linux-toradex.git/include/linux/vmalloc.h, branch v5.16-rc3

mm/vmalloc: don't allow VM_NO_GUARD on vmap()

2021-11-06T20:30:36+00:00

The vmalloc guard pages are added on top of each allocation, thereby
isolating any two allocations from one another.  The top guard of the
lower allocation is the bottom guard guard of the higher allocation etc.

Therefore VM_NO_GUARD is dangerous; it breaks the basic premise of
isolating separate allocations.

There are only two in-tree users of this flag, neither of which use it
through the exported interface.  Ensure it stays this way.

Link: https://lkml.kernel.org/r/YUMfdA36fuyZ+/xt@hirez.programming.kicks-ass.net
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Christoph Hellwig 
Reviewed-by: David Hildenbrand 
Acked-by: Will Deacon 
Acked-by: Kees Cook 
Cc: Andrey Konovalov 
Cc: Mel Gorman 
Cc: Uladzislau Rezki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmalloc: add __alloc_size attributes for better bounds checking

2021-11-06T20:30:34+00:00

As already done in GrapheneOS, add the __alloc_size attribute for
appropriate vmalloc allocator interfaces, to provide additional hinting
for better bounds checking, assisting CONFIG_FORTIFY_SOURCE and other
compiler optimizations.

Link: https://lkml.kernel.org/r/20210930222704.2631604-7-keescook@chromium.org
Signed-off-by: Kees Cook 
Co-developed-by: Daniel Micay 
Signed-off-by: Daniel Micay 
Cc: Andy Whitcroft 
Cc: Christoph Lameter 
Cc: David Rientjes 
Cc: Dennis Zhou 
Cc: Dwaipayan Ray 
Cc: Joe Perches 
Cc: Joonsoo Kim 
Cc: Lukas Bulwahn 
Cc: Miguel Ojeda 
Cc: Nathan Chancellor 
Cc: Nick Desaulniers 
Cc: Pekka Enberg 
Cc: Tejun Heo 
Cc: Vlastimil Babka 
Cc: Alexandre Bounine 
Cc: Gustavo A. R. Silva 
Cc: Ira Weiny 
Cc: Jing Xiangfeng 
Cc: John Hubbard 
Cc: kernel test robot 
Cc: Matt Porter 
Cc: Randy Dunlap 
Cc: Souptick Joarder 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: move ioremap_page_range to vmalloc.c

2021-09-08T18:50:24+00:00

Patch series "small ioremap cleanups".

The first patch moves a little code around the vmalloc/ioremap boundary
following a bigger move by Nick earlier.  The second enforces
non-executable mapping on ioremap just like we do for vmap.  No driver
currently uses executable mappings anyway, as they should.

This patch (of 2):

This keeps it together with the implementation, and to remove the
vmap_range wrapper.

Link: https://lkml.kernel.org/r/20210824091259.1324527-1-hch@lst.de
Link: https://lkml.kernel.org/r/20210824091259.1324527-2-hch@lst.de
Signed-off-by: Christoph Hellwig 
Reviewed-by: Nicholas Piggin 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: fix spelling mistakes in header files

2021-07-08T18:48:21+00:00

Fix some spelling mistakes in comments:
successfull ==> successful
potentialy ==> potentially
alloced ==> allocated
indicies ==> indices
wont ==> won't
resposible ==> responsible
dirtyness ==> dirtiness
droppped ==> dropped
alread ==> already
occured ==> occurred
interupts ==> interrupts
extention ==> extension
slighly ==> slightly
Dont't ==> Don't

Link: https://lkml.kernel.org/r/20210531034849.9549-2-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei 
Cc: Jerome Glisse 
Cc: Mike Kravetz 
Cc: Dennis Zhou 
Cc: Tejun Heo 
Cc: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmalloc: enable mapping of huge pages at pte level in vmalloc

2021-07-01T03:47:26+00:00

On some architectures like powerpc, there are huge pages that are mapped
at pte level.

Enable it in vmalloc.

For that, architectures can provide arch_vmap_pte_supported_shift() that
returns the shift for pages to map at pte level.

Link: https://lkml.kernel.org/r/2c717e3b1fba1894d890feb7669f83025bfa314d.1620795204.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy 
Cc: Benjamin Herrenschmidt 
Cc: Michael Ellerman 
Cc: Mike Kravetz 
Cc: Mike Rapoport 
Cc: Nicholas Piggin 
Cc: Paul Mackerras 
Cc: Uladzislau Rezki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmalloc: enable mapping of huge pages at pte level in vmap

2021-07-01T03:47:26+00:00

On some architectures like powerpc, there are huge pages that are mapped
at pte level.

Enable it in vmap.

