<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/sparc/include, branch v4.17</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>sparc64: Fix mistake in oradax license text</title>
<updated>2018-04-30T20:06:01+00:00</updated>
<author>
<name>Rob Gardner</name>
<email>rob.gardner@oracle.com</email>
</author>
<published>2018-04-20T18:48:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=d3c68d0b4183ddfa05577348a231dd117e6563df'/>
<id>d3c68d0b4183ddfa05577348a231dd117e6563df</id>
<content type='text'>
The license text in both oradax files mistakenly specifies "version 3" of
the GNU General Public License.  This is corrected to specify "version 2".

Signed-off-by: Rob Gardner &lt;rob.gardner@oracle.com&gt;
Signed-off-by: Jonathan Helman &lt;jonathan.helman@oracle.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The license text in both oradax files mistakenly specifies "version 3" of
the GNU General Public License.  This is corrected to specify "version 2".

Signed-off-by: Rob Gardner &lt;rob.gardner@oracle.com&gt;
Signed-off-by: Jonathan Helman &lt;jonathan.helman@oracle.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next</title>
<updated>2018-04-03T21:08:58+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-04-03T21:08:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=4608f064532c28c0ea3c03fe26a3a5909852811a'/>
<id>4608f064532c28c0ea3c03fe26a3a5909852811a</id>
<content type='text'>
Pull sparc updates from David Miller:

 1) Add support for ADI (Application Data Integrity) found in more
    recent sparc64 cpus. Essentially this is keyed based access to
    virtual memory, and if the key encoded in the virual address is
    wrong you get a trap.

    The mm changes were reviewed by Andrew Morton and others.

    Work by Khalid Aziz.

 2) Validate DAX completion index range properly, from Rob Gardner.

 3) Add proper Kconfig deps for DAX driver. From Guenter Roeck.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next:
  sparc64: Make atomic_xchg() an inline function rather than a macro.
  sparc64: Properly range check DAX completion index
  sparc: Make auxiliary vectors for ADI available on 32-bit as well
  sparc64: Oracle DAX driver depends on SPARC64
  sparc64: Update signal delivery to use new helper functions
  sparc64: Add support for ADI (Application Data Integrity)
  mm: Allow arch code to override copy_highpage()
  mm: Clear arch specific VM flags on protection change
  mm: Add address parameter to arch_validate_prot()
  sparc64: Add auxiliary vectors to report platform ADI properties
  sparc64: Add handler for "Memory Corruption Detected" trap
  sparc64: Add HV fault type handlers for ADI related faults
  sparc64: Add support for ADI register fields, ASIs and traps
  mm, swap: Add infrastructure for saving page metadata on swap
  signals, sparc: Add signal codes for ADI violations
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull sparc updates from David Miller:

 1) Add support for ADI (Application Data Integrity) found in more
    recent sparc64 cpus. Essentially this is keyed based access to
    virtual memory, and if the key encoded in the virual address is
    wrong you get a trap.

    The mm changes were reviewed by Andrew Morton and others.

    Work by Khalid Aziz.

 2) Validate DAX completion index range properly, from Rob Gardner.

 3) Add proper Kconfig deps for DAX driver. From Guenter Roeck.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next:
  sparc64: Make atomic_xchg() an inline function rather than a macro.
  sparc64: Properly range check DAX completion index
  sparc: Make auxiliary vectors for ADI available on 32-bit as well
  sparc64: Oracle DAX driver depends on SPARC64
  sparc64: Update signal delivery to use new helper functions
  sparc64: Add support for ADI (Application Data Integrity)
  mm: Allow arch code to override copy_highpage()
  mm: Clear arch specific VM flags on protection change
  mm: Add address parameter to arch_validate_prot()
  sparc64: Add auxiliary vectors to report platform ADI properties
  sparc64: Add handler for "Memory Corruption Detected" trap
  sparc64: Add HV fault type handlers for ADI related faults
  sparc64: Add support for ADI register fields, ASIs and traps
  mm, swap: Add infrastructure for saving page metadata on swap
  signals, sparc: Add signal codes for ADI violations
</pre>
</div>
</content>
</entry>
<entry>
<title>sparc64: Make atomic_xchg() an inline function rather than a macro.</title>
<updated>2018-04-03T15:24:35+00:00</updated>
<author>
<name>David S. Miller</name>
<email>davem@davemloft.net</email>
</author>
<published>2018-04-03T15:24:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=d13864b68e41c11e4231de90cf358658f6ecea45'/>
<id>d13864b68e41c11e4231de90cf358658f6ecea45</id>
<content type='text'>
This avoids a lot of -Wunused warnings such as:

====================
kernel/debug/debug_core.c: In function ‘kgdb_cpu_enter’:
./arch/sparc/include/asm/cmpxchg_64.h:55:22: warning: value computed is not used [-Wunused-value]
 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))

./arch/sparc/include/asm/atomic_64.h:86:30: note: in expansion of macro ‘xchg’
 #define atomic_xchg(v, new) (xchg(&amp;((v)-&gt;counter), new))
                              ^~~~
kernel/debug/debug_core.c:508:4: note: in expansion of macro ‘atomic_xchg’
    atomic_xchg(&amp;kgdb_active, cpu);
    ^~~~~~~~~~~
====================

Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This avoids a lot of -Wunused warnings such as:

====================
kernel/debug/debug_core.c: In function ‘kgdb_cpu_enter’:
./arch/sparc/include/asm/cmpxchg_64.h:55:22: warning: value computed is not used [-Wunused-value]
 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))

./arch/sparc/include/asm/atomic_64.h:86:30: note: in expansion of macro ‘xchg’
 #define atomic_xchg(v, new) (xchg(&amp;((v)-&gt;counter), new))
                              ^~~~
kernel/debug/debug_core.c:508:4: note: in expansion of macro ‘atomic_xchg’
    atomic_xchg(&amp;kgdb_active, cpu);
    ^~~~~~~~~~~
====================

Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'nds32-for-linus-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux</title>
<updated>2018-04-03T02:41:08+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-04-03T02:41:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c9297d284126b80c9cfd72c690e0da531c99fc48'/>
<id>c9297d284126b80c9cfd72c690e0da531c99fc48</id>
<content type='text'>
Pull nds32 architecture support from Greentime Hu:
 "This contains the core nds32 Linux port (including interrupt
  controller driver and timer driver), which has been through seven
  rounds of review on mailing list.

  It is able to boot to shell and passes most LTP-2017 testsuites in
  nds32 AE3XX platform:

    Total Tests: 1901
    Total Skipped Tests: 618
    Total Failures: 78"

Reviewed-by: Arnd Bergmann &lt;arnd@arndb.de&gt;

* tag 'nds32-for-linus-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux: (44 commits)
  nds32: To use the generic dump_stack()
  nds32: fix building failed if using elf toolchain.
  nios2: add ioremap_nocache declaration before include asm-generic/io.h.
  nds32: fix building failed if using older version gcc.
  dt-bindings: timer: Add andestech atcpit100 timer binding doc
  clocksource/drivers/atcpit100: VDSO support
  clocksource/drivers/atcpit100: Add andestech atcpit100 timer
  net: faraday add nds32 support.
  irqchip: Andestech Internal Vector Interrupt Controller driver
  dt-bindings: interrupt-controller: Andestech Internal Vector Interrupt Controller
  dt-bindings: nds32 SoC Bindings
  dt-bindings: nds32 L2 cache controller Bindings
  dt-bindings: nds32 CPU Bindings
  MAINTAINERS: Add nds32
  nds32: Build infrastructure
  nds32: defconfig
  nds32: Miscellaneous header files
  nds32: Device tree support
  nds32: Generic timers support
  nds32: Loadable modules
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull nds32 architecture support from Greentime Hu:
 "This contains the core nds32 Linux port (including interrupt
  controller driver and timer driver), which has been through seven
  rounds of review on mailing list.

  It is able to boot to shell and passes most LTP-2017 testsuites in
  nds32 AE3XX platform:

    Total Tests: 1901
    Total Skipped Tests: 618
    Total Failures: 78"

Reviewed-by: Arnd Bergmann &lt;arnd@arndb.de&gt;

