<feed xmlns='http://www.w3.org/2005/Atom'>
<title>pm24.git/tools/include/uapi, branch v5.13-rc2</title>
<subtitle>Unnamed repository; edit this file 'description' to name the repository.
</subtitle>
<id>https://git.kobert.dev/pm24.git/atom?h=v5.13-rc2</id>
<link rel='self' href='https://git.kobert.dev/pm24.git/atom?h=v5.13-rc2'/>
<link rel='alternate' type='text/html' href='https://git.kobert.dev/pm24.git/'/>
<updated>2021-05-10T12:01:01Z</updated>
<entry>
<title>tools headers UAPI: Sync perf_event.h with the kernel sources</title>
<updated>2021-05-10T12:01:01Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2021-05-09T13:29:10Z</published>
<link rel='alternate' type='text/html' href='https://git.kobert.dev/pm24.git/commit/?id=71d7924b3e8acaca6a3b0fc3261170031ada3b70'/>
<id>urn:sha1:71d7924b3e8acaca6a3b0fc3261170031ada3b70</id>
<content type='text'>
To pick up the changes in:

  2b26f0aa004995f4 ("perf: Support only inheriting events if cloned with CLONE_THREAD")
  2e498d0a74e5b88a ("perf: Add support for event removal on exec")
  547b60988e631f74 ("perf: aux: Add flags for the buffer format")
  55bcf6ef314ae8ba ("perf: Extend PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE")
  7dde51767ca5339e ("perf: aux: Add CoreSight PMU buffer formats")
  97ba62b278674293 ("perf: Add support for SIGTRAP on perf events")
  d0d1dd628527c77d ("perf core: Add PERF_COUNT_SW_CGROUP_SWITCHES event")

Also change the expected sizeof(struct perf_event_attr) from 120 to 128 due to
fields being added for the SIGTRAP changes.

Addressing this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/perf_event.h' differs from latest version at 'include/uapi/linux/perf_event.h'
  diff -u tools/include/uapi/linux/perf_event.h include/uapi/linux/perf_event.h

Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Marco Elver &lt;elver@google.com&gt;
Cc: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools headers UAPI: Sync linux/prctl.h with the kernel sources</title>
<updated>2021-05-10T12:01:00Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2021-05-09T13:06:40Z</published>
<link rel='alternate' type='text/html' href='https://git.kobert.dev/pm24.git/commit/?id=5a80ee4219a52194f0e815bbceec40eb32c523ec'/>
<id>urn:sha1:5a80ee4219a52194f0e815bbceec40eb32c523ec</id>
<content type='text'>
To pick a new prctl introduced in:

  201698626fbca1cf ("arm64: Introduce prctl(PR_PAC_{SET,GET}_ENABLED_KEYS)")

That results in

  $ grep prctl tools/perf/trace/beauty/*.sh
  tools/perf/trace/beauty/prctl_option.sh:printf "static const char *prctl_options[] = {\n"
  tools/perf/trace/beauty/prctl_option.sh:egrep $regex ${header_dir}/prctl.h | grep -v PR_SET_PTRACER | \
  tools/perf/trace/beauty/prctl_option.sh:printf "static const char *prctl_set_mm_options[] = {\n"
  tools/perf/trace/beauty/prctl_option.sh:egrep $regex ${header_dir}/prctl.h | \
  tools/perf/trace/beauty/x86_arch_prctl.sh:prctl_arch_header=${x86_header_dir}/prctl.h
  tools/perf/trace/beauty/x86_arch_prctl.sh:	printf "#define x86_arch_prctl_codes_%d_offset %s\n" $idx $first_entry
  tools/perf/trace/beauty/x86_arch_prctl.sh:	printf "static const char *x86_arch_prctl_codes_%d[] = {\n" $idx
  tools/perf/trace/beauty/x86_arch_prctl.sh:	egrep -q $regex ${prctl_arch_header} &amp;&amp; \
  tools/perf/trace/beauty/x86_arch_prctl.sh:	(egrep $regex ${prctl_arch_header} | \
  $ tools/perf/trace/beauty/prctl_option.sh &gt; before
  $ cp include/uapi/linux/prctl.h tools/include/uapi/linux/prctl.h
  $ tools/perf/trace/beauty/prctl_option.sh &gt; after
  $ diff -u before after
  --- before	2021-05-09 10:06:10.064559675 -0300
  +++ after	2021-05-09 10:06:21.319791396 -0300
  @@ -54,6 +54,8 @@
   	[57] = "SET_IO_FLUSHER",
   	[58] = "GET_IO_FLUSHER",
   	[59] = "SET_SYSCALL_USER_DISPATCH",
  +	[60] = "PAC_SET_ENABLED_KEYS",
  +	[61] = "PAC_GET_ENABLED_KEYS",
   };
   static const char *prctl_set_mm_options[] = {
   	[1] = "START_CODE",
  $

