kernel: local_irq_{save,restore}_nmi()
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From: Paul Mundt on 4 Jun 2010 01:10 On Fri, Apr 09, 2010 at 04:01:35PM -0700, David Miller wrote: > > Provide local_irq_{save,restore}_nmi() which will allow us to help > architectures that implement NMIs using IRQ priorities like SPARC64 > does. > > Sparc uses IRQ prio 15 for NMIs and implements local_irq_disable() as > disable <= 14. However if you do that while inside an NMI you re- > enable the NMI priority again, causing all kinds of fun. > > A more solid implementation would first check the disable level and > never lower it, however that is more costly and would slow down the > rest of the kernel for no particular reason. > > Therefore introduce local_irq_save_nmi() which can implement this > slower but more solid scheme and dis-allow local_irq_save() from NMI > context. > > Suggested-by: David Miller <davem(a)davemloft.net> > Signed-off-by: Peter Zijlstra <a.p.zijlstra(a)chello.nl> > Signed-off-by: David S. Miller <davem(a)davemloft.net> Are there any updates for this patch series? I would like to make use of this on SH as well, but it seems these haven't hit upstream yet. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Peter Zijlstra on 4 Jun 2010 03:40
On Fri, 2010-06-04 at 14:03 +0900, Paul Mundt wrote: > On Fri, Apr 09, 2010 at 04:01:35PM -0700, David Miller wrote: > > > > Provide local_irq_{save,restore}_nmi() which will allow us to help > > architectures that implement NMIs using IRQ priorities like SPARC64 > > does. > > > > Sparc uses IRQ prio 15 for NMIs and implements local_irq_disable() as > > disable <= 14. However if you do that while inside an NMI you re- > > enable the NMI priority again, causing all kinds of fun. > > > > A more solid implementation would first check the disable level and > > never lower it, however that is more costly and would slow down the > > rest of the kernel for no particular reason. > > > > Therefore introduce local_irq_save_nmi() which can implement this > > slower but more solid scheme and dis-allow local_irq_save() from NMI > > context. > > > > Suggested-by: David Miller <davem(a)davemloft.net> > > Signed-off-by: Peter Zijlstra <a.p.zijlstra(a)chello.nl> > > Signed-off-by: David S. Miller <davem(a)davemloft.net> > > Are there any updates for this patch series? I would like to make use of > this on SH as well, but it seems these haven't hit upstream yet. Dave found a better solution, see: b4f4372f96e0573d752d9e45beda02fabf716cc8 0c25e9e6cbe7b233bb91d14d0e2c258bf8e6ec83 c011f80ba0912486fe51dd2b3f71d9b33a151188 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |