How to use RIP Relative Addressing in a 64-bit assembly program?

Question

How do I use RIP Relative Addressing in a Linux assembly program for the AMD64 archtitecture? I am looking for a simple example (a Hello world program) that uses the AMD64 RIP relative adressing mode.

For example the following 64-bit assembly program would work with normal (absolute addressing):

.text     .global _start  _start:     mov $0xd, %rdx      mov $msg, %rsi     pushq $0x1     pop %rax     mov %rax, %rdi     syscall      xor %rdi, %rdi     pushq $0x3c     pop %rax     syscall  .data msg:     .ascii    "Hello world!\n" 

I am guessing that the same program using RIP Relative Addressing would be something like:

.text     .global _start  _start:     mov $0xd, %rdx      mov msg(%rip), %rsi     pushq $0x1     pop %rax     mov %rax, %rdi     syscall      xor %rdi, %rdi     pushq $0x3c     pop %rax     syscall  msg:     .ascii    "Hello world!\n" 

The normal version runs fine when compiled with:

as -o hello.o hello.s && ld -s -o hello hello.o && ./hello 

But I can't get the RIP version working.

Any ideas?

--- edit ----

Stephen Canon's answer makes the RIP version work.

Now when I disassemble the executable of the RIP version I get:

objdump -d hello

0000000000400078 <.text>:   400078: 48 c7 c2 0d 00 00 00  mov    $0xd,%rdx   40007f: 48 8d 35 10 00 00 00  lea    0x10(%rip),%rsi        # 0x400096   400086: 6a 01                 pushq  $0x1   400088: 58                    pop    %rax   400089: 48 89 c7              mov    %rax,%rdi   40008c: 0f 05                 syscall    40008e: 48 31 ff              xor    %rdi,%rdi   400091: 6a 3c                 pushq  $0x3c   400093: 58                    pop    %rax   400094: 0f 05                 syscall    400096: 48                    rex.W   400097: 65                    gs   400098: 6c                    insb   (%dx),%es:(%rdi)   400099: 6c                    insb   (%dx),%es:(%rdi)   40009a: 6f                    outsl  %ds:(%rsi),(%dx)   40009b: 20 77 6f              and    %dh,0x6f(%rdi)   40009e: 72 6c                 jb     0x40010c   4000a0: 64 21 0a              and    %ecx,%fs:(%rdx) 

Which shows what I was trying to accomplish: lea 0x10(%rip),%rsi loads the address 17 bytes after the lea instruction which is address 0x400096 where the Hello world string can be found and thus resulting in position independent code.

Answer 1

I believe that you want to load the address of your string into %rsi; your code attempts to load a quadword from that address rather than the address itself. You want:

lea msg(%rip), %rsi 

if I'm not mistaken. I don't have a linux box to test on, however.