Messages in this thread | | | Date | Tue, 19 Jan 2021 17:02:38 +0000 | From | Mark Rutland <> | Subject | Re: rcutorture initrd/nolibc build on ARMv8? |
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Hi Willy,
On Tue, Jan 19, 2021 at 05:19:01PM +0100, Willy Tarreau wrote: > On Tue, Jan 19, 2021 at 07:31:47AM -0800, Paul E. McKenney wrote: > > Some people are having trouble running rcutorture on ARMv8. They > > get things like this from the nolibc build of initrd: > > > > https://paste.debian.net/1181762/ > > > > The nolibc.h file says this: > > > > /* Some archs (at least aarch64) don't expose the regular syscalls anymore by > > * default, either because they have an "_at" replacement, or because there are > > * more modern alternatives. For now we'd rather still use them. > > */ > > > > Are these build failures expected behavior on ARMv8? > > No, I don't think so. I'm regularly building my own init using this, > and it works on various platforms including aarch64, while it makes > use of a number of such syscalls. > > From what I'm seeing, this seems to happen each time in such a construct: > > #if defined(__NR_new_name) > use __NR_new_name > #else > use __NR_old_name > #endif > > with the error appearing on old_name. So I guess that we're rather facing a > case where a number of such __NR_* entries are not defined because presumably > one include file might be missing (probably from a recent change of headers > dependency). > > I can't spot from the report above the original C file that was attempted > to be built, it makes me think we tried to compile directly the .h file.
That was the inline snippet in tools/testing/selftests/rcutorture/bin/mkinitrd.sh:
| #ifndef NOLIBC | #include <unistd.h> | #include <sys/time.h> | #endif | | volatile unsigned long delaycount; | | int main(int argc, int argv[]) | { | int i; | struct timeval tv; | struct timeval tvb; | | for (;;) { | sleep(1); | /* Need some userspace time. */ | if (gettimeofday(&tvb, NULL)) | continue; | do { | for (i = 0; i < 1000 * 100; i++) | delaycount = i * i; | if (gettimeofday(&tv, NULL)) | break; | tv.tv_sec -= tvb.tv_sec; | if (tv.tv_sec > 1) | break; | tv.tv_usec += tv.tv_sec * 1000 * 1000; | tv.tv_usec -= tvb.tv_usec; | } while (tv.tv_usec < 1000); | } | return 0; | }
... which gets written to a file called init.c, and then built with:
| ${CROSS_COMPILE}gcc -fno-asynchronous-unwind-tables -fno-ident \ | -nostdlib -include ../../../../include/nolibc/nolibc.h \ | -lgcc -s -static -Os -o init init.c
I was building natively on an arm64 box:
| ./tools/testing/selftests/rcutorture/bin/kvm.sh \ | --cpus 250 --trust-make --configs "TREE03" \ | --kmake-arg "CROSS_COMPILE=aarch64-linux-gnu- ARCH=arm64"
> Having it run through sh -x would help me try to locate the root cause or > possibly even attempt to reproduce it.
I ran with sh -x, but it didn't log the compiler invocation; hopefully the above is sufficient?
Thanks, Mark.
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