* tag 'nds32-for-linus-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux: (44 commits)
  nds32: To use the generic dump_stack()
  nds32: fix building failed if using elf toolchain.
  nios2: add ioremap_nocache declaration before include asm-generic/io.h.
  nds32: fix building failed if using older version gcc.
  dt-bindings: timer: Add andestech atcpit100 timer binding doc
  clocksource/drivers/atcpit100: VDSO support
  clocksource/drivers/atcpit100: Add andestech atcpit100 timer
  net: faraday add nds32 support.
  irqchip: Andestech Internal Vector Interrupt Controller driver
  dt-bindings: interrupt-controller: Andestech Internal Vector Interrupt Controller
  dt-bindings: nds32 SoC Bindings
  dt-bindings: nds32 L2 cache controller Bindings
  dt-bindings: nds32 CPU Bindings
  MAINTAINERS: Add nds32
  nds32: Build infrastructure
  nds32: defconfig
  nds32: Miscellaneous header files
  nds32: Device tree support
  nds32: Generic timers support
  nds32: Loadable modules
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>sparc: Make auxiliary vectors for ADI available on 32-bit as well</title>
<updated>2018-03-20T15:14:31+00:00</updated>
<author>
<name>Khalid Aziz</name>
<email>khalid.aziz@oracle.com</email>
</author>
<published>2018-03-20T14:46:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=257a1aac7a9ae82db9c84a263a883c6f17789fea'/>
<id>257a1aac7a9ae82db9c84a263a883c6f17789fea</id>
<content type='text'>
Commit c6202ca764ac ("sparc64: Add auxiliary vectors to report
platform ADI properties") adds auxiliary vectors to report ADI
capabilities on sparc64 platform only. This needs to be uniform
across 64-bit and 32-bit. This patch makes the same vectors
available on 32-bit as well.

Signed-off-by: Khalid Aziz &lt;khalid.aziz@oracle.com&gt;
Cc: Khalid Aziz &lt;khalid@gonehiking.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit c6202ca764ac ("sparc64: Add auxiliary vectors to report
platform ADI properties") adds auxiliary vectors to report ADI
capabilities on sparc64 platform only. This needs to be uniform
across 64-bit and 32-bit. This patch makes the same vectors
available on 32-bit as well.

Signed-off-by: Khalid Aziz &lt;khalid.aziz@oracle.com&gt;
Cc: Khalid Aziz &lt;khalid@gonehiking.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sparc64: Add support for ADI (Application Data Integrity)</title>
<updated>2018-03-18T14:38:48+00:00</updated>
<author>
<name>Khalid Aziz</name>
<email>khalid.aziz@oracle.com</email>
</author>
<published>2018-02-23T22:46:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=74a04967482faa7144b93dae3b2e913870dd421c'/>
<id>74a04967482faa7144b93dae3b2e913870dd421c</id>
<content type='text'>
ADI is a new feature supported on SPARC M7 and newer processors to allow
hardware to catch rogue accesses to memory. ADI is supported for data
fetches only and not instruction fetches. An app can enable ADI on its
data pages, set version tags on them and use versioned addresses to
access the data pages. Upper bits of the address contain the version
tag. On M7 processors, upper four bits (bits 63-60) contain the version
tag. If a rogue app attempts to access ADI enabled data pages, its
access is blocked and processor generates an exception. Please see
Documentation/sparc/adi.txt for further details.

This patch extends mprotect to enable ADI (TSTATE.mcde), enable/disable
MCD (Memory Corruption Detection) on selected memory ranges, enable
TTE.mcd in PTEs, return ADI parameters to userspace and save/restore ADI
version tags on page swap out/in or migration. ADI is not enabled by
default for any task. A task must explicitly enable ADI on a memory
range and set version tag for ADI to be effective for the task.

Signed-off-by: Khalid Aziz &lt;khalid.aziz@oracle.com&gt;
Cc: Khalid Aziz &lt;khalid@gonehiking.org&gt;
Reviewed-by: Anthony Yznaga &lt;anthony.yznaga@oracle.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
ADI is a new feature supported on SPARC M7 and newer processors to allow
hardware to catch rogue accesses to memory. ADI is supported for data
fetches only and not instruction fetches. An app can enable ADI on its
data pages, set version tags on them and use versioned addresses to
access the data pages. Upper bits of the address contain the version
tag. On M7 processors, upper four bits (bits 63-60) contain the version
tag. If a rogue app attempts to access ADI enabled data pages, its
access is blocked and processor generates an exception. Please see
Documentation/sparc/adi.txt for further details.

This patch extends mprotect to enable ADI (TSTATE.mcde), enable/disable
MCD (Memory Corruption Detection) on selected memory ranges, enable
TTE.mcd in PTEs, return ADI parameters to userspace and save/restore ADI
version tags on page swap out/in or migration. ADI is not enabled by
default for any task. A task must explicitly enable ADI on a memory
range and set version tag for ADI to be effective for the task.

