We have several places across the kernel where we want to access another
task's syscall arguments, such as ptrace(2), seccomp(2), etc., by making
a call to syscall_get_arguments().

This works for register arguments right away by accessing the task's
`regs' member of `struct pt_regs', however for stack arguments seen with
32-bit/o32 kernels things are more complicated.  Technically they ought
to be obtained from the user stack with calls to an access_remote_vm(),
but we have an easier way available already.

So as to be able to access syscall stack arguments as regular function
arguments following the MIPS calling convention we copy them over from
the user stack to the kernel stack in arch/mips/kernel/scall32-o32.S, in
handle_sys(), to the current stack frame's outgoing argument space at
the top of the stack, which is where the handler called expects to see
its incoming arguments.  This area is also pointed at by the `pt_regs'
pointer obtained by task_pt_regs().

Make the o32 stack argument space a proper member of `struct pt_regs'
then, by renaming the existing member from `pad0' to `args' and using
generated offsets to access the space.  No functional change though.

With the change in place the o32 kernel stack frame layout at the entry
to a syscall handler invoked by handle_sys() is therefore as follows:

$sp + 68 -> |         ...         | <- pt_regs.regs[9]
            +---------------------+
$sp + 64 -> |         $t0         | <- pt_regs.regs[8]
            +---------------------+
$sp + 60 -> |   $a3/argument #4   | <- pt_regs.regs[7]
            +---------------------+
$sp + 56 -> |   $a2/argument #3   | <- pt_regs.regs[6]
            +---------------------+
$sp + 52 -> |   $a1/argument #2   | <- pt_regs.regs[5]
            +---------------------+
$sp + 48 -> |   $a0/argument #1   | <- pt_regs.regs[4]
            +---------------------+
$sp + 44 -> |         $v1         | <- pt_regs.regs[3]
            +---------------------+
$sp + 40 -> |         $v0         | <- pt_regs.regs[2]
            +---------------------+
$sp + 36 -> |         $at         | <- pt_regs.regs[1]
            +---------------------+
$sp + 32 -> |        $zero        | <- pt_regs.regs[0]
            +---------------------+
$sp + 28 -> |  stack argument #8  | <- pt_regs.args[7]
            +---------------------+
$sp + 24 -> |  stack argument #7  | <- pt_regs.args[6]
            +---------------------+
$sp + 20 -> |  stack argument #6  | <- pt_regs.args[5]
            +---------------------+
$sp + 16 -> |  stack argument #5  | <- pt_regs.args[4]
            +---------------------+
$sp + 12 -> | psABI space for $a3 | <- pt_regs.args[3]
            +---------------------+
$sp +  8 -> | psABI space for $a2 | <- pt_regs.args[2]
            +---------------------+
$sp +  4 -> | psABI space for $a1 | <- pt_regs.args[1]
            +---------------------+
$sp +  0 -> | psABI space for $a0 | <- pt_regs.args[0]
            +---------------------+

holding user data received and with the first 4 frame slots reserved by
the psABI for the compiler to spill the incoming arguments from $a0-$a3
registers (which it sometimes does according to its needs) and the next
4 frame slots designated by the psABI for any stack function arguments
that follow.  This data is also available for other tasks to peek/poke
at as reqired and where permitted.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Pull MIPS fix from Thomas Bogendoerfer:
 "Revert commit breaking sysv ipc for o32 ABI"

* tag 'mips_6.14_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  Revert "mips: fix shmctl/semctl/msgctl syscall for o32"

This reverts commit bc7584e009c39375294794f7ca751a6b2622c425.

The split IPC system calls for o32 have been introduced with modern
version only. Changing this breaks ABI.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Pull MIPS updates from Thomas Bogendoerfer:
 "Cleanups and fixes"

* tag 'mips_6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  MIPS: pci-legacy: Override pci_address_to_pio
  MIPS: Loongson64: env: Use str_on_off() helper in prom_lefi_init_env()
  MIPS: migrate to generic rule for built-in DTBs
  mips: fix shmctl/semctl/msgctl syscall for o32
  mips/math-emu: fix emulation of the prefx instruction
  MIPS: Loongson: Add comments for interface_info
  MIPS: Loongson64: remove ROM Size unit in boardinfo
  MIPS: traps: Use str_enabled_disabled() in parity_protection_init()
  MIPS: ftrace: Declare ftrace_get_parent_ra_addr() as static
  Revert "MIPS: csrc-r4k: Select HAVE_UNSTABLE_SCHED_CLOCK if SMP && 64BIT"
  MIPS: Fix the wrong format specifier
  MIPS: Add a blank line after __HEAD
  MIPS: kernel: Rename read/write_c0_ecc to read/writec0_errctl

Before SLUB initialization, various subsystems used memblock_alloc to
allocate memory.  In most cases, when memory allocation fails, an
immediate panic is required.  To simplify this behavior and reduce
repetitive checks, introduce `memblock_alloc_or_panic`.  This function
ensures that memory allocation failures result in a panic automatically,
improving code readability and consistency across subsystems that require
this behavior.

