Date: Mon, 8 Oct 2001 08:30:37 -0700 From: Mark Peek <mark@whistle.com> To: freebsd-hackers@FreeBSD.ORG Subject: Change to ldscript.i386 Message-ID: <p05101000b7e77470ca47@[207.76.207.129]>
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I made a change to page align the data segment on the powerpc port and I
noticed something strange with the i386 alignment. The data section appears
to be wasting space by aligning to the same address (offset) in the next
page rather than to the next page boundary. Below is the patch and a
before/after objdump of the kernel headers. The difference isn't that big
(no more than 4K) but my patch seems more correct.
Am I missing any reason why it was done this way? If not, I'll apply the
patch to -current.
Thanks,
Mark
-------------
Index: ldscript.i386
===================================================================
RCS file: /cvs/freebsd/src/sys/conf/ldscript.i386,v
retrieving revision 1.5
diff -u -u -r1.5 ldscript.i386
--- ldscript.i386 2001/09/18 01:12:43 1.5
+++ ldscript.i386 2001/09/24 22:34:02
@@ -55,9 +55,8 @@
.fini : { *(.fini) } =0x9090
.rodata : { *(.rodata) *(.gnu.linkonce.r*) }
.rodata1 : { *(.rodata1) }
- /* 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(0x1000) + (. & (0x1000 - 1)) ;
+ /* Adjust the address for the data segment to the next page up. */
+ . = ((. + 0x1000) & ~(0x1000 - 1));
.data :
{
*(.data)
Before patch:
kernel: file format elf32-i386
Sections:
Idx Name Size VMA LMA File off Algn
0 .interp 0000000d c01000d4 c01000d4 000000d4 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
1 .hash 000095f0 c01000e4 c01000e4 000000e4 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
2 .dynsym 00015770 c01096d4 c01096d4 000096d4 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
3 .dynstr 00014352 c011ee44 c011ee44 0001ee44 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
4 .text 00207448 c01331a0 c01331a0 000331a0 2**4
CONTENTS, ALLOC, LOAD, READONLY, CODE
5 .rodata 0005bfa0 c033a600 c033a600 0023a600 2**5
CONTENTS, ALLOC, LOAD, READONLY, DATA
6 set_modmetadata_set 0000050c c03965a0 c03965a0 002965a0 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
7 set_sysinit_set 00000894 c0396aac c0396aac 00296aac 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
8 set_sysctl_set 00000b44 c0397340 c0397340 00297340 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
9 set_db_cmd_set 00000004 c0397e84 c0397e84 00297e84 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
10 set_db_show_cmd_set 00000044 c0397e88 c0397e88 00297e88 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
11 set_sysuninit_set 00000338 c0397ecc c0397ecc 00297ecc 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
12 set_kbddriver_set 00000008 c0398204 c0398204 00298204 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
13 set_cons_set 0000000c c039820c c039820c 0029820c 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
14 set_videodriver_set 00000010 c0398218 c0398218 00298218 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
15 set_scterm_set 00000004 c0398228 c0398228 00298228 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
16 set_scrndr_set 0000001c c039822c c039822c 0029822c 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
17 set_vga_set 0000001c c0398248 c0398248 00298248 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
18 .data 00049d20 c0399280 c0399280 00298280 2**5
CONTENTS, ALLOC, LOAD, DATA
19 .got 0000000c c03e2fa0 c03e2fa0 002e1fa0 2**2
CONTENTS, ALLOC, LOAD, DATA
20 .dynamic 00000040 c03e2fac c03e2fac 002e1fac 2**2
CONTENTS, ALLOC, LOAD, DATA
21 .bss 00035534 c03e3000 c03e3000 002e2000 2**5
ALLOC
22 .comment 00008caf 00000000 00000000 002e2000 2**0
CONTENTS, READONLY
23 .note 00003688 00000000 00000000 002eacaf 2**0
CONTENTS, READONLY
After patch:
kernel: file format elf32-i386
Sections:
Idx Name Size VMA LMA File off Algn
0 .interp 0000000d c01000d4 c01000d4 000000d4 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
1 .hash 000095f0 c01000e4 c01000e4 000000e4 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
2 .dynsym 00015770 c01096d4 c01096d4 000096d4 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
3 .dynstr 00014352 c011ee44 c011ee44 0001ee44 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
4 .text 00207448 c01331a0 c01331a0 000331a0 2**4
CONTENTS, ALLOC, LOAD, READONLY, CODE
5 .rodata 0005bfa0 c033a600 c033a600 0023a600 2**5
CONTENTS, ALLOC, LOAD, READONLY, DATA
6 set_modmetadata_set 0000050c c03965a0 c03965a0 002965a0 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
7 set_sysinit_set 00000894 c0396aac c0396aac 00296aac 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
8 set_sysctl_set 00000b44 c0397340 c0397340 00297340 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
9 set_db_cmd_set 00000004 c0397e84 c0397e84 00297e84 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
10 set_db_show_cmd_set 00000044 c0397e88 c0397e88 00297e88 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
11 set_sysuninit_set 00000338 c0397ecc c0397ecc 00297ecc 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
12 set_kbddriver_set 00000008 c0398204 c0398204 00298204 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
13 set_cons_set 0000000c c039820c c039820c 0029820c 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
14 set_videodriver_set 00000010 c0398218 c0398218 00298218 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
15 set_scterm_set 00000004 c0398228 c0398228 00298228 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
16 set_scrndr_set 0000001c c039822c c039822c 0029822c 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
17 set_vga_set 0000001c c0398248 c0398248 00298248 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
18 .data 00049d20 c0399000 c0399000 00299000 2**5
CONTENTS, ALLOC, LOAD, DATA
19 .got 0000000c c03e2d20 c03e2d20 002e2d20 2**2
CONTENTS, ALLOC, LOAD, DATA
20 .dynamic 00000040 c03e2d2c c03e2d2c 002e2d2c 2**2
CONTENTS, ALLOC, LOAD, DATA
21 .bss 00035534 c03e2d80 c03e2d80 002e2d80 2**5
ALLOC
22 .comment 00008caf 00000000 00000000 002e2d80 2**0
CONTENTS, READONLY
23 .note 00003688 00000000 00000000 002eba2f 2**0
CONTENTS, READONLY
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