Len Brown <lenb@xxxxxxxxxx> wrote: > From: Huang Ying <ying.huang@xxxxxxxxx> > > cmpxchg() is widely used by lockless code, including NMI-safe lockless > code. But on some architectures, the cmpxchg() implementation is not > NMI-safe, on these architectures the lockless code may need a > spin_trylock_irqsave() based implementation. > > This patch adds a Kconfig option: ARCH_HAVE_NMI_SAFE_CMPXCHG, so that > NMI-safe lockless code can depend on it or provide different > implementation according to it. > > On many architectures, cmpxchg is only NMI-safe for several specific > operand sizes. So, ARCH_HAVE_NMI_SAFE_CMPXCHG define in this patch > only guarantees cmpxchg is NMI-safe for sizeof(unsigned long). > > Signed-off-by: Huang Ying <ying.huang@xxxxxxxxx> > Acked-by: Mike Frysinger <vapier@xxxxxxxxxx> > Acked-by: Paul Mundt <lethal@xxxxxxxxxxxx> > Acked-by: Hans-Christian Egtvedt <hans-christian.egtvedt@xxxxxxxxx> > Acked-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> > Acked-by: Chris Metcalf <cmetcalf@xxxxxxxxxx> > CC: Richard Henderson <rth@xxxxxxxxxxx> > CC: Mikael Starvik <starvik@xxxxxxxx> > CC: David Howells <dhowells@xxxxxxxxxx> > CC: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx> > CC: Tony Luck <tony.luck@xxxxxxxxx> > CC: Hirokazu Takata <takata@xxxxxxxxxxxxxx> > CC: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> > CC: Michal Simek <monstr@xxxxxxxxx> > CC: Ralf Baechle <ralf@xxxxxxxxxxxxxx> > CC: Kyle McMartin <kyle@xxxxxxxxxxx> > CC: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> > CC: Chen Liqin <liqin.chen@xxxxxxxxxxxxx> > CC: "David S. Miller" <davem@xxxxxxxxxxxxx> > CC: Ingo Molnar <mingo@xxxxxxxxxx> > CC: Chris Zankel <chris@xxxxxxxxxx> > Signed-off-by: Len Brown <len.brown@xxxxxxxxx> Acked-by: David Howells <dhowells@xxxxxxxxxx> [FRV] -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
