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 <[email protected]> --- pc-bios/s390-ccw/bootmap.c | 1 + pc-bios/s390-ccw/jump2ipl.c | 48 ++++++++++++++++++++++--------------- pc-bios/s390-ccw/s390-ccw.h | 1 + 3 files changed, 31 insertions(+), 19 deletions(-) diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c index 8747c4ea26..0df9b3781d 100644 --- a/pc-bios/s390-ccw/bootmap.c +++ b/pc-bios/s390-ccw/bootmap.c @@ -515,6 +515,7 @@ static void zipl_run(ScsiBlockPtr *pte) IPL_assert(entry->component_type == ZIPL_COMP_ENTRY_EXEC, "No EXEC entry"); /* should not return */ + write_reset_psw(entry->compdat.load_psw); jump_to_IPL_code(entry->compdat.load_psw & PSW_MASK_SHORT_ADDR); } diff --git a/pc-bios/s390-ccw/jump2ipl.c b/pc-bios/s390-ccw/jump2ipl.c index 767012bf0c..143d027bf7 100644 --- a/pc-bios/s390-ccw/jump2ipl.c +++ b/pc-bios/s390-ccw/jump2ipl.c @@ -13,20 +13,28 @@ #define KERN_IMAGE_START 0x010000UL #define RESET_PSW_MASK (PSW_MASK_SHORTPSW | PSW_MASK_64) -typedef struct ResetInfo { - uint64_t ipl_psw; - uint32_t ipl_continue; -} ResetInfo; - -static ResetInfo save; +uint64_t *reset_psw = 0, save_psw, ipl_continue; static void jump_to_IPL_2(void) { - ResetInfo *current = 0; + /* Restore reset PSW and io and external new PSWs */ + *reset_psw = save_psw; - void (*ipl)(void) = (void *) (uint64_t) current->ipl_continue; - *current = save; - ipl(); /* should not return */ + /* No reset PSW, let's jump instead. */ + if (ipl_continue) { + void (*ipl)(void) = (void *) (uint64_t) ipl_continue; + ipl(); + } + + /* Reset PSW available, let's load it */ + asm volatile ("lpsw 0(%0)\n" + : : "a" (0):); + /* should not return */ +} + +void write_reset_psw(uint64_t psw) +{ + *reset_psw = psw; } void jump_to_IPL_code(uint64_t address) @@ -46,15 +54,12 @@ 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. */ - ResetInfo *current = 0; + save_psw = *reset_psw; + *reset_psw = (uint64_t) &jump_to_IPL_2; + *reset_psw |= RESET_PSW_MASK; + ipl_continue = address; - save = *current; - - current->ipl_psw = (uint64_t) &jump_to_IPL_2; - current->ipl_psw |= RESET_PSW_MASK; - current->ipl_continue = address & PSW_MASK_SHORT_ADDR; - - debug_print_int("set IPL addr to", current->ipl_continue); + debug_print_int("set IPL addr to", ipl_continue); /* Ensure the guest output starts fresh */ sclp_print("\n"); @@ -84,7 +89,12 @@ 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); -- 2.25.1
