From: Kevin O'Connor <kevin@koconnor.net>
Date: Sat, 20 Feb 2016 02:34:16 +0000 (-0500)
Subject: build: fix .text section address alignment
X-Git-Tag: rel-1.10.0~65
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=3910de0dee216d5b5bf23cfa29bfc80d082b2ee7;p=seabios.git

build: fix .text section address alignment

Some linkers verify that sections have a start address that is aligned
with the minimum alignment of that section.  Add extra padding to the
".text" section to ensure it is always aligned with the maximum
alignment of any section placed in ".text".

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reported by: Ed Maste <emaste@FreeBSD.org>
---

diff --git a/scripts/layoutrom.py b/scripts/layoutrom.py
index b976fb0..6616721 100755
--- a/scripts/layoutrom.py
+++ b/scripts/layoutrom.py
@@ -34,18 +34,22 @@ COMMONTRAILER = """
 # Determine section locations
 ######################################################################
 
-# Align 'pos' to 'alignbytes' offset
+# Align 'pos' up to 'alignbytes' offset
 def alignpos(pos, alignbytes):
     mask = alignbytes - 1
     return (pos + mask) & ~mask
 
+# Align 'pos' down to 'alignbytes' offset
+def aligndown(pos, alignbytes):
+    mask = alignbytes - 1
+    return pos & ~mask
+
 # Determine the final addresses for a list of sections that end at an
 # address.
 def setSectionsStart(sections, endaddr, minalign=1, segoffset=0):
     totspace = 0
     for section in sections:
-        if section.align > minalign:
-            minalign = section.align
+        minalign = max(minalign, section.align)
         totspace = alignpos(totspace, section.align) + section.size
     startaddr = int((endaddr - totspace) / minalign) * minalign
     curaddr = startaddr
@@ -269,7 +273,7 @@ def doLayout(sections, config, genreloc):
         final_sec32low_end = BUILD_LOWRAM_END
         zonelow_base = final_sec32low_end - 64*1024
     relocdelta = final_sec32low_end - sec32low_end
-    li.sec32low_start, li.sec32low_align = setSectionsStart(
+    li.sec32low_start, sec32low_align = setSectionsStart(
         sections32low, sec32low_end, 16
         , segoffset=zonelow_base - relocdelta)
     li.sec32low_end = sec32low_end
@@ -405,6 +409,8 @@ def writeLinkerScripts(li, out16, out32seg, out32flat):
     if li.config.get('CONFIG_MULTIBOOT'):
         multiboot_header = "LONG(0x1BADB002) LONG(0) LONG(-0x1BADB002)"
         sec32all_start -= 3 * 4
+    sec32all_align = max([section.align for section in li.sections])
+    sec32all_start = aligndown(sec32all_start, sec32all_align)
     out += outXRefs(filesections32flat, exportsyms=[li.entrysym]) + """
     _reloc_min_align = 0x%x ;
     zonefseg_start = 0x%x ;