Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

From: Petr Mladek
Date: Fri Dec 11 2015 - 07:42:11 EST


On Fri 2015-12-11 12:10:02, Geert Uytterhoeven wrote:
> On Wed, Dec 9, 2015 at 2:21 PM, Petr Mladek <pmladek@xxxxxxxx> wrote:
> > --- a/init/Kconfig
> > +++ b/init/Kconfig
> > @@ -866,6 +866,28 @@ config LOG_CPU_MAX_BUF_SHIFT
> > 13 => 8 KB for each CPU
> > 12 => 4 KB for each CPU
> >
> > +config NMI_LOG_BUF_SHIFT
> > + int "Temporary per-CPU NMI log buffer size (12 => 4KB, 13 => 8KB)"
> > + range 10 21
> > + default 13
> > + depends on PRINTK && HAVE_NMI
>
> Symbol NMI_LOG_BUF_SHIFT does not exist if its dependencies are not met.

Åh, the NMI buffer is enabled on arm via NEED_PRINTK_NMI.

The buffer is compiled when CONFIG_PRINTK_NMI is defined. I am going
to fix it the following way:


diff --git a/init/Kconfig b/init/Kconfig
index efcff25a112d..61cfd96a3c96 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -870,7 +870,7 @@ config NMI_LOG_BUF_SHIFT
int "Temporary per-CPU NMI log buffer size (12 => 4KB, 13 => 8KB)"
range 10 21
default 13
- depends on PRINTK && HAVE_NMI
+ depends on PRINTK_NMI
help
Select the size of a per-CPU buffer where NMI messages are temporary
stored. They are copied to the main log buffer in a safe context


Thanks a lot for report,
Petr
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