Le 03/02/2025 à 10:05, Thomas Weißschuh a écrit :
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.
Not sure what are the expectations with this series.
I gave it a try with vdso_test_gettimeofday and get the following:
$ powerpc64-linux-gcc -nostdlib -nostdinc -ffreestanding -fno-asynchronous-unwind-tables -fno-stack-protector -include /home/chleroy/linux-powerpc/tools/testing/selftests/../../../tools/include/nolibc/nolibc.h -I/home/chleroy/linux-powerpc/tools/testing/selftests/../../../tools/include/nolibc/ -isystem /home/chleroy/linux-powerpc/tools/testing/selftests/../../../usr/include -std=gnu99 -O2 -D_GNU_SOURCE= -isystem /home/chleroy/linux-powerpc/tools/testing/selftests/../../../tools/include/uapi vdso_test_gettimeofday.c parse_vdso.c -o /home/chleroy/linux-powerpc/tools/testing/selftests/vDSO/vdso_test_gettimeofday
make: Entering directory '/home/chleroy/linux-powerpc/tools/testing/selftests/vDSO' powerpc64-linux-gcc -nostdlib -nostdinc -ffreestanding -fno-asynchronous-unwind-tables -fno-stack-protector -include /home/chleroy/linux-powerpc/tools/testing/selftests/../../../tools/include/nolibc/nolibc.h -I/home/chleroy/linux-powerpc/tools/testing/selftests/../../../tools/include/nolibc/ -isystem /home/chleroy/linux-powerpc/tools/testing/selftests/../../../usr/include -std=gnu99 -O2 -D_GNU_SOURCE= -isystem /home/chleroy/linux-powerpc/tools/testing/selftests/../../../tools/include/uapi vdso_test_gettimeofday.c parse_vdso.c -o /home/chleroy/linux-powerpc/tools/testing/selftests/vDSO/vdso_test_gettimeofday parse_vdso.c:38:34: error: unknown type name 'Elf64_Versym' 38 | #define ELF_BITS_XFORM2(bits, x) Elf##bits##_##x | ^~~ parse_vdso.c:39:33: note: in expansion of macro 'ELF_BITS_XFORM2' 39 | #define ELF_BITS_XFORM(bits, x) ELF_BITS_XFORM2(bits, x) | ^~~~~~~~~~~~~~~ parse_vdso.c:40:16: note: in expansion of macro 'ELF_BITS_XFORM' 40 | #define ELF(x) ELF_BITS_XFORM(ELF_BITS, x) | ^~~~~~~~~~~~~~ parse_vdso.c:63:9: note: in expansion of macro 'ELF' 63 | ELF(Versym) *versym; | ^~~ parse_vdso.c:38:34: error: unknown type name 'Elf64_Verdef' 38 | #define ELF_BITS_XFORM2(bits, x) Elf##bits##_##x | ^~~ parse_vdso.c:39:33: note: in expansion of macro 'ELF_BITS_XFORM2' 39 | #define ELF_BITS_XFORM(bits, x) ELF_BITS_XFORM2(bits, x) | ^~~~~~~~~~~~~~~ parse_vdso.c:40:16: note: in expansion of macro 'ELF_BITS_XFORM' 40 | #define ELF(x) ELF_BITS_XFORM(ELF_BITS, x) | ^~~~~~~~~~~~~~ parse_vdso.c:64:9: note: in expansion of macro 'ELF' 64 | ELF(Verdef) *verdef; | ^~~ parse_vdso.c: In function 'vdso_init_from_sysinfo_ehdr': parse_vdso.c:38:34: error: 'Elf64_Versym' undeclared (first use in this function); did you mean 'Elf64_Sym'? 