Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git

# Conflicts:
#	arch/loongarch/Kconfig

31 files changed, 1701 insertions, 131 deletions

diff --git a/tools/Makefile b/tools/Makefile
index c074e42fd92f..e497875fc7e3 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -78,6 +78,9 @@ bpf/%: FORCE
 libapi: FORCE
 	$(call descend,lib/api)
 
+nolibc: FORCE
+	$(call descend,include/nolibc)
+
 nolibc_%: FORCE
 	$(call descend,include/nolibc,$(patsubst nolibc_%,%,$@))
 
diff --git a/tools/include/nolibc/Makefile b/tools/include/nolibc/Makefile
index 7a16d917c185..cfd06764b5ae 100644
--- a/tools/include/nolibc/Makefile
+++ b/tools/include/nolibc/Makefile
@@ -7,13 +7,46 @@ ifeq ($(srctree),)
 srctree := $(patsubst %/tools/include/,%,$(dir $(CURDIR)))
 endif
 
+# when run as make -C tools/ nolibc_<foo> the arch is not set
+ifeq ($(ARCH),)
+include $(srctree)/scripts/subarch.include
+ARCH = $(SUBARCH)
+endif
+
+# 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
+
 nolibc_arch := $(patsubst arm64,aarch64,$(ARCH))
 arch_file := arch-$(nolibc_arch).h
 all_files := ctype.h errno.h nolibc.h signal.h std.h stdio.h stdlib.h string.h \
              sys.h time.h types.h unistd.h
 
 # install all headers needed to support a bare-metal compiler
-all:
+all: headers
+
+install: help
+
+help:
+	@echo "Supported targets under nolibc:"
+	@echo "  all                 call \"headers\""
+	@echo "  clean               clean the sysroot"
+	@echo "  headers             prepare a sysroot in tools/include/nolibc/sysroot"
+	@echo "  headers_standalone  like \"headers\", and also install kernel headers"
+	@echo "  help                this help"
+	@echo ""
+	@echo "These targets may also be called from tools as \"make nolibc_<target>\"."
+	@echo ""
+	@echo "Currently using the following variables:"
+	@echo "  ARCH    = $(ARCH)"
+	@echo "  OUTPUT  = $(OUTPUT)"
+	@echo ""
 
 # Note: when ARCH is "x86" we concatenate both x86_64 and i386
 headers:
@@ -36,7 +69,7 @@ headers:
 
 headers_standalone: headers
 	$(Q)$(MAKE) -C $(srctree) headers
-	$(Q)$(MAKE) -C $(srctree) headers_install INSTALL_HDR_PATH=$(OUTPUT)/sysroot
+	$(Q)$(MAKE) -C $(srctree) headers_install INSTALL_HDR_PATH=$(OUTPUT)sysroot
 
 clean:
 	$(call QUIET_CLEAN, nolibc) rm -rf "$(OUTPUT)sysroot"
diff --git a/tools/include/nolibc/arch-riscv.h b/tools/include/nolibc/arch-riscv.h
index 95e2b7924925..ba04771cb3a3 100644
--- a/tools/include/nolibc/arch-riscv.h
+++ b/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)
diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h
index 15dedf8d0902..a3cebc4bc3ac 100644
--- a/tools/include/nolibc/stdio.h
+++ b/tools/include/nolibc/stdio.h
@@ -273,7 +273,7 @@ int vfprintf(FILE *stream, const char *fmt, va_list args)
 	return written;
 }
 
-static __attribute__((unused))
+static __attribute__((unused, format(printf, 2, 3)))
 int fprintf(FILE *stream, const char *fmt, ...)
 {
 	va_list args;
@@ -285,7 +285,7 @@ int fprintf(FILE *stream, const char *fmt, ...)
 	return ret;
 }
 
-static __attribute__((unused))
+static __attribute__((unused, format(printf, 1, 2)))
 int printf(const char *fmt, ...)
 {
 	va_list args;
diff --git a/tools/include/nolibc/stdlib.h b/tools/include/nolibc/stdlib.h
index 8fd32eaf8037..92378c4b9660 100644
--- a/tools/include/nolibc/stdlib.h
+++ b/tools/include/nolibc/stdlib.h
@@ -128,10 +128,9 @@ void *malloc(size_t len)
 static __attribute__((unused))
 void *calloc(size_t size, size_t nmemb)
 {
-	void *orig;
-	size_t res = 0;
+	size_t x = size * nmemb;
 
-	if (__builtin_expect(__builtin_mul_overflow(nmemb, size, &res), 0)) {
+	if (__builtin_expect(size && ((x / size) != nmemb), 0)) {
 		SET_ERRNO(ENOMEM);
 		return NULL;
 	}
@@ -140,7 +139,7 @@ void *calloc(size_t size, size_t nmemb)
 	 * No need to zero the heap, the MAP_ANONYMOUS in malloc()
 	 * already does it.
 	 */
-	return malloc(res);
+	return malloc(x);
 }
 
 static __attribute__((unused))
diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
index 08491070387b..ce3ee03aa679 100644
--- a/tools/include/nolibc/sys.h
+++ b/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
diff --git a/tools/memory-model/Documentation/litmus-tests.txt b/tools/memory-model/Documentation/litmus-tests.txt
index 8a9d5d2787f9..cc355999815c 100644
--- a/tools/memory-model/Documentation/litmus-tests.txt
+++ b/tools/memory-model/Documentation/litmus-tests.txt
@@ -946,22 +946,39 @@ Limitations of the Linux-kernel memory model (LKMM) include:
 	carrying a dependency, then the compiler can break that dependency
 	by substituting a constant of that value.
 
-	Conversely, LKMM sometimes doesn't recognize that a particular
-	optimization is not allowed, and as a result, thinks that a
-	dependency is not present (because the optimization would break it).
-	The memory model misses some pretty obvious control dependencies
-	because of this limitation.  A simple example is:
+	Conversely, LKMM will sometimes overestimate the amount of
+	reordering compilers and CPUs can carry out, leading it to miss
+	some pretty obvious cases of ordering.  A simple example is:
 
 		r1 = READ_ONCE(x);
 		if (r1 == 0)
 			smp_mb();
 		WRITE_ONCE(y, 1);
 
-	There is a control dependency from the READ_ONCE to the WRITE_ONCE,
-	even when r1 is nonzero, but LKMM doesn't realize this and thinks
-	that the write may execute before the read if r1 != 0.  (Yes, that
-	doesn't make sense if you think about it, but the memory model's
-	intelligence is limited.)
+	The WRITE_ONCE() does not depend on the READ_ONCE(), and as a
+	result, LKMM does not claim ordering.  However, even though no
+	dependency is present, the WRITE_ONCE() will not be executed before
+	the READ_ONCE().  There are two reasons for this:
+
+                The presence of the smp_mb() in one of the branches
+                prevents the compiler from moving the WRITE_ONCE()
+                up before the "if" statement, since the compiler has
+                to assume that r1 will sometimes be 0 (but see the
+                comment below);
+
+                CPUs do not execute stores before po-earlier conditional
+                branches, even in cases where the store occurs after the
+                two arms of the branch have recombined.
+
+	It is clear that it is not dangerous in the slightest for LKMM to
+	make weaker guarantees than architectures.  In fact, it is
+	desirable, as it gives compilers room for making optimizations.  
+	For instance, suppose that a 0 value in r1 would trigger undefined
+	behavior elsewhere.  Then a clever compiler might deduce that r1
+	can never be 0 in the if condition.  As a result, said clever
+	compiler might deem it safe to optimize away the smp_mb(),
+	eliminating the branch and any ordering an architecture would
+	guarantee otherwise.
 
