| Message ID | 20210921201815.284412-1-guoren@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: debug_vm_pgtable: Don't use __P000 directly | expand |
Hello Guo, On 9/22/21 1:48 AM, guoren@kernel.org wrote: > From: Guo Ren <guoren@linux.alibaba.com> > > The __Pxxx/__Sxxx macros are only for init protection_map[]. All s/init protection_map[]/protection_map[] int/ Or rephrase with something similar. > usage of them in linux should come from protection_map array. Agreed. > > Becasue a lot of architectures would re-initilize protection_map[] s/Becasue/Because/ ./scripts/checkpatch.pl ./0001-mm-debug_vm_pgtable-Don-t-use-__P000-directly.patch WARNING: 'Becasue' may be misspelled - perhaps 'Because'? #9: Becasue a lot of architectures would re-initilize protection_map[] ^^^^^^^ total: 0 errors, 1 warnings, 15 lines checked > array, eg: x86-mem_encrypt, m68k-motorola, mips, arm, sparc. > > Using __P000 maybe won't cause bug because hw would deny access Not very clear. Could you please rephrase. > with PROT_NONE permission, but it's not rigorous. Agreed. > > Signed-off-by: Guo Ren <guoren@linux.alibaba.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > --- > mm/debug_vm_pgtable.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c > index 1403639302e4..a6ebbf6e53dd 100644 > --- a/mm/debug_vm_pgtable.c > +++ b/mm/debug_vm_pgtable.c > @@ -1104,13 +1104,13 @@ 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 > + * __P000 (protection_map[0]) will help create page table entries with Please just replace __P000 and __S000 with protection_map[0] and protection_map[8] respectively. Also reformat this comment section if required. > * 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; > With the above changes in place. Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
On Fri, Sep 24, 2021 at 11:30 AM Anshuman Khandual <anshuman.khandual@arm.com> wrote: > > Hello Guo, > > On 9/22/21 1:48 AM, guoren@kernel.org wrote: > > From: Guo Ren <guoren@linux.alibaba.com> > > > > The __Pxxx/__Sxxx macros are only for init protection_map[]. All > > s/init protection_map[]/protection_map[] int/ ^^^ Okay, protection_map[] init > > Or rephrase with something similar. > > > usage of them in linux should come from protection_map array. > > Agreed. > > > > > Becasue a lot of architectures would re-initilize protection_map[] > > s/Becasue/Because/ > > ./scripts/checkpatch.pl ./0001-mm-debug_vm_pgtable-Don-t-use-__P000-directly.patch > WARNING: 'Becasue' may be misspelled - perhaps 'Because'? > #9: > Becasue a lot of architectures would re-initilize protection_map[] > ^^^^^^^ > > total: 0 errors, 1 warnings, 15 lines checked I would use checkpatch.pl next time, thx. > > > array, eg: x86-mem_encrypt, m68k-motorola, mips, arm, sparc. > > > > Using __P000 maybe won't cause bug because hw would deny access > > Not very clear. Could you please rephrase. Using __P000 directly wouldn't equal protection_map[0] in many arches, but the reason why it didn't cause the problem is the hardware ignores the other bits when prot-attribute is denied. > > > with PROT_NONE permission, but it's not rigorous. > > Agreed. > > > > > Signed-off-by: Guo Ren <guoren@linux.alibaba.com> > > Cc: Andrew Morton <akpm@linux-foundation.org> > > --- > > mm/debug_vm_pgtable.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c > > index 1403639302e4..a6ebbf6e53dd 100644 > > --- a/mm/debug_vm_pgtable.c > > +++ b/mm/debug_vm_pgtable.c > > @@ -1104,13 +1104,13 @@ 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 > > + * __P000 (protection_map[0]) will help create page table entries with > > Please just replace __P000 and __S000 with protection_map[0] and > protection_map[8] respectively. Also reformat this comment section > if required. > > > * 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; > > > > With the above changes in place. > > Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index 1403639302e4..a6ebbf6e53dd 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -1104,13 +1104,13 @@ 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 + * __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;