This overrides arch_get_mappabble_range() on s390 platform which will be
used with recently added generic framework.  It modifies the existing
range check in vmem_add_mapping() using arch_get_mappable_range().  It
also adds a VM_BUG_ON() check that would ensure that mhp_range_allowed()
has already been called on the hotplug path.

Link: https://lkml.kernel.org/r/1612149902-7867-4-git-send-email-anshuman.khandual@arm.comSigned-off-by: NAnshuman Khandual <anshuman.khandual@arm.com>
Acked-by: NHeiko Carstens <hca@linux.ibm.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: teawater <teawaterz@linux.alibaba.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This overrides arch_get_mappable_range() on arm64 platform which will be
used with recently added generic framework.  It drops
inside_linear_region() and subsequent check in arch_add_memory() which are
no longer required.  It also adds a VM_BUG_ON() check that would ensure
that mhp_range_allowed() has already been called.

Link: https://lkml.kernel.org/r/1612149902-7867-3-git-send-email-anshuman.khandual@arm.comSigned-off-by: NAnshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: teawater <teawaterz@linux.alibaba.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Andestech(nds32) never had <asm/procinfo.h>.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NGreentime Hu <green.hu@gmail.com>
Signed-off-by: NGreentime Hu <green.hu@gmail.com>

Use the proper get_kernel_nofault helper to access an unsafe kernel
pointer without faulting instead of playing with set_fs and get_user.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NNick Hu <nickhu@andestech.com>
Acked-by: NGreentime Hu <green.hu@gmail.com>
Signed-off-by: NGreentime Hu <green.hu@gmail.com>

dump_inst has a return before actually doing anything, so just drop the
whole thing.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NNick Hu <nickhu@andestech.com>
Acked-by: NGreentime Hu <green.hu@gmail.com>
Signed-off-by: NGreentime Hu <green.hu@gmail.com>

CONFIG_CROSS_COMPILE is gone since commit f1089c92 ("kbuild: remove
CONFIG_CROSS_COMPILE support").
Signed-off-by: NKrzysztof Kozlowski <krzk@kernel.org>
Acked-by: NGreentime Hu <green.hu@gmail.com>
Signed-off-by: NGreentime Hu <green.hu@gmail.com>

The Andes platform code is not a clock provider, and just needs to call
of_clk_init().

Hence it can include <linux/of_clk.h> instead of <linux/clk-provider.h>.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NGreentime Hu <green.hu@gmail.com>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NGreentime Hu <green.hu@gmail.com>

Function set_pmd_at is to set pmd entry, if tlb entry need to be flushed,
there exists pmdp_huge_clear_flush alike function before set_pmd_at is
called.  So it is not necessary to call flush_tlb_all in this function.

In these scenarios, tlb for the pmd range needs to be flushed:

 - privilege degrade such as wrprotect is set on the pmd entry

 - pmd entry is cleared

 - there is exception if set_pmd_at is issued by dup_mmap, since
   flush_tlb_mm is called for parent process, it is not necessary to
   flush tlb in function copy_huge_pmd.

Link: http://lkml.kernel.org/r/1592990792-1923-3-git-send-email-maobibo@loongson.cnSigned-off-by: NBibo Mao <maobibo@loongson.cn>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Daniel Silsby <dansilsby@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

As David suggested, simply passing 'struct zone *zone' is enough.  We can
get all needed information from 'struct zone*' easily.

Link: https://lkml.kernel.org/r/20210122135956.5946-4-bhe@redhat.comSigned-off-by: NBaoquan He <bhe@redhat.com>
Suggested-by: NDavid Hildenbrand <david@redhat.com>
Reviewed-by: NMike Rapoport <rppt@linux.ibm.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The current memmap_init_zone() only handles memory region inside one zone,
actually memmap_init() does the memmap init of one zone.  So rename both
of them accordingly.

Link: https://lkml.kernel.org/r/20210122135956.5946-3-bhe@redhat.comSigned-off-by: NBaoquan He <bhe@redhat.com>
Reviewed-by: NMike Rapoport <rppt@linux.ibm.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "mm: clean up names and parameters of memmap_init_xxxx functions", v5.

This patchset corrects inappropriate function names of memmap_init_xxx,
and simplify parameters of functions in the code flow.  And also fix a
prototype warning reported by lkp.

This patch (of 5);

Kernel test robot calling make with 'W=1' is triggering warning like
below for memmap_init_zone() function.

  mm/page_alloc.c:6259:23: warning: no previous prototype for 'memmap_init_zone' [-Wmissing-prototypes]
   6259 | void __meminit __weak memmap_init_zone(unsigned long size, int nid,
        |                       ^~~~~~~~~~~~~~~~

Fix it by adding the function declaration in include/linux/mm.h.  Since
memmap_init_zone() has a generic version with '__weak', the declaratoin in
ia64 header file can be simply removed.