 2.	Multiple access sizes for a single variable are not supported,
 	and neither are misaligned or partially overlapping accesses.
diff --git a/tools/memory-model/Documentation/locking.txt b/tools/memory-model/Documentation/locking.txt
new file mode 100644
index 000000000000..4e05c6d53ab7
--- /dev/null
+++ b/tools/memory-model/Documentation/locking.txt
@@ -0,0 +1,320 @@
+Locking
+=======
+
+Locking is well-known and the common use cases are straightforward: Any
+CPU holding a given lock sees any changes previously seen or made by any
+CPU before it previously released that same lock.  This last sentence
+is the only part of this document that most developers will need to read.
+
+However, developers who would like to also access lock-protected shared
+variables outside of their corresponding locks should continue reading.
+
+
+Locking and Prior Accesses
+--------------------------
+
+The basic rule of locking is worth repeating:
+
+	Any CPU holding a given lock sees any changes previously seen
+	or made by any CPU before it previously released that same lock.
+
+Note that this statement is a bit stronger than "Any CPU holding a
+given lock sees all changes made by any CPU during the time that CPU was
+previously holding this same lock".  For example, consider the following
+pair of code fragments:
+
+	/* See MP+polocks.litmus. */
+	void CPU0(void)
+	{
+		WRITE_ONCE(x, 1);
+		spin_lock(&mylock);
+		WRITE_ONCE(y, 1);
+		spin_unlock(&mylock);
+	}
+
+	void CPU1(void)
+	{
+		spin_lock(&mylock);
+		r0 = READ_ONCE(y);
+		spin_unlock(&mylock);
+		r1 = READ_ONCE(x);
+	}
+
+The basic rule guarantees that if CPU0() acquires mylock before CPU1(),
+then both r0 and r1 must be set to the value 1.  This also has the
+consequence that if the final value of r0 is equal to 1, then the final
+value of r1 must also be equal to 1.  In contrast, the weaker rule would
+say nothing about the final value of r1.
+
+
+Locking and Subsequent Accesses
+-------------------------------
+
+The converse to the basic rule also holds:  Any CPU holding a given
+lock will not see any changes that will be made by any CPU after it
+subsequently acquires this same lock.  This converse statement is
+illustrated by the following litmus test:
+
+	/* See MP+porevlocks.litmus. */
+	void CPU0(void)
+	{
+		r0 = READ_ONCE(y);
+		spin_lock(&mylock);
+		r1 = READ_ONCE(x);
+		spin_unlock(&mylock);
+	}
+
+	void CPU1(void)
+	{
+		spin_lock(&mylock);
+		WRITE_ONCE(x, 1);
+		spin_unlock(&mylock);
+		WRITE_ONCE(y, 1);
+	}
+
+This converse to the basic rule guarantees that if CPU0() acquires
+mylock before CPU1(), then both r0 and r1 must be set to the value 0.
+This also has the consequence that if the final value of r1 is equal
+to 0, then the final value of r0 must also be equal to 0.  In contrast,
+the weaker rule would say nothing about the final value of r0.
+
+These examples show only a single pair of CPUs, but the effects of the
+locking basic rule extend across multiple acquisitions of a given lock
+across multiple CPUs.
+
+
+Double-Checked Locking
+----------------------
+
+It is well known that more than just a lock is required to make
+double-checked locking work correctly,  This litmus test illustrates
+one incorrect approach:
+
+	/* See Documentation/litmus-tests/locking/DCL-broken.litmus. */
+	P0(int *flag, int *data, int *lck)
+	{
+		int r0;
+		int r1;
+		int r2;
+
+		r0 = READ_ONCE(*flag);
+		if (r0 == 0) {
+			spin_lock(lck);
+			r1 = READ_ONCE(*flag);
+			if (r1 == 0) {
+				WRITE_ONCE(*data, 1);
+				WRITE_ONCE(*flag, 1);
+			}
+			spin_unlock(lck);
+		}
+		r2 = READ_ONCE(*data);
+	}
+	/* P1() is the exactly the same as P0(). */
+
+There are two problems.  First, there is no ordering between the first
+READ_ONCE() of "flag" and the READ_ONCE() of "data".  Second, there is
+no ordering between the two WRITE_ONCE() calls.  It should therefore be
+no surprise that "r2" can be zero, and a quick herd7 run confirms this.
+
+One way to fix this is to use smp_load_acquire() and smp_store_release()
+as shown in this corrected version:
+
+	/* See Documentation/litmus-tests/locking/DCL-fixed.litmus. */
+	P0(int *flag, int *data, int *lck)
+	{
+		int r0;
+		int r1;
+		int r2;
+
+		r0 = smp_load_acquire(flag);
+		if (r0 == 0) {
+			spin_lock(lck);
+			r1 = READ_ONCE(*flag);
+			if (r1 == 0) {
+				WRITE_ONCE(*data, 1);
+				smp_store_release(flag, 1);
+			}
+			spin_unlock(lck);
+		}
+		r2 = READ_ONCE(*data);
+	}
+	/* P1() is the exactly the same as P0(). */
+
+The smp_load_acquire() guarantees that its load from "flags" will
+be ordered before the READ_ONCE() from data, thus solving the first
+problem.  The smp_store_release() guarantees that its store will be
+ordered after the WRITE_ONCE() to "data", solving the second problem.
+The smp_store_release() pairs with the smp_load_acquire(), thus ensuring
+that the ordering provided by each actually takes effect.  Again, a
+quick herd7 run confirms this.
+
+In short, if you access a lock-protected variable without holding the
+corresponding lock, you will need to provide additional ordering, in
+this case, via the smp_load_acquire() and the smp_store_release().
+
+
+Ordering Provided by a Lock to CPUs Not Holding That Lock
+---------------------------------------------------------
+
+It is not necessarily the case that accesses ordered by locking will be
+seen as ordered by CPUs not holding that lock.  Consider this example:
+
+	/* See Z6.0+pooncelock+pooncelock+pombonce.litmus. */
+	void CPU0(void)
+	{
+		spin_lock(&mylock);
+		WRITE_ONCE(x, 1);
+		WRITE_ONCE(y, 1);
+		spin_unlock(&mylock);
+	}
+
+	void CPU1(void)
+	{
+		spin_lock(&mylock);
+		r0 = READ_ONCE(y);
+		WRITE_ONCE(z, 1);
+		spin_unlock(&mylock);
+	}
+
+	void CPU2(void)
+	{
+		WRITE_ONCE(z, 2);
+		smp_mb();
+		r1 = READ_ONCE(x);
+	}
+
+Counter-intuitive though it might be, it is quite possible to have
+the final value of r0 be 1, the final value of z be 2, and the final
+value of r1 be 0.  The reason for this surprising outcome is that CPU2()
+never acquired the lock, and thus did not fully benefit from the lock's
+ordering properties.
+
+Ordering can be extended to CPUs not holding the lock by careful use
+of smp_mb__after_spinlock():
+
+	/* See Z6.0+pooncelock+poonceLock+pombonce.litmus. */
+	void CPU0(void)
+	{
+		spin_lock(&mylock);
+		WRITE_ONCE(x, 1);
+		WRITE_ONCE(y, 1);
+		spin_unlock(&mylock);
+	}
+
+	void CPU1(void)
+	{
+		spin_lock(&mylock);
+		smp_mb__after_spinlock();
+		r0 = READ_ONCE(y);
+		WRITE_ONCE(z, 1);
+		spin_unlock(&mylock);
+	}
+
+	void CPU2(void)
+	{
+		WRITE_ONCE(z, 2);
+		smp_mb();
+		r1 = READ_ONCE(x);
+	}
+
+This addition of smp_mb__after_spinlock() strengthens the lock
+acquisition sufficiently to rule out the counter-intuitive outcome.
+In other words, the addition of the smp_mb__after_spinlock() prohibits
+the counter-intuitive result where the final value of r0 is 1, the final
+value of z is 2, and the final value of r1 is 0.
+
+
+No Roach-Motel Locking!
+-----------------------
+
+This example requires familiarity with the herd7 "filter" clause, so
+please read up on that topic in litmus-tests.txt.
+
+It is tempting to allow memory-reference instructions to be pulled
+into a critical section, but this cannot be allowed in the general case.
+For example, consider a spin loop preceding a lock-based critical section.
+Now, herd7 does not model spin loops, but we can emulate one with two
+loads, with a "filter" clause to constrain the first to return the
+initial value and the second to return the updated value, as shown below:
+
+	/* See Documentation/litmus-tests/locking/RM-fixed.litmus. */
+	P0(int *x, int *y, int *lck)
+	{
+		int r2;
+
+		spin_lock(lck);
+		r2 = atomic_inc_return(y);
+		WRITE_ONCE(*x, 1);
+		spin_unlock(lck);
+	}
+
+	P1(int *x, int *y, int *lck)
+	{
+		int r0;
+		int r1;
+		int r2;
+
+		r0 = READ_ONCE(*x);
+		r1 = READ_ONCE(*x);
+		spin_lock(lck);
+		r2 = atomic_inc_return(y);
+		spin_unlock(lck);
+	}
+
+	filter (y=2 /\ 1:r0=0 /\ 1:r1=1)
+	exists (1:r2=1)
+
+The variable "x" is the control variable for the emulated spin loop.
+P0() sets it to "1" while holding the lock, and P1() emulates the
+spin loop by reading it twice, first into "1:r0" (which should get the
+initial value "0") and then into "1:r1" (which should get the updated
+value "1").
+
+The purpose of the variable "y" is to reject deadlocked executions.
+Only those executions where the final value of "y" have avoided deadlock.
+
+The "filter" clause takes all this into account, constraining "y" to
+equal "2", "1:r0" to equal "0", and "1:r1" to equal 1.
+
+Then the "exists" clause checks to see if P1() acquired its lock first,
+which should not happen given the filter clause because P0() updates
+"x" while holding the lock.  And herd7 confirms this.
+
+But suppose that the compiler was permitted to reorder the spin loop
+into P1()'s critical section, like this:
+
+	/* See Documentation/litmus-tests/locking/RM-broken.litmus. */
+	P0(int *x, int *y, int *lck)
+	{
+		int r2;
+
+		spin_lock(lck);
+		r2 = atomic_inc_return(y);
+		WRITE_ONCE(*x, 1);
+		spin_unlock(lck);
+	}
+
+	P1(int *x, int *y, int *lck)
+	{
+		int r0;
+		int r1;
+		int r2;
+
+		spin_lock(lck);
+		r0 = READ_ONCE(*x);
+		r1 = READ_ONCE(*x);
+		r2 = atomic_inc_return(y);
+		spin_unlock(lck);
+	}
+
+	locations [x;lck;0:r2;1:r0;1:r1;1:r2]
+	filter (y=2 /\ 1:r0=0 /\ 1:r1=1)
+	exists (1:r2=1)
+
+If "1:r0" is equal to "0", "1:r1" can never equal "1" because P0()
+cannot update "x" while P1() holds the lock.  And herd7 confirms this,
+showing zero executions matching the "filter" criteria.
+
+And this is why Linux-kernel lock and unlock primitives must prevent
+code from entering critical sections.  It is not sufficient to only
+prevent code from leaving them.
diff --git a/tools/memory-model/linux-kernel.bell b/tools/memory-model/linux-kernel.bell
index 5be86b1025e8..65c32ca9d5ea 100644
--- a/tools/memory-model/linux-kernel.bell
+++ b/tools/memory-model/linux-kernel.bell
@@ -56,17 +56,11 @@ let rcu-rscs = let rec
 flag ~empty Rcu-lock \ domain(rcu-rscs) as unbalanced-rcu-locking
 flag ~empty Rcu-unlock \ range(rcu-rscs) as unbalanced-rcu-locking
 
-(* Compute matching pairs of nested Srcu-lock and Srcu-unlock *)
-let srcu-rscs = let rec
-	    unmatched-locks = Srcu-lock \ domain(matched)
-	and unmatched-unlocks = Srcu-unlock \ range(matched)
-	and unmatched = unmatched-locks | unmatched-unlocks
-	and unmatched-po = ([unmatched] ; po ; [unmatched]) & loc
-	and unmatched-locks-to-unlocks =
-		([unmatched-locks] ; po ; [unmatched-unlocks]) & loc
-	and matched = matched | (unmatched-locks-to-unlocks \
-		(unmatched-po ; unmatched-po))
-	in matched
+(* Compute matching pairs of Srcu-lock and Srcu-unlock, but prohibit nesting *)
+let srcu-unmatched = Srcu-lock | Srcu-unlock
+let srcu-unmatched-po = ([srcu-unmatched] ; po ; [srcu-unmatched]) & loc
+let srcu-unmatched-locks-to-unlock = ([Srcu-lock] ; po ; [Srcu-unlock]) & loc
+let srcu-rscs = srcu-unmatched-locks-to-unlock \ (srcu-unmatched-po ; srcu-unmatched-po)
 
 (* Validate nesting *)
 flag ~empty Srcu-lock \ domain(srcu-rscs) as unbalanced-srcu-locking
diff --git a/tools/memory-model/litmus-tests/.gitignore b/tools/memory-model/litmus-tests/.gitignore
index c492a1ddad91..19c379cf069d 100644
--- a/tools/memory-model/litmus-tests/.gitignore
+++ b/tools/memory-model/litmus-tests/.gitignore
@@ -1,2 +1,2 @@
 # SPDX-License-Identifier: GPL-2.0-only
-*.litmus.out
+*.litmus.*
diff --git a/tools/memory-model/scripts/README b/tools/memory-model/scripts/README
index 095c7eb36f9f..cc2c4e5be9ec 100644
--- a/tools/memory-model/scripts/README
+++ b/tools/memory-model/scripts/README
@@ -27,6 +27,14 @@ checklitmushist.sh
 checklitmus.sh
 
 	Check a single litmus test against its "Result:" expected result.
+	Not intended to for manual use.
+
+checktheselitmus.sh
+
+	Check the specified list of litmus tests against their "Result:"
+	expected results.  This takes optional parseargs.sh arguments,
+	followed by "--" followed by pathnames starting from the current
+	directory.
 
 cmplitmushist.sh
 
@@ -43,10 +51,10 @@ initlitmushist.sh
 
 judgelitmus.sh
 
-	Given a .litmus file and its .litmus.out herd7 output, check the
-	.litmus.out file against the .litmus file's "Result:" comment to
-	judge whether the test ran correctly.  Not normally run manually,
-	provided instead for use by other scripts.
+	Given a .litmus file and its herd7 output, check the output file
+	against the .litmus file's "Result:" comment to judge whether
+	the test ran correctly.  Not normally run manually, provided
+	instead for use by other scripts.
 
 newlitmushist.sh
 
diff --git a/tools/memory-model/scripts/checkalllitmus.sh b/tools/memory-model/scripts/checkalllitmus.sh
index 3c0c7fbbd223..2d3ee850a839 100755
--- a/tools/memory-model/scripts/checkalllitmus.sh
+++ b/tools/memory-model/scripts/checkalllitmus.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 # SPDX-License-Identifier: GPL-2.0+
 #
 # Run herd7 tests on all .litmus files in the litmus-tests directory
@@ -8,6 +8,11 @@
 # "^^^".  It also outputs verification results to a file whose name is
 # that of the specified litmus test, but with ".out" appended.
 #
+# If the --hw argument is specified, this script translates the .litmus
+# C-language file to the specified type of assembly and verifies that.
+# But in this case, litmus tests using complex synchronization (such as
+# locking, RCU, and SRCU) are cheerfully ignored.
+#
 # Usage:
 #	checkalllitmus.sh
 #
@@ -17,7 +22,7 @@
 #
 # Copyright IBM Corporation, 2018
 #
-# Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+# Author: Paul E. McKenney <paulmck@linux.ibm.com>
 
 . scripts/parseargs.sh
 
@@ -30,29 +35,23 @@ else
 	exit 255
 fi
 
-# Create any new directories that have appeared in the github litmus
-# repo since the last run.
+# Create any new directories that have appeared in the litmus-tests
+# directory since the last run.
 if test "$LKMM_DESTDIR" != "."
 then
 	find $litmusdir -type d -print |
 	( cd "$LKMM_DESTDIR"; sed -e 's/^/mkdir -p /' | sh )
 fi
 
-# Find the checklitmus script.  If it is not where we expect it, then
-# assume that the caller has the PATH environment variable set
-# appropriately.
-if test -x scripts/checklitmus.sh
-then
-	clscript=scripts/checklitmus.sh
-else
-	clscript=checklitmus.sh
-fi
-
 # Run the script on all the litmus tests in the specified directory
 ret=0
 for i in $litmusdir/*.litmus
 do
-	if ! $clscript $i
+	if test -n "$LKMM_HW_MAP_FILE" && ! scripts/simpletest.sh $i
+	then
+		continue
+	fi
+	if ! scripts/checklitmus.sh $i
 	then
 		ret=1
 	fi
diff --git a/tools/memory-model/scripts/checkghlitmus.sh b/tools/memory-model/scripts/checkghlitmus.sh
index 6589fbb6f653..cedd0290b73f 100755
--- a/tools/memory-model/scripts/checkghlitmus.sh
+++ b/tools/memory-model/scripts/checkghlitmus.sh
@@ -10,6 +10,7 @@
 # parseargs.sh scripts for arguments.
 
