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From: Conor Dooley <conor@kernel.org>
To: Greg KH <gregkh@linuxfoundation.org>, Evan Green <evan@rivosinc.com>
Cc: Palmer Dabbelt <palmer@rivosinc.com>,
	vineetg@rivosinc.com, heiko@sntech.de, slewis@rivosinc.com,
	Albert Ou <aou@eecs.berkeley.edu>,
	Andrew Bresticker <abrestic@rivosinc.com>,
	Andrew Jones <ajones@ventanamicro.com>,
	Anup Patel <apatel@ventanamicro.com>,
	Arnd Bergmann <arnd@arndb.de>, Atish Patra <atishp@rivosinc.com>,
	Bagas Sanjaya <bagasdotme@gmail.com>,
	Celeste Liu <coelacanthus@outlook.com>,
	Conor Dooley <conor.dooley@microchip.com>,
	Dao Lu <daolu@rivosinc.com>, Guo Ren <guoren@kernel.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	Ruizhe Pan <c141028@gmail.com>,
	Sunil V L <sunilvl@ventanamicro.com>,
	Tobias Klauser <tklauser@distanz.ch>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org
Subject: Re: [PATCH v2 2/6] RISC-V: Add a syscall for HW probing
Date: Tue, 07 Feb 2023 06:32:18 +0000	[thread overview]
Message-ID: <C3C21677-5250-4120-9A4F-24945C1EE51B@kernel.org> (raw)
In-Reply-To: <Y+HsE397cY4HF+5K@kroah.com>

Hey Evan, Greg,


On 7 February 2023 06:13:39 GMT, Greg KH <gregkh@linuxfoundation.org> wrote:
>On Mon, Feb 06, 2023 at 12:14:51PM -0800, Evan Green wrote:
>> We don't have enough space for these all in ELF_HWCAP{,2} and there's no
>> system call that quite does this, so let's just provide an arch-specific
>> one to probe for hardware capabilities.  This currently just provides
>> m{arch,imp,vendor}id, but with the key-value pairs we can pass more in
>> the future.
>
>Ick, this is exactly what sysfs is designed to export in a sane way.
>Why not just use that instead?  The "key" would be the filename, and the
>value the value read from the filename.  If the key is not present, the
>file is not present and it's obvious what is happening, no fancy parsing
>and ABI issues at all.

https://lore.kernel.org/linux-riscv/20221201160614.xpomlqq2fzpzfmcm@kamzik/

This is the sysfs interface that I mentioned drew
suggested on the v1.
I think it fits ~perfectly with what Greg is suggesting too.

>
>Bonus is that you will also properly document all valid key/value pairs
>in Documentation/ABI/ when you do this, so it reinforces what the code
>should be doing correctly.
>
>thanks,
>
>greg k-h

  reply	other threads:[~2023-02-07  6:32 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-06 20:14 [PATCH v2 0/6] RISC-V Hardware Probing User Interface Evan Green
2023-02-06 20:14 ` [PATCH v2 1/6] RISC-V: Move struct riscv_cpuinfo to new header Evan Green
2023-02-14 21:38   ` Conor Dooley
2023-02-14 21:57     ` Evan Green
2023-02-06 20:14 ` [PATCH v2 2/6] RISC-V: Add a syscall for HW probing Evan Green
2023-02-07  6:13   ` Greg KH
2023-02-07  6:32     ` Conor Dooley [this message]
2023-02-09 17:09       ` Evan Green
2023-02-09 17:13         ` Greg KH
2023-02-09 17:22           ` Jessica Clarke
2023-02-10  6:48             ` Greg KH
2023-02-09 18:41           ` Evan Green
2023-02-10  6:50             ` Greg KH
2023-02-07 23:16   ` kernel test robot
2023-02-14 23:51   ` Conor Dooley
2023-02-15  8:04     ` Andrew Jones
2023-02-15 20:49     ` Evan Green
2023-02-15 21:10       ` Conor Dooley
2023-02-15  9:56   ` Arnd Bergmann
2023-02-15 21:14     ` Evan Green
2023-02-15 22:43       ` Jessica Clarke
2023-02-16 13:28         ` Arnd Bergmann
2023-02-16 23:18           ` Evan Green
2023-02-06 20:14 ` [PATCH v2 3/6] RISC-V: hwprobe: Add support for RISCV_HWPROBE_BASE_BEHAVIOR_IMA Evan Green
2023-02-15 21:25   ` Conor Dooley
2023-02-15 22:09   ` Conor Dooley
2023-02-06 20:14 ` [PATCH v2 4/6] dt-bindings: Add RISC-V misaligned access performance Evan Green
2023-02-06 21:49   ` Rob Herring
2023-02-07 17:05   ` Rob Herring
2023-02-08 12:45     ` David Laight
2023-02-09 16:51       ` Palmer Dabbelt
2023-02-28 14:56         ` Rob Herring
2023-02-14 21:26   ` Conor Dooley
2023-02-15 20:50     ` Evan Green
2023-02-06 20:14 ` [PATCH v2 5/6] RISC-V: hwprobe: Support probing of " Evan Green
2023-02-07  7:02   ` kernel test robot
2023-02-15 21:57   ` Conor Dooley
2023-02-18  0:15     ` Evan Green
2023-02-06 20:14 ` [PATCH v2 6/6] selftests: Test the new RISC-V hwprobe interface Evan Green
2023-02-06 21:27   ` Mark Brown
2023-02-09 18:44     ` Evan Green
2023-02-06 21:11 ` [PATCH v2 0/6] RISC-V Hardware Probing User Interface Jessica Clarke
2023-02-06 22:47   ` Heinrich Schuchardt
2023-02-09 16:56     ` Palmer Dabbelt
2023-02-06 22:32 ` Conor Dooley

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