Re: [PATCH 22/43] x86/mm/kaiser: Prepare assembly for entry/exit CR3 switching

[Thomas Gleixner]

On Fri, 24 Nov 2017, Ingo Molnar wrote:
> @@ -1288,6 +1308,8 @@ ENTRY(error_entry)
>  	 * from user mode due to an IRET fault.
>  	 */
>  	SWAPGS
> +	/* We have user CR3.  Change to kernel CR3. */
> +	SWITCH_TO_KERNEL_CR3 scratch_reg=%rax
>  
>  .Lerror_entry_from_usermode_after_swapgs:
>  	/* Put us onto the real thread stack. */
> @@ -1333,6 +1355,7 @@ ENTRY(error_entry)
>  	 * gsbase and proceed.  We'll fix up the exception and land in
>  	 * .Lgs_change's error handler with kernel gsbase.
>  	 */
> +	SWITCH_TO_KERNEL_CR3 scratch_reg=%rax
>  	SWAPGS

This is wrong. SWAPGS needs to come first.

Thanks,

	tglx