linux-stable.git/arch, branch v4.19.249

s390/mm: use non-quiescing sske for KVM switch to keyed guest

2022-06-25T09:49:17+00:00

commit 3ae11dbcfac906a8c3a480e98660a823130dc16a upstream.

The switch to a keyed guest does not require a classic sske as the other
guest CPUs are not accessing the key before the switch is complete.
By using the NQ SSKE things are faster especially with multiple guests.

Signed-off-by: Christian Borntraeger 
Suggested-by: Janis Schoetterl-Glausch 
Reviewed-by: Claudio Imbrenda 
Link: https://lore.kernel.org/r/20220530092706.11637-3-borntraeger@linux.ibm.com
Signed-off-by: Christian Borntraeger 
Signed-off-by: Heiko Carstens 
Signed-off-by: Greg Kroah-Hartman

powerpc/mm: Switch obsolete dssall to .long

2022-06-25T09:49:17+00:00

commit d51f86cfd8e378d4907958db77da3074f6dce3ba upstream.

The dssall ("Data Stream Stop All") instruction is obsolete altogether
with other Data Cache Instructions since ISA 2.03 (year 2006).

LLVM IAS does not support it but PPC970 seems to be using it.
This switches dssall to .long as there is no much point in fixing LLVM.

Signed-off-by: Alexey Kardashevskiy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20211221055904.555763-6-aik@ozlabs.ru
[sudip: adjust context]
Signed-off-by: Sudip Mukherjee 
Signed-off-by: Greg Kroah-Hartman

RISC-V: fix barrier() use in

2022-06-25T09:49:17+00:00

commit 30aca1bacb398dec6c1ed5eeca33f355bd7b6203 upstream.

riscv's  uses barrier() so it should include


Fixes this build error:
  CC [M]  drivers/net/ethernet/emulex/benet/be_main.o
In file included from ./include/vdso/processor.h:10,
                 from ./arch/riscv/include/asm/processor.h:11,
                 from ./include/linux/prefetch.h:15,
                 from drivers/net/ethernet/emulex/benet/be_main.c:14:
./arch/riscv/include/asm/vdso/processor.h: In function 'cpu_relax':
./arch/riscv/include/asm/vdso/processor.h:14:2: error: implicit declaration of function 'barrier' [-Werror=implicit-function-declaration]
   14 |  barrier();

This happens with a total of 5 networking drivers -- they all use
.

rv64 allmodconfig now builds cleanly after this patch.

Fixes fallout from:
815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually exclusive")

Fixes: ad5d1122b82f ("riscv: use vDSO common flow to reduce the latency of the time-related functions")
Reported-by: Andreas Schwab 
Signed-off-by: Randy Dunlap 
Acked-by: Arvind Sankar 
Signed-off-by: Palmer Dabbelt 
Reviewed-by: Nick Desaulniers 
Signed-off-by: Palmer Dabbelt 
[sudip: change in old path]
Signed-off-by: Sudip Mukherjee 
Signed-off-by: Greg Kroah-Hartman

arm64: ftrace: fix branch range checks

2022-06-25T09:49:16+00:00

[ Upstream commit 3eefdf9d1e406f3da47470b2854347009ffcb6fa ]

The branch range checks in ftrace_make_call() and ftrace_make_nop() are
incorrect, erroneously permitting a forwards branch of 128M and
erroneously rejecting a backwards branch of 128M.

This is because both functions calculate the offset backwards,
calculating the offset *from* the target *to* the branch, rather than
the other way around as the later comparisons expect.

If an out-of-range branch were erroeously permitted, this would later be
rejected by aarch64_insn_gen_branch_imm() as branch_imm_common() checks
the bounds correctly, resulting in warnings and the placement of a BRK
instruction. Note that this can only happen for a forwards branch of
exactly 128M, and so the caller would need to be exactly 128M bytes
below the relevant ftrace trampoline.

If an in-range branch were erroeously rejected, then:

* For modules when CONFIG_ARM64_MODULE_PLTS=y, this would result in the
  use of a PLT entry, which is benign.

  Note that this is the common case, as this is selected by
  CONFIG_RANDOMIZE_BASE (and therefore RANDOMIZE_MODULE_REGION_FULL),
  which distributions typically seelct. This is also selected by
  CONFIG_ARM64_ERRATUM_843419.

* For modules when CONFIG_ARM64_MODULE_PLTS=n, this would result in
  internal ftrace failures.

* For core kernel text, this would result in internal ftrace failues.

  Note that for this to happen, the kernel text would need to be at
  least 128M bytes in size, and typical configurations are smaller tha
  this.

Fix this by calculating the offset *from* the branch *to* the target in
both functions.

Fixes: f8af0b364e24 ("arm64: ftrace: don't validate branch via PLT in ftrace_make_nop()")
Fixes: e71a4e1bebaf ("arm64: ftrace: add support for far branches to dynamic ftrace")
Signed-off-by: Mark Rutland 
Cc: Ard Biesheuvel 
Cc: Will Deacon 
Tested-by: "Ivan T. Ivanov" 
Reviewed-by: Chengming Zhou 
Reviewed-by: Ard Biesheuvel 
Link: https://lore.kernel.org/r/20220614080944.1349146-2-mark.rutland@arm.com
Signed-off-by: Catalin Marinas 
Signed-off-by: Sasha Levin

powerpc/kasan: Silence KASAN warnings in __get_wchan()

2022-06-25T09:49:13+00:00

[ Upstream commit a1b29ba2f2c171b9bea73be993bfdf0a62d37d15 ]

The following KASAN warning was reported in our kernel.

  BUG: KASAN: stack-out-of-bounds in get_wchan+0x188/0x250
  Read of size 4 at addr d216f958 by task ps/14437

  CPU: 3 PID: 14437 Comm: ps Tainted: G           O      5.10.0 #1
  Call Trace:
  [daa63858] [c0654348] dump_stack+0x9c/0xe4 (unreliable)
  [daa63888] [c035cf0c] print_address_description.constprop.3+0x8c/0x570
  [daa63908] [c035d6bc] kasan_report+0x1ac/0x218
  [daa63948] [c00496e8] get_wchan+0x188/0x250
  [daa63978] [c0461ec8] do_task_stat+0xce8/0xe60
  [daa63b98] [c0455ac8] proc_single_show+0x98/0x170
  [daa63bc8] [c03cab8c] seq_read_iter+0x1ec/0x900
  [daa63c38] [c03cb47c] seq_read+0x1dc/0x290
  [daa63d68] [c037fc94] vfs_read+0x164/0x510
  [daa63ea8] [c03808e4] ksys_read+0x144/0x1d0
  [daa63f38] [c005b1dc] ret_from_syscall+0x0/0x38
  --- interrupt: c00 at 0x8fa8f4
      LR = 0x8fa8cc

  The buggy address belongs to the page:
  page:98ebcdd2 refcount:0 mapcount:0 mapping:00000000 index:0x2 pfn:0x1216f
  flags: 0x0()
  raw: 00000000 00000000 01010122 00000000 00000002 00000000 ffffffff 00000000
  raw: 00000000
  page dumped because: kasan: bad access detected

  Memory state around the buggy address:
   d216f800: 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00 00 00
   d216f880: f2 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  >d216f900: 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00
                                            ^
   d216f980: f2 f2 f2 f2 f2 f2 f2 00 00 00 00 00 00 00 00 00
   d216fa00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

After looking into this issue, I find the buggy address belongs
to the task stack region. It seems KASAN has something wrong.
I look into the code of __get_wchan in x86 architecture and
find the same issue has been resolved by the commit
f7d27c35ddff ("x86/mm, kasan: Silence KASAN warnings in get_wchan()").
The solution could be applied to powerpc architecture too.

As Andrey Ryabinin said, get_wchan() is racy by design, it may
access volatile stack of running task, thus it may access
redzone in a stack frame and cause KASAN to warn about this.

Use READ_ONCE_NOCHECK() to silence these warnings.

Reported-by: Wanming Hu 
Signed-off-by: He Ying 
Signed-off-by: Chen Jingwen 
Reviewed-by: Kees Cook 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220121014418.155675-1-heying24@huawei.com
Signed-off-by: Sasha Levin

xtensa: use fallback for random_get_entropy() instead of zero

2022-06-25T09:49:10+00:00

commit e10e2f58030c5c211d49042a8c2a1b93d40b2ffb upstream.

