<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/kernel/events/core.c, branch v5.9-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'perf-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2020-08-15T17:34:24+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-08-15T17:34:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7f5faaaa5909bb0b26dcd309424da14bdf0c7e93'/>
<id>7f5faaaa5909bb0b26dcd309424da14bdf0c7e93</id>
<content type='text'>
Pull perf fixes from Ingo Molnar:
 "Misc fixes, an expansion of perf syscall access to CAP_PERFMON
  privileged tools, plus a RAPL HW-enablement for Intel SPR platforms"

* tag 'perf-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/rapl: Add support for Intel SPR platform
  perf/x86/rapl: Support multiple RAPL unit quirks
  perf/x86/rapl: Fix missing psys sysfs attributes
  hw_breakpoint: Remove unused __register_perf_hw_breakpoint() declaration
  kprobes: Remove show_registers() function prototype
  perf/core: Take over CAP_SYS_PTRACE creds to CAP_PERFMON capability
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull perf fixes from Ingo Molnar:
 "Misc fixes, an expansion of perf syscall access to CAP_PERFMON
  privileged tools, plus a RAPL HW-enablement for Intel SPR platforms"

* tag 'perf-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/rapl: Add support for Intel SPR platform
  perf/x86/rapl: Support multiple RAPL unit quirks
  perf/x86/rapl: Fix missing psys sysfs attributes
  hw_breakpoint: Remove unused __register_perf_hw_breakpoint() declaration
  kprobes: Remove show_registers() function prototype
  perf/core: Take over CAP_SYS_PTRACE creds to CAP_PERFMON capability
</pre>
</div>
</content>
</entry>
<entry>
<title>uaccess: add force_uaccess_{begin,end} helpers</title>
<updated>2020-08-12T17:57:59+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2020-08-12T01:33:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3d13f313ce4c34c524ccc37986fe77172f601ff3'/>
<id>3d13f313ce4c34c524ccc37986fe77172f601ff3</id>
<content type='text'>
Add helpers to wrap the get_fs/set_fs magic for undoing any damange done
by set_fs(KERNEL_DS).  There is no real functional benefit, but this
documents the intent of these calls better, and will allow stubbing the
functions out easily for kernels builds that do not allow address space
overrides in the future.

[hch@lst.de: drop two incorrect hunks, fix a commit log typo]
  Link: http://lkml.kernel.org/r/20200714105505.935079-6-hch@lst.de

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Acked-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Acked-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Acked-by: Greentime Hu &lt;green.hu@gmail.com&gt;
Acked-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Nick Hu &lt;nickhu@andestech.com&gt;
Cc: Vincent Chen &lt;deanbo422@gmail.com&gt;
Cc: Paul Walmsley &lt;paul.walmsley@sifive.com&gt;
Cc: Palmer Dabbelt &lt;palmer@dabbelt.com&gt;
Link: http://lkml.kernel.org/r/20200710135706.537715-6-hch@lst.de
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add helpers to wrap the get_fs/set_fs magic for undoing any damange done
by set_fs(KERNEL_DS).  There is no real functional benefit, but this
documents the intent of these calls better, and will allow stubbing the
functions out easily for kernels builds that do not allow address space
overrides in the future.

[hch@lst.de: drop two incorrect hunks, fix a commit log typo]
  Link: http://lkml.kernel.org/r/20200714105505.935079-6-hch@lst.de

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Acked-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Acked-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Acked-by: Greentime Hu &lt;green.hu@gmail.com&gt;
Acked-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Nick Hu &lt;nickhu@andestech.com&gt;
Cc: Vincent Chen &lt;deanbo422@gmail.com&gt;
Cc: Paul Walmsley &lt;paul.walmsley@sifive.com&gt;
Cc: Palmer Dabbelt &lt;palmer@dabbelt.com&gt;
Link: http://lkml.kernel.org/r/20200710135706.537715-6-hch@lst.de
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf/core: Take over CAP_SYS_PTRACE creds to CAP_PERFMON capability</title>
<updated>2020-08-06T13:03:20+00:00</updated>
<author>
<name>Alexey Budankov</name>
<email>alexey.budankov@linux.intel.com</email>
</author>
<published>2020-08-05T07:56:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=45fd22da97c6125d8d0d35bd1791e7c0c4175279'/>
<id>45fd22da97c6125d8d0d35bd1791e7c0c4175279</id>
<content type='text'>
Open access to per-process monitoring for CAP_PERFMON only
privileged processes [1]. Extend ptrace_may_access() check
in perf_events subsystem with perfmon_capable() to simplify
user experience and make monitoring more secure by reducing
attack surface.

