[U-Boot] [PATCH v2 3/4] api: FreeBSD: flush cache before starting loader/kernel

[Emmanuel Vadot <manu@bidouilliste.com>]

On Tue, 17 Jan 2017 21:13:51 +0100
Alexander Graf <agraf@suse.de> wrote:

> 
> 
> On 17/01/2017 16:50, Emmanuel Vadot wrote:
> > From: Warner Losh <imp@freebsd.org>
> >
> > FreeBSD loader(8) just loaded code to some random location that may
> > contain stale icache entries.
> > FreeBSD Kernel needs the icache and dcache flushed.
> > Before running either one of them, flush the icache and dcache.
> >
> > Signed-off-by: Emmanuel Vadot <manu@bidouilliste.com>
> 
> Is there any downside to doing the flush always? I would prefer to not 
> conditionalize it on CONFIG_FREEBSD.

 I don't think there is any downside.

> > ---
> >  api/api.c  | 5 +++++
> >  cmd/boot.c | 5 +++++
> >  cmd/elf.c  | 8 +++++++-
> >  3 files changed, 17 insertions(+), 1 deletion(-)
> >
> > diff --git a/api/api.c b/api/api.c
> > index 8a1433af78..cc25deca09 100644
> > --- a/api/api.c
> > +++ b/api/api.c
> > @@ -290,6 +290,11 @@ static int API_dev_close(va_list ap)
> >  	if (!err)
> >  		di->state = DEV_STA_CLOSED;
> >
> > +#ifdef CONFIG_FREEBSD
> > +	flush_dcache_all();
> > +	invalidate_icache_all();
> > +#endif
> > +
> >  	return err;
> >  }
> >
> > diff --git a/cmd/boot.c b/cmd/boot.c
> > index 72f2cf362d..a1a91fbf0a 100644
> > --- a/cmd/boot.c
> > +++ b/cmd/boot.c
> > @@ -19,6 +19,11 @@ __attribute__((weak))
> >  unsigned long do_go_exec(ulong (*entry)(int, char * const []), int argc,
> >  				 char * const argv[])
> >  {
> > +#ifdef CONFIG_FREEBSD
> > +	flush_dcache_all();
> > +	invalidate_icache_all();
> > +#endif
> > +
> >  	return entry (argc, argv);
> >  }
> >
> > diff --git a/cmd/elf.c b/cmd/elf.c
> > index 5190cc6c0f..b2827fa042 100644
> > --- a/cmd/elf.c
> > +++ b/cmd/elf.c
> > @@ -109,6 +109,7 @@ static unsigned long do_bootelf_exec(ulong (*entry)(int, char * const[]),
> >  {
> >  	unsigned long ret;
> >
> > +#ifndef CONFIG_FREEBSD
> >  	/*
> >  	 * QNX images require the data cache is disabled.
> >  	 * Data cache is already flushed, so just turn it off.
> > @@ -116,15 +117,20 @@ static unsigned long do_bootelf_exec(ulong (*entry)(int, char * const[]),
> >  	int dcache = dcache_status();
> >  	if (dcache)
> >  		dcache_disable();
> 
> Can FreeBSD boot with dcache disabled? Is there some way we can 
> determine what payload we have from the elf header?
> 
> 
> Alex

 FreeBSD can boot with dcache disabled (our loader and kernel can)
 I'm not sure I get your other question, sorry.

-- 
Emmanuel Vadot <manu@bidouilliste.com> <manu@freebsd.org>