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Author SHA1 Message Date
Dapeng Mi
16dccbb842 perf regs: Remove __weak attributive arch__xxx_reg_mask() functions 
Currently, some architecture-specific perf-regs functions, such as
arch__intr_reg_mask() and arch__user_reg_mask(), are defined with the
__weak attribute.

This approach ensures that only functions matching the architecture of
the build/run host are compiled and executed, reducing build time and
binary size.

However, this __weak attribute restricts these functions to be called
only on the same architecture, preventing cross-architecture
functionality.

For example, a perf.data file captured on x86 cannot be parsed on an ARM
platform.

To address this limitation, this patch removes the __weak attribute from
these perf-regs functions.

The architecture-specific code is moved from the arch/ directory to the
util/perf-regs-arch/ directory.

The appropriate architectural functions are then called based on the
EM_HOST.

No functional changes are intended.

Suggested-by: Ian Rogers <irogers@google.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Guo Ren <guoren@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <pjw@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Falcon <thomas.falcon@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Xudong Hao <xudong.hao@intel.com>
Cc: Zide Chen <zide.chen@intel.com>
[ Fixed up somme fuzz with s390 and riscv Build files wrt removing perf_regs.o ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2026-02-06 12:16:09 -03:00
Ian Rogers
ceea279f93 perf kvm stat: Remove use of the arch directory 
`perf kvm stat` supports record and report options.

By using the arch directory a report for a different machine type cannot
be supported.

Move the kvm-stat code out of the arch directory and into
util/kvm-stat-arch following the pattern of perf-regs and dwarf-regs.

Avoid duplicate symbols by renaming functions to have the architecture
name within them.

For global variables, wrap them in an architecture specific function.
Selecting the architecture to use with `perf kvm stat` is selected by
EM_HOST, ie no different than before the change.

Later the ELF machine can be determined from the session or a header
feature (ie EM_HOST at the time of the record).

The build and #define HAVE_KVM_STAT_SUPPORT is now redundant so remove
across Makefiles and in the build.

Opportunistically constify architectural structs and arrays.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Aditya Bodkhe <aditya.b1@linux.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Jones <ajones@ventanamicro.com>
Cc: Anubhav Shelat <ashelat@redhat.com>
Cc: Anup Patel <anup@brainfault.org>
Cc: Athira Rajeev <atrajeev@linux.ibm.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Chun-Tse Shao <ctshao@google.com>
Cc: Dapeng Mi <dapeng1.mi@linux.intel.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <pjw@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quan Zhou <zhouquan@iscas.ac.cn>
Cc: Shimin Guo <shimin.guo@skydio.com>
Cc: Swapnil Sapkal <swapnil.sapkal@amd.com>
Cc: Thomas Falcon <thomas.falcon@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yunseong Kim <ysk@kzalloc.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2026-02-03 18:01:27 -03:00
Shimin Guo
e62fae9d9e perf unwind-libdw: Fix a cross-arch unwinding bug 
The set_initial_registers field of Dwfl_Thread_Callbacks needs to be set
according to the arch of the stack samples being analyzed, not the arch
that perf itself is built for.

Currently perf fails to unwind stack samples collected from archs
different from that of the host perf is running on.

This patch moves the arch-specific implementations of set_initial_registers
from tools/perf/arch to tools/perf/utli/unwind-libdw-arch, similar to the
way the perf-regs-arch folder contains arch-specific functions related to
registers, and chooses the implementation based on the arch of the data
being processed.

Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Shimin Guo <shimin.guo@skydio.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Aditya Bodkhe <aditya.b1@linux.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.ibm.com>
Cc: Chun-Tse Shao <ctshao@google.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Dr. David Alan Gilbert <linux@treblig.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Haibo Xu <haibo1.xu@intel.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Krzysztof Łopatowski <krzysztof.m.lopatowski@gmail.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Mark Wielaard <mark@klomp.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <pjw@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergei Trofimovich <slyich@gmail.com>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Thomas Falcon <thomas.falcon@intel.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2026-01-20 13:00:39 -03:00
Ian Rogers
a90c451918 perf riscv: Remove dwarf-regs.c and add dwarf-regs-table.h 
The file just provides the function get_arch_regstr, however, if in
the only caller get_dwarf_regstr EM_HOST is used for the EM_NONE case,
and the register table is provided in a header file, the function can
never be called. So remove as dead code. Tidy up the EM_NONE cases for
riscv in dwarf-regs.c.

