x86, galileo: Add UEFI support

This patch adds support for optionally building EFI binaries in
addition to Multiboot ELF binaries.  It includes a script,
build_uefi.sh, that downloads tool and library sources from the EDK II
project, builds the GenFw tool that is used to create UEFI binaries,
and creates a makefile that is included from the main x86 common
makefile and enables UEFI support in the Contiki build system.  If the
script is not run prior to building Contiki, then an informational
message will be displayed with instructions for running build_uefi.sh
if UEFI support is desired.  This patch also adds the path to the
auto-generated makefile to .gitignore.

This patch modifies the linker script for the Intel Quark X1000 to
account for the output file section offsets and alignment expectations
of the EDK II GenFw project.

This patch also adds a newlib patch to remove the weak symbol
attribute from floating point stdio support routines.  See
<newlib>/newlib/README for an explanation of how the newlib developers
intended for _printf_float and _scanf_float to be linked.  Newlib
declares them as weak symbols with the intention that developers would
force them to be linked only when needed using a linker command line
option.  However, some but not all Contiki programs require them, so
we cannot simply always include or exclude them.  Instead, we remove
the weak symbol attributes and rely on the linker to automatically
determine whether or not they should be linked.  This avoids an issue
in which weak symbols were undefined in the intermediate DLL generated
as part of the UEFI build process.  That resulted in the GenFw program
emitting "ERROR 3000" messages when it encountered relocations
referencing such an undefined symbol.

Finally, this patch updates README.md to both make some revisions to
account for the UART support introduced in previous patches as well as
to provide instructions for using the UEFI support.

.gitignore

@@ -111,6 +111,10 @@ cscope.*
 *.swp
 *.swo
 
+# x86 UEFI files
+cpu/x86/uefi/Makefile.uefi
+cpu/x86/uefi/edk2
+
 # galileo bsp files
 platform/galileo/bsp/libc/Makefile.libc
 platform/galileo/bsp/libc/i586-elf/
@@ -120,4 +124,6 @@ platform/galileo/bsp/grub/bin/
 
 # galileo build and debug artefacts
 *.galileo
+*.galileo.dll
+*.galileo.efi
 LOG_OPENOCD

cpu/x86/Makefile.x86_common

@@ -14,6 +14,12 @@ STRIP    = strip
 # tables saves space and has not caused any readily-apparent functional
 # changes.
 #
+# Furthermore, the .eh_frame and .eh_frame_hdr sections that are otherwise
+# generated are treated as code sections by the UEFI GenFw program, since they
+# are read-only alloc sections.  They get grouped with the actual code
+# sections, ahead of the data sections.  This perturbs symbols and complicates
+# debugging.
+#
 # Synchronize the unwind table options here with the CFLAGS and CXXFLAGS in
 # ./bsp/libc/build_newlib.sh.
 CFLAGS  += -Wall -fno-asynchronous-unwind-tables -fno-unwind-tables
@@ -23,7 +29,9 @@ ifeq ($(BUILD_RELEASE),1)
 	CFLAGS  += -Os -fno-strict-aliasing -ffunction-sections -fdata-sections
 # XXX: --gc-sections can be very tricky sometimes. If somehow the release
 # binary seems to be broken, check if removing this option fixes the issue.
-	LDFLAGS += -Wl,--strip-all,--gc-sections
+# Applying the --strip-all option to the UEFI build may induce an "Invalid operation" error.
+# The UEFI GenFw program strips symbols.
+	MULTIBOOT_LDFLAGS += -Wl,--strip-all,--gc-sections
 else
   CFLAGS  += -O0
 	ifeq ($(findstring clang,$(CC)),clang)