 . scripts/parseargs.sh
+. scripts/hwfnseg.sh
 
 T=/tmp/checkghlitmus.sh.$$
 trap 'rm -rf $T' 0
@@ -32,19 +33,19 @@ then
 	( cd "$LKMM_DESTDIR"; sed -e 's/^/mkdir -p /' | sh )
 fi
 
-# Create a list of the C-language litmus tests previously run.
-( cd $LKMM_DESTDIR; find litmus -name '*.litmus.out' -print ) |
-	sed -e 's/\.out$//' |
+# Create a list of the specified litmus tests previously run.
+( cd $LKMM_DESTDIR; find litmus -name "*.litmus${hwfnseg}.out" -print ) |
+	sed -e "s/${hwfnseg}"'\.out$//' |
 	xargs -r egrep -l '^ \* Result: (Never|Sometimes|Always|DEADLOCK)' |
 	xargs -r grep -L "^P${LKMM_PROCS}"> $T/list-C-already
 
 # Create a list of C-language litmus tests with "Result:" commands and
 # no more than the specified number of processes.
-find litmus -name '*.litmus' -exec grep -l -m 1 "^C " {} \; > $T/list-C
+find litmus -name '*.litmus' -print | mselect7 -arch C > $T/list-C
 xargs < $T/list-C -r egrep -l '^ \* Result: (Never|Sometimes|Always|DEADLOCK)' > $T/list-C-result
 xargs < $T/list-C-result -r grep -L "^P${LKMM_PROCS}" > $T/list-C-result-short
 
-# Form list of tests without corresponding .litmus.out files
+# Form list of tests without corresponding .out files
 sort $T/list-C-already $T/list-C-result-short | uniq -u > $T/list-C-needed
 
 # Run any needed tests.
diff --git a/tools/memory-model/scripts/checklitmus.sh b/tools/memory-model/scripts/checklitmus.sh
index 11461ed40b5e..4c1d0cf0ddad 100755
--- a/tools/memory-model/scripts/checklitmus.sh
+++ b/tools/memory-model/scripts/checklitmus.sh
@@ -1,10 +1,8 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0+
 #
-# Run a herd7 test and invokes judgelitmus.sh to check the result against
-# a "Result:" comment within the litmus test.  It also outputs verification
-# results to a file whose name is that of the specified litmus test, but
-# with ".out" appended.
+# Invokes runlitmus.sh and judgelitmus.sh on its arguments to run the
+# specified litmus test and pass judgment on the results.
 #
 # Usage:
 #	checklitmus.sh file.litmus
@@ -15,20 +13,7 @@
 #
 # Copyright IBM Corporation, 2018
 #
-# Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+# Author: Paul E. McKenney <paulmck@linux.ibm.com>
 
-litmus=$1
-herdoptions=${LKMM_HERD_OPTIONS--conf linux-kernel.cfg}
-
-if test -f "$litmus" -a -r "$litmus"
-then
-	:
-else
-	echo ' --- ' error: \"$litmus\" is not a readable file
-	exit 255
-fi
-
-echo Herd options: $herdoptions > $LKMM_DESTDIR/$litmus.out
-/usr/bin/time $LKMM_TIMEOUT_CMD herd7 $herdoptions $litmus >> $LKMM_DESTDIR/$litmus.out 2>&1
-
-scripts/judgelitmus.sh $litmus
+scripts/runlitmus.sh $1
+scripts/judgelitmus.sh $1
diff --git a/tools/memory-model/scripts/checklitmushist.sh b/tools/memory-model/scripts/checklitmushist.sh
index 1d210ffb7c8a..406ecfc0aee4 100755
--- a/tools/memory-model/scripts/checklitmushist.sh
+++ b/tools/memory-model/scripts/checklitmushist.sh
@@ -12,7 +12,7 @@
 #
 # Copyright IBM Corporation, 2018
 #
-# Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+# Author: Paul E. McKenney <paulmck@linux.ibm.com>
 
 . scripts/parseargs.sh
 
diff --git a/tools/memory-model/scripts/checktheselitmus.sh b/tools/memory-model/scripts/checktheselitmus.sh
new file mode 100755
index 000000000000..10eeb5ecea6d
--- /dev/null
+++ b/tools/memory-model/scripts/checktheselitmus.sh
@@ -0,0 +1,43 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Invokes checklitmus.sh on its arguments to run the specified litmus
+# test and pass judgment on the results.
+#
+# Usage:
+#	checktheselitmus.sh -- [ file1.litmus [ file2.litmus ... ] ]
+#
+# Run this in the directory containing the memory model, specifying the
+# pathname of the litmus test to check.  The usual parseargs.sh arguments
+# can be specified prior to the "--".
+#
+# This script is intended for use with pathnames that start from the
+# tools/memory-model directory.  If some of the pathnames instead start at
+# the root directory, they all must do so and the "--destdir /" parseargs.sh
+# argument must be specified prior to the "--".  Alternatively, some other
+# "--destdir" argument can be supplied as long as the needed subdirectories
+# are populated.
+#
+# Copyright IBM Corporation, 2018
+#
+# Author: Paul E. McKenney <paulmck@linux.ibm.com>
+
+. scripts/parseargs.sh
+
+ret=0
+for i in "$@"
+do
+	if scripts/checklitmus.sh $i
+	then
+		:
+	else
+		ret=1
+	fi
+done
+if test "$ret" -ne 0
+then
+	echo " ^^^ VERIFICATION MISMATCHES" 1>&2
+else
+	echo All litmus tests verified as was expected. 1>&2
+fi
+exit $ret
diff --git a/tools/memory-model/scripts/cmplitmushist.sh b/tools/memory-model/scripts/cmplitmushist.sh
index 0f498aeeccf5..ca1ac8b64614 100755
--- a/tools/memory-model/scripts/cmplitmushist.sh
+++ b/tools/memory-model/scripts/cmplitmushist.sh
@@ -12,12 +12,49 @@ trap 'rm -rf $T' 0
 mkdir $T
 
 # comparetest oldpath newpath
+badmacnam=0
+timedout=0
 perfect=0
 obsline=0
 noobsline=0
 obsresult=0
 badcompare=0
 comparetest () {
+	if grep -q ': Unknown macro ' $1 || grep -q ': Unknown macro ' $2
+	then
+		if grep -q ': Unknown macro ' $1
+		then
+			badname=`grep ': Unknown macro ' $1 |
+				sed -e 's/^.*: Unknown macro //' |
+				sed -e 's/ (User error).*$//'`
+			echo 'Current LKMM version does not know "'$badname'"' $1
+		fi
+		if grep -q ': Unknown macro ' $2
+		then
+			badname=`grep ': Unknown macro ' $2 |
+				sed -e 's/^.*: Unknown macro //' |
+				sed -e 's/ (User error).*$//'`
+			echo 'Current LKMM version does not know "'$badname'"' $2
+		fi
+		badmacnam=`expr "$badmacnam" + 1`
+		return 0
+	elif grep -q '^Command exited with non-zero status 124' $1 ||
+	     grep -q '^Command exited with non-zero status 124' $2
+	then
+		if grep -q '^Command exited with non-zero status 124' $1 &&
+		   grep -q '^Command exited with non-zero status 124' $2
+		then
+			echo Both runs timed out: $2
+		elif grep -q '^Command exited with non-zero status 124' $1
+		then
+			echo Old run timed out: $2
+		elif grep -q '^Command exited with non-zero status 124' $2
+		then
+			echo New run timed out: $2
+		fi
+		timedout=`expr "$timedout" + 1`
+		return 0
+	fi
 	grep -v 'maxresident)k\|minor)pagefaults\|^Time' $1 > $T/oldout
 	grep -v 'maxresident)k\|minor)pagefaults\|^Time' $2 > $T/newout
 	if cmp -s $T/oldout $T/newout && grep -q '^Observation' $1
@@ -38,7 +75,7 @@ comparetest () {
 			return 0
 		fi
 	else
-		echo Missing Observation line "(e.g., herd7 timeout)": $2
+		echo Missing Observation line "(e.g., syntax error)": $2
 		noobsline=`expr "$noobsline" + 1`
 		return 0
 	fi
@@ -72,12 +109,20 @@ then
 fi
 if test "$noobsline" -ne 0
 then
-	echo Missing Observation line "(e.g., herd7 timeout)": $noobsline 1>&2
+	echo Missing Observation line "(e.g., syntax error)": $noobsline 1>&2
 fi
 if test "$obsresult" -ne 0
 then
 	echo Matching Observation Always/Sometimes/Never result: $obsresult 1>&2
 fi
+if test "$timedout" -ne 0
+then
+	echo "!!!" Timed out: $timedout 1>&2
+fi
+if test "$badmacnam" -ne 0
+then
+	echo "!!!" Unknown primitive: $badmacnam 1>&2
+fi
 if test "$badcompare" -ne 0
 then
 	echo "!!!" Result changed: $badcompare 1>&2
diff --git a/tools/memory-model/scripts/hwfnseg.sh b/tools/memory-model/scripts/hwfnseg.sh
new file mode 100755
index 000000000000..580c3281181c
--- /dev/null
+++ b/tools/memory-model/scripts/hwfnseg.sh
@@ -0,0 +1,20 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Generate the hardware extension to the litmus-test filename, or the
+# empty string if this is an LKMM run.  The extension is placed in
+# the shell variable hwfnseg.
+#
+# Usage:
+#	. hwfnseg.sh
+#
+# Copyright IBM Corporation, 2019
+#
+# Author: Paul E. McKenney <paulmck@linux.ibm.com>
+
+if test -z "$LKMM_HW_MAP_FILE"
+then
+	hwfnseg=
+else
+	hwfnseg=".$LKMM_HW_MAP_FILE"
+fi
diff --git a/tools/memory-model/scripts/initlitmushist.sh b/tools/memory-model/scripts/initlitmushist.sh
index 956b6957484d..31ea782955d3 100755
--- a/tools/memory-model/scripts/initlitmushist.sh
+++ b/tools/memory-model/scripts/initlitmushist.sh
@@ -60,7 +60,7 @@ fi
 
