linux.git/arch/m68k/kernel, branch v5.10.258

m68k: Fix lost column on framebuffer debug console

2025-08-28T14:22:48+00:00

commit 210a1ce8ed4391b64a888b3fb4b5611a13f5ccc7 upstream.

Move the cursor position rightward after rendering the character,
not before. This avoids complications that arise when the recursive
console_putc call has to wrap the line and/or scroll the display.
This also fixes the linewrap bug that crops off the rightmost column.

When the cursor is at the bottom of the display, a linefeed will not
move the cursor position further downward. Instead, the display scrolls
upward. Avoid the repeated add/subtract sequence by way of a single
subtraction at the initialization of console_struct_num_rows.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Finn Thain 
Tested-by: Stan Johnson 
Reviewed-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/9d4e8c68a456d5f2bc254ac6f87a472d066ebd5e.1743115195.git.fthain@linux-m68k.org
Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Greg Kroah-Hartman

m68k: Don't unregister boot console needlessly

2025-08-28T14:22:32+00:00

[ Upstream commit 83f672a7f69ec38b1bbb27221e342937f68c11c7 ]

When MACH_IS_MVME147, the boot console calls mvme147_scc_write() to
generate console output. That will continue to work even after
debug_cons_nputs() becomes unavailable so there's no need to
unregister the boot console.

Take the opportunity to remove a repeated MACH_IS_* test. Use the
actual .write method (instead of a wrapper) and test that pointer
instead. This means adding an unused parameter to debug_cons_nputs() for
consistency with the struct console API.

early_printk.c is only built when CONFIG_EARLY_PRINTK=y. As of late,
head.S is only built when CONFIG_MMU_MOTOROLA=y. So let the former symbol
depend on the latter, to obviate some ifdef conditionals.

Cc: Daniel Palmer 
Fixes: 077b33b9e283 ("m68k: mvme147: Reinstate early console")
Signed-off-by: Finn Thain 
Reviewed-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/d1d4328e5aa9a87bd8352529ce62b767731c0530.1743467205.git.fthain@linux-m68k.org
Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Sasha Levin

signal/m68k: Use force_sigsegv(SIGSEGV) in fpsp040_die

2025-02-01T17:22:33+00:00

commit a3616a3c02722d1edb95acc7fceade242f6553ba upstream.

In the fpsp040 code when copyin or copyout fails call
force_sigsegv(SIGSEGV) instead of do_exit(SIGSEGV).

This solves a couple of problems.  Because do_exit embeds the ptrace
stop PTRACE_EVENT_EXIT a complete stack frame needs to be present for
that to work correctly.  There is always the information needed for a
ptrace stop where get_signal is called.  So exiting with a signal
solves the ptrace issue.

Further exiting with a signal ensures that all of the threads in a
process are killed not just the thread that malfunctioned.  Which
avoids confusing userspace.

To make force_sigsegv(SIGSEGV) work in fpsp040_die modify the code to
save all of the registers and jump to ret_from_exception (which
ultimately calls get_signal) after fpsp040_die returns.

v2: Updated the branches to use gas's pseudo ops that automatically
    calculate the best branch instruction to use for the purpose.

v1: https://lkml.kernel.org/r/87a6m8kgtx.fsf_-_@disp2133
Link: https://lkml.kernel.org/r/87tukghjfs.fsf_-_@disp2133
Acked-by: Geert Uytterhoeven 
Signed-off-by: "Eric W. Biederman" 
Signed-off-by: Finn Thain 
Signed-off-by: Greg Kroah-Hartman

m68k: Update ->thread.esp0 before calling syscall_trace() in ret_from_signal

2025-02-01T17:22:32+00:00

commit 50e43a57334400668952f8e551c9d87d3ed2dfef upstream.

We get there when sigreturn has performed obscene acts on kernel stack;
in particular, the location of pt_regs has shifted.  We are about to call
syscall_trace(), which might stop for tracer.  If that happens, we'd better
have task_pt_regs() returning correct result...

Fucked-up-by: Al Viro 
Fixes: bd6f56a75bb2 ("m68k: Missing syscall_trace() on sigreturn")
Signed-off-by: Al Viro 
Tested-by: Michael Schmitz 
Reviewed-by: Michael Schmitz 
Tested-by: Finn Thain 
Link: https://lore.kernel.org/r/YP2dMWeV1LkHiOpr@zeniv-ca.linux.org.uk
Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Finn Thain 
Signed-off-by: Greg Kroah-Hartman

m68k: mvme147: Reinstate early console

2024-12-14T18:47:44+00:00

[ Upstream commit 077b33b9e2833ff25050d986178a2c4c4036cbac ]

Commit a38eaa07a0ce ("m68k/mvme147: config.c - Remove unused
functions"), removed the console functionality for the mvme147 instead
of wiring it up to an early console.  Put the console write function
back and wire it up like mvme16x does so it's possible to see Linux boot
on this fine hardware once more.

Fixes: a38eaa07a0ce ("m68k/mvme147: config.c - Remove unused functions")
Signed-off-by: Daniel Palmer 
Co-developed-by: Finn Thain 
Signed-off-by: Finn Thain 
Reviewed-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/a82e8f0068a8722996a0ccfe666abb5e0a5c120d.1730850684.git.fthain@linux-m68k.org
Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Sasha Levin

m68k: mvme16x: Add and use "mvme16x.h"

2024-12-14T18:47:43+00:00

[ Upstream commit dcec33c1fc4ab63983d93ffb0d82b68fc5775b88 ]

When building with W=1:

    arch/m68k/mvme16x/config.c:208:6: warning: no previous prototype for ‘mvme16x_cons_write’ [-Wmissing-prototypes]
      208 | void mvme16x_cons_write(struct console *co, const char *str, unsigned count)
	  |      ^~~~~~~~~~~~~~~~~~

Fix this by introducing a new header file "mvme16x.h" for holding the
prototypes of functions implemented in arch/m68k/mvme16x/.

