[PATCH AUTOSEL 6.11 19/76] s390/traps: Handle early warnings gracefully

Sasha Levin
2024-10-04T18:19:02Z

From: Heiko Carstens <hca@linux.ibm.com>

[ Upstream commit 3c4d0ae0671827f4b536cc2d26f8b9c54584ccc5 ]

Add missing warning handling to the early program check handler. This
way a warning is printed to the console as soon as the early console
is setup, and the kernel continues to boot.

Before this change a disabled wait psw was loaded instead and the
machine was silently stopped without giving an idea about what
happened.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/s390/kernel/early.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 14d324865e33f..ecae246e8d5d4 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -177,8 +177,21 @@ static __init void setup_topology(void)

void __do_early_pgm_check(struct pt_regs *regs)
{
- if (!fixup_exception(regs))
- disabled_wait();
+ struct lowcore *lc = get_lowcore();
+ unsigned long ip;
+
+ regs->int_code = lc->pgm_int_code;
+ regs->int_parm_long = lc->trans_exc_code;
+ ip = __rewind_psw(regs->psw, regs->int_code >> 16);
+
+ /* Monitor Event? Might be a warning */
+ if ((regs->int_code & PGM_INT_CODE_MASK) == 0x40) {
+ if (report_bug(ip, regs) == BUG_TRAP_TYPE_WARN)
+ return;
+ }
+ if (fixup_exception(regs))
+ return;
+ disabled_wait();
}

static noinline __init void setup_lowcore_early(void)
--
2.43.0