selftests/seccomp: add Alpha support to seccomp_bpf

Enable the seccomp BPF selftests on Alpha with a fallback seccomp syscall
number and architecture-specific syscall register accessors.

Use the NT_PRSTATUS register layout rather than struct pt_regs. The
register set contains r0-r30 followed by pc and unique. Read and update
the syscall number in r1, and set both r0 and the r19/a3 error flag when
synthesizing syscall results.

At syscall entry, r19 still contains the fourth syscall argument, so
callers setting a synthetic return value must also set the syscall
number to -1 to skip execution.

Reviewed-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>
Link: https://lore.kernel.org/r/20261010134214.974565-1-linmag7@gmail.com
Signed-off-by: Magnus Lindholm <linmag7@gmail.com>

0 files changed, 0 insertions, 0 deletions