From mboxrd@z Thu Jan 1 00:00:00 1970 From: pavel@ucw.cz (Pavel Machek) Date: Mon, 16 Nov 2015 13:36:15 +0100 Subject: [PATCH v2 10/11] PM / Hibernate: clean cached pages on architectures that require it In-Reply-To: <5649CB9B.30102@arm.com> References: <1445966960-31724-1-git-send-email-james.morse@arm.com> <1445966960-31724-11-git-send-email-james.morse@arm.com> <20151114202623.GC20429@amd> <5649CB9B.30102@arm.com> Message-ID: <20151116123615.GB9125@amd> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon 2015-11-16 12:27:07, James Morse wrote: > On 14/11/15 20:26, Pavel Machek wrote: > > On Tue 2015-10-27 17:29:19, James Morse wrote: > >> Some architectures require code written to memory as if it were data to be > >> 'cleaned' from any data caches so that the processor can fetch them as new > >> instructions. > >> > >> During resume from hibernate, the snapshot code copies some pages directly, > >> meaning these architectures do not get a chance to perform their cache > >> maintenance. Add a call to flush_icache_range(), which is provided by > >> architectures that require it, to perform the maintenance. > >> > >> This mirrors the kernel's behaviour when loading kernel modules and when > >> mapping executable pages to user space. > >> > >> Signed-off-by: James Morse > > > > Looks reasonable. > > > > Acked-by: Pavel Machek > > Thanks! > > > > >> --- > >> kernel/power/snapshot.c | 4 ++++ > >> 1 file changed, 4 insertions(+) > >> > >> diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c > >> index 5235dd4e1e2f..139fc449ad75 100644 > >> --- a/kernel/power/snapshot.c > >> +++ b/kernel/power/snapshot.c > >> @@ -1196,9 +1197,12 @@ static unsigned int count_data_pages(void) > >> static inline void do_copy_page(long *dst, long *src) > >> { > >> int n; > >> + unsigned long __maybe_unused start = (unsigned long)dst; > > > > Why the "maybe unused"? > > To avoid a build warning on x86_64, and any other architectures that don't > use the arguments in their flush_icache_range() implementation. That's wrong fix, I believe. flush_icache_range() should use their arguments. We should not have all the callers caring about this. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html