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

[Oleksii <oleksii.kurochko@xxxxxxxxx>]

On Fri, 2023-01-27 at 11:26 +0000, Julien Grall wrote:
> 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/a3c9916bbdff7ad6030055bbee7e53d
> > 1aab71384)
> > 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.
Sorry, I have to mentioned that in the description of patch series.

There is no any specific reason to remove and only one reason I decided
to remove the check was that the check wasn't present in original
Alistair/Bobby patches and based on my experiments with that patches 
all worked fine. ( at least with some additional patches from my side I
was able to run Dom0 with console )

I pushed a new version (v7) of the patch series ( as I missed to change
dependency for CI job ) so probably we have to open a discussion again
as Andrew don't answer for a long time.
> 
> Cheers,
> 
~ Oleksii