| Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame] | 1 | /* |
| 2 | initramfs_data includes the compressed binary that is the |
| 3 | filesystem used for early user space. |
| 4 | Note: Older versions of "as" (prior to binutils 2.11.90.0.23 |
| 5 | released on 2001-07-14) dit not support .incbin. |
| 6 | If you are forced to use older binutils than that then the |
| 7 | following trick can be applied to create the resulting binary: |
| 8 | |
| 9 | |
| 10 | ld -m elf_i386 --format binary --oformat elf32-i386 -r \ |
| 11 | -T initramfs_data.scr initramfs_data.cpio.gz -o initramfs_data.o |
| 12 | ld -m elf_i386 -r -o built-in.o initramfs_data.o |
| 13 | |
| 14 | For including the .init.ramfs sections, see include/asm-generic/vmlinux.lds. |
| 15 | |
| 16 | The above example is for i386 - the parameters vary from architectures. |
| 17 | Eventually look up LDFLAGS_BLOB in an older version of the |
| 18 | arch/$(ARCH)/Makefile to see the flags used before .incbin was introduced. |
| 19 | |
| 20 | Using .incbin has the advantage over ld that the correct flags are set |
| 21 | in the ELF header, as required by certain architectures. |
| 22 | */ |
| 23 | |
| 24 | #include <linux/stringify.h> |
| 25 | #include <asm-generic/vmlinux.lds.h> |
| 26 | |
| 27 | .section .init.ramfs,"a" |
| 28 | __irf_start: |
| 29 | .incbin __stringify(INITRAMFS_IMAGE) |
| 30 | __irf_end: |
| 31 | .section .init.ramfs.info,"a" |
| 32 | .globl VMLINUX_SYMBOL(__initramfs_size) |
| 33 | VMLINUX_SYMBOL(__initramfs_size): |
| 34 | #ifdef CONFIG_64BIT |
| 35 | .quad __irf_end - __irf_start |
| 36 | #else |
| 37 | .long __irf_end - __irf_start |
| 38 | #endif |