40
  [task    0000038000003ea0] arch_call_rest_init+0x76/0x80

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-04-28 13:16:52 +02:00
Alexander Gordeev
e0b19c2e3b s390/cpcmd: fix inline assembly register clobbering
[ Upstream commit 7a2f91441b2c1d81b77c1cd816a4659f4abc9cbe ]

Register variables initialized using arithmetic. That leads to
kasan instrumentaton code corrupting the registers contents.
Follow GCC guidlines and use temporary variables for assigning
init values to register variables.

Fixes: 94c12cc7d196 ("[S390] Inline assembly cleanup.")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://gcc.gnu.org/onlinedocs/gcc-10.2.0/gcc/Local-Register-Variables.html
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-04-14 08:22:35 +02:00
Heiko Carstens
9b2384daf9 s390/smp: __smp_rescan_cpus() - move cpumask away from stack
[ Upstream commit 62c8dca9e194326802b43c60763f856d782b225c ]

Avoid a potentially large stack frame and overflow by making
"cpumask_t avail" a static variable. There is no concurrent
access due to the existing locking.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-03-17 16:43:46 +01:00
Philipp Rudo
a874333de0 s390/kexec_file: fix diag308 subcode when loading crash kernel
commit 613775d62ec60202f98d2c5f520e6e9ba6dd4ac4 upstream.

diag308 subcode 0 performes a clear reset which inlcudes the reset of
all registers in the system. While this is the preferred behavior when
loading a normal kernel via kexec it prevents the crash kernel to store
the register values in the dump. To prevent this use subcode 1 when
loading a crash kernel instead.

Fixes: ee337f5469fd ("s390/kexec_file: Add crash support to image loader")
Cc: <stable@vger.kernel.org> # 4.17
Signed-off-by: Philipp Rudo <prudo@linux.ibm.com>
Reported-by: Xiaoying Yan <yiyan@redhat.com>
Tested-by: Lianbo Jiang <lijiang@redhat.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-30 11:26:09 +01:00
Sven Schnelle
7f3547b3eb s390/smp: perform initial CPU reset also for SMT siblings
commit b5e438ebd7e808d1d2435159ac4742e01a94b8da upstream.

Not resetting the SMT siblings might leave them in unpredictable
state. One of the observed problems was that the CPU timer wasn't
reset and therefore large system time values where accounted during
CPU bringup.

Cc: <stable@kernel.org> # 4.0
Fixes: 10ad34bc76dfb ("s390: add SMT support")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-30 11:26:09 +01:00
Thomas Richter
a1bf9efcf4 s390/cpum_sf.c: fix file permission for cpum_sfb_size
commit 78d732e1f326f74f240d416af9484928303d9951 upstream.

This file is installed by the s390 CPU Measurement sampling
facility device driver to export supported minimum and
maximum sample buffer sizes.
This file is read by lscpumf tool to display the details
of the device driver capabilities. The lscpumf tool might
be invoked by a non-root user. In this case it does not
print anything because the file contents can not be read.

Fix this by allowing read access for all users. Reading
the file contents is ok, changing the file contents is
left to the root user only.

For further reference and details see:
 [1] https://github.com/ibm-s390-tools/s390-tools/issues/97

Fixes: 69f239ed335a ("s390/cpum_sf: Dynamically extend the sampling buffer if overflows occur")
Cc: <stable@vger.kernel.org> # 3.14
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-24 13:27:26 +01:00
Qian Cai
2343665ea3 s390/smp: move rcu_cpu_starting() earlier
[ Upstream commit de5d9dae150ca1c1b5c7676711a9ca139d1a8dec ]

The call to rcu_cpu_starting() in smp_init_secondary() is not early
enough in the CPU-hotplug onlining process, which results in lockdep
splats as follows:

 WARNING: suspicious RCU usage
 -----------------------------
 kernel/locking/lockdep.c:3497 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 RCU used illegally from offline CPU!
 rcu_scheduler_active = 1, debug_locks = 1
 no locks held by swapper/1/0.

