...modules are using this symbol.
Export it like all other archs to.

Signed-off-by: Richard Weinberger <richard@nod.at>

Commit db2f24dc240856fb1d78005307f1523b7b3c121b
was plain wrong. I did not realize the we are
allowed to loop here.
In fact we have to loop and must not return to userspace
before all SIGSEGVs have been delivered.
Other archs do this directly in their entry code, UML
does it here.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

Commit 16da306849d0 ("um: kill pfn_t") introduced a compile warning for
defconfig (SUBARCH=i386):

  arch/um/kernel/skas/mmu.c:38:206:
      warning: right shift count >= width of type [-Wshift-count-overflow]

Aforementioned patch changes the definition of the phys_to_pfn() macro
from

  ((pfn_t) ((p) >> PAGE_SHIFT))

to

  ((p) >> PAGE_SHIFT)

This effectively changes the phys_to_pfn() expansion's type from
unsigned long long to unsigned long.

Through the callchain init_stub_pte() => mk_pte(), the expansion of
phys_to_pfn() is (indirectly) fed into the 'phys' argument of the
pte_set_val(pte, phys, prot) macro, eventually leading to

  (pte).pte_high = (phys) >> 32;

This results in the warning from above.

Since UML only deals with 32 bit addresses, the upper 32 bits from
'phys' used to be always zero anyway.  Also, all page protection flags
defined by UML don't use any bits beyond bit 9.  Since the contents of a
PTE are defined within architecture scope only, the ->pte_high member
can be safely removed.

Remove the ->pte_high member from struct pte_t.
Rename ->pte_low to ->pte.
Adapt the pte helper macros in arch/um/include/asm/page.h.

Noteworthy is the pte_copy() macro where a smp_wmb() gets dropped.  This
write barrier doesn't seem to be paired with any read barrier though and
thus, was useless anyway.

Fixes: 16da306849d0 ("um: kill pfn_t")
Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The core has developed a need for a "pfn_t" type [1].  Convert the usage
of pfn_t by usermode-linux to an unsigned long, and update pfn_to_phys()
to drop its expectation of a typed pfn.

[1]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002199.html

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull misc vfs updates from Al Viro:
 "All kinds of stuff.  That probably should've been 5 or 6 separate
  branches, but by the time I'd realized how large and mixed that bag
  had become it had been too close to -final to play with rebasing.

  Some fs/namei.c cleanups there, memdup_user_nul() introduction and
  switching open-coded instances, burying long-dead code, whack-a-mole
  of various kinds, several new helpers for ->llseek(), assorted
  cleanups and fixes from various people, etc.

  One piece probably deserves special mention - Neil's
  lookup_one_len_unlocked().  Similar to lookup_one_len(), but gets
  called without ->i_mutex and tries to avoid ever taking it.  That, of
  course, means that it's not useful for any directory modifications,
  but things like getting inode attributes in nfds readdirplus are fine
  with that.  I really should've asked for moratorium on lookup-related
  changes this cycle, but since I hadn't done that early enough...  I
  *am* asking for that for the coming cycle, though - I'm going to try
  and get conversion of i_mutex to rwsem with ->lookup() done under lock
  taken shared.

  There will be a patch closer to the end of the window, along the lines
  of the one Linus had posted last May - mechanical conversion of
  ->i_mutex accesses to inode_lock()/inode_unlock()/inode_trylock()/
  inode_is_locked()/inode_lock_nested().  To quote Linus back then:

    -----
    |    This is an automated patch using
    |
    |        sed 's/mutex_lock(&\(.*\)->i_mutex)/inode_lock(\1)/'
    |        sed 's/mutex_unlock(&\(.*\)->i_mutex)/inode_unlock(\1)/'
    |        sed 's/mutex_lock_nested(&\(.*\)->i_mutex,[     ]*I_MUTEX_\([A-Z0-9_]*\))/inode_lock_nested(\1, I_MUTEX_\2)/'
    |        sed 's/mutex_is_locked(&\(.*\)->i_mutex)/inode_is_locked(\1)/'
    |        sed 's/mutex_trylock(&\(.*\)->i_mutex)/inode_trylock(\1)/'
    |
    |    with a very few manual fixups
    -----