cpu/x86/Makefile.x86_quarkX1000

@@ -7,3 +7,31 @@ CONTIKI_SOURCEFILES += bootstrap_quarkX1000.S rtc.c pit.c pic.c irq.c nmi.c pci.
 CFLAGS += -m32 -march=i586 -mtune=i586
 LDFLAGS += -m32 -Xlinker -T -Xlinker $(CONTIKI)/cpu/x86/quarkX1000.ld
 ASFLAGS += --32 -march=i586 -mtune=i586
+
+### UEFI support
+
+UEFI_DIR = $(CONTIKI_CPU)/uefi
+
+ifndef EN_UEFI
+# Include a Makefile generated by the build_uefi.sh script, if available.
+# If that script was not run, then UEFI support will not be built.
+-include $(UEFI_DIR)/Makefile.uefi
+endif
+
+ifeq ($(EN_UEFI),1)
+	EDK2_DIR = $(UEFI_DIR)/edk2
+
+	GEN_FW = $(EDK2_DIR)/BaseTools/Source/C/bin/GenFw
+
+	CONTIKI_CPU_DIRS += uefi
+	CONTIKI_SOURCEFILES += bootstrap_uefi.c
+	CFLAGS += -I$(EDK2_DIR)/MdePkg/Include -I$(EDK2_DIR)/MdePkg/Include/Ia32
+else
+    $(info Note: UEFI support is disabled.)
+    ifndef EN_UEFI
+        $(info To enable UEFI support, run $(CONTIKI_CPU)/uefi/build_uefi.sh prior)
+        $(info to building Contiki.)
+    else
+        $(info LTO and UEFI support are mututally-exclusive.)
+    endif
+endif

cpu/x86/quarkX1000.ld

@@ -36,26 +36,39 @@ SECTIONS {
     /*
        OS-Dev Wiki says it is common for kernels to start at 1M. Addresses before that
        are used by BIOS/EFI, the bootloader and memory-mapped I/O.
-    */
-    . = 1M;
 
-    .text ALIGN (4K) :
+       The UEFI GenFw program inserts a 0x240-byte offset between the image base and
+       the .text section.  We add that same offset here to align the symbols in the
+       UEFI DLL with those in the final UEFI binary to make debugging easier.  We also
+       apply 32-byte alignments to sections rather than more conventional 4K-byte
+       alignments to avoid symbols being shifted from the intermediate DLL to the
+       final UEFI image as would occur if the GenFw program shifted the .text section
+       from a higher, 4K-aligned offset to the 0x240-byte offset from the image base.
+       Such shifting may make debugging more difficult by preventing the DLL from
+       being a directly-useful source of symbol information.  The debugging symbols
+       are not included in the final UEFI image.  The GenFw program uses a minimum
+       section alignment of 32 bytes, so smaller alignment granularities may also
+       result in symbol perturbation.
+    */
+    . = 1M + 0x240;
+
+    .text ALIGN (32) :
     {
         KEEP(*(.multiboot))
         *(.text*)
     }
 
-    .rodata ALIGN (4K) :
+    .rodata ALIGN (32) :
     {
         *(.rodata*)
     }
 
-    .data ALIGN (4K) :
+    .data ALIGN (32) :
     {
         *(.data*)
     }
 
-    .bss ALIGN (4K) :
+    .bss ALIGN (32) :
     {
         *(COMMON)
         *(.bss*)

cpu/x86/uefi/bootstrap_uefi.c

@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2015, Intel Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <Uefi.h>
+#include <Protocol/LoadedImage.h>
+
+#define MAX_MEM_DESC 128
+
+void start(void);
+
+EFI_STATUS EFIAPI
+uefi_start(IN EFI_HANDLE ImageHandle, IN EFI_SYSTEM_TABLE *SystemTable)
+{
+  EFI_MEMORY_DESCRIPTOR mem_map[MAX_MEM_DESC];
+  UINTN mem_map_len = sizeof(mem_map);
+  UINTN mem_map_key;
+  UINTN mem_map_desc_sz;
+  UINT32 mem_map_rev;
+
+  EFI_STATUS res;
+
+  res = SystemTable->BootServices->GetMemoryMap(&mem_map_len,
+                                                mem_map,
+                                                &mem_map_key,
+                                                &mem_map_desc_sz,
+                                                &mem_map_rev);
+  if(res != EFI_SUCCESS) {
+    return EFI_ABORTED;
+  }
+
+  res = SystemTable->BootServices->ExitBootServices(ImageHandle, mem_map_key);
+  if(res != EFI_SUCCESS) {
+    return EFI_ABORTED;
+  }
+
+  start();
+
+  /* Should not be reachable: */
+  return EFI_SUCCESS;
+}

