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[PATCH v8 3/6] arm64: ptdump: Use the mask from the state structure

Sebastian Ene posted 6 patches 1 year, 5 months ago
There is a newer version of this series
[PATCH v8 3/6] arm64: ptdump: Use the mask from the state structure
Posted by Sebastian Ene 1 year, 5 months ago 
Printing the descriptor attributes requires accessing a mask which has a
different set of attributes for stage-2. In preparation for adding support
for the stage-2 pagetables dumping, use the mask from the local context
and not from the globally defined pg_level array. Store a pointer to
the pg_level array in the ptdump state structure. This will allow us to
extract the mask which is wrapped in the pg_level array and use it for
descriptor parsing in the note_page.

Signed-off-by: Sebastian Ene <sebastianene@google.com>
---
 arch/arm64/include/asm/ptdump.h |  1 +
 arch/arm64/mm/ptdump.c          | 13 ++++++++-----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h
index bd5d3ee3e8dc..71a7ed01153a 100644
--- a/arch/arm64/include/asm/ptdump.h
+++ b/arch/arm64/include/asm/ptdump.h
@@ -44,6 +44,7 @@ struct ptdump_pg_level {
  */
 struct ptdump_pg_state {
 	struct ptdump_state ptdump;
+	struct ptdump_pg_level *pg_level;
 	struct seq_file *seq;
 	const struct addr_marker *marker;
 	const struct mm_struct *mm;
diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c
index 404751fd30fe..ca53ef274a8b 100644
--- a/arch/arm64/mm/ptdump.c
+++ b/arch/arm64/mm/ptdump.c
@@ -117,7 +117,7 @@ static const struct ptdump_prot_bits pte_bits[] = {
 	}
 };
 
-static struct ptdump_pg_level pg_level[] __ro_after_init = {
+static struct ptdump_pg_level kernel_pg_levels[] __ro_after_init = {
 	{ /* pgd */
 		.name	= "PGD",
 		.bits	= pte_bits,
@@ -192,6 +192,7 @@ void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,
 	       u64 val)
 {
 	struct ptdump_pg_state *st = container_of(pt_st, struct ptdump_pg_state, ptdump);
+	struct ptdump_pg_level *pg_level = st->pg_level;
 	static const char units[] = "KMGTPE";
 	u64 prot = 0;
 
@@ -262,6 +263,7 @@ void ptdump_walk(struct seq_file *s, struct ptdump_info *info)
 		.seq = s,
 		.marker = info->markers,
 		.mm = info->mm,
+		.pg_level = &kernel_pg_levels[0],
 		.level = -1,
 		.ptdump = {
 			.note_page = note_page,
@@ -279,10 +281,10 @@ static void __init ptdump_initialize(void)
 {
 	unsigned i, j;
 
-	for (i = 0; i < ARRAY_SIZE(pg_level); i++)
-		if (pg_level[i].bits)
-			for (j = 0; j < pg_level[i].num; j++)
-				pg_level[i].mask |= pg_level[i].bits[j].mask;
+	for (i = 0; i < ARRAY_SIZE(kernel_pg_levels); i++)
+		if (kernel_pg_levels[i].bits)
+			for (j = 0; j < kernel_pg_levels[i].num; j++)
+				kernel_pg_levels[i].mask |= kernel_pg_levels[i].bits[j].mask;
 }
 
