On 9/1/20 6:59 PM, Thomas Huth wrote:
> On 31/08/2020 17.09, 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 <fran...@linux.ibm.com>
>> ---
>> pc-bios/s390-ccw/bootmap.c | 3 ++-
>> pc-bios/s390-ccw/jump2ipl.c | 22 +++++++++++++++++-----
>> pc-bios/s390-ccw/s390-ccw.h | 1 +
>> 3 files changed, 20 insertions(+), 6 deletions(-)
>>
>> diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c
>> index 8747c4ea26..5a03b1eb8b 100644
>> --- a/pc-bios/s390-ccw/bootmap.c
>> +++ b/pc-bios/s390-ccw/bootmap.c
>> @@ -515,7 +515,8 @@ 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..5b8352d257 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 */
>> @@ -43,9 +49,10 @@ 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;
>> + if (address) {
>> + save_psw = *reset_psw;
>> + write_reset_psw(RESET_PSW);
>> + }
>> ipl_continue = address;
>> debug_print_int("set IPL addr to", ipl_continue);
>
> In case you respin this series, I think I'd move the "ipl_continue =
> address" into the if-statement, too, and change the debug_print_int line
> to use address instead of ipl_continue.
Hmm, my intention was to always have something printed.
But I guess it would make more sense to print the reset psw addr in the
~address case.
>
>> @@ -77,7 +84,12 @@ void jump_to_low_kernel(void)
>>
>> /* Trying to get PSW at zero address */
>> if (*((uint64_t *)0) & RESET_PSW_MASK) {
>> - jump_to_IPL_code((*((uint64_t *)0)) & PSW_MASK_SHORT_ADDR);
>> + /*
>> + * Surely nobody will try running directly from lowcore, so
>> + * let's use 0 as an indication that we want to load the reset
>> + * psw at 0x0 and not jump to the entry.
>> + */
>> + jump_to_IPL_code(0);
>> }
>>
>> /* No other option left, so use the Linux kernel start address */
>> diff --git a/pc-bios/s390-ccw/s390-ccw.h b/pc-bios/s390-ccw/s390-ccw.h
>> index 36b884cced..7090720422 100644
>> --- a/pc-bios/s390-ccw/s390-ccw.h
>> +++ b/pc-bios/s390-ccw/s390-ccw.h
>> @@ -78,6 +78,7 @@ int virtio_read(ulong sector, void *load_addr);
>> void zipl_load(void);
>>
>> /* jump2ipl.c */
>> +void write_reset_psw(uint64_t psw);
>> void jump_to_IPL_code(uint64_t address);
>> void jump_to_low_kernel(void);
>
> Looks sane to me:
>
> Reviewed-by: Thomas Huth <th...@redhat.com>
>
>
signature.asc
Description: OpenPGP digital signature
