From 8085d0402bf7d72aa0580656133f52da3405b2d0 Mon Sep 17 00:00:00 2001
From: Josh Poimboeuf <jpoimboe@redhat.com>
Date: Mon, 17 Feb 2014 22:37:07 -0600
Subject: [PATCH] build and install core module with make

Build and install the kpatch core module with make and make install,
rather than building it every time with kpatch build.

The only downside to this approach is that the user has to make and make
install kpatch every time they get a new kernel.  But this is only
temporary, until the kpatch module is delivered in an RPM.
---
 .gitignore                |  2 ++
 Makefile.inc              |  1 +
 README.md                 | 22 +++++++++++++++++-----
 kmod/Makefile             |  6 ++++--
 kmod/core/Makefile        | 10 ++++++++--
 kmod/patch/Makefile       |  1 -
 kmod/patch/kpatch.h       |  1 +
 kpatch-build/kpatch-build |  9 ++-------
 8 files changed, 35 insertions(+), 17 deletions(-)
 create mode 120000 kmod/patch/kpatch.h

diff --git a/.gitignore b/.gitignore
index 1b5b1e6..17f662f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,6 +4,8 @@
 *.ko.cmd
 *.mod.c
 *.swp
+.tmp_versions
+Module.symvers
 kpatch-build/add-patches-section
 kpatch-build/create-diff-object
 kpatch-build/link-vmlinux-syms
diff --git a/Makefile.inc b/Makefile.inc
index e32efe9..b26afb7 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -5,6 +5,7 @@ INSTALL = /usr/bin/install
 
 PREFIX    ?= /usr/local
 SBINDIR    = $(DESTDIR)$(PREFIX)/sbin
+MODULESDIR = $(DESTDIR)$(PREFIX)/lib/modules
 LIBEXECDIR = $(DESTDIR)$(PREFIX)/libexec/kpatch
 DATADIR    = $(DESTDIR)$(PREFIX)/share/kpatch
 
diff --git a/README.md b/README.md
index a9e899b..f3d4b4f 100644
--- a/README.md
+++ b/README.md
@@ -26,13 +26,25 @@ Quick Start
 kernel on any distribution, the "kpatch build" command currently
 only works on Fedora.*
 
-First, use diff to make a source patch against the kernel tree, e.g. foo.patch.
-Then:
+Load the kpatch core module:
 
-    kpatch build foo.patch
-    sudo insmod kpatch.ko kpatch-foo.ko
+    sudo insmod /usr/local/lib/modules/$(uname -r)/kpatch/kpatch.ko
 
-Voila, your kernel is patched.
+Make a source patch against the kernel tree:
+
+    # from a kernel git tree:
+    git diff > /path/to/foo.patch
+
+Build the hot patch kernel module:
+
+    kpatch build /path/to/foo.patch
+
+This outputs a hot patch module named `kpatch-foo.ko` in the current
+directory.  Now apply it to the running kernel:
+
+    sudo insmod kpatch-foo.ko
+
+Done!  The kernel is now patched.
 
 
 License
diff --git a/kmod/Makefile b/kmod/Makefile
index 2ff48cc..ead053a 100644
--- a/kmod/Makefile
+++ b/kmod/Makefile
@@ -1,11 +1,13 @@
 include ../Makefile.inc
 
 all:
+	$(MAKE) -C core
 
 install:
-	$(INSTALL) -d $(DATADIR)/core
-	$(INSTALL) -m 644 core/* $(DATADIR)/core
+	$(INSTALL) -d $(MODULESDIR)/(uname -r)/kpatch
+	$(INSTALL) -m 644 core/kpatch.ko $(MODULESDIR)/(uname -r)/kpatch
 	$(INSTALL) -d $(DATADIR)/patch
 	$(INSTALL) -m 644 patch/* $(DATADIR)/patch
 
