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  1. Sep 11, 2024
  2. Sep 10, 2024
    • Joerg Roedel's avatar
      iommu/amd: Add kernel parameters to limit V1 page-sizes · f0295913
      Joerg Roedel authored
      
      Add two new kernel command line parameters to limit the page-sizes
      used for v1 page-tables:
      
      	nohugepages     - Limits page-sizes to 4KiB
      
      	v2_pgsizes_only - Limits page-sizes to 4Kib/2Mib/1GiB; The
      	                  same as the sizes used with v2 page-tables
      
      This is needed for multiple scenarios. When assigning devices to
      SEV-SNP guests the IOMMU page-sizes need to match the sizes in the RMP
      table, otherwise the device will not be able to access all shared
      memory.
      
      Also, some ATS devices do not work properly with arbitrary IO
      page-sizes as supported by AMD-Vi, so limiting the sizes used by the
      driver is a suitable workaround.
      
      All-in-all, these parameters are only workarounds until the IOMMU core
      and related APIs gather the ability to negotiate the page-sizes in a
      better way.
      
      Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
      Reviewed-by: default avatarVasant Hegde <vasant.hegde@amd.com>
      Link: https://lore.kernel.org/r/20240905072240.253313-1-joro@8bytes.org
      f0295913
  3. Sep 09, 2024
  4. Sep 08, 2024
  5. Sep 06, 2024
    • Robin Murphy's avatar
      perf: Add driver for Arm NI-700 interconnect PMU · 4d5a7680
      Robin Murphy authored
      
      The Arm NI-700 Network-on-Chip Interconnect has a relatively
      straightforward design with a hierarchy of voltage, power, and clock
      domains, where each clock domain then contains a number of interface
      units and a PMU which can monitor events thereon. As such, it begets a
      relatively straightforward driver to interface those PMUs with perf.
      
      Even more so than with arm-cmn, users will require detailed knowledge of
      the wider system topology in order to meaningfully analyse anything,
      since the interconnect itself cannot know what lies beyond the boundary
      of each inscrutably-numbered interface. Given that, for now they are
      also expected to refer to the NI-700 documentation for the relevant
      event IDs to provide as well. An identifier is implemented so we can
      come back and add jevents if anyone really wants to.
      
      Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
      Link: https://lore.kernel.org/r/9933058d0ab8138c78a61cd6852ea5d5ff48e393.1725470837.git.robin.murphy@arm.com
      
      
      Signed-off-by: default avatarWill Deacon <will@kernel.org>
      4d5a7680
  6. Sep 05, 2024
  7. Sep 04, 2024
  8. Sep 02, 2024
  9. Aug 30, 2024
  10. Aug 27, 2024
  11. Aug 26, 2024
    • Jani Nikula's avatar
      Documentation: admin-guide: direct people to bug trackers, if specified · cd0403ad
      Jani Nikula authored
      
      Update bug reporting info in bug-hunting.rst to direct people to
      driver/subsystem bug trackers, if explicitly specified with the
      MAINTAINERS "B:" entry. Use the new get_maintainer.pl --bug option to
      print the info.
      
      Cc: Joe Perches <joe@perches.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
      Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
      Link: https://lore.kernel.org/r/20240815113450.3397499-2-jani.nikula@intel.com
      cd0403ad
    • Thorsten Leemhuis's avatar
      docs: bug-bisect: rewrite to better match the other bisecting text · cbbdb6c6
      Thorsten Leemhuis authored
      
      Rewrite the short document on bisecting kernel bugs. The new text
      improves .config handling, brings a mention of 'git bisect skip', and
      explains what to do after the bisection finished -- including trying a
      revert to verify the result. The rewrite at the same time removes the
      unrelated and outdated section on 'Devices not appearing' and replaces
      some sentences about bug reporting with a pointer to the document
      covering that topic in detail.
      
      This overall brings the approach close to the one in the recently added
      text Documentation/admin-guide/verify-bugs-and-bisect-regressions.rst.
      As those two texts serve a similar purpose for different audiences,
      mention that document in the head of this one and outline when the
      other might be the better one to follow.
      
      Signed-off-by: default avatarThorsten Leemhuis <linux@leemhuis.info>
      Reviewed-by: default avatarPetr Tesarik <petr@tesarici.cz>
      Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
      Link: https://lore.kernel.org/r/74dc0137dcc3e2c05648e885a7bc31ffd39a0890.1724312119.git.linux@leemhuis.info
      cbbdb6c6
    • Steven Rostedt's avatar
      tracing/Documentation: Start a document on how to debug with tracing · 2fcd5aff
      Steven Rostedt authored
      Add a new document Documentation/trace/debugging.rst that will hold
      various ways to debug tracing.
      
      This initial version mentions trace_printk and how to create persistent
      buffers that can last across bootups.
      
