kernel.git/arch/m68k/kernel, branch linux-4.19.y

m68k: mvme147: Reinstate early console

2024-12-05T09:59:30Z

[ 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"

2024-12-05T09:59:30Z

[ 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 spinlock race in kernel thread creation

2024-06-16T11:23:28Z

[ 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

2023-09-23T08:47:57Z

[ 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()

2023-08-08T17:49:17Z

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

m68k: Move signal frame following exception on 68020/030

2023-05-30T11:42:13Z

commit b845b574f86dcb6a70dfa698aa87a237b0878d2a upstream. On 68030/020, an instruction such as, moveml %a2-%a3/%a5,%sp@- may cause a stack page fault during instruction execution (i.e. not at an instruction boundary) and produce a format 0xB exception frame. In this situation, the value of USP will be unreliable. If a signal is to be delivered following the exception, this USP value is used to calculate the location for a signal frame. This can result in a corrupted user stack. The corruption was detected in dash (actually in glibc) where it showed up as an intermittent "stack smashing detected" message and crash following signal delivery for SIGCHLD. It was hard to reproduce that failure because delivery of the signal raced with the page fault and because the kernel places an unpredictable gap of up to 7 bytes between the USP and the signal frame. A format 0xB exception frame can be produced by a bus error or an address error. The 68030 Users Manual says that address errors occur immediately upon detection during instruction prefetch. The instruction pipeline allows prefetch to overlap with other instructions, which means an address error can arise during the execution of a different instruction. So it seems likely that this patch may help in the address error case also. Reported-and-tested-by: Stan Johnson Link: https://lore.kernel.org/all/CAMuHMdW3yD22_ApemzW_6me3adq6A458u1_F0v-1EYwK_62jPA@mail.gmail.com/ Cc: Michael Schmitz Cc: Andreas Schwab Cc: stable@vger.kernel.org Co-developed-by: Michael Schmitz Signed-off-by: Michael Schmitz Signed-off-by: Finn Thain Reviewed-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/9e66262a754fcba50208aa424188896cc52a1dd1.1683365892.git.fthain@linux-m68k.org Signed-off-by: Geert Uytterhoeven Signed-off-by: Greg Kroah-Hartman

m68k: Only force 030 bus error if PC not in exception table

2023-04-05T09:15:36Z

[ Upstream commit e36a82bebbf7da814530d5a179bef9df5934b717 ] __get_kernel_nofault() does copy data in supervisor mode when forcing a task backtrace log through /proc/sysrq_trigger. This is expected cause a bus error exception on e.g. NULL pointer dereferencing when logging a kernel task has no workqueue associated. This bus error ought to be ignored. Our 030 bus error handler is ill equipped to deal with this: Whenever ssw indicates a kernel mode access on a data fault, we don't even attempt to handle the fault and instead always send a SEGV signal (or panic). As a result, the check for exception handling at the fault PC (buried in send_sig_fault() which gets called from do_page_fault() eventually) is never used. In contrast, both 040 and 060 access error handlers do not care whether a fault happened on supervisor mode access, and will call do_page_fault() on those, ultimately honoring the exception table. Add a check in bus_error030 to call do_page_fault() in case we do have an entry for the fault PC in our exception table. I had attempted a fix for this earlier in 2019 that did rely on testing pagefault_disabled() (see link below) to achieve the same thing, but this patch should be more generic. Tested on 030 Atari Falcon. Reported-by: Eero Tamminen Link: https://lore.kernel.org/r/alpine.LNX.2.21.1904091023540.25@nippy.intranet Link: https://lore.kernel.org/r/63130691-1984-c423-c1f2-73bfd8d3dcd3@gmail.com Signed-off-by: Michael Schmitz Reviewed-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/20230301021107.26307-1-schmitzmic@gmail.com Signed-off-by: Geert Uytterhoeven Signed-off-by: Sasha Levin

m68k: Check syscall_trace_enter() return code

2023-03-11T15:31:46Z

[ Upstream commit 2ca8a1de4437f21562e57f9ac123914747a8e7a1 ] Check return code of syscall_trace_enter(), and skip syscall if -1. Return code will be left at what had been set by ptrace or seccomp (in regs->d0). No regression seen in testing with strace on ARAnyM. Signed-off-by: Michael Schmitz Reviewed-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/20230112035529.13521-2-schmitzmic@gmail.com Signed-off-by: Geert Uytterhoeven Signed-off-by: Sasha Levin

exit: Add and use make_task_dead.

2023-02-06T06:49:45Z

commit 0e25498f8cd43c1b5aa327f373dd094e9a006da7 upstream. There are two big uses of do_exit. The first is it's design use to be the guts of the exit(2) system call. The second use is to terminate a task after something catastrophic has happened like a NULL pointer in kernel code. Add a function make_task_dead that is initialy exactly the same as do_exit to cover the cases where do_exit is called to handle catastrophic failure. In time this can probably be reduced to just a light wrapper around do_task_dead. For now keep it exactly the same so that there will be no behavioral differences introducing this new concept. Replace all of the uses of do_exit that use it for catastraphic task cleanup with make_task_dead to make it clear what the code is doing. As part of this rename rewind_stack_do_exit rewind_stack_and_make_dead. Signed-off-by: "Eric W. Biederman" Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman

m68k: Handle arrivals of multiple signals correctly

2021-10-17T08:19:49Z

[ Upstream commit 4bb0bd81ce5e97092dfda6a106d414b703ec0ee8 ] When we have several pending signals, have entered with the kernel with large exception frame *and* have already built at least one sigframe, regs->stkadj is going to be non-zero and regs->format/sr/pc are going to be junk - the real values are in shifted exception stack frame we'd built when putting together the first sigframe. If that happens, subsequent sigframes are going to be garbage. Not hard to fix - just need to find the "adjusted" frame first and look for format/vector/sr/pc in it. Signed-off-by: Al Viro Tested-by: Michael Schmitz Reviewed-by: Michael Schmitz Tested-by: Finn Thain Link: https://lore.kernel.org/r/YP2dBIAPTaVvHiZ6@zeniv-ca.linux.org.uk Signed-off-by: Geert Uytterhoeven Signed-off-by: Sasha Levin