For testing the functionality of the vDSO, it is necessary to build
userspace programs for multiple different architectures.
It is additional work to acquire matching userspace cross-compilers with
full C libraries and then building root images out of those.
The kernel tree already contains nolibc, a small, header-only C library.
By using it, it is possible to build userspace programs without any
additional dependencies.
For example the kernel.org crosstools or multi-target clang can be used
to build test programs for a multitude of architectures.
While nolibc is very limited, it is enough for many selftests.
With some minor adjustments it is possible to make parse_vdso.c
compatible with nolibc.
As an example, vdso_standalone_test_x86 is now built from the same C
code as the regular vdso_test_gettimeofday, while still being completely
standalone.
This should probably go through the kselftest tree.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
---
Thomas Weißschuh (16):
MAINTAINERS: Add vDSO selftests
elf, uapi: Add definition for STN_UNDEF
elf, uapi: Add definition for DT_GNU_HASH
elf, uapi: Add definitions for VER_FLG_BASE and VER_FLG_WEAK
elf, uapi: Add type ElfXX_Versym
elf, uapi: Add types ElfXX_Verdef and ElfXX_Veraux
tools/include: Add uapi/linux/elf.h
selftests: Add headers target
selftests: vDSO: vdso_standalone_test_x86: Use vdso_init_form_sysinfo_ehdr
selftests: vDSO: parse_vdso: Drop vdso_init_from_auxv()
selftests: vDSO: parse_vdso: Use UAPI headers instead of libc headers
selftests: vDSO: parse_vdso: Test __SIZEOF_LONG__ instead of ULONG_MAX
selftests: vDSO: parse_vdso: Make compatible with nolibc
selftests: vDSO: vdso_test_gettimeofday: Clean up includes
selftests: vDSO: vdso_test_gettimeofday: Make compatible with nolibc
selftests: vDSO: vdso_standalone_test_x86: Switch to nolibc
MAINTAINERS | 1 +
include/uapi/linux/elf.h | 38 ++
tools/include/uapi/linux/elf.h | 524 +++++++++++++++++++++
tools/testing/selftests/lib.mk | 5 +-
tools/testing/selftests/vDSO/Makefile | 11 +-
tools/testing/selftests/vDSO/parse_vdso.c | 21 +-
tools/testing/selftests/vDSO/parse_vdso.h | 1 -
.../selftests/vDSO/vdso_standalone_test_x86.c | 143 +-----
.../selftests/vDSO/vdso_test_gettimeofday.c | 4 +-
9 files changed, 584 insertions(+), 164 deletions(-)
---
base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b
change-id: 20241017-parse_vdso-nolibc-e069baa7ff48
Best regards,
--
Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
