<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/powerpc/perf, branch vsnprintf</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'powerpc-6.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux</title>
<updated>2024-11-23T18:44:31+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-11-23T18:44:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=42d9e8b7ccddee75989283cf7477305cfe3776ff'/>
<id>42d9e8b7ccddee75989283cf7477305cfe3776ff</id>
<content type='text'>
Pull powerpc updates from Michael Ellerman:

 - Rework kfence support for the HPT MMU to work on systems with &gt;= 16TB
   of RAM.

 - Remove the powerpc "maple" platform, used by the "Yellow Dog
   Powerstation".

 - Add support for DYNAMIC_FTRACE_WITH_CALL_OPS,
   DYNAMIC_FTRACE_WITH_DIRECT_CALLS &amp; BPF Trampolines.

 - Add support for running KVM nested guests on Power11.

 - Other small features, cleanups and fixes.

Thanks to Amit Machhiwal, Arnd Bergmann, Christophe Leroy, Costa
Shulyupin, David Hunter, David Wang, Disha Goel, Gautam Menghani, Geert
Uytterhoeven, Hari Bathini, Julia Lawall, Kajol Jain, Keith Packard,
Lukas Bulwahn, Madhavan Srinivasan, Markus Elfring, Michal Suchanek,
Ming Lei, Mukesh Kumar Chaurasiya, Nathan Chancellor, Naveen N Rao,
Nicholas Piggin, Nysal Jan K.A, Paulo Miguel Almeida, Pavithra Prakash,
Ritesh Harjani (IBM), Rob Herring (Arm), Sachin P Bappalige, Shen
Lichuan, Simon Horman, Sourabh Jain, Thomas Weißschuh, Thorsten Blum,
Thorsten Leemhuis, Venkat Rao Bagalkote, Zhang Zekun, and zhang jiao.

* tag 'powerpc-6.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (89 commits)
  EDAC/powerpc: Remove PPC_MAPLE drivers
  powerpc/perf: Add per-task/process monitoring to vpa_pmu driver
  powerpc/kvm: Add vpa latency counters to kvm_vcpu_arch
  docs: ABI: sysfs-bus-event_source-devices-vpa-pmu: Document sysfs event format entries for vpa_pmu
  powerpc/perf: Add perf interface to expose vpa counters
  MAINTAINERS: powerpc: Mark Maddy as "M"
  powerpc/Makefile: Allow overriding CPP
  powerpc-km82xx.c: replace of_node_put() with __free
  ps3: Correct some typos in comments
  powerpc/kexec: Fix return of uninitialized variable
  macintosh: Use common error handling code in via_pmu_led_init()
  powerpc/powermac: Use of_property_match_string() in pmac_has_backlight_type()
  powerpc: remove dead config options for MPC85xx platform support
  powerpc/xive: Use cpumask_intersects()
  selftests/powerpc: Remove the path after initialization.
  powerpc/xmon: symbol lookup length fixed
  powerpc/ep8248e: Use %pa to format resource_size_t
  powerpc/ps3: Reorganize kerneldoc parameter names
  KVM: PPC: Book3S HV: Fix kmv -&gt; kvm typo
  powerpc/sstep: make emulate_vsx_load and emulate_vsx_store static
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull powerpc updates from Michael Ellerman:

 - Rework kfence support for the HPT MMU to work on systems with &gt;= 16TB
   of RAM.

 - Remove the powerpc "maple" platform, used by the "Yellow Dog
   Powerstation".

 - Add support for DYNAMIC_FTRACE_WITH_CALL_OPS,
   DYNAMIC_FTRACE_WITH_DIRECT_CALLS &amp; BPF Trampolines.

 - Add support for running KVM nested guests on Power11.

 - Other small features, cleanups and fixes.

Thanks to Amit Machhiwal, Arnd Bergmann, Christophe Leroy, Costa
Shulyupin, David Hunter, David Wang, Disha Goel, Gautam Menghani, Geert
Uytterhoeven, Hari Bathini, Julia Lawall, Kajol Jain, Keith Packard,
Lukas Bulwahn, Madhavan Srinivasan, Markus Elfring, Michal Suchanek,
Ming Lei, Mukesh Kumar Chaurasiya, Nathan Chancellor, Naveen N Rao,
Nicholas Piggin, Nysal Jan K.A, Paulo Miguel Almeida, Pavithra Prakash,
Ritesh Harjani (IBM), Rob Herring (Arm), Sachin P Bappalige, Shen
Lichuan, Simon Horman, Sourabh Jain, Thomas Weißschuh, Thorsten Blum,
Thorsten Leemhuis, Venkat Rao Bagalkote, Zhang Zekun, and zhang jiao.

