linux-stable.git/include/asm-generic, branch v5.13.2

mm: define default MAX_PTRS_PER_* in include/pgtable.h

2021-07-14T15:06:38+00:00

[ Upstream commit c0f8aa4fa815daacb6eca52cae04820d6aecb7c2 ]

Commit c65e774fb3f6 ("x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable")
made PTRS_PER_P4D variable on x86 and introduced MAX_PTRS_PER_P4D as a
constant for cases which need a compile-time constant (e.g.  fixed-size
arrays).

powerpc likewise has boot-time selectable MMU features which can cause
other mm "constants" to vary.  For KASAN, we have some static
PTE/PMD/PUD/P4D arrays so we need compile-time maximums for all these
constants.  Extend the MAX_PTRS_PER_ idiom, and place default definitions
in include/pgtable.h.  These define MAX_PTRS_PER_x to be PTRS_PER_x unless
an architecture has defined MAX_PTRS_PER_x in its arch headers.

Clean up pgtable-nop4d.h and s390's MAX_PTRS_PER_P4D definitions while
we're at it: both can just pick up the default now.

Link: https://lkml.kernel.org/r/20210624034050.511391-4-dja@axtens.net
Signed-off-by: Daniel Axtens 
Acked-by: Andrey Konovalov 
Reviewed-by: Christophe Leroy 
Reviewed-by: Marco Elver 
Cc: Aneesh Kumar K.V 
Cc: Balbir Singh 
Cc: Alexander Potapenko 
Cc: Andrey Ryabinin 
Cc: Dmitry Vyukov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

sched/core: Initialize the idle task with preemption disabled

2021-07-14T15:06:21+00:00

[ Upstream commit f1a0a376ca0c4ef1fc3d24e3e502acbb5b795674 ]

As pointed out by commit

  de9b8f5dcbd9 ("sched: Fix crash trying to dequeue/enqueue the idle thread")

init_idle() can and will be invoked more than once on the same idle
task. At boot time, it is invoked for the boot CPU thread by
sched_init(). Then smp_init() creates the threads for all the secondary
CPUs and invokes init_idle() on them.

As the hotplug machinery brings the secondaries to life, it will issue
calls to idle_thread_get(), which itself invokes init_idle() yet again.
In this case it's invoked twice more per secondary: at _cpu_up(), and at
bringup_cpu().

Given smp_init() already initializes the idle tasks for all *possible*
CPUs, no further initialization should be required. Now, removing
init_idle() from idle_thread_get() exposes some interesting expectations
with regards to the idle task's preempt_count: the secondary startup always
issues a preempt_disable(), requiring some reset of the preempt count to 0
between hot-unplug and hotplug, which is currently served by
idle_thread_get() -> idle_init().

Given the idle task is supposed to have preemption disabled once and never
see it re-enabled, it seems that what we actually want is to initialize its
preempt_count to PREEMPT_DISABLED and leave it there. Do that, and remove
init_idle() from idle_thread_get().

Secondary startups were patched via coccinelle:

  @begone@
  @@

  -preempt_disable();
  ...
  cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);

Signed-off-by: Valentin Schneider 
Signed-off-by: Ingo Molnar 
Acked-by: Peter Zijlstra 
Link: https://lore.kernel.org/r/20210512094636.2958515-1-valentin.schneider@arm.com
Signed-off-by: Sasha Levin

vmlinux.lds.h: Avoid orphan section with !SMP

2021-06-02T19:43:55+00:00

With x86_64_defconfig and the following configs, there is an orphan
section warning:

CONFIG_SMP=n
CONFIG_AMD_MEM_ENCRYPT=y
CONFIG_HYPERVISOR_GUEST=y
CONFIG_KVM=y
CONFIG_PARAVIRT=y

ld: warning: orphan section `.data..decrypted' from `arch/x86/kernel/cpu/vmware.o' being placed in section `.data..decrypted'
ld: warning: orphan section `.data..decrypted' from `arch/x86/kernel/kvm.o' being placed in section `.data..decrypted'

These sections are created with DEFINE_PER_CPU_DECRYPTED, which
ultimately turns into __PCPU_ATTRS, which in turn has a section
attribute with a value of PER_CPU_BASE_SECTION + the section name. When
CONFIG_SMP is not set, the base section is .data and that is not
currently handled in any linker script.

