Le 02/09/2024 à 03:20, Jason A. Donenfeld a écrit :
On Sun, Sep 01, 2024 at 08:43:10PM +0200, Christophe Leroy wrote:
How would this fit in the logic where IIUC you just remove '_64' from 'x86_64' to get 'x86'
Huh? That's not what tools/scripts/Makefile.arch does.
Hum ... yes sorry I looked at it too quickly and mixed things up with the other patch.
Nevertheless, if I understand well what tools/scripts/Makefile.arch does on an x86_64 for instance:
uname -m returns x86_64 HOSTARCH = x86 (sed -e s/x86_64/x86) ARCH = x86 SRCARCH = x86
If you build with make ARCH=x86_64, SRCARCH = x86
So I still can't see how you can use that to know if it is a x86_64 or not.
By the use of CONFIG_X86_32, which is also used elsewhere in that samme makefile for something else (so I assume it's wired up in the context where it counts, and if not, that's a bug that affects both spots and should be fixed)..
I looks like it is a left-over from the time vDSO selftests were in Documentation/vDSO and were likely built with kernel config.
CONFIG_X86_32 was brought into tools/testing/selftests/vDSO by commit f9b6b0ef6034 ("selftests: move vDSO tests from Documentation/vDSO") and was meant to pass -lgcc_s when building vdso_standalone_test_x86 for i386, but obviously it doesn't work:
$ make ARCH=i386 V=1 gcc -std=gnu99 -O2 -D_GNU_SOURCE= vdso_test_gettimeofday.c parse_vdso.c -o /home/chleroy/linux-powerpc/tools/testing/selftests/vDSO/vdso_test_gettimeofday gcc -std=gnu99 -O2 -D_GNU_SOURCE= vdso_test_getcpu.c parse_vdso.c -o /home/chleroy/linux-powerpc/tools/testing/selftests/vDSO/vdso_test_getcpu gcc -std=gnu99 -O2 -D_GNU_SOURCE= vdso_test_abi.c parse_vdso.c -o /home/chleroy/linux-powerpc/tools/testing/selftests/vDSO/vdso_test_abi gcc -std=gnu99 -O2 -D_GNU_SOURCE= vdso_test_clock_getres.c -o /home/chleroy/linux-powerpc/tools/testing/selftests/vDSO/vdso_test_clock_getres gcc -std=gnu99 -O2 -D_GNU_SOURCE= -ldl vdso_test_correctness.c -o /home/chleroy/linux-powerpc/tools/testing/selftests/vDSO/vdso_test_correctness
In another place in selftests (tools/testing/selftests/ipc/), they manually add it:
ifeq ($(ARCH),i386) ARCH := x86 CFLAGS := -DCONFIG_X86_32 -D__i386__ endif ifeq ($(ARCH),x86_64) ARCH := x86 CFLAGS := -DCONFIG_X86_64 -D__x86_64__ endif
So I think this is a confirmation that CONFIG_X86_32 doesn't exist in selftests.
Christophe