RFR: 8295395: Linux Alpha Zero builds fail after JDK-8292591

[Aleksey Shipilev]

On Mon, 17 Oct 2022 08:05:30 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> Is membarrier on alpha not 517?
> 
> https://github.com/torvalds/linux/blob/master/arch/alpha/kernel/syscalls/syscall.tbl#L448

Ha. The direct test shows it is indeed `517` when cross-compiled with modern GCC:


# sudo chroot /chroots/alpha
# cat test.c 
#include <syscall.h>
#include <stdio.h>

void main() {
  printf("%d\n", __NR_membarrier);
}
# gcc test.c 
# ./a.out 
517


So I was looking at `/usr/alpha-linux-gnu/include/asm-generic/unistd.h`, which defines the arch-specific syscalls:


#define __NR_membarrier 283
__SYSCALL(__NR_membarrier, sys_membarrier)


...but there is also a definition in `/usr/alpha-linux-gnu/include/asm/unistd_32.h`:


440:#define __NR_membarrier 517


I guess we should trust `517` here.

-------------

PR: https://git.openjdk.org/jdk/pull/10721