Re: [PATCH v3 00/20] Remove PERF_HAVE_DWARF_REGS

From: Namhyung Kim <namhyung@kernel.org>
To: Ian Rogers <irogers@google.com>,
	"Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Kan Liang <kan.liang@linux.intel.com>,
	John Garry <john.g.garry@oracle.com>,
	Will Deacon <will@kernel.org>,
	James Clark <james.clark@linaro.org>,
	Mike Leach <mike.leach@linaro.org>, Leo Yan <leo.yan@linux.dev>,
	Guo Ren <guoren@kernel.org>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>, Nick Terrell <terrelln@fb.com>,
	Changbin Du <changbin.du@huawei.com>,
	Guilherme Amadio <amadio@gentoo.org>,
	Yang Jihong <yangjihong@bytedance.com>,
	Aditya Gupta <adityag@linux.ibm.com>,
	Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Bibo Mao <maobibo@loongson.cn>,
	Huacai Chen <chenhuacai@kernel.org>,
	Kajol Jain <kjain@linux.ibm.com>,
	Atish Patra <atishp@rivosinc.com>,
	Shenlin Liang <liangshenlin@eswincomputing.com>,
	Anup Patel <anup@brainfault.org>,
	Oliver Upton <oliver.upton@linux.dev>,
	"Steinar H. Gunderson" <sesse@google.com>,
	"Dr. David Alan Gilbert" <linux@treblig.org>,
	Chen Pei <cp0613@linux.alibaba.com>,
	Dima Kogan <dima@secretsauce.net>,
	Przemek Kitszel <przemyslaw.kitszel@intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	Alexander Lobakin <aleksander.lobakin@intel.com>,
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org,
	linux-riscv@lists.infradead.org
Subject: Re: [PATCH v3 00/20] Remove PERF_HAVE_DWARF_REGS
Date: Thu, 7 Nov 2024 11:29:34 -0800	[thread overview]
Message-ID: <Zy0VHro3wE-ZTKsq@google.com> (raw)
In-Reply-To: <20241017002520.59124-1-irogers@google.com>

Hi all,

On Wed, Oct 16, 2024 at 05:25:00PM -0700, Ian Rogers wrote:
> These changes are on top of:
> https://lore.kernel.org/lkml/20241017001354.56973-1-irogers@google.com/
> 
> Prior to these patches PERF_HAVE_DWARF_REGS indicated the presence of
> dwarf-regs.c in the arch directory. dwarf-regs.c provided upto 4
> functions:
> 
> 1) regs_query_register_offset would translate a register name into a
> pt_regs offset and was used by BPF prologues. BPF prologues existed
> for BPF events and support for these was removed many releases ago.
> This code was dead and could be removed.
> 
> 2) get_arch_regstr duplicated get_dwarf_regstr and so it could be
> removed.  The case for csky was a little more complicated as the ABI
> controlled the string. The callers of get_dwarf_regstr were updated to
> also pass the ELF flags so that on csky the ABI appropriate table
> could be used. As the argument is only used on csky this a no-op for
> everything else.
> 
> 3) get_arch_regnum translated a register name back to a dwarf number
> and only existed on x86 where "al", "ax", "eax" and "rax" could all
> mean register 0. This code was moved to util with similar
> machine/flags logic to get_arch_regstr and for consistency with it.
> 
> 4) get_powerpc_regs a PowerPC specific function used by annotate that
> should really be in util.
> 
> 2 and 3 required the wiring through of the ELF machine and flags in
> callers to get_dwarf_regstr and get_dwarf_regnum. When these values
> weren't dependent on an ELF file a new EM_HOST and EF_HOST were added
> to give the host ELF machine and flags. These 2 #defines got rid of
> the existing separate arch files and #ifdefs.
> 
> v3: These files were separated from the rest of the v2 libdw clean up
>     in:
> https://lore.kernel.org/lkml/CAP-5=fVZH3L-6y_sxLwSmT8WyMXDMFnuqUksNULdQYJCPNBFYw@mail.gmail.com/
> 
> Ian Rogers (20):
>   perf bpf-prologue: Remove unused file
>   perf dwarf-regs: Remove PERF_HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET
>   perf dwarf-regs: Add EM_HOST and EF_HOST defines
>   perf disasm: Add e_machine/e_flags to struct arch
>   perf dwarf-regs: Pass accurate disassembly machine to get_dwarf_regnum
>   perf dwarf-regs: Pass ELF flags to get_dwarf_regstr
>   perf dwarf-regs: Move x86 dwarf-regs out of arch
>   perf arm64: Remove dwarf-regs.c
>   perf arm: Remove dwarf-regs.c
>   perf dwarf-regs: Move csky dwarf-regs out of arch
>   perf loongarch: Remove dwarf-regs.c
>   perf mips: Remove dwarf-regs.c
>   perf dwarf-regs: Move powerpc dwarf-regs out of arch
>   perf riscv: Remove dwarf-regs.c and add dwarf-regs-table.h
>   perf s390: Remove dwarf-regs.c
>   perf sh: Remove dwarf-regs.c
>   perf sparc: Remove dwarf-regs.c
>   perf xtensa: Remove dwarf-regs.c
>   perf dwarf-regs: Remove get_arch_regstr code
>   perf build: Remove PERF_HAVE_DWARF_REGS

