<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/arch/alpha/include, branch v4.9.103</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>futex: Remove duplicated code and fix undefined behaviour</title>
<updated>2018-05-19T08:27:00+00:00</updated>
<author>
<name>Jiri Slaby</name>
<email>jslaby@suse.cz</email>
</author>
<published>2017-08-24T07:31:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=81da9f87ad9d5b77014f0d11946ffbc887bdec70'/>
<id>81da9f87ad9d5b77014f0d11946ffbc887bdec70</id>
<content type='text'>
commit 30d6e0a4190d37740e9447e4e4815f06992dd8c3 upstream.

There is code duplicated over all architecture's headers for
futex_atomic_op_inuser. Namely op decoding, access_ok check for uaddr,
and comparison of the result.

Remove this duplication and leave up to the arches only the needed
assembly which is now in arch_futex_atomic_op_inuser.

This effectively distributes the Will Deacon's arm64 fix for undefined
behaviour reported by UBSAN to all architectures. The fix was done in
commit 5f16a046f8e1 (arm64: futex: Fix undefined behaviour with
FUTEX_OP_OPARG_SHIFT usage). Look there for an example dump.

And as suggested by Thomas, check for negative oparg too, because it was
also reported to cause undefined behaviour report.

Note that s390 removed access_ok check in d12a29703 ("s390/uaccess:
remove pointless access_ok() checks") as access_ok there returns true.
We introduce it back to the helper for the sake of simplicity (it gets
optimized away anyway).

Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Acked-by: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
Acked-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt; (powerpc)
Acked-by: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt; [s390]
Acked-by: Chris Metcalf &lt;cmetcalf@mellanox.com&gt; [for tile]
Reviewed-by: Darren Hart (VMware) &lt;dvhart@infradead.org&gt;
Reviewed-by: Will Deacon &lt;will.deacon@arm.com&gt; [core/arm64]
Cc: linux-mips@linux-mips.org
Cc: Rich Felker &lt;dalias@libc.org&gt;
Cc: linux-ia64@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: peterz@infradead.org
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: sparclinux@vger.kernel.org
Cc: Jonas Bonn &lt;jonas@southpole.se&gt;
Cc: linux-s390@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&gt;
Cc: linux-hexagon@vger.kernel.org
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: "James E.J. Bottomley" &lt;jejb@parisc-linux.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Matt Turner &lt;mattst88@gmail.com&gt;
Cc: linux-snps-arc@lists.infradead.org
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: linux-xtensa@linux-xtensa.org
Cc: Stefan Kristiansson &lt;stefan.kristiansson@saunalahti.fi&gt;
Cc: openrisc@lists.librecores.org
Cc: Ivan Kokshaysky &lt;ink@jurassic.park.msu.ru&gt;
Cc: Stafford Horne &lt;shorne@gmail.com&gt;
Cc: linux-arm-kernel@lists.infradead.org
Cc: Richard Henderson &lt;rth@twiddle.net&gt;
Cc: Chris Zankel &lt;chris@zankel.net&gt;
Cc: Michal Simek &lt;monstr@monstr.eu&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: linux-parisc@vger.kernel.org
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: Richard Kuo &lt;rkuo@codeaurora.org&gt;
Cc: linux-alpha@vger.kernel.org
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Cc: linuxppc-dev@lists.ozlabs.org
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Link: http://lkml.kernel.org/r/20170824073105.3901-1-jslaby@suse.cz
Cc: Ben Hutchings &lt;ben.hutchings@codethink.co.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 30d6e0a4190d37740e9447e4e4815f06992dd8c3 upstream.

There is code duplicated over all architecture's headers for
futex_atomic_op_inuser. Namely op decoding, access_ok check for uaddr,
and comparison of the result.

Remove this duplication and leave up to the arches only the needed
assembly which is now in arch_futex_atomic_op_inuser.

This effectively distributes the Will Deacon's arm64 fix for undefined
behaviour reported by UBSAN to all architectures. The fix was done in
commit 5f16a046f8e1 (arm64: futex: Fix undefined behaviour with
FUTEX_OP_OPARG_SHIFT usage). Look there for an example dump.

And as suggested by Thomas, check for negative oparg too, because it was
also reported to cause undefined behaviour report.

Note that s390 removed access_ok check in d12a29703 ("s390/uaccess:
remove pointless access_ok() checks") as access_ok there returns true.
We introduce it back to the helper for the sake of simplicity (it gets
optimized away anyway).

Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Acked-by: Russell King &lt;rmk+kernel@armlinux.org.uk&gt;
Acked-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt; (powerpc)
Acked-by: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt; [s390]
Acked-by: Chris Metcalf &lt;cmetcalf@mellanox.com&gt; [for tile]
Reviewed-by: Darren Hart (VMware) &lt;dvhart@infradead.org&gt;
Reviewed-by: Will Deacon &lt;will.deacon@arm.com&gt; [core/arm64]
Cc: linux-mips@linux-mips.org
Cc: Rich Felker &lt;dalias@libc.org&gt;
Cc: linux-ia64@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: peterz@infradead.org
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: sparclinux@vger.kernel.org
Cc: Jonas Bonn &lt;jonas@southpole.se&gt;
Cc: linux-s390@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: Yoshinori Sato &lt;ysato@users.sourceforge.jp&gt;
Cc: linux-hexagon@vger.kernel.org
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: "James E.J. Bottomley" &lt;jejb@parisc-linux.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Matt Turner &lt;mattst88@gmail.com&gt;
Cc: linux-snps-arc@lists.infradead.org
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: linux-xtensa@linux-xtensa.org
Cc: Stefan Kristiansson &lt;stefan.kristiansson@saunalahti.fi&gt;
Cc: openrisc@lists.librecores.org
Cc: Ivan Kokshaysky &lt;ink@jurassic.park.msu.ru&gt;
Cc: Stafford Horne &lt;shorne@gmail.com&gt;
Cc: linux-arm-kernel@lists.infradead.org
Cc: Richard Henderson &lt;rth@twiddle.net&gt;
Cc: Chris Zankel &lt;chris@zankel.net&gt;
Cc: Michal Simek &lt;monstr@monstr.eu&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: linux-parisc@vger.kernel.org
Cc: Vineet Gupta &lt;vgupta@synopsys.com&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: Richard Kuo &lt;rkuo@codeaurora.org&gt;
Cc: linux-alpha@vger.kernel.org
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Cc: linuxppc-dev@lists.ozlabs.org
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Link: http://lkml.kernel.org/r/20170824073105.3901-1-jslaby@suse.cz
Cc: Ben Hutchings &lt;ben.hutchings@codethink.co.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>alpha: uapi: Add support for __SANE_USERSPACE_TYPES__</title>
<updated>2017-09-07T06:35:40+00:00</updated>
<author>
<name>Ben Hutchings</name>
<email>ben@decadent.org.uk</email>
</author>
<published>2015-10-01T00:35:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d4e7dfda905ec08abd303068f22afd714dbda8d6'/>
<id>d4e7dfda905ec08abd303068f22afd714dbda8d6</id>
<content type='text'>
commit cec80d82142ab25c71eee24b529cfeaf17c43062 upstream.

This fixes compiler errors in perf such as:

tests/attr.c: In function 'store_event':
tests/attr.c:66:27: error: format '%llu' expects argument of type 'long long unsigned int', but argument 6 has type '__u64 {aka long unsigned int}' [-Werror=format=]
  snprintf(path, PATH_MAX, "%s/event-%d-%llu-%d", dir,
                           ^

Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Tested-by: Michael Cree &lt;mcree@orcon.net.nz&gt;
Signed-off-by: Matt Turner &lt;mattst88@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit cec80d82142ab25c71eee24b529cfeaf17c43062 upstream.

This fixes compiler errors in perf such as:

tests/attr.c: In function 'store_event':
tests/attr.c:66:27: error: format '%llu' expects argument of type 'long long unsigned int', but argument 6 has type '__u64 {aka long unsigned int}' [-Werror=format=]
  snprintf(path, PATH_MAX, "%s/event-%d-%llu-%d", dir,
                           ^

Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
Tested-by: Michael Cree &lt;mcree@orcon.net.nz&gt;
Signed-off-by: Matt Turner &lt;mattst88@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs</title>
<updated>2016-10-15T01:19:05+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-10-15T01:19:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b26b5ef5ec7eab0e1d84c5b281e87b2f2a5e0586'/>
<id>b26b5ef5ec7eab0e1d84c5b281e87b2f2a5e0586</id>
<content type='text'>
Pull more misc uaccess and vfs updates from Al Viro:
 "The rest of the stuff from -next (more uaccess work) + assorted fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  score: traps: Add missing include file to fix build error
  fs/super.c: don't fool lockdep in freeze_super() and thaw_super() paths
  fs/super.c: fix race between freeze_super() and thaw_super()
  overlayfs: Fix setting IOP_XATTR flag
  iov_iter: kernel-doc import_iovec() and rw_copy_check_uvector()
  blackfin: no access_ok() for __copy_{to,from}_user()
  arm64: don't zero in __copy_from_user{,_inatomic}
  arm: don't zero in __copy_from_user_inatomic()/__copy_from_user()
  arc: don't leak bits of kernel stack into coredump
  alpha: get rid of tail-zeroing in __copy_user()
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull more misc uaccess and vfs updates from Al Viro:
 "The rest of the stuff from -next (more uaccess work) + assorted fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  score: traps: Add missing include file to fix build error
  fs/super.c: don't fool lockdep in freeze_super() and thaw_super() paths
  fs/super.c: fix race between freeze_super() and thaw_super()
  overlayfs: Fix setting IOP_XATTR flag
  iov_iter: kernel-doc import_iovec() and rw_copy_check_uvector()
  blackfin: no access_ok() for __copy_{to,from}_user()
  arm64: don't zero in __copy_from_user{,_inatomic}
  arm: don't zero in __copy_from_user_inatomic()/__copy_from_user()
  arc: don't leak bits of kernel stack into coredump
  alpha: get rid of tail-zeroing in __copy_user()
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'work.uaccess' into for-linus</title>
<updated>2016-10-15T00:42:44+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2016-10-15T00:42:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2692a71bbd40160165e89d5505c5c28144ec5a42'/>
<id>2692a71bbd40160165e89d5505c5c28144ec5a42</id>
<content type='text'>
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild</title>
<updated>2016-10-14T21:26:58+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-10-14T21:26:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=84d69848c97faab0c25aa2667b273404d2e2a64a'/>
<id>84d69848c97faab0c25aa2667b273404d2e2a64a</id>
<content type='text'>
Pull kbuild updates from Michal Marek:

 - EXPORT_SYMBOL for asm source by Al Viro.

   This does bring a regression, because genksyms no longer generates
   checksums for these symbols (CONFIG_MODVERSIONS). Nick Piggin is
   working on a patch to fix this.

   Plus, we are talking about functions like strcpy(), which rarely
   change prototypes.

 - Fixes for PPC fallout of the above by Stephen Rothwell and Nick
   Piggin

 - fixdep speedup by Alexey Dobriyan.

 - preparatory work by Nick Piggin to allow architectures to build with
   -ffunction-sections, -fdata-sections and --gc-sections

 - CONFIG_THIN_ARCHIVES support by Stephen Rothwell

 - fix for filenames with colons in the initramfs source by me.

* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (22 commits)
  initramfs: Escape colons in depfile
  ppc: there is no clear_pages to export
  powerpc/64: whitelist unresolved modversions CRCs
  kbuild: -ffunction-sections fix for archs with conflicting sections
  kbuild: add arch specific post-link Makefile
  kbuild: allow archs to select link dead code/data elimination
  kbuild: allow architectures to use thin archives instead of ld -r
  kbuild: Regenerate genksyms lexer
  kbuild: genksyms fix for typeof handling
  fixdep: faster CONFIG_ search
  ia64: move exports to definitions
  sparc32: debride memcpy.S a bit
  [sparc] unify 32bit and 64bit string.h
  sparc: move exports to definitions
  ppc: move exports to definitions
  arm: move exports to definitions
  s390: move exports to definitions
  m68k: move exports to definitions
  alpha: move exports to actual definitions
  x86: move exports to actual definitions
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull kbuild updates from Michal Marek:

 - EXPORT_SYMBOL for asm source by Al Viro.

   This does bring a regression, because genksyms no longer generates
   checksums for these symbols (CONFIG_MODVERSIONS). Nick Piggin is
   working on a patch to fix this.

   Plus, we are talking about functions like strcpy(), which rarely
   change prototypes.

 - Fixes for PPC fallout of the above by Stephen Rothwell and Nick
   Piggin

 - fixdep speedup by Alexey Dobriyan.

 - preparatory work by Nick Piggin to allow architectures to build with
   -ffunction-sections, -fdata-sections and --gc-sections

 - CONFIG_THIN_ARCHIVES support by Stephen Rothwell

 - fix for filenames with colons in the initramfs source by me.

* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (22 commits)
  initramfs: Escape colons in depfile
  ppc: there is no clear_pages to export
  powerpc/64: whitelist unresolved modversions CRCs
  kbuild: -ffunction-sections fix for archs with conflicting sections
  kbuild: add arch specific post-link Makefile
  kbuild: allow archs to select link dead code/data elimination
  kbuild: allow architectures to use thin archives instead of ld -r
  kbuild: Regenerate genksyms lexer
  kbuild: genksyms fix for typeof handling
  fixdep: faster CONFIG_ search
  ia64: move exports to definitions
  sparc32: debride memcpy.S a bit
  [sparc] unify 32bit and 64bit string.h
  sparc: move exports to definitions
  ppc: move exports to definitions
  arm: move exports to definitions
  s390: move exports to definitions
  m68k: move exports to definitions
  alpha: move exports to actual definitions
  x86: move exports to actual definitions
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2016-10-10T18:01:51+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-10-10T18:01:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=93c26d7dc02380fe11e57ff0d152368743762169'/>
<id>93c26d7dc02380fe11e57ff0d152368743762169</id>
<content type='text'>
Pull protection keys syscall interface from Thomas Gleixner:
 "This is the final step of Protection Keys support which adds the
  syscalls so user space can actually allocate keys and protect memory
  areas with them. Details and usage examples can be found in the
  documentation.

  The mm side of this has been acked by Mel"

* 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/pkeys: Update documentation
  x86/mm/pkeys: Do not skip PKRU register if debug registers are not used
  x86/pkeys: Fix pkeys build breakage for some non-x86 arches
  x86/pkeys: Add self-tests
  x86/pkeys: Allow configuration of init_pkru
  x86/pkeys: Default to a restrictive init PKRU
  pkeys: Add details of system call use to Documentation/
  generic syscalls: Wire up memory protection keys syscalls
  x86: Wire up protection keys system calls
  x86/pkeys: Allocation/free syscalls
  x86/pkeys: Make mprotect_key() mask off additional vm_flags
  mm: Implement new pkey_mprotect() system call
  x86/pkeys: Add fault handling for PF_PK page fault bit
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull protection keys syscall interface from Thomas Gleixner:
 "This is the final step of Protection Keys support which adds the
  syscalls so user space can actually allocate keys and protect memory
  areas with them. Details and usage examples can be found in the
  documentation.

  The mm side of this has been acked by Mel"

* 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/pkeys: Update documentation
  x86/mm/pkeys: Do not skip PKRU register if debug registers are not used
  x86/pkeys: Fix pkeys build breakage for some non-x86 arches
  x86/pkeys: Add self-tests
  x86/pkeys: Allow configuration of init_pkru
  x86/pkeys: Default to a restrictive init PKRU
  pkeys: Add details of system call use to Documentation/
  generic syscalls: Wire up memory protection keys syscalls
  x86: Wire up protection keys system calls
  x86/pkeys: Allocation/free syscalls
  x86/pkeys: Make mprotect_key() mask off additional vm_flags
  mm: Implement new pkey_mprotect() system call
  x86/pkeys: Add fault handling for PF_PK page fault bit
</pre>
</div>
</content>
</entry>
<entry>
<title>alpha: get rid of tail-zeroing in __copy_user()</title>
<updated>2016-09-15T23:51:54+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2016-09-10T20:21:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=085354f907969fb3ee33f236368f6e1dd4c74d62'/>
<id>085354f907969fb3ee33f236368f6e1dd4c74d62</id>
<content type='text'>
... and adjust copy_from_user() accordingly

Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
... and adjust copy_from_user() accordingly

Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>alpha: fix copy_from_user()</title>
<updated>2016-09-09T23:34:32+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2016-08-17T20:02:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2561d309dfd1555e781484af757ed0115035ddb3'/>
<id>2561d309dfd1555e781484af757ed0115035ddb3</id>
<content type='text'>
it should clear the destination even when access_ok() fails.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
it should clear the destination even when access_ok() fails.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/pkeys: Allocation/free syscalls</title>
<updated>2016-09-09T11:02:27+00:00</updated>
<author>
<name>Dave Hansen</name>
<email>dave.hansen@linux.intel.com</email>
</author>
<published>2016-07-29T16:30:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=e8c24d3a23a469f1f40d4de24d872ca7023ced0a'/>
<id>e8c24d3a23a469f1f40d4de24d872ca7023ced0a</id>
<content type='text'>
This patch adds two new system calls:

	int pkey_alloc(unsigned long flags, unsigned long init_access_rights)
	int pkey_free(int pkey);

These implement an "allocator" for the protection keys
themselves, which can be thought of as analogous to the allocator
that the kernel has for file descriptors.  The kernel tracks
which numbers are in use, and only allows operations on keys that
are valid.  A key which was not obtained by pkey_alloc() may not,
for instance, be passed to pkey_mprotect().

These system calls are also very important given the kernel's use
of pkeys to implement execute-only support.  These help ensure
that userspace can never assume that it has control of a key
unless it first asks the kernel.  The kernel does not promise to
preserve PKRU (right register) contents except for allocated
pkeys.

