linux-kernel - [PATCH 14/15] MIPS: smp-cps: Add nothreads kernel parameter

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Message-ID: <1454469335-14778-15-git-send-email-paul.burton@imgtec.com>
Date:	Wed, 3 Feb 2016 03:15:34 +0000
From:	Paul Burton <paul.burton@...tec.com>
To:	<linux-mips@...ux-mips.org>, Ralf Baechle <ralf@...ux-mips.org>
CC:	Paul Burton <paul.burton@...tec.com>,
	Matt Redfearn <matt.redfearn@...tec.com>,
	Rusty Russell <rusty@...tcorp.com.au>,
	<linux-kernel@...r.kernel.org>,
	Niklas Cassel <niklas.cassel@...s.com>,
	Ezequiel Garcia <ezequiel.garcia@...tec.com>,
	Markos Chandras <markos.chandras@...tec.com>
Subject: [PATCH 14/15] MIPS: smp-cps: Add nothreads kernel parameter

When debugging a new system or core it can be useful to disable the use
of multithreading. Introduce a "nothreads" kernel command line parameter
that can be set in order to do so.

Signed-off-by: Paul Burton <paul.burton@...tec.com>
---

 arch/mips/kernel/smp-cps.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/mips/kernel/smp-cps.c b/arch/mips/kernel/smp-cps.c
index 27f1c04..23c29fc 100644
--- a/arch/mips/kernel/smp-cps.c
+++ b/arch/mips/kernel/smp-cps.c
@@ -27,14 +27,25 @@
 #include <asm/time.h>
 #include <asm/uasm.h>
 
+static bool threads_disabled;
 static DECLARE_BITMAP(core_power, NR_CPUS);
 
 struct core_boot_config *mips_cps_core_bootcfg;
 
+static int __init setup_nothreads(char *s)
+{
+	threads_disabled = true;
+	return 0;
+}
+early_param("nothreads", setup_nothreads);
+
 static unsigned core_vpe_count(unsigned core)
 {
 	unsigned cfg;
 
+	if (threads_disabled)
+		return 1;
+
 	if ((!config_enabled(CONFIG_MIPS_MT_SMP) || !cpu_has_mipsmt)
 		&& (!config_enabled(CONFIG_CPU_MIPSR6) || !cpu_has_vp))
 		return 1;
-- 
2.7.0