6831 Commits

Author SHA1 Message Date
Alexander Egorenkov
f1754f96ab s390/boot: fix use of expolines in the DMA code
commit 463f36c76fa4ec015c640ff63ccf52e7527abee0 upstream.

The DMA code section of the decompressor must be compiled with expolines
if Spectre V2 mitigation has been enabled for the decompressed kernel.
This is required because although the decompressor's image contains
the DMA code section, it is handed over to the decompressed kernel for use.

Because the DMA code is already slow w/o expolines, use expolines always
regardless whether the decompressed kernel is using them or not. This
simplifies the DMA code by dropping the conditional compilation of
expolines.

Fixes: bf72630130c2 ("s390: use proper expoline sections for .dma code")
Cc: <stable@vger.kernel.org> # 5.2
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-28 13:30:58 +02:00
Vasily Gorbik
8eb521d192 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 13:30:58 +02:00
Colin Ian King
58259e8b6e 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 13:30:55 +02:00
Heiko Carstens
06d8a7eb58 s390: introduce proper type handling call_on_stack() macro
[ Upstream commit 41d71fe59cce41237f24f3b7bdc1b414069a34ed ]

The existing CALL_ON_STACK() macro allows for subtle bugs:

- There is no type checking of the function that is being called. That
  is: missing or too many arguments do not cause any compile error or
  warning. The same is true if the return type of the called function
  changes. This can lead to quite random bugs.

- Sign and zero extension of arguments is missing. Given that the s390
  C ABI requires that the caller of a function performs proper sign
  and zero extension this can also lead to subtle bugs.

- If arguments to the CALL_ON_STACK() macros contain functions calls
  register corruption can happen due to register asm constructs being
  used.

Therefore introduce a new call_on_stack() macro which is supposed to
fix all these problems.

Reviewed-by: Sven Schnelle <svens@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>
2021-07-25 14:35:13 +02:00
Heiko Carstens
5f5c1e6833 s390/mem_detect: fix tprot() program check new psw handling
[ Upstream commit da9057576785aaab52e706e76c0475c85b77ec14 ]

The tprot() inline asm temporarily changes the program check new psw
to redirect a potential program check on the diag instruction.
Restoring of the program check new psw is done in C code behind the
inline asm.

This can be problematic, especially if the function is inlined, since
the compiler can reorder instructions in such a way that a different
instruction, which may result in a program check, might be executed
before the program check new psw has been restored.

To avoid such a scenario move restoring into the inline asm. For
consistency reasons move also saving of the original program check new
psw into the inline asm.

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>
2021-07-20 16:10:45 +02:00
Heiko Carstens
8a3adb4292 s390/mem_detect: fix diag260() program check new psw handling
[ Upstream commit 86807f348f418a84970eebb8f9912a7eea16b497 ]

The __diag260() inline asm temporarily changes the program check new
psw to redirect a potential program check on the diag instruction.
Restoring of the program check new psw is done in C code behind the
inline asm.

This can be problematic, especially if the function is inlined, since
the compiler can reorder instructions in such a way that a different
instruction, which may result in a program check, might be executed
before the program check new psw has been restored.

To avoid such a scenario move restoring into the inline asm. For
consistency reasons move also saving of the original program check new
psw into the inline asm.

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>
2021-07-20 16:10:44 +02:00
Heiko Carstens
e8df008548 s390/ipl_parm: fix program check new psw handling
[ Upstream commit 88c2510cecb7e2b518e3c4fdf3cf0e13ebe9377c ]

The __diag308() inline asm temporarily changes the program check new
psw to redirect a potential program check on the diag instruction.
Restoring of the program check new psw is done in C code behind the
inline asm.

This can be problematic, especially if the function is inlined, since
the compiler can reorder instructions in such a way that a different
instruction, which may result in a program check, might be executed
before the program check new psw has been restored.

To avoid such a scenario move restoring into the inline asm. For
consistency reasons move also saving of the original program check new
psw into the inline asm.