Now users can do:

  # perf trace -e syscalls:sys_enter_prctl --filter "option==PAC_GET_ENABLED_KEYS"
^C#
  # trace -v -e syscalls:sys_enter_prctl --filter "option==PAC_GET_ENABLED_KEYS"
  New filter for syscalls:sys_enter_prctl: (option==0x3d) &amp;&amp; (common_pid != 5519 &amp;&amp; common_pid != 3404)
^C#

And also when prctl appears in a session, its options will be
translated to the string.

Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Peter Collingbourne &lt;pcc@google.com&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools headers UAPI: Sync files changed by landlock, quotactl_path and mount_settattr new syscalls</title>
<updated>2021-05-10T12:01:00Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2021-05-09T12:55:30Z</published>
<link rel='alternate' type='text/html' href='https://git.kobert.dev/pm24.git/commit/?id=f8bcb061ea013a9b39a071b9dd9f6ea0aa2caf72'/>
<id>urn:sha1:f8bcb061ea013a9b39a071b9dd9f6ea0aa2caf72</id>
<content type='text'>
To pick the changes in these csets:

  a49f4f81cb48925e ("arch: Wire up Landlock syscalls")
  2a1867219c7b27f9 ("fs: add mount_setattr()")
  fa8b90070a80bb1a ("quota: wire up quotactl_path")

That silences these perf build warnings and add support for those new
syscalls in tools such as 'perf trace'.

For instance, this is now possible:

  # ~acme/bin/perf trace -v -e landlock*
  event qualifier tracepoint filter: (common_pid != 129365 &amp;&amp; common_pid != 3502) &amp;&amp; (id == 444 || id == 445 || id == 446)
  ^C#

That is tha filter expression attached to the raw_syscalls:sys_{enter,exit}
tracepoints.

  $ grep landlock tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
  444	common	landlock_create_ruleset	sys_landlock_create_ruleset
  445	common	landlock_add_rule	sys_landlock_add_rule
  446	common	landlock_restrict_self	sys_landlock_restrict_self
  $

This addresses these perf build warnings:

  Warning: Kernel ABI header at 'tools/include/uapi/asm-generic/unistd.h' differs from latest version at 'include/uapi/asm-generic/unistd.h'
  diff -u tools/include/uapi/asm-generic/unistd.h include/uapi/asm-generic/unistd.h
  Warning: Kernel ABI header at 'tools/perf/arch/x86/entry/syscalls/syscall_64.tbl' differs from latest version at 'arch/x86/entry/syscalls/syscall_64.tbl'
  diff -u tools/perf/arch/x86/entry/syscalls/syscall_64.tbl arch/x86/entry/syscalls/syscall_64.tbl
  Warning: Kernel ABI header at 'tools/perf/arch/powerpc/entry/syscalls/syscall.tbl' differs from latest version at 'arch/powerpc/kernel/syscalls/syscall.tbl'
  diff -u tools/perf/arch/powerpc/entry/syscalls/syscall.tbl arch/powerpc/kernel/syscalls/syscall.tbl
  Warning: Kernel ABI header at 'tools/perf/arch/s390/entry/syscalls/syscall.tbl' differs from latest version at 'arch/s390/kernel/syscalls/syscall.tbl'
  diff -u tools/perf/arch/s390/entry/syscalls/syscall.tbl arch/s390/kernel/syscalls/syscall.tbl
  Warning: Kernel ABI header at 'tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl' differs from latest version at 'arch/mips/kernel/syscalls/syscall_n64.tbl'
  diff -u tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl arch/mips/kernel/syscalls/syscall_n64.tbl

Cc: Christian Brauner &lt;christian.brauner@ubuntu.com&gt;
Cc: James Morris &lt;jamorris@linux.microsoft.com&gt;
Cc: Jan Kara &lt;jack@suse.cz&gt;
Cc: Mickaël Salaün &lt;mic@linux.microsoft.com&gt;
Cc: Sascha Hauer &lt;s.hauer@pengutronix.de&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools headers UAPI: Sync linux/kvm.h with the kernel sources</title>
<updated>2021-05-10T12:01:00Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2021-05-09T12:39:02Z</published>
<link rel='alternate' type='text/html' href='https://git.kobert.dev/pm24.git/commit/?id=0d943d5fde6070c2661a99618ea95b99655589ad'/>
<id>urn:sha1:0d943d5fde6070c2661a99618ea95b99655589ad</id>
<content type='text'>
To pick the changes in:

