On Mon, Mar 9, 2015 at 9:11 PM, Andy Lutomirski <l...@amacapital.net> wrote: >> @@ -253,11 +247,13 @@ GLOBAL(system_call_after_swapgs) >> */ >> ENABLE_INTERRUPTS(CLBR_NONE) >> ALLOC_PT_GPREGS_ON_STACK 8 /* +8: space for orig_ax */ >> + movq %rcx,RIP(%rsp) >> + movq PER_CPU_VAR(old_rsp),%rcx >> + movq %r11,EFLAGS(%rsp) >> + movq %rcx,RSP(%rsp) >> + movq_cfi rax,ORIG_RAX >> SAVE_C_REGS_EXCEPT_RAX_RCX_R11 >> movq $-ENOSYS,RAX(%rsp) >> - movq_cfi rax,ORIG_RAX >> - movq %r11,EFLAGS(%rsp) >> - movq %rcx,RIP(%rsp) > > Why the reordering?
No strong reason. iret stack is "above" the rest of pt_regs. This does not matter now, but when/if we convert to PUSHes for register saving, pushes which build iret frame will have to be before "save C-clobbered registers" part, exactly as in this patch. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
