[PATCH] log machine check errors

Linas Vepstas linas at austin.ibm.com
Fri Aug 27 07:52:26 EST 2004

On Thu, Aug 26, 2004 at 01:39:02PM -0700, Dave Hansen was heard to remark:
> On Thu, 2004-08-26 at 05:36, Jake Moilanen wrote:
> > IIRC check-exception expects that the buffer not cross an
> > LMB.  One way we can guarantee it is to make sure it also doesn't cross
> > a page boundary, hence the page alignment.
> Is the buffer guaranteed to never be larger than a page?  (I know it's
> only 2048 bytes now)

Actually, there is one thing we probably should do, and that's to
change the buffer to 4K now, so that if/when firmware moves to 4K,
older kernels (i.e. the ones we are creating now) will continue
to work correctly.

We already hit this with the rhel3 2.4 kernels on power5 ... we forgot
to upgrade from 1K to 2K and now all the logs are being truncated, and
redhat doesn't want to patch this late in the game ...

So, with that argument in hand, will the maintainers accept the
following patch?

Signed-off-by: Linas Vepstas <linas at linas.org>

===== include/asm-ppc64/rtas.h 1.21 vs edited =====
--- 1.21/include/asm-ppc64/rtas.h       Wed Aug 25 15:09:24 2004
+++ edited/include/asm-ppc64/rtas.h     Thu Aug 26 16:48:33 2004
@@ -199,7 +199,7 @@


-#define RTAS_ERROR_LOG_MAX 2048
+#define RTAS_ERROR_LOG_MAX 4096

 /** Return the firmware-specified size of the error log buffer
  *  for all rtas calls that require an error buffer argument.

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