MIPS: CPC: Avoid lock when MIPS CM >= 3 is present (d6219420) · Commits · 戴 / test

MIPS CM version 3 removed the CPC_CL_OTHER register and instead the CM_CL_OTHER register is used to redirect the CPC_OTHER region. As such, we should not write the unimplmented register and can avoid the spinlock as well. These lock functions should aleady be called within the context of a mips_cm_{lock,unlock}_other pair ensuring the correct CPC_OTHER region will be accessed. Signed-off-by:

Matt Redfearn <matt.redfearn@imgtec.com> Reviewed-by:

Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14219/ Signed-off-by:

Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/mips-cpc.c

+12 −1

Original line number	Diff line number	Diff line
		@@ -71,6 +71,11 @@ int mips_cpc_probe(void)
		void mips_cpc_lock_other(unsigned int core)
		{
		unsigned int curr_core;

		if (mips_cm_revision() >= CM_REV_CM3)
		/* Systems with CM >= 3 lock the CPC via mips_cm_lock_other */
		return;

		preempt_disable();
		curr_core = current_cpu_data.core;
		spin_lock_irqsave(&per_cpu(cpc_core_lock, curr_core),
		@@ -86,7 +91,13 @@ void mips_cpc_lock_other(unsigned int core)

		void mips_cpc_unlock_other(void)
		{
		unsigned int curr_core = current_cpu_data.core;
		unsigned int curr_core;

		if (mips_cm_revision() >= CM_REV_CM3)
		/* Systems with CM >= 3 lock the CPC via mips_cm_lock_other */
		return;

		curr_core = current_cpu_data.core;
		spin_unlock_irqrestore(&per_cpu(cpc_core_lock, curr_core),
		per_cpu(cpc_core_lock_flags, curr_core));
		preempt_enable();

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