[1] https://lore.kernel.org/lkml/7776fa40-6c65-2aa6-1322-eb3a01201000@linux.intel.com/

Signed-off-by: Alexey Budankov &lt;alexey.budankov@linux.intel.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Acked-by: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/6e8392ff-4732-0012-2949-e1587709f0f6@linux.intel.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Open access to per-process monitoring for CAP_PERFMON only
privileged processes [1]. Extend ptrace_may_access() check
in perf_events subsystem with perfmon_capable() to simplify
user experience and make monitoring more secure by reducing
attack surface.

[1] https://lore.kernel.org/lkml/7776fa40-6c65-2aa6-1322-eb3a01201000@linux.intel.com/

Signed-off-by: Alexey Budankov &lt;alexey.budankov@linux.intel.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Acked-by: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/6e8392ff-4732-0012-2949-e1587709f0f6@linux.intel.com
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next</title>
<updated>2020-08-06T03:13:21+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-08-06T03:13:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=47ec5303d73ea344e84f46660fff693c57641386'/>
<id>47ec5303d73ea344e84f46660fff693c57641386</id>
<content type='text'>
Pull networking updates from David Miller:

 1) Support 6Ghz band in ath11k driver, from Rajkumar Manoharan.

 2) Support UDP segmentation in code TSO code, from Eric Dumazet.

 3) Allow flashing different flash images in cxgb4 driver, from Vishal
    Kulkarni.

 4) Add drop frames counter and flow status to tc flower offloading,
    from Po Liu.

 5) Support n-tuple filters in cxgb4, from Vishal Kulkarni.

 6) Various new indirect call avoidance, from Eric Dumazet and Brian
    Vazquez.

 7) Fix BPF verifier failures on 32-bit pointer arithmetic, from
    Yonghong Song.

 8) Support querying and setting hardware address of a port function via
    devlink, use this in mlx5, from Parav Pandit.

 9) Support hw ipsec offload on bonding slaves, from Jarod Wilson.

10) Switch qca8k driver over to phylink, from Jonathan McDowell.

11) In bpftool, show list of processes holding BPF FD references to
    maps, programs, links, and btf objects. From Andrii Nakryiko.

12) Several conversions over to generic power management, from Vaibhav
    Gupta.

13) Add support for SO_KEEPALIVE et al. to bpf_setsockopt(), from Dmitry
    Yakunin.

14) Various https url conversions, from Alexander A. Klimov.

15) Timestamping and PHC support for mscc PHY driver, from Antoine
    Tenart.

16) Support bpf iterating over tcp and udp sockets, from Yonghong Song.

17) Support 5GBASE-T i40e NICs, from Aleksandr Loktionov.

18) Add kTLS RX HW offload support to mlx5e, from Tariq Toukan.

19) Fix the -&gt;ndo_start_xmit() return type to be netdev_tx_t in several
    drivers. From Luc Van Oostenryck.

20) XDP support for xen-netfront, from Denis Kirjanov.

21) Support receive buffer autotuning in MPTCP, from Florian Westphal.

22) Support EF100 chip in sfc driver, from Edward Cree.

23) Add XDP support to mvpp2 driver, from Matteo Croce.

24) Support MPTCP in sock_diag, from Paolo Abeni.

25) Commonize UDP tunnel offloading code by creating udp_tunnel_nic
    infrastructure, from Jakub Kicinski.

26) Several pci_ --&gt; dma_ API conversions, from Christophe JAILLET.

27) Add FLOW_ACTION_POLICE support to mlxsw, from Ido Schimmel.

28) Add SK_LOOKUP bpf program type, from Jakub Sitnicki.

29) Refactor a lot of networking socket option handling code in order to
    avoid set_fs() calls, from Christoph Hellwig.

30) Add rfc4884 support to icmp code, from Willem de Bruijn.

31) Support TBF offload in dpaa2-eth driver, from Ioana Ciornei.

32) Support XDP_REDIRECT in qede driver, from Alexander Lobakin.

33) Support PCI relaxed ordering in mlx5 driver, from Aya Levin.

34) Support TCP syncookies in MPTCP, from Flowian Westphal.