      Cc: Masami Hiramatsu <mhiramat@kernel.org>
      Cc: Mark Rutland <mark.rutland@arm.com>
      Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Vincent Donnefort <vdonnefort@google.com>
      Cc: Joel Fernandes <joel@joelfernandes.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Vineeth Pillai <vineeth@bitbyteword.org>
      Cc: Beau Belgrave <beaub@linux.microsoft.com>
      Cc: Alexander Graf <graf@amazon.com>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: "Paul E. McKenney" <paulmck@kernel.org>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Mike Rapoport <rppt@kernel.org>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Ross Zwisler <zwisler@google.com>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Alexander Aring <aahringo@redhat.com>
      Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
      Cc: Tomas Glozar <tglozar@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      Cc: Clark Williams <williams@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: "Jonathan Corbet" <corbet@lwn.net>
      Link: https://lore.kernel.org/20240823014019.702433486@goodmis.org
      
      
      Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
      2fcd5aff
    • Steven Rostedt's avatar
      tracing: Have trace_printk not use binary prints if boot buffer · 9b7bdf6f
      Steven Rostedt authored
      If the persistent boot mapped ring buffer is used for trace_printk(),
      force it to not use the binary versions. trace_printk() by default uses
      bin_printf() that only saves the pointer to the format and not the format
      itself inside the ring buffer. But for a persistent buffer that is read
      after reboot, the pointers to the format strings may not be the same, or
      worse, not even exist! Instead, just force the more robust, but slower,
      version that does the formatting before saving into the ring buffer.
      
      The boot mapped buffer can now be used for trace_printk and friends!
      
      Using the trace_printk() and the persistent buffer was used to debug the
      issue with the osnoise tracer:
      
      Link: https://lore.kernel.org/all/20240822103443.6a6ae051@gandalf.local.home/
      
      Cc: Masami Hiramatsu <mhiramat@kernel.org>
      Cc: Mark Rutland <mark.rutland@arm.com>
      Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Vincent Donnefort <vdonnefort@google.com>
      Cc: Joel Fernandes <joel@joelfernandes.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Vineeth Pillai <vineeth@bitbyteword.org>
      Cc: Beau Belgrave <beaub@linux.microsoft.com>
      Cc: Alexander Graf <graf@amazon.com>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: "Paul E. McKenney" <paulmck@kernel.org>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Mike Rapoport <rppt@kernel.org>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Ross Zwisler <zwisler@google.com>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Alexander Aring <aahringo@redhat.com>
      Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
      Cc: Tomas Glozar <tglozar@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      Cc: Clark Williams <williams@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: "Jonathan Corbet" <corbet@lwn.net>
      Link: https://lore.kernel.org/20240823014019.386925800@goodmis.org
      
      
      Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
      9b7bdf6f
    • Steven Rostedt's avatar
      tracing: Allow trace_printk() to go to other instance buffers · ddb8ea9e
      Steven Rostedt authored
      Currently, trace_printk() just goes to the top level ring buffer. But
      there may be times that it should go to one of the instances created by
      the kernel command line.
      
      Add a new trace_instance flag: traceprintk (also can use "printk" or
      "trace_printk" as people tend to forget the actual flag name).
      
        trace_instance=foo^traceprintk
      
      Will assign the trace_printk to this buffer at boot up.
      
      Cc: Masami Hiramatsu <mhiramat@kernel.org>
      Cc: Mark Rutland <mark.rutland@arm.com>
      Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Vincent Donnefort <vdonnefort@google.com>
      Cc: Joel Fernandes <joel@joelfernandes.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Vineeth Pillai <vineeth@bitbyteword.org>
      Cc: Beau Belgrave <beaub@linux.microsoft.com>
      Cc: Alexander Graf <graf@amazon.com>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: "Paul E. McKenney" <paulmck@kernel.org>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Mike Rapoport <rppt@kernel.org>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Ross Zwisler <zwisler@google.com>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Alexander Aring <aahringo@redhat.com>
      Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
      Cc: Tomas Glozar <tglozar@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      Cc: Clark Williams <williams@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: "Jonathan Corbet" <corbet@lwn.net>
      Link: https://lore.kernel.org/20240823014019.226694946@goodmis.org
      
      
      Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
      ddb8ea9e
    • Steven Rostedt's avatar
      tracing: Add "traceoff" flag to boot time tracing instances · b6fc31b6
      Steven Rostedt authored
      Add a "flags" delimiter (^) to the "trace_instance" kernel command line
      parameter, and add the "traceoff" flag. The format is:
      
         trace_instance=<name>[^<flag1>[^<flag2>]][@<memory>][,<events>]
      
      The code allows for more than one flag to be added, but currently only
      "traceoff" is done so.
      
      The motivation for this change came from debugging with the persistent
      ring buffer and having trace_printk() writing to it. The trace_printk
      calls are always enabled, and the boot after the crash was having the
      unwanted trace_printks from the current boot inject into the ring buffer
      with the trace_printks of the crash kernel, making the output very
      confusing.
      
      Cc: Masami Hiramatsu <mhiramat@kernel.org>
      Cc: Mark Rutland <mark.rutland@arm.com>
      Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Vincent Donnefort <vdonnefort@google.com>
      Cc: Joel Fernandes <joel@joelfernandes.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Vineeth Pillai <vineeth@bitbyteword.org>
      Cc: Beau Belgrave <beaub@linux.microsoft.com>
      Cc: Alexander Graf <graf@amazon.com>
      Cc: Baoquan He <bhe@redhat.com>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: "Paul E. McKenney" <paulmck@kernel.org>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Mike Rapoport <rppt@kernel.org>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: Guenter Roeck <linux@roeck-us.net>
      Cc: Ross Zwisler <zwisler@google.com>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Alexander Aring <aahringo@redhat.com>
      Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
      Cc: Tomas Glozar <tglozar@redhat.com>
      Cc: John Kacur <jkacur@redhat.com>
      Cc: Clark Williams <williams@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: "Jonathan Corbet" <corbet@lwn.net>
      Link: https://lore.kernel.org/20240823014019.053229958@goodmis.org
      
      
      Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
      b6fc31b6
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