 static struct ptdump_info kernel_ptdump_info __ro_after_init = {
@@ -297,6 +299,7 @@ bool ptdump_check_wx(void)
 			{ 0, NULL},
 			{ -1, NULL},
 		},
+		.pg_level = &kernel_pg_levels[0],
 		.level = -1,
 		.check_wx = true,
 		.ptdump = {
-- 
2.46.0.184.g6999bdac58-goog
Re: [PATCH v8 3/6] arm64: ptdump: Use the mask from the state structure
Posted by Marc Zyngier 1 year, 5 months ago 
On Fri, 16 Aug 2024 13:39:03 +0100,
Sebastian Ene <sebastianene@google.com> wrote:
> 
> Printing the descriptor attributes requires accessing a mask which has a
> different set of attributes for stage-2. In preparation for adding support
> for the stage-2 pagetables dumping, use the mask from the local context
> and not from the globally defined pg_level array. Store a pointer to
> the pg_level array in the ptdump state structure. This will allow us to
> extract the mask which is wrapped in the pg_level array and use it for
> descriptor parsing in the note_page.
> 
> Signed-off-by: Sebastian Ene <sebastianene@google.com>
> ---
>  arch/arm64/include/asm/ptdump.h |  1 +
>  arch/arm64/mm/ptdump.c          | 13 ++++++++-----
>  2 files changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h
> index bd5d3ee3e8dc..71a7ed01153a 100644
> --- a/arch/arm64/include/asm/ptdump.h
> +++ b/arch/arm64/include/asm/ptdump.h
> @@ -44,6 +44,7 @@ struct ptdump_pg_level {
>   */
>  struct ptdump_pg_state {
>  	struct ptdump_state ptdump;
> +	struct ptdump_pg_level *pg_level;
>  	struct seq_file *seq;
>  	const struct addr_marker *marker;
>  	const struct mm_struct *mm;
> diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c
> index 404751fd30fe..ca53ef274a8b 100644
> --- a/arch/arm64/mm/ptdump.c
> +++ b/arch/arm64/mm/ptdump.c
> @@ -117,7 +117,7 @@ static const struct ptdump_prot_bits pte_bits[] = {
>  	}
>  };
>  
> -static struct ptdump_pg_level pg_level[] __ro_after_init = {
> +static struct ptdump_pg_level kernel_pg_levels[] __ro_after_init = {

Do you actually need this sort of renaming? Given that it is static,
this looks like some slightly abusive repainting which isn't warranted
here.

I also didn't understand the commit message: you're not tracking any
mask here, but a page table level. You are also not using it for
anything yet, see below.


>  	{ /* pgd */
>  		.name	= "PGD",
>  		.bits	= pte_bits,
> @@ -192,6 +192,7 @@ void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,
>  	       u64 val)
>  {
>  	struct ptdump_pg_state *st = container_of(pt_st, struct ptdump_pg_state, ptdump);
> +	struct ptdump_pg_level *pg_level = st->pg_level;

This is what I mean. What is this pg_level used for?

>  	static const char units[] = "KMGTPE";
>  	u64 prot = 0;
>  
> @@ -262,6 +263,7 @@ void ptdump_walk(struct seq_file *s, struct ptdump_info *info)
>  		.seq = s,
>  		.marker = info->markers,
>  		.mm = info->mm,
> +		.pg_level = &kernel_pg_levels[0],
>  		.level = -1,
>  		.ptdump = {
>  			.note_page = note_page,
> @@ -279,10 +281,10 @@ static void __init ptdump_initialize(void)
>  {
>  	unsigned i, j;
>  
> -	for (i = 0; i < ARRAY_SIZE(pg_level); i++)
> -		if (pg_level[i].bits)
> -			for (j = 0; j < pg_level[i].num; j++)
> -				pg_level[i].mask |= pg_level[i].bits[j].mask;
> +	for (i = 0; i < ARRAY_SIZE(kernel_pg_levels); i++)
> +		if (kernel_pg_levels[i].bits)
> +			for (j = 0; j < kernel_pg_levels[i].num; j++)
> +				kernel_pg_levels[i].mask |= kernel_pg_levels[i].bits[j].mask;
>  }
>  
>  static struct ptdump_info kernel_ptdump_info __ro_after_init = {
> @@ -297,6 +299,7 @@ bool ptdump_check_wx(void)
>  			{ 0, NULL},
>  			{ -1, NULL},
>  		},
> +		.pg_level = &kernel_pg_levels[0],
>  		.level = -1,
>  		.check_wx = true,
>  		.ptdump = {