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>
2021-07-20 16:10:44 +02:00
Heiko Carstens
5176a4d1c4 s390/processor: always inline stap() and __load_psw_mask()
[ Upstream commit 9c9a915afd90f7534c16a71d1cd44b58596fddf3 ]

s390 is the only architecture which makes use of the __no_kasan_or_inline
attribute for two functions. Given that both stap() and __load_psw_mask()
are very small functions they can and should be always inlined anyway.

Therefore get rid of __no_kasan_or_inline and always inline these
functions.

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>
2021-07-20 16:10:44 +02:00
Valentin Vidic
f0bca3fbf1 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 16:10:43 +02:00
Randy Dunlap
1e38d79d0b 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>
2021-07-14 16:53:42 +02:00
Heiko Carstens
fc31fb6f36 KVM: s390: get rid of register asm usage
[ Upstream commit 4fa3b91bdee1b08348c82660668ca0ca34e271ad ]

Using register asm statements has been proven to be very error prone,
especially when using code instrumentation where gcc may add function
calls, which clobbers register contents in an unexpected way.

Therefore get rid of register asm statements in kvm code, even though
there is currently nothing wrong with them. This way we know for sure
that this bug class won't be introduced here.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20210621140356.1210771-1-hca@linux.ibm.com
[borntraeger@de.ibm.com: checkpatch strict fix]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14 16:53:15 +02:00
Heiko Carstens
58356f448b s390/stack: fix possible register corruption with stack switch helper
commit 67147e96a332b56c7206238162771d82467f86c0 upstream.

The CALL_ON_STACK macro is used to call a C function from inline
assembly, and therefore must consider the C ABI, which says that only
registers 6-13, and 15 are non-volatile (restored by the called
function).

The inline assembly incorrectly marks all registers used to pass
parameters to the called function as read-only input operands, instead
of operands that are read and written to. This might result in
register corruption depending on usage, compiler, and compile options.

Fix this by marking all operands used to pass parameters as read/write
operands. To keep the code simple even register 6, if used, is marked
as read-write operand.

Fixes: ff340d2472ec ("s390: add stack switch helper")
Cc: <stable@kernel.org> # 4.20
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-11 12:52:07 +02:00
Claudio Imbrenda
3582644257 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>
2021-05-14 09:44:15 +02:00
David Hildenbrand
45a3ae26fc s390: fix detection of vector enhancements facility 1 vs. vector packed decimal facility
commit b208108638c4bd3215792415944467c36f5dfd97 upstream.

The PoP documents:
	134: The vector packed decimal facility is installed in the
	     z/Architecture architectural mode. When bit 134 is
	     one, bit 129 is also one.
	135: The vector enhancements facility 1 is installed in
	     the z/Architecture architectural mode. When bit 135
	     is one, bit 129 is also one.

Looks like we confuse the vector enhancements facility 1 ("EXT") with the
Vector packed decimal facility ("BCD"). Let's fix the facility checks.

Detected while working on QEMU/tcg z14 support and only unlocking
the vector enhancements facility 1, but not the vector packed decimal
facility.

Fixes: 2583b848cad0 ("s390: report new vector facilities")
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20210503121244.25232-1-david@redhat.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-14 09:44:15 +02:00
Heiko Carstens
9ea2c4fd1a 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>
2021-05-14 09:44:15 +02:00
Claudio Imbrenda
34a6d1d57c 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>
2021-05-14 09:44:15 +02:00
Harald Freudenberger
a65181cfd9 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>
2021-05-11 14:04:13 +02:00
Vasily Gorbik
b691331218 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>
2021-05-11 14:04:01 +02:00
Vasily Gorbik
78687d6a32 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 13:19:15 +02:00
Sven Schnelle
835c8d688e s390/ptrace: return -ENOSYS when invalid syscall is supplied
commit cd29fa798001075a554b978df3a64e6656c25794 upstream.

The current code returns the syscall number which an invalid
syscall number is supplied and tracing is enabled. This makes
the strace testsuite fail.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1895132
[krzysztof: adjusted the backport around missing ifdef CONFIG_SECCOMP,
 add Link and Fixes; apparently this should go with the referenced commit]
Fixes: 00332c16b160 ("s390/ptrace: pass invalid syscall numbers to tracing")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-28 13:19:14 +02:00
Alexander Gordeev
d3343a35d1 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 08:24:17 +02:00
Gerald Schaefer
34794bc0e7 s390/vtime: fix increased steal time accounting
commit d54cb7d54877d529bc1e0e1f47a3dd082f73add3 upstream.