Signed-off-by: Khalid Aziz &lt;khalid.aziz@oracle.com&gt;
Cc: Khalid Aziz &lt;khalid@gonehiking.org&gt;
Reviewed-by: Anthony Yznaga &lt;anthony.yznaga@oracle.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sparc64: Add auxiliary vectors to report platform ADI properties</title>
<updated>2018-03-18T14:38:46+00:00</updated>
<author>
<name>Khalid Aziz</name>
<email>khalid.aziz@oracle.com</email>
</author>
<published>2018-02-21T17:15:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c6202ca764ac7b3728e29bca616567beb57fbac7'/>
<id>c6202ca764ac7b3728e29bca616567beb57fbac7</id>
<content type='text'>
ADI feature on M7 and newer processors has three important properties
relevant to userspace apps using ADI capabilities - (1) Size of block of
memory an ADI version tag applies to, (2) Number of uppermost bits in
virtual address used to encode ADI tag, and (3) The value M7 processor
will force the ADI tags to if it detects uncorrectable error in an ADI
tagged cacheline. Kernel can retrieve these properties for a platform
through machine description provided by the firmware. This patch adds
code to retrieve these properties and report them to userspace through
auxiliary vectors.

Signed-off-by: Khalid Aziz &lt;khalid.aziz@oracle.com&gt;
Cc: Khalid Aziz &lt;khalid@gonehiking.org&gt;
Reviewed-by: Anthony Yznaga &lt;anthony.yznaga@oracle.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
ADI feature on M7 and newer processors has three important properties
relevant to userspace apps using ADI capabilities - (1) Size of block of
memory an ADI version tag applies to, (2) Number of uppermost bits in
virtual address used to encode ADI tag, and (3) The value M7 processor
will force the ADI tags to if it detects uncorrectable error in an ADI
tagged cacheline. Kernel can retrieve these properties for a platform
through machine description provided by the firmware. This patch adds
code to retrieve these properties and report them to userspace through
auxiliary vectors.

Signed-off-by: Khalid Aziz &lt;khalid.aziz@oracle.com&gt;
Cc: Khalid Aziz &lt;khalid@gonehiking.org&gt;
Reviewed-by: Anthony Yznaga &lt;anthony.yznaga@oracle.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sparc64: Add support for ADI register fields, ASIs and traps</title>
<updated>2018-03-18T14:38:45+00:00</updated>
<author>
<name>Khalid Aziz</name>
<email>khalid.aziz@oracle.com</email>
</author>
<published>2018-02-21T17:15:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=750375003deae240967eed6b13529a4bfc8ca11e'/>
<id>750375003deae240967eed6b13529a4bfc8ca11e</id>
<content type='text'>
SPARC M7 processor adds new control register fields, ASIs and a new
trap to support the ADI (Application Data Integrity) feature. This
patch adds definitions for these register fields, ASIs and a handler
for the new precise memory corruption detected trap.

Signed-off-by: Khalid Aziz &lt;khalid.aziz@oracle.com&gt;
Cc: Khalid Aziz &lt;khalid@gonehiking.org&gt;
Reviewed-by: Anthony Yznaga &lt;anthony.yznaga@oracle.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
SPARC M7 processor adds new control register fields, ASIs and a new
trap to support the ADI (Application Data Integrity) feature. This
patch adds definitions for these register fields, ASIs and a handler
for the new precise memory corruption detected trap.

Signed-off-by: Khalid Aziz &lt;khalid.aziz@oracle.com&gt;
Cc: Khalid Aziz &lt;khalid@gonehiking.org&gt;
Reviewed-by: Anthony Yznaga &lt;anthony.yznaga@oracle.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>asm-generic/io.h: move ioremap_nocache/ioremap_uc/ioremap_wc/ioremap_wt out of ifndef CONFIG_MMU</title>
<updated>2018-02-22T02:44:30+00:00</updated>
<author>
<name>Greentime Hu</name>
<email>greentime@andestech.com</email>
</author>
<published>2017-11-22T10:57:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b3ada9d0ce8d286c8bbbb02fdbddec5036242b42'/>
<id>b3ada9d0ce8d286c8bbbb02fdbddec5036242b42</id>
<content type='text'>
It allows some architectures to use this generic macro instead of
defining theirs.

sparc: io: To use the define of ioremap_[nocache|wc|wb] in asm-generic/io.h
It will move the ioremap_nocache out of the CONFIG_MMU ifdef. This means that
in order to suppress re-definition errors we need to remove the #define
in arch/sparc/include/asm/io_32.h. Also, the change adds a prototype for
ioremap where size is size_t and offset is phys_addr_t so fix that as well.

