Messages in this thread | | | Subject | Re: [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range | From | Zhang Rui <> | Date | Fri, 02 Sep 2011 10:18:56 +0800 |
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On Thu, 2011-09-01 at 20:28 +0800, Matt Fleming wrote: > On Thu, 2011-09-01 at 16:14 +0800, Zhang Rui wrote: > > On Thu, 2011-09-01 at 14:55 +0800, Zhang, Rui wrote: > > > From: Zhang Rui <rui.zhang@intel.com> > > > Date: Wed, 31 Aug 2011 09:59:01 +0800 > > > Subject: Do not use __pa() to get the physical address of an ioremapped memory range. > > > > > > set_memory_uc uses __pa() to translate the virtual address to the physical address. > > > This breaks a EFI_MEMORY_MAPPED_IO memory region in my case as it was ioremapped first. > > > > > oops, wrong patch was attached. > > > > here is the correct patch. > > > > From: Zhang Rui <rui.zhang@intel.com> > > Date: Wed, 31 Aug 2011 09:59:01 +0800 > > Subject: Do not use __pa() to get the physical address of an ioremapped memory range. > > > > set_memory_uc uses __pa() to translate the virtual address to the physical address. > > This breaks a EFI_MEMORY_MAPPED_IO memory region in my case as it was ioremapped first. > > Hmm.. does anyone know why we ioremap_cache() the memory on > CONFIG_X86_32 instead of ioremap_nocache()?
Perhaps this is because not all the memory range need ioremap_nocache(), e.g. EFI_BOOT_SERVICES_CODE, EFI_BOOT_SERVICES_DATA, etc?
So the current logic is to use ioremap_cache for all of them first, and then set all the non-write-back memory ranges to uncacheable.
> In the case of > EFI_MEMORY_MAPPED_IO the memory really needs to be uncached. Then if > we've ioremap'd the memory we should skip set_memory_uc() altogether, > no? > In the beginning, I tried to fix efi_ioremap, i.e. use ioremap_nocache for EFI_MEMORY_MAPPED_IO and ioremap_cache for others. But I'm not sure if that is the right FIX, as I don't know if there might be other memory ranges that also need to be set to uncached.
thanks, rui
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