From: Will Deacon Date: Fri, 1 Jul 2011 13:36:19 +0000 (+0100) Subject: ARM: 6987/1: l2x0: fix disabling function to avoid deadlock X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=38a8914f9ac2379293944f613e6ca24b61373de8;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git 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 Signed-off-by: Will Deacon Signed-off-by: Russell King --- 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) 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); }