[ARM] Fix ASID version switch

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Close a hole in the ASID version switch, particularly the following
scenario:

CPU0 MM PID			CPU1 MM PID
	idle
				  A	pid(A)
				  A	idle(lazy tlb)
		* new asid version triggered by B *
  B	pid(B)
  A	pid(A)
		* MM A gets new asid version *
  A	idle(lazy tlb)
				  A	pid(A)
		* CPU1 doesn't see the new ASID *

The result is that CPU1 continues running with the hardware set
for the original (stale) ASID value, but mm->context.id contains
the new ASID value.  The result is that the next MM fault on CPU1
updates the page table entries, but flush_tlb_page() fails due to
wrong ASID.

There is a related case with a threaded application is allocated
a new ASID on one CPU while another of its threads is running on
some different CPU.  This scenario is not fixed by this commit.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

...

This commit is contained in:

Russell King 2007-05-08 20:03:09 +01:00 • committed by Russell King

parent 08fdffd4cf

commit 8678c1f042

2 changed files with 11 additions and 7 deletions

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8

include/asm-arm/mmu_context.h

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