 Call Trace:
 show_stack+0x158/0x1f0
 dump_stack+0x1f2/0x238
 __lock_acquire+0x2640/0x4dd0
 lock_acquire+0x3a8/0xd08
 _raw_spin_lock_irqsave+0xc0/0xf0
 clockevents_register_device+0xa8/0x528
 init_cpu_timer+0x33e/0x468
 smp_init_secondary+0x11a/0x328
 smp_start_secondary+0x82/0x88

This is avoided by moving the call to rcu_cpu_starting up near the
beginning of the smp_init_secondary() function. Note that the
raw_smp_processor_id() is required in order to avoid calling into
lockdep before RCU has declared the CPU to be watched for readers.

Link: https://lore.kernel.org/lkml/160223032121.7002.1269740091547117869.tip-bot2@tip-bot2/
Signed-off-by: Qian Cai <cai@redhat.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-11-18 19:18:45 +01:00
Sven Schnelle
9b7089ce09 s390/stp: add locking to sysfs functions
commit b3bd02495cb339124f13135d51940cf48d83e5cb upstream.

The sysfs function might race with stp_work_fn. To prevent that,
add the required locking. Another issue is that the sysfs functions
are checking the stp_online flag, but this flag just holds the user
setting whether STP is enabled. Add a flag to clock_sync_flag whether
stp_info holds valid data and use that instead.

Cc: stable@vger.kernel.org
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-05 11:08:51 +01:00
Ilya Leoshkevich
b08005625f s390/init: add missing __init annotations
[ Upstream commit fcb2b70cdb194157678fb1a75f9ff499aeba3d2a ]

Add __init to reserve_memory_end, reserve_oldmem and remove_oldmem.
Sometimes these functions are not inlined, and then the build
complains about section mismatch.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01 13:14:50 +02:00
Thomas Richter
a356441de6 s390/cpum_sf: Use kzalloc and minor changes
[ Upstream commit 32dab6828c42f087439d3e2617dc7283546bd8f7 ]

Use kzalloc() to allocate auxiliary buffer structure initialized
with all zeroes to avoid random value in trace output.

Avoid double access to SBD hardware flags.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01 13:14:30 +02:00
Sven Schnelle
228d5227dc s390: don't trace preemption in percpu macros
[ Upstream commit 1196f12a2c960951d02262af25af0bb1775ebcc2 ]

Since commit a21ee6055c30 ("lockdep: Change hardirq{s_enabled,_context}
to per-cpu variables") the lockdep code itself uses percpu variables. This
leads to recursions because the percpu macros are calling preempt_enable()
which might call trace_preempt_on().

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-09-09 19:04:23 +02:00
Heiko Carstens
c5599b901d s390/ptrace: fix storage key handling
[ Upstream commit fd78c59446b8d050ecf3e0897c5a486c7de7c595 ]

The key member of the runtime instrumentation control block contains
only the access key, not the complete storage key. Therefore the value
must be shifted by four bits. Since existing user space does not
necessarily query and set the access key correctly, just ignore the
user space provided key and use the correct one.
Note: this is only relevant for debugging purposes in case somebody
compiles a kernel with a default storage access key set to a value not
equal to zero.

Fixes: 262832bc5acd ("s390/ptrace: add runtime instrumention register get/set")
Reported-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-08-26 10:31:03 +02:00
Heiko Carstens
5a5120b162 s390/runtime_instrumentation: fix storage key handling
[ Upstream commit 9eaba29c7985236e16468f4e6a49cc18cf01443e ]

The key member of the runtime instrumentation control block contains
only the access key, not the complete storage key. Therefore the value
must be shifted by four bits.
Note: this is only relevant for debugging purposes in case somebody
compiles a kernel with a default storage access key set to a value not
equal to zero.

Fixes: e4b8b3f33fca ("s390: add support for runtime instrumentation")
Reported-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-08-26 10:31:03 +02:00
Janosch Frank
1a57516407 s390/mm: fix huge pte soft dirty copying
commit 528a9539348a0234375dfaa1ca5dbbb2f8f8e8d2 upstream.

If the pmd is soft dirty we must mark the pte as soft dirty (and not dirty).
This fixes some cases for guest migration with huge page backings.

