Hello, I have a question about interrupt handling in Linux kernel for x86_64. As we can read in the 64-ia-32-architectures-software-developer-vol-3a-part-1-manual, when an interurpt/exception occurs, the handler's stack contains SS, RSP, RFLAGS, CS, RIP and error code. My question is: does processor push this register on the stack when an interrupt occurs or kernel must push it? In the arch/x86/kernel/entry_64.S we can see following code in the idtentry macro: .ifeq \has_error_code pushq_cfi $-1 .endif where pushq_cfi is: .macro pushq_cfi reg pushq \reg CFI_ADJUST_CFA_OFFSET 8 .endm First of all what does it mean $-1 here? I have write simple assembly program and I see: push 0xffffffffffffffff in the gdb. The second question, if processor pushes error code and other during interrupt why we push it here? Thank you.