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authorDavid S. Miller <davem@davemloft.net>2010-04-13 01:50:43 -0700
committerDavid S. Miller <davem@davemloft.net>2010-04-13 01:50:43 -0700
commitc011f80ba0912486fe51dd2b3f71d9b33a151188 (patch)
treef133e1b698f5a0eaca251bcdcc5a4f6397aa59d7 /arch/sparc/include
parent9343af084c7e8911897b0883042ee690cee3aaef (diff)
downloadlinux-linaro-c011f80ba0912486fe51dd2b3f71d9b33a151188.tar.gz
sparc64: Add some more commentary to __raw_local_irq_save()
Suggested by Peter Zijlstra Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc/include')
-rw-r--r--arch/sparc/include/asm/irqflags_64.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/sparc/include/asm/irqflags_64.h b/arch/sparc/include/asm/irqflags_64.h
index a16e94c4b14..bfa1ea45b4c 100644
--- a/arch/sparc/include/asm/irqflags_64.h
+++ b/arch/sparc/include/asm/irqflags_64.h
@@ -80,6 +80,13 @@ static inline unsigned long __raw_local_irq_save(void)
/* Disable interrupts to PIL_NORMAL_MAX unless we already
* are using PIL_NMI, in which case PIL_NMI is retained.
+ *
+ * The only values we ever program into the %pil are 0,
+ * PIL_NORMAL_MAX and PIL_NMI.
+ *
+ * Since PIL_NMI is the largest %pil value and all bits are
+ * set in it (0xf), it doesn't matter what PIL_NORMAL_MAX
+ * actually is.
*/
__asm__ __volatile__(
"rdpr %%pil, %0\n\t"