 # Create a list of the C-language litmus tests with no more than the
 # specified number of processes (per the --procs argument).
-find litmus -name '*.litmus' -exec grep -l -m 1 "^C " {} \; > $T/list-C
+find litmus -name '*.litmus' -print | mselect7 -arch C > $T/list-C
 xargs < $T/list-C -r grep -L "^P${LKMM_PROCS}" > $T/list-C-short
 
 scripts/runlitmushist.sh < $T/list-C-short
diff --git a/tools/memory-model/scripts/judgelitmus.sh b/tools/memory-model/scripts/judgelitmus.sh
index 0cc63875e395..1ec5d89fcfbb 100755
--- a/tools/memory-model/scripts/judgelitmus.sh
+++ b/tools/memory-model/scripts/judgelitmus.sh
@@ -1,9 +1,22 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0+
 #
-# Given a .litmus test and the corresponding .litmus.out file, check
-# the .litmus.out file against the "Result:" comment to judge whether
-# the test ran correctly.
+# Given a .litmus test and the corresponding litmus output file, check
+# the .litmus.out file against the "Result:" comment to judge whether the
+# test ran correctly.  If the --hw argument is omitted, check against the
+# LKMM output, which is assumed to be in file.litmus.out. If either a
+# "DATARACE" marker in the "Result:" comment or a "Flag data-race" marker
+# in the LKMM output is present, the other must also be as well, at least
+# for litmus tests having a "Result:" comment. In this case, a failure of
+# the Always/Sometimes/Never portion of the "Result:" prediction will be
+# noted, but forgiven.
+#
+# If the --hw argument is provided, this is assumed to be a hardware
+# test, and the output is assumed to be in file.litmus.HW.out, where
+# "HW" is the --hw argument. In addition, non-Sometimes verification
+# results will be noted, but forgiven.  Furthermore, if there is no
+# "Result:" comment but there is an LKMM .litmus.out file, the observation
+# in that file will be used to judge the assembly-language verification.
 #
 # Usage:
 #	judgelitmus.sh file.litmus
@@ -13,7 +26,7 @@
 #
 # Copyright IBM Corporation, 2018
 #
-# Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+# Author: Paul E. McKenney <paulmck@linux.ibm.com>
 
 litmus=$1
 
@@ -24,55 +37,120 @@ else
 	echo ' --- ' error: \"$litmus\" is not a readable file
 	exit 255
 fi
-if test -f "$LKMM_DESTDIR/$litmus".out -a -r "$LKMM_DESTDIR/$litmus".out
+if test -z "$LKMM_HW_MAP_FILE"
+then
+	litmusout=$litmus.out
+	lkmmout=
+else
+	litmusout="`echo $litmus |
+		sed -e 's/\.litmus$/.litmus.'${LKMM_HW_MAP_FILE}'/'`.out"
+	lkmmout=$litmus.out
+fi
+if test -f "$LKMM_DESTDIR/$litmusout" -a -r "$LKMM_DESTDIR/$litmusout"
 then
 	:
 else
-	echo ' --- ' error: \"$LKMM_DESTDIR/$litmus\".out is not a readable file
+	echo ' --- ' error: \"$LKMM_DESTDIR/$litmusout is not a readable file
 	exit 255
 fi
-if grep -q '^ \* Result: ' $litmus
+if grep -q '^Flag data-race$' "$LKMM_DESTDIR/$litmusout"
+then
+	datarace_modeled=1
+fi
+if grep -q '^[( ]\* Result: ' $litmus
+then
+	outcome=`grep -m 1 '^[( ]\* Result: ' $litmus | awk '{ print $3 }'`
+	if grep -m1 '^[( ]\* Result: .* DATARACE' $litmus
+	then
+		datarace_predicted=1
+	fi
+	if test -n "$datarace_predicted" -a -z "$datarace_modeled" -a -z "$LKMM_HW_MAP_FILE"
+	then
+		echo '!!! Predicted data race not modeled' $litmus
+		exit 252
+	elif test -z "$datarace_predicted" -a -n "$datarace_modeled"
+	then
+		# Note that hardware models currently don't model data races
+		echo '!!! Unexpected data race modeled' $litmus
+		exit 253
+	fi
+elif test -n "$LKMM_HW_MAP_FILE" && grep -q '^Observation' $LKMM_DESTDIR/$lkmmout > /dev/null 2>&1
 then
-	outcome=`grep -m 1 '^ \* Result: ' $litmus | awk '{ print $3 }'`
+	outcome=`grep -m 1 '^Observation ' $LKMM_DESTDIR/$lkmmout | awk '{ print $3 }'`
 else
 	outcome=specified
 fi
 
-grep '^Observation' $LKMM_DESTDIR/$litmus.out
-if grep -q '^Observation' $LKMM_DESTDIR/$litmus.out
+grep '^Observation' $LKMM_DESTDIR/$litmusout
+if grep -q '^Observation' $LKMM_DESTDIR/$litmusout
 then
 	:
+elif grep ': Unknown macro ' $LKMM_DESTDIR/$litmusout
+then
+	badname=`grep ': Unknown macro ' $LKMM_DESTDIR/$litmusout |
+		sed -e 's/^.*: Unknown macro //' |
+		sed -e 's/ (User error).*$//'`
+	badmsg=' !!! Current LKMM version does not know "'$badname'"'" $litmus"
+	echo $badmsg
+	if ! grep -q '!!!' $LKMM_DESTDIR/$litmusout
+	then
+		echo ' !!! '$badmsg >> $LKMM_DESTDIR/$litmusout 2>&1
+	fi
+	exit 254
+elif grep '^Command exited with non-zero status 124' $LKMM_DESTDIR/$litmusout
+then
+	echo ' !!! Timeout' $litmus
+	if ! grep -q '!!!' $LKMM_DESTDIR/$litmusout
+	then
+		echo ' !!! Timeout' >> $LKMM_DESTDIR/$litmusout 2>&1
+	fi
+	exit 124
 else
 	echo ' !!! Verification error' $litmus
-	if ! grep -q '!!!' $LKMM_DESTDIR/$litmus.out
+	if ! grep -q '!!!' $LKMM_DESTDIR/$litmusout
 	then
-		echo ' !!! Verification error' >> $LKMM_DESTDIR/$litmus.out 2>&1
+		echo ' !!! Verification error' >> $LKMM_DESTDIR/$litmusout 2>&1
 	fi
 	exit 255
 fi
 if test "$outcome" = DEADLOCK
 then
-	if grep '^Observation' $LKMM_DESTDIR/$litmus.out | grep -q 'Never 0 0$'
+	if grep '^Observation' $LKMM_DESTDIR/$litmusout | grep -q 'Never 0 0$'
 	then
 		ret=0
 	else
 		echo " !!! Unexpected non-$outcome verification" $litmus
-		if ! grep -q '!!!' $LKMM_DESTDIR/$litmus.out
+		if ! grep -q '!!!' $LKMM_DESTDIR/$litmusout
 		then
-			echo " !!! Unexpected non-$outcome verification" >> $LKMM_DESTDIR/$litmus.out 2>&1
+			echo " !!! Unexpected non-$outcome verification" >> $LKMM_DESTDIR/$litmusout 2>&1
 		fi
 		ret=1
 	fi
-elif grep '^Observation' $LKMM_DESTDIR/$litmus.out | grep -q $outcome || test "$outcome" = Maybe
+elif grep '^Observation' $LKMM_DESTDIR/$litmusout | grep -q 'Never 0 0$'
+then
+	echo " !!! Unexpected non-$outcome deadlock" $litmus
+	if ! grep -q '!!!' $LKMM_DESTDIR/$litmusout
+	then
+		echo " !!! Unexpected non-$outcome deadlock" $litmus >> $LKMM_DESTDIR/$litmusout 2>&1
+	fi
+	ret=1
+elif grep '^Observation' $LKMM_DESTDIR/$litmusout | grep -q $outcome || test "$outcome" = Maybe
 then
 	ret=0
 else
-	echo " !!! Unexpected non-$outcome verification" $litmus
-	if ! grep -q '!!!' $LKMM_DESTDIR/$litmus.out
+	if test \( -n "$LKMM_HW_MAP_FILE" -a "$outcome" = Sometimes \) -o -n "$datarace_modeled"
 	then
-		echo " !!! Unexpected non-$outcome verification" >> $LKMM_DESTDIR/$litmus.out 2>&1
+		flag="--- Forgiven"
+		ret=0
+	else
+		flag="!!! Unexpected"
+		ret=1
+	fi
+	echo " $flag non-$outcome verification" $litmus
+	if ! grep -qe "$flag" $LKMM_DESTDIR/$litmusout
+	then
+		echo " $flag non-$outcome verification" >> $LKMM_DESTDIR/$litmusout 2>&1
 	fi
-	ret=1
 fi
-tail -2 $LKMM_DESTDIR/$litmus.out | head -1
+tail -2 $LKMM_DESTDIR/$litmusout | head -1
 exit $ret
diff --git a/tools/memory-model/scripts/newlitmushist.sh b/tools/memory-model/scripts/newlitmushist.sh
index 991f8f814881..25235e2049cf 100755
--- a/tools/memory-model/scripts/newlitmushist.sh
+++ b/tools/memory-model/scripts/newlitmushist.sh
@@ -12,7 +12,7 @@
 #
 # Copyright IBM Corporation, 2018
 #
-# Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+# Author: Paul E. McKenney <paulmck@linux.ibm.com>
 
 . scripts/parseargs.sh
 
@@ -43,7 +43,7 @@ fi
 
 # Form full list of litmus tests with no more than the specified
 # number of processes (per the --procs argument).
-find litmus -name '*.litmus' -exec grep -l -m 1 "^C " {} \; > $T/list-C-all
+find litmus -name '*.litmus' -print | mselect7 -arch C > $T/list-C-all
 xargs < $T/list-C-all -r grep -L "^P${LKMM_PROCS}" > $T/list-C-short
 
 # Form list of new tests.  Note: This does not handle litmus-test deletion!
diff --git a/tools/memory-model/scripts/parseargs.sh b/tools/memory-model/scripts/parseargs.sh
index 40f52080fdbd..08ded5909860 100755
--- a/tools/memory-model/scripts/parseargs.sh
+++ b/tools/memory-model/scripts/parseargs.sh
@@ -1,7 +1,7 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0+
 #
-# the corresponding .litmus.out file, and does not judge the result.
+# Parse arguments common to the various scripts.
 #
 # . scripts/parseargs.sh
 #
@@ -9,7 +9,7 @@
 #
 # Copyright IBM Corporation, 2018
 #
-# Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+# Author: Paul E. McKenney <paulmck@linux.ibm.com>
 
 T=/tmp/parseargs.sh.$$
 mkdir $T
@@ -27,6 +27,7 @@ initparam () {
 
 initparam LKMM_DESTDIR "."
 initparam LKMM_HERD_OPTIONS "-conf linux-kernel.cfg"
+initparam LKMM_HW_MAP_FILE ""
 initparam LKMM_JOBS `getconf _NPROCESSORS_ONLN`
 initparam LKMM_PROCS "3"
 initparam LKMM_TIMEOUT "1m"
@@ -37,10 +38,11 @@ usagehelp () {
 	echo "Usage $scriptname [ arguments ]"
 	echo "      --destdir path (place for .litmus.out, default by .litmus)"
 	echo "      --herdopts -conf linux-kernel.cfg ..."
+	echo "      --hw AArch64"
 	echo "      --jobs N (number of jobs, default one per CPU)"
 	echo "      --procs N (litmus tests with at most this many processes)"
 	echo "      --timeout N (herd7 timeout (e.g., 10s, 1m, 2hr, 1d, '')"
-	echo "Defaults: --destdir '$LKMM_DESTDIR_DEF' --herdopts '$LKMM_HERD_OPTIONS_DEF' --jobs '$LKMM_JOBS_DEF' --procs '$LKMM_PROCS_DEF' --timeout '$LKMM_TIMEOUT_DEF'"
+	echo "Defaults: --destdir '$LKMM_DESTDIR_DEF' --herdopts '$LKMM_HERD_OPTIONS_DEF' --hw '$LKMM_HW_MAP_FILE' --jobs '$LKMM_JOBS_DEF' --procs '$LKMM_PROCS_DEF' --timeout '$LKMM_TIMEOUT_DEF'"
 	exit 1
 }
 