  15fb7de1a7f5af0d ("KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command")
  3bf725699bf62494 ("KVM: arm64: Add support for the KVM PTP service")
  4cfdd47d6d95aca4 ("KVM: SVM: Add KVM_SEV SEND_START command")
  54526d1fd59338fd ("KVM: x86: Support KVM VMs sharing SEV context")
  5569e2e7a650dfff ("KVM: SVM: Add support for KVM_SEV_SEND_CANCEL command")
  8b13c36493d8cb56 ("KVM: introduce KVM_CAP_SET_GUEST_DEBUG2")
  af43cbbf954b50ca ("KVM: SVM: Add support for KVM_SEV_RECEIVE_START command")
  d3d1af85e2c75bb5 ("KVM: SVM: Add KVM_SEND_UPDATE_DATA command")
  fe7e948837f312d8 ("KVM: x86: Add capability to grant VM access to privileged SGX attribute")

That don't cause any change in tooling as it doesn't introduce any new
ioctl.

  $ grep kvm tools/perf/trace/beauty/*.sh
  tools/perf/trace/beauty/kvm_ioctl.sh:printf "static const char *kvm_ioctl_cmds[] = {\n"
  tools/perf/trace/beauty/kvm_ioctl.sh:egrep $regex ${header_dir}/kvm.h	| \
  $
  $ tools/perf/trace/beauty/kvm_ioctl.sh &gt; before
  $ cp include/uapi/linux/kvm.h tools/include/uapi/linux/kvm.h
  $ tools/perf/trace/beauty/kvm_ioctl.sh &gt; after
  $ diff -u before after
  $

This silences this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/kvm.h' differs from latest version at 'include/uapi/linux/kvm.h'
  diff -u tools/include/uapi/linux/kvm.h include/uapi/linux/kvm.h

Cc: Brijesh Singh &lt;brijesh.singh@amd.com&gt;
Cc: Jianyong Wu &lt;jianyong.wu@arm.com&gt;
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: Nathan Tempelman &lt;natet@google.com&gt;
Cc: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Cc: Sean Christopherson &lt;seanjc@google.com&gt;
Cc: Steve Rutherford &lt;srutherford@google.com&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools headers UAPI: Sync drm/i915_drm.h with the kernel sources</title>
<updated>2021-05-10T12:00:59Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2021-05-03T14:51:17Z</published>
<link rel='alternate' type='text/html' href='https://git.kobert.dev/pm24.git/commit/?id=0fdee797d60d71e5a6fd59aa573d84a858e715dd'/>
<id>urn:sha1:0fdee797d60d71e5a6fd59aa573d84a858e715dd</id>
<content type='text'>
To pick the changes in:

  b5b6f6a610127b17 ("drm/i915/gem: Drop legacy execbuffer support (v2)")

That don't result in any change in tooling as this is just adding a
comment.

Only silences this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/drm/i915_drm.h' differs from latest version at 'include/uapi/drm/i915_drm.h'
  diff -u tools/include/uapi/drm/i915_drm.h include/uapi/drm/i915_drm.h

Cc: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Cc: Jason Ekstrand &lt;jason@jlekstrand.net&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools headers UAPI: Update tools's copy of drm.h headers</title>
<updated>2021-05-10T12:00:59Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2021-05-03T14:48:26Z</published>
<link rel='alternate' type='text/html' href='https://git.kobert.dev/pm24.git/commit/?id=a3bc4ffeedf4693262fe7c6d133dcfcacd3d18c2'/>
<id>urn:sha1:a3bc4ffeedf4693262fe7c6d133dcfcacd3d18c2</id>
<content type='text'>
Picking the changes from:

  b603e810f740e76b ("drm/uapi: document kernel capabilities")

Doesn't result in any tooling changes:

  $ tools/perf/trace/beauty/drm_ioctl.sh  &gt; before
  $ cp include/uapi/drm/drm.h tools/include/uapi/drm/drm.h
  $ tools/perf/trace/beauty/drm_ioctl.sh  &gt; after
  $ diff -u before after

Silencing these perf build warnings:

  Warning: Kernel ABI header at 'tools/include/uapi/drm/drm.h' differs from latest version at 'include/uapi/drm/drm.h'
  diff -u tools/include/uapi/drm/drm.h include/uapi/drm/drm.h

Cc: Simon Ser &lt;contact@emersion.fr&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>Merge tag 'perf-tools-for-v5.13-2021-04-29' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux</title>
<updated>2021-05-01T19:22:38Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-05-01T19:22:38Z</published>
<link rel='alternate' type='text/html' href='https://git.kobert.dev/pm24.git/commit/?id=10a3efd0fee5e881b1866cf45950808575cb0f24'/>
<id>urn:sha1:10a3efd0fee5e881b1866cf45950808575cb0f24</id>
<content type='text'>
Pull perf tool updates from Arnaldo Carvalho de Melo:
 "perf stat:

   - Add support for hybrid PMUs to support systems such as Intel
     Alderlake and its BIG/little core/atom cpus.

   - Introduce 'bperf' to share hardware PMCs with BPF.

   - New --iostat option to collect and present IO stats on Intel
     hardware.

     This functionality is based on recently introduced sysfs attributes
     for Intel® Xeon® Scalable processor family (code name Skylake-SP)
     in commit bb42b3d39781 ("perf/x86/intel/uncore: Expose an Uncore
     unit to IIO PMON mapping")

     It is intended to provide four I/O performance metrics in MB per
     each PCIe root port:

       - Inbound Read: I/O devices below root port read from the host memory
       - Inbound Write: I/O devices below root port write to the host memory
       - Outbound Read: CPU reads from I/O devices below root port
       - Outbound Write: CPU writes to I/O devices below root port

   - Align CSV output for summary.

   - Clarify --null use cases: Assess raw overhead of 'perf stat' or
     measure just wall clock time.

   - Improve readability of shadow stats.

  perf record:

   - Change the COMM when starting tha workload so that --exclude-perf
     doesn't seem to be not honoured.

   - Improve 'Workload failed' message printing events + what was
     exec'ed.

   - Fix cross-arch support for TIME_CONV.

  perf report:

   - Add option to disable raw event ordering.

   - Dump the contents of PERF_RECORD_TIME_CONV in 'perf report -D'.

   - Improvements to --stat output, that shows information about
     PERF_RECORD_ events.

   - Preserve identifier id in OCaml demangler.

  perf annotate:

   - Show full source location with 'l' hotkey in the 'perf annotate'
     TUI.

   - Add line number like in TUI and source location at EOL to the 'perf
     annotate' --stdio mode.

   - Add --demangle and --demangle-kernel to 'perf annotate'.

   - Allow configuring annotate.demangle{,_kernel} in 'perf config'.

   - Fix sample events lost in stdio mode.

  perf data:

   - Allow converting a perf.data file to JSON.

  libperf:

   - Add support for user space counter access.

   - Update topdown documentation to permit rdpmc calls.

  perf test:

   - Add 'perf test' for 'perf stat' CSV output.

   - Add 'perf test' entries to test the hybrid PMU support.

   - Cleanup 'perf test daemon' if its 'perf test' is interrupted.

   - Handle metric reuse in pmu-events parsing 'perf test' entry.

   - Add test for PE executable support.

   - Add timeout for wait for daemon start in its 'perf test' entries.

  Build:

   - Enable libtraceevent dynamic linking.

   - Improve feature detection output.

   - Fix caching of feature checks caching.

   - First round of updates for tools copies of kernel headers.

   - Enable warnings when compiling BPF programs.

  Vendor specific events:

   - Intel:
      - Add missing skylake &amp; icelake model numbers.

   - arm64:
      - Add Hisi hip08 L1, L2 and L3 metrics.
      - Add Fujitsu A64FX PMU events.

   - PowerPC:
      - Initial JSON/events list for power10 platform.
      - Remove unsupported power9 metrics.

   - AMD:
      - Add Zen3 events.
      - Fix broken L2 Cache Hits from L2 HWPF metric.
      - Use lowercases for all the eventcodes and umasks.

  Hardware tracing:

   - arm64:
      - Update CoreSight ETM metadata format.
      - Fix bitmap for CS-ETM option.
      - Support PID tracing in config.
      - Detect pid in VMID for kernel running at EL2.

  Arch specific updates:

   - MIPS:
      - Support MIPS unwinding and dwarf-regs.
      - Generate mips syscalls_n64.c syscall table.

