[PATCH 0/5] selftests: target selection fixes for cross and LLVM builds

[PATCH 0/5] selftests: target selection fixes for cross and LLVM builds

[Sasha Levin]

A few suites select their tests from the build host instead of the
target, or depend on the host C library in ways that break cross
builds. This series fixes the ones found while building the selftests
for several architectures:

 - prctl and the Intel thermal suites build nothing when CROSS_COMPILE
   is set, even for x86, and prctl restricts two generic tests to x86.

 - set-anon-vma-name-test fails instead of skipping on kernels built
   without CONFIG_ANON_VMA_NAME.

 - kexec only recognizes the ppc64le spelling of PowerPC and decides
   about the x86-64 jump test from the build host.

 - size links a custom _start against the static C library, which
   fails on ARM with clang and on LoongArch; it now uses nolibc.

The patches are independent of each other.

Sasha Levin (5):
  selftests/prctl: build generated tests for the target architecture
  selftests/prctl: skip the anonymous VMA naming test when unsupported
  selftests/thermal: allow cross builds of the Intel tests
  selftests/kexec: select tests using the target compiler
  selftests/size: use nolibc startup and syscall wrappers

 tools/testing/selftests/kexec/Makefile        | 26 ++++++++-------
 tools/testing/selftests/prctl/Makefile        | 18 +++++-----
 .../selftests/prctl/set-anon-vma-name-test.c  |  3 ++
 tools/testing/selftests/size/Makefile         |  9 ++++-
 tools/testing/selftests/size/get_size.c       | 33 +++++--------------
 .../thermal/intel/power_floor/Makefile        | 12 +++----
 .../thermal/intel/workload_hint/Makefile      | 12 +++----
 7 files changed, 52 insertions(+), 61 deletions(-)


base-commit: 4eb2586bd40db27d77cc5b724ca9386ed0c71d53
-- 
2.53.0

[PATCH 4/5] selftests/kexec: select tests using the target compiler

[Sasha Levin]

The kexec Makefile recognizes PowerPC only through the ppc64le spelling
of ARCH, so the canonical ARCH=powerpc used for cross builds omits the
tests. The x86 jump test is selected with IS_64_BIT from
scripts/Makefile.arch, which describes the build host rather than the
compiler being used. On other architectures the Makefile includes no
lib.mk rules at all, so installation and runlist generation fail with
missing targets.

Select x86 and PowerPC from the target ARCH when it is given and from
the host's SUBARCH otherwise, without assigning ARCH, so that lib.mk
keeps choosing the compiler's native clang target. Ask the selected
compiler, including USERCFLAGS, whether it targets a 64-bit x86 ABI
and whether it targets little-endian 64-bit PowerPC. lib.mk expands the
generated program list before it appends USERCFLAGS to CFLAGS, so the
flags are passed explicitly to keep both probes consistent. If the
compiler cannot be run, select the jump test so that the build fails
instead of silently dropping it. Include lib.mk unconditionally so that
unsupported targets build, install and emit an empty runlist.

Fixes: 65e38e32a959 ("selftests/kexec: Enable secureboot tests for PowerPC")
Fixes: 7615b94b6371 ("selftests/kexec: Add x86_64 selftest for kexec-jump and exception handling")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/testing/selftests/kexec/Makefile | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/kexec/Makefile b/tools/testing/selftests/kexec/Makefile
index 874cfdd3b75b3..97d5dd10208a1 100644
--- a/tools/testing/selftests/kexec/Makefile
+++ b/tools/testing/selftests/kexec/Makefile
@@ -1,20 +1,22 @@
 # SPDX-License-Identifier: GPL-2.0-only
 # Makefile for kexec tests
 
-ARCH ?= $(shell uname -m 2>/dev/null || echo not)
-ARCH_PROCESSED := $(shell echo $(ARCH) | sed -e s/i.86/x86/ -e s/x86_64/x86/)
+top_srcdir = ../../../..
+include $(top_srcdir)/scripts/subarch.include
+ARCH_PROCESSED := $(shell echo $(or $(ARCH),$(SUBARCH)) | sed -e s/i.86/x86/ -e s/x86_64/x86/)
 
-ifeq ($(ARCH_PROCESSED),$(filter $(ARCH_PROCESSED),x86 ppc64le))
-TEST_PROGS := test_kexec_load.sh test_kexec_file_load.sh
-TEST_FILES := kexec_common_lib.sh
+PROBE_CC = $(filter-out -fuse-ld=%,$(CC)) $(CFLAGS) $(USERCFLAGS) -E -P -x c -
+CC_IS_64BIT = $(shell echo __SIZEOF_LONG__ | $(PROBE_CC) || echo 8)
+PPC64LE = $(shell printf '\043if defined(__powerpc64__) && __BYTE_ORDER__ == \
+	__ORDER_LITTLE_ENDIAN__\n1\n\043endif\n' | $(PROBE_CC))
 
-include ../../../scripts/Makefile.arch
-
-ifeq ($(IS_64_BIT)$(ARCH_PROCESSED),1x86)
-TEST_PROGS += test_kexec_jump.sh
-TEST_GEN_PROGS := test_kexec_jump
+ifeq ($(ARCH_PROCESSED),x86)
+TEST_PROGS = test_kexec_load.sh test_kexec_file_load.sh \
+	$(if $(filter 8,$(CC_IS_64BIT)),test_kexec_jump.sh)
+TEST_GEN_PROGS = $(if $(filter 8,$(CC_IS_64BIT)),test_kexec_jump)
+else ifneq (,$(filter powerpc ppc64le,$(ARCH_PROCESSED)))
+TEST_PROGS = $(if $(filter 1,$(PPC64LE)),test_kexec_load.sh test_kexec_file_load.sh)
 endif
+TEST_FILES = $(if $(TEST_PROGS),kexec_common_lib.sh)
 
 include ../lib.mk
-
-endif
-- 
2.53.0

Re: [PATCH 4/5] selftests/kexec: select tests using the target compiler

[sashiko-bot]

> The kexec Makefile recognizes PowerPC only through the ppc64le spelling
> of ARCH, so the canonical ARCH=powerpc used for cross builds omits the
> tests. The x86 jump test is selected with IS_64_BIT from
> scripts/Makefile.arch, which describes the build host rather than the
> compiler being used. On other architectures the Makefile includes no
> lib.mk rules at all, so installation and runlist generation fail with
> missing targets.
> 
> Select x86 and PowerPC from the target ARCH when it is given and from
> the host's SUBARCH otherwise, without assigning ARCH, so that lib.mk
> keeps choosing the compiler's native clang target. Ask the selected
> compiler, including USERCFLAGS, whether it targets a 64-bit x86 ABI
> and whether it targets little-endian 64-bit PowerPC. lib.mk expands the
> generated program list before it appends USERCFLAGS to CFLAGS, so the
> flags are passed explicitly to keep both probes consistent. If the
> compiler cannot be run, select the jump test so that the build fails
> instead of silently dropping it. Include lib.mk unconditionally so that
> unsupported targets build, install and emit an empty runlist.
> 
> Fixes: 65e38e32a959 ("selftests/kexec: Enable secureboot tests for PowerPC")
> Fixes: 7615b94b6371 ("selftests/kexec: Add x86_64 selftest for kexec-jump and exception handling")
> Signed-off-by: Sasha Levin <sashal@kernel.org>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261014200127.1363472-1-sashal@kernel.org?part=4