linux-kernel - [patch 84/83] powerpc: Use cpu_thread_in_core in smp_init for of_spin

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20081212052123.GB9024@kroah.com>
Date:	Thu, 11 Dec 2008 21:21:23 -0800
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org,
	Theodore Ts'o <tytso@....edu>,
	Zwane Mwaikambo <zwane@....linux.org.uk>,
	Eugene Teo <eteo@...hat.com>,
	Justin Forbes <jmforbes@...uxtx.org>,
	Domenico Andreoli <cavokz@...il.com>,
	Chris Wedgwood <reviews@...cw.f00f.org>,
	Jake Edge <jake@....net>, Randy Dunlap <rdunlap@...otime.net>,
	Michael Krufky <mkrufky@...uxtv.org>, alan@...rguk.ukuu.org.uk,
	Chuck Ebbert <cebbert@...hat.com>,
	Dave Jones <davej@...hat.com>,
	Chuck Wolber <chuckw@...ntumlinux.com>,
	akpm@...ux-foundation.org, torvalds@...ux-foundation.org,
	Willy Tarreau <w@....eu>,
	Rodrigo Rubira Branco <rbranco@...checkpoint.com>,
	Milton Miller <miltonm@....com>
Subject: [patch 84/83] powerpc: Use cpu_thread_in_core in smp_init for
	of_spin_map

From: Milton Miller <miltonm@....com>

commit 6a75a6b8e85e92cc774d42a4e113c76c30b5a539 upstream.

We used to assume that even numbered threads were the primary
threads, ie those that would be listed and started as a cpu from
open firmware.  Replace a left over is even (% 2) check with a check
for it being a primary thread and update the comments.

Tested with a debug print on pseries, identical code found for cell.

Signed-off-by: Milton Miller <miltonm@....com>
Signed-off-by: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 arch/powerpc/platforms/cell/smp.c    |   10 +++-------
 arch/powerpc/platforms/pseries/smp.c |   13 ++++---------
 2 files changed, 7 insertions(+), 16 deletions(-)

--- a/arch/powerpc/platforms/cell/smp.c
+++ b/arch/powerpc/platforms/cell/smp.c
@@ -54,8 +54,8 @@
 #endif
 
 /*
- * The primary thread of each non-boot processor is recorded here before
- * smp init.
+ * The Primary thread of each non-boot processor was started from the OF client
+ * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop.
  */
 static cpumask_t of_spin_map;
 
@@ -208,11 +208,7 @@ void __init smp_init_cell(void)
 	/* Mark threads which are still spinning in hold loops. */
 	if (cpu_has_feature(CPU_FTR_SMT)) {
 		for_each_present_cpu(i) {
-			if (i % 2 == 0)
-				/*
-				 * Even-numbered logical cpus correspond to
-				 * primary threads.
-				 */
+			if (cpu_thread_in_core(i) == 0)
 				cpu_set(i, of_spin_map);
 		}
 	} else {
--- a/arch/powerpc/platforms/pseries/smp.c
+++ b/arch/powerpc/platforms/pseries/smp.c
@@ -52,8 +52,8 @@
 
 
 /*
- * The primary thread of each non-boot processor is recorded here before
- * smp init.
+ * The Primary thread of each non-boot processor was started from the OF client
+ * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop.
  */
 static cpumask_t of_spin_map;
 
@@ -191,8 +191,7 @@ static void __devinit smp_pSeries_kick_c
 static int smp_pSeries_cpu_bootable(unsigned int nr)
 {
 	/* Special case - we inhibit secondary thread startup
-	 * during boot if the user requests it.  Odd-numbered
-	 * cpus are assumed to be secondary threads.
+	 * during boot if the user requests it.
 	 */
 	if (system_state < SYSTEM_RUNNING &&
 	    cpu_has_feature(CPU_FTR_SMT) &&
@@ -229,11 +228,7 @@ static void __init smp_init_pseries(void
 	/* Mark threads which are still spinning in hold loops. */
 	if (cpu_has_feature(CPU_FTR_SMT)) {
 		for_each_present_cpu(i) { 
-			if (i % 2 == 0)
-				/*
-				 * Even-numbered logical cpus correspond to
-				 * primary threads.
-				 */
+			if (cpu_thread_in_core(i) == 0)
 				cpu_set(i, of_spin_map);
 		}
 	} else {
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/