* tag 'powerpc-6.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (89 commits)
  EDAC/powerpc: Remove PPC_MAPLE drivers
  powerpc/perf: Add per-task/process monitoring to vpa_pmu driver
  powerpc/kvm: Add vpa latency counters to kvm_vcpu_arch
  docs: ABI: sysfs-bus-event_source-devices-vpa-pmu: Document sysfs event format entries for vpa_pmu
  powerpc/perf: Add perf interface to expose vpa counters
  MAINTAINERS: powerpc: Mark Maddy as "M"
  powerpc/Makefile: Allow overriding CPP
  powerpc-km82xx.c: replace of_node_put() with __free
  ps3: Correct some typos in comments
  powerpc/kexec: Fix return of uninitialized variable
  macintosh: Use common error handling code in via_pmu_led_init()
  powerpc/powermac: Use of_property_match_string() in pmac_has_backlight_type()
  powerpc: remove dead config options for MPC85xx platform support
  powerpc/xive: Use cpumask_intersects()
  selftests/powerpc: Remove the path after initialization.
  powerpc/xmon: symbol lookup length fixed
  powerpc/ep8248e: Use %pa to format resource_size_t
  powerpc/ps3: Reorganize kerneldoc parameter names
  KVM: PPC: Book3S HV: Fix kmv -&gt; kvm typo
  powerpc/sstep: make emulate_vsx_load and emulate_vsx_store static
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2024-11-23T17:58:07+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-11-23T17:58:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5c00ff742bf5caf85f60e1c73999f99376fb865d'/>
<id>5c00ff742bf5caf85f60e1c73999f99376fb865d</id>
<content type='text'>
Pull MM updates from Andrew Morton:

 - The series "zram: optimal post-processing target selection" from
   Sergey Senozhatsky improves zram's post-processing selection
   algorithm. This leads to improved memory savings.

 - Wei Yang has gone to town on the mapletree code, contributing several
   series which clean up the implementation:
	- "refine mas_mab_cp()"
	- "Reduce the space to be cleared for maple_big_node"
	- "maple_tree: simplify mas_push_node()"
	- "Following cleanup after introduce mas_wr_store_type()"
	- "refine storing null"

 - The series "selftests/mm: hugetlb_fault_after_madv improvements" from
   David Hildenbrand fixes this selftest for s390.

 - The series "introduce pte_offset_map_{ro|rw}_nolock()" from Qi Zheng
   implements some rationaizations and cleanups in the page mapping
   code.

 - The series "mm: optimize shadow entries removal" from Shakeel Butt
   optimizes the file truncation code by speeding up the handling of
   shadow entries.

 - The series "Remove PageKsm()" from Matthew Wilcox completes the
   migration of this flag over to being a folio-based flag.

 - The series "Unify hugetlb into arch_get_unmapped_area functions" from
   Oscar Salvador implements a bunch of consolidations and cleanups in
   the hugetlb code.

 - The series "Do not shatter hugezeropage on wp-fault" from Dev Jain
   takes away the wp-fault time practice of turning a huge zero page
   into small pages. Instead we replace the whole thing with a THP. More
   consistent cleaner and potentiall saves a large number of pagefaults.

 - The series "percpu: Add a test case and fix for clang" from Andy
   Shevchenko enhances and fixes the kernel's built in percpu test code.

 - The series "mm/mremap: Remove extra vma tree walk" from Liam Howlett
   optimizes mremap() by avoiding doing things which we didn't need to
   do.

 - The series "Improve the tmpfs large folio read performance" from
   Baolin Wang teaches tmpfs to copy data into userspace at the folio
   size rather than as individual pages. A 20% speedup was observed.

 - The series "mm/damon/vaddr: Fix issue in
   damon_va_evenly_split_region()" fro Zheng Yejian fixes DAMON
   splitting.

 - The series "memcg-v1: fully deprecate charge moving" from Shakeel
   Butt removes the long-deprecated memcgv2 charge moving feature.

 - The series "fix error handling in mmap_region() and refactor" from
   Lorenzo Stoakes cleanup up some of the mmap() error handling and
   addresses some potential performance issues.

 - The series "x86/module: use large ROX pages for text allocations"
   from Mike Rapoport teaches x86 to use large pages for
   read-only-execute module text.

 - The series "page allocation tag compression" from Suren Baghdasaryan
   is followon maintenance work for the new page allocation profiling
   feature.

 - The series "page-&gt;index removals in mm" from Matthew Wilcox remove
   most references to page-&gt;index in mm/. A slow march towards shrinking
   struct page.

 - The series "damon/{self,kunit}tests: minor fixups for DAMON debugfs
   interface tests" from Andrew Paniakin performs maintenance work for
   DAMON's self testing code.

 - The series "mm: zswap swap-out of large folios" from Kanchana Sridhar
   improves zswap's batching of compression and decompression. It is a
   step along the way towards using Intel IAA hardware acceleration for
   this zswap operation.

 - The series "kasan: migrate the last module test to kunit" from
   Sabyrzhan Tasbolatov completes the migration of the KASAN built-in
   tests over to the KUnit framework.

 - The series "implement lightweight guard pages" from Lorenzo Stoakes
   permits userapace to place fault-generating guard pages within a
   single VMA, rather than requiring that multiple VMAs be created for
   this. Improved efficiencies for userspace memory allocators are
   expected.