Cc: <stable@vger.kernel.org> # 4.8
Fixes: bc29b7ac1d9f ("s390/mm: clean up pte/pmd encoding")
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-16 08:17:28 +02:00
Vasily Gorbik
7e7f71be56 s390/kasan: fix early pgm check handler execution
[ Upstream commit 998f5bbe3dbdab81c1cfb1aef7c3892f5d24f6c7 ]

Currently if early_pgm_check_handler is called it ends up in pgm check
loop. The problem is that early_pgm_check_handler is instrumented by
KASAN but executed without DAT flag enabled which leads to addressing
exception when KASAN checks try to access shadow memory.

Fix that by executing early handlers with DAT flag on under KASAN as
expected.

Reported-and-tested-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-07-16 08:17:22 +02:00
Christian Borntraeger
34314cc6da KVM: s390: reduce number of IO pins to 1
[ Upstream commit 774911290c589e98e3638e73b24b0a4d4530e97c ]

The current number of KVM_IRQCHIP_NUM_PINS results in an order 3
allocation (32kb) for each guest start/restart. This can result in OOM
killer activity even with free swap when the memory is fragmented
enough:

kernel: qemu-system-s39 invoked oom-killer: gfp_mask=0x440dc0(GFP_KERNEL_ACCOUNT|__GFP_COMP|__GFP_ZERO), order=3, oom_score_adj=0
kernel: CPU: 1 PID: 357274 Comm: qemu-system-s39 Kdump: loaded Not tainted 5.4.0-29-generic #33-Ubuntu
kernel: Hardware name: IBM 8562 T02 Z06 (LPAR)
kernel: Call Trace:
kernel: ([<00000001f848fe2a>] show_stack+0x7a/0xc0)
kernel:  [<00000001f8d3437a>] dump_stack+0x8a/0xc0
kernel:  [<00000001f8687032>] dump_header+0x62/0x258
kernel:  [<00000001f8686122>] oom_kill_process+0x172/0x180
kernel:  [<00000001f8686abe>] out_of_memory+0xee/0x580
kernel:  [<00000001f86e66b8>] __alloc_pages_slowpath+0xd18/0xe90
kernel:  [<00000001f86e6ad4>] __alloc_pages_nodemask+0x2a4/0x320
kernel:  [<00000001f86b1ab4>] kmalloc_order+0x34/0xb0
kernel:  [<00000001f86b1b62>] kmalloc_order_trace+0x32/0xe0
kernel:  [<00000001f84bb806>] kvm_set_irq_routing+0xa6/0x2e0
kernel:  [<00000001f84c99a4>] kvm_arch_vm_ioctl+0x544/0x9e0
kernel:  [<00000001f84b8936>] kvm_vm_ioctl+0x396/0x760
kernel:  [<00000001f875df66>] do_vfs_ioctl+0x376/0x690
kernel:  [<00000001f875e304>] ksys_ioctl+0x84/0xb0
kernel:  [<00000001f875e39a>] __s390x_sys_ioctl+0x2a/0x40
kernel:  [<00000001f8d55424>] system_call+0xd8/0x2c8

As far as I can tell s390x does not use the iopins as we bail our for
anything other than KVM_IRQ_ROUTING_S390_ADAPTER and the chip/pin is
only used for KVM_IRQ_ROUTING_IRQCHIP. So let us use a small number to
reduce the memory footprint.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200617083620.5409-1-borntraeger@de.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-07-16 08:17:20 +02:00
Christian Borntraeger
34035e7842 s390/debug: avoid kernel warning on too large number of pages
[ Upstream commit 827c4913923e0b441ba07ba4cc41e01181102303 ]

When specifying insanely large debug buffers a kernel warning is
printed. The debug code does handle the error gracefully, though.
Instead of duplicating the check let us silence the warning to
avoid crashes when panic_on_warn is used.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-07-09 09:37:09 +02:00
Vincenzo Frascino
f9e97d64c3 s390/vdso: fix vDSO clock_getres()
[ Upstream commit 478237a595120a18e9b52fd2c57a6e8b7a01e411 ]

clock_getres in the vDSO library has to preserve the same behaviour
of posix_get_hrtimer_res().