The 'init_access_rights' argument to pkey_alloc() specifies the
rights that will be established for the returned pkey.  For
instance:

	pkey = pkey_alloc(flags, PKEY_DENY_WRITE);

will allocate 'pkey', but also sets the bits in PKRU[1] such that
writing to 'pkey' is already denied.

The kernel does not prevent pkey_free() from successfully freeing
in-use pkeys (those still assigned to a memory range by
pkey_mprotect()).  It would be expensive to implement the checks
for this, so we instead say, "Just don't do it" since sane
software will never do it anyway.

Any piece of userspace calling pkey_alloc() needs to be prepared
for it to fail.  Why?  pkey_alloc() returns the same error code
(ENOSPC) when there are no pkeys and when pkeys are unsupported.
They can be unsupported for a whole host of reasons, so apps must
be prepared for this.  Also, libraries or LD_PRELOADs might steal
keys before an application gets access to them.

This allocation mechanism could be implemented in userspace.
Even if we did it in userspace, we would still need additional
user/kernel interfaces to tell userspace which keys are being
used by the kernel internally (such as for execute-only
mappings).  Having the kernel provide this facility completely
removes the need for these additional interfaces, or having an
implementation of this in userspace at all.

Note that we have to make changes to all of the architectures
that do not use mman-common.h because we use the new
PKEY_DENY_ACCESS/WRITE macros in arch-independent code.

1. PKRU is the Protection Key Rights User register.  It is a
   usermode-accessible register that controls whether writes
   and/or access to each individual pkey is allowed or denied.

Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Acked-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Cc: linux-arch@vger.kernel.org
Cc: Dave Hansen &lt;dave@sr71.net&gt;
Cc: arnd@arndb.de
Cc: linux-api@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: luto@kernel.org
Cc: akpm@linux-foundation.org
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/20160729163015.444FE75F@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch adds two new system calls:

	int pkey_alloc(unsigned long flags, unsigned long init_access_rights)
	int pkey_free(int pkey);

These implement an "allocator" for the protection keys
themselves, which can be thought of as analogous to the allocator
that the kernel has for file descriptors.  The kernel tracks
which numbers are in use, and only allows operations on keys that
are valid.  A key which was not obtained by pkey_alloc() may not,
for instance, be passed to pkey_mprotect().

These system calls are also very important given the kernel's use
of pkeys to implement execute-only support.  These help ensure
that userspace can never assume that it has control of a key
unless it first asks the kernel.  The kernel does not promise to
preserve PKRU (right register) contents except for allocated
pkeys.

The 'init_access_rights' argument to pkey_alloc() specifies the
rights that will be established for the returned pkey.  For
instance:

	pkey = pkey_alloc(flags, PKEY_DENY_WRITE);

will allocate 'pkey', but also sets the bits in PKRU[1] such that
writing to 'pkey' is already denied.

The kernel does not prevent pkey_free() from successfully freeing
in-use pkeys (those still assigned to a memory range by
pkey_mprotect()).  It would be expensive to implement the checks
for this, so we instead say, "Just don't do it" since sane
software will never do it anyway.

Any piece of userspace calling pkey_alloc() needs to be prepared
for it to fail.  Why?  pkey_alloc() returns the same error code
(ENOSPC) when there are no pkeys and when pkeys are unsupported.
They can be unsupported for a whole host of reasons, so apps must
be prepared for this.  Also, libraries or LD_PRELOADs might steal
keys before an application gets access to them.

This allocation mechanism could be implemented in userspace.
Even if we did it in userspace, we would still need additional
user/kernel interfaces to tell userspace which keys are being
used by the kernel internally (such as for execute-only
mappings).  Having the kernel provide this facility completely
removes the need for these additional interfaces, or having an
implementation of this in userspace at all.

Note that we have to make changes to all of the architectures
that do not use mman-common.h because we use the new
PKEY_DENY_ACCESS/WRITE macros in arch-independent code.

1. PKRU is the Protection Key Rights User register.  It is a
   usermode-accessible register that controls whether writes
   and/or access to each individual pkey is allowed or denied.

Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Acked-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Cc: linux-arch@vger.kernel.org
Cc: Dave Hansen &lt;dave@sr71.net&gt;
Cc: arnd@arndb.de
Cc: linux-api@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: luto@kernel.org
Cc: akpm@linux-foundation.org
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/20160729163015.444FE75F@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>alpha: move exports to actual definitions</title>
<updated>2016-08-08T03:47:18+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2016-01-11T14:51:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=00fc0e0dda6286407f3854cd71a125f519a5689c'/>
<id>00fc0e0dda6286407f3854cd71a125f519a5689c</id>
<content type='text'>
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
</feed>
