x86/EFI: redo .reloc section bounds determination

There's no need to link relocs-dummy.o into the ELF binary. The two
symbols needed can as well be provided by the linker script. Then our
mkreloc tool also doesn't need to put them in the generated assembler
source.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>

diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 053206e4f0276c82ed99a529710d76a70774847e..0b4c24112d7b164b9b0d3130540979b402b17734 100644 (file)
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -136,7 +136,6 @@ XEN_NO_PE_FIXUPS := $(if $(XEN_BUILD_EFI), \
 endif
 
 ALL_OBJS := $(BASEDIR)/arch/x86/boot/built_in.o $(BASEDIR)/arch/x86/efi/built_in.o $(ALL_OBJS)
-EFI_OBJS-$(XEN_BUILD_EFI) := efi/relocs-dummy.o
 
 ifeq ($(CONFIG_LTO),y)
 # Gather all LTO objects together
@@ -144,13 +143,13 @@ prelink_lto.o: $(ALL_OBJS) $(ALL_LIBS)
        $(LD_LTO) -r -o $@ $(filter-out %.a,$^) --start-group $(filter %.a,$^) --end-group
 
 # Link it with all the binary objects
-prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o $(EFI_OBJS-y) FORCE
+prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o FORCE
        $(call if_changed,ld)
 
 prelink-efi.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o FORCE
        $(call if_changed,ld)
 else
-prelink.o: $(ALL_OBJS) $(ALL_LIBS) $(EFI_OBJS-y) FORCE
+prelink.o: $(ALL_OBJS) $(ALL_LIBS) FORCE
        $(call if_changed,ld)
 
 prelink-efi.o: $(ALL_OBJS) $(ALL_LIBS) FORCE

diff --git a/xen/arch/x86/efi/mkreloc.c b/xen/arch/x86/efi/mkreloc.c
index 9efeaee7c5d6080aa736e9051972fb06dec9bbe6..083740ab8a0f8bdf211e5eabff62448d066bae08 100644 (file)
--- a/xen/arch/x86/efi/mkreloc.c
+++ b/xen/arch/x86/efi/mkreloc.c
@@ -320,9 +320,7 @@ int main(int argc, char *argv[])
     }
 
     puts("\t.section .reloc, \"a\", @progbits\n"
-         "\t.balign 4\n"
-         "\t.globl __base_relocs_start, __base_relocs_end\n"
-         "__base_relocs_start:");
+         "\t.balign 4");
 
     for ( i = 0; i < nsec; ++i )
     {
@@ -373,8 +371,6 @@ int main(int argc, char *argv[])
 
     diff_sections(NULL, NULL, NULL, 0, 0, 0, 0);
 
-    puts("__base_relocs_end:");
-
     close(in1);
     close(in2);
 

diff --git a/xen/arch/x86/efi/relocs-dummy.S b/xen/arch/x86/efi/relocs-dummy.S
index d928a82d531d745895382a788703ab47f463383f..b95fa444da9e24b54629c64ac3106037856eb583 100644 (file)
--- a/xen/arch/x86/efi/relocs-dummy.S
+++ b/xen/arch/x86/efi/relocs-dummy.S
@@ -1,10 +1,8 @@
 
        .section .reloc, "a", @progbits
        .balign 4
-GLOBAL(__base_relocs_start)
        .long 0
        .long 8
-GLOBAL(__base_relocs_end)
 
        .globl VIRT_START, ALT_START
        .equ VIRT_START, XEN_VIRT_START

diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 3e29147b6a14d1c7d59cd47fce1d3cd41af2529d..5fadb02b7fae8c6ada7b9234ace01d3e369f32ae 100644 (file)
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -170,18 +170,6 @@ SECTIONS
 #endif
 #endif
 
-/*
- * ELF builds are linked to a fixed virtual address, and in principle
- * shouldn't have a .reloc section.  However, due to the way EFI support is
- * currently implemented, retaining the .reloc section is necessary.
- */
-#if defined(XEN_BUILD_EFI) && !defined(EFI)
-  . = ALIGN(4);
-  DECL_SECTION(.reloc) {
-    *(.reloc)
-  } PHDR(text)
-#endif
-
   _erodata = .;
 
   . = ALIGN(SECTION_ALIGN);
@@ -319,18 +307,27 @@ SECTIONS
   __2M_rwdata_end = .;
 
 #ifdef EFI
-  . = ALIGN(4);
-  DECL_SECTION(.reloc) {
+  .reloc ALIGN(4) : {
+    __base_relocs_start = .;
     *(.reloc)
+    __base_relocs_end = .;
   }
   /* Trick the linker into setting the image size to exactly 16Mb. */
   . = ALIGN(__section_alignment__);
   DECL_SECTION(.pad) {
     . = ALIGN(MB(16));
   }
-#endif
-
-#ifndef XEN_BUILD_EFI
+#elif defined(XEN_BUILD_EFI)
+  /*
+   * Due to the way EFI support is currently implemented, these two symbols
+   * need to be defined.  Their precise values shouldn't matter (the consuming
+   * function doesn't get called), but to be on the safe side both values would
+   * better match.  Of course the need to be reachable by the relocations
+   * referencing them.
+   */
+  PROVIDE(__base_relocs_start = .);
+  PROVIDE(__base_relocs_end = .);
+#else
   efi = .;
 #endif