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ARM: cache: do not crash when the MMU isn't yet setup 

Drivers currently cannot implement explicit cache handling and rely on
running the same code before and after mmu_initcall() without crashing.

Depending on the chosen config options, the cache functions are not yet
setup and using them early on ends in a null pointer dereference.

The RPi's mailbox driver is such a case; it requires cache handling once
the MMU is fully set up and yet the RPi setup needs to use the driver to
get the memory size before mem_initcall() and hence mmu_initcall().

Fix this by checking the cache_fns pointer before dereferencing it.

Signed-off-by: Andre Heider <a.heider@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Andre Heider 2013-10-19 14:20:47 +02:00 committed by Sascha Hauer
parent 5611ccb042
commit 0fdd91d92b
1 changed files with 12 additions and 6 deletions
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18
arch/arm/cpu/cache.c
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@ -41,32 +41,38 @@ DEFINE_CPU_FNS(v7)
void __dma_clean_range(unsigned long start, unsigned long end)
{
cache_fns->dma_clean_range(start, end);
if (cache_fns)
cache_fns->dma_clean_range(start, end);
}
void __dma_flush_range(unsigned long start, unsigned long end)
{
cache_fns->dma_flush_range(start, end);
if (cache_fns)
cache_fns->dma_flush_range(start, end);
}
void __dma_inv_range(unsigned long start, unsigned long end)
{
cache_fns->dma_inv_range(start, end);
if (cache_fns)
cache_fns->dma_inv_range(start, end);
}
void __mmu_cache_on(void)
{
cache_fns->mmu_cache_on();
if (cache_fns)
cache_fns->mmu_cache_on();
}
void __mmu_cache_off(void)
{
cache_fns->mmu_cache_off();
if (cache_fns)
cache_fns->mmu_cache_off();
}
void __mmu_cache_flush(void)
{
cache_fns->mmu_cache_flush();
if (cache_fns)
cache_fns->mmu_cache_flush();
}
int arm_set_cache_functions(void)