cpu/x86/uefi/build_uefi.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+SCRIPT_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
+
+# This script will always run on its own basepath, no matter where you call it from.
+pushd ${SCRIPT_DIR}
+
+# Download the UEFI tool and library sources:
+git clone --depth=1 https://github.com/tianocore/edk2 || exit
+# This script only supports building the tools on 64-bit hosts:
+export ARCH=X64
+# Build common sources required by the GenFw tool:
+make -C edk2/BaseTools/Source/C/Common || exit
+# Build the GenFw tool that is used to generate UEFI binaries:
+make -C edk2/BaseTools/Source/C/GenFw || exit
+# Create a makefile that indicates to the Contiki build system that UEFI support
+# should be built:
+echo "EN_UEFI = 1" > Makefile.uefi
+
+popd

platform/galileo/Makefile.customrules-galileo

@@ -1,15 +1,48 @@
 GDB ?= gdb
 OPENOCD_SCRIPTS = $(CONTIKI)/platform/galileo/bsp/openocd-scripts
 
-.PHONY: debug
+.PHONY: debug $(CONTIKI_PROJECT)
 
-debug: $(CONTIKI_PROJECT).$(TARGET)
+# Multiboot ELF binary
+MULTIBOOT_SFX = $(TARGET)
+MULTIBOOT = $(CONTIKI_PROJECT).$(MULTIBOOT_SFX)
+# UEFI binary
+UEFI_DLL_SFX = $(TARGET).dll
+UEFI_DLL = $(CONTIKI_PROJECT).$(UEFI_SFX)
+UEFI_LDFLAGS += -Xlinker --emit-relocs -Xlinker --entry=uefi_start
+UEFI_SFX = $(TARGET).efi
+UEFI = $(CONTIKI_PROJECT).$(UEFI_SFX)
+
+# Suffixes for final (non-intermediate) files to be built
+FINAL_SFXS = $(MULTIBOOT_SFX)
+ifeq ($(EN_UEFI),1)
+FINAL_SFXS += $(UEFI_SFX)
+endif
+
+debug: $(MULTIBOOT)
 	@openocd -s $(OPENOCD_SCRIPTS) -f debug.cfg &> $(shell pwd)/LOG_OPENOCD &
 	@$(GDB) $< -ex "target remote :3333"
 
 CUSTOM_RULE_LINK=1
-%.$(TARGET): %.co $(PROJECT_OBJECTFILES) $(PROJECT_LIBRARIES) contiki-$(TARGET).a
+define LINK_template =
-	$(TRACE_LD)
+%.$(1): %.co $$(PROJECT_OBJECTFILES) $$(PROJECT_LIBRARIES) contiki-$$(TARGET).a
-	$(Q)$(LD) $(LDFLAGS) $(TARGET_STARTFILES) ${filter-out %.a,$^} \
+	$$(TRACE_LD)
-	    ${filter %.a,$^} $(TARGET_LIBFILES) -o $@
+	$$(Q)$$(LD) $$(LDFLAGS) $(2) $$(TARGET_STARTFILES) $${filter-out %.a,$$^} \
-	@$(SIZE) $@
+	    $${filter %.a,$$^} $$(TARGET_LIBFILES) -o $$@
+endef
+
+$(eval $(call LINK_template,$(MULTIBOOT_SFX),$(MULTIBOOT_LDFLAGS)))
+$(eval $(call LINK_template,$(UEFI_DLL_SFX),$(UEFI_LDFLAGS)))
+
+%.$(UEFI_SFX): %.$(UEFI_DLL_SFX)
+	$(Q)$(GEN_FW) -o $@ -e UEFI_APPLICATION $^
+    # The Intel Galileo firmware has been observed to not relocate the image
+    # if its base is set to the 1M boundary.  This makes debugging easier,
+    # since the symbols in the intermediate DLL then correspond to the load
+    # addresses.
+	$(Q)$(GEN_FW) -o $@ --rebase 0x100000 $@
+
+$(CONTIKI_PROJECT): $(addprefix $(CONTIKI_PROJECT).,$(FINAL_SFXS))
+	@$(SIZE) $^
+
+CLEAN += $(addprefix $(CONTIKI_PROJECT).,$(FINAL_SFXS))