@@ -81,7 +83,7 @@ do
 			echo "Cannot create directory --destdir '$LKMM_DESTDIR'"
 			usage
 		fi
-		if test -d "$LKMM_DESTDIR" -a -w "$LKMM_DESTDIR" -a -x "$LKMM_DESTDIR"
+		if test -d "$LKMM_DESTDIR" -a -x "$LKMM_DESTDIR"
 		then
 			:
 		else
@@ -95,6 +97,11 @@ do
 		LKMM_HERD_OPTIONS="$2"
 		shift
 		;;
+	--hw)
+		checkarg --hw "(.map file architecture name)" "$#" "$2" '^[A-Za-z0-9_-]\+' '^--'
+		LKMM_HW_MAP_FILE="$2"
+		shift
+		;;
 	-j[1-9]*)
 		njobs="`echo $1 | sed -e 's/^-j//'`"
 		trailchars="`echo $njobs | sed -e 's/[0-9]\+\(.*\)$/\1/'`"
@@ -106,7 +113,7 @@ do
 		LKMM_JOBS="`echo $njobs | sed -e 's/^\([0-9]\+\).*$/\1/'`"
 		;;
 	--jobs|--job|-j)
-		checkarg --jobs "(number)" "$#" "$2" '^[1-9][0-9]\+$' '^--'
+		checkarg --jobs "(number)" "$#" "$2" '^[1-9][0-9]*$' '^--'
 		LKMM_JOBS="$2"
 		shift
 		;;
@@ -120,6 +127,10 @@ do
 		LKMM_TIMEOUT="$2"
 		shift
 		;;
+	--)
+		shift
+		break
+		;;
 	*)
 		echo Unknown argument $1
 		usage
diff --git a/tools/memory-model/scripts/runlitmus.sh b/tools/memory-model/scripts/runlitmus.sh
new file mode 100755
index 000000000000..94608d4b6502
--- /dev/null
+++ b/tools/memory-model/scripts/runlitmus.sh
@@ -0,0 +1,80 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Without the -hw argument, runs a herd7 test and outputs verification
+# results to a file whose name is that of the specified litmus test,
+# but with ".out" appended.
+#
+# If the --hw argument is specified, this script translates the .litmus
+# C-language file to the specified type of assembly and verifies that.
+# But in this case, litmus tests using complex synchronization (such as
+# locking, RCU, and SRCU) are cheerfully ignored.
+#
+# Either way, return the status of the herd7 command.
+#
+# Usage:
+#	runlitmus.sh file.litmus
+#
+# Run this in the directory containing the memory model, specifying the
+# pathname of the litmus test to check.  The caller is expected to have
+# properly set up the LKMM environment variables.
+#
+# Copyright IBM Corporation, 2019
+#
+# Author: Paul E. McKenney <paulmck@linux.ibm.com>
+
+litmus=$1
+if test -f "$litmus" -a -r "$litmus"
+then
+	:
+else
+	echo ' !!! ' error: \"$litmus\" is not a readable file
+	exit 255
+fi
+
+if test -z "$LKMM_HW_MAP_FILE" -o ! -e $LKMM_DESTDIR/$litmus.out
+then
+	# LKMM run
+	herdoptions=${LKMM_HERD_OPTIONS--conf linux-kernel.cfg}
+	echo Herd options: $herdoptions > $LKMM_DESTDIR/$litmus.out
+	/usr/bin/time $LKMM_TIMEOUT_CMD herd7 $herdoptions $litmus >> $LKMM_DESTDIR/$litmus.out 2>&1
+	ret=$?
+	if test -z "$LKMM_HW_MAP_FILE"
+	then
+		exit $ret
+	fi
+	echo " --- " Automatically generated LKMM output for '"'--hw $LKMM_HW_MAP_FILE'"' run
+fi
+
+# Hardware run
+
+T=/tmp/checklitmushw.sh.$$
+trap 'rm -rf $T' 0 2
+mkdir $T
+
+# Generate filenames
+mapfile="Linux2${LKMM_HW_MAP_FILE}.map"
+themefile="$T/${LKMM_HW_MAP_FILE}.theme"
+herdoptions="-model $LKMM_HW_CAT_FILE"
+hwlitmus=`echo $litmus | sed -e 's/\.litmus$/.litmus.'${LKMM_HW_MAP_FILE}'/'`
+hwlitmusfile=`echo $hwlitmus | sed -e 's,^.*/,,'`
+
+# Don't run on litmus tests with complex synchronization
+if ! scripts/simpletest.sh $litmus
+then
+	echo ' --- ' error: \"$litmus\" contains locking, RCU, or SRCU
+	exit 254
+fi
+
+# Generate the assembly code and run herd7 on it.
+gen_theme7 -n 10 -map $mapfile -call Linux.call > $themefile
+jingle7 -v -theme $themefile $litmus > $LKMM_DESTDIR/$hwlitmus 2> $T/$hwlitmusfile.jingle7.out
+if grep -q "Generated 0 tests" $T/$hwlitmusfile.jingle7.out
+then
+	echo ' !!! ' jingle7 failed, errors in $hwlitmus.err
+	cp $T/$hwlitmusfile.jingle7.out $LKMM_DESTDIR/$hwlitmus.err
+	exit 253
+fi
+/usr/bin/time $LKMM_TIMEOUT_CMD herd7 -unroll 0 $LKMM_DESTDIR/$hwlitmus > $LKMM_DESTDIR/$hwlitmus.out 2>&1
+
+exit $?
diff --git a/tools/memory-model/scripts/runlitmushist.sh b/tools/memory-model/scripts/runlitmushist.sh
index 6ed376f495bb..c6c2bdc67a50 100755
--- a/tools/memory-model/scripts/runlitmushist.sh
+++ b/tools/memory-model/scripts/runlitmushist.sh
@@ -13,7 +13,9 @@
 #
 # Copyright IBM Corporation, 2018
 #
-# Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+# Author: Paul E. McKenney <paulmck@linux.ibm.com>
+
+. scripts/hwfnseg.sh
 
 T=/tmp/runlitmushist.sh.$$
 trap 'rm -rf $T' 0
@@ -30,15 +32,12 @@ fi
 # Prefixes for per-CPU scripts
 for ((i=0;i<$LKMM_JOBS;i++))
 do
-	echo dir="$LKMM_DESTDIR" > $T/$i.sh
 	echo T=$T >> $T/$i.sh
-	echo herdoptions=\"$LKMM_HERD_OPTIONS\" >> $T/$i.sh
 	cat << '___EOF___' >> $T/$i.sh
 	runtest () {
-		echo ' ... ' /usr/bin/time $LKMM_TIMEOUT_CMD herd7 $herdoptions $1 '>' $dir/$1.out '2>&1'
-		if /usr/bin/time $LKMM_TIMEOUT_CMD herd7 $herdoptions $1 > $dir/$1.out 2>&1
+		if scripts/runlitmus.sh $1
 		then
-			if ! grep -q '^Observation ' $dir/$1.out
+			if ! grep -q '^Observation ' $LKMM_DESTDIR/$1$2.out
 			then
 				echo ' !!! Herd failed, no Observation:' $1
 			fi
@@ -47,10 +46,16 @@ do
 			if test "$exitcode" -eq 124
 			then
 				exitmsg="timed out"
+			elif test "$exitcode" -eq 253
+			then
+				exitmsg=
 			else
 				exitmsg="failed, exit code $exitcode"
 			fi
-			echo ' !!! Herd' ${exitmsg}: $1
+			if test -n "$exitmsg"
+			then
+				echo ' !!! Herd' ${exitmsg}: $1
+			fi
 		fi
 	}
 ___EOF___
@@ -59,11 +64,13 @@ done
 awk -v q="'" -v b='\\' '
 {
 	print "echo `grep " q "^P[0-9]" b "+(" q " " $0 " | tail -1 | sed -e " q "s/^P" b "([0-9]" b "+" b ")(.*$/" b "1/" q "` " $0
-}' | bash |
-sort -k1n |
-awk -v ncpu=$LKMM_JOBS -v t=$T '
+}' | sh | sort -k1n |
+awk -v dq='"' -v hwfnseg="$hwfnseg" -v ncpu="$LKMM_JOBS" -v t="$T" '
 {
-	print "runtest " $2 >> t "/" NR % ncpu ".sh";
+	print "if test -z " dq hwfnseg dq " || scripts/simpletest.sh " dq $2 dq
+	print "then"
+	print "\techo runtest " dq $2 dq " " hwfnseg " >> " t "/" NR % ncpu ".sh";
+	print "fi"
 }
 