 - The series "memcg: tracepoint for flushing stats" from JP Kobryn uses
   tracepoints to provide increased visibility into memcg stats flushing
   activity.

 - The series "zram: IDLE flag handling fixes" from Sergey Senozhatsky
   fixes a zram buglet which potentially affected performance.

 - The series "mm: add more kernel parameters to control mTHP" from
   Maíra Canal enhances our ability to control/configuremultisize THP
   from the kernel boot command line.

 - The series "kasan: few improvements on kunit tests" from Sabyrzhan
   Tasbolatov has a couple of fixups for the KASAN KUnit tests.

 - The series "mm/list_lru: Split list_lru lock into per-cgroup scope"
   from Kairui Song optimizes list_lru memory utilization when lockdep
   is enabled.

* tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (215 commits)
  cma: enforce non-zero pageblock_order during cma_init_reserved_mem()
  mm/kfence: add a new kunit test test_use_after_free_read_nofault()
  zram: fix NULL pointer in comp_algorithm_show()
  memcg/hugetlb: add hugeTLB counters to memcg
  vmstat: call fold_vm_zone_numa_events() before show per zone NUMA event
  mm: mmap_lock: check trace_mmap_lock_$type_enabled() instead of regcount
  zram: ZRAM_DEF_COMP should depend on ZRAM
  MAINTAINERS/MEMORY MANAGEMENT: add document files for mm
  Docs/mm/damon: recommend academic papers to read and/or cite
  mm: define general function pXd_init()
  kmemleak: iommu/iova: fix transient kmemleak false positive
  mm/list_lru: simplify the list_lru walk callback function
  mm/list_lru: split the lock to per-cgroup scope
  mm/list_lru: simplify reparenting and initial allocation
  mm/list_lru: code clean up for reparenting
  mm/list_lru: don't export list_lru_add
  mm/list_lru: don't pass unnecessary key parameters
  kasan: add kunit tests for kmalloc_track_caller, kmalloc_node_track_caller
  kasan: change kasan_atomics kunit test as KUNIT_CASE_SLOW
  kasan: use EXPORT_SYMBOL_IF_KUNIT to export symbols
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull MM updates from Andrew Morton:

 - The series "zram: optimal post-processing target selection" from
   Sergey Senozhatsky improves zram's post-processing selection
   algorithm. This leads to improved memory savings.

 - Wei Yang has gone to town on the mapletree code, contributing several
   series which clean up the implementation:
	- "refine mas_mab_cp()"
	- "Reduce the space to be cleared for maple_big_node"
	- "maple_tree: simplify mas_push_node()"
	- "Following cleanup after introduce mas_wr_store_type()"
	- "refine storing null"

 - The series "selftests/mm: hugetlb_fault_after_madv improvements" from
   David Hildenbrand fixes this selftest for s390.

 - The series "introduce pte_offset_map_{ro|rw}_nolock()" from Qi Zheng
   implements some rationaizations and cleanups in the page mapping
   code.

 - The series "mm: optimize shadow entries removal" from Shakeel Butt
   optimizes the file truncation code by speeding up the handling of
   shadow entries.

 - The series "Remove PageKsm()" from Matthew Wilcox completes the
   migration of this flag over to being a folio-based flag.

 - The series "Unify hugetlb into arch_get_unmapped_area functions" from
   Oscar Salvador implements a bunch of consolidations and cleanups in
   the hugetlb code.

 - The series "Do not shatter hugezeropage on wp-fault" from Dev Jain
   takes away the wp-fault time practice of turning a huge zero page
   into small pages. Instead we replace the whole thing with a THP. More
   consistent cleaner and potentiall saves a large number of pagefaults.

 - The series "percpu: Add a test case and fix for clang" from Andy
   Shevchenko enhances and fixes the kernel's built in percpu test code.

 - The series "mm/mremap: Remove extra vma tree walk" from Liam Howlett
   optimizes mremap() by avoiding doing things which we didn't need to
   do.

 - The series "Improve the tmpfs large folio read performance" from
   Baolin Wang teaches tmpfs to copy data into userspace at the folio
   size rather than as individual pages. A 20% speedup was observed.

 - The series "mm/damon/vaddr: Fix issue in
   damon_va_evenly_split_region()" fro Zheng Yejian fixes DAMON
   splitting.

 - The series "memcg-v1: fully deprecate charge moving" from Shakeel
   Butt removes the long-deprecated memcgv2 charge moving feature.

 - The series "fix error handling in mmap_region() and refactor" from
   Lorenzo Stoakes cleanup up some of the mmap() error handling and
   addresses some potential performance issues.

 - The series "x86/module: use large ROX pages for text allocations"
   from Mike Rapoport teaches x86 to use large pages for
   read-only-execute module text.

 - The series "page allocation tag compression" from Suren Baghdasaryan
   is followon maintenance work for the new page allocation profiling
   feature.

 - The series "page-&gt;index removals in mm" from Matthew Wilcox remove
   most references to page-&gt;index in mm/. A slow march towards shrinking
   struct page.