35) Fix several tricky cases of PMTU handling wrt. briding, from Stefano
    Brivio.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2056 commits)
  net: thunderx: initialize VF's mailbox mutex before first usage
  usb: hso: remove bogus check for EINPROGRESS
  usb: hso: no complaint about kmalloc failure
  hso: fix bailout in error case of probe
  ip_tunnel_core: Fix build for archs without _HAVE_ARCH_IPV6_CSUM
  selftests/net: relax cpu affinity requirement in msg_zerocopy test
  mptcp: be careful on subflow creation
  selftests: rtnetlink: make kci_test_encap() return sub-test result
  selftests: rtnetlink: correct the final return value for the test
  net: dsa: sja1105: use detected device id instead of DT one on mismatch
  tipc: set ub-&gt;ifindex for local ipv6 address
  ipv6: add ipv6_dev_find()
  net: openvswitch: silence suspicious RCU usage warning
  Revert "vxlan: fix tos value before xmit"
  ptp: only allow phase values lower than 1 period
  farsync: switch from 'pci_' to 'dma_' API
  wan: wanxl: switch from 'pci_' to 'dma_' API
  hv_netvsc: do not use VF device if link is down
  dpaa2-eth: Fix passing zero to 'PTR_ERR' warning
  net: macb: Properly handle phylink on at91sam9x
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull networking updates from David Miller:

 1) Support 6Ghz band in ath11k driver, from Rajkumar Manoharan.

 2) Support UDP segmentation in code TSO code, from Eric Dumazet.

 3) Allow flashing different flash images in cxgb4 driver, from Vishal
    Kulkarni.

 4) Add drop frames counter and flow status to tc flower offloading,
    from Po Liu.

 5) Support n-tuple filters in cxgb4, from Vishal Kulkarni.

 6) Various new indirect call avoidance, from Eric Dumazet and Brian
    Vazquez.

 7) Fix BPF verifier failures on 32-bit pointer arithmetic, from
    Yonghong Song.

 8) Support querying and setting hardware address of a port function via
    devlink, use this in mlx5, from Parav Pandit.

 9) Support hw ipsec offload on bonding slaves, from Jarod Wilson.

10) Switch qca8k driver over to phylink, from Jonathan McDowell.

11) In bpftool, show list of processes holding BPF FD references to
    maps, programs, links, and btf objects. From Andrii Nakryiko.

12) Several conversions over to generic power management, from Vaibhav
    Gupta.

13) Add support for SO_KEEPALIVE et al. to bpf_setsockopt(), from Dmitry
    Yakunin.

14) Various https url conversions, from Alexander A. Klimov.

15) Timestamping and PHC support for mscc PHY driver, from Antoine
    Tenart.

16) Support bpf iterating over tcp and udp sockets, from Yonghong Song.

17) Support 5GBASE-T i40e NICs, from Aleksandr Loktionov.

18) Add kTLS RX HW offload support to mlx5e, from Tariq Toukan.

19) Fix the -&gt;ndo_start_xmit() return type to be netdev_tx_t in several
    drivers. From Luc Van Oostenryck.

20) XDP support for xen-netfront, from Denis Kirjanov.

21) Support receive buffer autotuning in MPTCP, from Florian Westphal.

22) Support EF100 chip in sfc driver, from Edward Cree.

23) Add XDP support to mvpp2 driver, from Matteo Croce.

24) Support MPTCP in sock_diag, from Paolo Abeni.

25) Commonize UDP tunnel offloading code by creating udp_tunnel_nic
    infrastructure, from Jakub Kicinski.

26) Several pci_ --&gt; dma_ API conversions, from Christophe JAILLET.

27) Add FLOW_ACTION_POLICE support to mlxsw, from Ido Schimmel.

28) Add SK_LOOKUP bpf program type, from Jakub Sitnicki.

29) Refactor a lot of networking socket option handling code in order to
    avoid set_fs() calls, from Christoph Hellwig.

30) Add rfc4884 support to icmp code, from Willem de Bruijn.

31) Support TBF offload in dpaa2-eth driver, from Ioana Ciornei.

32) Support XDP_REDIRECT in qede driver, from Alexander Lobakin.

33) Support PCI relaxed ordering in mlx5 driver, from Aya Levin.

34) Support TCP syncookies in MPTCP, from Flowian Westphal.