Add .data..decrypted to PERCPU_DECRYPTED_SECTION, which is included in
PERCPU_INPUT -> PERCPU_SECTION, which is include in the x86 linker
script when either CONFIG_X86_64 or CONFIG_SMP is unset, taking care of
the warning.

Fixes: ac26963a1175 ("percpu: Introduce DEFINE_PER_CPU_DECRYPTED")
Link: https://github.com/ClangBuiltLinux/linux/issues/1360
Reported-by: kernel test robot 
Signed-off-by: Nathan Chancellor 
Tested-by: Nick Desaulniers  # build
Signed-off-by: Kees Cook 
Link: https://lore.kernel.org/r/20210506001410.1026691-1-nathan@kernel.org

mm: remove xlate_dev_kmem_ptr()

2021-05-07T07:26:34+00:00

Since /dev/kmem has been removed, let's remove the xlate_dev_kmem_ptr()
leftovers.

Link: https://lkml.kernel.org/r/20210324102351.6932-3-david@redhat.com
Signed-off-by: David Hildenbrand 
Acked-by: Geert Uytterhoeven 
Acked-by: Michal Hocko 
Cc: Linus Torvalds 
Cc: Greg Kroah-Hartman 
Cc: Richard Henderson 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Russell King 
Cc: Brian Cain 
Cc: Geert Uytterhoeven 
Cc: Thomas Bogendoerfer 
Cc: "James E.J. Bottomley" 
Cc: Helge Deller 
Cc: Michael Ellerman 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Heiko Carstens 
Cc: Vasily Gorbik 
Cc: Christian Borntraeger 
Cc: Yoshinori Sato 
Cc: Rich Felker 
Cc: "David S. Miller" 
Cc: Arnd Bergmann 
Cc: David Hildenbrand 
Cc: Krzysztof Kozlowski 
Cc: Mikulas Patocka 
Cc: Luc Van Oostenryck 
Cc: Mike Rapoport 
Cc: Palmer Dabbelt 
Cc: Luis Chamberlain 
Cc: Greentime Hu 
Cc: Sebastian Andrzej Siewior 
Cc: Randy Dunlap 
Cc: Jiaxun Yang 
Cc: "Peter Zijlstra (Intel)" 
Cc: Christophe Leroy 
Cc: Gerald Schaefer 
Cc: Niklas Schnelle 
Cc: Pierre Morel 
Cc: Ingo Molnar 
Cc: Kuninori Morimoto 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib: add fast path for find_first_*_bit() and find_last_bit()

2021-05-07T02:24:12+00:00

Similarly to bitmap functions, users would benefit if we'll handle a case
of small-size bitmaps that fit into a single word.

While here, move the find_last_bit() declaration to bitops/find.h where
other find_*_bit() functions sit.

Link: https://lkml.kernel.org/r/20210401003153.97325-11-yury.norov@gmail.com
Signed-off-by: Yury Norov 
Acked-by: Rasmus Villemoes 
Acked-by: Andy Shevchenko 
Cc: Alexey Klimov 
Cc: Arnd Bergmann 
Cc: David Sterba 
Cc: Dennis Zhou 
Cc: Geert Uytterhoeven 
Cc: Jianpeng Ma 
Cc: Joe Perches 
Cc: John Paul Adrian Glaubitz 
Cc: Josh Poimboeuf 
Cc: Rich Felker 
Cc: Stefano Brivio 
Cc: Wei Yang 
Cc: Wolfram Sang 
Cc: Yoshinori Sato 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib: add fast path for find_next_*_bit()

2021-05-07T02:24:12+00:00

Similarly to bitmap functions, find_next_*_bit() users will benefit if
we'll handle a case of bitmaps that fit into a single word inline.  In the
very best case, the compiler may replace a function call with a few
instructions.

