svn commit: r355060 - head/sys/amd64/include

[Konstantin Belousov]

Author: kib
Date: Sun Nov 24 19:02:13 2019
New Revision: 355060
URL: https://svnweb.freebsd.org/changeset/base/355060

Log:
  amd64: assert that EARLY_COUNTER does not corrupt memory.
  
  Reviewed by:	imp
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week
  Differential revision:	https://reviews.freebsd.org/D22514

Modified:
  head/sys/amd64/include/counter.h

Modified: head/sys/amd64/include/counter.h
==============================================================================
--- head/sys/amd64/include/counter.h	Sun Nov 24 16:40:54 2019	(r355059)
+++ head/sys/amd64/include/counter.h	Sun Nov 24 19:02:13 2019	(r355060)
@@ -82,6 +82,7 @@ static inline void
 counter_u64_add(counter_u64_t c, int64_t inc)
 {
 
+	KASSERT(IS_BSP() || c != EARLY_COUNTER, ("EARLY_COUNTER used on AP"));
 	__asm __volatile("addq\t%1,%%gs:(%0)"
 	    :
 	    : "r" ((char *)c - (char *)&__pcpu[0]), "ri" (inc)