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Cc: Anup Patel <anup@brainfault.org>
Cc: Yang Jihong <yangjihong@bytedance.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Shenlin Liang <liangshenlin@eswincomputing.com>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Guilherme Amadio <amadio@gentoo.org>
Cc: Steinar H. Gunderson <sesse@google.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: James Clark <james.clark@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Chen Pei <cp0613@linux.alibaba.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Aditya Gupta <adityag@linux.ibm.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-riscv@lists.infradead.org
Cc: Bibo Mao <maobibo@loongson.cn>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Atish Patra <atishp@rivosinc.com>
Cc: Dima Kogan <dima@secretsauce.net>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Dr. David Alan Gilbert <linux@treblig.org>
Cc: linux-csky@vger.kernel.org
Link: https://lore.kernel.org/r/20241108234606.429459-15-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
 2024-11-09 08:39:13 -08:00
Ian Rogers
5455d89bf3 perf build: Rename CONFIG_DWARF to CONFIG_LIBDW 
In Makefile.config for unwinding the name dwarf implies either
libunwind or libdw. Make it clearer that CONFIG_DWARF is really just
defined when libdw is present by renaming to CONFIG_LIBDW.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Leo Yan <leo.yan@arm.com>
Cc: Anup Patel <anup@brainfault.org>
Cc: Yang Jihong <yangjihong@bytedance.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Shenlin Liang <liangshenlin@eswincomputing.com>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Guilherme Amadio <amadio@gentoo.org>
Cc: Steinar H. Gunderson <sesse@google.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: James Clark <james.clark@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Chen Pei <cp0613@linux.alibaba.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Aditya Gupta <adityag@linux.ibm.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-riscv@lists.infradead.org
Cc: Bibo Mao <maobibo@loongson.cn>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Atish Patra <atishp@rivosinc.com>
Cc: Dima Kogan <dima@secretsauce.net>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Dr. David Alan Gilbert <linux@treblig.org>
Cc: linux-csky@vger.kernel.org
Link: https://lore.kernel.org/r/20241017001354.56973-12-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
 2024-10-18 10:17:40 -07:00
Linus Torvalds
2c9b351240 Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm 
Pull kvm updates from Paolo Bonzini:
 "ARM:

   - Initial infrastructure for shadow stage-2 MMUs, as part of nested
     virtualization enablement

   - Support for userspace changes to the guest CTR_EL0 value, enabling
     (in part) migration of VMs between heterogenous hardware

   - Fixes + improvements to pKVM's FF-A proxy, adding support for v1.1
     of the protocol

   - FPSIMD/SVE support for nested, including merged trap configuration
     and exception routing

   - New command-line parameter to control the WFx trap behavior under
     KVM

   - Introduce kCFI hardening in the EL2 hypervisor

   - Fixes + cleanups for handling presence/absence of FEAT_TCRX

   - Miscellaneous fixes + documentation updates

  LoongArch:

   - Add paravirt steal time support

   - Add support for KVM_DIRTY_LOG_INITIALLY_SET

   - Add perf kvm-stat support for loongarch

  RISC-V:

   - Redirect AMO load/store access fault traps to guest

   - perf kvm stat support

   - Use guest files for IMSIC virtualization, when available

  s390:

   - Assortment of tiny fixes which are not time critical

  x86:

   - Fixes for Xen emulation

   - Add a global struct to consolidate tracking of host values, e.g.
     EFER

   - Add KVM_CAP_X86_APIC_BUS_CYCLES_NS to allow configuring the
     effective APIC bus frequency, because TDX

   - Print the name of the APICv/AVIC inhibits in the relevant
     tracepoint

   - Clean up KVM's handling of vendor specific emulation to
     consistently act on "compatible with Intel/AMD", versus checking
     for a specific vendor

   - Drop MTRR virtualization, and instead always honor guest PAT on
     CPUs that support self-snoop

   - Update to the newfangled Intel CPU FMS infrastructure

   - Don't advertise IA32_PERF_GLOBAL_OVF_CTRL as an MSR-to-be-saved, as
     it reads '0' and writes from userspace are ignored

   - Misc cleanups

  x86 - MMU:

   - Small cleanups, renames and refactoring extracted from the upcoming
     Intel TDX support

   - Don't allocate kvm_mmu_page.shadowed_translation for shadow pages
     that can't hold leafs SPTEs

   - Unconditionally drop mmu_lock when allocating TDP MMU page tables
     for eager page splitting, to avoid stalling vCPUs when splitting
     huge pages

   - Bug the VM instead of simply warning if KVM tries to split a SPTE
     that is non-present or not-huge. KVM is guaranteed to end up in a
     broken state because the callers fully expect a valid SPTE, it's
     all but dangerous to let more MMU changes happen afterwards

  x86 - AMD:

   - Make per-CPU save_area allocations NUMA-aware

   - Force sev_es_host_save_area() to be inlined to avoid calling into
     an instrumentable function from noinstr code

   - Base support for running SEV-SNP guests. API-wise, this includes a
     new KVM_X86_SNP_VM type, encrypting/measure the initial image into
     guest memory, and finalizing it before launching it. Internally,
     there are some gmem/mmu hooks needed to prepare gmem-allocated
     pages before mapping them into guest private memory ranges

     This includes basic support for attestation guest requests, enough
     to say that KVM supports the GHCB 2.0 specification

     There is no support yet for loading into the firmware those signing
     keys to be used for attestation requests, and therefore no need yet
     for the host to provide certificate data for those keys.