Link: https://lkml.kernel.org/r/20210122135956.5946-1-bhe@redhat.com
Link: https://lkml.kernel.org/r/20210122135956.5946-2-bhe@redhat.comSigned-off-by: NBaoquan He <bhe@redhat.com>
Reported-by: Nkernel test robot <lkp@intel.com>
Reviewed-by: NMike Rapoport <rppt@linux.ibm.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On a high level, this patch allows running KUnit KASAN tests with the
hardware tag-based KASAN mode.

Internally, this change reenables tag checking at the end of each KASAN
test that triggers a tag fault and leads to tag checking being disabled.

Also simplify is_write calculation in report_tag_fault.

With this patch KASAN tests are still failing for the hardware tag-based
mode; fixes come in the next few patches.

[andreyknvl@google.com: export HW_TAGS symbols for KUnit tests]
  Link: https://lkml.kernel.org/r/e7eeb252da408b08f0c81b950a55fb852f92000b.1613155970.git.andreyknvl@google.com

Link: https://linux-review.googlesource.com/id/Id94dc9eccd33b23cda4950be408c27f879e474c8
Link: https://lkml.kernel.org/r/51b23112cf3fd62b8f8e9df81026fa2b15870501.1610733117.git.andreyknvl@google.comSigned-off-by: NAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: NVincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since CONFIG_EXPERIMENTAL was removed in 2013, go ahead and drop it
from any defconfig files.

Link: https://lkml.kernel.org/r/20210115010011.29483-1-rdunlap@infradead.org
Fixes: 3d374d09 ("final removal of CONFIG_EXPERIMENTAL")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Brian Cain <bcain@codeaurora.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pass code model and stack alignment to the linker as these are not
stored in LLVM bitcode, and allow CONFIG_LTO_CLANG* to be enabled.
Signed-off-by: NSami Tolvanen <samitolvanen@google.com>
Reviewed-by: NKees Cook <keescook@chromium.org>

Clang incorrectly inlines functions with differing stack protector
attributes, which breaks __restore_processor_state() that relies on
stack protector being disabled. This change disables LTO for cpu.c
to work aroung the bug.

Link: https://bugs.llvm.org/show_bug.cgi?id=47479Suggested-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NSami Tolvanen <samitolvanen@google.com>

Disable LTO for the vDSO. Note that while we could use Clang's LTO
for the 64-bit vDSO, it won't add noticeable benefit for the small
amount of C code.
Signed-off-by: NSami Tolvanen <samitolvanen@google.com>
Reviewed-by: NKees Cook <keescook@chromium.org>

Select HAVE_OBJTOOL_MCOUNT if STACK_VALIDATION is selected to use
objtool to generate __mcount_loc sections for dynamic ftrace with
Clang and gcc <5 (later versions of gcc use -mrecord-mcount).
Signed-off-by: NSami Tolvanen <samitolvanen@google.com>
Reviewed-by: NKees Cook <keescook@chromium.org>

The common cros-ec keymap has been defined as macros. This patch uses
the macros to simply linux,keymap in cros-ec-keyboard.dtsi file.

This patch also creates an alias for keyboard-controller to make it
easier to override the keymap in board-specific dts later.
Signed-off-by: NPhilip Chen <philipchen@chromium.org>
Reviewed-by: NStephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20210115143555.v6.2.I9ec9c3c61eded22a5f7fbff838d23fc95ec7cfe0@changeidSigned-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

When CONFIG_EPOLL is not set/enabled, sys_oabi-compat.c has build
errors. Fix these by surrounding them with ifdef CONFIG_EPOLL/endif
and providing stubs for the "EPOLL is not set" case.

../arch/arm/kernel/sys_oabi-compat.c: In function 'sys_oabi_epoll_ctl':
../arch/arm/kernel/sys_oabi-compat.c:257:6: error: implicit declaration of function 'ep_op_has_event' [-Werror=implicit-function-declaration]
  257 |  if (ep_op_has_event(op) &&
      |      ^~~~~~~~~~~~~~~
../arch/arm/kernel/sys_oabi-compat.c:264:9: error: implicit declaration of function 'do_epoll_ctl'; did you mean 'sys_epoll_ctl'? [-Werror=implicit-function-declaration]
  264 |  return do_epoll_ctl(epfd, op, fd, &kernel, false);
      |         ^~~~~~~~~~~~

Fixes: c281634c ("ARM: compat: remove KERNEL_DS usage in sys_oabi_epoll_ctl()")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com> # from an lkp .config file
Cc: linux-arm-kernel@lists.infradead.org
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: patches@armlinux.org.uk
Acked-by: NNicolas Pitre <nico@fluxnic.net>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

The 'syscall' variables are not directly used in the commands.
Remove the $(srctree)/ prefix because we can rely on VPATH.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

The rules in these Makefiles cannot detect the command line change
because the prerequisite 'FORCE' is missing.

