Merge tag 'nolibc.2022.09.30a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull nolibc updates from Paul McKenney:
 "Most notably greatly improved testing. These tests are located in
  tools/testing/selftests/nolibc. The output of "make help" is as
  follows:

    Supported targets under selftests/nolibc:
      all          call the "run" target below
      help         this help
      sysroot      create the nolibc sysroot here (uses $ARCH)
      nolibc-test  build the executable (uses $CC and $CROSS_COMPILE)
      initramfs    prepare the initramfs with nolibc-test
      defconfig    create a fresh new default config (uses $ARCH)
      kernel       (re)build the kernel with the initramfs (uses $ARCH)
      run          runs the kernel in QEMU after building it (uses $ARCH, $TEST)
      rerun        runs a previously prebuilt kernel in QEMU (uses $ARCH, $TEST)
      clean        clean the sysroot, initramfs, build and output files

    The output file is "run.out". Test ranges may be passed using $TEST.

    Currently using the following variables:
      ARCH          = x86
      CROSS_COMPILE =
      CC            = gcc
      OUTPUT        = /home/git/linux-rcu/tools/testing/selftests/nolibc/
      TEST          =
      QEMU_ARCH     = x86_64 [determined from $ARCH]
      IMAGE_NAME    = bzImage [determined from $ARCH]

  The output of a successful x86 "make run" is currently as follows,
  with kernel build output omitted:

    $ make run
    71 test(s) passed."

* tag 'nolibc.2022.09.30a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
  selftests/nolibc: Avoid generated files being committed
  selftests/nolibc: add a "help" target
  selftests/nolibc: "sysroot" target installs a local copy of the sysroot
  selftests/nolibc: add a "run" target to start the kernel in QEMU
  selftests/nolibc: add a "defconfig" target
  selftests/nolibc: add a "kernel" target to build the kernel with the initramfs
  selftests/nolibc: support glibc as well
  selftests/nolibc: condition some tests on /proc existence
  selftests/nolibc: recreate and populate /dev and /proc if missing
  selftests/nolibc: on x86, support exiting with isa-debug-exit
  selftests/nolibc: exit with poweroff on success when getpid() == 1
  selftests/nolibc: add a few tests for some libc functions
  selftests/nolibc: implement a few tests for various syscalls
  selftests/nolibc: support a test definition format
  selftests/nolibc: add basic infrastructure to ease creation of nolibc tests
  tools/nolibc: make sys_mmap() automatically use the right __NR_mmap definition
  tools/nolibc: fix build warning in sys_mmap() when my_syscall6 is not defined
  tools/nolibc: make argc 32-bit in riscv startup code

MAINTAINERS

@@ -14449,6 +14449,7 @@ M:	Willy Tarreau <w@1wt.eu>
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/wtarreau/nolibc.git
 F:	tools/include/nolibc/
+F:	tools/testing/selftests/nolibc/
 
 NSDEPS
 M:	Matthias Maennich <maennich@google.com>

tools/include/nolibc/arch-riscv.h

@@ -190,7 +190,7 @@ __asm__ (".section .text\n"
     ".option norelax\n"
     "lla   gp, __global_pointer$\n"
     ".option pop\n"
-    "ld    a0, 0(sp)\n"          // argc (a0) was in the stack
+    "lw    a0, 0(sp)\n"          // argc (a0) was in the stack
     "add   a1, sp, "SZREG"\n"    // argv (a1) = sp
     "slli  a2, a0, "PTRLOG"\n"   // envp (a2) = SZREG*argc ...
     "add   a2, a2, "SZREG"\n"    //             + SZREG (skip null)

tools/include/nolibc/sys.h

@@ -692,12 +692,12 @@ void *sys_mmap(void *addr, size_t length, int prot, int flags, int fd,
 {
 #ifndef my_syscall6
 	/* Function not implemented. */
-	return -ENOSYS;
+	return (void *)-ENOSYS;
 #else
 
 	int n;
 
