Add forward declaration of struct seq_file before using it in a
function prototype.

Fixes: 04a8682a71be ("fs/proc: Introduce /proc/pid/timens_offsets")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andrei Vagin <avagin@gmail.com>
Link: https://lore.kernel.org/all/aDlskzKIAULMlwPj@gondor.apana.org.au

All users of the time releated parts of the vDSO are now using the generic
storage implementation. Remove the therefore unnecessary compatibility
accessor functions and symbols.

Co-developed-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-18-13a4669dfc8c@linutronix.de

Historically each architecture defined their own way to store the vDSO
data page. Add a generic mechanism to provide storage for that page.

Furthermore this generic storage will be extended to also provide
uniform storage for *non*-time-related data, like the random state or
architecture-specific data. These will have their own pages and data
structures, so rename 'vdso_data' into 'vdso_time_data' to make that
split clear from the name.

Also introduce a new consistent naming scheme for the symbols related to
the vDSO, which makes it clear if the symbol is accessible from
userspace or kernel space and the type of data behind the symbol.

The generic fault handler contains an optimization to prefault the vvar
page when the timens page is accessed. This was lifted from s390 and x86.

Co-developed-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-5-13a4669dfc8c@linutronix.de

Slimming down recursive header includes.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Thomas Gleixner <tglx@linutronix.de>

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

The arch_get_vdso_data() function is defined separately on each architecture,
but only called when CONFIG_TIME_NS is set. If the definition is a global
function, this causes a W=1 warning without TIME_NS:

arch/x86/entry/vdso/vma.c:35:19: error: no previous prototype for 'arch_get_vdso_data' [-Werror=missing-prototypes]

Move the prototype out of the #ifdef block to reliably turn off that
warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230517131102.934196-15-arnd@kernel.org

find_timens_vvar_page() is not architecture-specific, as can be seen from
how all five per-architecture versions of it are the same.

(arm64, powerpc and riscv are exactly the same; x86 and s390 have two
characters difference inside a comment, less blank lines, and mark the
!CONFIG_TIME_NS version as inline.)

Refactor the five copies into a central copy in kernel/time/namespace.c.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20221130115320.2918447-1-jannh@google.com

Pull misc fixes from Christian Brauner:
 "This contains several fixes which felt worth being combined into a
  single branch:

   - Use put_nsproxy() instead of open-coding it switch_task_namespaces()

   - Kirill's work to unify lifecycle management for all namespaces. The
     lifetime counters are used identically for all namespaces types.
     Namespaces may of course have additional unrelated counters and
     these are not altered. This work allows us to unify the type of the
     counters and reduces maintenance cost by moving the counter in one
     place and indicating that basic lifetime management is identical
     for all namespaces.

   - Peilin's fix adding three byte padding to Dmitry's
     PTRACE_GET_SYSCALL_INFO uapi struct to prevent an info leak.

   - Two smal patches to convert from the /* fall through */ comment
     annotation to the fallthrough keyword annotation which I had taken
     into my branch and into -next before df561f6688fe ("treewide: Use
     fallthrough pseudo-keyword") made it upstream which fixed this
     tree-wide.

     Since I didn't want to invalidate all testing for other commits I
     didn't rebase and kept them"

* tag 'fixes-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  nsproxy: use put_nsproxy() in switch_task_namespaces()
  sys: Convert to the new fallthrough notation
  signal: Convert to the new fallthrough notation
  time: Use generic ns_common::count
  cgroup: Use generic ns_common::count
  mnt: Use generic ns_common::count
  user: Use generic ns_common::count
  pid: Use generic ns_common::count
  ipc: Use generic ns_common::count
  uts: Use generic ns_common::count
  net: Use generic ns_common::count
  ns: Add a common refcount into ns_common
  ptrace: Prevent kernel-infoleak in ptrace_get_syscall_info()

timens_on_fork() always return 0, and maybe not
need to judge the return value in copy_namespaces().

So make timens_on_fork() return nothing and do not
judge its return val in copy_namespaces().

Signed-off-by: Hui Su <sh_def@163.com>
Link: https://lore.kernel.org/r/20201117161750.GA45121@rlk
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Provide functions for time_namespace to subtract the boottime offset
from a timespec64 as well as to apply the boottime offset to u64 types in
nanoseconds.

Signed-off-by: Michael Weiß <michael.weiss@aisec.fraunhofer.de>
Reviewed-by: Andrei Vagin <avagin@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20201027204258.7869-2-michael.weiss@aisec.fraunhofer.de