Hi,
On 6/13/25 09:58, Sascha Hauer wrote:
> Map the remainder of the memory explicitly with two level page tables. This is
> the place where barebox proper ends at. In barebox proper we'll remap the code
> segments readonly/executable and the ro segments readonly/execute never. For
> this
> we need the memory being mapped pagewise. We can't do the split up from
> section
> wise mapping to pagewise mapping later because that would require us to do
> a break-before-make sequence which we can't do when barebox proper is running
> at the location being remapped.
>
> Signed-off-by: Sascha Hauer <s.ha...@pengutronix.de>
> ---
> arch/arm/cpu/mmu_64.c | 68
> +++++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 66 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/cpu/mmu_64.c b/arch/arm/cpu/mmu_64.c
> index
> 440258fa767735a4537abd71030a5540813fc443..dc81c1da6add38b59b44a9a4e247ab51ebc2692e
> 100644
> --- a/arch/arm/cpu/mmu_64.c
> +++ b/arch/arm/cpu/mmu_64.c
> @@ -10,6 +10,7 @@
> #include <init.h>
> #include <mmu.h>
> #include <errno.h>
> +#include <range.h>
> #include <zero_page.h>
> #include <linux/sizes.h>
> #include <asm/memory.h>
> @@ -172,6 +173,56 @@ static void create_sections(uint64_t virt, uint64_t
> phys, uint64_t size,
> tlb_invalidate();
> }
>
> +/*
> + * like create_sections(), but this one creates pages instead of sections
> + */
> +static void create_pages(uint64_t phys, uint64_t size, uint64_t attr)
Why not add a parameter to create_sections? Code looks nearly
equivalent, except that we would tweak the inner most condition.
Looks good otherwise:
Reviewed-by: Ahmad Fatoum <a.fat...@pengutronix.de>
Cheers,
Ahmad
> +{
> + uint64_t virt = phys;
> + uint64_t *ttb = get_ttb();
> + uint64_t block_size;
> + uint64_t block_shift;
> + uint64_t *pte;
> + uint64_t idx;
> + uint64_t addr;
> + uint64_t *table;
> + uint64_t type;
> + int level;
> +
> + addr = virt;
> +
> + attr &= ~PTE_TYPE_MASK;
> +
> + size = PAGE_ALIGN(size);
> +
> + while (size) {
> + table = ttb;
> + for (level = 0; level < 4; level++) {
> + block_shift = level2shift(level);
> + idx = (addr & level2mask(level)) >> block_shift;
> + block_size = (1ULL << block_shift);
> +
> + pte = table + idx;
> +
> + if (level == 3) {
> + type = PTE_TYPE_PAGE;
> + *pte = phys | attr | type;
> + addr += block_size;
> + phys += block_size;
> + size -= block_size;
> + break;
> + } else {
> + split_block(pte, level);
> + }
> +
> + table = get_level_table(pte);
> + }
> +
> + }
> +
> + tlb_invalidate();
> +}
> +
> static size_t granule_size(int level)
> {
> switch (level) {
> @@ -410,6 +461,7 @@ void mmu_early_enable(unsigned long membase, unsigned
> long memsize, unsigned lon
> {
> int el;
> u64 optee_membase;
> + unsigned long barebox_size;
> unsigned long ttb = arm_mem_ttb(membase + memsize);
>
> if (get_cr() & CR_M)
> @@ -432,12 +484,24 @@ void mmu_early_enable(unsigned long membase, unsigned
> long memsize, unsigned lon
>
> early_remap_range(membase, memsize, MAP_CACHED);
>
> - if (optee_get_membase(&optee_membase))
> + if (optee_get_membase(&optee_membase)) {
> optee_membase = membase + memsize - OPTEE_SIZE;
>
> + barebox_size = optee_membase - barebox_start;
> +
> + create_pages(optee_membase - barebox_size, barebox_size,
> + get_pte_attrs(ARCH_MAP_CACHED_RWX));
> + } else {
> + barebox_size = membase + memsize - barebox_start;
> +
> + create_pages(membase + memsize - barebox_size, barebox_size,
> + get_pte_attrs(ARCH_MAP_CACHED_RWX));
> + }
> +
> early_remap_range(optee_membase, OPTEE_SIZE, MAP_FAULT);
>
> - early_remap_range(PAGE_ALIGN_DOWN((uintptr_t)_stext), PAGE_ALIGN(_etext
> - _stext), MAP_CACHED);
> + early_remap_range(PAGE_ALIGN_DOWN((uintptr_t)_stext), PAGE_ALIGN(_etext
> - _stext),
> + MAP_CACHED);
>
> mmu_enable();
> }
>
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