Generate a fake EBDA with kexec, removing the need for a custom xen (#…

…227)

This modifies the segment at 0x0 so that it contains enough of a fake
Extended BIOS Data Area at addresses 0x40e and 0x413 that Xen can
correctly locate its trampoline code.

Since custom Xen is no longer required, we can remove the module,
the patches and all of the references to it in the board definition
files.

Makefile

@@ -325,7 +325,6 @@ bin_modules-$(CONFIG_FLASHROM) += flashrom
 bin_modules-$(CONFIG_CRYPTSETUP) += cryptsetup
 bin_modules-$(CONFIG_GPG) += gpg
 bin_modules-$(CONFIG_LVM2) += lvm2
-bin_modules-$(CONFIG_XEN) += xen
 bin_modules-$(CONFIG_DROPBEAR) += dropbear
 bin_modules-$(CONFIG_FLASHTOOLS) += flashtools
 bin_modules-$(CONFIG_NEWT) += newt
@@ -339,8 +338,6 @@ $(foreach m, $(modules-y), \
 	$(call map,initrd_lib_add,$(call libs,$m)) \
 )
 
-#$(foreach _, $(call outputs,xen), $(eval $(call initrd_bin,$_)))
-
 # hack to install busybox into the initrd
 $(build)/$(BOARD)/heads.cpio: busybox.intermediate
 initrd_bins += $(initrd_bin_dir)/busybox

boards/r630.config

@@ -16,7 +16,6 @@ CONFIG_PCIUTILS=y
 CONFIG_POPT=y
 CONFIG_QRENCODE=y
 CONFIG_TPMTOTP=y
-#CONFIG_XEN=y
 CONFIG_DROPBEAR=y
 
 CONFIG_LINUX_USB=y

boards/s2600wf.config

@@ -24,7 +24,6 @@ CONFIG_PCIUTILS=y
 #CONFIG_POPT=y
 #CONFIG_QRENCODE=y
 #CONFIG_TPMTOTP=y
-#CONFIG_XEN=y
 CONFIG_DROPBEAR=y
 
 CONFIG_LINUX_USB=y

boards/winterfell.config

@@ -26,7 +26,6 @@ CONFIG_PCIUTILS=y
 CONFIG_POPT=y
 #CONFIG_QRENCODE=y
 #CONFIG_TPMTOTP=y
-CONFIG_XEN=y
 CONFIG_DROPBEAR=y
 endif
 

boards/x220.config

@@ -15,8 +15,6 @@ CONFIG_PCIUTILS=y
 CONFIG_POPT=y
 CONFIG_QRENCODE=y
 CONFIG_TPMTOTP=y
-CONFIG_XEN=y
-CONFIG_XEN_VERSION=4.6
 CONFIG_DROPBEAR=y
 
 CONFIG_LINUX_USB=y

boards/x230.config

@@ -14,8 +14,6 @@ CONFIG_PCIUTILS=y
 CONFIG_POPT=y
 CONFIG_QRENCODE=y
 CONFIG_TPMTOTP=y
-CONFIG_XEN=y
-CONFIG_XEN_VERSION=4.8
 CONFIG_DROPBEAR=y
 
 CONFIG_LINUX_USB=y

modules/kexec

@@ -1,10 +1,10 @@
 modules-$(CONFIG_KEXEC) += kexec
 
-kexec_version := 2.0.12
+kexec_version := 2.0.16
 kexec_dir := kexec-tools-$(kexec_version)
 kexec_tar := kexec-tools-$(kexec_version).tar.gz
 kexec_url := https://kernel.org/pub/linux/utils/kernel/kexec/$(kexec_tar)
-kexec_hash := cc7b60dad0da202004048a6179d8a53606943062dd627a2edba45a8ea3a85135
+kexec_hash := cf17fc99bf77c9b39f06ee88ac0e86d0349c4a0c3f8214a3cc78eece872f6f3a
 