Commit 152e9b8676c6e ("s390/vtime: steal time exponential moving average")
inadvertently changed the input value for account_steal_time() from
"cputime_to_nsecs(steal)" to just "steal", resulting in broken increased
steal time accounting.

Fix this by changing it back to "cputime_to_nsecs(steal)".

Fixes: 152e9b8676c6e ("s390/vtime: steal time exponential moving average")
Cc: <stable@vger.kernel.org> # 5.1
Reported-by: Sabine Forkel <sabine.forkel@de.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-24 11:26:35 +01:00
Heiko Carstens
508d56e2c5 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 17:03:45 +01:00
Heiko Carstens
8e6c8cfa9a s390/vtime: fix inline assembly clobber list
commit b29c5093820d333eef22f58cd04ec0d089059c39 upstream.

The stck/stckf instruction used within the inline assembly within
do_account_vtime() changes the condition code. This is not reflected
with the clobber list, and therefore might result in incorrect code
generation.

It seems unlikely that the compiler could generate incorrect code
considering the surrounding C code, but it must still be fixed.

Cc: <stable@vger.kernel.org>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-04 10:26:50 +01:00
Philipp Rudo
3038bbd1bb 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 11:51:34 +01:00
Sven Schnelle
c185f13918 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 11:51:34 +01:00
Thomas Richter
e6e76a26fd 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 13:29:23 +01:00
Qian Cai
4d6f536e34 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 19:20:24 +01:00
Sven Schnelle
551bf7c4bc 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 11:43:30 +01:00
Vasily Gorbik
fb9b18150e s390/startup: avoid save_area_sync overflow
[ Upstream commit 2835c2ea95d50625108e47a459e1a47f6be836ce ]

Currently we overflow save_area_sync and write over
save_area_async. Although this is not a real problem make
startup_pgm_check_handler consistent with late pgm check handler and
store [%r0,%r7] directly into gpregs_save_area.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-11-05 11:43:14 +01:00
Vasily Gorbik
4f5260ee0c mm/gup: fix gup_fast with dynamic page table folding
commit d3f7b1bb204099f2f7306318896223e8599bb6a2 upstream.

Currently to make sure that every page table entry is read just once
gup_fast walks perform READ_ONCE and pass pXd value down to the next
gup_pXd_range function by value e.g.:

  static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end,
                           unsigned int flags, struct page **pages, int *nr)
  ...
          pudp = pud_offset(&p4d, addr);

This function passes a reference on that local value copy to pXd_offset,
and might get the very same pointer in return.  This happens when the
level is folded (on most arches), and that pointer should not be
iterated.

On s390 due to the fact that each task might have different 5,4 or
3-level address translation and hence different levels folded the logic
is more complex and non-iteratable pointer to a local copy leads to
severe problems.

Here is an example of what happens with gup_fast on s390, for a task
with 3-level paging, crossing a 2 GB pud boundary:

  // addr = 0x1007ffff000, end = 0x10080001000
  static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end,
                           unsigned int flags, struct page **pages, int *nr)
  {
        unsigned long next;
        pud_t *pudp;

        // pud_offset returns &p4d itself (a pointer to a value on stack)
        pudp = pud_offset(&p4d, addr);
        do {
                // on second iteratation reading "random" stack value
                pud_t pud = READ_ONCE(*pudp);

                // next = 0x10080000000, due to PUD_SIZE/MASK != PGDIR_SIZE/MASK on s390
                next = pud_addr_end(addr, end);
                ...
        } while (pudp++, addr = next, addr != end); // pudp++ iterating over stack

        return 1;
  }

This happens since s390 moved to common gup code with commit
d1874a0c2805 ("s390/mm: make the pxd_offset functions more robust") and
commit 1a42010cdc26 ("s390/mm: convert to the generic
get_user_pages_fast code").

s390 tried to mimic static level folding by changing pXd_offset
primitives to always calculate top level page table offset in pgd_offset
and just return the value passed when pXd_offset has to act as folded.

