Re: [PATCH v3 5/6] xen/riscv: introduce early_printk basic stuff

[Jan Beulich <jbeulich@xxxxxxxx>]

On 10.01.2023 16:17, Oleksii Kurochko wrote:
> --- a/xen/arch/riscv/Kconfig.debug
> +++ b/xen/arch/riscv/Kconfig.debug
> @@ -0,0 +1,7 @@
> +config EARLY_PRINTK
> +    bool "Enable early printk"
> +    default DEBUG
> +    depends on RISCV_64 || RISCV_32

You're in a RISC-V-specific Kconfig - do you really need this line?

> --- /dev/null
> +++ b/xen/arch/riscv/early_printk.c
> @@ -0,0 +1,33 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * RISC-V early printk using SBI
> + *
> + * Copyright (C) 2021 Bobby Eshleman <bobbyeshleman@xxxxxxxxx>
> + */
> +#include <asm/early_printk.h>
> +#include <asm/sbi.h>
> +
> +/*
> + * TODO:
> + *   sbi_console_putchar is already planned for deprecation
> + *   so it should be reworked to use UART directly.
> +*/
> +void early_puts(const char *s, size_t nr)
> +{
> +    while ( nr-- > 0 )
> +    {
> +        if (*s == '\n')

Nit (style): Missing blanks.

> +            sbi_console_putchar('\r');
> +        sbi_console_putchar(*s);
> +        s++;
> +    }
> +}
> +
> +void early_printk(const char *str)
> +{
> +    while (*str)

Again.

> --- a/xen/arch/riscv/setup.c
> +++ b/xen/arch/riscv/setup.c
> @@ -1,12 +1,16 @@
>  #include <xen/compile.h>
>  #include <xen/init.h>
>  
> +#include <asm/early_printk.h>
> +
>  /* Xen stack for bringing up the first CPU. */
>  unsigned char __initdata cpu0_boot_stack[STACK_SIZE]
>      __aligned(STACK_SIZE);
>  
>  void __init noreturn start_xen(void)
>  {
> +    early_printk("Hello from C env\n");
> +
>      for ( ;; )
>          asm volatile ("wfi");

While this is only context here, it affects an earlier patch in the
series; this wants to be

    for ( ; ; )
        asm volatile ( "wfi" );

Jan