RFE: add Alpha support

[glaubitz]

This adds architecture support for Alpha, the other architecture besides SPARC which is unsupported yet.

A patch to add support for SECCOMP_FILTER was just posted to LKML.

This PR is missing the update to src/syscalls.csv since I have no clue how that works now. See this issue.

CC @linmag7 who is working on the kernel part.

[coveralls]

coverage: 88.986% (-0.04%) from 89.024%
when pulling a494011 on glaubitz:alpha-support
into 4b0bf50 on seccomp:main.

[linmag7]

Hi all,

I've been running the libseccomp test suit (make check) on my Alpha UP2000+ with a kernel patched for libseccomp support, here are some results:

Regression Test Summary
tests run: 3891
tests skipped: 126
tests passed: 3715
tests failed: 176
tests errored: 149

So it mostly works I'd say! great work with libseccomp!. Below are some of the tests that fail:

Test 33-sim-socket_syscalls_be%%001-00001 result: ERROR 33-sim-socket_syscalls_be rc=14
test arch: s390
Test 33-sim-socket_syscalls_be%%002-00001 result: ERROR 33-sim-socket_syscalls_be rc=14
test arch: s390

Test 34-sim-basic_denylist%%003-00001 result: FAILURE bpf_sim resulted in ALLOW
Test 34-sim-basic_denylist%%003-00002 result: FAILURE bpf_sim resulted in ALLOW

Test 43-sim-a2_order%%031-00001 result: FAILURE bpf_sim resulted in KILL
Test 43-sim-a2_order%%032-00001 result: FAILURE bpf_sim resulted in KILL

Test 62-sim-arch_transactions%%001-00001 result: FAILURE bpf_sim resulted in ALLOW
Test 62-sim-arch_transactions%%002-00001 result: FAILURE bpf_sim resulted in ALLOW

Test 53-sim-binary_tree%%001-00001 result: ERROR 53-sim-binary_tree rc=14
test arch: x86_64

I haven't yet looked into the details as to why tests fail, seems like some of them just assumes the
wrong arch?

[pcmoore]

Without looking at the patch, I just want to remind everyone that we generally don't merge new architecture support until we have a released upstream kernel with seccomp support for that architecture.

[pcmoore]

Looking at Linus' tree, it doesn't appear that the seccomp support patch for Alpha has landed.

[glaubitz]

Looking at Linus' tree, it doesn't appear that the seccomp support patch for Alpha has landed.

It's part of Magnus Lindholm's tree in the for-next branch and will be submitted once the merge window opens again.

[pcmoore]

Great, we'll look forward to that. Hopefully that will give folks enough time to sort out the test failures.

On a personal note, my first job out of college was working on Tru64 UNIX for the Alpha, merging Alpha support into libseccomp would make me very happy :)

[glaubitz]

Support for SECCOMP and SECCOMP_FILTER was just merged into Linus' tree.

See: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/alpha?id=55b22075f7840ef48254886758976531fe146609

[glaubitz]

@pcmoore Ping. All bits and pieces are now in the upstream kernel. ;-)

[drakenclimber]

@glaubitz . I applied your Alpha patch on top of the latest proposed syscall table from Pull Request #487. I then updated syscalls.csv with an Alpha column and populated it via arch-syscall-validate. See this commit - drakenclimber@45211d9. Note that some tests are still failing, so we still have some work to do.

[drakenclimber]

Super duper nitpick - in the rest of this patchset, alpha comes after aarch64, but in this case statement, it's after x32. For consistency, it should be moved down below aarch64.