ARC: IOC: panic if both IOC and ZONE_HIGHMEM enabled (2b720e99) · Commits · 戴 / test

arch/arc/mm/cache.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -1144,6 +1144,19 @@ noinline void __init arc_ioc_setup(void)
		{
		unsigned int ioc_base, mem_sz;

		/*
		* As for today we don't support both IOC and ZONE_HIGHMEM enabled
		* simultaneously. This happens because as of today IOC aperture covers
		* only ZONE_NORMAL (low mem) and any dma transactions outside this
		* region won't be HW coherent.
		* If we want to use both IOC and ZONE_HIGHMEM we can use
		* bounce_buffer to handle dma transactions to HIGHMEM.
		* Also it is possible to modify dma_direct cache ops or increase IOC
		* aperture size if we are planning to use HIGHMEM without PAE.
		*/
		if (IS_ENABLED(CONFIG_HIGHMEM))
		panic("IOC and HIGHMEM can't be used simultaneously");

		/* Flush + invalidate + disable L1 dcache */
		__dc_disable();