[Xen-devel] [PATCH 3/4] x86/linker: add a reloc section to ELF binary

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

If the hypervisor has been built with EFI support (ie: multiboot2).
This allows to position the .reloc section correctly in the output
binary, or else the linker might place .reloc before the .text
section.

Note that the .reloc section is moved before .bss for two reasons: in
order for the resulting binary to not contain any section with data
after .bss, so that the file size can be smaller than the loaded
memory size, and because the data it contains is read-only, so it
belongs with the other sections containing read-only data.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Wei Liu <wl@xxxxxxx>
---
 xen/arch/x86/xen.lds.S | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 98a99444c2..82103ef1da 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -175,6 +175,14 @@ SECTIONS
   } :text
 #endif
 #endif
+
+#ifdef XEN_BUILD_EFI
+  . = ALIGN(4);
+  DECL_SECTION(.reloc) {
+    *(.reloc)
+  } :text
+#endif
+
   _erodata = .;
 
   . = ALIGN(SECTION_ALIGN);
@@ -297,10 +305,6 @@ SECTIONS
   __2M_rwdata_end = .;
 
 #ifdef EFI
-  . = ALIGN(4);
-  DECL_SECTION(.reloc) {
-    *(.reloc)
-  } :text
   /* Trick the linker into setting the image size to exactly 16Mb. */
   . = ALIGN(__section_alignment__);
   DECL_SECTION(.pad) {
-- 
2.20.1 (Apple Git-117)


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