 - The series "damon/{self,kunit}tests: minor fixups for DAMON debugfs
   interface tests" from Andrew Paniakin performs maintenance work for
   DAMON's self testing code.

 - The series "mm: zswap swap-out of large folios" from Kanchana Sridhar
   improves zswap's batching of compression and decompression. It is a
   step along the way towards using Intel IAA hardware acceleration for
   this zswap operation.

 - The series "kasan: migrate the last module test to kunit" from
   Sabyrzhan Tasbolatov completes the migration of the KASAN built-in
   tests over to the KUnit framework.

 - The series "implement lightweight guard pages" from Lorenzo Stoakes
   permits userapace to place fault-generating guard pages within a
   single VMA, rather than requiring that multiple VMAs be created for
   this. Improved efficiencies for userspace memory allocators are
   expected.

 - The series "memcg: tracepoint for flushing stats" from JP Kobryn uses
   tracepoints to provide increased visibility into memcg stats flushing
   activity.

 - The series "zram: IDLE flag handling fixes" from Sergey Senozhatsky
   fixes a zram buglet which potentially affected performance.

 - The series "mm: add more kernel parameters to control mTHP" from
   Maíra Canal enhances our ability to control/configuremultisize THP
   from the kernel boot command line.

 - The series "kasan: few improvements on kunit tests" from Sabyrzhan
   Tasbolatov has a couple of fixups for the KASAN KUnit tests.

 - The series "mm/list_lru: Split list_lru lock into per-cgroup scope"
   from Kairui Song optimizes list_lru memory utilization when lockdep
   is enabled.

* tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (215 commits)
  cma: enforce non-zero pageblock_order during cma_init_reserved_mem()
  mm/kfence: add a new kunit test test_use_after_free_read_nofault()
  zram: fix NULL pointer in comp_algorithm_show()
  memcg/hugetlb: add hugeTLB counters to memcg
  vmstat: call fold_vm_zone_numa_events() before show per zone NUMA event
  mm: mmap_lock: check trace_mmap_lock_$type_enabled() instead of regcount
  zram: ZRAM_DEF_COMP should depend on ZRAM
  MAINTAINERS/MEMORY MANAGEMENT: add document files for mm
  Docs/mm/damon: recommend academic papers to read and/or cite
  mm: define general function pXd_init()
  kmemleak: iommu/iova: fix transient kmemleak false positive
  mm/list_lru: simplify the list_lru walk callback function
  mm/list_lru: split the lock to per-cgroup scope
  mm/list_lru: simplify reparenting and initial allocation
  mm/list_lru: code clean up for reparenting
  mm/list_lru: don't export list_lru_add
  mm/list_lru: don't pass unnecessary key parameters
  kasan: add kunit tests for kmalloc_track_caller, kmalloc_node_track_caller
  kasan: change kasan_atomics kunit test as KUNIT_CASE_SLOW
  kasan: use EXPORT_SYMBOL_IF_KUNIT to export symbols
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc/perf: Add per-task/process monitoring to vpa_pmu driver</title>
<updated>2024-11-19T03:11:30+00:00</updated>
<author>
<name>Kajol Jain</name>
<email>kjain@linux.ibm.com</email>
</author>
<published>2024-11-18T11:41:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f26f9933e3e31b2117b804b6b8932388db88a131'/>
<id>f26f9933e3e31b2117b804b6b8932388db88a131</id>
<content type='text'>
Enhance the vpa_pmu driver with a feature to observe context switch
latency event for both per-task (tid) and per-pid (pid) option.
Couple of new helper functions are added to hide the abstraction of
reading the context switch latency counter from kvm_vcpu_arch struct
and these helper functions are defined in the "kvm/book3s_hv.c".

"PERF_ATTACH_TASK" flag is used to decide whether to read the counter
values from lppaca or kvm_vcpu_arch struct.

Signed-off-by: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Co-developed-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Signed-off-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://patch.msgid.link/20241118114114.208964-4-kjain@linux.ibm.com

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Enhance the vpa_pmu driver with a feature to observe context switch
latency event for both per-task (tid) and per-pid (pid) option.
Couple of new helper functions are added to hide the abstraction of
reading the context switch latency counter from kvm_vcpu_arch struct
and these helper functions are defined in the "kvm/book3s_hv.c".

"PERF_ATTACH_TASK" flag is used to decide whether to read the counter
values from lppaca or kvm_vcpu_arch struct.

Signed-off-by: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Co-developed-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Signed-off-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://patch.msgid.link/20241118114114.208964-4-kjain@linux.ibm.com

</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc/perf: Add perf interface to expose vpa counters</title>
<updated>2024-11-19T03:11:06+00:00</updated>
<author>
<name>Kajol Jain</name>
<email>kjain@linux.ibm.com</email>
</author>
<published>2024-11-18T11:41:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=176cda0619b6c17a553625f6e2fcbc3981ad667d'/>
<id>176cda0619b6c17a553625f6e2fcbc3981ad667d</id>
<content type='text'>
To support performance measurement for KVM on PowerVM(KoP)
feature, PowerVM hypervisor has added couple of new software
counters in Virtual Process Area(VPA) of the partition.