What is crucial for gup_fast and what has been overlooked is that
PxD_SIZE/MASK and thus pXd_addr_end should also change correspondingly.
And the latter is not possible with dynamic folding.

To fix the issue in addition to pXd values pass original pXdp pointers
down to gup_pXd_range functions.  And introduce pXd_offset_lockless
helpers, which take an additional pXd entry value parameter.  This has
already been discussed in

  https://lkml.kernel.org/r/20190418100218.0a4afd51@mschwideX1

Fixes: 1a42010cdc26 ("s390/mm: convert to the generic get_user_pages_fast code")
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: <stable@vger.kernel.org>	[5.2+]
Link: https://lkml.kernel.org/r/patch.git-943f1e5dcff2.your-ad-here.call-01599856292-ext-8676@work.hours
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-01 13:18:24 +02:00
Ilya Leoshkevich
43d750a099 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 13:18:14 +02:00
afzal mohammed
fc1d08a202 s390/irq: replace setup_irq() by request_irq()
[ Upstream commit 8719b6d29d2851fa84c4074bb2e5adc022911ab8 ]

request_irq() is preferred over setup_irq(). Invocations of setup_irq()
occur after memory allocators are ready.

Per tglx[1], setup_irq() existed in olden days when allocators were not
ready by the time early interrupts were initialized.

Hence replace setup_irq() by request_irq().

[1] https://lkml.kernel.org/r/alpine.DEB.2.20.1710191609480.1971@nanos

Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com>
Message-Id: <20200304005049.5291-1-afzal.mohd.ma@gmail.com>
[heiko.carstens@de.ibm.com: replace pr_err with panic]
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>
2020-10-01 13:17:40 +02:00
Thomas Richter
4f726a2afb 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 13:17:28 +02:00
Vasily Gorbik
a04223019c s390: avoid misusing CALL_ON_STACK for task stack setup
[ Upstream commit 7bcaad1f9fac889f5fcd1a383acf7e00d006da41 ]

CALL_ON_STACK is intended to be used for temporary stack switching with
potential return to the caller.

When CALL_ON_STACK is misused to switch from nodat stack to task stack
back_chain information would later lead stack unwinder from task stack into
(per cpu) nodat stack which is reused for other purposes. This would
yield confusing unwinding result or errors.

To avoid that introduce CALL_ON_STACK_NORETURN to be used instead. It
makes sure that back_chain is zeroed and unwinder finishes gracefully
ending up at task pt_regs.

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>
2020-10-01 13:17:22 +02:00
Sven Schnelle
29bade8e2f 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 19:12:22 +02:00
Sasha Levin
a0cfda9cb3 s390/numa: set node distance to LOCAL_DISTANCE
[ Upstream commit 535e4fc623fab2e09a0653fc3a3e17f382ad0251 ]

The node distance is hardcoded to 0, which causes a trouble
for some user-level applications. In particular, "libnuma"
expects the distance of a node to itself as LOCAL_DISTANCE.
This update removes the offending node distance override.

Cc: <stable@vger.kernel.org> # 4.4
Fixes: 3a368f742da1 ("s390/numa: add core infrastructure")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-09-03 11:26:50 +02:00
Heiko Carstens
e9849a60fa 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 10:41:02 +02:00
Heiko Carstens
d35f24bc56 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 10:41:02 +02:00
Gerald Schaefer
4db28111b2 s390/gmap: improve THP splitting
commit ba925fa35057a062ac98c3e8138b013ce4ce351c upstream.

During s390_enable_sie(), we need to take care of splitting all qemu user
process THP mappings. This is currently done with follow_page(FOLL_SPLIT),
by simply iterating over all vma ranges, with PAGE_SIZE increment.

This logic is sub-optimal and can result in a lot of unnecessary overhead,
especially when using qemu and ASAN with large shadow map. Ilya reported
significant system slow-down with one CPU busy for a long time and overall
unresponsiveness.

Fix this by using walk_page_vma() and directly calling split_huge_pmd()
only for present pmds, which greatly reduces overhead.

