Re: [PATCH v3 3/3] xen/riscv: initialize .bss section

[Bobby Eshleman <bobbyeshleman@xxxxxxxxx>]

On Fri, Mar 03, 2023 at 12:24:24PM +0200, Oleksii Kurochko wrote:
> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
> ---
>  xen/arch/riscv/riscv64/head.S | 9 +++++++++
>  xen/arch/riscv/setup.c        | 8 ++++++++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/xen/arch/riscv/riscv64/head.S b/xen/arch/riscv/riscv64/head.S
> index adf5d6c74a..8887f0cbd4 100644
> --- a/xen/arch/riscv/riscv64/head.S
> +++ b/xen/arch/riscv/riscv64/head.S
> @@ -1,3 +1,4 @@
> +#include <asm/asm.h>
>  #include <asm/riscv_encoding.h>
>  
>          .section .text.header, "ax", %progbits
> @@ -18,6 +19,14 @@ ENTRY(start)
>          li      t0, SSTATUS_FS
>          csrc    CSR_SSTATUS, t0
>  
> +        /* Clear the BSS */
> +        la      t3, __bss_start
> +        la      t4, __bss_end
> +.L_clear_bss:
> +        REG_S   zero, (t3)
> +        add     t3, t3, __SIZEOF_POINTER__
> +        bltu    t3, t4, .L_clear_bss
> +
>          la      sp, cpu0_boot_stack
>          li      t0, STACK_SIZE
>          add     sp, sp, t0
> diff --git a/xen/arch/riscv/setup.c b/xen/arch/riscv/setup.c
> index d9723fe1c0..929565720b 100644
> --- a/xen/arch/riscv/setup.c
> +++ b/xen/arch/riscv/setup.c
> @@ -7,6 +7,14 @@
>  unsigned char __initdata cpu0_boot_stack[STACK_SIZE]
>      __aligned(STACK_SIZE);
>  
> +/*  
> + * To be sure that .bss isn't zero. It will simplify code of
> + * .bss initialization.
> + * TODO:
> + *   To be deleted when the first real .bss user appears
> + */
> +int dummy_bss __attribute__((unused));
> +
>  void __init noreturn start_xen(unsigned long bootcpu_id,
>                                 unsigned long dtb_base)
>  {
> -- 
> 2.39.0
> 
> 

Reviewed-by: Bobby Eshleman <bobbyeshleman@xxxxxxxxx>