+ mm-debug_vm_pgtable-dont-use-__p000-directly.patch added to -mm tree

+ mm-debug_vm_pgtable-dont-use-__p000-directly.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm: debug_vm_pgtable: don't use __P000 directly
has been added to the -mm tree.  Its filename is
     mm-debug_vm_pgtable-dont-use-__p000-directly.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-debug_vm_pgtable-dont-use-__p000-directly.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-debug_vm_pgtable-dont-use-__p000-directly.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Guo Ren <guoren@linux.alibaba.com>
Subject: mm: debug_vm_pgtable: don't use __P000 directly

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.

Link: https://lkml.kernel.org/r/20210924060821.1138281-1-guoren@kernel.org
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/debug_vm_pgtable.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/mm/debug_vm_pgtable.c~mm-debug_vm_pgtable-dont-use-__p000-directly
+++ a/mm/debug_vm_pgtable.c
@@ -1104,13 +1104,14 @@ static int __init init_args(struct pgtab
 	/*
 	 * 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;
_

Patches currently in -mm which might be from guoren@linux.alibaba.com are

mm-debug_vm_pgtable-dont-use-__p000-directly.patch

+ mm-debug_vm_pgtable-dont-use-__p000-directly.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm: debug_vm_pgtable: Don't use __P000 directly
has been added to the -mm tree.  Its filename is
     mm-debug_vm_pgtable-dont-use-__p000-directly.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-debug_vm_pgtable-dont-use-__p000-directly.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-debug_vm_pgtable-dont-use-__p000-directly.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Guo Ren <guoren@linux.alibaba.com>
Subject: mm: debug_vm_pgtable: Don't use __P000 directly

The __Pxxx/__Sxxx macros are only for init protection_map[].  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 maybe won't cause bug because hw would deny access with
PROT_NONE permission, but it's not rigorous.

Link: https://lkml.kernel.org/r/20210921201815.284412-1-guoren@kernel.org
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Gavin Shan <gshan@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/debug_vm_pgtable.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/debug_vm_pgtable.c~mm-debug_vm_pgtable-dont-use-__p000-directly
+++ a/mm/debug_vm_pgtable.c
@@ -1104,13 +1104,13 @@ static int __init init_args(struct pgtab
 	/*
 	 * Initialize the debugging data.
 	 *
-	 * __P000 (or even __S000) will help create page table entries with
+	 * __P000 (protection_map[0]) 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;
_

Patches currently in -mm which might be from guoren@linux.alibaba.com are

mm-debug_vm_pgtable-dont-use-__p000-directly.patch