[PATCH V2] mm: debug_vm_pgtable: Don't use __P000 directly

[PATCH V2] mm: debug_vm_pgtable: Don't use __P000 directly

[guoren]

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>

---

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;
-- 
2.25.1

Re: [PATCH V2] mm: debug_vm_pgtable: Don't use __P000 directly

[Anshuman Khandual]

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;
> 

Re: [PATCH V2] mm: debug_vm_pgtable: Don't use __P000 directly

[Guo Ren]

Got it, thanks!

On Mon, Sep 27, 2021 at 10:16 AM Anshuman Khandual
<anshuman.khandual@arm.com> wrote:
>
>
>
> 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;
> >



-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/