[PATCH 03/32] s390: Clear pt_regs flags field

[Heiko Carstens <hca@linux.ibm.com>]

Clear the pt_regs flags field in the early program check handler as well
as in the stack_invalid handler. Without this the pt_regs flags field will
have random values, depending on previous stack contents.

This matters currently for bug reporting and disassembly, where flags like
PIF_PSW_ADDR_ADJUSTED may then be incorrectly set, which could lead to a
partially incorrect disassembly or wrong code markers.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
 arch/s390/kernel/early.c | 1 +
 arch/s390/kernel/entry.S | 1 +
 2 files changed, 2 insertions(+)

diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 1fc153d8385b..b8e3c065fbec 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -154,6 +154,7 @@ void __init __do_early_pgm_check(struct pt_regs *regs)
 {
 	struct lowcore *lc = get_lowcore();
 
+	regs->flags = 0;
 	regs->int_code = lc->pgm_int_code;
 	regs->int_parm_long = lc->trans_exc_code;
 	regs->last_break = lc->pgm_last_break;
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 10dd9bbdf985..f51ecd8e7d21 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -621,6 +621,7 @@ SYM_CODE_START(stack_invalid)
 	stmg	%r0,%r7,__PT_R0(%r11)
 	stmg	%r8,%r9,__PT_PSW(%r11)
 	mvc	__PT_R8(64,%r11),0(%r14)
+	xc	__PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
 	GET_LC	%r2
 	mvc	__PT_ORIG_GPR2(8,%r11),__LC_PGM_LAST_BREAK(%r2)
 	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
-- 
2.53.0