 kexec_configure := ./configure \
 	$(CROSS_TOOLS) \

patches/kexec-2.0.16.patch

@@ -0,0 +1,89 @@
+diff -u --recursive clean/kexec-tools-2.0.16/Makefile.in kexec-tools-2.0.16/Makefile.in
+--- clean/kexec-tools-2.0.16/Makefile.in	2016-12-09 04:42:06.000000000 -0500
++++ kexec-tools-2.0.16/Makefile.in	2018-02-28 05:39:20.461000000 -0500
+@@ -158,16 +158,16 @@
+
+ # kdump (read a crashdump from memory)
+ #
+-include $(srcdir)/kdump/Makefile
++#include $(srcdir)/kdump/Makefile
+
+ # vmcore-dmesg (read dmesg from a vmcore)
+ #
+-include $(srcdir)/vmcore-dmesg/Makefile
++#include $(srcdir)/vmcore-dmesg/Makefile
+
+ #
+ # kexec_test (test program)
+ #
+-include $(srcdir)/kexec_test/Makefile
++#include $(srcdir)/kexec_test/Makefile
+
+ SPEC=$(PACKAGE_NAME).spec
+ GENERATED_SRCS:= $(SPEC)
+diff -u --recursive clean/kexec-tools-2.0.16/include/config.h kexec-tools-2.0.16/include/config.h
+--- clean/kexec-tools-2.0.16/include/config.h	2017-11-20 04:17:12.000000000 -0500
++++ kexec-tools-2.0.16/include/config.h	2018-02-28 05:39:22.420000000 -0500
+@@ -17,7 +17,7 @@
+ /* #undef HAVE_LIBXENCTRL */
+
+ /* Define to 1 if you have the `z' library (-lz). */
+-/* #undef HAVE_LIBZ */
++#define HAVE_LIBZ 1
+
+ /* Define to 1 if you have the <memory.h> header file. */
+ #define HAVE_MEMORY_H 1
+diff -u --recursive clean/kexec-tools-2.0.16/kexec/kexec.c kexec-tools-2.0.16/kexec/kexec.c
+--- clean/kexec-tools-2.0.16/kexec/kexec.c	2017-03-02 04:45:46.000000000 -0500
++++ kexec-tools-2.0.16/kexec/kexec.c	2018-02-28 10:40:01.662000000 -0500
+@@ -794,6 +794,27 @@
+ 	if (sort_segments(&info) < 0) {
+ 		return -1;
+ 	}
++
++#if 1
++	// force segment 0 to have memsz == bufsz
++	// so that it won't overwrite EBDA
++	if (info.segment[0].mem == 0)
++	{
++		if (kexec_debug)
++			printf("hack ebda into segment 0!\n");
++
++		uint8_t * ebda = calloc(1, info.segment[0].memsz);
++		memcpy(ebda, info.segment[0].buf, info.segment[0].bufsz);
++		info.segment[0].bufsz = info.segment[0].memsz;
++		info.segment[0].buf = ebda;
++
++		// install some default EBDA values that are off scale,
++		// which will force Xen to use the multiboot info
++		*(uint16_t*)(ebda + 0x40e) = 0xFFFF; // segment
++		*(uint16_t*)(ebda + 0x413) = 0xFFFF; // size
++	}
++#endif
++
+ 	/* if purgatory is loaded update it */
+ 	update_purgatory(&info);
+ 	if (entry)
+diff -u --recursive clean/kexec-tools-2.0.16/purgatory/Makefile kexec-tools-2.0.16/purgatory/Makefile
+--- clean/kexec-tools-2.0.16/purgatory/Makefile	2017-01-31 06:23:48.000000000 -0500
++++ kexec-tools-2.0.16/purgatory/Makefile	2018-02-28 05:39:20.461000000 -0500
+@@ -44,7 +44,6 @@
+ 	mkdir -p $(@D)
+ 	$(COMPILE.c) -o $@ $^
+
+-$(PURGATORY): CC=$(TARGET_CC)
+ $(PURGATORY): CFLAGS+=$(PURGATORY_EXTRA_CFLAGS) \
+ 		      $($(ARCH)_PURGATORY_EXTRA_CFLAGS) \
+ 		      -Os -fno-builtin -ffreestanding \
+diff -u --recursive clean/kexec-tools-2.0.16/util/Makefile kexec-tools-2.0.16/util/Makefile
+--- clean/kexec-tools-2.0.16/util/Makefile	2010-07-29 05:22:16.000000000 -0400
++++ kexec-tools-2.0.16/util/Makefile	2018-02-28 05:39:20.461000000 -0500
+@@ -2,7 +2,7 @@
+
+ $(BIN_TO_HEX): $(srcdir)/util/bin-to-hex.c
+ 	@$(MKDIR) -p $(@D)
+-	$(LINK.o) $(CFLAGS) -o $@ $^
++	$(BUILD_CC) $(BUILD_CFLAGS) -o $@ $^
+
+ $(BIN_TO_HEX): CC=$(BUILD_CC)
+ $(BIN_TO_HEX): CFLAGS=$(BUILD_CFLAGS)