 END {
diff --git a/tools/memory-model/scripts/simpletest.sh b/tools/memory-model/scripts/simpletest.sh
new file mode 100755
index 000000000000..7edc5d361665
--- /dev/null
+++ b/tools/memory-model/scripts/simpletest.sh
@@ -0,0 +1,35 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Give zero status if this is a simple test and non-zero otherwise.
+# Simple tests do not contain locking, RCU, or SRCU.
+#
+# Usage:
+#	simpletest.sh file.litmus
+#
+# Copyright IBM Corporation, 2019
+#
+# Author: Paul E. McKenney <paulmck@linux.ibm.com>
+
+
+litmus=$1
+
+if test -f "$litmus" -a -r "$litmus"
+then
+	:
+else
+	echo ' --- ' error: \"$litmus\" is not a readable file
+	exit 255
+fi
+exclude="^[[:space:]]*\("
+exclude="${exclude}spin_lock(\|spin_unlock(\|spin_trylock(\|spin_is_locked("
+exclude="${exclude}\|rcu_read_lock(\|rcu_read_unlock("
+exclude="${exclude}\|synchronize_rcu(\|synchronize_rcu_expedited("
+exclude="${exclude}\|srcu_read_lock(\|srcu_read_unlock("
+exclude="${exclude}\|synchronize_srcu(\|synchronize_srcu_expedited("
+exclude="${exclude}\)"
+if grep -q $exclude $litmus
+then
+	exit 255
+fi
+exit 0
diff --git a/tools/testing/selftests/nolibc/.gitignore b/tools/testing/selftests/nolibc/.gitignore
new file mode 100644
index 000000000000..4696df589d68
--- /dev/null
+++ b/tools/testing/selftests/nolibc/.gitignore
@@ -0,0 +1,4 @@
+/initramfs/
+/nolibc-test
+/run.out
+/sysroot/
diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
new file mode 100644
index 000000000000..69ea659caca9
--- /dev/null
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -0,0 +1,135 @@
+# SPDX-License-Identifier: GPL-2.0
+# Makefile for nolibc tests
+include ../../../scripts/Makefile.include
+
+# we're in ".../tools/testing/selftests/nolibc"
+ifeq ($(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
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
new file mode 100644
index 000000000000..78bced95ac63
--- /dev/null
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -0,0 +1,757 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+
+/* platform-specific include files coming from the compiler */
+#include <limits.h>
+
+/* libc-specific include files
+ * The program may be built in 3 ways:
+ *   $(CC) -nostdlib -include /path/to/nolibc.h => NOLIBC already defined
+ *   $(CC) -nostdlib -I/path/to/nolibc/sysroot  => _NOLIBC_* guards are present
+ *   $(CC) with default libc                    => NOLIBC* never defined
+ */
+#ifndef NOLIBC
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifndef _NOLIBC_STDIO_H
+/* standard libcs need more includes */
+#include <linux/reboot.h>
+#include <sys/io.h>
+#include <sys/ioctl.h>
+#include <sys/mount.h>
+#include <sys/reboot.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/sysmacros.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <unistd.h>
+#endif
+#endif
+
+/* will be used by nolibc by getenv() */
+char **environ;
+
+/* definition of a series of tests */
+struct test {
+	const char *name;              // test name
+	int (*func)(int min, int max); // handler
+};
+
+#ifndef _NOLIBC_STDLIB_H
+char *itoa(int i)
+{
+	static char buf[12];
+	int ret;
+
+	ret = snprintf(buf, sizeof(buf), "%d", i);
+	return (ret >= 0 && ret < sizeof(buf)) ? buf : "#err";
+}
+#endif
+
+#define CASE_ERR(err) \
+	case err: return #err
+
+/* returns the error name (e.g. "ENOENT") for common errors, "SUCCESS" for 0,
+ * or the decimal value for less common ones.
+ */
+const char *errorname(int err)
+{
+	switch (err) {
+	case 0: return "SUCCESS";
+	CASE_ERR(EPERM);
+	CASE_ERR(ENOENT);
+	CASE_ERR(ESRCH);
+	CASE_ERR(EINTR);
+	CASE_ERR(EIO);
+	CASE_ERR(ENXIO);
+	CASE_ERR(E2BIG);
+	CASE_ERR(ENOEXEC);
+	CASE_ERR(EBADF);
+	CASE_ERR(ECHILD);
+	CASE_ERR(EAGAIN);
+	CASE_ERR(ENOMEM);
+	CASE_ERR(EACCES);
+	CASE_ERR(EFAULT);
+	CASE_ERR(ENOTBLK);
+	CASE_ERR(EBUSY);
+	CASE_ERR(EEXIST);
+	CASE_ERR(EXDEV);
+	CASE_ERR(ENODEV);
+	CASE_ERR(ENOTDIR);
+	CASE_ERR(EISDIR);
+	CASE_ERR(EINVAL);
+	CASE_ERR(ENFILE);
+	CASE_ERR(EMFILE);
+	CASE_ERR(ENOTTY);
+	CASE_ERR(ETXTBSY);
+	CASE_ERR(EFBIG);
+	CASE_ERR(ENOSPC);
+	CASE_ERR(ESPIPE);
+	CASE_ERR(EROFS);
+	CASE_ERR(EMLINK);
+	CASE_ERR(EPIPE);
+	CASE_ERR(EDOM);
+	CASE_ERR(ERANGE);
+	CASE_ERR(ENOSYS);
+	default:
+		return itoa(err);
+	}
+}
+
+static int pad_spc(int llen, int cnt, const char *fmt, ...)
+{
+	va_list args;
+	int len;
+	int ret;
+
+	for (len = 0; len < cnt - llen; len++)
+		putchar(' ');
+
+	va_start(args, fmt);
+	ret = vfprintf(stdout, fmt, args);
+	va_end(args);
+	return ret < 0 ? ret : ret + len;
+}
+
+/* The tests below are intended to be used by the macroes, which evaluate
+ * expression <expr>, print the status to stdout, and update the "ret"
+ * variable to count failures. The functions themselves return the number
+ * of failures, thus either 0 or 1.
+ */
+
+#define EXPECT_ZR(cond, expr)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_zr(expr, llen); } while (0)
+
+static int expect_zr(int expr, int llen)
+{
+	int ret = !(expr == 0);
+
+	llen += printf(" = %d ", expr);
+	pad_spc(llen, 40, ret ? "[FAIL]\n" : " [OK]\n");
+	return ret;
+}
+
+
+#define EXPECT_NZ(cond, expr, val)			\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_nz(expr, llen; } while (0)
+
+static int expect_nz(int expr, int llen)
+{
+	int ret = !(expr != 0);
+
+	llen += printf(" = %d ", expr);
+	pad_spc(llen, 40, ret ? "[FAIL]\n" : " [OK]\n");
+	return ret;
+}
+
+
+#define EXPECT_EQ(cond, expr, val)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_eq(expr, llen, val); } while (0)
+
+static int expect_eq(int expr, int llen, int val)
+{
+	int ret = !(expr == val);
+
+	llen += printf(" = %d ", expr);
+	pad_spc(llen, 40, ret ? "[FAIL]\n" : " [OK]\n");
+	return ret;
+}
+
+
+#define EXPECT_NE(cond, expr, val)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_ne(expr, llen, val); } while (0)
+
+static int expect_ne(int expr, int llen, int val)
+{
+	int ret = !(expr != val);
+
+	llen += printf(" = %d ", expr);
+	pad_spc(llen, 40, ret ? "[FAIL]\n" : " [OK]\n");
+	return ret;
+}
+
+
+#define EXPECT_GE(cond, expr, val)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_ge(expr, llen, val); } while (0)
+
+static int expect_ge(int expr, int llen, int val)
+{
+	int ret = !(expr >= val);
+
+	llen += printf(" = %d ", expr);
+	pad_spc(llen, 40, ret ? "[FAIL]\n" : " [OK]\n");
+	return ret;
+}
+
+
+#define EXPECT_GT(cond, expr, val)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_gt(expr, llen, val); } while (0)
+
+static int expect_gt(int expr, int llen, int val)
+{
+	int ret = !(expr > val);
+
+	llen += printf(" = %d ", expr);
+	pad_spc(llen, 40, ret ? "[FAIL]\n" : " [OK]\n");
+	return ret;
+}
+
+
+#define EXPECT_LE(cond, expr, val)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_le(expr, llen, val); } while (0)
+
+static int expect_le(int expr, int llen, int val)
+{
+	int ret = !(expr <= val);
+
+	llen += printf(" = %d ", expr);
+	pad_spc(llen, 40, ret ? "[FAIL]\n" : " [OK]\n");
+	return ret;
+}
+
+
+#define EXPECT_LT(cond, expr, val)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_lt(expr, llen, val); } while (0)
+
+static int expect_lt(int expr, int llen, int val)
+{
+	int ret = !(expr < val);
+
+	llen += printf(" = %d ", expr);
+	pad_spc(llen, 40, ret ? "[FAIL]\n" : " [OK]\n");
+	return ret;
+}
+
+
+#define EXPECT_SYSZR(cond, expr)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_syszr(expr, llen); } while (0)
+
+static int expect_syszr(int expr, int llen)
+{
+	int ret = 0;
+
+	if (expr) {
+		ret = 1;
+		llen += printf(" = %d %s ", expr, errorname(errno));
+		llen += pad_spc(llen, 40, "[FAIL]\n");
+	} else {
+		llen += printf(" = %d ", expr);
+		llen += pad_spc(llen, 40, " [OK]\n");
+	}
+	return ret;
+}
+
+
+#define EXPECT_SYSEQ(cond, expr, val)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_syseq(expr, llen, val); } while (0)
+
+static int expect_syseq(int expr, int llen, int val)
+{
+	int ret = 0;
+
+	if (expr != val) {
+		ret = 1;
+		llen += printf(" = %d %s ", expr, errorname(errno));
+		llen += pad_spc(llen, 40, "[FAIL]\n");
+	} else {
+		llen += printf(" = %d ", expr);
+		llen += pad_spc(llen, 40, " [OK]\n");
+	}
+	return ret;
+}
+
+
+#define EXPECT_SYSNE(cond, expr, val)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_sysne(expr, llen, val); } while (0)
+
+static int expect_sysne(int expr, int llen, int val)
+{
+	int ret = 0;
+
+	if (expr == val) {
+		ret = 1;
+		llen += printf(" = %d %s ", expr, errorname(errno));
+		llen += pad_spc(llen, 40, "[FAIL]\n");
+	} else {
+		llen += printf(" = %d ", expr);
+		llen += pad_spc(llen, 40, " [OK]\n");
+	}
+	return ret;
+}
+
+
+#define EXPECT_SYSER(cond, expr, expret, experr)			\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_syserr(expr, expret, experr, llen); } while (0)
+
+static int expect_syserr(int expr, int expret, int experr, int llen)
+{
+	int ret = 0;
+	int _errno = errno;
+
+	llen += printf(" = %d %s ", expr, errorname(_errno));
+	if (expr != expret || _errno != experr) {
+		ret = 1;
+		llen += printf(" != (%d %s) ", expret, errorname(experr));
+		llen += pad_spc(llen, 40, "[FAIL]\n");
+	} else {
+		llen += pad_spc(llen, 40, " [OK]\n");
+	}
+	return ret;
+}
+
+
+#define EXPECT_PTRZR(cond, expr)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_ptrzr(expr, llen); } while (0)
+
+static int expect_ptrzr(const void *expr, int llen)
+{
+	int ret = 0;
+
+	llen += printf(" = <%p> ", expr);
+	if (expr) {
+		ret = 1;
+		llen += pad_spc(llen, 40, "[FAIL]\n");
+	} else {
+		llen += pad_spc(llen, 40, " [OK]\n");
+	}
+	return ret;
+}
+
+
+#define EXPECT_PTRNZ(cond, expr)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_ptrnz(expr, llen); } while (0)
+
+static int expect_ptrnz(const void *expr, int llen)
+{
+	int ret = 0;
+
+	llen += printf(" = <%p> ", expr);
+	if (!expr) {
+		ret = 1;
+		llen += pad_spc(llen, 40, "[FAIL]\n");
+	} else {
+		llen += pad_spc(llen, 40, " [OK]\n");
+	}
+	return ret;
+}
+
+
+#define EXPECT_STRZR(cond, expr)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_strzr(expr, llen); } while (0)
+
+static int expect_strzr(const char *expr, int llen)
+{
+	int ret = 0;
+
+	llen += printf(" = <%s> ", expr);
+	if (expr) {
+		ret = 1;
+		llen += pad_spc(llen, 40, "[FAIL]\n");
+	} else {
+		llen += pad_spc(llen, 40, " [OK]\n");
+	}
+	return ret;
+}
+
+
+#define EXPECT_STRNZ(cond, expr)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_strnz(expr, llen); } while (0)
+
+static int expect_strnz(const char *expr, int llen)
+{
+	int ret = 0;
+
+	llen += printf(" = <%s> ", expr);
+	if (!expr) {
+		ret = 1;
+		llen += pad_spc(llen, 40, "[FAIL]\n");
+	} else {
+		llen += pad_spc(llen, 40, " [OK]\n");
+	}
+	return ret;
+}
+
+
+#define EXPECT_STREQ(cond, expr, cmp)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_streq(expr, llen, cmp); } while (0)
+
+static int expect_streq(const char *expr, int llen, const char *cmp)
+{
+	int ret = 0;
+
+	llen += printf(" = <%s> ", expr);
+	if (strcmp(expr, cmp) != 0) {
+		ret = 1;
+		llen += pad_spc(llen, 40, "[FAIL]\n");
+	} else {
+		llen += pad_spc(llen, 40, " [OK]\n");
+	}
+	return ret;
+}
+
+
+#define EXPECT_STRNE(cond, expr, cmp)				\
+	do { if (!cond) pad_spc(llen, 40, "[SKIPPED]\n"); else ret += expect_strne(expr, llen, cmp); } while (0)
+
+static int expect_strne(const char *expr, int llen, const char *cmp)
+{
+	int ret = 0;
+
+	llen += printf(" = <%s> ", expr);
+	if (strcmp(expr, cmp) == 0) {
+		ret = 1;
+		llen += pad_spc(llen, 40, "[FAIL]\n");
+	} else {
+		llen += pad_spc(llen, 40, " [OK]\n");
+	}
+	return ret;
+}
+
+
+/* declare tests based on line numbers. There must be exactly one test per line. */
+#define CASE_TEST(name) \
+	case __LINE__: llen += printf("%d %s", test, #name);
+
+
+/* used by some syscall tests below */
+int test_getdents64(const char *dir)
+{
+	char buffer[4096];
+	int fd, ret;
+	int err;
+
+	ret = fd = open(dir, O_RDONLY | O_DIRECTORY, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = getdents64(fd, (void *)buffer, sizeof(buffer));
+	err = errno;
+	close(fd);
+
+	errno = err;
+	return ret;
+}
+
+/* Run syscall tests between IDs <min> and <max>.
+ * Return 0 on success, non-zero on failure.
+ */
+int run_syscall(int min, int max)
+{
+	struct stat stat_buf;
+	int proc;
+	int test;
+	int tmp;
+	int ret = 0;
+	void *p1, *p2;
+
+	/* <proc> indicates whether or not /proc is mounted */
+	proc = stat("/proc", &stat_buf) == 0;
+
+	for (test = min; test >= 0 && test <= max; test++) {
+		int llen = 0; // line length
+
+		/* avoid leaving empty lines below, this will insert holes into
+		 * test numbers.
+		 */
+		switch (test + __LINE__ + 1) {
+		CASE_TEST(getpid);            EXPECT_SYSNE(1, getpid(), -1); break;
+		CASE_TEST(getppid);           EXPECT_SYSNE(1, getppid(), -1); break;
+#ifdef NOLIBC
+		CASE_TEST(gettid);            EXPECT_SYSNE(1, gettid(), -1); break;
+#endif
+		CASE_TEST(getpgid_self);      EXPECT_SYSNE(1, getpgid(0), -1); break;
