Pull asm-generic updates from Arnd Bergmann:
 "These are cleanups for architecture specific header files:

   - the comments in include/linux/syscalls.h have gone out of sync and
     are really pointless, so these get removed

   - The asm/bitsperlong.h header no longer needs to be architecture
     specific on modern compilers, so use a generic version for newer
     architectures that use new enough userspace compilers

   - A cleanup for virt_to_pfn/virt_to_bus to have proper type checking,
     forcing the use of pointers"

* tag 'asm-generic-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  syscalls: Remove file path comments from headers
  tools arch: Remove uapi bitsperlong.h of hexagon and microblaze
  asm-generic: Unify uapi bitsperlong.h for arm64, riscv and loongarch
  m68k/mm: Make pfn accessors static inlines
  arm64: memory: Make virt_to_pfn() a static inline
  ARM: mm: Make virt_to_pfn() a static inline
  asm-generic/page.h: Make pfn accessors static inlines
  xen/netback: Pass (void *) to virt_to_page()
  netfs: Pass a pointer to virt_to_page()
  cifs: Pass a pointer to virt_to_page() in cifsglob
  cifs: Pass a pointer to virt_to_page()
  riscv: mm: init: Pass a pointer to virt_to_page()
  ARC: init: Pass a pointer to virt_to_pfn() in init
  m68k: Pass a pointer to virt_to_pfn() virt_to_page()
  fs/proc/kcore.c: Pass a pointer to virt_addr_valid()

The Arm documentation has moved to Documentation/arch/arm; update
references within arch/arm to match.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Alim Akhtar <alim.akhtar@samsung.com>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: linux-doc@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Making virt_to_pfn() a static inline taking a strongly typed
(const void *) makes the contract of a passing a pointer of that
type to the function explicit and exposes any misuse of the
macro virt_to_pfn() acting polymorphic and accepting many types
such as (void *), (unitptr_t) or (unsigned long) as arguments
without warnings.

Doing this is a bit intrusive: virt_to_pfn() requires
PHYS_PFN_OFFSET and PAGE_SHIFT to be defined, and this is defined in
<asm/page.h>, so this must be included *before* <asm/memory.h>.

The use of macros were obscuring the unclear inclusion order here,
as the macros would eventually be resolved, but a static inline
like this cannot be compiled with unresolved macros.

The naive solution to include <asm/page.h> at the top of
<asm/memory.h> does not work, because <asm/memory.h> sometimes
includes <asm/page.h> at the end of itself, which would create a
confusing inclusion loop. So instead, take the approach to always
unconditionally include <asm/page.h> at the end of <asm/memory.h>

arch/arm uses <asm/memory.h> explicitly in a lot of places,
however it turns out that if we just unconditionally include
<asm/memory.h> into <asm/page.h> and switch all inclusions of
<asm/memory.h> to <asm/page.h> instead, we enforce the right
order and <asm/memory.h> will always have access to the
definitions.

Put an inclusion guard in place making it impossible to include
<asm/memory.h> explicitly.

Link: https://lore.kernel.org/linux-mm/20220701160004.2ffff4e5ab59a55499f4c736@linux-foundation.org/
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Now that we can dispatch all VFP and iWMMXT related undef exceptions
using undef hooks implemented in C code, we no longer need the asm entry
code that takes care of this unless we are using FPE, so we can move it
into the FPE entry code. As this means it is ARM only, we can remove the
Thumb2 specific decorations as well.

It also means the non-standard, asm-only calling convention where
returning via LR means failure and returning via R9 means success is now
only used on legacy platforms that lack any kind of function return
prediction, avoiding the associated performance impact.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Define a undef hook to deal with undef exceptions triggered by iwmmxt
instructions that were issued with the coprocessor disabled. This
removes the dependency on the coprocessor dispatch code in entry-armv.S,
which will be made NWFPE-only in a subsequent patch.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Now that the only remaining coprocessor instructions being handled via
the dispatch in entry-armv.S are ones that only exist in a ARM (A32)
encoding, we can simplify the handling of Thumb undef exceptions, and
send them straight to the undefined instruction handlers in C code.

This also means we can drop the code that partially decodes the
instruction to decide whether it is a 16-bit or 32-bit Thumb
instruction: this is all taken care of by the undef hook.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Now that the VFP support code has been reimplemented as a C function
that takes a struct pt_regs pointer and an opcode, we can use the
existing undef_hook framework to deal with undef exceptions triggered by
VFP instructions instead of having special handling in assembler.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

We keep track of which coprocessor triggered a fault in the used_cp[]
array in thread_info, but this data is never used anywhere. So let's
remove it.

Linus did some digging and found out that the last user of this field
was removed in commit bb1a773d5b6b ("kill unused dump_fpu() instances").

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

The assembler does not permit 'LDR PC, <sym>' when the symbol lives in a
different section, which is why we have been relying on rather fragile
open-coded arithmetic to load the address of the vector_swi routine into
the program counter using a single LDR instruction in the SWI slot in
the vector table. The literal was moved to a different section to in
commit 19accfd373847 ("ARM: move vector stubs") to ensure that the
vector stubs page does not need to be mapped readable for user space,
which is the case for the vector page itself, as it carries the kuser
helpers as well.

So the cross-section literal load is open-coded, and this relies on the
address of vector_swi to be at the very start of the vector stubs page,
and we won't notice if we got it wrong until booting the kernel and see
it break. Fortunately, it was guaranteed to break, so this was fragile
but not problematic.

Now that we have added two other variants of the vector table, we have 3
occurrences of the same trick, and so the size of our ISA/compiler/CPU
validation space has tripled, in a way that may cause regressions to only
be observed once booting the image in question on a CPU that exercises a
particular vector table.

So let's switch to true cross section references, and let the linker fix
them up like it fixes up all the other cross section references in the
vector page.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>