1 /* Add SORT_BY_ALIGNMENT to linker script (found in busybox_unstripped.out):
2 ## .rodata : { *(.rodata SORT_BY_ALIGNMENT(.rodata.*) .gnu.linkonce.r.*) }
3 ## .data : { *(.data SORT_BY_ALIGNMENT(.data.*) .gnu.linkonce.d.*) }
4 ## .bss : { *(.bss SORT_BY_ALIGNMENT(.bss.*) .gnu.linkonce.b.*) }
5 ## This will eliminate most of the padding (~3kb).
6 ## Hmm, "ld --sort-section alignment" should do it too.
8 ## There is a ld hack which is meant to decrease disk usage
9 ## at the cost of more RAM usage (??!!) in standard ld script:
10 ## . = ALIGN (0x1000) - ((0x1000 - .) & (0x1000 - 1)); . = DATA_SEGMENT_ALIGN (0x1000, 0x1000);
12 ## . = ALIGN (0x1000); . = DATA_SEGMENT_ALIGN (0x1000, 0x1000);
13 ## to unconditionally align .data to the next page boundary,
14 ## instead of "next page, plus current offset in this page"
17 /* To reduce the number of VMAs each bbox process has,
18 ## move *(.bss SORT_BY_ALIGNMENT(.bss.*) ...)
19 ## part from .bss : {...} block to .data : { ... } block.
20 ## (This usually increases .data section by only one page).
23 ## text data bss dec hex filename
24 ## 1050792 560 7580 1058932 102874 busybox.bss
25 ## 1050792 8149 0 1058941 10287d busybox.nobss
27 ## $ exec busybox.bss pmap $$
28 ## 0000000008048000 1028K r-xp /path/to/busybox.bss
29 ## 0000000008149000 8K rw-p /path/to/busybox.bss
30 ## 000000000814b000 4K rw-p [ anon ] <---- this VMA is eliminated
31 ## 00000000085f5000 4K ---p [heap]
32 ## 00000000085f6000 4K rw-p [heap]
33 ## 00000000f7778000 8K rw-p [ anon ]
34 ## 00000000f777a000 12K r--p [vvar]
35 ## 00000000f777d000 8K r-xp [vdso]
36 ## 00000000ff7e9000 132K rw-p [stack]
38 ## $ exec busybox.nobss pmap $$
39 ## 0000000008048000 1028K r-xp /path/to/busybox.nobss
40 ## 0000000008149000 12K rw-p /path/to/busybox.nobss
41 ## 00000000086f0000 4K ---p [heap]
42 ## 00000000086f1000 4K rw-p [heap]
43 ## 00000000f7783000 8K rw-p [ anon ]
44 ## 00000000f7785000 12K r--p [vvar]
45 ## 00000000f7788000 8K r-xp [vdso]
46 ## 00000000ffac0000 132K rw-p [stack]