-#if defined(__i386__)
+#if defined(__NR_mmap2)
 	n = __NR_mmap2;
 	offset >>= 12;
 #else

tools/testing/selftests/nolibc/.gitignore

+/initramfs/
+/nolibc-test
+/run.out
+/sysroot/

tools/testing/selftests/nolibc/Makefile

+# SPDX-License-Identifier: GPL-2.0
+# Makefile for nolibc tests
+include ../../../scripts/Makefile.include
+
+# we're in ".../tools/testing/selftests/nolibc"
+ifeq ($(srctree),)
+srctree := $(patsubst %/tools/testing/selftests/,%,$(dir $(CURDIR)))
+endif
+
+ifeq ($(ARCH),)
+include $(srctree)/scripts/subarch.include
+ARCH = $(SUBARCH)
+endif
+
+# kernel image names by architecture
+IMAGE_i386    = arch/x86/boot/bzImage
+IMAGE_x86     = arch/x86/boot/bzImage
+IMAGE_arm64   = arch/arm64/boot/Image
+IMAGE_arm     = arch/arm/boot/zImage
+IMAGE_mips    = vmlinuz
+IMAGE_riscv   = arch/riscv/boot/Image
+IMAGE         = $(IMAGE_$(ARCH))
+IMAGE_NAME    = $(notdir $(IMAGE))
+
+# default kernel configurations that appear to be usable
+DEFCONFIG_i386    = defconfig
+DEFCONFIG_x86     = defconfig
+DEFCONFIG_arm64   = defconfig
+DEFCONFIG_arm     = multi_v7_defconfig
+DEFCONFIG_mips    = malta_defconfig
+DEFCONFIG_riscv   = defconfig
+DEFCONFIG         = $(DEFCONFIG_$(ARCH))
+
+# optional tests to run (default = all)
+TEST =
+
+# QEMU_ARCH: arch names used by qemu
+QEMU_ARCH_i386    = i386
+QEMU_ARCH_x86     = x86_64
+QEMU_ARCH_arm64   = aarch64
+QEMU_ARCH_arm     = arm
+QEMU_ARCH_mips    = mipsel  # works with malta_defconfig
+QEMU_ARCH_riscv   = riscv64
+QEMU_ARCH         = $(QEMU_ARCH_$(ARCH))
+
+# QEMU_ARGS : some arch-specific args to pass to qemu
+QEMU_ARGS_i386    = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(TEST:%=NOLIBC_TEST=%)"
+QEMU_ARGS_x86     = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(TEST:%=NOLIBC_TEST=%)"
+QEMU_ARGS_arm64   = -M virt -cpu cortex-a53 -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
+QEMU_ARGS_arm     = -M virt -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
+QEMU_ARGS_mips    = -M malta -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
+QEMU_ARGS_riscv   = -M virt -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
+QEMU_ARGS         = $(QEMU_ARGS_$(ARCH))
+
+# OUTPUT is only set when run from the main makefile, otherwise
+# it defaults to this nolibc directory.
+OUTPUT ?= $(CURDIR)/
+
+ifeq ($(V),1)
+Q=
+else
+Q=@
+endif
+
+CFLAGS  ?= -Os -fno-ident -fno-asynchronous-unwind-tables
+LDFLAGS := -s
+
+help:
+	@echo "Supported targets under selftests/nolibc:"
+	@echo "  all          call the \"run\" target below"
+	@echo "  help         this help"
+	@echo "  sysroot      create the nolibc sysroot here (uses \$$ARCH)"
+	@echo "  nolibc-test  build the executable (uses \$$CC and \$$CROSS_COMPILE)"