In the event that random_get_entropy() can't access a cycle counter or
similar, falling back to returning 0 is really not the best we can do.
Instead, at least calling random_get_entropy_fallback() would be
preferable, because that always needs to return _something_, even
falling back to jiffies eventually. It's not as though
random_get_entropy_fallback() is super high precision or guaranteed to
be entropic, but basically anything that's not zero all the time is
better than returning zero all the time.

This is accomplished by just including the asm-generic code like on
other architectures, which means we can get rid of the empty stub
function here.

Cc: Thomas Gleixner 
Cc: Arnd Bergmann 
Acked-by: Max Filippov 
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Greg Kroah-Hartman

sparc: use fallback for random_get_entropy() instead of zero

2022-06-25T09:49:10+00:00

commit ac9756c79797bb98972736b13cfb239fd2cffb79 upstream.

In the event that random_get_entropy() can't access a cycle counter or
similar, falling back to returning 0 is really not the best we can do.
Instead, at least calling random_get_entropy_fallback() would be
preferable, because that always needs to return _something_, even
falling back to jiffies eventually. It's not as though
random_get_entropy_fallback() is super high precision or guaranteed to
be entropic, but basically anything that's not zero all the time is
better than returning zero all the time.

This is accomplished by just including the asm-generic code like on
other architectures, which means we can get rid of the empty stub
function here.

Cc: Thomas Gleixner 
Cc: Arnd Bergmann 
Cc: David S. Miller 
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Greg Kroah-Hartman

um: use fallback for random_get_entropy() instead of zero

2022-06-25T09:49:10+00:00

commit 9f13fb0cd11ed2327abff69f6501a2c124c88b5a upstream.

In the event that random_get_entropy() can't access a cycle counter or
similar, falling back to returning 0 is really not the best we can do.
Instead, at least calling random_get_entropy_fallback() would be
preferable, because that always needs to return _something_, even
falling back to jiffies eventually. It's not as though
random_get_entropy_fallback() is super high precision or guaranteed to
be entropic, but basically anything that's not zero all the time is
better than returning zero all the time.

This is accomplished by just including the asm-generic code like on
other architectures, which means we can get rid of the empty stub
function here.

Cc: Thomas Gleixner 
Cc: Arnd Bergmann 
Cc: Richard Weinberger 
Cc: Anton Ivanov 
Acked-by: Johannes Berg 
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Greg Kroah-Hartman

x86/tsc: Use fallback for random_get_entropy() instead of zero

2022-06-25T09:49:10+00:00

commit 3bd4abc07a267e6a8b33d7f8717136e18f921c53 upstream.

In the event that random_get_entropy() can't access a cycle counter or
similar, falling back to returning 0 is suboptimal. Instead, fallback
to calling random_get_entropy_fallback(), which isn't extremely high
precision or guaranteed to be entropic, but is certainly better than
returning zero all the time.

If CONFIG_X86_TSC=n, then it's possible for the kernel to run on systems
without RDTSC, such as 486 and certain 586, so the fallback code is only
required for that case.

As well, fix up both the new function and the get_cycles() function from
which it was derived to use cpu_feature_enabled() rather than
boot_cpu_has(), and use !IS_ENABLED() instead of #ifndef.

Signed-off-by: Jason A. Donenfeld 
Reviewed-by: Thomas Gleixner 
Cc: Thomas Gleixner 
Cc: Arnd Bergmann 
Cc: Borislav Petkov 
Cc: x86@kernel.org
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Greg Kroah-Hartman

nios2: use fallback for random_get_entropy() instead of zero

2022-06-25T09:49:10+00:00

commit c04e72700f2293013dab40208e809369378f224c upstream.

In the event that random_get_entropy() can't access a cycle counter or
similar, falling back to returning 0 is really not the best we can do.
Instead, at least calling random_get_entropy_fallback() would be
preferable, because that always needs to return _something_, even
falling back to jiffies eventually. It's not as though
random_get_entropy_fallback() is super high precision or guaranteed to
be entropic, but basically anything that's not zero all the time is
better than returning zero all the time.

Cc: Thomas Gleixner 
Cc: Arnd Bergmann 
Acked-by: Dinh Nguyen 
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Greg Kroah-Hartman