Adding 'FORCE' will result in the headers being rebuilt every time
because the 'targets' additions are also wrong; the file paths in
'targets' must be relative to the current Makefile.

Fix all of them so the if_changed rules work correctly.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>

If there is a initramfs linked into the kernel which will be
freed later on there is free memory somewhere between _etext
and _end, thus using _end for min_low_pfn is not correct.
This may lead to issues in dma_capable when checking
'min(addr, end) < phys_to_dma(dev, PFN_PHYS(min_low_pfn)))'
as the address addr might be below min_low_pfn. Picked
find_limits from architecture arm for applying min_low_pfn and
max_low_pfn. Maybe using _etext for min_low_pfn would be
fine too.
Signed-off-by: NAndreas Oetken <andreas.oetken@siemens.com>
Signed-off-by: NLey Foon Tan <ley.foon.tan@intel.com>

The tls pointer must be pushed on the stack prior to calling nios2_clone
as it is the 5th function argument. Prior handling of the tls pointer was
done inside former called function copy_thread_tls using the r8 register
from the current_pt_regs directly. This was a bad design and resulted in
the current bug introduced in 04bd52fb.

Fixes: 04bd52fb ("nios2: enable HAVE_COPY_THREAD_TLS, switch to kernel_clone_args")
Signed-off-by: NAndreas Oetken <andreas.oetken@siemens.com>
Signed-off-by: NLey Foon Tan <ley.foon.tan@intel.com>
Acked-by: NChristian Brauner <christian.brauner@ubuntu.com>

We need to take the mmap lock around find_vma() and subsequent use of the
VMA. Otherwise, we can race with concurrent operations like munmap(), which
can lead to use-after-free accesses to freed VMAs.

Fixes: 1000197d ("nios2: System calls handling")
Signed-off-by: NJann Horn <jannh@google.com>
Signed-off-by: NLey Foon Tan <ley.foon.tan@intel.com>

Fix several of the same warning by using a GCC statement expression
(extension):

../arch/sparc/include/asm/cmpxchg_32.h:28:22: warning: value computed is not used [-Wunused-value]
   28 | #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))

Passes sparc32 allmodconfig with no xchg warnings.
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When userspace calls mprotect() to enable ADI on an address range,
do_mprotect_pkey() calls arch_validate_prot() to validate new
protection flags. arch_validate_prot() for sparc looks at the first
VMA associated with address range to verify if ADI can indeed be
enabled on this address range. This has two issues - (1) Address
range might cover multiple VMAs while arch_validate_prot() looks at
only the first VMA, (2) arch_validate_prot() peeks at VMA without
holding mmap lock which can result in race condition.

arch_validate_flags() from commit c462ac28 ("mm: Introduce
arch_validate_flags()") allows for VMA flags to be validated for all
VMAs that cover the address range given by user while holding mmap
lock. This patch updates sparc code to move the VMA check from
arch_validate_prot() to arch_validate_flags() to fix above two
issues.
Suggested-by: NJann Horn <jannh@google.com>
Suggested-by: NChristoph Hellwig <hch@infradead.org>
Suggested-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NKhalid Aziz <khalid.aziz@oracle.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes coccicheck warning:

/arch/sparc/mm/srmmu.c:354:42-43: WARNING comparing pointer to 0

Avoid pointer type value compared to 0.
Reported-by: NTosk Robot <tencent_os_robot@tencent.com>
Signed-off-by: NKaixu Xia <kaixuxia@tencent.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix Sparc build when CONFIG_PROC_FS is not enabled.

Fixes this build error:
arch/sparc/kernel/led.c:107:30: error: 'led_proc_ops' defined but not used [-Werror=unused-const-variable=]
     107 | static const struct proc_ops led_proc_ops = {
         |                              ^~~~~~~~~~~~
   cc1: all warnings being treated as errors

Fixes: 97a32539 ("proc: convert everything to "struct proc_ops"")
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Lars Kotthoff <metalhead@metalhead.ws>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The page has just been allocated, so its refcount is 1.  free_unref_page()
is for use on pages which have a zero refcount.  Use __free_page()
like the other implementations of pte_alloc_one().