35) Fix several tricky cases of PMTU handling wrt. briding, from Stefano
    Brivio.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2056 commits)
  net: thunderx: initialize VF's mailbox mutex before first usage
  usb: hso: remove bogus check for EINPROGRESS
  usb: hso: no complaint about kmalloc failure
  hso: fix bailout in error case of probe
  ip_tunnel_core: Fix build for archs without _HAVE_ARCH_IPV6_CSUM
  selftests/net: relax cpu affinity requirement in msg_zerocopy test
  mptcp: be careful on subflow creation
  selftests: rtnetlink: make kci_test_encap() return sub-test result
  selftests: rtnetlink: correct the final return value for the test
  net: dsa: sja1105: use detected device id instead of DT one on mismatch
  tipc: set ub-&gt;ifindex for local ipv6 address
  ipv6: add ipv6_dev_find()
  net: openvswitch: silence suspicious RCU usage warning
  Revert "vxlan: fix tos value before xmit"
  ptp: only allow phase values lower than 1 period
  farsync: switch from 'pci_' to 'dma_' API
  wan: wanxl: switch from 'pci_' to 'dma_' API
  hv_netvsc: do not use VF device if link is down
  dpaa2-eth: Fix passing zero to 'PTR_ERR' warning
  net: macb: Properly handle phylink on at91sam9x
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux</title>
<updated>2020-08-04T20:49:43+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-08-04T20:49:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=99ea1521a097db51f0f04f54cfbd3b0ed119d2f1'/>
<id>99ea1521a097db51f0f04f54cfbd3b0ed119d2f1</id>
<content type='text'>
Pull uninitialized_var() macro removal from Kees Cook:
 "This is long overdue, and has hidden too many bugs over the years. The
  series has several "by hand" fixes, and then a trivial treewide
  replacement.

   - Clean up non-trivial uses of uninitialized_var()

   - Update documentation and checkpatch for uninitialized_var() removal

   - Treewide removal of uninitialized_var()"

* tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  compiler: Remove uninitialized_var() macro
  treewide: Remove uninitialized_var() usage
  checkpatch: Remove awareness of uninitialized_var() macro
  mm/debug_vm_pgtable: Remove uninitialized_var() usage
  f2fs: Eliminate usage of uninitialized_var() macro
  media: sur40: Remove uninitialized_var() usage
  KVM: PPC: Book3S PR: Remove uninitialized_var() usage
  clk: spear: Remove uninitialized_var() usage
  clk: st: Remove uninitialized_var() usage
  spi: davinci: Remove uninitialized_var() usage
  ide: Remove uninitialized_var() usage
  rtlwifi: rtl8192cu: Remove uninitialized_var() usage
  b43: Remove uninitialized_var() usage
  drbd: Remove uninitialized_var() usage
  x86/mm/numa: Remove uninitialized_var() usage
  docs: deprecated.rst: Add uninitialized_var()
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull uninitialized_var() macro removal from Kees Cook:
 "This is long overdue, and has hidden too many bugs over the years. The
  series has several "by hand" fixes, and then a trivial treewide
  replacement.

   - Clean up non-trivial uses of uninitialized_var()

   - Update documentation and checkpatch for uninitialized_var() removal

   - Treewide removal of uninitialized_var()"

* tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  compiler: Remove uninitialized_var() macro
  treewide: Remove uninitialized_var() usage
  checkpatch: Remove awareness of uninitialized_var() macro
  mm/debug_vm_pgtable: Remove uninitialized_var() usage
  f2fs: Eliminate usage of uninitialized_var() macro
  media: sur40: Remove uninitialized_var() usage
  KVM: PPC: Book3S PR: Remove uninitialized_var() usage
  clk: spear: Remove uninitialized_var() usage
  clk: st: Remove uninitialized_var() usage
  spi: davinci: Remove uninitialized_var() usage
  ide: Remove uninitialized_var() usage
  rtlwifi: rtl8192cu: Remove uninitialized_var() usage
  b43: Remove uninitialized_var() usage
  drbd: Remove uninitialized_var() usage
  x86/mm/numa: Remove uninitialized_var() usage
  docs: deprecated.rst: Add uninitialized_var()
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Fail PERF_EVENT_IOC_SET_BPF when bpf_get_[stack|stackid] cannot work</title>
<updated>2020-07-26T03:16:34+00:00</updated>
<author>
<name>Song Liu</name>
<email>songliubraving@fb.com</email>
</author>
<published>2020-07-23T18:06:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5d99cb2c86775b4780c02a339a9578bf9471ead9'/>
<id>5d99cb2c86775b4780c02a339a9578bf9471ead9</id>
<content type='text'>
bpf_get_[stack|stackid] on perf_events with precise_ip uses callchain
attached to perf_sample_data. If this callchain is not presented, do not
allow attaching BPF program that calls bpf_get_[stack|stackid] to this
event.

