Pull UML updates from Richard Weinberger:

 - Lots of cleanups, mostly from Benjamin Berg and Tiwei Bie

 - Removal of unused code

 - Fix for sparse warnings

 - Cleanup around stub_exe()

* tag 'uml-for-linus-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: (68 commits)
  hostfs: Fix the NULL vs IS_ERR() bug for __filemap_get_folio()
  um: move thread info into task
  um: Always dump trace for specified task in show_stack
  um: vector: Do not use drvdata in release
  um: net: Do not use drvdata in release
  um: ubd: Do not use drvdata in release
  um: ubd: Initialize ubd's disk pointer in ubd_add
  um: virtio_uml: query the number of vqs if supported
  um: virtio_uml: fix call_fd IRQ allocation
  um: virtio_uml: send SET_MEM_TABLE message with the exact size
  um: remove broken double fault detection
  um: remove duplicate UM_NSEC_PER_SEC definition
  um: remove file sync for stub data
  um: always include kconfig.h and compiler-version.h
  um: set DONTDUMP and DONTFORK flags on KASAN shadow memory
  um: fix sparse warnings in signal code
  um: fix sparse warnings from regset refactor
  um: Remove double zero check
  um: fix stub exe build with CONFIG_GCOV
  um: Use os_set_pdeathsig helper in winch thread/process
  ...

Pull asm-generic updates from Arnd Bergmann:
 "These are a number of unrelated cleanups, generally simplifying the
  architecture specific header files:

   - A series from Al Viro simplifies asm/vga.h, after it turns out that
     most of it can be generalized.

   - A series from Julian Vetter adds a common version of
     memcpy_{to,from}io() and memset_io() and changes most architectures
     to use that instead of their own implementation

   - A series from Niklas Schnelle concludes his work to make PC style
     inb()/outb() optional

   - Nicolas Pitre contributes improvements for the generic do_div()
     helper

   - Christoph Hellwig adds a generic version of page_to_phys() and
     phys_to_page(), replacing the slightly different architecture
     specific definitions.

   - Uwe Kleine-Koenig has a minor cleanup for ioctl definitions"

* tag 'asm-generic-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: (24 commits)
  empty include/asm-generic/vga.h
  sparc: get rid of asm/vga.h
  asm/vga.h: don't bother with scr_mem{cpy,move}v() unless we need to
  vt_buffer.h: get rid of dead code in default scr_...() instances
  tty: serial: export serial_8250_warn_need_ioport
  lib/iomem_copy: fix kerneldoc format style
  hexagon: simplify asm/io.h for !HAS_IOPORT
  loongarch: Use new fallback IO memcpy/memset
  csky: Use new fallback IO memcpy/memset
  arm64: Use new fallback IO memcpy/memset
  New implementation for IO memcpy and IO memset
  watchdog: Add HAS_IOPORT dependency for SBC8360 and SBC7240
  __arch_xprod64(): make __always_inline when optimizing for performance
  ARM: div64: improve __arch_xprod_64()
  asm-generic/div64: optimize/simplify __div64_const32()
  lib/math/test_div64: add some edge cases relevant to __div64_const32()
  asm-generic: add an optional pfn_valid check to page_to_phys
  asm-generic: provide generic page_to_phys and phys_to_page implementations
  asm-generic/io.h: Remove I/O port accessors for HAS_IOPORT=n
  tty: serial: handle HAS_IOPORT dependencies
  ...

This selects the THREAD_INFO_IN_TASK option for UM and changes the way
that the current task is discovered. This is trivial though, as UML
already tracks the current task in cpu_tasks[] and this can be used to
retrieve it.

Also remove the signal handler code that copies the thread information
into the IRQ stack. It is obsolete now, which also means that the
mentioned race condition cannot happen anymore.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Reviewed-by: Hajime Tazaki <thehajime@gmail.com>
Link: https://patch.msgid.link/20241111102910.46512-1-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

The show_stack function had some code to detect double faults. However,
the logic is wrong and it would e.g. trigger if a WARNING happened
inside an IRQ.

Remove it without trying to add a new logic. The current behaviour,
which will just fault repeatedly until the IRQ stack is used up and the
host kills UML, seems to be good enough.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103150506.1367695-5-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Just remove the first entry as there is a second later on.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103150506.1367695-4-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

There is no need to sync the stub code to "disk" for the other process
to see the correct memory. Drop the fsync there and remove the helper
function.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103150506.1367695-3-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Since commit a95b37e20db9 ("kbuild: get <linux/compiler_types.h> out of
<linux/kconfig.h>") we can safely include these files in userspace code.
Doing so simplifies matters as options do not need to be exported via
asm-offsets.h anymore.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103150506.1367695-2-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

page_to_phys is duplicated by all architectures, and from some strange
reason placed in <asm/io.h> where it doesn't fit at all.

phys_to_page is only provided by a few architectures despite having a lot
of open coded users.

Provide generic versions in <asm-generic/memory_model.h> to make these
helpers more easily usable.

Note with this patch powerpc loses the CONFIG_DEBUG_VIRTUAL pfn_valid
check.  It will be added back in a generic version later.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

This helper can be used to set the parent-death signal of the calling
process to SIGKILL to ensure that the process will be killed if the
UML kernel dies unexpectedly without proper cleanup. This helper will
be used in the follow-up patches.

Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241024142828.2612828-2-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

The PTRACE_GETREGSET API has now existed since Linux 2.6.33. The XSAVE
CPU feature should also be sufficiently common to be able to rely on it.

With this, define our internal FP state to be the hosts XSAVE data. Add
discovery for the hosts XSAVE size and place the FP registers at the end
of task_struct so that we can adjust the size at runtime.

Next we can implement the regset API on top and update the signal
handling as well as ptrace APIs to use them. Also switch coredump
creation to use the regset API and finally set HAVE_ARCH_TRACEHOOK.

This considerably improves the signal frames. Previously they might not
have contained all the registers (i386) and also did not have the
sizes and magic values set to the correct values to permit userspace to
decode the frame.

As a side effect, this will permit UML to run on hosts with newer CPU
extensions (such as AMX) that need even more register state.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241023094120.4083426-1-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>