Commit e1f288d2f9c69 ("KVM: PPC: Book3S HV nestedv2: Add
support for reading VPA counters for pseries guests")
have updated the paca fields with corresponding changes.

Proposed perf interface is to expose these new software
counters for monitoring of context switch latencies and
runtime aggregate. Perf interface driver is called
"vpa_pmu" and it has dependency on KVM and perf, hence
added new config called "VPA_PMU" which depends on
"CONFIG_KVM_BOOK3S_64_HV" and "CONFIG_HV_PERF_CTRS".
Since, kvm and kvm_host are currently compiled as built-in
modules, this perf interface takes the same path and
registered as a module.

vpa_pmu perf interface needs access to some of the kvm
functions and structures like kvmhv_get_l2_counters_status(),
hence kvm_book3s_64.h and kvm_ppc.h are included.
Below are the events added to monitor KoP:

  vpa_pmu/l1_to_l2_lat/
  vpa_pmu/l2_to_l1_lat/
  vpa_pmu/l2_runtime_agg/

and vpa_pmu driver supports only per-cpu monitoring with this patch.
Example usage:

[command]# perf stat -e vpa_pmu/l1_to_l2_lat/ -a -I 1000
     1.001017682            727,200      vpa_pmu/l1_to_l2_lat/
     2.003540491          1,118,824      vpa_pmu/l1_to_l2_lat/
     3.005699458          1,919,726      vpa_pmu/l1_to_l2_lat/
     4.007827011          2,364,630      vpa_pmu/l1_to_l2_lat/

Signed-off-by: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Co-developed-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Signed-off-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://patch.msgid.link/20241118114114.208964-1-kjain@linux.ibm.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
To support performance measurement for KVM on PowerVM(KoP)
feature, PowerVM hypervisor has added couple of new software
counters in Virtual Process Area(VPA) of the partition.

Commit e1f288d2f9c69 ("KVM: PPC: Book3S HV nestedv2: Add
support for reading VPA counters for pseries guests")
have updated the paca fields with corresponding changes.

Proposed perf interface is to expose these new software
counters for monitoring of context switch latencies and
runtime aggregate. Perf interface driver is called
"vpa_pmu" and it has dependency on KVM and perf, hence
added new config called "VPA_PMU" which depends on
"CONFIG_KVM_BOOK3S_64_HV" and "CONFIG_HV_PERF_CTRS".
Since, kvm and kvm_host are currently compiled as built-in
modules, this perf interface takes the same path and
registered as a module.

vpa_pmu perf interface needs access to some of the kvm
functions and structures like kvmhv_get_l2_counters_status(),
hence kvm_book3s_64.h and kvm_ppc.h are included.
Below are the events added to monitor KoP:

  vpa_pmu/l1_to_l2_lat/
  vpa_pmu/l2_to_l1_lat/
  vpa_pmu/l2_runtime_agg/

and vpa_pmu driver supports only per-cpu monitoring with this patch.
Example usage:

[command]# perf stat -e vpa_pmu/l1_to_l2_lat/ -a -I 1000
     1.001017682            727,200      vpa_pmu/l1_to_l2_lat/
     2.003540491          1,118,824      vpa_pmu/l1_to_l2_lat/
     3.005699458          1,919,726      vpa_pmu/l1_to_l2_lat/
     4.007827011          2,364,630      vpa_pmu/l1_to_l2_lat/

Signed-off-by: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Co-developed-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Signed-off-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://patch.msgid.link/20241118114114.208964-1-kjain@linux.ibm.com
</pre>
</div>
</content>
</entry>
<entry>
<title>perf/powerpc: Use perf_arch_instruction_pointer()</title>
<updated>2024-11-14T09:40:01+00:00</updated>
<author>
<name>Colton Lewis</name>
<email>coltonlewis@google.com</email>
</author>
<published>2024-11-13T19:01:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3e807cf07d96eedb57d91a91f611f828e8918aab'/>
<id>3e807cf07d96eedb57d91a91f611f828e8918aab</id>
<content type='text'>
Make sure PowerPC uses the arch-specific function now that those have
been reorganized.

Signed-off-by: Colton Lewis &lt;coltonlewis@google.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Reviewed-by: Oliver Upton &lt;oliver.upton@linux.dev&gt;
Acked-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Link: https://lore.kernel.org/r/20241113190156.2145593-4-coltonlewis@google.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Make sure PowerPC uses the arch-specific function now that those have
been reorganized.

