lkml.org 
[lkml]   [2015]   [May]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/3] ARM: cache-l2c: Add flag to skip cache unlocking
On Tue, May 12, 2015 at 12:17:29AM +0200, Sjoerd Simons wrote:
> The L2C cache should only be unlocked when the cache is setup to allow
> that. In the common case the l2x0 driver sets up the cache for that to
> be the case (e.g. setting L310_AUX_CTRL_NS_LOCKDOWN on L2C-310), making
> unlock safe. However when a secure firmware is in use, it may not be
> possible for the L2c to be configured that way making unlocking unsafe.
>
> To handle that case add a flag to skip unlocking the cache for machine
> where this can't be done safely.
>
> Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
> ---
> arch/arm/include/asm/outercache.h | 1 +
> arch/arm/mm/cache-l2x0.c | 4 +++-
> 2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/include/asm/outercache.h b/arch/arm/include/asm/outercache.h
> index 563b92f..d07ca82 100644
> --- a/arch/arm/include/asm/outercache.h
> +++ b/arch/arm/include/asm/outercache.h
> @@ -39,6 +39,7 @@ struct outer_cache_fns {
> /* This is an ARM L2C thing */
> void (*write_sec)(unsigned long, unsigned);
> void (*configure)(const struct l2x0_regs *);
> + bool skip_unlock;
> };
>
> extern struct outer_cache_fns outer_cache;
> diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
> index e309c8f..fff7888 100644
> --- a/arch/arm/mm/cache-l2x0.c
> +++ b/arch/arm/mm/cache-l2x0.c
> @@ -136,7 +136,8 @@ static void l2c_enable(void __iomem *base, u32 aux, unsigned num_lock)
> l2x0_saved_regs.aux_ctrl = aux;
> l2c_configure(base);
>
> - l2c_unlock(base, num_lock);
> + if (!outer_cache.skip_unlock)
> + l2c_unlock(base, num_lock);

I think we can do better here. If the non-secure lockdown access bit has
been set, then proceed with the unlock:

if (readl_relaxed(base + L2X0_AUX_CTRL) & L310_AUX_CTRL_NS_LOCKDOWN)
l2c_unlock(base, num_lock);

I don't see any need to add a flag for this. This also eliminates your
second patch.

--
FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up
according to speedtest.net.


\
 
 \ /
  Last update: 2015-05-12 01:01    [W:0.047 / U:4.324 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site