[src/trunk]: src/sys/arch/amd64 Map the rodata segment independently on amd64...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/cd93ab7aa4a4
branches:  trunk
changeset: 345194:cd93ab7aa4a4
user:      maxv <maxv%NetBSD.org@localhost>
date:      Thu May 12 07:21:18 2016 +0000

description:
Map the rodata segment independently on amd64, and remove the W permission
on it.

diffstat:

 sys/arch/amd64/amd64/locore.S     |  31 +++++++++++++++++--------------
 sys/arch/amd64/conf/kern.ldscript |   4 +++-
 2 files changed, 20 insertions(+), 15 deletions(-)

diffs (79 lines):

diff -r f717c2e3e8f3 -r cd93ab7aa4a4 sys/arch/amd64/amd64/locore.S
--- a/sys/arch/amd64/amd64/locore.S     Thu May 12 06:57:55 2016 +0000
+++ b/sys/arch/amd64/amd64/locore.S     Thu May 12 07:21:18 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: locore.S,v 1.87 2016/05/12 06:45:16 maxv Exp $ */
+/*     $NetBSD: locore.S,v 1.88 2016/05/12 07:21:18 maxv Exp $ */
 
 /*
  * Copyright-o-rama!
@@ -564,6 +564,8 @@
  *
  * (PROC0 STK + L4 + L3 + L2 + L1) is later referred to as BOOTSTRAP TABLES.
  *
+ * Important note: the kernel segments are properly 4k-aligned
+ * (see kern.ldscript), so there's no need to enforce alignment.
  */
 
        /* Find end of kernel image; brings us on (1). */
@@ -616,16 +618,16 @@
        shrl    $(PGSHIFT-3),%ecx       /* ((n >> PGSHIFT) << 3) for # PDEs */
        addl    %ecx,%ebx
 
-       /*
-        * Compute &__rodata_start - KERNBASE. This can't be > 4G, or we can't
-        * deal with it anyway, since we can't load it in 32 bit mode. So use
-        * the bottom 32 bits.
-        */
-       movl    $RELOC(__rodata_start),%edx
-       andl    $~PGOFSET,%edx
+       /* Map the kernel text RX. */
+       movl    $RELOC(__rodata_start),%ecx
+       subl    %eax,%ecx
+       shrl    $PGSHIFT,%ecx
+       orl     $(PG_V|PG_KR),%eax
+       fillkpt
 
-       /* Map the kernel text read-only. */
-       movl    %edx,%ecx
+       /* Map the kernel rodata ROX. */
+       movl    $RELOC(__rodata_start),%eax
+       movl    $RELOC(__data_start),%ecx
        subl    %eax,%ecx
        shrl    $PGSHIFT,%ecx
        orl     $(PG_V|PG_KR),%eax
@@ -639,11 +641,12 @@
         *  +--------+----------+-------------------+------------------+
         * We just map everything from < to > with RWX rights.
         */
-       leal    (PG_V|PG_KW)(%edx),%eax
-       movl    $TABLESIZE,%ecx
-       addl    %esi,%ecx               /* end of tables */
-       subl    %edx,%ecx               /* subtract end of text */
+       movl    $RELOC(__data_start),%eax
+       movl    %esi,%ecx               /* start of BOOTSTRAP TABLES */
+       addl    $TABLESIZE,%ecx         /* end of BOOTSTRAP TABLES */
+       subl    %eax,%ecx               /* subtract start of DATA */
        shrl    $PGSHIFT,%ecx
+       orl     $(PG_V|PG_KW),%eax
        fillkpt
 
        /* We are on (4). Map ISA I/O mem (later atdevbase) RWX. */
diff -r f717c2e3e8f3 -r cd93ab7aa4a4 sys/arch/amd64/conf/kern.ldscript
--- a/sys/arch/amd64/conf/kern.ldscript Thu May 12 06:57:55 2016 +0000
+++ b/sys/arch/amd64/conf/kern.ldscript Thu May 12 07:21:18 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern.ldscript,v 1.19 2016/05/12 06:45:16 maxv Exp $    */
+/*     $NetBSD: kern.ldscript,v 1.20 2016/05/12 07:21:18 maxv Exp $    */
 
 #include "assym.h"
 
@@ -36,6 +36,8 @@
                *(.rodata.*)
        }
 
+       . = ALIGN(__PAGE_SIZE);
+
        __data_start = . ;
        .data :
        {