[3.8.y.z extended stable] Patch "turbostat: Use GCC's CPUID functions to support PIC" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    turbostat: Use GCC's CPUID functions to support PIC

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.18.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 47f613c50c7f92288d8443941a151c56a87ed967 Mon Sep 17 00:00:00 2001
From: Josh Triplett <josh at joshtriplett.org>
Date: Tue, 20 Aug 2013 17:20:14 -0700
Subject: turbostat: Use GCC's CPUID functions to support PIC
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit 2b92865e648ce04a39fda4f903784a5d01ecb0dc upstream.

turbostat uses inline assembly to call cpuid.  On 32-bit x86, on systems
that have certain security features enabled by default that make -fPIC
the default, this causes a build error:

turbostat.c: In function ‘check_cpuid’:
turbostat.c:1906:2: error: PIC register clobbered by ‘ebx’ in ‘asm’
  asm("cpuid" : "=a" (fms), "=c" (ecx), "=d" (edx) : "a" (1) : "ebx");
  ^

GCC provides a header cpuid.h, containing a __get_cpuid function that
works with both PIC and non-PIC.  (On PIC, it saves and restores ebx
around the cpuid instruction.)  Use that instead.

Signed-off-by: Josh Triplett <josh at joshtriplett.org>
Signed-off-by: Len Brown <len.brown at intel.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 tools/power/x86/turbostat/turbostat.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 10f4d14..1f4d8df 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -35,6 +35,7 @@
 #include <string.h>
 #include <ctype.h>
 #include <sched.h>
+#include <cpuid.h>

 char *proc_stat = "/proc/stat";
 unsigned int interval_sec = 5;	/* set with -i interval_sec */
@@ -1810,7 +1811,7 @@ void check_cpuid()

 	eax = ebx = ecx = edx = 0;

-	asm("cpuid" : "=a" (max_level), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (0));
+	__get_cpuid(0, &max_level, &ebx, &ecx, &edx);

 	if (ebx == 0x756e6547 && edx == 0x49656e69 && ecx == 0x6c65746e)
 		genuine_intel = 1;
@@ -1819,7 +1820,7 @@ void check_cpuid()
 		fprintf(stderr, "CPUID(0): %.4s%.4s%.4s ",
 			(char *)&ebx, (char *)&edx, (char *)&ecx);

-	asm("cpuid" : "=a" (fms), "=c" (ecx), "=d" (edx) : "a" (1) : "ebx");
+	__get_cpuid(1, &fms, &ebx, &ecx, &edx);
 	family = (fms >> 8) & 0xf;
 	model = (fms >> 4) & 0xf;
 	stepping = fms & 0xf;
@@ -1841,7 +1842,7 @@ void check_cpuid()
 	 * This check is valid for both Intel and AMD.
 	 */
 	ebx = ecx = edx = 0;
-	asm("cpuid" : "=a" (max_level), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (0x80000000));
+	__get_cpuid(0x80000000, &max_level, &ebx, &ecx, &edx);

 	if (max_level < 0x80000007) {
 		fprintf(stderr, "CPUID: no invariant TSC (max_level 0x%x)\n", max_level);
@@ -1852,7 +1853,7 @@ void check_cpuid()
 	 * Non-Stop TSC is advertised by CPUID.EAX=0x80000007: EDX.bit8
 	 * this check is valid for both Intel and AMD
 	 */
-	asm("cpuid" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (0x80000007));
+	__get_cpuid(0x80000007, &eax, &ebx, &ecx, &edx);
 	has_invariant_tsc = edx & (1 << 8);

 	if (!has_invariant_tsc) {
@@ -1865,7 +1866,7 @@ void check_cpuid()
 	 * this check is valid for both Intel and AMD
 	 */

-	asm("cpuid" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (0x6));
+	__get_cpuid(0x6, &eax, &ebx, &ecx, &edx);
 	has_aperf = ecx & (1 << 0);
 	do_dts = eax & (1 << 0);
 	do_ptm = eax & (1 << 6);
--
1.8.3.2