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SubjectRe: [PATCH V2] mm: debug_vm_pgtable: Don't use __P000 directly
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On 9/24/21 11:38 AM, guoren@kernel.org wrote:
> From: Guo Ren <guoren@linux.alibaba.com>
>
> The __Pxxx/__Sxxx macros are only for protection_map[] init. All
> usage of them in linux should come from protection_map array.
>
> Because a lot of architectures would re-initilize protection_map[]
> array, eg: x86-mem_encrypt, m68k-motorola, mips, arm, sparc.
>
> Using __P000 is not rigorous.
>
> Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> Reviewed-by: Andrew Morton <akpm@linux-foundation.org>

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>


>
> ---
>
> Changes since V2:
> - s/init protection_map[]/protection_map[] init/
> - s/Becasue/Because/
> - Remove unclear part
> - Replace __P000 and __S000 with protection_map[0] and
> protection_map[8]
> ---
> mm/debug_vm_pgtable.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
> index 1403639302e4..228e3954b90c 100644
> --- a/mm/debug_vm_pgtable.c
> +++ b/mm/debug_vm_pgtable.c
> @@ -1104,13 +1104,14 @@ static int __init init_args(struct pgtable_debug_args *args)
> /*
> * Initialize the debugging data.
> *
> - * __P000 (or even __S000) will help create page table entries with
> - * PROT_NONE permission as required for pxx_protnone_tests().
> + * protection_map[0] (or even protection_map[8]) will help create
> + * page table entries with PROT_NONE permission as required for
> + * pxx_protnone_tests().
> */
> memset(args, 0, sizeof(*args));
> args->vaddr = get_random_vaddr();
> args->page_prot = vm_get_page_prot(VMFLAGS);
> - args->page_prot_none = __P000;
> + args->page_prot_none = protection_map[0];
> args->is_contiguous_page = false;
> args->pud_pfn = ULONG_MAX;
> args->pmd_pfn = ULONG_MAX;
>

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