selftests: new x86 breakpoints selftest

Bring a first selftest in the relevant directory.  This tests several
combinations of breakpoints and watchpoints in x86, as well as icebp traps
and int3 traps.  Given the amount of breakpoint regressions we raised
after we merged the generic breakpoint infrastructure, such selftest
became necessary and can still serve today as a basis for new patches that
touch the do_debug() path.

Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Jason Wessel <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Michal Marek <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

tools/testing/selftests/Makefile

@@ -1,4 +1,4 @@
-TARGETS =
+TARGETS = breakpoints
 
 all:
 	for TARGET in $(TARGETS); do \

tools/testing/selftests/breakpoints/Makefile

@@ -0,0 +1,20 @@
+# Taken from perf makefile
+uname_M := $(shell uname -m 2>/dev/null || echo not)
+ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/i386/)
+ifeq ($(ARCH),i386)
+        ARCH := x86
+endif
+ifeq ($(ARCH),x86_64)
+	ARCH := x86
+endif
+
+
+all:
+ifeq ($(ARCH),x86)
+	gcc breakpoint_test.c -o run_test
+else
+	echo "Not an x86 target, can't build breakpoints selftests"
+endif
+
+clean:
+	rm -fr run_test