linux-kernel - [PATCH 10/10] MIPS: CM,CPC: ensure core-other GCRs reflect the correct core

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Date:	Tue, 22 Sep 2015 11:12:18 -0700
From:	Paul Burton <paul.burton@...tec.com>
To:	<linux-mips@...ux-mips.org>
CC:	Paul Burton <paul.burton@...tec.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	<linux-kernel@...r.kernel.org>,
	Markos Chandras <markos.chandras@...tec.com>,
	Ralf Baechle <ralf@...ux-mips.org>
Subject: [PATCH 10/10] MIPS: CM,CPC: ensure core-other GCRs reflect the correct core

Ensure the update to which core the core-other GCR regions reflect has
taken place before any core-other GCRs are accessed by placing a memory
barrier (sync instruction) between the write to the core-other registers
and any such GCR accesses.

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

 arch/mips/kernel/mips-cm.c  | 6 ++++++
 arch/mips/kernel/mips-cpc.c | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/arch/mips/kernel/mips-cm.c b/arch/mips/kernel/mips-cm.c
index fef2647..485e441 100644
--- a/arch/mips/kernel/mips-cm.c
+++ b/arch/mips/kernel/mips-cm.c
@@ -278,6 +278,12 @@ void mips_cm_lock_other(unsigned int core, unsigned int vp)
 	}
 
 	write_gcr_cl_other(val);
+
+	/*
+	 * Ensure the core-other region reflects the appropriate core &
+	 * VP before any accesses to it occur.
+	 */
+	mb();
 }
 
 void mips_cm_unlock_other(void)
diff --git a/arch/mips/kernel/mips-cpc.c b/arch/mips/kernel/mips-cpc.c
index 8af4d62..566b8d2 100644
--- a/arch/mips/kernel/mips-cpc.c
+++ b/arch/mips/kernel/mips-cpc.c
@@ -76,6 +76,12 @@ void mips_cpc_lock_other(unsigned int core)
 	spin_lock_irqsave(&per_cpu(cpc_core_lock, curr_core),
 			  per_cpu(cpc_core_lock_flags, curr_core));
 	write_cpc_cl_other(core << CPC_Cx_OTHER_CORENUM_SHF);
+
+	/*
+	 * Ensure the core-other region reflects the appropriate core &
+	 * VP before any accesses to it occur.
+	 */
+	mb();
 }
 
 void mips_cpc_unlock_other(void)
-- 
2.5.3

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