Re: [PATCH v4 3/4] pc-bios: s390x: Use reset PSW if avaliable

[Thomas Huth <thuth@redhat.com>]

On 06/10/2020 11.42, Janosch Frank wrote:
> If a blob provides a reset PSW then we should use it instead of
> branching to the PSW address and using our own mask.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> ---
>   pc-bios/s390-ccw/bootmap.c  |  6 ++++--
>   pc-bios/s390-ccw/jump2ipl.c | 26 +++++++++++++++++++-------
>   pc-bios/s390-ccw/s390-ccw.h |  1 +
>   3 files changed, 24 insertions(+), 9 deletions(-)
> 
> diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c
> index 8747c4ea26..88bd12d5d7 100644
> --- a/pc-bios/s390-ccw/bootmap.c
> +++ b/pc-bios/s390-ccw/bootmap.c
> @@ -273,7 +273,8 @@ static void run_eckd_boot_script(block_number_t bmt_block_nr,
>   
>       IPL_assert(bms->entry[i].type == BOOT_SCRIPT_EXEC,
>                  "Unknown script entry type");
> -    jump_to_IPL_code(bms->entry[i].address.load_address); /* no return */
> +    write_reset_psw(bms->entry[i].address.load_address); /* no return */
> +    jump_to_IPL_code(0); /* no return */
>   }
>   
>   static void ipl_eckd_cdl(void)
> @@ -515,7 +516,8 @@ static void zipl_run(ScsiBlockPtr *pte)
>       IPL_assert(entry->component_type == ZIPL_COMP_ENTRY_EXEC, "No EXEC entry");
>   
>       /* should not return */
> -    jump_to_IPL_code(entry->compdat.load_psw & PSW_MASK_SHORT_ADDR);
> +    write_reset_psw(entry->compdat.load_psw);
> +    jump_to_IPL_code(0);
>   }
>   
>   static void ipl_scsi(void)
> diff --git a/pc-bios/s390-ccw/jump2ipl.c b/pc-bios/s390-ccw/jump2ipl.c
> index b6aad32def..63afa4a349 100644
> --- a/pc-bios/s390-ccw/jump2ipl.c
> +++ b/pc-bios/s390-ccw/jump2ipl.c
> @@ -12,15 +12,21 @@
>   
>   #define KERN_IMAGE_START 0x010000UL
>   #define RESET_PSW_MASK (PSW_MASK_SHORTPSW | PSW_MASK_64)
> +#define RESET_PSW ((uint64_t)&jump_to_IPL_addr | RESET_PSW_MASK)
>   
>   static uint64_t *reset_psw = 0, save_psw, ipl_continue;
>   
> +void write_reset_psw(uint64_t psw)
> +{
> +    *reset_psw = psw;
> +}
> +
>   static void jump_to_IPL_addr(void)
>   {
>       __attribute__((noreturn)) void (*ipl)(void) = (void *)ipl_continue;
>   
>       /* Restore reset PSW */
> -    *reset_psw = save_psw;
> +    write_reset_psw(save_psw);
>   
>       ipl();
>       /* should not return */
> @@ -43,11 +49,12 @@ void jump_to_IPL_code(uint64_t address)
>        * content of non-BIOS memory after we loaded the guest, so we
>        * save the original content and restore it in jump_to_IPL_2.
>        */
> -    save_psw = *reset_psw;
> -    *reset_psw = (uint64_t) &jump_to_IPL_addr;
> -    *reset_psw |= RESET_PSW_MASK;
> -    ipl_continue = address;
> -    debug_print_int("set IPL addr to", ipl_continue);
> +    if (address) {
> +        save_psw = *reset_psw;
> +        write_reset_psw(RESET_PSW);
> +        ipl_continue = address;
> +    }
> +    debug_print_int("set IPL addr to", address ? address : *reset_psw & PSW_MASK_SHORT_ADDR);

checkpatch.pl complains about a very long line here...
I'll change this line to use the Elvis operator, so that is a little bit 
short, ok?

  Thomas