+		CASE_TEST(getpgid_bad);       EXPECT_SYSER(1, getpgid(-1), -1, ESRCH); break;
+		CASE_TEST(kill_0);            EXPECT_SYSZR(1, kill(getpid(), 0)); break;
+		CASE_TEST(kill_CONT);         EXPECT_SYSZR(1, kill(getpid(), 0)); break;
+		CASE_TEST(kill_BADPID);       EXPECT_SYSER(1, kill(INT_MAX, 0), -1, ESRCH); break;
+		CASE_TEST(sbrk);              if ((p1 = p2 = sbrk(4096)) != (void *)-1) p2 = sbrk(-4096); EXPECT_SYSZR(1, (p2 == (void *)-1) || p2 == p1); break;
+		CASE_TEST(brk);               EXPECT_SYSZR(1, brk(sbrk(0))); break;
+		CASE_TEST(chdir_root);        EXPECT_SYSZR(1, chdir("/")); break;
+		CASE_TEST(chdir_dot);         EXPECT_SYSZR(1, chdir(".")); break;
+		CASE_TEST(chdir_blah);        EXPECT_SYSER(1, chdir("/blah"), -1, ENOENT); break;
+		CASE_TEST(chmod_net);         EXPECT_SYSZR(proc, chmod("/proc/self/net", 0555)); break;
+		CASE_TEST(chmod_self);        EXPECT_SYSER(proc, chmod("/proc/self", 0555), -1, EPERM); break;
+		CASE_TEST(chown_self);        EXPECT_SYSER(proc, chown("/proc/self", 0, 0), -1, EPERM); break;
+		CASE_TEST(chroot_root);       EXPECT_SYSZR(1, chroot("/")); break;
+		CASE_TEST(chroot_blah);       EXPECT_SYSER(1, chroot("/proc/self/blah"), -1, ENOENT); break;
+		CASE_TEST(chroot_exe);        EXPECT_SYSER(proc, chroot("/proc/self/exe"), -1, ENOTDIR); break;
+		CASE_TEST(close_m1);          EXPECT_SYSER(1, close(-1), -1, EBADF); break;
+		CASE_TEST(close_dup);         EXPECT_SYSZR(1, close(dup(0))); break;
+		CASE_TEST(dup_0);             tmp = dup(0);  EXPECT_SYSNE(1, tmp, -1); close(tmp); break;
+		CASE_TEST(dup_m1);            tmp = dup(-1); EXPECT_SYSER(1, tmp, -1, EBADF); if (tmp != -1) close(tmp); break;
+		CASE_TEST(dup2_0);            tmp = dup2(0, 100);  EXPECT_SYSNE(1, tmp, -1); close(tmp); break;
+		CASE_TEST(dup2_m1);           tmp = dup2(-1, 100); EXPECT_SYSER(1, tmp, -1, EBADF); if (tmp != -1) close(tmp); break;
+		CASE_TEST(dup3_0);            tmp = dup3(0, 100, 0);  EXPECT_SYSNE(1, tmp, -1); close(tmp); break;
+		CASE_TEST(dup3_m1);           tmp = dup3(-1, 100, 0); EXPECT_SYSER(1, tmp, -1, EBADF); if (tmp != -1) close(tmp); break;
+		CASE_TEST(execve_root);       EXPECT_SYSER(1, execve("/", (char*[]){ [0] = "/", [1] = NULL }, NULL), -1, EACCES); break;
+		CASE_TEST(getdents64_root);   EXPECT_SYSNE(1, test_getdents64("/"), -1); break;
+		CASE_TEST(getdents64_null);   EXPECT_SYSER(1, test_getdents64("/dev/null"), -1, ENOTDIR); break;
+		CASE_TEST(gettimeofday_null); EXPECT_SYSZR(1, gettimeofday(NULL, NULL)); break;
+#ifdef NOLIBC
+		CASE_TEST(gettimeofday_bad1); EXPECT_SYSER(1, gettimeofday((void *)1, NULL), -1, EFAULT); break;
+		CASE_TEST(gettimeofday_bad2); EXPECT_SYSER(1, gettimeofday(NULL, (void *)1), -1, EFAULT); break;
+		CASE_TEST(gettimeofday_bad2); EXPECT_SYSER(1, gettimeofday(NULL, (void *)1), -1, EFAULT); break;
+#endif
+		CASE_TEST(ioctl_tiocinq);     EXPECT_SYSZR(1, ioctl(0, TIOCINQ, &tmp)); break;
+		CASE_TEST(ioctl_tiocinq);     EXPECT_SYSZR(1, ioctl(0, TIOCINQ, &tmp)); break;
+		CASE_TEST(link_root1);        EXPECT_SYSER(1, link("/", "/"), -1, EEXIST); break;
+		CASE_TEST(link_blah);         EXPECT_SYSER(1, link("/proc/self/blah", "/blah"), -1, ENOENT); break;
+		CASE_TEST(link_dir);          EXPECT_SYSER(1, link("/", "/blah"), -1, EPERM); break;
+		CASE_TEST(link_cross);        EXPECT_SYSER(proc, link("/proc/self/net", "/blah"), -1, EXDEV); break;
+		CASE_TEST(lseek_m1);          EXPECT_SYSER(1, lseek(-1, 0, SEEK_SET), -1, EBADF); break;
+		CASE_TEST(lseek_0);           EXPECT_SYSER(1, lseek(0, 0, SEEK_SET), -1, ESPIPE); break;
+		CASE_TEST(mkdir_root);        EXPECT_SYSER(1, mkdir("/", 0755), -1, EEXIST); break;
+		CASE_TEST(open_tty);          EXPECT_SYSNE(1, tmp = open("/dev/null", 0), -1); if (tmp != -1) close(tmp); break;
+		CASE_TEST(open_blah);         EXPECT_SYSER(1, tmp = open("/proc/self/blah", 0), -1, ENOENT); if (tmp != -1) close(tmp); break;
+		CASE_TEST(poll_null);         EXPECT_SYSZR(1, poll(NULL, 0, 0)); break;
+		CASE_TEST(poll_stdout);       EXPECT_SYSNE(1, ({ struct pollfd fds = { 1, POLLOUT, 0}; poll(&fds, 1, 0); }), -1); break;
+		CASE_TEST(poll_fault);        EXPECT_SYSER(1, poll((void *)1, 1, 0), -1, EFAULT); break;
+		CASE_TEST(read_badf);         EXPECT_SYSER(1, read(-1, &tmp, 1), -1, EBADF); break;
+		CASE_TEST(sched_yield);       EXPECT_SYSZR(1, sched_yield()); break;
+		CASE_TEST(select_null);       EXPECT_SYSZR(1, ({ struct timeval tv = { 0 }; select(0, NULL, NULL, NULL, &tv); })); break;
+		CASE_TEST(select_stdout);     EXPECT_SYSNE(1, ({ fd_set fds; FD_ZERO(&fds); FD_SET(1, &fds); select(2, NULL, &fds, NULL, NULL); }), -1); break;
+		CASE_TEST(select_fault);      EXPECT_SYSER(1, select(1, (void *)1, NULL, NULL, 0), -1, EFAULT); break;
+		CASE_TEST(stat_blah);         EXPECT_SYSER(1, stat("/proc/self/blah", &stat_buf), -1, ENOENT); break;
+		CASE_TEST(stat_fault);        EXPECT_SYSER(1, stat(NULL, &stat_buf), -1, EFAULT); break;
+		CASE_TEST(symlink_root);      EXPECT_SYSER(1, symlink("/", "/"), -1, EEXIST); break;
+		CASE_TEST(unlink_root);       EXPECT_SYSER(1, unlink("/"), -1, EISDIR); break;
+		CASE_TEST(unlink_blah);       EXPECT_SYSER(1, unlink("/proc/self/blah"), -1, ENOENT); break;
+		CASE_TEST(wait_child);        EXPECT_SYSER(1, wait(&tmp), -1, ECHILD); break;
+		CASE_TEST(waitpid_min);       EXPECT_SYSER(1, waitpid(INT_MIN, &tmp, WNOHANG), -1, ESRCH); break;
+		CASE_TEST(waitpid_child);     EXPECT_SYSER(1, waitpid(getpid(), &tmp, WNOHANG), -1, ECHILD); break;
+		CASE_TEST(write_badf);        EXPECT_SYSER(1, write(-1, &tmp, 1), -1, EBADF); break;
+		CASE_TEST(write_zero);        EXPECT_SYSZR(1, write(1, &tmp, 0)); break;
+		case __LINE__:
+			return ret; /* must be last */
+		/* note: do not set any defaults so as to permit holes above */
+		}
+	}
+	return ret;
+}
+
+int run_stdlib(int min, int max)
+{
+	int test;
+	int tmp;
+	int ret = 0;
+	void *p1, *p2;
+
+	for (test = min; test >= 0 && test <= max; test++) {
+		int llen = 0; // line length
+
+		/* avoid leaving empty lines below, this will insert holes into
+		 * test numbers.
+		 */
+		switch (test + __LINE__ + 1) {
+		CASE_TEST(getenv_TERM);        EXPECT_STRNZ(1, getenv("TERM")); break;
+		CASE_TEST(getenv_blah);        EXPECT_STRZR(1, getenv("blah")); break;
+		CASE_TEST(setcmp_blah_blah);   EXPECT_EQ(1, strcmp("blah", "blah"), 0); break;
+		CASE_TEST(setcmp_blah_blah2);  EXPECT_NE(1, strcmp("blah", "blah2"), 0); break;
+		CASE_TEST(setncmp_blah_blah);  EXPECT_EQ(1, strncmp("blah", "blah", 10), 0); break;
+		CASE_TEST(setncmp_blah_blah4); EXPECT_EQ(1, strncmp("blah", "blah4", 4), 0); break;
+		CASE_TEST(setncmp_blah_blah5); EXPECT_NE(1, strncmp("blah", "blah5", 5), 0); break;
+		CASE_TEST(setncmp_blah_blah6); EXPECT_NE(1, strncmp("blah", "blah6", 6), 0); break;
+		CASE_TEST(strchr_foobar_o);    EXPECT_STREQ(1, strchr("foobar", 'o'), "oobar"); break;
+		CASE_TEST(strchr_foobar_z);    EXPECT_STRZR(1, strchr("foobar", 'z')); break;
+		CASE_TEST(strrchr_foobar_o);   EXPECT_STREQ(1, strrchr("foobar", 'o'), "obar"); break;
+		CASE_TEST(strrchr_foobar_z);   EXPECT_STRZR(1, strrchr("foobar", 'z')); break;
+		case __LINE__:
+			return ret; /* must be last */
+		/* note: do not set any defaults so as to permit holes above */
+		}
+	}
+	return ret;
+}
+
+/* prepare what needs to be prepared for pid 1 (stdio, /dev, /proc, etc) */
+int prepare(void)
+{
+	struct stat stat_buf;
+
+	/* It's possible that /dev doesn't even exist or was not mounted, so
+	 * we'll try to create it, mount it, or create minimal entries into it.
+	 * We want at least /dev/null and /dev/console.
+	 */
+	if (stat("/dev/.", &stat_buf) == 0 || mkdir("/dev", 0755) == 0) {
+		if (stat("/dev/console", &stat_buf) != 0 ||
+		    stat("/dev/null", &stat_buf) != 0) {
+			/* try devtmpfs first, otherwise fall back to manual creation */
+			if (mount("/dev", "/dev", "devtmpfs", 0, 0) != 0) {
+				mknod("/dev/console", 0600 | S_IFCHR, makedev(5, 1));
+				mknod("/dev/null",    0666 | S_IFCHR, makedev(1, 3));
+			}
+		}
+	}
+
+	/* If no /dev/console was found before calling init, stdio is closed so
+	 * we need to reopen it from /dev/console. If it failed above, it will
+	 * still fail here and we cannot emit a message anyway.
+	 */
+	if (close(dup(1)) == -1) {
+		int fd = open("/dev/console", O_RDWR);
+
+		if (fd >= 0) {
+			if (fd != 0)
+				dup2(fd, 0);
+			if (fd != 1)
+				dup2(fd, 1);
+			if (fd != 2)
+				dup2(fd, 2);
+			if (fd > 2)
+				close(fd);
+			puts("\nSuccessfully reopened /dev/console.");
+		}
+	}
+
+	/* try to mount /proc if not mounted. Silently fail otherwise */
+	if (stat("/proc/.", &stat_buf) == 0 || mkdir("/proc", 0755) == 0) {
+		if (stat("/proc/self", &stat_buf) != 0)
+			mount("/proc", "/proc", "proc", 0, 0);
+	}
+
+	return 0;
+}
+
+/* This is the definition of known test names, with their functions */
+static struct test test_names[] = {
+	/* add new tests here */
+	{ .name = "syscall",   .func = run_syscall  },
+	{ .name = "stdlib",    .func = run_stdlib   },
+	{ 0 }
+};
+
+int main(int argc, char **argv, char **envp)
+{
+	int min = 0;
+	int max = __INT_MAX__;
+	int ret = 0;
+	int err;
+	int idx;
+	char *test;
+
+	environ = envp;
+
+	/* when called as init, it's possible that no console was opened, for
+	 * example if no /dev file system was provided. We'll check that fd#1
+	 * was opened, and if not we'll attempt to create and open /dev/console
+	 * and /dev/null that we'll use for later tests.
+	 */
+	if (getpid() == 1)
+		prepare();
+
+	/* the definition of a series of tests comes from either argv[1] or the
+	 * "NOLIBC_TEST" environment variable. It's made of a comma-delimited
+	 * series of test names and optional ranges:
+	 *    syscall:5-15[:.*],stdlib:8-10
+	 */
+	test = argv[1];
+	if (!test)
+		test = getenv("NOLIBC_TEST");
+
+	if (test) {
+		char *comma, *colon, *dash, *value;
+
+		do {
+			comma = strchr(test, ',');
+			if (comma)
+				*(comma++) = '\0';
+
+			colon = strchr(test, ':');
+			if (colon)
+				*(colon++) = '\0';
+
+			for (idx = 0; test_names[idx].name; idx++) {
+				if (strcmp(test, test_names[idx].name) == 0)
+					break;
+			}
+
+			if (test_names[idx].name) {
+				/* The test was named, it will be called at least
+				 * once. We may have an optional range at <colon>
+				 * here, which defaults to the full range.
+				 */
+				do {
+					min = 0; max = __INT_MAX__;
+					value = colon;
+					if (value && *value) {
+						colon = strchr(value, ':');
+						if (colon)
+							*(colon++) = '\0';
+
+						dash = strchr(value, '-');
+						if (dash)
+							*(dash++) = '\0';
+
+						/* support :val: :min-max: :min-: :-max: */
+						if (*value)
+							min = atoi(value);
+						if (!dash)
+							max = min;
+						else if (*dash)
+							max = atoi(dash);
+
+						value = colon;
+					}
+
+					/* now's time to call the test */
+					printf("Running test '%s'\n", test_names[idx].name);
+					err = test_names[idx].func(min, max);
+					ret += err;
+					printf("Errors during this test: %d\n\n", err);
+				} while (colon && *colon);
+			} else
+				printf("Ignoring unknown test name '%s'\n", test);
+
+			test = comma;
+		} while (test && *test);
+	} else {
+		/* no test mentioned, run everything */
+		for (idx = 0; test_names[idx].name; idx++) {
+			printf("Running test '%s'\n", test_names[idx].name);
+			err = test_names[idx].func(min, max);
+			ret += err;
+			printf("Errors during this test: %d\n\n", err);
+		}
+	}
+
+	printf("Total number of errors: %d\n", ret);
+
+	if (getpid() == 1) {
+		/* we're running as init, there's no other process on the
+		 * system, thus likely started from a VM for a quick check.
+		 * Exiting will provoke a kernel panic that may be reported
+		 * as an error by Qemu or the hypervisor, while stopping
+		 * cleanly will often be reported as a success. This allows
+		 * to use the output of this program for bisecting kernels.
+		 */
+		printf("Leaving init with final status: %d\n", !!ret);
+		if (ret == 0)
+			reboot(LINUX_REBOOT_CMD_POWER_OFF);
+#if defined(__x86_64__)
+		/* QEMU started with "-device isa-debug-exit -no-reboot" will
+		 * exit with status code 2N+1 when N is written to 0x501. We
+		 * hard-code the syscall here as it's arch-dependent.
+		 */
+#if defined(_NOLIBC_SYS_H)
+		else if (my_syscall3(__NR_ioperm, 0x501, 1, 1) == 0)
+#else
+		else if (ioperm(0x501, 1, 1) == 0)
+#endif
+			asm volatile ("outb %%al, %%dx" :: "d"(0x501), "a"(0));
+		/* if it does nothing, fall back to the regular panic */
+#endif
+	}
+
+	printf("Exiting with status %d\n", !!ret);
+	return !!ret;
+}
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-check-branches.sh b/tools/testing/selftests/rcutorture/bin/kvm-check-branches.sh
index f17000a2ccf1..ed0ec7f0927e 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-check-branches.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-check-branches.sh
@@ -35,7 +35,7 @@ then
 	exit 1
 fi
 
