libpayload: Inject head.S into libc, remove separate class

Integrate head.S directly into libc and remove all instances of head.o.

* Drop 'separate class' entry for head.S.
* Drop special treament for head.o inside lpgcc.
* Change the .text in `x86/head.S` to `.section .text._entry`.
* Drop arch/mock/head.c, initially added as a dummy file.

Change-Id: I156d781908fcc38d455bbf9f2c29e5ab95c7775a
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82478
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

8 files changed, 8 insertions, 34 deletions

diff --git a/payloads/libpayload/Makefile.mk b/payloads/libpayload/Makefile.mk
index afaa06dd3d..d654995889 100644
--- a/payloads/libpayload/Makefile.mk
+++ b/payloads/libpayload/Makefile.mk
@@ -56,7 +56,6 @@ classes-$(CONFIG_LP_REMOTEGDB) += libgdb
 classes-$(CONFIG_LP_VBOOT_LIB) += vboot_fw
 classes-$(CONFIG_LP_VBOOT_LIB) += tlcl
 libraries := $(classes-y)
-classes-y += head.o
 
 subdirs-y := arch/$(ARCHDIR-y)
 subdirs-y += crypto libc drivers libpci gdb
@@ -97,7 +96,7 @@ $(obj)/libpayload-config.h: $(KCONFIG_AUTOHEADER) $(obj)/libpayload.config
 	cmp $@ $< 2>/dev/null || cp $< $@
 
 library-targets = $(addsuffix .a,$(addprefix $(obj)/,$(libraries))) $(obj)/libpayload.a
-lib: $$(library-targets) $(obj)/head.o
+lib: $$(library-targets)
 
 extract_nth=$(word $(1), $(subst |, ,$(2)))
 
@@ -116,17 +115,12 @@ $(obj)/%.a: $$(%-objs)
 	printf "    AR         $(subst $(CURDIR)/,,$(@))\n"
 	printf "create $@\n$(foreach objc,$(filter-out %.a,$^),addmod $(objc)\n)$(foreach lib,$(filter %.a,$^),addlib $(lib)\n)save\nend\n" | $(AR) -M
 
-$(obj)/head.o: $(obj)/arch/$(ARCHDIR-y)/head.head.o.o
-	printf "    CP         $(subst $(CURDIR)/,,$(@))\n"
-	cp $^ $@
-
 install: real-target
 	printf "    INSTALL    $(DESTDIR)/libpayload/lib\n"
 	install -m 755 -d $(DESTDIR)/libpayload/lib
 	install -m 644 $(library-targets) $(DESTDIR)/libpayload/lib/
 	install -m 644 arch/$(ARCHDIR-y)/libpayload.ldscript $(DESTDIR)/libpayload/lib/
 	install -m 755 -d $(DESTDIR)/libpayload/lib/$(ARCHDIR-y)
-	install -m 644 $(obj)/head.o $(DESTDIR)/libpayload/lib/$(ARCHDIR-y)
 	printf "    INSTALL    $(DESTDIR)/libpayload/include\n"
 	install -m 755 -d $(DESTDIR)/libpayload/include
 	find include -type d -exec install -m755 -d $(DESTDIR)/libpayload/{} \;
diff --git a/payloads/libpayload/arch/arm/Makefile.mk b/payloads/libpayload/arch/arm/Makefile.mk
index f71138baaa..e6574e7782 100644
--- a/payloads/libpayload/arch/arm/Makefile.mk
+++ b/payloads/libpayload/arch/arm/Makefile.mk
@@ -29,7 +29,7 @@
 CFLAGS += -mthumb -march=armv7-a
 arm_asm_flags = -Wa,-mthumb -Wa,-mimplicit-it=always -Wa,-mno-warn-deprecated
 
-head.o-y += head.S
+libc-y += head.S
 libc-y += eabi_compat.c
 libc-y += main.c sysinfo.c
 libc-y += timer.c coreboot.c util.S
@@ -44,5 +44,4 @@ libc-$(CONFIG_LP_GPL) += memcpy.S memset.S memmove.S
 libgdb-y += gdb.c
 
 # Add other classes here when you put assembly files into them!
-head.o-S-ccopts += $(arm_asm_flags)
 libc-S-ccopts += $(arm_asm_flags)
diff --git a/payloads/libpayload/arch/arm64/Makefile.mk b/payloads/libpayload/arch/arm64/Makefile.mk
index b478c77bce..d6cc51efdf 100644
--- a/payloads/libpayload/arch/arm64/Makefile.mk
+++ b/payloads/libpayload/arch/arm64/Makefile.mk
@@ -29,7 +29,7 @@
 CFLAGS += -march=armv8-a
 arm64_asm_flags =
 
