[PATCH v3 0/2] mm: PAGE_KERNEL_* fallbacks

[PATCH v3 0/2] mm: PAGE_KERNEL_* fallbacks

[Luis R. Rodriguez]

This is the 3rd iteration for moving PAGE_KERNEL_* fallback
definitions into asm-generic headers. Greg asked for a Changelog
for patch iteration changes, its below.

All these patches have been tested by 0-day.

Questions, and specially flames are greatly appreciated.

v3:

Removed documentation effort to keep tabs on which architectures
currently don't defint the respective PAGE_* flags. Keeping tabs
on this is just not worth it.

Ran a spell checker on all patches :)

v2:

I added a patch for PAGE_KERNEL_EXEC as suggested by Matthew Wilcox.

v1:

I sent out a patch just for dealing witht he fallback mechanism for
PAGE_KERNEL_RO.

Luis R. Rodriguez (2):
  mm: provide a fallback for PAGE_KERNEL_RO for architectures
  mm: provide a fallback for PAGE_KERNEL_EXEC for architectures

 drivers/base/firmware_loader/fallback.c |  5 -----
 include/asm-generic/pgtable.h           | 18 ++++++++++++++++++
 mm/nommu.c                              |  4 ----
 mm/vmalloc.c                            |  4 ----
 4 files changed, 18 insertions(+), 13 deletions(-)

-- 
2.17.0

[PATCH v3 1/2] mm: provide a fallback for PAGE_KERNEL_RO for architectures

[Luis R. Rodriguez]

Some architectures do not define certain PAGE_KERNEL_* flags, this is
either because:

a) The way to implement some of these flags is *not yet ported*, or
b) The architecture *has no way* to describe them

Over time we have accumulated a few PAGE_KERNEL_* fallback work arounds
for architectures in the kernel which do not define them using *relatively
safe* equivalents. Move these scattered fallback hacks into asm-generic.

We start off with PAGE_KERNEL_RO using PAGE_KERNEL as a fallback. This
has been in place on the firmware loader for years. Move the fallback
into the respective asm-generic header.

Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
---
 drivers/base/firmware_loader/fallback.c |  5 -----
 include/asm-generic/pgtable.h           | 14 ++++++++++++++
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
index 358354148dec..36f016b753e0 100644
--- a/drivers/base/firmware_loader/fallback.c
+++ b/drivers/base/firmware_loader/fallback.c
@@ -219,11 +219,6 @@ static ssize_t firmware_loading_show(struct device *dev,
 	return sprintf(buf, "%d\n", loading);
 }
 
-/* Some architectures don't have PAGE_KERNEL_RO */
-#ifndef PAGE_KERNEL_RO
-#define PAGE_KERNEL_RO PAGE_KERNEL
-#endif
-
 /* one pages buffer should be mapped/unmapped only once */
 static int map_fw_priv_pages(struct fw_priv *fw_priv)
 {
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index f59639afaa39..4e310e543fc8 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -1083,6 +1083,20 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
 static inline void init_espfix_bsp(void) { }
 #endif
 
+/*
+ * Architecture PAGE_KERNEL_* fallbacks
+ *
+ * Some architectures don't define certain PAGE_KERNEL_* flags. This is either
+ * because they really don't support them, or the port needs to be updated to
+ * reflect the required functionality. Below are a set of relatively safe
+ * fallbacks, as best effort, which we can count on in lieu of the architectures
+ * not defining them on their own yet.
+ */
+
+#ifndef PAGE_KERNEL_RO
+# define PAGE_KERNEL_RO PAGE_KERNEL
+#endif
+
 #endif /* !__ASSEMBLY__ */
 
 #ifndef io_remap_pfn_range
-- 
2.17.0

[PATCH v3 2/2] mm: provide a fallback for PAGE_KERNEL_EXEC for architectures

[Luis R. Rodriguez]

Some architectures just don't have PAGE_KERNEL_EXEC. The mm/nommu.c
and mm/vmalloc.c code have been using PAGE_KERNEL as a fallback for
years. Move this fallback to asm-generic.

Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
---
 include/asm-generic/pgtable.h | 4 ++++
 mm/nommu.c                    | 4 ----
 mm/vmalloc.c                  | 4 ----
 3 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 4e310e543fc8..81371468ed5a 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -1097,6 +1097,10 @@ static inline void init_espfix_bsp(void) { }
 # define PAGE_KERNEL_RO PAGE_KERNEL
 #endif
 
+#ifndef PAGE_KERNEL_EXEC
+# define PAGE_KERNEL_EXEC PAGE_KERNEL
+#endif
+
 #endif /* !__ASSEMBLY__ */
 
 #ifndef io_remap_pfn_range
diff --git a/mm/nommu.c b/mm/nommu.c
index 13723736d38f..08ad4dcd281d 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -364,10 +364,6 @@ void *vzalloc_node(unsigned long size, int node)
 }
 EXPORT_SYMBOL(vzalloc_node);
 
-#ifndef PAGE_KERNEL_EXEC
-# define PAGE_KERNEL_EXEC PAGE_KERNEL
-#endif
-
 /**
  *	vmalloc_exec  -  allocate virtually contiguous, executable memory
  *	@size:		allocation size
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index ebff729cc956..89543d13e32a 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1920,10 +1920,6 @@ void *vzalloc_node(unsigned long size, int node)
 }
 EXPORT_SYMBOL(vzalloc_node);
 
-#ifndef PAGE_KERNEL_EXEC
-# define PAGE_KERNEL_EXEC PAGE_KERNEL
-#endif
-
 /**
  *	vmalloc_exec  -  allocate virtually contiguous, executable memory
  *	@size:		allocation size
-- 
2.17.0

Re: [PATCH v3 0/2] mm: PAGE_KERNEL_* fallbacks

[Luis R. Rodriguez]

On Thu, May 10, 2018 at 11:55:05AM -0700, Luis R. Rodriguez wrote:
> This is the 3rd iteration for moving PAGE_KERNEL_* fallback
> definitions into asm-generic headers. Greg asked for a Changelog
> for patch iteration changes, its below.
> 
> All these patches have been tested by 0-day.
> 
> Questions, and specially flames are greatly appreciated.

*Poke*

Who's tree should this go through?

  Luis

> 
> v3:
> 
> Removed documentation effort to keep tabs on which architectures
> currently don't defint the respective PAGE_* flags. Keeping tabs
> on this is just not worth it.
> 
> Ran a spell checker on all patches :)
> 
> v2:
> 
> I added a patch for PAGE_KERNEL_EXEC as suggested by Matthew Wilcox.
> 
> v1:
> 
> I sent out a patch just for dealing witht he fallback mechanism for
> PAGE_KERNEL_RO.
> 
> Luis R. Rodriguez (2):
>   mm: provide a fallback for PAGE_KERNEL_RO for architectures
>   mm: provide a fallback for PAGE_KERNEL_EXEC for architectures
> 
>  drivers/base/firmware_loader/fallback.c |  5 -----
>  include/asm-generic/pgtable.h           | 18 ++++++++++++++++++
>  mm/nommu.c                              |  4 ----
>  mm/vmalloc.c                            |  4 ----
>  4 files changed, 18 insertions(+), 13 deletions(-)
> 
> -- 
> 2.17.0
> 
> 

-- 
Do not panic

Re: [PATCH v3 0/2] mm: PAGE_KERNEL_* fallbacks

[Luis R. Rodriguez]

On Wed, May 16, 2018 at 06:44:03PM +0200, Luis R. Rodriguez wrote:
> On Thu, May 10, 2018 at 11:55:05AM -0700, Luis R. Rodriguez wrote:
> > This is the 3rd iteration for moving PAGE_KERNEL_* fallback
> > definitions into asm-generic headers. Greg asked for a Changelog
> > for patch iteration changes, its below.
> > 
> > All these patches have been tested by 0-day.
> > 
> > Questions, and specially flames are greatly appreciated.
> 
> *Poke*

Greg, since this does touch the firmware loader as well, *poke*.

