MM: Query about different memory types(mem_types)__mmu.c

MM: Query about different memory types(mem_types)__mmu.c

[Sumit Gupta]

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Hi All,

I have been exploring ARM reference manual about ARM weak memory model and
mmu page table setting from some time.
I think i understand different memory types, mmu settings for page/section,
TEX, AP, B, C, S bits well.
My target is to to dig further and fully understand setting of all
parameters for different memory types in ARM
[File mmu.c: "static struct mem_type mem_types"].

But i am not able to find any good source to refer for fully understanding
all below parameters.
Could you please help me to understand mappings for below mem types. If you
can point me to some references which can help me understand more.

Thankyou in advance for your help.


        [MT_DEVICE] = {           /* Strongly ordered / ARMv6 shared device
*/
                .prot_pte       = PROT_PTE_DEVICE | L_PTE_MT_DEV_SHARED |
                                  L_PTE_SHARED,
                .prot_pte_s2    = s2_policy(PROT_PTE_S2_DEVICE) |
                                  s2_policy(L_PTE_S2_MT_DEV_SHARED) |
                                  L_PTE_SHARED,
                .prot_l1        = PMD_TYPE_TABLE,
                .prot_sect      = PROT_SECT_DEVICE | PMD_SECT_S,
                .domain         = DOMAIN_IO,
        },
............
       [MT_MEMORY_RW] = {
                .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
                             L_PTE_XN,
                .prot_l1   = PMD_TYPE_TABLE,
                .prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
                .domain    = DOMAIN_KERNEL,
        },
............
        [MT_MEMORY_DMA_READY] = {
                .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
                                L_PTE_XN,
                .prot_l1   = PMD_TYPE_TABLE,
                .domain    = DOMAIN_KERNEL,
        },

Regards,
Sumit Gupta

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MM: Query about different memory types(mem_types)__mmu.c

[Sumit Gupta]

Hi All,

I have been exploring ARM reference manual about ARM weak memory model
and mmu page table setting from some time.
I think i understand different memory types, mmu settings for
page/section, TEX, AP, B, C, S bits well.
My target is to to dig further and fully understand setting of all
parameters for different memory types in ARM
[File mmu.c: "static struct mem_type mem_types"].

But i am not able to find any good source to refer for fully
understanding all below parameters.
Could you please help me to understand mappings for below mem types.
If you can point me to some references which can help me understand
more.

Thank you in advance for your help.


        [MT_DEVICE] = {           /* Strongly ordered / ARMv6 shared device */
                .prot_pte       = PROT_PTE_DEVICE | L_PTE_MT_DEV_SHARED |
                                  L_PTE_SHARED,
                .prot_pte_s2    = s2_policy(PROT_PTE_S2_DEVICE) |
                                  s2_policy(L_PTE_S2_MT_DEV_SHARED) |
                                  L_PTE_SHARED,
                .prot_l1        = PMD_TYPE_TABLE,
                .prot_sect      = PROT_SECT_DEVICE | PMD_SECT_S,
                .domain         = DOMAIN_IO,
        },
............
       [MT_MEMORY_RW] = {
                .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
                             L_PTE_XN,
                .prot_l1   = PMD_TYPE_TABLE,
                .prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
                .domain    = DOMAIN_KERNEL,
        },
............
        [MT_MEMORY_DMA_READY] = {
                .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
                                L_PTE_XN,
                .prot_l1   = PMD_TYPE_TABLE,
                .domain    = DOMAIN_KERNEL,
        },

Regards,
Sumit Gupta

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