For that, architectures can provide arch_vmap_pte_range_map_size() that
returns the size of pages to map at pte level.

Link: https://lkml.kernel.org/r/fb3ccc73377832ac6708181ec419128a2f98ce36.1620795204.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy 
Cc: Benjamin Herrenschmidt 
Cc: Michael Ellerman 
Cc: Mike Kravetz 
Cc: Mike Rapoport 
Cc: Nicholas Piggin 
Cc: Paul Mackerras 
Cc: Uladzislau Rezki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmalloc: add vmalloc_no_huge

2021-06-25T02:40:53+00:00

Patch series "mm: add vmalloc_no_huge and use it", v4.

Add vmalloc_no_huge() and export it, so modules can allocate memory with
small pages.

Use the newly added vmalloc_no_huge() in KVM on s390 to get around a
hardware limitation.

This patch (of 2):

Commit 121e6f3258fe3 ("mm/vmalloc: hugepage vmalloc mappings") added
support for hugepage vmalloc mappings, it also added the flag
VM_NO_HUGE_VMAP for __vmalloc_node_range to request the allocation to be
performed with 0-order non-huge pages.

This flag is not accessible when calling vmalloc, the only option is to
call directly __vmalloc_node_range, which is not exported.

This means that a module can't vmalloc memory with small pages.

Case in point: KVM on s390x needs to vmalloc a large area, and it needs
to be mapped with non-huge pages, because of a hardware limitation.

This patch adds the function vmalloc_no_huge, which works like vmalloc,
but it is guaranteed to always back the mapping using small pages.  This
new function is exported, therefore it is usable by modules.

[akpm@linux-foundation.org: whitespace fixes, per Christoph]

Link: https://lkml.kernel.org/r/20210614132357.10202-1-imbrenda@linux.ibm.com
Link: https://lkml.kernel.org/r/20210614132357.10202-2-imbrenda@linux.ibm.com
Fixes: 121e6f3258fe3 ("mm/vmalloc: hugepage vmalloc mappings")
Signed-off-by: Claudio Imbrenda 
Reviewed-by: Uladzislau Rezki (Sony) 
Acked-by: Nicholas Piggin 
Reviewed-by: David Hildenbrand 
Acked-by: David Rientjes 
Cc: Uladzislau Rezki (Sony) 
Cc: Catalin Marinas 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Christoph Hellwig 
Cc: Cornelia Huck 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: fix typos in comments

2021-05-07T07:26:35+00:00

Fix ~94 single-word typos in locking code comments, plus a few
very obvious grammar mistakes.

Link: https://lkml.kernel.org/r/20210322212624.GA1963421@gmail.com
Link: https://lore.kernel.org/r/20210322205203.GB1959563@gmail.com
Signed-off-by: Ingo Molnar 
Reviewed-by: Matthew Wilcox (Oracle) 
Reviewed-by: Randy Dunlap 
Cc: Bhaskar Chowdhury 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmalloc: remove vwrite()

2021-05-07T07:26:34+00:00

The last user (/dev/kmem) is gone. Let's drop it.

Link: https://lkml.kernel.org/r/20210324102351.6932-4-david@redhat.com
Signed-off-by: David Hildenbrand 
Acked-by: Michal Hocko 
Cc: Linus Torvalds 
Cc: Greg Kroah-Hartman 
Cc: Hillf Danton 
Cc: Matthew Wilcox 
Cc: Oleksiy Avramchenko 
Cc: Steven Rostedt 
Cc: Minchan Kim 
Cc: huang ying 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

drivers/char: remove /dev/kmem for good

2021-05-07T07:26:34+00:00

Patch series "drivers/char: remove /dev/kmem for good".

Exploring /dev/kmem and /dev/mem in the context of memory hot(un)plug and
memory ballooning, I started questioning the existence of /dev/kmem.

Comparing it with the /proc/kcore implementation, it does not seem to be
able to deal with things like

a) Pages unmapped from the direct mapping (e.g., to be used by secretmem)
  -> kern_addr_valid(). virt_addr_valid() is not sufficient.

b) Special cases like gart aperture memory that is not to be touched
  -> mem_pfn_is_ram()

Unless I am missing something, it's at least broken in some cases and might
fault/crash the machine.

Looks like its existence has been questioned before in 2005 and 2010 [1],
after ~11 additional years, it might make sense to revive the discussion.

CONFIG_DEVKMEM is only enabled in a single defconfig (on purpose or by
mistake?).  All distributions disable it: in Ubuntu it has been disabled
for more than 10 years, in Debian since 2.6.31, in Fedora at least
starting with FC3, in RHEL starting with RHEL4, in SUSE starting from
15sp2, and OpenSUSE has it disabled as well.