In particular, posix_get_hrtimer_res() does:
    sec = 0;
    ns = hrtimer_resolution;
and hrtimer_resolution depends on the enablement of the high
resolution timers that can happen either at compile or at run time.

Fix the s390 vdso implementation of clock_getres keeping a copy of
hrtimer_resolution in vdso data and using that directly.

Link: https://lkml.kernel.org/r/20200324121027.21665-1-vincenzo.frascino@arm.com
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[heiko.carstens@de.ibm.com: use llgf for proper zero extension]
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-30 23:17:14 -04:00
Sven Schnelle
42cd50aaa1 s390/ptrace: fix setting syscall number
[ Upstream commit 873e5a763d604c32988c4a78913a8dab3862d2f9 ]

When strace wants to update the syscall number, it sets GPR2
to the desired number and updates the GPR via PTRACE_SETREGSET.
It doesn't update regs->int_code which would cause the old syscall
executed on syscall restart. As we cannot change the ptrace ABI and
don't have a field for the interruption code, check whether the tracee
is in a syscall and the last instruction was svc. In that case assume
that the tracer wants to update the syscall number and copy the GPR2
value to regs->int_code.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-30 23:17:14 -04:00
1d3c79f492 s390: fix syscall_get_error for compat processes
commit b3583fca5fb654af2cfc1c08259abb9728272538 upstream.

If both the tracer and the tracee are compat processes, and gprs[2]
is assigned a value by __poke_user_compat, then the higher 32 bits
of gprs[2] are cleared, IS_ERR_VALUE() always returns false, and
syscall_get_error() always returns 0.

Fix the implementation by sign-extending the value for compat processes
the same way as x86 implementation does.

The bug was exposed to user space by commit 201766a20e30f ("ptrace: add
PTRACE_GET_SYSCALL_INFO request") and detected by strace test suite.

This change fixes strace syscall tampering on s390.

Link: https://lkml.kernel.org/r/20200602180051.GA2427@altlinux.org
Fixes: 753c4dd6a2fa2 ("[S390] ptrace changes")
Cc: Elvira Khabirova <lineprinter@altlinux.org>
Cc: stable@vger.kernel.org # v2.6.28+
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-25 15:33:09 +02:00
Gerald Schaefer
84fc4e58e4 s390/mm: fix set_huge_pte_at() for empty ptes
[ Upstream commit ac8372f3b4e41015549b331a4f350224661e7fc6 ]

On s390, the layout of normal and large ptes (i.e. pmds/puds) differs.
Therefore, set_huge_pte_at() does a conversion from a normal pte to
the corresponding large pmd/pud. So, when converting an empty pte, this
should result in an empty pmd/pud, which would return true for
pmd/pud_none().

However, after conversion we also mark the pmd/pud as large, and
therefore present. For empty ptes, this will result in an empty pmd/pud
that is also marked as large, and pmd/pud_none() would not return true.

There is currently no issue with this behaviour, as set_huge_pte_at()
does not seem to be called for empty ptes. It would be valid though, so
let's fix this by not marking empty ptes as large in set_huge_pte_at().

This was found by testing a patch from from Anshuman Khandual, which is
currently discussed on LKML ("mm/debug: Add more arch page table helper
tests").

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-07 13:17:56 +02:00
Vasily Gorbik
3825ddf5fd s390/ftrace: save traced function caller
[ Upstream commit b4adfe55915d8363e244e42386d69567db1719b9 ]

A typical backtrace acquired from ftraced function currently looks like
the following (e.g. for "path_openat"):

arch_stack_walk+0x15c/0x2d8
stack_trace_save+0x50/0x68
stack_trace_call+0x15a/0x3b8
ftrace_graph_caller+0x0/0x1c
0x3e0007e3c98 <- ftraced function caller (should be do_filp_open+0x7c/0xe8)
do_open_execat+0x70/0x1b8
__do_execve_file.isra.0+0x7d8/0x860
__s390x_sys_execve+0x56/0x68
system_call+0xdc/0x2d8

