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>

diff --git a/Makefile b/Makefile
index c01afc9..19ac8f5 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -231,8 +231,8 @@ endif
 
 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 += $(CPUDIR)/resetvec.o
@@ -241,7 +241,7 @@ ifeq ($(CPU),mpc85xx)
 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)
 

diff --git a/README b/README
index 67ff03a..b9a3685 100644 (file)
--- a/README
+++ b/README
@@ -3664,6 +3664,10 @@ Low Level (hardware related) configuration options:
                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:
 -----------------------------------
 

diff --git a/arch/x86/cpu/Makefile b/arch/x86/cpu/Makefile
index 7f1fc18..be27dd9 100644 (file)
--- a/arch/x86/cpu/Makefile
+++ b/arch/x86/cpu/Makefile
@@ -28,12 +28,13 @@ include $(TOPDIR)/config.mk
 
 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)
 

diff --git a/arch/x86/cpu/u-boot.lds b/arch/x86/cpu/u-boot.lds
index a1ecefa..0c6f0e3 100644 (file)
--- a/arch/x86/cpu/u-boot.lds
+++ b/arch/x86/cpu/u-boot.lds
@@ -86,6 +86,8 @@ SECTIONS
        __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
@@ -95,4 +97,5 @@ SECTIONS
 
        . = RESET_VEC_LOC;
        .resetvec : AT (CONFIG_SYS_TEXT_BASE + (CONFIG_SYS_MONITOR_LEN - RESET_SEG_SIZE + RESET_VEC_LOC)) { KEEP(*(.resetvec)); }
+#endif
 }