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05 April 2024, 19:05:47 UTC
Revision 46011e6ea39235e4aca656673c500eac81a07a17 authored by David Daney on 04 August 2015, 00:48:43 UTC, committed by Ralf Baechle on 05 August 2015, 09:11:10 UTC 
MIPS: Make set_pte() SMP safe.
 
On MIPS the GLOBAL bit of the PTE must have the same value in any
aligned pair of PTEs.  These pairs of PTEs are referred to as
"buddies".  In a SMP system is is possible for two CPUs to be calling
set_pte() on adjacent PTEs at the same time.  There is a race between
setting the PTE and a different CPU setting the GLOBAL bit in its
buddy PTE.

This race can be observed when multiple CPUs are executing
vmap()/vfree() at the same time.

Make setting the buddy PTE's GLOBAL bit an atomic operation to close
the race condition.

The case of CONFIG_64BIT_PHYS_ADDR && CONFIG_CPU_MIPS32 is *not*
handled.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: <stable@vger.kernel.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10835/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
1 parent a450475
History
Tip revision: 46011e6ea39235e4aca656673c500eac81a07a17 authored by David Daney on 04 August 2015, 00:48:43 UTC
MIPS: Make set_pte() SMP safe.
Tip revision: 46011e6
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