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authorWill Deacon <will.deacon@arm.com>2011-07-01 09:36:19 -0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-07-06 15:48:08 -0400
commit38a8914f9ac2379293944f613e6ca24b61373de8 (patch)
tree2e414d49cb202c610899b8871626fb9eda580452 /arch/arm/mm
parent186dcaa448c0a7a99933efac2af225fc4fe82c53 (diff)
ARM: 6987/1: l2x0: fix disabling function to avoid deadlock
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>
Diffstat (limited to 'arch/arm/mm')
-rw-r--r--arch/arm/mm/cache-l2x0.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
index ef59099a5463..44c086710d2b 100644
--- a/arch/arm/mm/cache-l2x0.c
+++ b/arch/arm/mm/cache-l2x0.c
@@ -120,17 +120,22 @@ static void l2x0_cache_sync(void)
120 spin_unlock_irqrestore(&l2x0_lock, flags); 120 spin_unlock_irqrestore(&l2x0_lock, flags);
121} 121}
122 122
123static void l2x0_flush_all(void) 123static void __l2x0_flush_all(void)
124{ 124{
125 unsigned long flags;
126
127 /* clean all ways */
128 spin_lock_irqsave(&l2x0_lock, flags);
129 debug_writel(0x03); 125 debug_writel(0x03);
130 writel_relaxed(l2x0_way_mask, l2x0_base + L2X0_CLEAN_INV_WAY); 126 writel_relaxed(l2x0_way_mask, l2x0_base + L2X0_CLEAN_INV_WAY);
131 cache_wait_way(l2x0_base + L2X0_CLEAN_INV_WAY, l2x0_way_mask); 127 cache_wait_way(l2x0_base + L2X0_CLEAN_INV_WAY, l2x0_way_mask);
132 cache_sync(); 128 cache_sync();
133 debug_writel(0x00); 129 debug_writel(0x00);
130}
131
132static void l2x0_flush_all(void)
133{
134 unsigned long flags;
135
136 /* clean all ways */
137 spin_lock_irqsave(&l2x0_lock, flags);
138 __l2x0_flush_all();
134 spin_unlock_irqrestore(&l2x0_lock, flags); 139 spin_unlock_irqrestore(&l2x0_lock, flags);
135} 140}
136 141
@@ -266,7 +271,9 @@ static void l2x0_disable(void)
266 unsigned long flags; 271 unsigned long flags;
267 272
268 spin_lock_irqsave(&l2x0_lock, flags); 273 spin_lock_irqsave(&l2x0_lock, flags);
269 writel(0, l2x0_base + L2X0_CTRL); 274 __l2x0_flush_all();
275 writel_relaxed(0, l2x0_base + L2X0_CTRL);
276 dsb();
270 spin_unlock_irqrestore(&l2x0_lock, flags); 277 spin_unlock_irqrestore(&l2x0_lock, flags);
271} 278}
272 279