git: e779604f1d4e - main - Clean up early arm64 pmap code

[Andrew Turner]

Other than simplifying the code it also helps downstream in CheriBSD where init_pt_va could be different sizes based on the kernel configuration. Rather than changing the size of this variable it’s easier to just ask the hardware to perform the translation.

Andrew

> On 24 May 2021, at 11:20, Ronald Klop <ronald-lists at klop.ws> wrote:
> 
> Hi,
> 
> Out of curiosity. What is the expected gain? (Next to simplicity of the code of course.)
> 
> Ronald
> 
> Van: Andrew Turner <andrew at FreeBSD.org>
> Datum: 24 mei 2021 11:44
> Aan: src-committers at FreeBSD.org, dev-commits-src-all at FreeBSD.org, dev-commits-src-main at FreeBSD.org
> Onderwerp: git: e779604f1d4e - main - Clean up early arm64 pmap code
> 
> The branch main has been updated by andrew:
> 
> URL: https://cgit.FreeBSD.org/src/commit/?id=e779604f1d4e5fd0cdf3a9d1bb756b168f97b39c <https://cgit.freebsd.org/src/commit/?id=e779604f1d4e5fd0cdf3a9d1bb756b168f97b39c>
> 
> commit e779604f1d4e5fd0cdf3a9d1bb756b168f97b39c
> Author:     Andrew Turner <andrew at FreeBSD.org>
> AuthorDate: 2021-05-20 06:52:15 +0000
> Commit:     Andrew Turner <andrew at FreeBSD.org>
> CommitDate: 2021-05-24 09:22:19 +0000
> 
>     Clean up early arm64 pmap code
>     
>     Early in the arm64 pmap code we need to translate between a virtual
>     address and a physical address. Rather than manually walking the page
>     table we can ask the hardware to do it for us.
>     
>     Reviewed by:    kib, markj
>     Sponsored by:   Innovate UK
>     Differential Revision: https://reviews.freebsd.org/D30357 <https://reviews.freebsd.org/D30357>
> ---
>  sys/arm64/arm64/locore.S    |  6 ------
>  sys/arm64/arm64/pmap.c      | 28 +++-------------------------
>  sys/arm64/include/vmparam.h |  1 -
>  3 files changed, 3 insertions(+), 32 deletions(-)
> 
> diff --git a/sys/arm64/arm64/locore.S b/sys/arm64/arm64/locore.S
> index f5e6bbd604a5..472a052e9903 100644
> --- a/sys/arm64/arm64/locore.S
> +++ b/sys/arm64/arm64/locore.S
> @@ -735,10 +735,6 @@ ENTRY(abort)
>     b abort
>  END(abort)
>  
> -   .align 3
> -init_pt_va:
> -   .quad pagetable     /* XXX: Keep page tables VA */
> -
>     .section .init_pagetable, "aw", %nobits
>     .align PAGE_SHIFT
>     /*
> @@ -773,8 +769,6 @@ pagetable_end:
>  el2_pagetable:
>     .space  PAGE_SIZE
>  
> -   .globl init_pt_va
> -
>     .align  4
>  initstack:
>     .space  (PAGE_SIZE * KSTACK_PAGES)
> diff --git a/sys/arm64/arm64/pmap.c b/sys/arm64/arm64/pmap.c
> index a3be232a56bf..bc5d228af5ad 100644
> --- a/sys/arm64/arm64/pmap.c
> +++ b/sys/arm64/arm64/pmap.c
> @@ -742,35 +742,13 @@ pmap_resident_count_dec(pmap_t pmap, int count)
>     pmap->pm_stats.resident_count -= count;
>  }
>  
> -static pt_entry_t *
> -pmap_early_page_idx(vm_offset_t l1pt, vm_offset_t va, u_int *l1_slot,
> -    u_int *l2_slot)
> -{
> -   pt_entry_t *l2;
> -   pd_entry_t *l1;
> -
> -   l1 = (pd_entry_t *)l1pt;
> -   *l1_slot = (va >> L1_SHIFT) & Ln_ADDR_MASK;
> -
> -   /* Check locore has used a table L1 map */
> -   KASSERT((l1[*l1_slot] & ATTR_DESCR_MASK) == L1_TABLE,
> -      ("Invalid bootstrap L1 table"));
> -   /* Find the address of the L2 table */
> -   l2 = (pt_entry_t *)init_pt_va;
> -   *l2_slot = pmap_l2_index(va);
> -
> -   return (l2);
> -}
> -
>  static vm_paddr_t
>  pmap_early_vtophys(vm_offset_t l1pt, vm_offset_t va)
>  {
> -   u_int l1_slot, l2_slot;
> -   pt_entry_t *l2;
> -
> -   l2 = pmap_early_page_idx(l1pt, va, &l1_slot, &l2_slot);
> +   vm_paddr_t pa_page;
>  
> -   return ((l2[l2_slot] & ~ATTR_MASK) + (va & L2_OFFSET));
> +   pa_page = arm64_address_translate_s1e1r(va) & PAR_PA_MASK;
> +   return (pa_page | (va & PAR_LOW_MASK));
>  }
>  
>  static vm_offset_t
> diff --git a/sys/arm64/include/vmparam.h b/sys/arm64/include/vmparam.h
> index 4a90c7711e01..a42c68d52887 100644
> --- a/sys/arm64/include/vmparam.h
> +++ b/sys/arm64/include/vmparam.h
> @@ -228,7 +228,6 @@ extern vm_paddr_t dmap_phys_base;
>  extern vm_paddr_t dmap_phys_max;
>  extern vm_offset_t dmap_max_addr;
>  extern vm_offset_t vm_max_kernel_address;
> -extern vm_offset_t init_pt_va;
>  
>  #endif
>  
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