     To support fetching certificate data from userspace, a new KVM exit
     type will be needed to handle fetching the certificate from
     userspace.

     An attempt to define a new KVM_EXIT_COCO / KVM_EXIT_COCO_REQ_CERTS
     exit type to handle this was introduced in v1 of this patchset, but
     is still being discussed by community, so for now this patchset
     only implements a stub version of SNP Extended Guest Requests that
     does not provide certificate data

  x86 - Intel:

   - Remove an unnecessary EPT TLB flush when enabling hardware

   - Fix a series of bugs that cause KVM to fail to detect nested
     pending posted interrupts as valid wake eents for a vCPU executing
     HLT in L2 (with HLT-exiting disable by L1)

   - KVM: x86: Suppress MMIO that is triggered during task switch
     emulation

     Explicitly suppress userspace emulated MMIO exits that are
     triggered when emulating a task switch as KVM doesn't support
     userspace MMIO during complex (multi-step) emulation

     Silently ignoring the exit request can result in the
     WARN_ON_ONCE(vcpu->mmio_needed) firing if KVM exits to userspace
     for some other reason prior to purging mmio_needed

     See commit 0dc902267c ("KVM: x86: Suppress pending MMIO write
     exits if emulator detects exception") for more details on KVM's
     limitations with respect to emulated MMIO during complex emulator
     flows

  Generic:

   - Rename the AS_UNMOVABLE flag that was introduced for KVM to
     AS_INACCESSIBLE, because the special casing needed by these pages
     is not due to just unmovability (and in fact they are only
     unmovable because the CPU cannot access them)

   - New ioctl to populate the KVM page tables in advance, which is
     useful to mitigate KVM page faults during guest boot or after live
     migration. The code will also be used by TDX, but (probably) not
     through the ioctl

   - Enable halt poll shrinking by default, as Intel found it to be a
     clear win

   - Setup empty IRQ routing when creating a VM to avoid having to
     synchronize SRCU when creating a split IRQCHIP on x86

   - Rework the sched_in/out() paths to replace kvm_arch_sched_in() with
     a flag that arch code can use for hooking both sched_in() and
     sched_out()

   - Take the vCPU @id as an "unsigned long" instead of "u32" to avoid
     truncating a bogus value from userspace, e.g. to help userspace
     detect bugs

   - Mark a vCPU as preempted if and only if it's scheduled out while in
     the KVM_RUN loop, e.g. to avoid marking it preempted and thus
     writing guest memory when retrieving guest state during live
     migration blackout

  Selftests:

   - Remove dead code in the memslot modification stress test

   - Treat "branch instructions retired" as supported on all AMD Family
     17h+ CPUs

   - Print the guest pseudo-RNG seed only when it changes, to avoid
     spamming the log for tests that create lots of VMs

   - Make the PMU counters test less flaky when counting LLC cache
     misses by doing CLFLUSH{OPT} in every loop iteration"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (227 commits)
  crypto: ccp: Add the SNP_VLEK_LOAD command
  KVM: x86/pmu: Add kvm_pmu_call() to simplify static calls of kvm_pmu_ops
  KVM: x86: Introduce kvm_x86_call() to simplify static calls of kvm_x86_ops
  KVM: x86: Replace static_call_cond() with static_call()
  KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event
  x86/sev: Move sev_guest.h into common SEV header
  KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event
  KVM: x86: Suppress MMIO that is triggered during task switch emulation
  KVM: x86/mmu: Clean up make_huge_page_split_spte() definition and intro
  KVM: x86/mmu: Bug the VM if KVM tries to split a !hugepage SPTE
  KVM: selftests: x86: Add test for KVM_PRE_FAULT_MEMORY
  KVM: x86: Implement kvm_arch_vcpu_pre_fault_memory()
  KVM: x86/mmu: Make kvm_mmu_do_page_fault() return mapped level
  KVM: x86/mmu: Account pf_{fixed,emulate,spurious} in callers of "do page fault"
  KVM: x86/mmu: Bump pf_taken stat only in the "real" page fault handler
  KVM: Add KVM_PRE_FAULT_MEMORY vcpu ioctl to pre-populate guest memory
  KVM: Document KVM_PRE_FAULT_MEMORY ioctl
  mm, virt: merge AS_UNMOVABLE and AS_INACCESSIBLE
  perf kvm: Add kvm-stat for loongarch64
  LoongArch: KVM: Add PV steal time support in guest side
  ...
 2024-07-20 12:41:03 -07:00
Ian Rogers
e467705a9f perf util: Make util its own library 
Make the util directory into its own library. This is done to avoid
compiling code twice, once for the perf tool and once for the perf
python module. For convenience:
  arch/common.c
  scripts/perl/Perf-Trace-Util/Context.c
  scripts/python/Perf-Trace-Util/Context.c
are made part of this library.

Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: James Clark <james.clark@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Cc: Ze Gao <zegao2021@gmail.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Andrei Vagin <avagin@google.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: Björn Roy Baron <bjorn3_gh@protonmail.com>
Cc: Andreas Hindborg <a.hindborg@samsung.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240625214117.953777-7-irogers@google.com
 2024-06-26 11:07:42 -07:00
Shenlin Liang
da7b1b525e perf kvm/riscv: Port perf kvm stat to RISC-V 
'perf kvm stat report/record' generates a statistical analysis of KVM
events and can be used to analyze guest exit reasons.

"report" reports statistical analysis of guest exit events.

To record kvm events on the host:
 # perf kvm stat record -a

To report kvm VM EXIT events:
 # perf kvm stat report --event=vmexit

Signed-off-by: Shenlin Liang <liangshenlin@eswincomputing.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Tested-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20240422080833.8745-3-liangshenlin@eswincomputing.com
Signed-off-by: Anup Patel <anup@brainfault.org>
 2024-06-26 18:37:38 +05:30
Nikita Shubin
25c2e59117 perf tools riscv: Add support for get_cpuid_str function 
The get_cpuid_str function returns the string that contains values of
MVENDORID, MARCHID and MIMPID in hex format separated by coma.

The values themselves are taken from first cpu entry in "/proc/cpuid"
that contains "mvendorid", "marchid" and "mimpid".

Signed-off-by: Nikita Shubin <n.shubin@yadro.com>
Tested-by: Kautuk Consul <kconsul@ventanamicro.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Anup Patel <anup@brainfault.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-riscv@lists.infradead.org
Cc: linux@yadro.com
Link: https://lore.kernel.org/r/20220815132251.25702-2-nikita.shubin@maquefel.me
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2022-10-27 16:37:24 -03:00
Ian Rogers
42466b9f29 perf tools: Avoid 'sample_reg_masks' being const + weak 
Being const + weak breaks with some compilers that constant-propagate
from the weak symbol. This behavior is outside of the specification, but
in LLVM is chosen to match GCC's behavior.

LLVM's implementation was set in this patch:

  f49573d1ee

A const + weak symbol is set to be weak_odr:

  https://llvm.org/docs/LangRef.html

ODR is one definition rule, and given there is one constant definition
constant-propagation is possible. It is possible to get this code to
miscompile with LLVM when applying link time optimization. As compilers
become more aggressive, this is likely to break in more instances.

Move the definition of sample_reg_masks to the conditional part of
perf_regs.h and guard usage with HAVE_PERF_REGS_SUPPORT. This avoids the
weak symbol.

Fix an issue when HAVE_PERF_REGS_SUPPORT isn't defined from patch v1.
In v3, add perf_regs.c for architectures that HAVE_PERF_REGS_SUPPORT but
don't declare sample_regs_masks.

Further notes:

Jiri asked:

  "Is this just a precaution or you actualy saw some breakage?"

Ian answered:

  "We saw a breakage with clang with thinlto enabled for linking. Our
   compiler team had recently seen, and were surprised by, a similar issue
   and were able to dig out the weak ODR issue."

Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: clang-built-linux@googlegroups.com
Cc: Guo Ren <guoren@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: linux-riscv@lists.infradead.org
Cc: Mao Han <han_mao@c-sky.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20191001003623.255186-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 2019-10-10 09:29:33 -03:00
Mao Han
51bc620ba9 riscv: Add support for libdw 
This patch adds support for DWARF register mappings and libdw registers
initialization, which is used by perf callchain analyzing when
--call-graph=dwarf is given.

Signed-off-by: Mao Han <han_mao@c-sky.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: linux-riscv <linux-riscv@lists.infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Guo Ren <guoren@kernel.org>
Tested-by: Greentime Hu <greentime.hu@sifive.com>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
 2019-09-05 00:51:52 -07:00