Note random "0x3e0007e3c98" stack value as ftraced function caller. This
value causes either imprecise unwinder result or unwinding failure.
That "0x3e0007e3c98" comes from r14 of ftraced function stack frame, which
it haven't had a chance to initialize since the very first instruction
calls ftrace code ("ftrace_caller"). (ftraced function might never
save r14 as well). Nevertheless according to s390 ABI any function
is called with stack frame allocated for it and r14 contains return
address. "ftrace_caller" itself is called with "brasl %r0,ftrace_caller".
So, to fix this issue simply always save traced function caller onto
ftraced function stack frame.

Reported-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-07 13:17:55 +02:00
Philipp Rudo
bbe15f16e5 s390/ftrace: fix potential crashes when switching tracers
[ Upstream commit 8ebf6da9db1b2a20bb86cc1bee2552e894d03308 ]

Switching tracers include instruction patching. To prevent that a
instruction is patched while it's read the instruction patching is done
in stop_machine 'context'. This also means that any function called
during stop_machine must not be traced. Thus add 'notrace' to all
functions called within stop_machine.

Fixes: 1ec2772e0c3c ("s390/diag: add a statistic for diagnose calls")
Fixes: 38f2c691a4b3 ("s390: improve wait logic of stop_machine")
Fixes: 4ecf0a43e729 ("processor: get rid of cpu_relax_yield")
Signed-off-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-05-10 10:30:09 +02:00
Christian Borntraeger
215d1f3928 s390/mm: fix page table upgrade vs 2ndary address mode accesses
commit 316ec154810960052d4586b634156c54d0778f74 upstream.

A page table upgrade in a kernel section that uses secondary address
mode will mess up the kernel instructions as follows:

Consider the following scenario: two threads are sharing memory.
On CPU1 thread 1 does e.g. strnlen_user().  That gets to
        old_fs = enable_sacf_uaccess();
        len = strnlen_user_srst(src, size);
and
                "   la    %2,0(%1)\n"
                "   la    %3,0(%0,%1)\n"
                "   slgr  %0,%0\n"
                "   sacf  256\n"
                "0: srst  %3,%2\n"
in strnlen_user_srst().  At that point we are in secondary space mode,
control register 1 points to kernel page table and instruction fetching
happens via c1, rather than usual c13.  Interrupts are not disabled, for
obvious reasons.

On CPU2 thread 2 does MAP_FIXED mmap(), forcing the upgrade of page table
from 3-level to e.g. 4-level one.  We'd allocated new top-level table,
set it up and now we hit this:
                notify = 1;
                spin_unlock_bh(&mm->page_table_lock);
        }
        if (notify)
                on_each_cpu(__crst_table_upgrade, mm, 0);
OK, we need to actually change over to use of new page table and we
need that to happen in all threads that are currently running.  Which
happens to include the thread 1.  IPI is delivered and we have
static void __crst_table_upgrade(void *arg)
{
        struct mm_struct *mm = arg;

        if (current->active_mm == mm)
                set_user_asce(mm);
        __tlb_flush_local();
}
run on CPU1.  That does
static inline void set_user_asce(struct mm_struct *mm)
{
        S390_lowcore.user_asce = mm->context.asce;
OK, user page table address updated...
        __ctl_load(S390_lowcore.user_asce, 1, 1);
... and control register 1 set to it.
        clear_cpu_flag(CIF_ASCE_PRIMARY);
}

IPI is run in home space mode, so it's fine - insns are fetched
using c13, which always points to kernel page table.  But as soon
as we return from the interrupt, previous PSW is restored, putting
CPU1 back into secondary space mode, at which point we no longer
get the kernel instructions from the kernel mapping.

The fix is to only fixup the control registers that are currently in use
for user processes during the page table update.  We must also disable
interrupts in enable_sacf_uaccess to synchronize the cr and
thread.mm_segment updates against the on_each-cpu.

