From 0861c7d3e048556841fa5085173660dceadc5646 Mon Sep 17 00:00:00 2001
From: Kyle Evans <kevans@FreeBSD.org>
Date: Sun, 27 Dec 2020 11:28:32 -0600
Subject: [PATCH] kern: efirt: enter runtime environment to deref efi_cfgtbl

This fixes an insta-panic when EFIIOC_GET_TABLE is used.

Reviewed by:	imp (earlier version), kib
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D27669
---
 sys/dev/efidev/efirt.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/sys/dev/efidev/efirt.c b/sys/dev/efidev/efirt.c
index df1f62f3912..269eb67cf01 100644
--- a/sys/dev/efidev/efirt.c
+++ b/sys/dev/efidev/efirt.c
@@ -314,18 +314,25 @@ efi_get_table(struct uuid *uuid, void **ptr)
 {
 	struct efi_cfgtbl *ct;
 	u_long count;
+	int error;
 
 	if (efi_cfgtbl == NULL || efi_systbl == NULL)
 		return (ENXIO);
+	error = efi_enter();
+	if (error != 0)
+		return (error);
 	count = efi_systbl->st_entries;
 	ct = efi_cfgtbl;
 	while (count--) {
 		if (!bcmp(&ct->ct_uuid, uuid, sizeof(*uuid))) {
 			*ptr = (void *)efi_phys_to_kva(ct->ct_data);
+			efi_leave();
 			return (0);
 		}
 		ct++;
 	}
+
+	efi_leave();
 	return (ENOENT);
 }
 
-- 
2.45.0