Re: [PATCH] xen/arm: Fix compilation error when early printk is enabled

[Julien Grall <julien@xxxxxxx>]

Hi Jan,

On 21/01/2021 09:43, Jan Beulich wrote:
> On 21.01.2021 10:30, Michal Orzel wrote:
> > Fix compilation error when enabling early printk, introduced
> > by commit aa4b9d1ee6538b5cbe218d4d3fcdf9548130a063:
> > ```
> > debug.S: Assembler messages:
> > debug.S:31: Error: constant expression expected at operand 2 -- `ldr 
> > x15,=((0x00400000+(0)*PAGE_SIZE)+(0x1c090000&~PAGE_MASK))`
> > debug.S:38: Error: constant expression expected at operand 2 -- `ldr 
> > x15,=((0x00400000+(0)*PAGE_SIZE)+(0x1c090000&~PAGE_MASK))`
> > ```
> >
> > The fix is to include header <xen/page-size.h> which now contains
> > definitions for page/size/mask etc.
> >
> > Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx>
> I'm sorry for the breakage, but I wonder how I should have noticed
> the issue. In all the Arm .config-s I'm routinely building I can't
> even see ...
>
> > --- a/xen/include/asm-arm/early_printk.h
> > +++ b/xen/include/asm-arm/early_printk.h
> > @@ -10,6 +10,7 @@
> >   #ifndef __ARM_EARLY_PRINTK_H__
> >   #define __ARM_EARLY_PRINTK_H__
> >   
> > +#include <xen/page-size.h>
> >   
> >   #ifdef CONFIG_EARLY_PRINTK
> ... a respective Kconfig setting, i.e. it's not like I simply
> failed to enable it.
EARLY_PRINTK is defined in arch/arm/Kconfig.debug and is selected when 
you specify the UART to use.
Assuming you are only build testing, you could add the following for 
testing EARLY_PRINTK:
CONFIG_DEBUG=y
CONFIG_EARLY_UART_CHOICE_8250=y
CONFIG_EARLY_UART_8250=y
CONFIG_EARLY_PRINTK=y
CONFIG_EARLY_UART_BASE_ADDRESS=
CONFIG_EARLY_UART_8250_REG_SHIFT=0
CONFIG_EARLY_PRINTK_INC="debug-8250.inc"

Cheers,

--
Julien Grall