ref: 74d91a0021de012908cfdb35fb61a1473a376130
dir: /rt/start-openbsd.s/
.section ".note.openbsd.ident", "a" .p2align 2 .long 8 .long 4 .long 1 .ascii "OpenBSD\0" .long 0 .p2align 2 .data /* sys.__cenvp : byte## */ .globl sys$__cenvp sys$__cenvp: .quad 0 .globl thread$__tls thread$__tls: .fill 88 /* sizeof(tlshdr) + (8 * sizeof(void#)) = 24 + 64 */ .text /* * The entry point for the whole program. * This is called by the OS. In order, it: * - Sets up all argc entries as slices * - Converts argc/argv to a slice * - Stashes a raw envp copy in __cenvp (for syscalls to use) * - Sets up thread local storage for the main thread * - Calls main() */ .globl _start _start: movq %rsp,%rbp andq $-16,%rsp /* align the stack pointer */ /* load argc, argv, envp from stack */ movq (%rbp),%rax /* argc */ leaq 8(%rbp),%rbx /* argv */ leaq 16(%rbp,%rax,8),%rcx /* envp = argv + 8*argc + 8 */ /* store envp for some syscalls to use without converting */ movq %rcx,sys$__cenvp(%rip) /* stack allocate sizeof(byte[:])*argc */ imulq $16,%rax,%rdx subq %rdx,%rsp movq %rsp,%rcx /* args[:] */ /* convert argc, argv to byte[:][:] for args. */ pushq %rax pushq %rcx call cvt /* set up the intial tls region for the main thread */ movq $329,%rax /* Sys__set_tcb */ leaq thread$__tls(%rip),%rdi syscall xorq %rbp,%rbp /* we're done startup, and we kind of want to call kbind here, but this breaks when we dynamically link in libc. */ call __init__ call main call __fini__ /* exit(0) */ xorq %rdi,%rdi movq $1,%rax syscall /* * provide __guard_local for if we are * linking against libc */ .section ".openbsd.randomdata", "aw" .global __guard_local .hidden __guard_local .type __guard_local, "object" .p2align 3 __guard_local: .quad 0 .size __guard_local, 8 .section ".note.openbsd.ident", "a" .p2align 2 .long 8 .long 4 .long 1 .ascii "OpenBSD\0" .long 0 .p2align 2