My machine’s architecture is x86_64 and I’ve cross-compiled arm64 assembly (from here) into an executable. However the binary is still runnable on my machine… how?
Here are the outputs to the following commands:
$ uname -r
6.2.12-100.fc36.x86_64
$ file hello
hello: ELF 64-bit LSB executable, ARM aarch64, version 1 (SYSV), statically linked, stripped
$ ./hello
Hello, ARM64
$ qemu-aarch64-static hello
Hello, ARM64
$ qemu-x86_64-static hello
qemu-x86_64-static: hello: Invalid ELF image for this architecture
$ readelf -a hello
ELF Header:
Magic: 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
Class: ELF64
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: AArch64
Version: 0x1
Entry point address: 0x4000b0
Start of program headers: 64 (bytes into file)
Start of section headers: 264 (bytes into file)
Flags: 0x0
Size of this header: 64 (bytes)
Size of program headers: 56 (bytes)
Number of program headers: 2
Size of section headers: 64 (bytes)
Number of section headers: 4
Section header string table index: 3
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
[ 0] NULL 0000000000000000 00000000
0000000000000000 0000000000000000 0 0 0
[ 1] .text PROGBITS 00000000004000b0 000000b0
0000000000000030 0000000000000000 AX 0 0 8
[ 2] .data PROGBITS 00000000004100e0 000000e0
000000000000000d 0000000000000000 WA 0 0 1
[ 3] .shstrtab STRTAB 0000000000000000 000000ed
0000000000000017 0000000000000000 0 0 1
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
L (link order), O (extra OS processing required), G (group), T (TLS),
C (compressed), x (unknown), o (OS specific), E (exclude),
D (mbind), p (processor specific)
There are no section groups in this file.
Program Headers:
Type Offset VirtAddr PhysAddr
FileSiz MemSiz Flags Align
LOAD 0x0000000000000000 0x0000000000400000 0x0000000000400000
0x00000000000000e0 0x00000000000000e0 R E 0x10000
LOAD 0x00000000000000e0 0x00000000004100e0 0x00000000004100e0
0x000000000000000d 0x000000000000000d RW 0x10000
Section to Segment mapping:
Segment Sections...
00 .text
01 .data
There is no dynamic section in this file.
There are no relocations in this file.
The decoding of unwind sections for machine type AArch64 is not currently supported.
No version information found in this file.