svn commit: r311483 - stable/11/sys/dev/sfxge/common

[Andrew Rybchenko]

Author: arybchik
Date: Fri Jan  6 07:09:11 2017
New Revision: 311483
URL: https://svnweb.freebsd.org/changeset/base/311483

Log:
  MFC r310750
  
  sfxge(4): add missing barrier in common code MCDI response handling
  
  The semantics of the MCDI interfacve require reading the first
  dword of the header before any other data in the buffer. Add
  a barrier to the common code MCDI handler to enforce this.
  
  Submitted by:   Andy Moreton <amoreton at solarflare.com>
  Sponsored by:   Solarflare Communications, Inc.

Modified:
  stable/11/sys/dev/sfxge/common/ef10_mcdi.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/dev/sfxge/common/ef10_mcdi.c
==============================================================================
--- stable/11/sys/dev/sfxge/common/ef10_mcdi.c	Fri Jan  6 07:08:09 2017	(r311482)
+++ stable/11/sys/dev/sfxge/common/ef10_mcdi.c	Fri Jan  6 07:09:11 2017	(r311483)
@@ -159,6 +159,8 @@ ef10_mcdi_poll_response(
 	efx_dword_t hdr;
 
 	EFSYS_MEM_READD(esmp, 0, &hdr);
+	EFSYS_MEM_READ_BARRIER();
+
 	return (EFX_DWORD_FIELD(hdr, MCDI_HEADER_RESPONSE) ? B_TRUE : B_FALSE);
 }