Signed-off-by: Colton Lewis &lt;coltonlewis@google.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Reviewed-by: Oliver Upton &lt;oliver.upton@linux.dev&gt;
Acked-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Link: https://lore.kernel.org/r/20241113190156.2145593-4-coltonlewis@google.com
</pre>
</div>
</content>
</entry>
<entry>
<title>perf/core: Hoist perf_instruction_pointer() and perf_misc_flags()</title>
<updated>2024-11-14T09:40:01+00:00</updated>
<author>
<name>Colton Lewis</name>
<email>coltonlewis@google.com</email>
</author>
<published>2024-11-13T19:01:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=04782e63917dbcb60932fe93df52c4a4e3859d07'/>
<id>04782e63917dbcb60932fe93df52c4a4e3859d07</id>
<content type='text'>
For clarity, rename the arch-specific definitions of these functions
to perf_arch_* to denote they are arch-specifc. Define the
generic-named functions in one place where they can call the
arch-specific ones as needed.

Signed-off-by: Colton Lewis &lt;coltonlewis@google.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Reviewed-by: Oliver Upton &lt;oliver.upton@linux.dev&gt;
Acked-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Acked-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Acked-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Acked-by: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Link: https://lore.kernel.org/r/20241113190156.2145593-3-coltonlewis@google.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
For clarity, rename the arch-specific definitions of these functions
to perf_arch_* to denote they are arch-specifc. Define the
generic-named functions in one place where they can call the
arch-specific ones as needed.

Signed-off-by: Colton Lewis &lt;coltonlewis@google.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Reviewed-by: Oliver Upton &lt;oliver.upton@linux.dev&gt;
Acked-by: Thomas Richter &lt;tmricht@linux.ibm.com&gt;
Acked-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Acked-by: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Acked-by: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Link: https://lore.kernel.org/r/20241113190156.2145593-3-coltonlewis@google.com
</pre>
</div>
</content>
</entry>
<entry>
<title>asm-generic: introduce text-patching.h</title>
<updated>2024-11-07T22:25:15+00:00</updated>
<author>
<name>Mike Rapoport (Microsoft)</name>
<email>rppt@kernel.org</email>
</author>
<published>2024-10-23T16:27:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=0c3beacf681ec897e0b36685a9b49d01f5cb2dfb'/>
<id>0c3beacf681ec897e0b36685a9b49d01f5cb2dfb</id>
<content type='text'>
Several architectures support text patching, but they name the header
files that declare patching functions differently.

Make all such headers consistently named text-patching.h and add an empty
header in asm-generic for architectures that do not support text patching.

Link: https://lkml.kernel.org/r/20241023162711.2579610-4-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) &lt;rppt@kernel.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Acked-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt; # m68k
Acked-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Reviewed-by: Luis Chamberlain &lt;mcgrof@kernel.org&gt;
Tested-by: kdevops &lt;kdevops@lists.linux.dev&gt;
Cc: Andreas Larsson &lt;andreas@gaisler.com&gt;
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Cc: Brian Cain &lt;bcain@quicinc.com&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: Dinh Nguyen &lt;dinguyen@kernel.org&gt;
Cc: Guo Ren &lt;guoren@kernel.org&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: Huacai Chen &lt;chenhuacai@kernel.org&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Johannes Berg &lt;johannes@sipsolutions.net&gt;
Cc: John Paul Adrian Glaubitz &lt;glaubitz@physik.fu-berlin.de&gt;
Cc: Kent Overstreet &lt;kent.overstreet@linux.dev&gt;
Cc: Liam R. Howlett &lt;Liam.Howlett@Oracle.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Cc: Matt Turner &lt;mattst88@gmail.com&gt;
Cc: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Michal Simek &lt;monstr@monstr.eu&gt;
Cc: Oleg Nesterov &lt;oleg@redhat.com&gt;
Cc: Palmer Dabbelt &lt;palmer@dabbelt.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Richard Weinberger &lt;richard@nod.at&gt;
Cc: Russell King &lt;linux@armlinux.org.uk&gt;
Cc: Song Liu &lt;song@kernel.org&gt;
Cc: Stafford Horne &lt;shorne@gmail.com&gt;
Cc: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: Thomas Bogendoerfer &lt;tsbogend@alpha.franken.de&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Uladzislau Rezki (Sony) &lt;urezki@gmail.com&gt;
Cc: Vineet Gupta &lt;vgupta@kernel.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Several architectures support text patching, but they name the header
files that declare patching functions differently.

Make all such headers consistently named text-patching.h and add an empty
header in asm-generic for architectures that do not support text patching.