Signed-off-by: Greentime Hu &lt;greentime@andestech.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
It allows some architectures to use this generic macro instead of
defining theirs.

sparc: io: To use the define of ioremap_[nocache|wc|wb] in asm-generic/io.h
It will move the ioremap_nocache out of the CONFIG_MMU ifdef. This means that
in order to suppress re-definition errors we need to remove the #define
in arch/sparc/include/asm/io_32.h. Also, the change adds a prototype for
ioremap where size is size_t and offset is phys_addr_t so fix that as well.

Signed-off-by: Greentime Hu &lt;greentime@andestech.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bug.h: work around GCC PR82365 in BUG()</title>
<updated>2018-02-21T23:35:43+00:00</updated>
<author>
<name>Arnd Bergmann</name>
<email>arnd@arndb.de</email>
</author>
<published>2018-02-21T22:45:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=173a3efd3edb2ef6ef07471397c5f542a360e9c1'/>
<id>173a3efd3edb2ef6ef07471397c5f542a360e9c1</id>
<content type='text'>
Looking at functions with large stack frames across all architectures
led me discovering that BUG() suffers from the same problem as
fortify_panic(), which I've added a workaround for already.

In short, variables that go out of scope by calling a noreturn function
or __builtin_unreachable() keep using stack space in functions
afterwards.

A workaround that was identified is to insert an empty assembler
statement just before calling the function that doesn't return.  I'm
adding a macro "barrier_before_unreachable()" to document this, and
insert calls to that in all instances of BUG() that currently suffer
from this problem.

The files that saw the largest change from this had these frame sizes
before, and much less with my patch:

  fs/ext4/inode.c:82:1: warning: the frame size of 1672 bytes is larger than 800 bytes [-Wframe-larger-than=]
  fs/ext4/namei.c:434:1: warning: the frame size of 904 bytes is larger than 800 bytes [-Wframe-larger-than=]
  fs/ext4/super.c:2279:1: warning: the frame size of 1160 bytes is larger than 800 bytes [-Wframe-larger-than=]
  fs/ext4/xattr.c:146:1: warning: the frame size of 1168 bytes is larger than 800 bytes [-Wframe-larger-than=]
  fs/f2fs/inode.c:152:1: warning: the frame size of 1424 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_core.c:1195:1: warning: the frame size of 1068 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_core.c:395:1: warning: the frame size of 1084 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_ftp.c:298:1: warning: the frame size of 928 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_ftp.c:418:1: warning: the frame size of 908 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_lblcr.c:718:1: warning: the frame size of 960 bytes is larger than 800 bytes [-Wframe-larger-than=]
  drivers/net/xen-netback/netback.c:1500:1: warning: the frame size of 1088 bytes is larger than 800 bytes [-Wframe-larger-than=]

In case of ARC and CRIS, it turns out that the BUG() implementation
actually does return (or at least the compiler thinks it does),
resulting in lots of warnings about uninitialized variable use and
leaving noreturn functions, such as:

  block/cfq-iosched.c: In function 'cfq_async_queue_prio':
  block/cfq-iosched.c:3804:1: error: control reaches end of non-void function [-Werror=return-type]
  include/linux/dmaengine.h: In function 'dma_maxpq':
  include/linux/dmaengine.h:1123:1: error: control reaches end of non-void function [-Werror=return-type]

This makes them call __builtin_trap() instead, which should normally
dump the stack and kill the current process, like some of the other
architectures already do.

I tried adding barrier_before_unreachable() to panic() and
fortify_panic() as well, but that had very little effect, so I'm not
submitting that patch.

Vineet said:

: For ARC, it is double win.
:
: 1. Fixes 3 -Wreturn-type warnings
:
: | ../net/core/ethtool.c:311:1: warning: control reaches end of non-void function
: [-Wreturn-type]
: | ../kernel/sched/core.c:3246:1: warning: control reaches end of non-void function
: [-Wreturn-type]
: | ../include/linux/sunrpc/svc_xprt.h:180:1: warning: control reaches end of
: non-void function [-Wreturn-type]
:
: 2.  bloat-o-meter reports code size improvements as gcc elides the
:    generated code for stack return.