platform/galileo/README.md

@@ -71,6 +71,12 @@ You can also build a "Release" image by setting the BUILD_RELEASE variable to
 $ cd examples/hello-world/ && make TARGET=galileo BUILD_RELEASE=1
 ```
 
+To also generate an '<application>.galileo.efi' file which is a UEFI [4] image,
+you can run the following command prior to building applications:
+```
+$ cpu/x86/uefi/build_uefi.sh
+```
+
 Running
 -------
 
@@ -90,6 +96,8 @@ detailed instructions.
 
 Mount the sdcard in directory /mnt/sdcard.
 
+#### Approach for Multiboot-compliant ELF Image
+
 Copy Contiki binary image to sdcard
 ```
 $ cp examples/hello-world/hello-world.galileo /mnt/sdcard
@@ -100,6 +108,13 @@ Copy grub binary to sdcard
 $ cp platform/galileo/bsp/grub/bin/grub.efi /mnt/sdcard
 ```
 
+#### Approach for UEFI Image
+
+Copy Contiki binary image to sdcard
+```
+$ cp examples/hello-world/hello-world.galileo.efi /mnt/sdcard
+```
+
 ### Connect to the console output
 
 Connect the serial cable to your computer as shown in [2].
@@ -117,8 +132,11 @@ Press [Enter] to directly boot.
 Press [F7]    to show boot menu options.
 ```
 
-Press <F7> and select the option "UEFI Internal Shell" within the menu. Once
+Press <F7> and select the option "UEFI Internal Shell" within the menu.
-you have a shell, run the following commands to run grub application:
+
+#### Boot Multiboot-compliant ELF Image
+
+Once you have a shell, run the following commands to run grub application:
 ```
 $ fs0:
 $ grub.efi
@@ -131,6 +149,16 @@ $ multiboot /hello-world.galileo
 $ boot
 ```
 
+#### Boot UEFI Image
+
+Once you have a shell, run the following commands to boot Contiki image:
+```
+$ fs0:
+$ hello-world.galileo.efi
+```
+
+### Verify that Contiki is Running
+
 This should boot the Contiki image, resulting in the following messages being
 sent to the serial console:
 ```
@@ -176,3 +204,5 @@ References
 [2] http://www.intel.com/support/galileo/sb/CS-035124.htm
 
 [3] https://www.gnu.org/software/grub/manual/multiboot/multiboot.html
+
+[4] http://www.uefi.org/

platform/galileo/bsp/libc/patches/stdio_strengthen_syms.patch

@@ -0,0 +1,19 @@
+--- newlib/libc/stdio/nano-vfprintf_local.h	2014-07-04 10:21:43.000000000 -0700
++++ newlib/libc/stdio/nano-vfprintf_local.h	2015-07-17 12:51:12.974269921 -0700
+@@ -230,5 +230,5 @@ _printf_float (struct _reent *data,
+ 	       FILE *fp,
+ 	       int (*pfunc)(struct _reent *, FILE *,
+ 			    _CONST char *, size_t len),
+-	       va_list *ap) _ATTRIBUTE((__weak__));
++	       va_list *ap);
+ #endif
+--- newlib/libc/stdio/nano-vfscanf_local.h	2014-07-04 10:21:44.000000000 -0700
++++ newlib/libc/stdio/nano-vfscanf_local.h	2015-07-17 12:51:33.967362409 -0700
+@@ -173,6 +173,6 @@ _scanf_i (struct _reent *rptr,
+ extern int
+ _scanf_float (struct _reent *rptr,
+ 	      struct _scan_data_t *pdata,
+-	      FILE *fp, va_list *ap) _ATTRIBUTE((__weak__));
++	      FILE *fp, va_list *ap);
+ 
+ #endif