svn commit: r327801 - in head/sys: amd64/amd64 i386/i386

[Conrad Meyer]

Author: cem
Date: Wed Jan 10 22:41:00 2018
New Revision: 327801
URL: https://svnweb.freebsd.org/changeset/base/327801

Log:
  x86: Document purpose of _safe variants of {rd,wr}msr()
  
  Sponsored by:	Dell EMC Isilon

Modified:
  head/sys/amd64/amd64/support.S
  head/sys/i386/i386/support.s

Modified: head/sys/amd64/amd64/support.S
==============================================================================
--- head/sys/amd64/amd64/support.S	Wed Jan 10 22:20:49 2018	(r327800)
+++ head/sys/amd64/amd64/support.S	Wed Jan 10 22:41:00 2018	(r327801)
@@ -763,7 +763,8 @@ ENTRY(longjmp)
 END(longjmp)
 
 /*
- * Support for reading MSRs in the safe manner.
+ * Support for reading MSRs in the safe manner.  (Instead of panic on #gp,
+ * return an error.)
  */
 ENTRY(rdmsr_safe)
 /* int rdmsr_safe(u_int msr, uint64_t *data) */
@@ -783,7 +784,8 @@ ENTRY(rdmsr_safe)
 	ret
 
 /*
- * Support for writing MSRs in the safe manner.
+ * Support for writing MSRs in the safe manner.  (Instead of panic on #gp,
+ * return an error.)
  */
 ENTRY(wrmsr_safe)
 /* int wrmsr_safe(u_int msr, uint64_t data) */

Modified: head/sys/i386/i386/support.s
==============================================================================
--- head/sys/i386/i386/support.s	Wed Jan 10 22:20:49 2018	(r327800)
+++ head/sys/i386/i386/support.s	Wed Jan 10 22:41:00 2018	(r327801)
@@ -790,7 +790,8 @@ ENTRY(longjmp)
 END(longjmp)
 
 /*
- * Support for reading MSRs in the safe manner.
+ * Support for reading MSRs in the safe manner.  (Instead of panic on #gp,
+ * return an error.)
  */
 ENTRY(rdmsr_safe)
 /* int rdmsr_safe(u_int msr, uint64_t *data) */
@@ -810,7 +811,8 @@ ENTRY(rdmsr_safe)
 	ret
 
 /*
- * Support for writing MSRs in the safe manner.
+ * Support for writing MSRs in the safe manner.  (Instead of panic on #gp,
+ * return an error.)
  */
 ENTRY(wrmsr_safe)
 /* int wrmsr_safe(u_int msr, uint64_t data) */