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.
Re: [PATCH v8 3/6] arm64: ptdump: Use the mask from the state structure
Posted by Sebastian Ene 1 year, 5 months ago 
On Tue, Aug 20, 2024 at 02:49:04PM +0100, Marc Zyngier wrote:
> On Fri, 16 Aug 2024 13:39:03 +0100,
> Sebastian Ene <sebastianene@google.com> wrote:
> > 
> > Printing the descriptor attributes requires accessing a mask which has a
> > different set of attributes for stage-2. In preparation for adding support
> > for the stage-2 pagetables dumping, use the mask from the local context
> > and not from the globally defined pg_level array. Store a pointer to
> > the pg_level array in the ptdump state structure. This will allow us to
> > extract the mask which is wrapped in the pg_level array and use it for
> > descriptor parsing in the note_page.
> > 
> > Signed-off-by: Sebastian Ene <sebastianene@google.com>
> > ---
> >  arch/arm64/include/asm/ptdump.h |  1 +
> >  arch/arm64/mm/ptdump.c          | 13 ++++++++-----
> >  2 files changed, 9 insertions(+), 5 deletions(-)
> > 
> > diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h
> > index bd5d3ee3e8dc..71a7ed01153a 100644
> > --- a/arch/arm64/include/asm/ptdump.h
> > +++ b/arch/arm64/include/asm/ptdump.h
> > @@ -44,6 +44,7 @@ struct ptdump_pg_level {
> >   */
> >  struct ptdump_pg_state {
> >  	struct ptdump_state ptdump;
> > +	struct ptdump_pg_level *pg_level;
> >  	struct seq_file *seq;
> >  	const struct addr_marker *marker;
> >  	const struct mm_struct *mm;
> > diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c
> > index 404751fd30fe..ca53ef274a8b 100644
> > --- a/arch/arm64/mm/ptdump.c
> > +++ b/arch/arm64/mm/ptdump.c
> > @@ -117,7 +117,7 @@ static const struct ptdump_prot_bits pte_bits[] = {
> >  	}
> >  };
> >  
> > -static struct ptdump_pg_level pg_level[] __ro_after_init = {
> > +static struct ptdump_pg_level kernel_pg_levels[] __ro_after_init = {

Hi Marc,

 
> Do you actually need this sort of renaming? Given that it is static,
> this looks like some slightly abusive repainting which isn't warranted
> here.

I applied Will's suggestion from
https://lore.kernel.org/all/20240705111229.GB9231@willie-the-truck/
>
> 
> I also didn't understand the commit message: you're not tracking any
> mask here, but a page table level. You are also not using it for
> anything yet, see below.

and I missed updating the commit message.

> 
> 
> >  	{ /* pgd */
> >  		.name	= "PGD",
> >  		.bits	= pte_bits,
> > @@ -192,6 +192,7 @@ void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,
> >  	       u64 val)
> >  {
> >  	struct ptdump_pg_state *st = container_of(pt_st, struct ptdump_pg_state, ptdump);
> > +	struct ptdump_pg_level *pg_level = st->pg_level;
> 
> This is what I mean. What is this pg_level used for?

I make use of it to extract the name based on the level. The suggestion
that Will made allowed me to keep the code with less changes.