This is the quite typical find_next_bit() user:

	unsigned int cpumask_next(int n, const struct cpumask *srcp)
	{
		/* -1 is a legal arg here. */
		if (n != -1)
			cpumask_check(n);
		return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n + 1);
	}
	EXPORT_SYMBOL(cpumask_next);

Currently, on ARM64 the generated code looks like this:
	0000000000000000 :
	   0:   a9bf7bfd        stp     x29, x30, [sp, #-16]!
	   4:   11000402        add     w2, w0, #0x1
	   8:   aa0103e0        mov     x0, x1
	   c:   d2800401        mov     x1, #0x40                       // #64
	  10:   910003fd        mov     x29, sp
	  14:   93407c42        sxtw    x2, w2
	  18:   94000000        bl      0 
	  1c:   a8c17bfd        ldp     x29, x30, [sp], #16
	  20:   d65f03c0        ret
	  24:   d503201f        nop

After applying this patch:
	0000000000000140 :
	 140:   11000400        add     w0, w0, #0x1
	 144:   93407c00        sxtw    x0, w0
	 148:   f100fc1f        cmp     x0, #0x3f
	 14c:   54000168        b.hi    178   // b.pmore
	 150:   f9400023        ldr     x3, [x1]
	 154:   92800001        mov     x1, #0xffffffffffffffff         // #-1
	 158:   9ac02020        lsl     x0, x1, x0
	 15c:   52800802        mov     w2, #0x40                       // #64
	 160:   8a030001        and     x1, x0, x3
	 164:   dac00020        rbit    x0, x1
	 168:   f100003f        cmp     x1, #0x0
	 16c:   dac01000        clz     x0, x0
	 170:   1a800040        csel    w0, w2, w0, eq  // eq = none
	 174:   d65f03c0        ret
	 178:   52800800        mov     w0, #0x40                       // #64
	 17c:   d65f03c0        ret

find_next_bit() call is replaced with 6 instructions.  find_next_bit()
itself is 41 instructions plus function call overhead.

Despite inlining, the scripts/bloat-o-meter report smaller .text size
after applying the series:
	add/remove: 11/9 grow/shrink: 233/176 up/down: 5780/-6768 (-988)

Link: https://lkml.kernel.org/r/20210401003153.97325-10-yury.norov@gmail.com
Signed-off-by: Yury Norov 
Acked-by: Rasmus Villemoes 
Acked-by: Andy Shevchenko 
Cc: Alexey Klimov 
Cc: Arnd Bergmann 
Cc: David Sterba 
Cc: Dennis Zhou 
Cc: Geert Uytterhoeven 
Cc: Jianpeng Ma 
Cc: Joe Perches 
Cc: John Paul Adrian Glaubitz 
Cc: Josh Poimboeuf 
Cc: Rich Felker 
Cc: Stefano Brivio 
Cc: Wei Yang 
Cc: Wolfram Sang 
Cc: Yoshinori Sato 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib: inline _find_next_bit() wrappers

2021-05-07T02:24:12+00:00

lib/find_bit.c declares five single-line wrappers for _find_next_bit().
We may turn those wrappers to inline functions.  It eliminates unneeded
function calls and opens room for compile-time optimizations.

Link: https://lkml.kernel.org/r/20210401003153.97325-8-yury.norov@gmail.com
Signed-off-by: Yury Norov 
Acked-by: Rasmus Villemoes 
Acked-by: Andy Shevchenko 
Cc: Alexey Klimov 
Cc: Arnd Bergmann 
Cc: David Sterba 
Cc: Dennis Zhou 
Cc: Geert Uytterhoeven 
Cc: Jianpeng Ma 
Cc: Joe Perches 
Cc: John Paul Adrian Glaubitz 
Cc: Josh Poimboeuf 
Cc: Rich Felker 
Cc: Stefano Brivio 
Cc: Wei Yang 
Cc: Wolfram Sang 
Cc: Yoshinori Sato 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib: extend the scope of small_const_nbits() macro

2021-05-07T02:24:11+00:00

find_bit would also benefit from small_const_nbits() optimizations.  The
detailed comment is provided by Rasmus Villemoes.

