[src/trunk]: src/sys/arch/aarch64 set kernel text/rodata readonly when not de...

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

details:   https://anonhg.NetBSD.org/src/rev/8673205d2861
branches:  trunk
changeset: 991877:8673205d2861
user:      ryo <ryo%NetBSD.org@localhost>
date:      Fri Aug 03 16:32:55 2018 +0000

description:
set kernel text/rodata readonly when not defined DDB.
set readonly segment on 2Mbytes aligned. (kernel image is mapped with 2Mbytes L2 block)

diffstat:

 sys/arch/aarch64/aarch64/genassym.cf |   4 ++-
 sys/arch/aarch64/aarch64/locore.S    |  41 +++++++++++++++++++++++++++++++++--
 sys/arch/aarch64/conf/kern.ldscript  |  10 ++++++--
 3 files changed, 48 insertions(+), 7 deletions(-)

diffs (106 lines):

diff -r d117b972ffff -r 8673205d2861 sys/arch/aarch64/aarch64/genassym.cf
--- a/sys/arch/aarch64/aarch64/genassym.cf      Fri Aug 03 16:31:04 2018 +0000
+++ b/sys/arch/aarch64/aarch64/genassym.cf      Fri Aug 03 16:32:55 2018 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: genassym.cf,v 1.5 2018/07/17 10:01:59 ryo Exp $
+# $NetBSD: genassym.cf,v 1.6 2018/08/03 16:32:55 ryo Exp $
 #-
 # Copyright (c) 2014 The NetBSD Foundation, Inc.
 # All rights reserved.
@@ -120,6 +120,8 @@
 define LX_BLKPAG_UXN           LX_BLKPAG_UXN
 define LX_BLKPAG_PXN           LX_BLKPAG_PXN
 define LX_BLKPAG_AF            LX_BLKPAG_AF
+define LX_BLKPAG_AP            LX_BLKPAG_AP
+define LX_BLKPAG_AP_RO         LX_BLKPAG_AP_RO
 define LX_BLKPAG_AP_RW         LX_BLKPAG_AP_RW
 define LX_BLKPAG_SH_IS         LX_BLKPAG_SH_IS
 define LX_BLKPAG_ATTR_INDX_0   LX_BLKPAG_ATTR_INDX_0
diff -r d117b972ffff -r 8673205d2861 sys/arch/aarch64/aarch64/locore.S
--- a/sys/arch/aarch64/aarch64/locore.S Fri Aug 03 16:31:04 2018 +0000
+++ b/sys/arch/aarch64/aarch64/locore.S Fri Aug 03 16:32:55 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: locore.S,v 1.13 2018/07/17 18:08:36 christos Exp $     */
+/*     $NetBSD: locore.S,v 1.14 2018/08/03 16:32:55 ryo Exp $  */
 
 /*
  * Copyright (c) 2017 Ryo Shimizu <ryo%nerv.org@localhost>
@@ -35,7 +35,7 @@
 #include <aarch64/hypervisor.h>
 #include "assym.h"
 
-RCSID("$NetBSD: locore.S,v 1.13 2018/07/17 18:08:36 christos Exp $")
+RCSID("$NetBSD: locore.S,v 1.14 2018/08/03 16:32:55 ryo Exp $")
 
 /* #define DEBUG_LOCORE */
 /* #define DEBUG_MMU */
@@ -650,9 +650,44 @@
        lsr     x4, x4, #L2_SHIFT
        bl      l2_setblocks
 
+#ifndef DDB
+       /* map READONLY from VM_MIN_KERNEL_ADDRESS to __data_start */
+       VERBOSE("Set kernel text/rodata READONLY\r\n")
+       ldr     x3, =__data_start
+       ands    x0, x3, #(L2_SIZE - 1)
+       beq     1f
+       ldr     x1, =_erodata
+       and     x1, x1, #L2_ADDR_BITS   /* _erodata & L2_ADDR_BIT */
+       and     x0, x3, #L2_ADDR_BITS   /* __data_start & L2_ADDR_BIT */
+       cmp     x0, x1
+       bne     1f
+       /* __data_start and _erodata are in same L2 block */
+       PRINT("Warning: data section not aligned on size of L2 block\r\n")
+1:
+       /* x3 = l2pde_index(__data_start) */
+       and     x3, x3, #L2_ADDR_BITS
+       lsr     x3, x3, #L2_SHIFT
+
+       /* x2 = l2pde_inex(VM_MIN_KERNEL_ADDRESS) */
+       mov     x2, #VM_MIN_KERNEL_ADDRESS
+       and     x2, x2, #L2_ADDR_BITS
+       lsr     x2, x2, #L2_SHIFT
+
+       ADDR    x1, ttbr1_l2table_kva
+       b       9f
+1:
+       ldr     x0, [x1, x2, lsl #3]    /* x0 = l2table[x2] */
+       and     x0, x0, #~LX_BLKPAG_AP
+       orr     x0, x0, #LX_BLKPAG_AP_RO
+       str     x0, [x1, x2, lsl #3]    /* l2table[x2] = x0 */
+       add     x2, x2, #1
+9:
+       cmp     x2, x3
+       blo     1b
+#endif
+
        VERBOSE("Creating devmap tables\r\n")
        /* devmap=PA table for L1 */
-nop
        ADDR    x0, ttbr1_l1table_kva
        ldr     x1, .L_devmap_addr
        ADDR    x2, ttbr1_l2table_devmap
diff -r d117b972ffff -r 8673205d2861 sys/arch/aarch64/conf/kern.ldscript
--- a/sys/arch/aarch64/conf/kern.ldscript       Fri Aug 03 16:31:04 2018 +0000
+++ b/sys/arch/aarch64/conf/kern.ldscript       Fri Aug 03 16:32:55 2018 +0000
@@ -1,3 +1,5 @@
+#include "assym.h"
+
 /* Default linker script, for normal executables */
 OUTPUT_FORMAT("elf64-littleaarch64", "elf64-bigaarch64",
              "elf64-littleaarch64")
@@ -30,9 +32,11 @@
   PROVIDE (__etext = .);
   PROVIDE (_etext = .);
   PROVIDE (etext = .);
-  /* Adjust the address for the data segment.  We want to adjust up to
-     the same address within the page on the next page up.  */
-  . = ALIGN (CONSTANT (MAXPAGESIZE)) - ((CONSTANT (MAXPAGESIZE) - .) & (CONSTANT (MAXPAGESIZE) - 1)); . = DATA_SEGMENT_ALIGN (CONSTANT (MAXPAGESIZE), CONSTANT (COMMONPAGESIZE));
+  /* Adjust the address for the data segment. Move .data to the next L2 block,
+     and .text and .rodata will be set readonly if needed. */
+  PROVIDE (_erodata = .);
+  . = ALIGN (L2_SIZE);
+  . = DATA_SEGMENT_ALIGN (CONSTANT (MAXPAGESIZE), CONSTANT (COMMONPAGESIZE));
   /* Exception handling  */
   .eh_frame       : ONLY_IF_RW { KEEP (*(.eh_frame)) }
   .gcc_except_table   : ONLY_IF_RW { *(.gcc_except_table .gcc_except_table.*) }