 clean:
+	$(MAKE) -C core clean
diff --git a/kmod/core/Makefile b/kmod/core/Makefile
index 9a2a411..2510901 100644
--- a/kmod/core/Makefile
+++ b/kmod/core/Makefile
@@ -1,6 +1,12 @@
 # make rules
-KPATCH_BUILD ?= /usr/lib/modules/$(shell uname -r)/build
-KPATCH_MAKE = $(MAKE) -C $(KPATCH_BUILD) M=$(PWD)
+KPATCH_BUILD ?= /usr/src/kernels/$(shell uname -r)
+THISDIR := $(abspath $(dir $(lastword $(MAKEFILE_LIST))))
+
+ifeq ($(wildcard $(KPATCH_BUILD)),)
+$(error $(KPATCH_BUILD) doesn\'t exist.  Try installing the kernel-devel-$(shell uname -r) RPM.)
+endif
+
+KPATCH_MAKE = $(MAKE) -C $(KPATCH_BUILD) M=$(THISDIR)
 
 kpatch.ko: core.c trampoline.S
 	$(KPATCH_MAKE) kpatch.ko
diff --git a/kmod/patch/Makefile b/kmod/patch/Makefile
index d278191..a42a4fb 100644
--- a/kmod/patch/Makefile
+++ b/kmod/patch/Makefile
@@ -1,7 +1,6 @@
 KPATCH_NAME ?= patch
 KPATCH_BUILD ?= /lib/modules/$(shell uname -r)/build
 KPATCH_MAKE = $(MAKE) -C $(KPATCH_BUILD) M=$(PWD)
-ccflags-y += -I$(KPATCH_BASEDIR)
 
 obj-m += kpatch-$(KPATCH_NAME).o
 
diff --git a/kmod/patch/kpatch.h b/kmod/patch/kpatch.h
new file mode 120000
index 0000000..e8de666
--- /dev/null
+++ b/kmod/patch/kpatch.h
@@ -0,0 +1 @@
+../core/kpatch.h
\ No newline at end of file
diff --git a/kpatch-build/kpatch-build b/kpatch-build/kpatch-build
index 976b102..983fc4c 100755
--- a/kpatch-build/kpatch-build
+++ b/kpatch-build/kpatch-build
@@ -153,21 +153,16 @@ for i in $FILES; do
 	"$TOOLSDIR"/create-diff-object "orig/$i" "patched/$i" "output/$i" >> "$LOGFILE" 2>&1 || die
 done
 
-echo "Building core module: kpatch.ko"
-cd core
-KPATCH_BUILD="$KSRCDIR" make >> "$LOGFILE" 2>&1 || die
-cd ..
-
 echo "Building patch module: kpatch-$PATCHNAME.ko"
 cd "$TEMPDIR/output"
 ld -r -o ../patch/output.o $FILES >> "$LOGFILE" 2>&1 || die
 cd "$TEMPDIR/patch"
 "$TOOLSDIR"/add-patches-section output.o ../vmlinux >> "$LOGFILE" 2>&1 || die
-KPATCH_BASEDIR="$TEMPDIR/core" KPATCH_BUILD="$KSRCDIR" KPATCH_NAME="$PATCHNAME" make >> "$LOGFILE" 2>&1 || die
+KPATCH_BUILD="$KSRCDIR" KPATCH_NAME="$PATCHNAME" make >> "$LOGFILE" 2>&1 || die
 "$STRIPCMD" "kpatch-$PATCHNAME.ko" >> "$LOGFILE" 2>&1 || die
 "$TOOLSDIR"/link-vmlinux-syms "kpatch-$PATCHNAME.ko" ../vmlinux >> "$LOGFILE" 2>&1 || die
 
-cp -f "$TEMPDIR/patch/kpatch-$PATCHNAME.ko" "$TEMPDIR/core/kpatch.ko" "$BASE" || die
+cp -f "$TEMPDIR/patch/kpatch-$PATCHNAME.ko" "$BASE" || die
 
 cleanup
 echo "SUCCESS"