From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Fri, 14 Nov 2014 10:35:28 +0000 Subject: [PATCH] efi: Fix free_end build warning In-Reply-To: References: <1415824050.15847.9.camel@smoke> <20141114102254.GB27963@arm.com> Message-ID: <20141114103528.GC27963@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Nov 14, 2014 at 10:29:59AM +0000, Ard Biesheuvel wrote: > On 14 November 2014 11:22, Will Deacon wrote: > > [Adding original authors] > > > > On Wed, Nov 12, 2014 at 08:27:30PM +0000, Geoff Levand wrote: > >> Initialize the free_end variable to zero. Fixes build warnings > >> like these: > >> > >> arch/arm64/kernel/efi.c: warning: ?free_end? may be used uninitialized in this function > >> > >> Signed-off-by: Geoff Levand > >> --- > >> Got this with the latest arm64/for-next/core branch. Please consider. > >> > >> -Geoff > >> > >> arch/arm64/kernel/efi.c | 1 + > >> 1 file changed, 1 insertion(+) > >> > >> diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c > >> index 4f39a18..83fc53c 100644 > >> --- a/arch/arm64/kernel/efi.c > >> +++ b/arch/arm64/kernel/efi.c > >> @@ -239,6 +239,7 @@ static void __init free_boot_services(void) > >> * want to keep for UEFI. > >> */ > >> > >> + free_end = 0; > >> keep_end = 0; > >> free_start = 0; > > > > Whilst I can't see how free_end gets used uninitialized in this function, > > the code is really hard to read and I'd like to get an Ack from one of the > > people on CC before merging this, just in case GCC is actually telling us > > something useful for a change. > > > > We are planning to remove this code entirely in the 3.20 timeframe. > Freeing boot services will not be necessary any longer once we stop > reserving it in the first place, and I agree that the function is hard > to read. Also, it depends on the UEFI memory map being sorted, which > is not mandated by the spec so we can't actually rely on it. (Even if > it usually is the case) > > So I don't object to this patch, if the warning is bothering people, > but perhaps we can just wait for the warning to go away once the new > stuff lands. Ok, thanks Ard. I think I'll leave it alone for now, then. Will