These look all good and I'm about to apply the series.

Masami, do you have any remaining concerns?  It'd be nice if you can
give your Reviewed-by.

Thanks,
Namhyug

> 
>  tools/perf/Makefile.config                    |  17 +-
>  tools/perf/arch/arc/annotate/instructions.c   |   2 +
>  tools/perf/arch/arm/Makefile                  |   3 -
>  tools/perf/arch/arm/annotate/instructions.c   |   2 +
>  tools/perf/arch/arm/util/Build                |   2 -
>  tools/perf/arch/arm/util/dwarf-regs.c         |  61 -------
>  tools/perf/arch/arm64/Makefile                |   4 -
>  tools/perf/arch/arm64/annotate/instructions.c |   2 +
>  tools/perf/arch/arm64/util/Build              |   1 -
>  tools/perf/arch/arm64/util/dwarf-regs.c       |  92 -----------
>  tools/perf/arch/csky/Makefile                 |   4 -
>  tools/perf/arch/csky/annotate/instructions.c  |   7 +-
>  tools/perf/arch/csky/util/Build               |   1 -
>  tools/perf/arch/loongarch/Makefile            |   4 -
>  .../arch/loongarch/annotate/instructions.c    |   2 +
>  tools/perf/arch/loongarch/util/Build          |   1 -
>  tools/perf/arch/loongarch/util/dwarf-regs.c   |  44 -----
>  tools/perf/arch/mips/Makefile                 |   4 -
>  tools/perf/arch/mips/annotate/instructions.c  |   2 +
>  tools/perf/arch/mips/util/Build               |   1 -
>  tools/perf/arch/mips/util/dwarf-regs.c        |  38 -----
>  tools/perf/arch/powerpc/Makefile              |   5 -
>  .../perf/arch/powerpc/annotate/instructions.c |   2 +
>  tools/perf/arch/powerpc/util/Build            |   1 -
>  tools/perf/arch/powerpc/util/dwarf-regs.c     | 153 ------------------
>  tools/perf/arch/riscv/Makefile                |   5 +-
>  .../arch/riscv/include/dwarf-regs-table.h     |  42 +++++
>  tools/perf/arch/riscv/util/Build              |   1 -
>  tools/perf/arch/riscv/util/dwarf-regs.c       |  72 ---------
>  .../perf/arch/riscv64/annotate/instructions.c |   2 +
>  tools/perf/arch/s390/Makefile                 |   4 -
>  tools/perf/arch/s390/annotate/instructions.c  |   2 +
>  tools/perf/arch/s390/util/Build               |   1 -
>  tools/perf/arch/s390/util/dwarf-regs.c        |  43 -----
>  tools/perf/arch/sh/Build                      |   1 -
>  tools/perf/arch/sh/Makefile                   |   4 -
>  tools/perf/arch/sh/util/Build                 |   1 -
>  tools/perf/arch/sh/util/dwarf-regs.c          |  41 -----
>  tools/perf/arch/sparc/Build                   |   1 -
>  tools/perf/arch/sparc/Makefile                |   4 -
>  tools/perf/arch/sparc/annotate/instructions.c |   2 +
>  tools/perf/arch/sparc/util/Build              |   1 -
>  tools/perf/arch/sparc/util/dwarf-regs.c       |  39 -----
