[U-Boot] [PATCH 13/22] imx8m: Fix MMU table issue for OPTEE memory

[Peng Fan]

> Subject: Re: [PATCH 13/22] imx8m: Fix MMU table issue for OPTEE memory
> 
> On Fri, 9 Aug 2019 04:15:21 +0000
> Peng Fan <peng.fan at nxp.com> wrote:
> 
> > When running with OPTEE, the MMU table in u-boot does not remove the
> > OPTEE memory from its settings. So ARM speculative prefetch in u-boot
> > may access that OPTEE memory. Due to trust zone is enabled by OPTEE
> > and that memory is set to secure access, then the speculative prefetch
> > will fail and cause various memory issue in u-boot.
> > The fail address register and int_status register in trustzone has
> > logged that speculative access from u-boot.
> >
> > Signed-off-by: Peng Fan <peng.fan at nxp.com>
> > ---
> >  arch/arm/mach-imx/imx8m/soc.c | 20 ++++++++++++++++++--
> >  1 file changed, 18 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm/mach-imx/imx8m/soc.c
> > b/arch/arm/mach-imx/imx8m/soc.c index 5115471eff..dd393b581b
> 100644
> > --- a/arch/arm/mach-imx/imx8m/soc.c
> > +++ b/arch/arm/mach-imx/imx8m/soc.c
> > @@ -112,16 +112,18 @@ static struct mm_region imx8m_mem_map[] = {
> >  		/* DRAM1 */
> >  		.virt = 0x40000000UL,
> >  		.phys = 0x40000000UL,
> > -		.size = 0xC0000000UL,
> > +		.size = PHYS_SDRAM_SIZE,
> 
> Wouldn't this change break other imx8m boards?

No. Currently only i.MX8MQ-EVK landed in upstream. 

> 
> >  		.attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) |
> >  			 PTE_BLOCK_OUTER_SHARE
> > +#ifdef PHYS_SDRAM_2_SIZE
> >  	}, {
> >  		/* DRAM2 */
> >  		.virt = 0x100000000UL,
> >  		.phys = 0x100000000UL,
> > -		.size = 0x040000000UL,
> > +		.size = PHYS_SDRAM_2_SIZE,
> 
> The same here.

No. see above.

> 
> >  		.attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) |
> >  			 PTE_BLOCK_OUTER_SHARE
> > +#endif
> >  	}, {
> >  		/* List terminator */
> >  		0,
> > @@ -130,6 +132,20 @@ static struct mm_region imx8m_mem_map[] = {
> >
> >  struct mm_region *mem_map = imx8m_mem_map;
> >
> > +void enable_caches(void)
> > +{
> > +	/*
> > +	 * If OPTEE runs, remove OPTEE memory from MMU table to
> > +	 * avoid speculative prefetch. OPTEE runs at the top of
> > +	 * the first memory bank
> > +	 */
> > +	if (rom_pointer[1])
> > +		imx8m_mem_map[5].size -= rom_pointer[1];
> > +
> > +	icache_enable();
> > +	dcache_enable();
> 
> In the other patch (which adds board based on imx8mm - in this series
> 22/22) the D and I caches were disabled. Why you add code to enable them
> and those are not enabled on imx8mm EVK board?

The disable is for SPL, I'll enable for SPL.

Thanks,
Peng.

> 
> > +}
> > +
> >  static u32 get_cpu_variant_type(u32 type)  {
> >  	struct ocotp_regs *ocotp = (struct ocotp_regs *)OCOTP_BASE_ADDR;
> 
> 
> 
> Best regards,
> 
> Lukasz Majewski
> 
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