In the error case, -EPROTO is returned so that libbpf can identify this
error and print proper hint message.

Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20200723180648.1429892-3-songliubraving@fb.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
bpf_get_[stack|stackid] on perf_events with precise_ip uses callchain
attached to perf_sample_data. If this callchain is not presented, do not
allow attaching BPF program that calls bpf_get_[stack|stackid] to this
event.

In the error case, -EPROTO is returned so that libbpf can identify this
error and print proper hint message.

Signed-off-by: Song Liu &lt;songliubraving@fb.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20200723180648.1429892-3-songliubraving@fb.com
</pre>
</div>
</content>
</entry>
<entry>
<title>treewide: Remove uninitialized_var() usage</title>
<updated>2020-07-16T19:35:15+00:00</updated>
<author>
<name>Kees Cook</name>
<email>keescook@chromium.org</email>
</author>
<published>2020-06-03T20:09:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3f649ab728cda8038259d8f14492fe400fbab911'/>
<id>3f649ab728cda8038259d8f14492fe400fbab911</id>
<content type='text'>
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky &lt;leonro@mellanox.com&gt; # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt; # IB
Acked-by: Kalle Valo &lt;kvalo@codeaurora.org&gt; # wireless drivers
Reviewed-by: Chao Yu &lt;yuchao0@huawei.com&gt; # erofs
Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky &lt;leonro@mellanox.com&gt; # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt; # IB
Acked-by: Kalle Valo &lt;kvalo@codeaurora.org&gt; # wireless drivers
Reviewed-by: Chao Yu &lt;yuchao0@huawei.com&gt; # erofs
Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf/x86: Remove task_ctx_size</title>
<updated>2020-07-08T09:38:55+00:00</updated>
<author>
<name>Kan Liang</name>
<email>kan.liang@linux.intel.com</email>
</author>
<published>2020-07-03T12:49:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5a09928d339f3cf0973991ddc3a2798825c84c99'/>
<id>5a09928d339f3cf0973991ddc3a2798825c84c99</id>
<content type='text'>
A new kmem_cache method has replaced the kzalloc() to allocate the PMU
specific data. The task_ctx_size is not required anymore.

Signed-off-by: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/1593780569-62993-19-git-send-email-kan.liang@linux.intel.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
A new kmem_cache method has replaced the kzalloc() to allocate the PMU
specific data. The task_ctx_size is not required anymore.

Signed-off-by: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/1593780569-62993-19-git-send-email-kan.liang@linux.intel.com
</pre>
</div>
</content>
</entry>
<entry>
<title>perf/core: Use kmem_cache to allocate the PMU specific data</title>
<updated>2020-07-08T09:38:55+00:00</updated>
<author>
<name>Kan Liang</name>
<email>kan.liang@linux.intel.com</email>
</author>
<published>2020-07-03T12:49:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=217c2a633ebb36f1cc6d249f4ef2e4a809d46818'/>
<id>217c2a633ebb36f1cc6d249f4ef2e4a809d46818</id>
<content type='text'>
Currently, the PMU specific data task_ctx_data is allocated by the
function kzalloc() in the perf generic code. When there is no specific
alignment requirement for the task_ctx_data, the method works well for
now. However, there will be a problem once a specific alignment
requirement is introduced in future features, e.g., the Architecture LBR
XSAVE feature requires 64-byte alignment. If the specific alignment
requirement is not fulfilled, the XSAVE family of instructions will fail
to save/restore the xstate to/from the task_ctx_data.

The function kzalloc() itself only guarantees a natural alignment. A
new method to allocate the task_ctx_data has to be introduced, which
has to meet the requirements as below:
- must be a generic method can be used by different architectures,
  because the allocation of the task_ctx_data is implemented in the
  perf generic code;
- must be an alignment-guarantee method (The alignment requirement is
  not changed after the boot);
- must be able to allocate/free a buffer (smaller than a page size)
  dynamically;
- should not cause extra CPU overhead or space overhead.

