[src/trunk]: src/sys/arch/i386/i386 Map rodata and data+bss independently, an...

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

details:   https://anonhg.NetBSD.org/src/rev/185ba14b5017
branches:  trunk
changeset: 345240:185ba14b5017
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sat May 14 08:49:16 2016 +0000

description:
Map rodata and data+bss independently, and give them R and RW with
fillkpt_nox. The code is exactly the same as amd64's.

diffstat:

 sys/arch/i386/i386/locore.S |  46 ++++++++++++++++++++++++++++++++------------
 1 files changed, 33 insertions(+), 13 deletions(-)

diffs (80 lines):

diff -r b7931d824a36 -r 185ba14b5017 sys/arch/i386/i386/locore.S
--- a/sys/arch/i386/i386/locore.S       Sat May 14 08:39:41 2016 +0000
+++ b/sys/arch/i386/i386/locore.S       Sat May 14 08:49:16 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: locore.S,v 1.120 2016/05/14 08:39:41 maxv Exp $        */
+/*     $NetBSD: locore.S,v 1.121 2016/05/14 08:49:16 maxv Exp $        */
 
 /*
  * Copyright-o-rama!
@@ -128,7 +128,7 @@
  */
 
 #include <machine/asm.h>
-__KERNEL_RCSID(0, "$NetBSD: locore.S,v 1.120 2016/05/14 08:39:41 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: locore.S,v 1.121 2016/05/14 08:49:16 maxv Exp $");
 
 #include "opt_compat_oldboot.h"
 #include "opt_copy_symtab.h"
@@ -684,10 +684,6 @@
         */
        leal    (PROC0_PTP1_OFF)(%esi),%ebx
 
-       /* Compute &__rodata_start - KERNBASE. */
-       movl    $RELOC(__rodata_start),%edx
-       andl    $~PGOFSET,%edx
-
        /* Skip the first MB. */
        movl    $(KERNTEXTOFF - KERNBASE),%eax
        movl    %eax,%ecx
@@ -697,19 +693,43 @@
 #endif
        addl    %ecx,%ebx
 
-       /* Map the kernel text read-only. */
-       movl    %edx,%ecx
+       /* 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 data, BSS, and bootstrap tables read-write. */
-       leal    (PG_V|PG_KW)(%edx),%eax
-       movl    RELOC(tablesize),%ecx
-       addl    %esi,%ecx                       /* end of tables */
-       subl    %edx,%ecx                       /* subtract end of text */
+       /* Map the kernel rodata R. */
+       movl    $RELOC(__rodata_start),%eax
+       movl    $RELOC(__data_start),%ecx
+       subl    %eax,%ecx
+       shrl    $PGSHIFT,%ecx
+       orl     $(PG_V|PG_KR),%eax
+       fillkpt_nox
+
+       /* Map the kernel data+bss RW. */
+       movl    $RELOC(__data_start),%eax
+       movl    $RELOC(__kernel_end),%ecx
+       subl    %eax,%ecx
        shrl    $PGSHIFT,%ecx
+       orl     $(PG_V|PG_KW),%eax
+       fillkpt_nox
+
+       /*
+        * We actually have to be careful here. The memory layout is as
+        * follows:
+        *    +----------+---------------------+------------------+
+        *    | DATA+BSS < [PRELOADED MODULES] | BOOTSTRAP TABLES >
+        *    +----------+---------------------+------------------+
+        * We just map everything from < to > with RWX rights.
+        */
+       movl    $RELOC(__kernel_end),%eax
+       movl    %esi,%ecx               /* start of BOOTSTRAP TABLES */
+       addl    RELOC(tablesize),%ecx   /* end of BOOTSTRAP TABLES */
+       subl    %eax,%ecx               /* subtract end of kernel image */
+       shrl    $PGSHIFT,%ecx
+       orl     $(PG_V|PG_KW),%eax
        fillkpt
 
        /* Map ISA I/O mem (later atdevbase) */