ARM: 6987/1: l2x0: fix disabling function to avoid deadlock (38a8914f) · Commits · 戴 / test

The l2x0_disable function attempts to writel with the l2x0_lock held. This results in deadlock when the writel contains an outer_sync call for the platform since the l2x0_lock is already held by the disable function. A further problem is that disabling the L2 without flushing it first can lead to the spin_lock operation becoming visible after the spin_unlock, causing any subsequent L2 maintenance to deadlock. This patch replaces the writel with a call to writel_relaxed in the disabling code and adds a flush before disabling in the control register, preventing livelock from occurring. Acked-by:

Catalin Marinas <catalin.marinas@arm.com> Signed-off-by:

Will Deacon <will.deacon@arm.com> Signed-off-by:

Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/cache-l2x0.c

+13 −6

Original line number	Diff line number	Diff line
		@@ -120,17 +120,22 @@ static void l2x0_cache_sync(void)
		spin_unlock_irqrestore(&l2x0_lock, flags);
		}

		static void l2x0_flush_all(void)
		static void __l2x0_flush_all(void)
		{
		unsigned long flags;

		/* clean all ways */
		spin_lock_irqsave(&l2x0_lock, flags);
		debug_writel(0x03);
		writel_relaxed(l2x0_way_mask, l2x0_base + L2X0_CLEAN_INV_WAY);
		cache_wait_way(l2x0_base + L2X0_CLEAN_INV_WAY, l2x0_way_mask);
		cache_sync();
		debug_writel(0x00);
		}

		static void l2x0_flush_all(void)
		{
		unsigned long flags;

		/* clean all ways */
		spin_lock_irqsave(&l2x0_lock, flags);
		__l2x0_flush_all();
		spin_unlock_irqrestore(&l2x0_lock, flags);
		}

		@@ -266,7 +271,9 @@ static void l2x0_disable(void)
		unsigned long flags;

		spin_lock_irqsave(&l2x0_lock, flags);
		writel(0, l2x0_base + L2X0_CTRL);
		__l2x0_flush_all();
		writel_relaxed(0, l2x0_base + L2X0_CTRL);
		dsb();
		spin_unlock_irqrestore(&l2x0_lock, flags);
		}

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