From: Chris Metcalf <cmetcalf@tilera.com>
Date: Tue, 9 Apr 2013 16:33:07 +0000 (-0400)
Subject: tile: comment assumption about __insn_mtspr for <asm/irqflags.h>
X-Git-Tag: v3.9-rc7~36
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3e2e0d2c222bdf5bafd722dec1618fa6073ef372;p=pandora-kernel.git

tile: comment assumption about __insn_mtspr for <asm/irqflags.h>

The arch_local_irq_save(), etc., routines are required to function
as compiler barriers.  They do, but it's subtle and requires knowing
that the gcc builtin __insn_mtspr() is marked as a memory clobber.
Provide a comment explaining the assumption.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
[ This came about from me wondering about the synchronization rules of
  __insn_mtspr()   - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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