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mn10300: Fix crash just after starting userspace on !CONFIG_PREEMPT
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The mn10300 kernel crashes just after starting userspace programs, if
CONFIG_PREEMPT is disabled:

  Freeing unused kernel memory: 96K (90286000 - 9029e000)
  MISALIGN: 97c33ff9: unsupported instruction f
  MISALIGN: 97c33ff9: unsupported instruction f
  MISALIGN: 97c33ff9: unsupported instruction f
  :

This fixes the problem that was introduced by commit d17fc23
("MN10300: Enable IRQs more in system call exit work path").

Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Akira Takeuchi authored and Linus Torvalds committed Sep 10, 2013
1 parent 31f7c3a commit 3da06ed
Showing 1 changed file with 4 additions and 2 deletions.
6 changes: 4 additions & 2 deletions arch/mn10300/kernel/entry.S
Original file line number Diff line number Diff line change
Expand Up @@ -171,10 +171,10 @@ ret_from_intr:
mov (REG_EPSW,fp),d0 # need to deliver signals before
# returning to userspace
and EPSW_nSL,d0
beq resume_kernel # returning to supervisor mode
bne resume_userspace # returning to userspace

#ifdef CONFIG_PREEMPT
ENTRY(resume_kernel)
resume_kernel:
LOCAL_IRQ_DISABLE
mov (TI_preempt_count,a2),d0 # non-zero preempt_count ?
cmp 0,d0
Expand All @@ -189,6 +189,8 @@ need_resched:
bne restore_all
call preempt_schedule_irq[],0
jmp need_resched
#else
jmp resume_kernel
#endif


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