38 | #define ELF_BITS_XFORM2(bits, x) Elf##bits##_##x | ^~~ parse_vdso.c:39:33: note: in expansion of macro 'ELF_BITS_XFORM2' 39 | #define ELF_BITS_XFORM(bits, x) ELF_BITS_XFORM2(bits, x) | ^~~~~~~~~~~~~~~ parse_vdso.c:40:16: note: in expansion of macro 'ELF_BITS_XFORM' 40 | #define ELF(x) ELF_BITS_XFORM(ELF_BITS, x) | ^~~~~~~~~~~~~~ parse_vdso.c:150:45: note: in expansion of macro 'ELF' 150 | vdso_info.versym = (ELF(Versym) *) | ^~~ parse_vdso.c:38:34: note: each undeclared identifier is reported only once for each function it appears in 38 | #define ELF_BITS_XFORM2(bits, x) Elf##bits##_##x | ^~~ parse_vdso.c:39:33: note: in expansion of macro 'ELF_BITS_XFORM2' 39 | #define ELF_BITS_XFORM(bits, x) ELF_BITS_XFORM2(bits, x) | ^~~~~~~~~~~~~~~ parse_vdso.c:40:16: note: in expansion of macro 'ELF_BITS_XFORM' 40 | #define ELF(x) ELF_BITS_XFORM(ELF_BITS, x) | ^~~~~~~~~~~~~~ parse_vdso.c:150:45: note: in expansion of macro 'ELF' 150 | vdso_info.versym = (ELF(Versym) *) | ^~~ parse_vdso.c:150:58: error: expected expression before ')' token 150 | vdso_info.versym = (ELF(Versym) *) | ^ parse_vdso.c:38:34: error: 'Elf64_Verdef' undeclared (first use in this function); did you mean 'Elf64_Word'? 38 | #define ELF_BITS_XFORM2(bits, x) Elf##bits##_##x | ^~~ parse_vdso.c:39:33: note: in expansion of macro 'ELF_BITS_XFORM2' 39 | #define ELF_BITS_XFORM(bits, x) ELF_BITS_XFORM2(bits, x) | ^~~~~~~~~~~~~~~ parse_vdso.c:40:16: note: in expansion of macro 'ELF_BITS_XFORM' 40 | #define ELF(x) ELF_BITS_XFORM(ELF_BITS, x) | ^~~~~~~~~~~~~~ parse_vdso.c:155:45: note: in expansion of macro 'ELF' 155 | vdso_info.verdef = (ELF(Verdef) *) | ^~~ parse_vdso.c:155:58: error: expected expression before ')' token 155 | vdso_info.verdef = (ELF(Verdef) *) | ^ parse_vdso.c: At top level: parse_vdso.c:38:34: error: unknown type name 'Elf64_Versym'; did you mean 'Elf64_Sym'? 38 | #define ELF_BITS_XFORM2(bits, x) Elf##bits##_##x | ^~~ parse_vdso.c:39:33: note: in expansion of macro 'ELF_BITS_XFORM2' 39 | #define ELF_BITS_XFORM(bits, x) ELF_BITS_XFORM2(bits, x) | ^~~~~~~~~~~~~~~ parse_vdso.c:40:16: note: in expansion of macro 'ELF_BITS_XFORM' 40 | #define ELF(x) ELF_BITS_XFORM(ELF_BITS, x) | ^~~~~~~~~~~~~~ parse_vdso.c:177:32: note: in expansion of macro 'ELF' 177 | static bool vdso_match_version(ELF(Versym) ver, | ^~~ parse_vdso.c: In function 'vdso_sym': parse_vdso.c:224:25: error: 'STN_UNDEF' undeclared (first use in this function); did you mean 'SHN_UNDEF'? 224 | for (; chain != STN_UNDEF; chain = vdso_info.chain[chain]) { | ^~~~~~~~~ | SHN_UNDEF parse_vdso.c:240:25: warning: implicit declaration of function 'vdso_match_version' [-Wimplicit-function-declaration] 240 | && !vdso_match_version(vdso_info.versym[chain], | ^~~~~~~~~~~~~~~~~~ make: *** [../lib.mk:222: /home/chleroy/linux-powerpc/tools/testing/selftests/vDSO/vdso_test_gettimeofday] Error 1 make: Leaving directory '/home/chleroy/linux-powerpc/tools/testing/selftests/vDSO'
Christophe
Signed-off-by: Thomas Weißschuh thomas.weissschuh@linutronix.de
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,