com32: make com32 modules self-relocating (COM32R)

Introduce a new "COM32R" format, which is exactly like COM32 except
that they contain position-independent code.  Therefore, the core can
load them at any sufficiently aligned address; by protocol select 4K
as the alignment.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 41 insertions, 24 deletions

diff --git a/com32/lib/com32.ld b/com32/lib/com32.ld
index 36d5b6ed..41e88da4 100644
--- a/com32/lib/com32.ld
+++ b/com32/lib/com32.ld
@@ -11,7 +11,7 @@ ENTRY(_start)
 SECTIONS
 {
   /* Read-only sections, merged into text segment: */
-  . = 0x101000;
+  . = 0;
   PROVIDE (__executable_start = .);
 
   .init           :
@@ -39,29 +39,44 @@ SECTIONS
      the linker would then create the section even if it turns out to
      be empty, which isn't pretty.  */
   . = ALIGN(4);
-  PROVIDE (__preinit_array_start = .);
-  .preinit_array     : { *(.preinit_array) }
-  PROVIDE (__preinit_array_end = .);
-  PROVIDE (__init_array_start = .);
-  .init_array     : { *(.init_array) }
-  PROVIDE (__init_array_end = .);
-  PROVIDE (__fini_array_start = .);
-  .fini_array     : { *(.fini_array) }
-  PROVIDE (__fini_array_end = .);
-  PROVIDE (__ctors_start = .);
-  .ctors          :
-  {
+  .preinit_array     : {
+    PROVIDE (__preinit_array_start = .);
+    *(.preinit_array)
+    PROVIDE (__preinit_array_end = .);
+  }
+  .init_array     : {
+    PROVIDE (__init_array_start = .);
+    *(.init_array)
+    PROVIDE (__init_array_end = .);
+  }
+  .fini_array     : {
+    PROVIDE (__fini_array_start = .);
+    *(.fini_array)
+    PROVIDE (__fini_array_end = .);
+  }
+  .ctors          : {
+    PROVIDE (__ctors_start = .);
     KEEP (*(SORT(.ctors.*)))
     KEEP (*(.ctors))
+    PROVIDE (__ctors_end = .);
   }
-  PROVIDE (__ctors_end = .);
-  PROVIDE (__dtors_start = .);
-  .dtors          :
-  {
+  .dtors          : {
+    PROVIDE (__dtors_start = .);
     KEEP (*(SORT(.dtors.*)))
     KEEP (*(.dtors))
+    PROVIDE (__dtors_end = .);
+  }
+
+  .got            : {
+    PROVIDE (__got_start = .);
+    KEEP (*(.got))
+    PROVIDE (__got_end = .);
+  }
+  .got.plt        : {
+    PROVIDE (__got_plt_start = .);
+    KEEP (*(.got.plt))
+    PROVIDE (__got_plt_end = .);
   }
-  PROVIDE (__dtors_end = .);
 
   /* Adjust the address for the data segment.  Avoid mixing code and
      data within same 128-byte chunk. */
@@ -69,12 +84,14 @@ SECTIONS
 
   .data           :
   {
-    *(.data .data.* .gnu.linkonce.d.*)
+    _sdata = .;
+    KEEP(*(.data .data.* .gnu.linkonce.d.*))
     SORT(CONSTRUCTORS)
+    *(.data1)
+    . = ALIGN(4);
+    _edata = .;
   }
-  .data1          : { *(.data1) }
-  _edata = .;
-  PROVIDE (edata = .);
+
   __bss_start = .;
   .bss            :
   {
@@ -84,9 +101,9 @@ SECTIONS
    /* Align here to ensure that the .bss section occupies space up to
       _end.  Align after .bss to ensure correct alignment even if the
       .bss section disappears because there are no input sections.  */
-   . = ALIGN(32 / 8);
+   . = ALIGN(4);
   }
-  . = ALIGN(32 / 8);
+  . = ALIGN(4);
   _end = .;
   PROVIDE (end = .);