Add support for 64-bit PowerPC kernels to be directly loaded by kexec, which

is used as the bootloader on a number of PPC64 platforms. This involves the
following pieces:
- Making the first instruction a valid kernel entry point, since kexec
  ignores the ELF entry value. This requires a separate section and linker
  magic to prevent the linker from filling the beginning of the section
  with stubs.
- Adding an entry point at 0x60 past the first instruction for systems
  lacking firmware CPU shutdown support (notably PS3).
- Linker script changes to support the above.

MFC after:	1 month

1 files changed, 8 insertions, 1 deletions

diff --git a/sys/conf/ldscript.powerpc64 b/sys/conf/ldscript.powerpc64
index 82836699456e..025c65451972 100644
--- a/sys/conf/ldscript.powerpc64
+++ b/sys/conf/ldscript.powerpc64
@@ -8,8 +8,12 @@ SEARCH_DIR(/usr/lib);
 PROVIDE (__stack = 0);
 SECTIONS
 {
-  /* Read-only sections, merged into text segment: */
 
+  /* Low-address wrapper for bootloaders (kexec/kboot) that can't parse ELF */
+  . = kernbase - 0x100;
+  .kboot : { *(.text.kboot) }
+
+  /* Read-only sections, merged into text segment: */
   . = kernbase;
   PROVIDE (begin = .);
 
@@ -28,6 +32,9 @@ SECTIONS
   .interpX    : { *(.interp) 	} : NONE
   /DISCARD/   : { *(.interp)	} 
 
+  /* Also delete notes */
+  /DISCARD/   : { *(.note.*)	} 
+
   .hash          : { *(.hash)		}
   .dynsym        : { *(.dynsym)		}
   .dynstr        : { *(.dynstr)		}