Several options were considered as below:
- One option is to allocate a larger buffer for task_ctx_data. E.g.,
    ptr = kmalloc(size + alignment, GFP_KERNEL);
    ptr &amp;= ~(alignment - 1);
  This option causes space overhead.
- Another option is to allocate the task_ctx_data in the PMU specific
  code. To do so, several function pointers have to be added. As a
  result, both the generic structure and the PMU specific structure
  will become bigger. Besides, extra function calls are added when
  allocating/freeing the buffer. This option will increase both the
  space overhead and CPU overhead.
- The third option is to use a kmem_cache to allocate a buffer for the
  task_ctx_data. The kmem_cache can be created with a specific alignment
  requirement by the PMU at boot time. A new pointer for kmem_cache has
  to be added in the generic struct pmu, which would be used to
  dynamically allocate a buffer for the task_ctx_data at run time.
  Although the new pointer is added to the struct pmu, the existing
  variable task_ctx_size is not required anymore. The size of the
  generic structure is kept the same.

The third option which meets all the aforementioned requirements is used
to replace kzalloc() for the PMU specific data allocation. A later patch
will remove the kzalloc() method and the related variables.

Signed-off-by: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/1593780569-62993-17-git-send-email-kan.liang@linux.intel.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently, the PMU specific data task_ctx_data is allocated by the
function kzalloc() in the perf generic code. When there is no specific
alignment requirement for the task_ctx_data, the method works well for
now. However, there will be a problem once a specific alignment
requirement is introduced in future features, e.g., the Architecture LBR
XSAVE feature requires 64-byte alignment. If the specific alignment
requirement is not fulfilled, the XSAVE family of instructions will fail
to save/restore the xstate to/from the task_ctx_data.

The function kzalloc() itself only guarantees a natural alignment. A
new method to allocate the task_ctx_data has to be introduced, which
has to meet the requirements as below:
- must be a generic method can be used by different architectures,
  because the allocation of the task_ctx_data is implemented in the
  perf generic code;
- must be an alignment-guarantee method (The alignment requirement is
  not changed after the boot);
- must be able to allocate/free a buffer (smaller than a page size)
  dynamically;
- should not cause extra CPU overhead or space overhead.

Several options were considered as below:
- One option is to allocate a larger buffer for task_ctx_data. E.g.,
    ptr = kmalloc(size + alignment, GFP_KERNEL);
    ptr &amp;= ~(alignment - 1);
  This option causes space overhead.
- Another option is to allocate the task_ctx_data in the PMU specific
  code. To do so, several function pointers have to be added. As a
  result, both the generic structure and the PMU specific structure
  will become bigger. Besides, extra function calls are added when
  allocating/freeing the buffer. This option will increase both the
  space overhead and CPU overhead.
- The third option is to use a kmem_cache to allocate a buffer for the
  task_ctx_data. The kmem_cache can be created with a specific alignment
  requirement by the PMU at boot time. A new pointer for kmem_cache has
  to be added in the generic struct pmu, which would be used to
  dynamically allocate a buffer for the task_ctx_data at run time.
  Although the new pointer is added to the struct pmu, the existing
  variable task_ctx_size is not required anymore. The size of the
  generic structure is kept the same.

The third option which meets all the aforementioned requirements is used
to replace kzalloc() for the PMU specific data allocation. A later patch
will remove the kzalloc() method and the related variables.

Signed-off-by: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/1593780569-62993-17-git-send-email-kan.liang@linux.intel.com
</pre>
</div>
</content>
</entry>
<entry>
<title>perf/core: Factor out functions to allocate/free the task_ctx_data</title>
<updated>2020-07-08T09:38:54+00:00</updated>
<author>
<name>Kan Liang</name>
<email>kan.liang@linux.intel.com</email>
</author>
<published>2020-07-03T12:49:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ff9ff926889dd8026b4ba55266a010c27f68604f'/>
<id>ff9ff926889dd8026b4ba55266a010c27f68604f</id>
<content type='text'>
The method to allocate/free the task_ctx_data is going to be changed in
the following patch. Currently, the task_ctx_data is allocated/freed in
several different places. To avoid repeatedly modifying the same codes
in several different places, alloc_task_ctx_data() and
free_task_ctx_data() are factored out to allocate/free the
task_ctx_data. The modification only needs to be applied once.

Signed-off-by: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/1593780569-62993-16-git-send-email-kan.liang@linux.intel.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The method to allocate/free the task_ctx_data is going to be changed in
the following patch. Currently, the task_ctx_data is allocated/freed in
several different places. To avoid repeatedly modifying the same codes
in several different places, alloc_task_ctx_data() and
free_task_ctx_data() are factored out to allocate/free the
task_ctx_data. The modification only needs to be applied once.

Signed-off-by: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/1593780569-62993-16-git-send-email-kan.liang@linux.intel.com
</pre>
</div>
</content>
</entry>
</feed>