  Luis

Re: [PATCH v3 0/2] mm: PAGE_KERNEL_* fallbacks

[Luis R. Rodriguez]

On Wed, May 23, 2018 at 11:35:51PM +0200, Luis R. Rodriguez wrote:
> On Wed, May 16, 2018 at 06:44:03PM +0200, Luis R. Rodriguez wrote:
> > On Thu, May 10, 2018 at 11:55:05AM -0700, Luis R. Rodriguez wrote:
> > > This is the 3rd iteration for moving PAGE_KERNEL_* fallback
> > > definitions into asm-generic headers. Greg asked for a Changelog
> > > for patch iteration changes, its below.
> > > 
> > > All these patches have been tested by 0-day.
> > > 
> > > Questions, and specially flames are greatly appreciated.
> > 
> > *Poke*
> 
> Greg, since this does touch the firmware loader as well, *poke*.

*Re-re-poke*

  Luis

Re: [PATCH v3 0/2] mm: PAGE_KERNEL_* fallbacks

[Greg KH]

On Wed, May 30, 2018 at 09:55:00PM +0200, Luis R. Rodriguez wrote:
> On Wed, May 23, 2018 at 11:35:51PM +0200, Luis R. Rodriguez wrote:
> > On Wed, May 16, 2018 at 06:44:03PM +0200, Luis R. Rodriguez wrote:
> > > On Thu, May 10, 2018 at 11:55:05AM -0700, Luis R. Rodriguez wrote:
> > > > This is the 3rd iteration for moving PAGE_KERNEL_* fallback
> > > > definitions into asm-generic headers. Greg asked for a Changelog
> > > > for patch iteration changes, its below.
> > > > 
> > > > All these patches have been tested by 0-day.
> > > > 
> > > > Questions, and specially flames are greatly appreciated.
> > > 
> > > *Poke*
> > 
> > Greg, since this does touch the firmware loader as well, *poke*.
> 
> *Re-re-poke*

Hah, they are not for me to take, sorry, that's up to the mm maintainer.

good luck!

greg k-h

Re: [PATCH v3 0/2] mm: PAGE_KERNEL_* fallbacks

[Luis R. Rodriguez]

On Wed, May 30, 2018 at 10:06:08PM +0200, Greg KH wrote:
> On Wed, May 30, 2018 at 09:55:00PM +0200, Luis R. Rodriguez wrote:
> > On Wed, May 23, 2018 at 11:35:51PM +0200, Luis R. Rodriguez wrote:
> > > On Wed, May 16, 2018 at 06:44:03PM +0200, Luis R. Rodriguez wrote:
> > > > On Thu, May 10, 2018 at 11:55:05AM -0700, Luis R. Rodriguez wrote:
> > > > > This is the 3rd iteration for moving PAGE_KERNEL_* fallback
> > > > > definitions into asm-generic headers. Greg asked for a Changelog
> > > > > for patch iteration changes, its below.
> > > > > 
> > > > > All these patches have been tested by 0-day.
> > > > > 
> > > > > Questions, and specially flames are greatly appreciated.
> > > > 
> > > > *Poke*
> > > 
> > > Greg, since this does touch the firmware loader as well, *poke*.
> > 
> > *Re-re-poke*
> 
> Hah, they are not for me to take, sorry, that's up to the mm maintainer.

I'm not sure it is up to mm actually, since this is all
include/asm-generic/pgtable.h it seems this falls onto Arnd.
Its probably *best* mm folks decide though.

Arnd, are you OK if Andrew picks this up if he finds no issues with
the patches?

I'll bouncing copies to Andrew now.

  Luis