Fixes: 0aaba41b58bc ("s390: remove all code using the access register mode")
Cc: stable@vger.kernel.org # 4.15+
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
References: CVE-2020-11884
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-29 16:31:35 +02:00
Sean Christopherson
4cfcc37091 KVM: s390: Return last valid slot if approx index is out-of-bounds
commit 97daa028f3f621adff2c4f7b15fe0874e5b5bd6c upstream.

Return the index of the last valid slot from gfn_to_memslot_approx() if
its binary search loop yielded an out-of-bounds index.  The index can
be out-of-bounds if the specified gfn is less than the base of the
lowest memslot (which is also the last valid memslot).

Note, the sole caller, kvm_s390_get_cmma(), ensures used_slots is
non-zero.

Fixes: afdad61615cc3 ("KVM: s390: Fix storage attributes migration with memory slots")
Cc: stable@vger.kernel.org # 4.19.x: 0774a964ef56: KVM: Fix out of range accesses to memslots
Cc: stable@vger.kernel.org # 4.19.x
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200408064059.8957-3-sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-29 16:31:30 +02:00
David Hildenbrand
41228f464f KVM: s390: vsie: Fix possible race when shadowing region 3 tables
[ Upstream commit 1493e0f944f3c319d11e067c185c904d01c17ae5 ]

We have to properly retry again by returning -EINVAL immediately in case
somebody else instantiated the table concurrently. We missed to add the
goto in this function only. The code now matches the other, similar
shadowing functions.

We are overwriting an existing region 2 table entry. All allocated pages
are added to the crst_list to be freed later, so they are not lost
forever. However, when unshadowing the region 2 table, we wouldn't trigger
unshadowing of the original shadowed region 3 table that we replaced. It
would get unshadowed when the original region 3 table is modified. As it's
not connected to the page table hierarchy anymore, it's not going to get
used anymore. However, for a limited time, this page table will stick
around, so it's in some sense a temporary memory leak.

Identified by manual code inspection. I don't think this classifies as
stable material.

Fixes: 998f637cc4b9 ("s390/mm: avoid races on region/segment/page table shadowing")
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200403153050.20569-4-david@redhat.com
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-23 10:30:20 +02:00
Thomas Richter
60cb788694 s390/cpum_sf: Fix wrong page count in error message
[ Upstream commit 4141b6a5e9f171325effc36a22eb92bf961e7a5c ]

When perf record -e SF_CYCLES_BASIC_DIAG runs with very high
frequency, the samples arrive faster than the perf process can
save them to file. Eventually, for longer running processes, this
leads to the siutation where the trace buffers allocated by perf
slowly fills up. At one point the auxiliary trace buffer is full
and  the CPU Measurement sampling facility is turned off. Furthermore
a warning is printed to the kernel log buffer:

cpum_sf: The AUX buffer with 0 pages for the diagnostic-sampling
	mode is full

The number of allocated pages for the auxiliary trace buffer is shown
as zero pages. That is wrong.

Fix this by saving the number of allocated pages before entering the
work loop in the interrupt handler. When the interrupt handler processes
the samples, it may detect the buffer full condition and stop sampling,
reducing the buffer size to zero.
Print the correct value in the error message:

cpum_sf: The AUX buffer with 256 pages for the diagnostic-sampling
	mode is full

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-23 10:30:18 +02:00
Alexander Gordeev
ffc059b5b9 s390/cpuinfo: fix wrong output when CPU0 is offline
[ Upstream commit 872f27103874a73783aeff2aac2b41a489f67d7c ]

/proc/cpuinfo should not print information about CPU 0 when it is offline.

Fixes: 281eaa8cb67c ("s390/cpuinfo: simplify locking and skip offline cpus early")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
[heiko.carstens@de.ibm.com: shortened commit message]
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-23 10:30:18 +02:00
Michael Mueller
e68129e681 s390/diag: fix display of diagnose call statistics
commit 6c7c851f1b666a8a455678a0b480b9162de86052 upstream.

Show the full diag statistic table and not just parts of it.

The issue surfaced in a KVM guest with a number of vcpus
defined smaller than NR_DIAG_STAT.