+	@echo "  initramfs    prepare the initramfs with nolibc-test"
+	@echo "  defconfig    create a fresh new default config (uses \$$ARCH)"
+	@echo "  kernel       (re)build the kernel with the initramfs (uses \$$ARCH)"
+	@echo "  run          runs the kernel in QEMU after building it (uses \$$ARCH, \$$TEST)"
+	@echo "  rerun        runs a previously prebuilt kernel in QEMU (uses \$$ARCH, \$$TEST)"
+	@echo "  clean        clean the sysroot, initramfs, build and output files"
+	@echo ""
+	@echo "The output file is \"run.out\". Test ranges may be passed using \$$TEST."
+	@echo ""
+	@echo "Currently using the following variables:"
+	@echo "  ARCH          = $(ARCH)"
+	@echo "  CROSS_COMPILE = $(CROSS_COMPILE)"
+	@echo "  CC            = $(CC)"
+	@echo "  OUTPUT        = $(OUTPUT)"
+	@echo "  TEST          = $(TEST)"
+	@echo "  QEMU_ARCH     = $(if $(QEMU_ARCH),$(QEMU_ARCH),UNKNOWN_ARCH) [determined from \$$ARCH]"
+	@echo "  IMAGE_NAME    = $(if $(IMAGE_NAME),$(IMAGE_NAME),UNKNOWN_ARCH) [determined from \$$ARCH]"
+	@echo ""
+
+all: run
+
+sysroot: sysroot/$(ARCH)/include
+
+sysroot/$(ARCH)/include:
+	$(QUIET_MKDIR)mkdir -p sysroot
+	$(Q)$(MAKE) -C ../../../include/nolibc ARCH=$(ARCH) OUTPUT=$(CURDIR)/sysroot/ headers_standalone
+	$(Q)mv sysroot/sysroot sysroot/$(ARCH)
+
+nolibc-test: nolibc-test.c sysroot/$(ARCH)/include
+	$(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \
+	  -nostdlib -static -Isysroot/$(ARCH)/include $< -lgcc
+
+initramfs: nolibc-test
+	$(QUIET_MKDIR)mkdir -p initramfs
+	$(call QUIET_INSTALL, initramfs/init)
+	$(Q)cp nolibc-test initramfs/init
+
+defconfig:
+	$(Q)$(MAKE) -C $(srctree) ARCH=$(ARCH) CC=$(CC) CROSS_COMPILE=$(CROSS_COMPILE) mrproper $(DEFCONFIG) prepare
+
+kernel: initramfs
+	$(Q)$(MAKE) -C $(srctree) ARCH=$(ARCH) CC=$(CC) CROSS_COMPILE=$(CROSS_COMPILE) $(IMAGE_NAME) CONFIG_INITRAMFS_SOURCE=$(CURDIR)/initramfs
+
+# run the tests after building the kernel
+run: kernel
+	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(srctree)/$(IMAGE)" -serial stdio $(QEMU_ARGS) > "$(CURDIR)/run.out"
+	$(Q)grep -w FAIL "$(CURDIR)/run.out" && echo "See all results in $(CURDIR)/run.out" || echo "$$(grep -c ^[0-9].*OK $(CURDIR)/run.out) test(s) passed."
+
+# re-run the tests from an existing kernel
+rerun:
+	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(srctree)/$(IMAGE)" -serial stdio $(QEMU_ARGS) > "$(CURDIR)/run.out"
+	$(Q)grep -w FAIL "$(CURDIR)/run.out" && echo "See all results in $(CURDIR)/run.out" || echo "$$(grep -c ^[0-9].*OK $(CURDIR)/run.out) test(s) passed."
+
+clean:
+	$(call QUIET_CLEAN, sysroot)
+	$(Q)rm -rf sysroot
+	$(call QUIET_CLEAN, nolibc-test)
+	$(Q)rm -f nolibc-test
+	$(call QUIET_CLEAN, initramfs)
+	$(Q)rm -rf initramfs
+	$(call QUIET_CLEAN, run.out)
+	$(Q)rm -rf run.out