[guoweikang.kernel@gmail.com: arch/s390: save_area_alloc default failure behavior changed to panic]
  Link: https://lkml.kernel.org/r/20250109033136.2845676-1-guoweikang.kernel@gmail.com
  Link: https://lore.kernel.org/lkml/Z2fknmnNtiZbCc7x@kernel.org/
Link: https://lkml.kernel.org/r/20250102072528.650926-1-guoweikang.kernel@gmail.com
Signed-off-by: Guo Weikang <guoweikang.kernel@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>	[m68k]
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>	[s390]
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "mm: update mips to use do_mmap(), make mmap_region()
internal".

Currently the only user of mmap_region() outside of the memory management
code is the MIPS VDSO implementation.

This uses mmap_region() to map a 'delay slot emulation page' at the top of
the stack which is read-only and executable.

This mapping requires that an already-acquired mmap write lock is utilised
and that uffd and populate logic is ignored. This rules out vm_mmap(),
however do_mmap() fits the bill.

Adapt this code to use do_mmap() and then once done, make mmap_region()
internal and userland testable, and avoid any other uses of mmap_region(),
which is absolutely and strictly an internal mm function which bypasses a
great number of checks and logic.


This patch (of 2):

mmap_region() is an internal memory management implementation detail that
is not intended to be used outside of the memory management subsystem.

Map the delay slot emulation page using do_mmap() which makes use of the
already-held mmap write lock and bypasses unneeded populate and
userfaultfd logic.

This should have the precise same behaviour as the existing logic.

Link: https://lkml.kernel.org/r/cover.1735819274.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/ef076e381570f709e5c2c142dc030ec5b3309a0e.1735819274.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Jann Horn <jannh@google.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

The commit 275f22148e87 ("ipc: rename old-style shmctl/semctl/msgctl
syscalls") switched various architectures to use sys_old_*ctl() with
ipc_parse_version, including mips n32/n64. However, for mips o32, commit
0d6040d46817 ("arch: add split IPC system calls where needed") added
separate IPC syscalls without properly using the old-style handlers.

This causes applications using uClibc-ng to fail with -EINVAL when
calling semctl/shmctl/msgctl with IPC_64 flag, as uClibc-ng uses the
syscall numbers from kernel headers to determine whether to use the IPC
multiplexer or split syscalls. In contrast, glibc is unaffected as it
uses a unified feature test macro __ASSUME_DIRECT_SYSVIPC_SYSCALLS
(disabled for mips-o32) to make this decision.

Fix this by switching the o32 ABI entries for semctl, shmctl and msgctl
to use the old-style handlers, matching the behavior of other
architectures and fixing compatibility with uClibc-ng.

Signed-off-by: Ism Hong <ism.hong@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Remove hard-coded strings by using the str_enabled_disabled() helper
function.

Use pr_info() instead of printk(KERN_INFO) to silence multiple
checkpatch warnings.

Suggested-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Declare ftrace_get_parent_ra_addr() as static to suppress clang
compiler warning that 'no previous prototype'. This function is
not intended to be called from other parts.

Fix follow error with clang-19:

arch/mips/kernel/ftrace.c:251:15: error: no previous prototype for function 'ftrace_get_parent_ra_addr' [-Werror,-Wmissing-prototypes]
  251 | unsigned long ftrace_get_parent_ra_addr(unsigned long self_ra, unsigned long
      |               ^
arch/mips/kernel/ftrace.c:251:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
  251 | unsigned long ftrace_get_parent_ra_addr(unsigned long self_ra, unsigned long
      | ^
      | static
1 error generated.

Signed-off-by: WangYuli <wangyuli@uniontech.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Make a minor change to eliminate a static checker warning. The type
of cpu is unsigned int, so the correct format specifier should be
%u instead of %d.

Signed-off-by: liujing <liujing@cmss.chinamobile.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>