[Xen-devel] [PATCH v2 10/23] efi: build xen.gz with EFI code

[Daniel Kiper <daniel.kiper@xxxxxxxxxx>]

Build xen.gz with EFI code. We need this to support multiboot2
protocol on EFI platforms.

If we wish to load not ELF file using multiboot (v1) or multiboot2 then
it must contain "linear" (or "flat") representation of code and data.
Currently, PE file contains many sections which are not "linear" (one
after another without any holes) or even do not have representation
in a file (e.g. BSS). In theory there is a chance that we could build
proper PE file using current build system. However, it means that
xen.efi further diverge from xen ELF file (in terms of contents and
build method). ELF have all needed properties. So, it means that this
is good starting point for further development. Additionally, I think
that this is also good starting point for further xen.efi code and
build optimizations. It looks that there is a chance that finally we
can generate xen.efi directly from xen ELF using just simple objcopy.

Signed-off-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
---
v2 - suggestions/fixes:
   - build EFI code only if it is supported in a given build environment
     (suggested by Jan Beulich).
---
 xen/arch/x86/Makefile     |   13 +++++--------
 xen/arch/x86/efi/Makefile |   16 +++++++++-------
 xen/arch/x86/mm.c         |    3 ++-
 xen/common/efi/runtime.c  |    6 ++++++
 4 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 5f24951..0335445 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -80,7 +80,7 @@ ALL_OBJS := $(BASEDIR)/arch/x86/boot/built_in.o 
$(BASEDIR)/arch/x86/efi/built_in
 
 ifeq ($(lto),y)
 # Gather all LTO objects together
-prelink_lto.o: $(ALL_OBJS)
+prelink_lto.o: $(ALL_OBJS) efi/relocs-dummy.o
        $(LD_LTO) -r -o $@ $^
 
 prelink-efi_lto.o: $(ALL_OBJS) efi/runtime.o efi/compat.o
@@ -90,14 +90,14 @@ prelink-efi_lto.o: $(ALL_OBJS) efi/runtime.o efi/compat.o
 prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o
        $(LD) $(LDFLAGS) -r -o $@ $^
 
-prelink-efi.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) 
prelink-efi_lto.o efi/boot.init.o
+prelink-efi.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) 
prelink-efi_lto.o
        $(guard) $(LD) $(LDFLAGS) -r -o $@ $^
 else
-prelink.o: $(ALL_OBJS)
+prelink.o: $(ALL_OBJS) efi/relocs-dummy.o
        $(LD) $(LDFLAGS) -r -o $@ $^
 
-prelink-efi.o: $(ALL_OBJS) efi/boot.init.o efi/runtime.o efi/compat.o
-       $(guard) $(LD) $(LDFLAGS) -r -o $@ $(filter-out %/efi/built_in.o,$^)
+prelink-efi.o: $(ALL_OBJS)
+       $(guard) $(LD) $(LDFLAGS) -r -o $@ $^
 endif
 
 $(BASEDIR)/common/symbols-dummy.o:
@@ -146,9 +146,6 @@ $(TARGET).efi: prelink-efi.o efi.lds efi/relocs-dummy.o 
$(BASEDIR)/common/symbol
        if $(guard) false; then rm -f $@; echo 'EFI support disabled'; fi
        rm -f $(@D)/.$(@F).[0-9]*
 
-efi/boot.init.o efi/runtime.o efi/compat.o: $(BASEDIR)/arch/x86/efi/built_in.o
-efi/boot.init.o efi/runtime.o efi/compat.o: ;
-
 asm-offsets.s: $(TARGET_SUBARCH)/asm-offsets.c
        $(CC) $(filter-out -flto,$(CFLAGS)) -S -o $@ $<
 
diff --git a/xen/arch/x86/efi/Makefile b/xen/arch/x86/efi/Makefile
index 1daa7ac..b1e8883 100644
--- a/xen/arch/x86/efi/Makefile
+++ b/xen/arch/x86/efi/Makefile
@@ -1,14 +1,16 @@
 CFLAGS += -fshort-wchar
 
-obj-y += stub.o
-
-create = test -e $(1) || touch -t 199901010000 $(1)
-
 efi := $(filter y,$(x86_64)$(shell rm -f disabled))
 efi := $(if $(efi),$(shell $(CC) $(filter-out $(CFLAGS-y) .%.d,$(CFLAGS)) -c 
check.c 2>disabled && echo y))
 efi := $(if $(efi),$(shell $(LD) -mi386pep --subsystem=10 -o check.efi check.o 
2>disabled && echo y))
-efi := $(if $(efi),$(shell rm disabled)y,$(shell $(call create,boot.init.o); 
$(call create,runtime.o)))
+efi := $(if $(efi),$(shell rm disabled)y)
 
-extra-$(efi) += boot.init.o relocs-dummy.o runtime.o compat.o
+extra-y += relocs-dummy.o
 
-stub.o: $(extra-y)
+ifeq ($(efi),y)
+obj-y += boot.init.o
+obj-y += compat.o
+obj-y += runtime.o
+else
+obj-y += stub.o
+endif
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 342414f..cef2eb6 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -344,7 +344,8 @@ void __init arch_init_memory(void)
 
     subarch_init_memory();
 
-    efi_init_memory();
+    if ( efi_enabled(EFI_PLATFORM) )
+        efi_init_memory();
 
     mem_sharing_init();
 
diff --git a/xen/common/efi/runtime.c b/xen/common/efi/runtime.c
index aa064e7..3eb21c1 100644
--- a/xen/common/efi/runtime.c
+++ b/xen/common/efi/runtime.c
@@ -167,6 +167,9 @@ int efi_get_info(uint32_t idx, union xenpf_efi_info *info)
 {
     unsigned int i, n;
 
+    if ( !efi_enabled(EFI_PLATFORM) )
+        return -EOPNOTSUPP;
+
     switch ( idx )
     {
     case XEN_FW_EFI_VERSION:
@@ -301,6 +304,9 @@ int efi_runtime_call(struct xenpf_efi_runtime_call *op)
     EFI_STATUS status = EFI_NOT_STARTED;
     int rc = 0;
 
+    if ( !efi_enabled(EFI_PLATFORM) )
+        return -EOPNOTSUPP;
+
     switch ( op->function )
     {
     case XEN_EFI_get_time:
-- 
1.7.10.4


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