diff mbox series

[v4,1/2] powerpc/mce: remove nmi_enter/exit from real mode handler

Message ID 20201009064005.19777-2-ganeshgr@linux.ibm.com (mailing list archive)
State Accepted
Commit 8d0e2101274358d9b6b1f27232b40253ca48bab5
Headers show
Series powerpc/mce: Fix mce handler and add selftest | expand

Checks

Context Check Description
snowpatch_ozlabs/apply_patch success Successfully applied on branch powerpc/merge (118be7377c97e35c33819bcb3bbbae5a42a4ac43)
snowpatch_ozlabs/checkpatch success total: 0 errors, 0 warnings, 0 checks, 22 lines checked
snowpatch_ozlabs/needsstable warning Please consider tagging this patch for stable!

Commit Message

Ganesh Goudar Oct. 9, 2020, 6:40 a.m. UTC 
Use of nmi_enter/exit in real mode handler causes the kernel to panic
and reboot on injecting slb mutihit on pseries machine running in hash
mmu mode, As these calls try to accesses memory outside RMO region in
real mode handler where translation is disabled.

Add check to not to use these calls on pseries machine running in hash
mmu mode.

Fixes: 116ac378bb3f ("powerpc/64s: machine check interrupt update NMI accounting")
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
---
 arch/powerpc/kernel/mce.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
index ada59f6c4298..63702c0badb9 100644
--- a/arch/powerpc/kernel/mce.c
+++ b/arch/powerpc/kernel/mce.c
@@ -591,12 +591,11 @@  EXPORT_SYMBOL_GPL(machine_check_print_event_info);
 long notrace machine_check_early(struct pt_regs *regs)
 {
 	long handled = 0;
-	bool nested = in_nmi();
 	u8 ftrace_enabled = this_cpu_get_ftrace_enabled();
 
 	this_cpu_set_ftrace_enabled(0);
-
-	if (!nested)
+	/* Do not use nmi_enter/exit for pseries hpte guest */
+	if (radix_enabled() || !firmware_has_feature(FW_FEATURE_LPAR))
 		nmi_enter();
 
 	hv_nmi_check_nonrecoverable(regs);
@@ -607,7 +606,7 @@  long notrace machine_check_early(struct pt_regs *regs)
 	if (ppc_md.machine_check_early)
 		handled = ppc_md.machine_check_early(regs);
 
-	if (!nested)
+	if (radix_enabled() || !firmware_has_feature(FW_FEATURE_LPAR))
 		nmi_exit();
 
 	this_cpu_set_ftrace_enabled(ftrace_enabled);