HBBL could be assembled using linker script rather than cat and dd

[ghost]

The Hostboot Boot Loader image is made up of a few things:

1. The Host Boot Boot Loader itself
2. The securerom image (the size of the image and then the image itself)
3. the hash of the hardware keys in the last 64 bytes of the image

This is currently constructed first using the linker script src/bootloader.ld for step 1, and subsequently manipulated in genPnorImages.pl to do 2 and 3.

There's no reason 2 and 3 couldn't be done by the linker script, which would give us the benefit of being able to catch HBBL and/or securerom growing beyond the maximum allowed HBBL size (which is restricted due to the size of the SBE SEEPROM)

[ghost]

Something like this for the linker script

--- a/src/bootloader.ld
+++ b/src/bootloader.ld
@@ -27,6 +27,8 @@ base_load_address = 0x00000000;
 sbe_hb_structures = 0x00000004;
 /* Text section offset = 12KB (space reserved for exception vectors)      */
 text_load_address = 0x00003000;
+max_hbbl_size = 0x5000;
+hw_key_hash_size = 64;
 
 SECTIONS
 {
@@ -92,6 +94,23 @@ SECTIONS
         *(.dtors)
         *(.interp)
     }
+
+    . = ALIGN(0x8);
+    QUAD(end_securerom - start_securerom);
+
+    .securerom : {
+        start_securerom = .;
+        KEEP(*(.securerom))
+        end_securerom = .;
+    }
+
+    . = max_hbbl_size + text_load_address - hw_key_hash_size;
+    .hwkeyhash : {
+        start_hwkeyhash = .;
+       KEEP(*(.hwkeyhash))
+       end_hwkeyhash = .;
+    }
+    . = max_hbbl_size + text_load_address;
 }

and then you just need to link in two files like this:

securerom.S

	.section ".securerom","a"
	.incbin "securerom.bin"

and
hwkeyhash.S

	.section ".hwkeyhash","a"
	.incbin "hwkeyhash.bin"

the reason this is currently tricky is that Hostboot makefiles don't follow the advice "Recursive Make Considered Harmful" and thus things get weird.

[ghost]

This would let us remove dd and cat invocations in src/build/mkrules/hbfw/img/makefile as well as in genPnorImages.pl and have a flashable hbbl.bin image come directly out of the link operation.