Fixes: 1ae9ae5f ("sparc: handle pgtable_page_ctor() fail")
Signed-off-by: NMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Reviewed-by: NMike Rapoport <rppt@linux.ibm.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently COMPAT on SPARC64 selects COMPAT_BINFMT_ELF unconditionally,
even when BINFMT_ELF is not enabled. This causes a kconfig warning.

Instead, just select COMPAT_BINFMT_ELF if BINFMT_ELF is enabled.
This builds cleanly with no kconfig warnings.

WARNING: unmet direct dependencies detected for COMPAT_BINFMT_ELF
  Depends on [n]: COMPAT [=y] && BINFMT_ELF [=n]
  Selected by [y]:
  - COMPAT [=y] && SPARC64 [=y]

Fixes: 26b4c912 ("sparc,sparc64: unify Kconfig files")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The sparc64 qemu machines uses sunhme network hardware by default, so for
simple NFS boot testing using qemu, having CONFIG_HAPPYMEAL is useful.
And so we need also IP_PNP_DHCP for NFS boot.
For the same reason we need to enable its storage which is a PATA_CMD64.
And finally, we need CONFIG_DEVTMPFS for handling recent udev/systemd.

All those options will permit to enable boot testing in both kernelCI
and gentoo's kernelCI.
Signed-off-by: NCorentin Labbe <clabbe@baylibre.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace the ide options with the equivalent libata options.  This has
been carried by various downstreams like the linux-build-test repo
for years already.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This fixes a bug where a clone syscall that is restarted due to a
pending signal is restarted with garbage in the register %o0 that holds
the clone flags.

This keep the original %i0 of a syscall (as seen from the trap handler)
in %l6 rather than %l5. This is done because for clone (and also qfork)
%l5 is used as a temporary variable in the same register window. Before
this, that temporary value would be the value that was then incorrectly
used as the orig_i0 argument to do_notify_resume.

In order to preserve %l6, the temporary usage of %l6 in ret_sys_call is
changed to use %l5 instead and the setting %l6 to 0 or 1 was removed.
The use of that 0 or 1 value in %l6 was removed in commit
28e61036.
Signed-off-by: NAndreas Larsson <andreas@gaisler.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit cca079ef changed sparc32 to use
memblocks instead of bootmem, but also made high memory available via
memblock allocation which does not work together with e.g. phys_to_virt
and can lead to kernel panic.

This changes back to only low memory being allocatable in the early
stages, now using memblock allocation.
Signed-off-by: NAndreas Larsson <andreas@gaisler.com>
Acked-by: NMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use test_tsk_thread_flag() directly instead of test_ti_thread_flag() to
improve readability when the argument type is struct task_struct, it is
similar with commit 5afc7855 ("arm64: Use test_tsk_thread_flag() for
checking TIF_SINGLESTEP").
Signed-off-by: NTiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 7c86ff99.

There are too many special cases for MIPS not covered by this patch.
In the end it might be better to implement single stepping in userland
than emulating it in the kernel.
Signed-off-by: NThomas Bogendoerfer <tsbogend@alpha.franken.de>

Allow building x86 with PREEMPT_DYNAMIC=n, this is needed for
PREEMPT_RT as it makes no sense to not have full preemption on
PREEMPT_RT.

Fixes: 8c98e8cf723c ("preempt/dynamic: Provide preempt_schedule[_notrace]() static calls")
Reported-by: NMike Galbraith <efault@gmx.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Tested-by: NMike Galbraith <efault@gmx.de>
Link: https://lkml.kernel.org/r/YCK1+JyFNxQnWeXK@hirez.programming.kicks-ass.net

Following the idle loop model, cleanly check for pending rcuog wakeup
before the last rescheduling point upon resuming to guest mode. This
way we can avoid to do it from rcu_user_enter() with the last resort
self-IPI hack that enforces rescheduling.
Suggested-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NFrederic Weisbecker <frederic@kernel.org>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210131230548.32970-6-frederic@kernel.org

Use the new EXPORT_STATIC_CALL_TRAMP() / static_call_mod() to unexport
the static_call_key for the PREEMPT_DYNAMIC calls such that modules
can no longer update these calls.

Having modules change/hi-jack the preemption calls would be horrible.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

When exporting static_call_key; with EXPORT_STATIC_CALL*(), the module
can use static_call_update() to change the function called.  This is
not desirable in general.

Not exporting static_call_key however also disallows usage of
static_call(), since objtool needs the key to construct the
static_call_site.

Solve this by allowing objtool to create the static_call_site using
the trampoline address when it builds a module and cannot find the
static_call_key symbol. The module loader will then try and map the
trampole back to a key before it constructs the normal sites list.

Doing this requires a trampoline -> key associsation, so add another
magic section that keeps those.
Originally-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20210127231837.ifddpn7rhwdaepiu@treble