llext: only invalidate instruction cache where needed

When preparing LLEXT ELF sections only invalidate instruction cache
of executable sections. Also skip the step on platforms, managing
cache at the application level.

Signed-off-by: Guennadi Liakhovetski <[email protected]>

Author: lyakh

subsys/llext/llext_link.c

@@ -562,7 +562,9 @@ int llext_link(struct llext_loader *ldr, struct llext *ext, const struct llext_l
 	for (i = 0; i < LLEXT_MEM_COUNT; ++i) {
 		if (ext->mem[i]) {
 			sys_cache_data_flush_range(ext->mem[i], ext->mem_size[i]);
-			sys_cache_instr_invd_range(ext->mem[i], ext->mem_size[i]);
+			if (i == LLEXT_MEM_TEXT && !ldr_parm->pre_located) {
+				sys_cache_instr_invd_range(ext->mem[i], ext->mem_size[i]);
+			}
 		}
 	}
 
@@ -575,7 +577,9 @@ int llext_link(struct llext_loader *ldr, struct llext *ext, const struct llext_l
 				void *base = llext_peek(ldr, shdr->sh_offset);
 
 				sys_cache_data_flush_range(base, shdr->sh_size);
-				sys_cache_instr_invd_range(base, shdr->sh_size);
+				if (shdr->sh_flags & SHF_EXECINSTR && !ldr_parm->pre_located) {
+					sys_cache_instr_invd_range(base, shdr->sh_size);
+				}
 			}
 		}
 	}