-head.o-y += head.S
+libc-y += head.S
 libc-y += main.c sysinfo.c
 libc-y += timer.c coreboot.c util.S
 libc-y += virtual.c
@@ -42,5 +42,4 @@ libc-y += mmu.c
 libgdb-y += gdb.c
 
 # Add other classes here when you put assembly files into them!
- head.o-S-ccopts += $(arm64_asm_flags)
- libc-S-ccopts += $(arm64_asm_flags)
+libc-S-ccopts += $(arm64_asm_flags)
diff --git a/payloads/libpayload/arch/mock/Makefile.mk b/payloads/libpayload/arch/mock/Makefile.mk
index e3f10a69ed..0b418f0d97 100644
--- a/payloads/libpayload/arch/mock/Makefile.mk
+++ b/payloads/libpayload/arch/mock/Makefile.mk
@@ -1,7 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
-head.o-y += head.c
-
 libc-y += virtual.c
 
 CFLAGS += -Wno-address-of-packed-member
diff --git a/payloads/libpayload/arch/mock/head.c b/payloads/libpayload/arch/mock/head.c
deleted file mode 100644
index 55a691f910..0000000000
--- a/payloads/libpayload/arch/mock/head.c
+++ /dev/null
@@ -1,3 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-
-/* This file is empty on purpose. It should not be used. */
diff --git a/payloads/libpayload/arch/x86/Makefile.mk b/payloads/libpayload/arch/x86/Makefile.mk
index 196415d7a2..d2c33b4fb8 100644
--- a/payloads/libpayload/arch/x86/Makefile.mk
+++ b/payloads/libpayload/arch/x86/Makefile.mk
@@ -30,7 +30,7 @@ ifneq ($(CONFIG_LP_COMPILER_LLVM_CLANG),y)
 CFLAGS += -mpreferred-stack-boundary=2
 endif
 
-head.o-y += head.S
+libc-y += head.S
 libc-y += main.c sysinfo.c
 libc-y += timer.c coreboot.c util.S
 libc-y += exec.S virtual.c
diff --git a/payloads/libpayload/arch/x86/head.S b/payloads/libpayload/arch/x86/head.S
index 99842cd54b..26ba901d5a 100644
--- a/payloads/libpayload/arch/x86/head.S
+++ b/payloads/libpayload/arch/x86/head.S
@@ -29,7 +29,7 @@
 
 	.code32
 	.global _entry
-	.text
+	.section .text._entry
 	.align 4
 
 /*
diff --git a/payloads/libpayload/bin/lpgcc b/payloads/libpayload/bin/lpgcc
index 724f5eca64..a954d4ff5b 100755
--- a/payloads/libpayload/bin/lpgcc
+++ b/payloads/libpayload/bin/lpgcc
@@ -201,14 +201,6 @@ if [ $DOLINK -eq 0 ]; then
     $DEFAULT_CC $CMDLINE $_CFLAGS
 else
     _LIBGCC=`$DEFAULT_CC $_ARCHEXTRA -print-libgcc-file-name`
-    if [ -f $_ARCHLIBDIR/head.o ]; then
-	    HEAD_O=$_ARCHLIBDIR/head.o
-    elif [ -f $_OBJ/head.o ]; then
-	    HEAD_O=$_OBJ/head.o
-    else
-	    echo "Could not find head.o"
-	    exit 1
-    fi
 
     if [ "$CONFIG_LP_ARM64_A53_ERRATUM_843419" = y ] &&
        grep -q fix-cortex-a53-843419 $_XCOMPILE; then
@@ -220,13 +212,8 @@ else
     _LDFLAGS="$_LDFLAGS -Wl,--defsym=CONFIG_LP_STACK_SIZE=$CONFIG_LP_STACK_SIZE"
 
     if [ $DEBUGME -eq 1 ]; then
-	echo "$DEFAULT_CC $_LDFLAGS $HEAD_O $CMDLINE $_CFLAGS -lpayload $_LIBGCC"
+	echo "$DEFAULT_CC $_LDFLAGS $CMDLINE $_CFLAGS -lpayload $_LIBGCC"
     fi
 
-    # Note: $_ARCHLIBDIR/head.o must be the first object being linked, because it
-    # contains a Multiboot header.  The Multiboot standard requires this
-    # header to be placed below 0x2000 in the resulting image.  See:
-    # http://www.gnu.org/software/grub/manual/multiboot/html_node/OS-image-format.html
-
-    $DEFAULT_CC $_LDFLAGS $HEAD_O $CMDLINE $_CFLAGS -lpayload -xnone $_LIBGCC
+    $DEFAULT_CC $_LDFLAGS $CMDLINE $_CFLAGS -lpayload -xnone $_LIBGCC
 fi