diff options
| -rw-r--r-- | arch/x86/machine/tcb_asm.S | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/machine/tcb_asm.S b/arch/x86/machine/tcb_asm.S index 7c9140f0..a6e31da5 100644 --- a/arch/x86/machine/tcb_asm.S +++ b/arch/x86/machine/tcb_asm.S @@ -47,8 +47,16 @@ ASM_END(tcb_context_load) ASM_ENTRY(tcb_start) popq %rdi /* load function */ popq %rsi /* load argument */ - call thread_main /* use the call instruction to start - a clean stack trace */ + + /* + * Use the call instruction to start a clean stack trace. + * + * Note that, on amd64, the stack must be 16-byte before the call + * instruction, so that "$(rsp + 8) is a multiple is always a multiple + * of 16 when control is transferred to the function entry point", + * which is another reason to use call instead of a bare jump. + */ + call thread_main /* Never reached */ nop /* make the return address point to an instruction |