Link: https://lkml.kernel.org/r/20210401003153.97325-6-yury.norov@gmail.com
Suggested-by: Rasmus Villemoes 
Signed-off-by: Yury Norov 
Acked-by: Rasmus Villemoes 
Acked-by: Andy Shevchenko 
Cc: Alexey Klimov 
Cc: Arnd Bergmann 
Cc: David Sterba 
Cc: Dennis Zhou 
Cc: Geert Uytterhoeven 
Cc: Jianpeng Ma 
Cc: Joe Perches 
Cc: John Paul Adrian Glaubitz 
Cc: Josh Poimboeuf 
Cc: Rich Felker 
Cc: Stefano Brivio 
Cc: Wei Yang 
Cc: Wolfram Sang 
Cc: Yoshinori Sato 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'mips_5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux

2021-04-29T18:28:08+00:00

Pull MIPS updates from Thomas Bogendoerfer:

 - removed get_fs/set_fs

 - removed broken/unmaintained MIPS KVM trap and emulate support

 - added support for Loongson-2K1000

 - fixes and cleanups

* tag 'mips_5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: (107 commits)
  MIPS: BCM63XX: Use BUG_ON instead of condition followed by BUG.
  MIPS: select ARCH_KEEP_MEMBLOCK unconditionally
  mips: Do not include hi and lo in clobber list for R6
  MIPS:DTS:Correct the license for Loongson-2K
  MIPS:DTS:Fix label name and interrupt number of ohci for Loongson-2K
  MIPS: Avoid handcoded DIVU in `__div64_32' altogether
  lib/math/test_div64: Correct the spelling of "dividend"
  lib/math/test_div64: Fix error message formatting
  mips/bootinfo:correct some comments of fw_arg
  MIPS: Avoid DIVU in `__div64_32' is result would be zero
  MIPS: Reinstate platform `__div64_32' handler
  div64: Correct inline documentation for `do_div'
  lib/math: Add a `do_div' test module
  MIPS: Makefile: Replace -pg with CC_FLAGS_FTRACE
  MIPS: pci-legacy: revert "use generic pci_enable_resources"
  MIPS: Loongson64: Add kexec/kdump support
  MIPS: pci-legacy: use generic pci_enable_resources
  MIPS: pci-legacy: remove busn_resource field
  MIPS: pci-legacy: remove redundant info messages
  MIPS: pci-legacy: stop using of_pci_range_to_resource
  ...

Merge tag 'cfi-v5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2021-04-27T17:16:46+00:00

Pull CFI on arm64 support from Kees Cook:
 "This builds on last cycle's LTO work, and allows the arm64 kernels to
  be built with Clang's Control Flow Integrity feature. This feature has
  happily lived in Android kernels for almost 3 years[1], so I'm excited
  to have it ready for upstream.

  The wide diffstat is mainly due to the treewide fixing of mismatched
  list_sort prototypes. Other things in core kernel are to address
  various CFI corner cases. The largest code portion is the CFI runtime
  implementation itself (which will be shared by all architectures
  implementing support for CFI). The arm64 pieces are Acked by arm64
  maintainers rather than coming through the arm64 tree since carrying
  this tree over there was going to be awkward.

  CFI support for x86 is still under development, but is pretty close.
  There are a handful of corner cases on x86 that need some improvements
  to Clang and objtool, but otherwise works well.

  Summary:

   - Clean up list_sort prototypes (Sami Tolvanen)

   - Introduce CONFIG_CFI_CLANG for arm64 (Sami Tolvanen)"

* tag 'cfi-v5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  arm64: allow CONFIG_CFI_CLANG to be selected
  KVM: arm64: Disable CFI for nVHE
  arm64: ftrace: use function_nocfi for ftrace_call
  arm64: add __nocfi to __apply_alternatives
  arm64: add __nocfi to functions that jump to a physical address
  arm64: use function_nocfi with __pa_symbol
  arm64: implement function_nocfi
  psci: use function_nocfi for cpu_resume
  lkdtm: use function_nocfi
  treewide: Change list_sort to use const pointers
  bpf: disable CFI in dispatcher functions
  kallsyms: strip ThinLTO hashes from static functions
  kthread: use WARN_ON_FUNCTION_MISMATCH
  workqueue: use WARN_ON_FUNCTION_MISMATCH
  module: ensure __cfi_check alignment
  mm: add generic function_nocfi macro
  cfi: add __cficanonical
  add support for Clang CFI