  I'm going to send that once the ->i_mutex-affecting stuff in -next
  gets mostly merged (or when Linus says he's about to stop taking
  merges)"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
  nfsd: don't hold i_mutex over userspace upcalls
  fs:affs:Replace time_t with time64_t
  fs/9p: use fscache mutex rather than spinlock
  proc: add a reschedule point in proc_readfd_common()
  logfs: constify logfs_block_ops structures
  fcntl: allow to set O_DIRECT flag on pipe
  fs: __generic_file_splice_read retry lookup on AOP_TRUNCATED_PAGE
  fs: xattr: Use kvfree()
  [s390] page_to_phys() always returns a multiple of PAGE_SIZE
  nbd: use ->compat_ioctl()
  fs: use block_device name vsprintf helper
  lib/vsprintf: add %*pg format specifier
  fs: use gendisk->disk_name where possible
  poll: plug an unused argument to do_poll
  amdkfd: don't open-code memdup_user()
  cdrom: don't open-code memdup_user()
  rsxx: don't open-code memdup_user()
  mtip32xx: don't open-code memdup_user()
  [um] mconsole: don't open-code memdup_user_nul()
  [um] hostaudio: don't open-code memdup_user()
  ...

Open the memory mapped file with the O_TMPFILE flag when available.

Signed-off-by: Mickaël Salaün <mic@digikod.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Acked-by: Tristan Schmelcher <tschmelcher@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Remove the insecure 0777 mode for temporary file to prohibit other users
to change the executable mapped code.

An attacker could gain access to the mapped file descriptor from the
temporary file (before it is unlinked) in a read-only mode but it should
not be accessible in write mode to avoid arbitrary code execution.

To not change the hostfs behavior, the temporary file creation
permission now depends on the current umask(2) and the implementation of
mkstemp(3).

Signed-off-by: Mickaël Salaün <mic@digikod.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Acked-by: Tristan Schmelcher <tschmelcher@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

This brings SECCOMP_MODE_STRICT and SECCOMP_MODE_FILTER support through
prctl(2) and seccomp(2) to User-mode Linux for i386 and x86_64
subarchitectures.

secure_computing() is called first in handle_syscall() so that the
syscall emulation will be aborted quickly if matching a seccomp rule.

This is inspired from Meredydd Luff's patch
(https://gerrit.chromium.org/gerrit/21425).

Signed-off-by: Mickaël Salaün <mic@digikod.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Meredydd Luff <meredydd@senatehouse.org>
Cc: David Drysdale <drysdale@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Kees Cook <keescook@chromium.org>

Add subarchitecture-independent implementation of asm-generic/syscall.h
allowing access to user system call parameters and results:
* syscall_get_nr()
* syscall_rollback()
* syscall_get_error()
* syscall_get_return_value()
* syscall_set_return_value()
* syscall_get_arguments()
* syscall_set_arguments()
* syscall_get_arch() provided by arch/x86/um/asm/syscall.h

This provides the necessary syscall helpers needed by
HAVE_ARCH_SECCOMP_FILTER plus syscall_get_error().

This is inspired from Meredydd Luff's patch
(https://gerrit.chromium.org/gerrit/21425).

Signed-off-by: Mickaël Salaün <mic@digikod.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Cc: Meredydd Luff <meredydd@senatehouse.org>
Cc: David Drysdale <drysdale@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Kees Cook <keescook@chromium.org>

This fix two related bugs:
* PTRACE_GETREGS doesn't get the right orig_ax (syscall) value
* PTRACE_SETREGS can't set the orig_ax value (erased by initial value)

Get rid of the now useless and error-prone get_syscall().

Fix inconsistent behavior in the ptrace implementation for i386 when
updating orig_eax automatically update the syscall number as well. This
is now updated in handle_syscall().

Signed-off-by: Mickaël Salaün <mic@digikod.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Cc: Thomas Meyer <thomas@m3y3r.de>
Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: Anton Ivanov <aivanov@brocade.com>
Cc: Meredydd Luff <meredydd@senatehouse.org>
Cc: David Drysdale <drysdale@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Kees Cook <keescook@chromium.org>