perf: Make perf build for x86 with UAPI disintegration applied

Make perf build for x86 once the UAPI disintegration patches for that arch
have been applied by adding the appropriate -I flags - in the right order -
and then converting some #includes that use ../.. notation to find main kernel
headerfiles to use <asm/foo.h> and <linux/foo.h> instead.

Note that -Iarch/foo/include/uapi is present _before_ -Iarch/foo/include.
This makes sure we get the userspace version of the pt_regs struct.  Ideally,
we wouldn't have the latter -I flag at all, but unfortunately we want
asm/svm.h and asm/vmx.h in builtin-kvm.c and these aren't part of the UAPI -
at least not for x86.  I wonder if the bits outside of the __KERNEL__ guards
*should* be transferred there.

I note also that perf seems to do its dependency handling manually by listing
all the header files it might want to use in LIB_H in the Makefile.  Can this
be changed to use -MD?

Note that to do make this work, we need to export and UAPI disintegrate
linux/hw_breakpoint.h, which I think should've been exported previously so that
perf can access the bits.  We have to do this in the same patch to maintain
bisectability.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 28 insertions, 1 deletions

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 00deed4d6159..0a619af5be43 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -169,7 +169,34 @@ endif
 
 ### --- END CONFIGURATION SECTION ---
 
-BASIC_CFLAGS = -Iutil/include -Iarch/$(ARCH)/include -I$(OUTPUT)util -I$(TRACE_EVENT_DIR) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(shell pwd)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+#$(info Determined 'srctree' to be $(srctree))
+endif
+
+ifneq ($(objtree),)
+#$(info Determined 'objtree' to be $(objtree))
+endif
+
+ifneq ($(OUTPUT),)
+#$(info Determined 'OUTPUT' to be $(OUTPUT))
+endif
+
+BASIC_CFLAGS = \
+        -Iutil/include \
+        -Iarch/$(ARCH)/include \
+        $(if $(objtree),-I$(objtree)/arch/$(ARCH)/include/generated/uapi) \
+        -I$(srctree)/arch/$(ARCH)/include/uapi \
+        -I$(srctree)/arch/$(ARCH)/include \
+        $(if $(objtree),-I$(objtree)/include/generated/uapi) \
+        -I$(srctree)/include/uapi \
+        -I$(srctree)/include \
+        -I$(OUTPUT)util \
+        -Iutil \
+        -I. \
+        -I$(TRACE_EVENT_DIR) \
+        -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE
 BASIC_LDFLAGS =
 
 # Guard against environment variables