>  tools/perf/arch/x86/Makefile                  |   4 -
>  tools/perf/arch/x86/annotate/instructions.c   |   3 +-
>  tools/perf/arch/x86/util/Build                |   3 -
>  tools/perf/arch/x86/util/dwarf-regs.c         | 153 ------------------
>  tools/perf/arch/xtensa/Build                  |   1 -
>  tools/perf/arch/xtensa/Makefile               |   4 -
>  tools/perf/arch/xtensa/util/Build             |   1 -
>  tools/perf/arch/xtensa/util/dwarf-regs.c      |  21 ---
>  tools/perf/util/Build                         |   3 +
>  tools/perf/util/annotate.c                    |   6 +-
>  tools/perf/util/bpf-prologue.h                |  37 -----
>  tools/perf/util/disasm.h                      |   4 +
>  .../dwarf-regs.c => util/dwarf-regs-csky.c}   |  19 +--
>  tools/perf/util/dwarf-regs-powerpc.c          |  61 +++++++
>  tools/perf/util/dwarf-regs-x86.c              |  50 ++++++
>  tools/perf/util/dwarf-regs.c                  |  38 +++--
>  tools/perf/util/include/dwarf-regs.h          | 110 ++++++++++---
>  tools/perf/util/probe-finder.c                |  13 +-
>  tools/perf/util/probe-finder.h                |   3 +-
>  62 files changed, 328 insertions(+), 927 deletions(-)
>  delete mode 100644 tools/perf/arch/arm/util/dwarf-regs.c
>  delete mode 100644 tools/perf/arch/arm64/util/dwarf-regs.c
>  delete mode 100644 tools/perf/arch/csky/Makefile
>  delete mode 100644 tools/perf/arch/loongarch/util/dwarf-regs.c
>  delete mode 100644 tools/perf/arch/mips/util/dwarf-regs.c
>  delete mode 100644 tools/perf/arch/powerpc/util/dwarf-regs.c
>  create mode 100644 tools/perf/arch/riscv/include/dwarf-regs-table.h
>  delete mode 100644 tools/perf/arch/riscv/util/dwarf-regs.c
>  delete mode 100644 tools/perf/arch/s390/util/dwarf-regs.c
>  delete mode 100644 tools/perf/arch/sh/Build
>  delete mode 100644 tools/perf/arch/sh/Makefile
>  delete mode 100644 tools/perf/arch/sh/util/Build
>  delete mode 100644 tools/perf/arch/sh/util/dwarf-regs.c
>  delete mode 100644 tools/perf/arch/sparc/Build
>  delete mode 100644 tools/perf/arch/sparc/util/Build
>  delete mode 100644 tools/perf/arch/sparc/util/dwarf-regs.c
>  delete mode 100644 tools/perf/arch/x86/util/dwarf-regs.c
>  delete mode 100644 tools/perf/arch/xtensa/Build
>  delete mode 100644 tools/perf/arch/xtensa/Makefile
>  delete mode 100644 tools/perf/arch/xtensa/util/Build
>  delete mode 100644 tools/perf/arch/xtensa/util/dwarf-regs.c
>  delete mode 100644 tools/perf/util/bpf-prologue.h
>  rename tools/perf/{arch/csky/util/dwarf-regs.c => util/dwarf-regs-csky.c} (74%)
>  create mode 100644 tools/perf/util/dwarf-regs-powerpc.c
>  create mode 100644 tools/perf/util/dwarf-regs-x86.c
> 
> -- 
> 2.47.0.105.g07ac214952-goog
> 