Link: https://lkml.kernel.org/r/20241023162711.2579610-4-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) &lt;rppt@kernel.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Acked-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt; # m68k
Acked-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Reviewed-by: Luis Chamberlain &lt;mcgrof@kernel.org&gt;
Tested-by: kdevops &lt;kdevops@lists.linux.dev&gt;
Cc: Andreas Larsson &lt;andreas@gaisler.com&gt;
Cc: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Borislav Petkov (AMD) &lt;bp@alien8.de&gt;
Cc: Brian Cain &lt;bcain@quicinc.com&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: Dinh Nguyen &lt;dinguyen@kernel.org&gt;
Cc: Guo Ren &lt;guoren@kernel.org&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: Huacai Chen &lt;chenhuacai@kernel.org&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Johannes Berg &lt;johannes@sipsolutions.net&gt;
Cc: John Paul Adrian Glaubitz &lt;glaubitz@physik.fu-berlin.de&gt;
Cc: Kent Overstreet &lt;kent.overstreet@linux.dev&gt;
Cc: Liam R. Howlett &lt;Liam.Howlett@Oracle.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Cc: Matt Turner &lt;mattst88@gmail.com&gt;
Cc: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Michal Simek &lt;monstr@monstr.eu&gt;
Cc: Oleg Nesterov &lt;oleg@redhat.com&gt;
Cc: Palmer Dabbelt &lt;palmer@dabbelt.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Richard Weinberger &lt;richard@nod.at&gt;
Cc: Russell King &lt;linux@armlinux.org.uk&gt;
Cc: Song Liu &lt;song@kernel.org&gt;
Cc: Stafford Horne &lt;shorne@gmail.com&gt;
Cc: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Cc: Suren Baghdasaryan &lt;surenb@google.com&gt;
Cc: Thomas Bogendoerfer &lt;tsbogend@alpha.franken.de&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Uladzislau Rezki (Sony) &lt;urezki@gmail.com&gt;
Cc: Vineet Gupta &lt;vgupta@kernel.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc/perf: Set cpumode flags using sample address</title>
<updated>2024-06-17T12:47:16+00:00</updated>
<author>
<name>Anjali K</name>
<email>anjalik@linux.ibm.com</email>
</author>
<published>2024-05-28T04:03:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=0300a92e96cb393a1891d3b4a0f00b28dde8643b'/>
<id>0300a92e96cb393a1891d3b4a0f00b28dde8643b</id>
<content type='text'>
Currently in some cases, when the sampled instruction address register
latches to a specific address during sampling, the privilege bits
captured in the sampled event register are incorrect.

For example, a snippet from the perf report on a power10 system is:

  Overhead  Address             Command       Shared Object      Symbol
  ........  ..................  ............  .................  .......................
       2.41%  0x7fff9f94a02c      null_syscall  [unknown]          [k] 0x00007fff9f94a02c
       2.20%  0x7fff9f94a02c      null_syscall  libc.so.6          [.] syscall

perf_get_misc_flags() function looks at the privilege bits to return
the corresponding flags to be used for the address symbol and these
privilege bit details are read from the sampled event register. In the
above snippet, address "0x00007fff9f94a02c" is shown as "k" (kernel) due
to the incorrect privilege bits captured in the sampled event register.

To address this case check whether the sampled address is in the kernel
area. Since this is specific to the latest platform, a new pmu flag
is added called "PPMU_P10" and is used to contain the proposed fix.
PPMU_P10_DD1 marked events are also included under PPMU_P10, hence
remove the code specific to PPMU_P10_DD1 marked events.

Signed-off-by: Anjali K &lt;anjalik@linux.ibm.com&gt;
Reviewed-by: Athira Rajeev &lt;atrajeev@linux.vnet.ibm.com &lt;mailto:atrajeev@linux.vnet.ibm.com&gt;&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://msgid.link/20240528040356.2722275-1-anjalik@linux.ibm.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently in some cases, when the sampled instruction address register
latches to a specific address during sampling, the privilege bits
captured in the sampled event register are incorrect.

For example, a snippet from the perf report on a power10 system is:

  Overhead  Address             Command       Shared Object      Symbol
  ........  ..................  ............  .................  .......................
       2.41%  0x7fff9f94a02c      null_syscall  [unknown]          [k] 0x00007fff9f94a02c
       2.20%  0x7fff9f94a02c      null_syscall  libc.so.6          [.] syscall

perf_get_misc_flags() function looks at the privilege bits to return
the corresponding flags to be used for the address symbol and these
privilege bit details are read from the sampled event register. In the
above snippet, address "0x00007fff9f94a02c" is shown as "k" (kernel) due
to the incorrect privilege bits captured in the sampled event register.

To address this case check whether the sampled address is in the kernel
area. Since this is specific to the latest platform, a new pmu flag
is added called "PPMU_P10" and is used to contain the proposed fix.
PPMU_P10_DD1 marked events are also included under PPMU_P10, hence
remove the code specific to PPMU_P10_DD1 marked events.

Signed-off-by: Anjali K &lt;anjalik@linux.ibm.com&gt;
Reviewed-by: Athira Rajeev &lt;atrajeev@linux.vnet.ibm.com &lt;mailto:atrajeev@linux.vnet.ibm.com&gt;&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://msgid.link/20240528040356.2722275-1-anjalik@linux.ibm.com
</pre>
</div>
</content>
</entry>
<entry>
<title>driver core: Add device_show_string() helper for sysfs attributes</title>
<updated>2024-05-04T15:37:03+00:00</updated>
<author>
<name>Lukas Wunner</name>
<email>lukas@wunner.de</email>
</author>
<published>2024-04-20T20:00:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3cc50d07be10f67aff836f8247a240ec132c6a67'/>
<id>3cc50d07be10f67aff836f8247a240ec132c6a67</id>
<content type='text'>
For drivers wishing to expose an unsigned long, int or bool at a static
memory location in sysfs, the driver core provides ready-made helpers
such as device_show_ulong() to be used as -&gt;show() callback.

