On Mon, Dec 16, 2013 at 03:19:06PM +0100, Borislav Petkov wrote: > Date: Mon, 16 Dec 2013 15:19:06 +0100 > From: Borislav Petkov <bp@xxxxxxxxx> > To: "Chen, Gong" <gong.chen@xxxxxxxxxxxxxxx> > Cc: tony.luck@xxxxxxxxx, linux-acpi@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v3] ACPI, APEI: Cleanup alignment related codes for APEI > User-Agent: Mutt/1.5.21 (2010-09-15) > > On Fri, Nov 15, 2013 at 12:45:56AM -0500, Chen, Gong wrote: > > diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c > > index 26311f2..bf30a12 100644 > > --- a/drivers/acpi/apei/erst.c > > +++ b/drivers/acpi/apei/erst.c > > @@ -611,7 +611,7 @@ static void __erst_record_id_cache_compact(void) > > if (entries[i] == APEI_ERST_INVALID_RECORD_ID) > > continue; > > if (wpos != i) > > - memcpy(&entries[wpos], &entries[i], sizeof(entries[i])); > > + entries[wpos] = entries[i]; > > Why is it ok to drop the memcpy here and do a normal access? > > __erst_record_id_cache_add_one still has a memcpy-like access. > > What is the difference with all those accesses to erst_record_id_cache > and why doesn't it need the unaligned helpers? > > This all needs to be explained in detail in the commit message. > > Thanks. > erst record id cache is implemented in the memory to increase the access speed via caching ERST content, so it doesn't matter with firmware access.
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