-# Remember where we started so that we can get back and the end.
+# Remember where we started so that we can get back at the end.
 curcommit="`git status | head -1 | awk '{ print $NF }'`"
 
 nfail=0
@@ -73,15 +73,10 @@ do
 		# Test the specified commit.
 		git checkout $i > $resdir/$ds/$idir/git-checkout.out 2>&1
 		echo git checkout return code: $? "(Commit $ntry: $i)"
-		kvm.sh --allcpus --duration 3 --trust-make > $resdir/$ds/$idir/kvm.sh.out 2>&1
+		kvm.sh --allcpus --duration 3 --trust-make --datestamp "$ds/$idir" > $resdir/$ds/$idir/kvm.sh.out 2>&1
 		ret=$?
 		echo kvm.sh return code $ret for commit $i from branch $gitbr
-
-		# Move the build products to their resting place.
-		runresdir="`grep -m 1 '^Results directory:' < $resdir/$ds/$idir/kvm.sh.out | sed -e 's/^Results directory://'`"
-		mv $runresdir $resdir/$ds/$idir
-		rrd="`echo $runresdir | sed -e 's,^.*/,,'`"
-		echo Run results: $resdir/$ds/$idir/$rrd
+		echo Run results: $resdir/$ds/$idir
 		if test "$ret" -ne 0
 		then
 			# Failure, so leave all evidence intact.
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-remote.sh b/tools/testing/selftests/rcutorture/bin/kvm-remote.sh
index 0ff59bd8b640..9f0a5d5ff2dd 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-remote.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-remote.sh
@@ -262,6 +262,7 @@ echo All batches started. `date` | tee -a "$oldrun/remote-log"
 # Wait for all remaining scenarios to complete and collect results.
 for i in $systems
 do
+	echo " ---" Waiting for $i `date` | tee -a "$oldrun/remote-log"
 	while checkremotefile "$i" "$resdir/$ds/remote.run"
 	do
 		sleep 30
diff --git a/tools/testing/selftests/rcutorture/bin/kvm.sh b/tools/testing/selftests/rcutorture/bin/kvm.sh
index 263e16aeca0e..6c734818a875 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm.sh
@@ -164,7 +164,7 @@ do
 		shift
 		;;
 	--gdb)
-		TORTURE_KCONFIG_GDB_ARG="CONFIG_DEBUG_INFO=y"; export TORTURE_KCONFIG_GDB_ARG
+		TORTURE_KCONFIG_GDB_ARG="CONFIG_DEBUG_INFO_NONE=n CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y"; export TORTURE_KCONFIG_GDB_ARG
 		TORTURE_BOOT_GDB_ARG="nokaslr"; export TORTURE_BOOT_GDB_ARG
 		TORTURE_QEMU_GDB_ARG="-s -S"; export TORTURE_QEMU_GDB_ARG
 		;;
@@ -180,7 +180,7 @@ do
 		shift
 		;;
 	--kasan)
-		TORTURE_KCONFIG_KASAN_ARG="CONFIG_DEBUG_INFO=y CONFIG_KASAN=y"; export TORTURE_KCONFIG_KASAN_ARG
+		TORTURE_KCONFIG_KASAN_ARG="CONFIG_DEBUG_INFO_NONE=n CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y CONFIG_KASAN=y"; export TORTURE_KCONFIG_KASAN_ARG
 		if test -n "$torture_qemu_mem_default"
 		then
 			TORTURE_QEMU_MEM=2G
@@ -192,7 +192,7 @@ do
 		shift
 		;;
 	--kcsan)
-		TORTURE_KCONFIG_KCSAN_ARG="CONFIG_DEBUG_INFO=y CONFIG_KCSAN=y CONFIG_KCSAN_STRICT=y CONFIG_KCSAN_REPORT_ONCE_IN_MS=100000 CONFIG_KCSAN_VERBOSE=y CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y"; export TORTURE_KCONFIG_KCSAN_ARG
+		TORTURE_KCONFIG_KCSAN_ARG="CONFIG_DEBUG_INFO_NONE=n CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y CONFIG_KCSAN=y CONFIG_KCSAN_STRICT=y CONFIG_KCSAN_REPORT_ONCE_IN_MS=100000 CONFIG_KCSAN_VERBOSE=y CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y"; export TORTURE_KCONFIG_KCSAN_ARG
 		;;
 	--kmake-arg|--kmake-args)
 		checkarg --kmake-arg "(kernel make arguments)" $# "$2" '.*' '^error$'