   - PowerPC:
      - Add support for PERF_SAMPLE_WEIGH_STRUCT on PowerPC.
      - Support pipeline stage cycles for powerpc.

  libbeauty:

   - Fix fsconfig generator"

* tag 'perf-tools-for-v5.13-2021-04-29' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (132 commits)
  perf build: Defer printing detected features to the end of all feature checks
  tools build: Allow deferring printing the results of feature detection
  perf build: Regenerate the FEATURE_DUMP file after extra feature checks
  perf session: Dump PERF_RECORD_TIME_CONV event
  perf session: Add swap operation for event TIME_CONV
  perf jit: Let convert_timestamp() to be backwards-compatible
  perf tools: Change fields type in perf_record_time_conv
  perf tools: Enable libtraceevent dynamic linking
  perf Documentation: Document intel-hybrid support
  perf tests: Skip 'perf stat metrics (shadow stat) test' for hybrid
  perf tests: Support 'Convert perf time to TSC' test for hybrid
  perf tests: Support 'Session topology' test for hybrid
  perf tests: Support 'Parse and process metrics' test for hybrid
  perf tests: Support 'Track with sched_switch' test for hybrid
  perf tests: Skip 'Setup struct perf_event_attr' test for hybrid
  perf tests: Add hybrid cases for 'Roundtrip evsel-&gt;name' test
  perf tests: Add hybrid cases for 'Parse event definition strings' test
  perf record: Uniquify hybrid event name
  perf stat: Warn group events from different hybrid PMU
  perf stat: Filter out unmatched aggregation for hybrid event
  ...
</content>
</entry>
<entry>
<title>tools headers uapi: Update tools's copy of linux/perf_event.h</title>
<updated>2021-04-29T13:30:59Z</updated>
<author>
<name>Jin Yao</name>
<email>yao.jin@linux.intel.com</email>
</author>
<published>2021-04-27T07:01:14Z</published>
<link rel='alternate' type='text/html' href='https://git.kobert.dev/pm24.git/commit/?id=412736119116d0161688e9061485fbc3e25f78d5'/>
<id>urn:sha1:412736119116d0161688e9061485fbc3e25f78d5</id>
<content type='text'>
To get the changes in:

Liang Kan's patch

  55bcf6ef314ae8ba ("perf: Extend PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE")

Kan's patch is in the tip/perf/core branch.

So the next perf tool patches need this interface for hybrid support.

Signed-off-by: Jin Yao &lt;yao.jin@linux.intel.com&gt;
Reviewed-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Kan Liang &lt;kan.liang@intel.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20210427070139.25256-2-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next</title>
<updated>2021-04-26T01:02:32Z</updated>
<author>
<name>David S. Miller</name>
<email>davem@davemloft.net</email>
</author>
<published>2021-04-26T01:02:32Z</published>
<link rel='alternate' type='text/html' href='https://git.kobert.dev/pm24.git/commit/?id=5f6c2f536de648ac31564d8c413337ff4f7af93a'/>
<id>urn:sha1:5f6c2f536de648ac31564d8c413337ff4f7af93a</id>
<content type='text'>
Alexei Starovoitov says:

====================
pull-request: bpf-next 2021-04-23

The following pull-request contains BPF updates for your *net-next* tree.

We've added 69 non-merge commits during the last 22 day(s) which contain
a total of 69 files changed, 3141 insertions(+), 866 deletions(-).

The main changes are:

1) Add BPF static linker support for extern resolution of global, from Andrii.

2) Refine retval for bpf_get_task_stack helper, from Dave.

3) Add a bpf_snprintf helper, from Florent.

4) A bunch of miscellaneous improvements from many developers.
====================

Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>bpf: Add a bpf_snprintf helper</title>
<updated>2021-04-19T22:27:36Z</updated>
<author>
<name>Florent Revest</name>
<email>revest@chromium.org</email>
</author>
<published>2021-04-19T15:52:40Z</published>
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The implementation takes inspiration from the existing bpf_trace_printk
helper but there are a few differences:

To allow for a large number of format-specifiers, parameters are
provided in an array, like in bpf_seq_printf.

Because the output string takes two arguments and the array of
parameters also takes two arguments, the format string needs to fit in
one argument. Thankfully, ARG_PTR_TO_CONST_STR is guaranteed to point to
a zero-terminated read-only map so we don't need a format string length
arg.

Because the format-string is known at verification time, we also do
a first pass of format string validation in the verifier logic. This
makes debugging easier.

Signed-off-by: Florent Revest &lt;revest@chromium.org&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Acked-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20210419155243.1632274-4-revest@chromium.org
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