Signed-off-by: Geert Uytterhoeven 
Acked-by: Arnd Bergmann 
Link: https://lore.kernel.org/r/6200cc3b26fad215c4524748af04692e38c5ecd2.1694613528.git.geert@linux-m68k.org
Stable-dep-of: 077b33b9e283 ("m68k: mvme147: Reinstate early console")
Signed-off-by: Sasha Levin

m68k: Fix kernel_clone_args.flags in m68k_clone()

2024-10-17T13:07:44+00:00

[ Upstream commit 09b3d870faa7bc3e96c0978ab3cf4e96e4b15571 ]

Stan Johnson recently reported a failure from the 'dump' command:

  DUMP: Date of this level 0 dump: Fri Aug  9 23:37:15 2024
  DUMP: Dumping /dev/sda (an unlisted file system) to /dev/null
  DUMP: Label: none
  DUMP: Writing 10 Kilobyte records
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 3595695 blocks.
  DUMP: Context save fork fails in parent 671

The dump program uses the clone syscall with the CLONE_IO flag, that is,
flags == 0x80000000. When that value is promoted from long int to u64 by
m68k_clone(), it undergoes sign-extension. The new value includes
CLONE_INTO_CGROUP so the validation in cgroup_css_set_fork() fails and
the syscall returns -EBADF. Avoid sign-extension by casting to u32.

Reported-by: Stan Johnson 
Closes: https://lists.debian.org/debian-68k/2024/08/msg00000.html
Fixes: 6aabc1facdb2 ("m68k: Implement copy_thread_tls()")
Signed-off-by: Finn Thain 
Reviewed-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/3463f1e5d4e95468dc9f3368f2b78ffa7b72199b.1723335149.git.fthain@linux-m68k.org
Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Sasha Levin

m68k: Fix spinlock race in kernel thread creation

2024-06-16T11:32:08+00:00

[ Upstream commit da89ce46f02470ef08f0f580755d14d547da59ed ]

Context switching does take care to retain the correct lock owner across
the switch from 'prev' to 'next' tasks.  This does rely on interrupts
remaining disabled for the entire duration of the switch.

This condition is guaranteed for normal process creation and context
switching between already running processes, because both 'prev' and
'next' already have interrupts disabled in their saved copies of the
status register.

The situation is different for newly created kernel threads.  The status
register is set to PS_S in copy_thread(), which does leave the IPL at 0.
Upon restoring the 'next' thread's status register in switch_to() aka
resume(), interrupts then become enabled prematurely.  resume() then
returns via ret_from_kernel_thread() and schedule_tail() where run queue
lock is released (see finish_task_switch() and finish_lock_switch()).

A timer interrupt calling scheduler_tick() before the lock is released
in finish_task_switch() will find the lock already taken, with the
current task as lock owner.  This causes a spinlock recursion warning as
reported by Guenter Roeck.

As far as I can ascertain, this race has been opened in commit
533e6903bea0 ("m68k: split ret_from_fork(), simplify kernel_thread()")
but I haven't done a detailed study of kernel history so it may well
predate that commit.

Interrupts cannot be disabled in the saved status register copy for
kernel threads (init will complain about interrupts disabled when
finally starting user space).  Disable interrupts temporarily when
switching the tasks' register sets in resume().

Note that a simple oriw 0x700,%sr after restoring sr is not enough here
- this leaves enough of a race for the 'spinlock recursion' warning to
still be observed.

Tested on ARAnyM and qemu (Quadra 800 emulation).

Fixes: 533e6903bea0 ("m68k: split ret_from_fork(), simplify kernel_thread()")
Reported-by: Guenter Roeck 
Closes: https://lore.kernel.org/all/07811b26-677c-4d05-aeb4-996cd880b789@roeck-us.net
Signed-off-by: Michael Schmitz 
Tested-by: Guenter Roeck 
Reviewed-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/r/20240411033631.16335-1-schmitzmic@gmail.com
Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Sasha Levin

m68k: Fix invalid .section syntax

2023-09-19T10:20:04+00:00

[ Upstream commit 922a9bd138101e3e5718f0f4d40dba68ef89bb43 ]

gas supports several different forms for .section for ELF targets,
including:
    .section NAME [, "FLAGS"[, @TYPE[,FLAG_SPECIFIC_ARGUMENTS]]]
and:
    .section "NAME"[, #FLAGS...]

In several places we use a mix of these two forms:
    .section NAME, #FLAGS...

A current development snapshot of binutils (2.40.50.20230611) treats
this mixed syntax as an error.

Change to consistently use:
    .section NAME, "FLAGS"
as is used elsewhere in the kernel.

Link: https://buildd.debian.org/status/fetch.php?pkg=linux&arch=m68k&ver=6.4%7Erc6-1%7Eexp1&stamp=1686907300&raw=1
Signed-off-by: Ben Hutchings 
Tested-by: Jan-Benedict Glaw 
Link: https://lore.kernel.org/r/ZIyBaueWT9jnTwRC@decadent.org.uk
Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Sasha Levin

m68k/cpu: Switch to arch_cpu_finalize_init()

2023-08-08T17:57:36+00:00

commit 9ceecc2589b9d7cef6b321339ed8de484eac4b20 upstream

check_bugs() is about to be phased out. Switch over to the new
arch_cpu_finalize_init() implementation.

No functional change.

Signed-off-by: Thomas Gleixner 
Acked-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/r/20230613224545.254342916@linutronix.de
Signed-off-by: Daniel Sneddon 
Signed-off-by: Greg Kroah-Hartman