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
Link: http://lkml.kernel.org/r/20171219114112.939391-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Acked-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;	[arch/arc]
Tested-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;	[arch/arc]
Cc: Mikael Starvik &lt;starvik@axis.com&gt;
Cc: Jesper Nilsson &lt;jesper.nilsson@axis.com&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Christopher Li &lt;sparse@chrisli.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: "Steven Rostedt (VMware)" &lt;rostedt@goodmis.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Looking at functions with large stack frames across all architectures
led me discovering that BUG() suffers from the same problem as
fortify_panic(), which I've added a workaround for already.

In short, variables that go out of scope by calling a noreturn function
or __builtin_unreachable() keep using stack space in functions
afterwards.

A workaround that was identified is to insert an empty assembler
statement just before calling the function that doesn't return.  I'm
adding a macro "barrier_before_unreachable()" to document this, and
insert calls to that in all instances of BUG() that currently suffer
from this problem.

The files that saw the largest change from this had these frame sizes
before, and much less with my patch:

  fs/ext4/inode.c:82:1: warning: the frame size of 1672 bytes is larger than 800 bytes [-Wframe-larger-than=]
  fs/ext4/namei.c:434:1: warning: the frame size of 904 bytes is larger than 800 bytes [-Wframe-larger-than=]
  fs/ext4/super.c:2279:1: warning: the frame size of 1160 bytes is larger than 800 bytes [-Wframe-larger-than=]
  fs/ext4/xattr.c:146:1: warning: the frame size of 1168 bytes is larger than 800 bytes [-Wframe-larger-than=]
  fs/f2fs/inode.c:152:1: warning: the frame size of 1424 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_core.c:1195:1: warning: the frame size of 1068 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_core.c:395:1: warning: the frame size of 1084 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_ftp.c:298:1: warning: the frame size of 928 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_ftp.c:418:1: warning: the frame size of 908 bytes is larger than 800 bytes [-Wframe-larger-than=]
  net/netfilter/ipvs/ip_vs_lblcr.c:718:1: warning: the frame size of 960 bytes is larger than 800 bytes [-Wframe-larger-than=]
  drivers/net/xen-netback/netback.c:1500:1: warning: the frame size of 1088 bytes is larger than 800 bytes [-Wframe-larger-than=]

In case of ARC and CRIS, it turns out that the BUG() implementation
actually does return (or at least the compiler thinks it does),
resulting in lots of warnings about uninitialized variable use and
leaving noreturn functions, such as:

  block/cfq-iosched.c: In function 'cfq_async_queue_prio':
  block/cfq-iosched.c:3804:1: error: control reaches end of non-void function [-Werror=return-type]
  include/linux/dmaengine.h: In function 'dma_maxpq':
  include/linux/dmaengine.h:1123:1: error: control reaches end of non-void function [-Werror=return-type]

This makes them call __builtin_trap() instead, which should normally
dump the stack and kill the current process, like some of the other
architectures already do.

I tried adding barrier_before_unreachable() to panic() and
fortify_panic() as well, but that had very little effect, so I'm not
submitting that patch.

Vineet said:

: For ARC, it is double win.
:
: 1. Fixes 3 -Wreturn-type warnings
:
: | ../net/core/ethtool.c:311:1: warning: control reaches end of non-void function
: [-Wreturn-type]
: | ../kernel/sched/core.c:3246:1: warning: control reaches end of non-void function
: [-Wreturn-type]
: | ../include/linux/sunrpc/svc_xprt.h:180:1: warning: control reaches end of
: non-void function [-Wreturn-type]
:
: 2.  bloat-o-meter reports code size improvements as gcc elides the
:    generated code for stack return.

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
Link: http://lkml.kernel.org/r/20171219114112.939391-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Acked-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;	[arch/arc]
Tested-by: Vineet Gupta &lt;vgupta@synopsys.com&gt;	[arch/arc]
Cc: Mikael Starvik &lt;starvik@axis.com&gt;
Cc: Jesper Nilsson &lt;jesper.nilsson@axis.com&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Christopher Li &lt;sparse@chrisli.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Cc: Will Deacon &lt;will.deacon@arm.com&gt;
Cc: "Steven Rostedt (VMware)" &lt;rostedt@goodmis.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
