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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, James Hogan <jhogan@kernel.org>,
        Paul Burton <paul.burton@mips.com>, linux-mips@linux-mips.org,
        Ralf Baechle <ralf@linux-mips.org>
Subject: [PATCH 4.14 78/89] MIPS: CM: Drop WARN_ON(vp != 0)
Date:   Mon, 22 Jan 2018 09:45:58 +0100
Message-Id: <20180122084002.242771771@linuxfoundation.org>
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4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: James Hogan <jhogan@kernel.org>

commit c04de7b1ad645b61c141df8ca903ba0cc03a57f7 upstream.

Since commit 68923cdc2eb3 ("MIPS: CM: Add cluster & block args to
mips_cm_lock_other()"), mips_smp_send_ipi_mask() has used
mips_cm_lock_other_cpu() with each CPU number, rather than
mips_cm_lock_other() with the first VPE in each core. Prior to r6,
multicore multithreaded systems such as dual-core dual-thread
interAptivs with CPU Idle enabled (e.g. MIPS Creator Ci40) results in
mips_cm_lock_other() repeatedly hitting WARN_ON(vp != 0).

There doesn't appear to be anything fundamentally wrong about passing a
non-zero VP/VPE number, even if it is a core's region that is locked
into the other region before r6, so remove that particular WARN_ON().

Fixes: 68923cdc2eb3 ("MIPS: CM: Add cluster & block args to mips_cm_lock_other()")
Signed-off-by: James Hogan <jhogan@kernel.org>
Reviewed-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17883/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/kernel/mips-cm.c |    1 -
 1 file changed, 1 deletion(-)

--- a/arch/mips/kernel/mips-cm.c
+++ b/arch/mips/kernel/mips-cm.c
@@ -292,7 +292,6 @@ void mips_cm_lock_other(unsigned int clu
 				  *this_cpu_ptr(&cm_core_lock_flags));
 	} else {
 		WARN_ON(cluster != 0);
-		WARN_ON(vp != 0);
 		WARN_ON(block != CM_GCR_Cx_OTHER_BLOCK_LOCAL);
 
 		/*