x86: Allow excluding reset vector code from u-boot

When running from coreboot we don't want this code. This version works by ifdef-ing out all of the code that would go into those sections and all the code that refers to it. The sections are then empty, and the linker will either leave them empty for the loader to ignore or remove them entirely. Signed-off-by: Gabe Black <gabeblack@chromium.org> Signed-off-by: Simon Glass <sjg@chromium.org>

x86: Allow excluding reset vector code from u-boot
When running from coreboot we don't want this code. This version works by ifdef-ing out all of the code that would go into those sections and all the code that refers to it. The sections are then empty, and the linker will either leave them empty for the loader to ignore or remove them entirely. Signed-off-by: Gabe Black <gabeblack@chromium.org> Signed-off-by: Simon Glass <sjg@chromium.org>
Gabe Black · Simon Glass
1 parent 8a487a4417
Showing 4 changed files with 13 additions and 5 deletions Side-by-side Diff
Makefile
README
arch/x86/cpu/Makefile
arch/x86/cpu/u-boot.lds
@@ -231,8 +231,8 @@
  
 OBJS  = $(CPUDIR)/start.o
 ifeq ($(CPU),x86)
-OBJS += $(CPUDIR)/start16.o
-OBJS += $(CPUDIR)/resetvec.o
+RESET_OBJS-$(CONFIG_X86_NO_RESET_VECTOR) += $(CPUDIR)/start16.o
+RESET_OBJS-$(CONFIG_X86_NO_RESET_VECTOR) += $(CPUDIR)/resetvec.o
 endif
 ifeq ($(CPU),ppc4xx)
 OBJS += $(CPUDIR)/resetvec.o
@@ -241,7 +241,7 @@
 OBJS += $(CPUDIR)/resetvec.o
 endif
  
-OBJS := $(addprefix $(obj),$(OBJS))
+OBJS := $(addprefix $(obj),$(OBJS) $(RESET_OBJS-))
  
 HAVE_VENDOR_COMMON_LIB = $(if $(wildcard board/$(VENDOR)/common/Makefile),y,n)
  
@@ -3664,6 +3664,10 @@
 		be used if available. These functions may be faster under some
 		conditions but may increase the binary size.
  
+- CONFIG_X86_NO_RESET_VECTOR
+		If defined, the x86 reset vector code is excluded. You will need
+		to do this when U-Boot is running from Coreboot.
+
 Freescale QE/FMAN Firmware Support:
 -----------------------------------
  
@@ -28,12 +28,13 @@
  
 LIB	= $(obj)lib$(CPU).o
  
-START	= start.o start16.o resetvec.o
+START-y	= start.o
+RESET_OBJS-$(CONFIG_X86_NO_RESET_VECTOR) += resetvec.o start16.o
 COBJS	= interrupts.o cpu.o
  
 SRCS	:= $(START:.o=.S) $(SOBJS:.o=.S) $(COBJS:.o=.c)
 OBJS	:= $(addprefix $(obj),$(SOBJS) $(COBJS))
-START	:= $(addprefix $(obj),$(START))
+START	:= $(addprefix $(obj),$(START-y) $(RESET_OBJS-))
  
 all:	$(obj).depend $(START) $(LIB)
  
@@ -86,6 +86,8 @@
 	__bios_start = LOADADDR(.bios);
 	__bios_size = SIZEOF(.bios);
  
+#ifndef CONFIG_X86_NO_RESET_VECTOR
+
 	/*
 	 * The following expressions place the 16-bit Real-Mode code and
 	 * Reset Vector at the end of the Flash ROM
@@ -95,5 +97,6 @@
  
 	. = RESET_VEC_LOC;
 	.resetvec : AT (CONFIG_SYS_TEXT_BASE + (CONFIG_SYS_MONITOR_LEN - RESET_SEG_SIZE + RESET_VEC_LOC)) { KEEP(*(.resetvec)); }
+#endif
 }
...	...	@@ -231,8 +231,8 @@
231	231
232	232	OBJS = $(CPUDIR)/start.o
233	233	ifeq ($(CPU),x86)
234		-OBJS += $(CPUDIR)/start16.o
235		-OBJS += $(CPUDIR)/resetvec.o
	234	+RESET_OBJS-$(CONFIG_X86_NO_RESET_VECTOR) += $(CPUDIR)/start16.o
	235	+RESET_OBJS-$(CONFIG_X86_NO_RESET_VECTOR) += $(CPUDIR)/resetvec.o
236	236	endif
237	237	ifeq ($(CPU),ppc4xx)
238	238	OBJS += $(CPUDIR)/resetvec.o
...	...	@@ -241,7 +241,7 @@
241	241	OBJS += $(CPUDIR)/resetvec.o
242	242	endif
243	243
244		-OBJS := $(addprefix $(obj),$(OBJS))
	244	+OBJS := $(addprefix $(obj),$(OBJS) $(RESET_OBJS-))
245	245
246	246	HAVE_VENDOR_COMMON_LIB = $(if $(wildcard board/$(VENDOR)/common/Makefile),y,n)
247	247
...	...	@@ -3664,6 +3664,10 @@
3664	3664	be used if available. These functions may be faster under some
3665	3665	conditions but may increase the binary size.
3666	3666
	3667	+- CONFIG_X86_NO_RESET_VECTOR
	3668	+ If defined, the x86 reset vector code is excluded. You will need
	3669	+ to do this when U-Boot is running from Coreboot.
	3670	+
3667	3671	Freescale QE/FMAN Firmware Support:
3668	3672	-----------------------------------
3669	3673
...	...	@@ -28,12 +28,13 @@
28	28
29	29	LIB = $(obj)lib$(CPU).o
30	30
31		-START = start.o start16.o resetvec.o
	31	+START-y = start.o
	32	+RESET_OBJS-$(CONFIG_X86_NO_RESET_VECTOR) += resetvec.o start16.o
32	33	COBJS = interrupts.o cpu.o
33	34
34	35	SRCS := $(START:.o=.S) $(SOBJS:.o=.S) $(COBJS:.o=.c)
35	36	OBJS := $(addprefix $(obj),$(SOBJS) $(COBJS))
36		-START := $(addprefix $(obj),$(START))
	37	+START := $(addprefix $(obj),$(START-y) $(RESET_OBJS-))
37	38
38	39	all: $(obj).depend $(START) $(LIB)
39	40
...	...	@@ -86,6 +86,8 @@
86	86	__bios_start = LOADADDR(.bios);
87	87	__bios_size = SIZEOF(.bios);
88	88
	89	+#ifndef CONFIG_X86_NO_RESET_VECTOR
	90	+
89	91	/*
90	92	* The following expressions place the 16-bit Real-Mode code and
91	93	* Reset Vector at the end of the Flash ROM
...	...	@@ -95,5 +97,6 @@
95	97
96	98	. = RESET_VEC_LOC;
97	99	.resetvec : AT (CONFIG_SYS_TEXT_BASE + (CONFIG_SYS_MONITOR_LEN - RESET_SEG_SIZE + RESET_VEC_LOC)) { KEEP(*(.resetvec)); }
	100	+#endif
98	101	}