Some drivers need to expose a string and so far they all provide their
own -&gt;show() implementation.  arch/powerpc/perf/hv-24x7.c went so far
as to create a device_show_string() helper but kept it private.

Make it public for reuse by other drivers.  The pattern seems to be
sufficiently frequent to merit a public helper.

Add a DEVICE_STRING_ATTR_RO() macro in line with the existing
DEVICE_ULONG_ATTR() and similar macros to ease declaration of string
attributes.

Signed-off-by: Lukas Wunner &lt;lukas@wunner.de&gt;
Acked-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/2e3eaaf2600bb55c0415c23ba301e809403a7aa2.1713608122.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
For drivers wishing to expose an unsigned long, int or bool at a static
memory location in sysfs, the driver core provides ready-made helpers
such as device_show_ulong() to be used as -&gt;show() callback.

Some drivers need to expose a string and so far they all provide their
own -&gt;show() implementation.  arch/powerpc/perf/hv-24x7.c went so far
as to create a device_show_string() helper but kept it private.

Make it public for reuse by other drivers.  The pattern seems to be
sufficiently frequent to merit a public helper.

Add a DEVICE_STRING_ATTR_RO() macro in line with the existing
DEVICE_ULONG_ATTR() and similar macros to ease declaration of string
attributes.

Signed-off-by: Lukas Wunner &lt;lukas@wunner.de&gt;
Acked-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/2e3eaaf2600bb55c0415c23ba301e809403a7aa2.1713608122.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc/hv-gpci: Fix the H_GET_PERF_COUNTER_INFO hcall return value checks</title>
<updated>2024-03-03T12:05:21+00:00</updated>
<author>
<name>Kajol Jain</name>
<email>kjain@linux.ibm.com</email>
</author>
<published>2024-02-29T12:28:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ad86d7ee43b22aa2ed60fb982ae94b285c1be671'/>
<id>ad86d7ee43b22aa2ed60fb982ae94b285c1be671</id>
<content type='text'>
Running event hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=0/
in one of the system throws below error:

 ---Logs---
 # perf list | grep hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles
  hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=?/[Kernel PMU event]

 # perf stat -v -e hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=0/ sleep 2
Using CPUID 00800200
Control descriptor is not initialized
Warning:
hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=0/ event is not supported by the kernel.
failed to read counter hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=0/

 Performance counter stats for 'system wide':

   &lt;not supported&gt;      hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=0/

       2.000700771 seconds time elapsed

The above error is because of the hcall failure as required
permission "Enable Performance Information Collection" is not set.
Based on current code, single_gpci_request function did not check the
error type incase hcall fails and by default returns EINVAL. But we can
have other reasons for hcall failures like H_AUTHORITY/H_PARAMETER with
detail_rc as GEN_BUF_TOO_SMALL, for which we need to act accordingly.

Fix this issue by adding new checks in the single_gpci_request and
h_gpci_event_init functions.

Result after fix patch changes:

 # perf stat -e hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=0/ sleep 2
Error:
No permission to enable hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=0/ event.

Fixes: 220a0c609ad1 ("powerpc/perf: Add support for the hv gpci (get performance counter info) interface")
Reported-by: Akanksha J N &lt;akanksha@linux.ibm.com&gt;
Signed-off-by: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://msgid.link/20240229122847.101162-1-kjain@linux.ibm.com

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Running event hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=0/
in one of the system throws below error:

 ---Logs---
 # perf list | grep hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles
  hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=?/[Kernel PMU event]

 # perf stat -v -e hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=0/ sleep 2
Using CPUID 00800200
Control descriptor is not initialized
Warning:
hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=0/ event is not supported by the kernel.
failed to read counter hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=0/

 Performance counter stats for 'system wide':

   &lt;not supported&gt;      hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=0/

       2.000700771 seconds time elapsed

The above error is because of the hcall failure as required
permission "Enable Performance Information Collection" is not set.
Based on current code, single_gpci_request function did not check the
error type incase hcall fails and by default returns EINVAL. But we can
have other reasons for hcall failures like H_AUTHORITY/H_PARAMETER with
detail_rc as GEN_BUF_TOO_SMALL, for which we need to act accordingly.

Fix this issue by adding new checks in the single_gpci_request and
h_gpci_event_init functions.

Result after fix patch changes:

 # perf stat -e hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=0/ sleep 2
Error:
No permission to enable hv_gpci/dispatch_timebase_by_processor_processor_time_in_timebase_cycles,phys_processor_idx=0/ event.

Fixes: 220a0c609ad1 ("powerpc/perf: Add support for the hv gpci (get performance counter info) interface")
Reported-by: Akanksha J N &lt;akanksha@linux.ibm.com&gt;
Signed-off-by: Kajol Jain &lt;kjain@linux.ibm.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://msgid.link/20240229122847.101162-1-kjain@linux.ibm.com

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