GCC 15 reports the below false positive '-Wmaybe-uninitialized' warning
in vphn_unpack_associativity() when building the powerpc selftests.
# make -C tools/testing/selftests TARGETS="powerpc"
[...]
CC test-vphn
In file included from test-vphn.c:3:
In function ‘vphn_unpack_associativity’,
inlined from ‘test_one’ at test-vphn.c:371:2,
inlined from ‘test_vphn’ at test-vphn.c:399:9:
test-vphn.c:10:33: error: ‘be_packed’ may be used uninitialized [-Werror=maybe-uninitialized]
10 | #define be16_to_cpup(x) bswap_16(*x)
| ^~~~~~~~
vphn.c:42:27: note: in expansion of macro ‘be16_to_cpup’
42 | u16 new = be16_to_cpup(field++);
| ^~~~~~~~~~~~
In file included from test-vphn.c:19:
vphn.c: In function ‘test_vphn’:
vphn.c:27:16: note: ‘be_packed’ declared here
27 | __be64 be_packed[VPHN_REGISTER_COUNT];
| ^~~~~~~~~
cc1: all warnings being treated as errors
When vphn_unpack_associativity() is called from hcall_vphn() in kernel
the error is not seen while building vphn.c during kernel compilation.
This is because the top level Makefile includes '-fno-strict-aliasing'
flag always.
The issue here is that GCC 15 emits '-Wmaybe-uninitialized' due to type
punning between __be64[] and __b16* when accessing the buffer via
be16_to_cpup(). The underlying object is fully initialized but GCC 15
fails to track the aliasing due to the strict aliasing violation here.
Please refer [1] and [2]. This results in a false positive warning which
is promoted to an error under '-Werror'. This problem is not seen when
the compilation is performed with GCC 13 and 14. An issue [1] has also
been created on GCC bugzilla.
The selftest compiles fine with '-fno-strict-aliasing'. Since this GCC
flag is used to compile vphn.c in kernel too, the same flag should be
used to build vphn tests when compiling vphn.c in the selftest as well.
Fix this by including '-fno-strict-aliasing' during vphn.c compilation
in the selftest. This keeps the build working while limiting the scope
of the suppression to building vphn tests.
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124427
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99768
Fixes: 58dae82843 ("selftests/powerpc: Add test for VPHN")
Reviewed-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: Amit Machhiwal <amachhiw@linux.ibm.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20260313165426.43259-1-amachhiw@linux.ibm.com
Build breaks when executing make with run_tests for sub-folders
under powerpc. This is because, CFLAGS and GIT_VERSION macros are
defined in Makefile of toplevel powerpc folder.
make: Entering directory '/home/maddy/linux/tools/testing/selftests/powerpc/mm'
gcc hugetlb_vs_thp_test.c ../harness.c ../utils.c -o /home/maddy/selftest_output//hugetlb_vs_thp_test
hugetlb_vs_thp_test.c:6:10: fatal error: utils.h: No such file or directory
6 | #include "utils.h"
| ^~~~~~~~~
compilation terminated.
Fix this by adding the flags.mk in each sub-folder Makefile. Also remove
the CFLAGS and GIT_VERSION macros from powerpc/ folder Makefile since
the same is definied in flags.mk
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240229093711.581230-3-maddy@linux.ibm.com
In some powerpc/ sub-folder Makefiles, CFLAGS are defined before lib.mk
include. Clean it up by re-ordering the flags to follow after the mk
include. This is needed to support sub-folders in powerpc/ buildable on
its own.
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240229093711.581230-1-maddy@linux.ibm.com
hcall_vphn() is specific to pseries and will be used in a subsequent
patch. So, move it to a more appropriate place under
arch/powerpc/platforms/pseries. Also merge vphn.h into lppaca.h
and update vphn selftest to use the new files.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit b2d35fa5fc ("selftests: add headers_install to lib.mk")
introduced a requirement that Makefiles more than one level below the
selftests directory need to define top_srcdir, but it didn't update
any of the powerpc Makefiles.
This broke building all the powerpc selftests with eg:
make[1]: Entering directory '/src/linux/tools/testing/selftests/powerpc'
BUILD_TARGET=/src/linux/tools/testing/selftests/powerpc/alignment; mkdir -p $BUILD_TARGET; make OUTPUT=$BUILD_TARGET -k -C alignment all
make[2]: Entering directory '/src/linux/tools/testing/selftests/powerpc/alignment'
../../lib.mk:20: ../../../../scripts/subarch.include: No such file or directory
make[2]: *** No rule to make target '../../../../scripts/subarch.include'.
make[2]: Failed to remake makefile '../../../../scripts/subarch.include'.
Makefile:38: recipe for target 'alignment' failed
Fix it by setting top_srcdir in the affected Makefiles.
Fixes: b2d35fa5fc ("selftests: add headers_install to lib.mk")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently, kselftest use TEST_PROGS, TEST_PROGS_EXTENDED, TEST_FILES to
indicate the test program, extended test program and test files. It is
easy to understand the purpose of these files. But mix of compiled and
uncompiled files lead to duplicated "all" and "clean" targets.
In order to remove the duplicated targets, introduce TEST_GEN_PROGS,
TEST_GEN_PROGS_EXTENDED, TEST_GEN_FILES to indicate the compiled
objects.
Also, the later patch will make use of TEST_GEN_XXX to redirect these
files to output directory indicated by KBUILD_OUTPUT or O.
And add this changes to "Contributing new tests(details)" of
Documentation/kselftest.txt.
Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
These tests were merged in parallel to the install support, update them
now to use it.
This also adds cross compile support for the VPHN test which was missing
it.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The goal is to verify vphn_unpack_associativity() parses VPHN numbers
correctly. We feed it with a variety of input values and compare with
expected results.
PAPR+ does not say much about VPHN parsing: I came up with a list of
tests that check many simple cases and some corner ones. I wouldn't
dare to say the list is exhaustive though.
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
[mpe: Rework harness logic, rename to test-vphn, add -m64]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
