Re: [PATCH v6 1/2] xen/riscv: introduce early_printk basic stuff

[Julien Grall <julien@xxxxxxx>]

Hi,

On 27/01/2023 11:15, Oleksii Kurochko wrote:
> Because printk() relies on a serial driver (like the ns16550 driver)
> and drivers require working virtual memory (ioremap()) there is not
> print functionality early in Xen boot.
>
> The patch introduces the basic stuff of early_printk functionality
> which will be enough to print 'hello from C environment".
>
> Originally early_printk.{c,h} was introduced by Bobby Eshleman
> (https://github.com/glg-rv/xen/commit/a3c9916bbdff7ad6030055bbee7e53d1aab71384)
> but some functionality was changed:
> early_printk() function was changed in comparison with the original as
> common isn't being built now so there is no vscnprintf.
>
> This commit adds early printk implementation built on the putc SBI call.
>
> As sbi_console_putchar() is already being planned for deprecation
> it is used temporarily now and will be removed or reworked after
> real uart will be ready.
>
> Signed-off-by: Bobby Eshleman <bobby.eshleman@xxxxxxxxx>
> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
> Reviewed-by: Bobby Eshleman <bobby.eshleman@xxxxxxxxx>
> ---
> Changes in V6:
>      - Remove __riscv_cmodel_medany check from early_printk.c
Why? I know Andrew believed this is wrong, but I replied back with my 
understanding and saw no discussion afterwards explaining why I am 
incorrect.
I am not a maintainer of the code here, but I don't particularly 
appreciate comments to be ignored. If there was any discussion on IRC, 
then please summarize them here.
Cheers,

--
Julien Grall