linux-dev/tools/testing/selftests/nolibc, branch master

selftests/nolibc: Avoid generated files being committed

2022-08-31T12:17:45Z

After running the nolibc tests, the "git status" is not clean because the generated files are not ignored. Create a `.gitignore` inside the selftests/nolibc directory to ignore them. Cc: Ammar Faizi Cc: Fernanda Ma'rouf Signed-off-by: Fernanda Ma'rouf Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney

selftests/nolibc: add a "help" target

2022-08-31T12:17:45Z

It presents the supported targets, and becomes the default target to save the user from having to read the makefile. The "all" target was placed after it and now points to "run" to do everything since it's no longer the default one. Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney

selftests/nolibc: "sysroot" target installs a local copy of the sysroot

2022-08-31T12:17:45Z

It's not convenient to rely on a sysroot built in another directory, especially when running cross-compilation tests, where one has to switch back and forth between directories. Let's make it possible to install the sysroot directly in the test directory. It's not big and even benefits from being copied by arch so that it's easier to switch between archs if needed. The new "sysroot" target does this, it just calls "headers_standalone" from nolibc to install the sysroot right here. Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney

selftests/nolibc: add a "run" target to start the kernel in QEMU

2022-08-31T12:17:45Z

The "run" target will build the kernel and start it in QEMU. The "rerun" target will not have the kernel dependency and will just try to start QEMU. The QEMU architecture used to start the kernel is derived from the configured ARCH. This might need to be improved for archs which include different variants under the same name (mips vs mipsel, +/-64, riscv32 vs riscv64). This could be tested for i386, x86, arm, arm64, mips and riscv (the later two reporting issues on some tests). It is possible to pass a test specification for nolibc-test in the TEST variable, which will be passed as-is as NOLIBC_TEST. On success, the number of successful tests is printed. On failure, failed lines are individually printed. Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney

selftests/nolibc: add a "defconfig" target

2022-08-31T12:17:45Z

While most archs will work fine with "make defconfig", not all will do, and it's not always easy to remember the most suitable choice to use for a specific architecture. This adds a "defconfig" target to the Makefile so that one may easily run "make -C ... defconfig" and make sure to clean and rebuild a fresh config. This is *not* used by default because we want to preserve the user's config by default. Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney

selftests/nolibc: add a "kernel" target to build the kernel with the initramfs

2022-08-31T12:17:45Z

The "kernel" target rebuilds the kernel with the current config for the selected arch, with an initramfs containing the nolibc-test utility. Since image names depend on the architecture, the currently supported ones are referenced and resolved based on the architecture. Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney

selftests/nolibc: support glibc as well

2022-08-31T12:17:44Z

Adding support for glibc can be useful to distinguish between bugs in nolibc and bugs in the kernel when a syscall reports an unusual value. It's not that much work and should not affect the long term maintainability of the tests. The necessary changes can essentially be summed up like this: - set _GNU_SOURCE a the top to access some definitions - many includes added when we know we don't come from nolibc (missing the stdio include guard) - disable gettid() which is not exposed by glibc - disable gettimeofday's support of bad pointers since these crash in glibc - add a simple itoa() for errorname(); strerror() is too verbose (no way to get short messages). strerrorname_np() was added in modern glibc (2.32) to do exactly this but that 's too recent to be usable as the default fallback. - use the standard ioperm() definition. May be we need to implement ioperm() in nolibc if that's useful. Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney

selftests/nolibc: condition some tests on /proc existence

2022-08-31T12:17:44Z

If /proc is not available (program run inside a chroot or without sufficient permissions), it's better to disable the associated tests. Some will be preserved like the ones which check for a failure to create some entries there since they're still supposed to fail. Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney

selftests/nolibc: recreate and populate /dev and /proc if missing

2022-08-31T12:17:44Z

Most of the time the program will be run alone in an initramfs. There is no value in requiring the user to populate /dev and /proc for such tests, we can do it ourselves, and it participates to the tests at the same time. What's done here is that when called as init (getpid()==1) we check if /dev exists or create it, if /dev/console and /dev/null exists, otherwise we try to mount a devtmpfs there, and if it fails we fall back to mknod. The console is reopened if stdout was closed. Finally /proc is created and mounted if /proc/self cannot be found. This is sufficient for most tests. Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney

selftests/nolibc: on x86, support exiting with isa-debug-exit

2022-08-31T12:17:44Z

QEMU, when started with "-device isa-debug-exit -no-reboot" will exit with status code 2N+1 when N is written to 0x501. This is particularly convenient for automated tests but this is not portable. As such we only enable this on x86_64 when pid==1. In addition, this requires an ioperm() call but in order not to have to define arch-specific syscalls we just perform the syscall by hand there. Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney