Re: [PATCH v2 12/18] ARM64: mmu: add dynamic optee memory mapping support

[Sascha Hauer <sha@pengutronix.de>]

On Thu, Jan 18, 2024 at 10:13:43AM +0100, Marco Felsch wrote:
> On 24-01-17, Sascha Hauer wrote:
> > On Tue, Jan 16, 2024 at 06:07:32PM +0100, Marco Felsch wrote:
> > > Use the dynamic optee memory base address for the early mapping if
> > > possible and fallback to the static mapping if the query failed.
> > > 
> > > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> > > ---
> > >  arch/arm/cpu/mmu_64.c      | 14 ++++++++++++--
> > >  arch/arm/mach-imx/esdctl.c |  4 ++++
> > >  common/Makefile            |  2 +-
> > >  3 files changed, 17 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/arch/arm/cpu/mmu_64.c b/arch/arm/cpu/mmu_64.c
> > > index 84f45bc2c3c1..27fd15ea1233 100644
> > > --- a/arch/arm/cpu/mmu_64.c
> > > +++ b/arch/arm/cpu/mmu_64.c
> > > @@ -20,6 +20,7 @@
> > >  #include <memory.h>
> > >  #include <asm/system_info.h>
> > >  #include <linux/pagemap.h>
> > > +#include <tee/optee.h>
> > >  
> > >  #include "mmu_64.h"
> > >  
> > > @@ -310,6 +311,7 @@ static void init_range(size_t total_level0_tables)
> > >  void mmu_early_enable(unsigned long membase, unsigned long memsize)
> > >  {
> > >  	int el;
> > > +	u64 optee_membase;
> > >  	unsigned long ttb = arm_mem_ttb(membase + memsize);
> > >  
> > >  	pr_debug("enabling MMU, ttb @ 0x%08lx\n", ttb);
> > > @@ -326,8 +328,16 @@ void mmu_early_enable(unsigned long membase, unsigned long memsize)
> > >  	 * Set 1:1 mapping of VA->PA. So to cover the full 1TB range we need 2 tables.
> > >  	 */
> > >  	init_range(2);
> > > -	early_remap_range(membase, memsize - OPTEE_SIZE, MAP_CACHED);
> > > -	early_remap_range(membase + memsize - OPTEE_SIZE, OPTEE_SIZE, MAP_FAULT);
> > > +
> > > +	if (optee_get_membase(&optee_membase)) {
> > > +		/* Fallback and place OP-TEE at the memory end region */
> > > +		early_remap_range(membase, memsize - OPTEE_SIZE, MAP_CACHED);
> > > +		early_remap_range(membase + memsize - OPTEE_SIZE, OPTEE_SIZE, MAP_FAULT);
> > > +	} else {
> > > +		early_remap_range(membase, memsize, MAP_CACHED);
> > > +		early_remap_range(optee_membase, OPTEE_SIZE, MAP_FAULT);
> > > +	}
> > 
> > You could replace the above with:
> > 
> > 	early_remap_range(membase, memsize, MAP_CACHED);
> > 
> > 	optee_membase = membase + memsize - OPTEE_SIZE;
> > 	optee_get_membase(&optee_membase);
> > 	early_remap_range(optee_membase, OPTEE_SIZE, MAP_FAULT);
> 
> Nice catch, thanks a lot. How about:
> 
>   	early_remap_range(membase, memsize, MAP_CACHED);
>   
>   	if (optee_get_membase(&optee_membase))
> 		optee_membase = membase + memsize - OPTEE_SIZE;
>   	early_remap_range(optee_membase, OPTEE_SIZE, MAP_FAULT);

Also fine.

Sascha


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