Enable S390 booting

[nathanchance]

This is blocked on getting a newer copy of QEMU that has https://lore.kernel.org/qemu-devel/20210111163845.18148-1-david@redhat.com/

We could potentially start distributing a qemu-system-s390 binary in the boot-utils repo.

[nathanchance]

So I have some prototyping done on this already:

nathanchance/boot-utils@4733c93

https://github.com/nathanchance/continuous-integration2/commits/1b7c902e5a519d66d00f6a96eb855fae9d803767

I am not sure of placing the qemu binaries in boot-utils itself though. I feel that creating a standalone repo like qemu-binaries is more flexible, in case we need to add any more over time (this is not the first time we have needed an updated version of QEMU). They should be built in an Ubuntu 20.04 environment/container to ensure a consistent environment. I will explore this tomorrow.

Doing a PPA might be even better but I would prefer not to go down that path unless absolutely necessary, working with Debian packaging is just not fun.

[nathanchance]

Part 1: ClangBuiltLinux/qemu-binaries#1

Part 2: ClangBuiltLinux/boot-utils#32

Part 3: This repo, which will involve updating the boot-utils submodule and adding --use-cbl-qemu in check_logs.py when ARCH is s390:

diff --git a/check_logs.py b/check_logs.py
index 97a8ac1..d21eaac 100755
--- a/check_logs.py
+++ b/check_logs.py
@@ -69,10 +69,13 @@ def cwd():
 def run_boot():
     cbl_arch = get_cbl_name()
     kernel_image = cwd() + "/" + get_image_name()
+    boot_qemu = [
+        "./boot-utils/boot-qemu.sh", "-a", cbl_arch, "-k", kernel_image
+    ]
+    if cbl_arch == "s390":
+        boot_qemu += ["--use-cbl-qemu"]
     try:
-        subprocess.run(
-            ["./boot-utils/boot-qemu.sh", "-a", cbl_arch, "-k", kernel_image],
-            check=True)
+        subprocess.run(boot_qemu, check=True)
     except subprocess.CalledProcessError as e:
         if e.returncode == 124:
             print_red("Image failed to boot")
diff --git a/generator.yml b/generator.yml
index 7c79273..bf3a541 100644
--- a/generator.yml
+++ b/generator.yml
@@ -103,8 +103,7 @@ builds:
   # riscv: Boot disabled (https://github.com/ClangBuiltLinux/continuous-integration2/issues/27)
   # - {<< : *riscv,      << : *mainline,         << : *riscv_llvm_full, boot: false, llvm_version: *llvm_tot}
   # s390: Build disabled (https://github.com/ClangBuiltLinux/continuous-integration2/issues/34)
-  # s390: Boot disabled (https://github.com/ClangBuiltLinux/continuous-integration2/issues/42)
-  # - {<< : *s390,       << : *mainline,         << : *clang,           boot: false, llvm_version: *llvm_tot}
+  # - {<< : *s390,       << : *mainline,         << : *clang,           boot: true,  llvm_version: *llvm_tot}
   - {<< : *x86_64,     << : *mainline,         << : *llvm_full,       boot: true,  llvm_version: *llvm_tot}
   ##########
   #  Next  #
@@ -127,8 +126,7 @@ builds:
   # riscv: Boot disabled (https://github.com/ClangBuiltLinux/continuous-integration2/issues/27)
   # - {<< : *riscv,      << : *next,             << : *riscv_llvm_full, boot: false, llvm_version: *llvm_tot}
   # s390: Build disabled (https://github.com/ClangBuiltLinux/continuous-integration2/issues/34)
-  # s390: Boot disabled (https://github.com/ClangBuiltLinux/continuous-integration2/issues/42)
-  # - {<< : *s390,       << : *next,             << : *clang,           boot: false, llvm_version: *llvm_tot}
+  # - {<< : *s390,       << : *next,             << : *clang,           boot: true,  llvm_version: *llvm_tot}
   - {<< : *x86_64,     << : *next,             << : *llvm_full,       boot: true,  llvm_version: *llvm_tot}
   ############
   #  5.10.y  #
@@ -151,8 +149,7 @@ builds:
   # riscv: Boot disabled (https://github.com/ClangBuiltLinux/continuous-integration2/issues/27)
   # - {<< : *riscv,      << : *stable-5_10,      << : *riscv_llvm_full, boot: false, llvm_version: *llvm_tot}
   # s390: Build disabled (https://github.com/ClangBuiltLinux/continuous-integration2/issues/34)
-  # s390: Boot disabled (https://github.com/ClangBuiltLinux/continuous-integration2/issues/42)
-  # - {<< : *s390,       << : *stable-5_10,      << : *clang,           boot: false, llvm_version: *llvm_tot}
+  # - {<< : *s390,       << : *stable-5_10,      << : *clang,           boot: boot,  llvm_version: *llvm_tot}
   - {<< : *x86_64,     << : *stable-5_10,      << : *llvm_full,       boot: true,  llvm_version: *llvm_tot}
   ###########
   #  5.4.y  #
@@ -229,6 +226,5 @@ builds:
   # - {<< : *ppc32,      << : *mainline,         << : *llvm,            boot: false, llvm_version: *llvm_latest}
   # - {<< : *ppc64,      << : *mainline,         << : *ppc64_llvm,      boot: false, llvm_version: *llvm_latest}
   - {<< : *ppc64le,    << : *mainline,         << : *llvm,            boot: false, llvm_version: *llvm_latest}
-  # s390: Boot disabled (https://github.com/ClangBuiltLinux/continuous-integration2/issues/42)
-  - {<< : *s390,       << : *mainline,         << : *clang,           boot: false, llvm_version: *llvm_latest}
+  - {<< : *s390,       << : *mainline,         << : *clang,           boot: true,  llvm_version: *llvm_latest}
   - {<< : *x86_64,     << : *mainline,         << : *llvm_full,       boot: true,  llvm_version: *llvm_latest}