Thanks,
Seb

> 
> >  	static const char units[] = "KMGTPE";
> >  	u64 prot = 0;
> >  
> > @@ -262,6 +263,7 @@ void ptdump_walk(struct seq_file *s, struct ptdump_info *info)
> >  		.seq = s,
> >  		.marker = info->markers,
> >  		.mm = info->mm,
> > +		.pg_level = &kernel_pg_levels[0],
> >  		.level = -1,
> >  		.ptdump = {
> >  			.note_page = note_page,
> > @@ -279,10 +281,10 @@ static void __init ptdump_initialize(void)
> >  {
> >  	unsigned i, j;
> >  
> > -	for (i = 0; i < ARRAY_SIZE(pg_level); i++)
> > -		if (pg_level[i].bits)
> > -			for (j = 0; j < pg_level[i].num; j++)
> > -				pg_level[i].mask |= pg_level[i].bits[j].mask;
> > +	for (i = 0; i < ARRAY_SIZE(kernel_pg_levels); i++)
> > +		if (kernel_pg_levels[i].bits)
> > +			for (j = 0; j < kernel_pg_levels[i].num; j++)
> > +				kernel_pg_levels[i].mask |= kernel_pg_levels[i].bits[j].mask;
> >  }
> >  
> >  static struct ptdump_info kernel_ptdump_info __ro_after_init = {
> > @@ -297,6 +299,7 @@ bool ptdump_check_wx(void)
> >  			{ 0, NULL},
> >  			{ -1, NULL},
> >  		},
> > +		.pg_level = &kernel_pg_levels[0],
> >  		.level = -1,
> >  		.check_wx = true,
> >  		.ptdump = {
> 
> Thanks,
> 
> 	M.
> 
> -- 
> Without deviation from the norm, progress is not possible.
Re: [PATCH v8 3/6] arm64: ptdump: Use the mask from the state structure
Posted by Marc Zyngier 1 year, 5 months ago 
On Tue, 20 Aug 2024 15:13:27 +0100,
Sebastian Ene <sebastianene@google.com> wrote:
> 
> On Tue, Aug 20, 2024 at 02:49:04PM +0100, Marc Zyngier wrote:
> > On Fri, 16 Aug 2024 13:39:03 +0100,
> > Sebastian Ene <sebastianene@google.com> wrote:
> > > 
> > > Printing the descriptor attributes requires accessing a mask which has a
> > > different set of attributes for stage-2. In preparation for adding support
> > > for the stage-2 pagetables dumping, use the mask from the local context
> > > and not from the globally defined pg_level array. Store a pointer to
> > > the pg_level array in the ptdump state structure. This will allow us to
> > > extract the mask which is wrapped in the pg_level array and use it for
> > > descriptor parsing in the note_page.
> > > 
> > > Signed-off-by: Sebastian Ene <sebastianene@google.com>
> > > ---
> > >  arch/arm64/include/asm/ptdump.h |  1 +
> > >  arch/arm64/mm/ptdump.c          | 13 ++++++++-----
> > >  2 files changed, 9 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h
> > > index bd5d3ee3e8dc..71a7ed01153a 100644
> > > --- a/arch/arm64/include/asm/ptdump.h
> > > +++ b/arch/arm64/include/asm/ptdump.h
> > > @@ -44,6 +44,7 @@ struct ptdump_pg_level {
> > >   */
> > >  struct ptdump_pg_state {
> > >  	struct ptdump_state ptdump;
> > > +	struct ptdump_pg_level *pg_level;
> > >  	struct seq_file *seq;
> > >  	const struct addr_marker *marker;
> > >  	const struct mm_struct *mm;
> > > diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c
> > > index 404751fd30fe..ca53ef274a8b 100644
> > > --- a/arch/arm64/mm/ptdump.c
> > > +++ b/arch/arm64/mm/ptdump.c
> > > @@ -117,7 +117,7 @@ static const struct ptdump_prot_bits pte_bits[] = {
> > >  	}
> > >  };
> > >  
> > > -static struct ptdump_pg_level pg_level[] __ro_after_init = {
> > > +static struct ptdump_pg_level kernel_pg_levels[] __ro_after_init = {
> 
> Hi Marc,
> 
>  
> > Do you actually need this sort of renaming? Given that it is static,
> > this looks like some slightly abusive repainting which isn't warranted
> > here.
> 
> I applied Will's suggestion from
> https://lore.kernel.org/all/20240705111229.GB9231@willie-the-truck/
> >
> > 
> > I also didn't understand the commit message: you're not tracking any
> > mask here, but a page table level. You are also not using it for
> > anything yet, see below.
> 
> and I missed updating the commit message.
> 
> > 
> > 
> > >  	{ /* pgd */
> > >  		.name	= "PGD",
> > >  		.bits	= pte_bits,
> > > @@ -192,6 +192,7 @@ void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,
> > >  	       u64 val)
> > >  {
> > >  	struct ptdump_pg_state *st = container_of(pt_st, struct ptdump_pg_state, ptdump);
> > > +	struct ptdump_pg_level *pg_level = st->pg_level;
> > 
> > This is what I mean. What is this pg_level used for?
> 
> I make use of it to extract the name based on the level. The suggestion
> that Will made allowed me to keep the code with less changes.