Fixes: 1ec2772e0c3c ("s390/diag: add a statistic for diagnose calls")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Mueller <mimu@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-17 10:48:52 +02:00
David Hildenbrand
de2ac8a719 KVM: s390: vsie: Fix delivery of addressing exceptions
commit 4d4cee96fb7a3cc53702a9be8299bf525be4ee98 upstream.

Whenever we get an -EFAULT, we failed to read in guest 2 physical
address space. Such addressing exceptions are reported via a program
intercept to the nested hypervisor.

We faked the intercept, we have to return to guest 2. Instead, right
now we would be returning -EFAULT from the intercept handler, eventually
crashing the VM.
the correct thing to do is to return 1 as rc == 1 is the internal
representation of "we have to go back into g2".

Addressing exceptions can only happen if the g2->g3 page tables
reference invalid g2 addresses (say, either a table or the final page is
not accessible - so something that basically never happens in sane
environments.

Identified by manual code inspection.

Fixes: a3508fbe9dc6 ("KVM: s390: vsie: initial support for nested virtualization")
Cc: <stable@vger.kernel.org> # v4.8+
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200403153050.20569-3-david@redhat.com
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
[borntraeger@de.ibm.com: fix patch description]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-17 10:48:48 +02:00
David Hildenbrand
50a59d2df7 KVM: s390: vsie: Fix region 1 ASCE sanity shadow address checks
commit a1d032a49522cb5368e5dfb945a85899b4c74f65 upstream.

In case we have a region 1 the following calculation
(31 + ((gmap->asce & _ASCE_TYPE_MASK) >> 2)*11)
results in 64. As shifts beyond the size are undefined the compiler is
free to use instructions like sllg. sllg will only use 6 bits of the
shift value (here 64) resulting in no shift at all. That means that ALL
addresses will be rejected.

The can result in endless loops, e.g. when prefix cannot get mapped.

Fixes: 4be130a08420 ("s390/mm: add shadow gmap support")
Tested-by: Janosch Frank <frankja@linux.ibm.com>
Reported-by: Janosch Frank <frankja@linux.ibm.com>
Cc: <stable@vger.kernel.org> # v4.8+
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200403153050.20569-2-david@redhat.com
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
[borntraeger@de.ibm.com: fix patch description, remove WARN_ON_ONCE]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-17 10:48:47 +02:00
Julian Wiedmann
9623c8ae73 s390/qdio: fill SL with absolute addresses
[ Upstream commit e9091ffd6a0aaced111b5d6ead5eaab5cd7101bc ]

As the comment says, sl->sbal holds an absolute address. qeth currently
solves this through wild casting, while zfcp doesn't care.

Handle this properly in the code that actually builds the SL.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Steffen Maier <maier@linux.ibm.com> [for qdio]
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-03-11 14:14:54 +01:00
Masahiro Yamada
b696f79fd1 s390: make 'install' not depend on vmlinux
[ Upstream commit 94e90f727f7424d827256023cace829cad6896f4 ]

For the same reason as commit 19514fc665ff ("arm, kbuild: make "make
install" not depend on vmlinux"), the install targets should never
trigger the rebuild of the kernel.

The variable, CONFIGURE, is not set by anyone. Remove it as well.

Link: https://lkml.kernel.org/r/20200216144829.27023-1-masahiroy@kernel.org
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-03-11 14:14:53 +01:00
Nathan Chancellor
8541452acb s390/mm: Explicitly compare PAGE_DEFAULT_KEY against zero in storage_key_init_range
commit 380324734956c64cd060e1db4304f3117ac15809 upstream.

Clang warns:

 In file included from ../arch/s390/purgatory/purgatory.c:10:
 In file included from ../include/linux/kexec.h:18:
 In file included from ../include/linux/crash_core.h:6:
 In file included from ../include/linux/elfcore.h:5:
 In file included from ../include/linux/user.h:1:
 In file included from ../arch/s390/include/asm/user.h:11:
 ../arch/s390/include/asm/page.h:45:6: warning: converting the result of
 '<<' to a boolean always evaluates to false
 [-Wtautological-constant-compare]
         if (PAGE_DEFAULT_KEY)
            ^
 ../arch/s390/include/asm/page.h:23:44: note: expanded from macro
 'PAGE_DEFAULT_KEY'
 #define PAGE_DEFAULT_KEY        (PAGE_DEFAULT_ACC << 4)
                                                  ^
 1 warning generated.