1) /dev/kmem was popular for rootkits [2] before it got disabled
   basically everywhere. Ubuntu documents [3] "There is no modern user of
   /dev/kmem any more beyond attackers using it to load kernel rootkits.".
   RHEL documents in a BZ [5] "it served no practical purpose other than to
   serve as a potential security problem or to enable binary module drivers
   to access structures/functions they shouldn't be touching"

2) /proc/kcore is a decent interface to have a controlled way to read
   kernel memory for debugging puposes. (will need some extensions to
   deal with memory offlining/unplug, memory ballooning, and poisoned
   pages, though)

3) It might be useful for corner case debugging [1]. KDB/KGDB might be a
   better fit, especially, to write random memory; harder to shoot
   yourself into the foot.

4) "Kernel Memory Editor" [4] hasn't seen any updates since 2000 and seems
   to be incompatible with 64bit [1]. For educational purposes,
   /proc/kcore might be used to monitor value updates -- or older
   kernels can be used.

5) It's broken on arm64, and therefore, completely disabled there.

Looks like it's essentially unused and has been replaced by better
suited interfaces for individual tasks (/proc/kcore, KDB/KGDB). Let's
just remove it.

[1] https://lwn.net/Articles/147901/
[2] https://www.linuxjournal.com/article/10505
[3] https://wiki.ubuntu.com/Security/Features#A.2Fdev.2Fkmem_disabled
[4] https://sourceforge.net/projects/kme/
[5] https://bugzilla.redhat.com/show_bug.cgi?id=154796

Link: https://lkml.kernel.org/r/20210324102351.6932-1-david@redhat.com
Link: https://lkml.kernel.org/r/20210324102351.6932-2-david@redhat.com
Signed-off-by: David Hildenbrand 
Acked-by: Michal Hocko 
Acked-by: Kees Cook 
Cc: Linus Torvalds 
Cc: Greg Kroah-Hartman 
Cc: "Alexander A. Klimov" 
Cc: Alexander Viro 
Cc: Alexandre Belloni 
Cc: Andrew Lunn 
Cc: Andrey Zhizhikin 
Cc: Arnd Bergmann 
Cc: Benjamin Herrenschmidt 
Cc: Brian Cain 
Cc: Christian Borntraeger 
Cc: Christophe Leroy 
Cc: Chris Zankel 
Cc: Corentin Labbe 
Cc: "David S. Miller" 
Cc: "Eric W. Biederman" 
Cc: Geert Uytterhoeven 
Cc: Gerald Schaefer 
Cc: Greentime Hu 
Cc: Gregory Clement 
Cc: Heiko Carstens 
Cc: Helge Deller 
Cc: Hillf Danton 
Cc: huang ying 
Cc: Ingo Molnar 
Cc: Ivan Kokshaysky 
Cc: "James E.J. Bottomley" 
Cc: James Troup 
Cc: Jiaxun Yang 
Cc: Jonas Bonn 
Cc: Jonathan Corbet 
Cc: Kairui Song 
Cc: Krzysztof Kozlowski 
Cc: Kuninori Morimoto 
Cc: Liviu Dudau 
Cc: Lorenzo Pieralisi 
Cc: Luc Van Oostenryck 
Cc: Luis Chamberlain 
Cc: Matthew Wilcox 
Cc: Matt Turner 
Cc: Max Filippov 
Cc: Michael Ellerman 
Cc: Mike Rapoport 
Cc: Mikulas Patocka 
Cc: Minchan Kim 
Cc: Niklas Schnelle 
Cc: Oleksiy Avramchenko 
Cc: openrisc@lists.librecores.org
Cc: Palmer Dabbelt 
Cc: Paul Mackerras 
Cc: "Pavel Machek (CIP)" 
Cc: Pavel Machek 
Cc: "Peter Zijlstra (Intel)" 
Cc: Pierre Morel 
Cc: Randy Dunlap 
Cc: Richard Henderson 
Cc: Rich Felker 
Cc: Robert Richter 
Cc: Rob Herring 
Cc: Russell King 
Cc: Sam Ravnborg 
Cc: Sebastian Andrzej Siewior 
Cc: Sebastian Hesselbarth 
Cc: sparclinux@vger.kernel.org
Cc: Stafford Horne 
Cc: Stefan Kristiansson 
Cc: Steven Rostedt 
Cc: Sudeep Holla 
Cc: Theodore Dubois 
Cc: Thomas Bogendoerfer 
Cc: Thomas Gleixner 
Cc: Vasily Gorbik 
Cc: Viresh Kumar 
Cc: William Cohen 
Cc: Xiaoming Ni 
Cc: Yoshinori Sato 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds