Bug 1262471

Summary:	decode clflushopt instruction
Product:	Red Hat Enterprise Linux 7	Reporter:	Jeff Bastian <jbastian>
Component:	gdb	Assignee:	Jan Kratochvil <jan.kratochvil>
Status:	CLOSED ERRATA	QA Contact:	qe-baseos-tools-bugs
Severity:	low	Docs Contact:
Priority:	low
Version:	7.2	CC:	anderson, gdb-bugs, jan.kratochvil, mcermak, ohudlick, sergiodj
Target Milestone:	rc
Target Release:	7.3
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:	gdb-7.6.1-84.el7	Doc Type:	No Doc Update
Doc Text:	undefined	Story Points:	---
Clone Of:
Clones:	1262479 1357895 (view as bug list)		Environment:
Last Closed:	2016-11-04 03:49:47 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	1262479, 1297579, 1313485, 1357895

Description Jeff Bastian 2015-09-11 20:08:35 UTC

Description of problem:
Please add support to gdb and crash to decode the new CLFLUSHOPT instruction (in Intel Skylake and newer CPUs).  Currently gdb shows the 0x66 prefix as a separate instruction, but objdump decodes it correctly:

$ echo 'int main(void) { asm volatile("clflushopt (%rdi)"); }' > clflushopt.c
$ gcc -g clflushopt.c
$ objdump -d a.out | grep clflush
  4004f4:       66 0f ae 3f             clflushopt (%rdi)
$ gdb -q ./a.out
Reading symbols from /tmp/clflushopt/a.out...done.
(gdb) disas /r main
Dump of assembler code for function main:
...
   0x00000000004004f4 <+4>:     66      data16
   0x00000000004004f5 <+5>:     0f ae 3f        clflush (%rdi)


Version-Release number of selected component (if applicable):
gdb-7.6.1-78.el7
crash-7.1.2-2.el7

How reproducible:
always

Steps to Reproduce:
1. see above

Actual results:
   0x00000000004004f4 <+4>:     66      data16
   0x00000000004004f5 <+5>:     0f ae 3f        clflush (%rdi)

Expected results:
   0x00000000004004f4 <+4>:     66 0f ae 3f     clflushopt (%rdi)

Additional info:
See bug 1170846 comment 19 for where the issue was seen with crash

Comment 5 errata-xmlrpc 2016-11-04 03:49:47 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2016-2328.html