Err, I see that now. It'd be good if you described what actually
happens, because it is almost impossible to understand it from reading
the patch.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.
Re: [PATCH v8 3/6] arm64: ptdump: Use the mask from the state structure
Posted by Sebastian Ene 1 year, 5 months ago 
On Tue, Aug 20, 2024 at 03:25:13PM +0100, Marc Zyngier wrote:
> On Tue, 20 Aug 2024 15:13:27 +0100,
> Sebastian Ene <sebastianene@google.com> wrote:
> > 
> > On Tue, Aug 20, 2024 at 02:49:04PM +0100, Marc Zyngier wrote:
> > > On Fri, 16 Aug 2024 13:39:03 +0100,
> > > Sebastian Ene <sebastianene@google.com> wrote:
> > > > 
> > > > Printing the descriptor attributes requires accessing a mask which has a
> > > > different set of attributes for stage-2. In preparation for adding support
> > > > for the stage-2 pagetables dumping, use the mask from the local context
> > > > and not from the globally defined pg_level array. Store a pointer to
> > > > the pg_level array in the ptdump state structure. This will allow us to
> > > > extract the mask which is wrapped in the pg_level array and use it for
> > > > descriptor parsing in the note_page.
> > > > 
> > > > Signed-off-by: Sebastian Ene <sebastianene@google.com>
> > > > ---
> > > >  arch/arm64/include/asm/ptdump.h |  1 +
> > > >  arch/arm64/mm/ptdump.c          | 13 ++++++++-----
> > > >  2 files changed, 9 insertions(+), 5 deletions(-)
> > > > 
> > > > diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h
> > > > index bd5d3ee3e8dc..71a7ed01153a 100644
> > > > --- a/arch/arm64/include/asm/ptdump.h
> > > > +++ b/arch/arm64/include/asm/ptdump.h
> > > > @@ -44,6 +44,7 @@ struct ptdump_pg_level {
> > > >   */
> > > >  struct ptdump_pg_state {
> > > >  	struct ptdump_state ptdump;
> > > > +	struct ptdump_pg_level *pg_level;
> > > >  	struct seq_file *seq;
> > > >  	const struct addr_marker *marker;
> > > >  	const struct mm_struct *mm;
> > > > diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c
> > > > index 404751fd30fe..ca53ef274a8b 100644
> > > > --- a/arch/arm64/mm/ptdump.c
> > > > +++ b/arch/arm64/mm/ptdump.c
> > > > @@ -117,7 +117,7 @@ static const struct ptdump_prot_bits pte_bits[] = {
> > > >  	}
> > > >  };
> > > >  
> > > > -static struct ptdump_pg_level pg_level[] __ro_after_init = {
> > > > +static struct ptdump_pg_level kernel_pg_levels[] __ro_after_init = {
> > 
> > Hi Marc,
> > 
> >  
> > > Do you actually need this sort of renaming? Given that it is static,
> > > this looks like some slightly abusive repainting which isn't warranted
> > > here.
> > 
> > I applied Will's suggestion from
> > https://lore.kernel.org/all/20240705111229.GB9231@willie-the-truck/
> > >
> > > 
> > > I also didn't understand the commit message: you're not tracking any
> > > mask here, but a page table level. You are also not using it for
> > > anything yet, see below.
> > 
> > and I missed updating the commit message.
> > 
> > > 
> > > 
> > > >  	{ /* pgd */
> > > >  		.name	= "PGD",
> > > >  		.bits	= pte_bits,
> > > > @@ -192,6 +192,7 @@ void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,
> > > >  	       u64 val)
> > > >  {
> > > >  	struct ptdump_pg_state *st = container_of(pt_st, struct ptdump_pg_state, ptdump);
> > > > +	struct ptdump_pg_level *pg_level = st->pg_level;
> > > 
> > > This is what I mean. What is this pg_level used for?
> > 
> > I make use of it to extract the name based on the level. The suggestion
> > that Will made allowed me to keep the code with less changes.
> 
> Err, I see that now. It'd be good if you described what actually
> happens, because it is almost impossible to understand it from reading
> the patch.

Yes, let me re-write the commit message in the next version,

Thanks,
Seb

> 
> Thanks,
> 
> 	M.
> 
> -- 
> Without deviation from the norm, progress is not possible.

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