Explicitly compare this against zero to silence the warning as it is
intended to be used in a boolean context.

Fixes: de3fa841e429 ("s390/mm: fix compile for PAGE_DEFAULT_KEY != 0")
Link: https://github.com/ClangBuiltLinux/linux/issues/860
Link: https://lkml.kernel.org/r/20200214064207.10381-1-natechancellor@gmail.com
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-28 16:39:00 +01:00
Vasily Gorbik
149412daa2 s390/ftrace: generate traced function stack frame
[ Upstream commit 45f7a0da600d3c409b5ad8d5ddddacd98ddc8840 ]

Currently backtrace from ftraced function does not contain ftraced
function itself. e.g. for "path_openat":

arch_stack_walk+0x15c/0x2d8
stack_trace_save+0x50/0x68
stack_trace_call+0x15e/0x3d8
ftrace_graph_caller+0x0/0x1c <-- ftrace code
do_filp_open+0x7c/0xe8 <-- ftraced function caller
do_open_execat+0x76/0x1b8
open_exec+0x52/0x78
load_elf_binary+0x180/0x1160
search_binary_handler+0x8e/0x288
load_script+0x2a8/0x2b8
search_binary_handler+0x8e/0x288
__do_execve_file.isra.39+0x6fa/0xb40
__s390x_sys_execve+0x56/0x68
system_call+0xdc/0x2d8

Ftraced function is expected in the backtrace by ftrace kselftests, which
are now failing. It would also be nice to have it for clarity reasons.

"ftrace_caller" itself is called without stack frame allocated for it
and does not store its caller (ftraced function). Instead it simply
allocates a stack frame for "ftrace_trace_function" and sets backchain
to point to ftraced function stack frame (which contains ftraced function
caller in saved r14).

To fix this issue make "ftrace_caller" allocate a stack frame
for itself just to store ftraced function for the stack unwinder.
As a result backtrace looks like the following:

arch_stack_walk+0x15c/0x2d8
stack_trace_save+0x50/0x68
stack_trace_call+0x15e/0x3d8
ftrace_graph_caller+0x0/0x1c <-- ftrace code
path_openat+0x6/0xd60  <-- ftraced function
do_filp_open+0x7c/0xe8 <-- ftraced function caller
do_open_execat+0x76/0x1b8
open_exec+0x52/0x78
load_elf_binary+0x180/0x1160
search_binary_handler+0x8e/0x288
load_script+0x2a8/0x2b8
search_binary_handler+0x8e/0x288
__do_execve_file.isra.39+0x6fa/0xb40
__s390x_sys_execve+0x56/0x68
system_call+0xdc/0x2d8

Reported-by: Sven Schnelle <sven.schnelle@ibm.com>
Tested-by: Sven Schnelle <sven.schnelle@ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-24 08:34:50 +01:00
Vasily Gorbik
29a8e429ba s390: adjust -mpacked-stack support check for clang 10
[ Upstream commit 253b3c4b2920e07ce9e2b18800b9b65245e2fafa ]

clang 10 introduces -mpacked-stack compiler option implementation. At the
same time currently it does not support a combination of -mpacked-stack
and -mbackchain. This leads to the following build error:

clang: error: unsupported option '-mpacked-stack with -mbackchain' for
target 's390x-ibm-linux'

If/when clang adds support for a combination of -mpacked-stack and
-mbackchain it would also require -msoft-float (like gcc does). According
to Ulrich Weigand "stack slot assigned to the kernel backchain overlaps
the stack slot assigned to the FPR varargs (both are required to be
placed immediately after the saved r15 slot if present)."

Extend -mpacked-stack compiler option support check to include all 3
options -mpacked-stack -mbackchain -msoft-float which must present to
support -mpacked-stack with -mbackchain.

Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-24 08:34:50 +01:00