If you create perfectly valid elf file which doesn't have section .text, all symbols in symbol table have wrong section ... including symbol _start, which means program resulting from link will be unusable. Of course, in most cases there will be NO program resulting from link, because ld segfaults on object file with references to such symbols.
example code:
1) linkable
SECTION .hkcode progbits alloc exec write align=16
_start:
global _start
mov eax,1
int 80h
section .data
global entr
entr db 0Ah
2) unlinkable
SECTION .hkcode progbits alloc exec write align=16
_start:
global _start
mov eax,1
int 80h
section data
text db 'Hello from yasm',0Ah,0
section .hkcode
mov esi,text
