[PATCH] ARM64: mmu: fix mmu_early_enable VA->PA mapping

[Lior Weintraub]

Thanks Ahmad,
I think we can make the init_range function clearer:

void init_range(size_t total_level0_tables)
{
	uint64_t *ttb = get_ttb();
	uint64_t addr = 0;
	while(total_level0_tables--) {
		early_remap_range((void *)addr, L0_XLAT_SIZE, MAP_UNCACHED);
		split_block(ttb,0);
		addr += L0_XLAT_SIZE;
		ttb++;
	}
}

Let me know if you want me to prepare a new patch or you can include it in your warning fix patch.
Cheers,
Lior.

> -----Original Message-----
> From: Ahmad Fatoum <a.fatoum at pengutronix.de>
> Sent: Monday, December 18, 2023 2:43 PM
> To: Lior Weintraub <liorw at pliops.com>; barebox at lists.infradead.org
> Subject: Re: [PATCH] ARM64: mmu: fix mmu_early_enable VA->PA mapping
> 
> CAUTION: External Sender
> 
> On 18.12.23 13:05, Lior Weintraub wrote:
> > From 1b8f4ee9e29e722bbb0b7d0f7fed0ae213ef8637 Mon Sep 17
> 00:00:00 2001
> > From: Lior Weintraub <liorw at pliops.com>
> > Date: Mon, 18 Dec 2023 14:01:16 +0200
> > Subject: [PATCH] ARM64: mmu: fix mmu_early_enable VA->PA mapping
> >
> > Fix the mmu_early_enable function to correctly map 40bits of virtual address
> into physical address with a 1:1 mapping.
> > It uses the init_range function to sets 2 table entries on TTB level0 and then
> fill level1 with the correct 1:1 mapping.
> >
> > Signed-off-by: Lior Weintraub <liorw at pliops.com>
> 
> Tested-by: Ahmad Fatoum <a.fatoum at pengutronix.de> # Qemu ARM64 Virt
> 
> I ran into some warnings when building, for which I sent out a patch
> just now. I think Sascha can squash them if there are no further
> comments.
> 
> Cheers,
> Ahmad
> 
> > ---
> >  arch/arm/cpu/mmu_64.c            | 17 ++++++++++++++++-
> >  arch/arm/cpu/mmu_64.h            | 19 +++++++++++++++++--
> >  arch/arm/include/asm/pgtable64.h |  1 +
> >  3 files changed, 34 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/arm/cpu/mmu_64.c b/arch/arm/cpu/mmu_64.c
> > index c6ea63e655..fe5babbfd9 100644
> > --- a/arch/arm/cpu/mmu_64.c
> > +++ b/arch/arm/cpu/mmu_64.c
> > @@ -294,6 +294,19 @@ void dma_flush_range(void *ptr, size_t size)
> >       v8_flush_dcache_range(start, end);
> >  }
> >
> > +void init_range(void *virt_addr, size_t size)
> > +{
> > +     uint64_t *ttb = get_ttb();
> > +     uint64_t addr = (uint64_t)virt_addr;
> > +     while(size) {
> > +             early_remap_range((void *)addr, L0_XLAT_SIZE, MAP_UNCACHED);
> > +             split_block(ttb,0);
> > +             size -= L0_XLAT_SIZE;
> > +             addr += L0_XLAT_SIZE;
> > +             ttb++;
> > +     }
> > +}
> > +
> >  void mmu_early_enable(unsigned long membase, unsigned long memsize)
> >  {
> >       int el;
> > @@ -308,7 +321,9 @@ void mmu_early_enable(unsigned long membase,
> unsigned long memsize)
> >
> >       memset((void *)ttb, 0, GRANULE_SIZE);
> >
> > -     early_remap_range(0, 1UL << (BITS_PER_VA - 1), MAP_UNCACHED);
> > +     // Assume maximum BITS_PER_PA set to 40 bits.
> > +     // Set 1:1 mapping of VA->PA. So to cover the full 1TB range we need 2
> tables.
> > +     init_range(0, 2*L0_XLAT_SIZE);
> >       early_remap_range(membase, memsize - OPTEE_SIZE, MAP_CACHED);
> >       early_remap_range(membase + memsize - OPTEE_SIZE, OPTEE_SIZE,
> MAP_FAULT);
> >       early_remap_range(PAGE_ALIGN_DOWN((uintptr_t)_stext),
> PAGE_ALIGN(_etext - _stext), MAP_CACHED);
> > diff --git a/arch/arm/cpu/mmu_64.h b/arch/arm/cpu/mmu_64.h
> > index e4d81dace4..e3959e4407 100644
> > --- a/arch/arm/cpu/mmu_64.h
> > +++ b/arch/arm/cpu/mmu_64.h
> > @@ -105,12 +105,27 @@ static inline uint64_t level2mask(int level)
> >       return mask;
> >  }
> >
> > +/**
> > + * @brief Returns the TCR (Translation Control Register) value
> > + *
> > + * @param el - Exception Level
> > + * @param va_bits - Virtual Address bits
> > + * @return uint64_t TCR
> > + */
> >  static inline uint64_t calc_tcr(int el, int va_bits)
> >  {
> > -     u64 ips;
> > -     u64 tcr;
> > +     u64 ips; // Intermediate Physical Address Size
> > +     u64 tcr; // Translation Control Register
> >
> > +#if (BITS_PER_PA == 40)
> >       ips = 2;
> > +#elif (BITS_PER_PA == 36)
> > +     ips = 1;
> > +#elif (BITS_PER_PA == 32)
> > +     ips = 0;
> > +#else
> > +#error "Unsupported"
> > +#endif
> >
> >       if (el == 1)
> >               tcr = (ips << 32) | TCR_EPD1_DISABLE;
> > diff --git a/arch/arm/include/asm/pgtable64.h
> b/arch/arm/include/asm/pgtable64.h
> > index 21dac30cfe..b88ffe6be5 100644
> > --- a/arch/arm/include/asm/pgtable64.h
> > +++ b/arch/arm/include/asm/pgtable64.h
> > @@ -8,6 +8,7 @@
> >
> >  #define VA_START                   0x0
> >  #define BITS_PER_VA                48
> > +#define BITS_PER_PA                40 // Use 40 Physical address bits
> >
> >  /* Granule size of 4KB is being used */
> >  #define GRANULE_SIZE_SHIFT         12
> 
> --
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