Re: [patch V4 part 3 09/29] x86/entry/32: Provide macro to emit IDT entry stubs

From: Mathieu Desnoyers
Date: Wed May 13 2020 - 21:44:44 EST


----- On May 5, 2020, at 9:44 AM, Thomas Gleixner tglx@xxxxxxxxxxxxx wrote:

[...]

> +.macro idtentry vector asmsym cfunc has_error_code:req sane=0
> +SYM_CODE_START(\asmsym)
> + ASM_CLAC
> + cld

Looking at the various interrupt and trap entry points for 32 and 64-bit
x86, I notice a lack of consistency in use of the following instruction
sequence at the asm entry point:

- ASM_CLAC,
- cld (clear direction flag).

Are they always needed, or only for interrupt handlers ?

Thanks,

Mathieu

--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com