[LTP] [PATCH 2/8] Hugetlb: Migrating libhugetlbfs huge_at_4GB_normal_below

[Tarun Sahu]

Hi Richard,
Thanks for reviewing it.
On Dec 05 2022, Richard Palethorpe wrote:
> Hello,
> 
> Tarun Sahu <tsahu@linux.ibm.com> writes:
> 
> > Migrating the libhugetlbfs/testcases/huge_at_4GB_normal_below.c test
> >
> > Test Description: Designed to pick up a bug on ppc64 where
> > touches_hugepage_high_range() falsely reported true for ranges reaching
> > below 4GB
> >
> > Signed-off-by: Tarun Sahu <tsahu@linux.ibm.com>
> > ---
> >  runtest/hugetlb                               |   1 +
> >  testcases/kernel/mem/.gitignore               |   1 +
> >  .../kernel/mem/hugetlb/hugemmap/hugemmap13.c  | 122 ++++++++++++++++++
> >  3 files changed, 124 insertions(+)
> >  create mode 100644 testcases/kernel/mem/hugetlb/hugemmap/hugemmap13.c
> >
> > diff --git a/runtest/hugetlb b/runtest/hugetlb
> > index 4c16e1e7c..2029ee4b3 100644
> > --- a/runtest/hugetlb
> > +++ b/runtest/hugetlb
> > @@ -14,6 +14,7 @@ hugemmap09 hugemmap09
> >  hugemmap10 hugemmap10
> >  hugemmap11 hugemmap11
> >  hugemmap12 hugemmap12
> > +hugemmap13 hugemmap13
> >  hugemmap05_1 hugemmap05 -m
> >  hugemmap05_2 hugemmap05 -s
> >  hugemmap05_3 hugemmap05 -s -m
> > diff --git a/testcases/kernel/mem/.gitignore b/testcases/kernel/mem/.gitignore
> > index adea760c7..5955ed613 100644
> > --- a/testcases/kernel/mem/.gitignore
> > +++ b/testcases/kernel/mem/.gitignore
> > @@ -13,6 +13,7 @@
> >  /hugetlb/hugemmap/hugemmap10
> >  /hugetlb/hugemmap/hugemmap11
> >  /hugetlb/hugemmap/hugemmap12
> > +/hugetlb/hugemmap/hugemmap13
> >  /hugetlb/hugeshmat/hugeshmat01
> >  /hugetlb/hugeshmat/hugeshmat02
> >  /hugetlb/hugeshmat/hugeshmat03
> > diff --git a/testcases/kernel/mem/hugetlb/hugemmap/hugemmap13.c b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap13.c
> > new file mode 100644
> > index 000000000..84a84e074
> > --- /dev/null
> > +++ b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap13.c
> > @@ -0,0 +1,122 @@
> > +// SPDX-License-Identifier: LGPL-2.1-or-later
> > +/*
> > + * Copyright (C) 2005-2006 David Gibson & Adam Litke, IBM Corporation.
> > + * Author: David Gibson & Adam Litke
> > + */
> > +
> > +/*\
> > + * [Description]
> > + *
> > + * Designed to pick up a bug on ppc64 where touches_hugepage_high_range()
> > + * falsely reported true for ranges reaching below 4GB
> 
> Hhmm seems like the macro no longer exists. This isn't a great test
> description.
> 
> This appers to be the fix for the bug mentioned:
> https://lkml.org/lkml/2005/11/23/540
> 
> Maybe we could add to this that the test creates a hugepage just above
> the 32bit memory space and a normal page below it. That on old kernels
> this would trigger a bug caused by an off-by-one error.
> 
Yeah Agree, Will update it in v2.
> -- 
> Thank you,
> Richard.
> 
> -- 
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