Cc: <stable@vger.kernel.org> # v5.4+
Reported-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-08-19 08:16:29 +02:00
Vasily Gorbik
1a70857590 s390/maccess: add no DAT mode to kernel_write
[ Upstream commit d6df52e9996dcc2062c3d9c9123288468bb95b52 ]

To be able to patch kernel code before paging is initialized do plain
memcpy if DAT is off. This is required to enable early jump label
initialization.

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 08:16:48 +02:00
Josh Poimboeuf
627d15eecb s390: Change s390_kernel_write() return type to match memcpy()
[ Upstream commit cb2cceaefb4c4dc28fc27ff1f1b2d258bfc10353 ]

s390_kernel_write()'s function type is almost identical to memcpy().
Change its return type to "void *" so they can be used interchangeably.

Cc: linux-s390@vger.kernel.org
Cc: heiko.carstens@de.ibm.com
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> # s390
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-07-16 08:16:48 +02:00
Janosch Frank
2dfd182451 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 08:16:47 +02:00
Vasily Gorbik
0d62bc7e96 s390/setup: init jump labels before command line parsing
commit 95e61b1b5d6394b53d147c0fcbe2ae70fbe09446 upstream.

Command line parameters might set static keys. This is true for s390 at
least since commit 6471384af2a6 ("mm: security: introduce init_on_alloc=1
and init_on_free=1 boot options"). To avoid the following WARN:

static_key_enable_cpuslocked(): static key 'init_on_alloc+0x0/0x40' used
before call to jump_label_init()

call jump_label_init() just before parse_early_param().
jump_label_init() is safe to call multiple times (x86 does that), doesn't
do any memory allocations and hence should be safe to call that early.

Fixes: 6471384af2a6 ("mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options")
Cc: <stable@vger.kernel.org> # 5.3: d6df52e9996d: s390/maccess: add no DAT mode to kernel_write
Cc: <stable@vger.kernel.org> # 5.3
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-16 08:16:46 +02:00
Vasily Gorbik
9c732cccb0 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 08:16:35 +02:00
Christian Borntraeger
eb676bef02 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 08:16:32 +02:00
Christian Borntraeger
8f4aa3a6de 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 09:37:50 +02:00
Vincenzo Frascino
a9a3b33b20 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 15:37:05 -04:00
Nathan Chancellor
68a3cbc446 s390/vdso: Use $(LD) instead of $(CC) to link vDSO
[ Upstream commit 2b2a25845d534ac6d55086e35c033961fdd83a26 ]

Currently, the VDSO is being linked through $(CC). This does not match
how the rest of the kernel links objects, which is through the $(LD)
variable.

When clang is built in a default configuration, it first attempts to use
the target triple's default linker, which is just ld. However, the user
can override this through the CLANG_DEFAULT_LINKER cmake define so that
clang uses another linker by default, such as LLVM's own linker, ld.lld.
This can be useful to get more optimized links across various different
projects.

However, this is problematic for the s390 vDSO because ld.lld does not
have any s390 emulatiom support:

https://github.com/llvm/llvm-project/blob/llvmorg-10.0.1-rc1/lld/ELF/Driver.cpp#L132-L150

Thus, if a user is using a toolchain with ld.lld as the default, they
will see an error, even if they have specified ld.bfd through the LD
make variable:

$ make -j"$(nproc)" -s ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- LLVM=1 \
                       LD=s390x-linux-gnu-ld \
                       defconfig arch/s390/kernel/vdso64/
ld.lld: error: unknown emulation: elf64_s390
clang-11: error: linker command failed with exit code 1 (use -v to see invocation)

Normally, '-fuse-ld=bfd' could be used to get around this; however, this
can be fragile, depending on paths and variable naming. The cleaner
solution for the kernel is to take advantage of the fact that $(LD) can
be invoked directly, which bypasses the heuristics of $(CC) and respects
the user's choice. Similar changes have been done for ARM, ARM64, and
MIPS.

Link: https://lkml.kernel.org/r/20200602192523.32758-1-natechancellor@gmail.com
Link: https://github.com/ClangBuiltLinux/linux/issues/1041
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
[heiko.carstens@de.ibm.com: add --build-id flag]
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 15:37:05 -04:00
Sven Schnelle
7c17909a88 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 15:37:04 -04:00