Linux-RISC-V Archive on lore.kernel.org
 help / color / mirror / Atom feed
From: Andrew Jones <ajones@ventanamicro.com>
To: linux-riscv@lists.infradead.org
Cc: paul.walmsley@sifive.com, palmer@dabbelt.com,
	aou@eecs.berkeley.edu,  evan@rivosinc.com,
	conor.dooley@microchip.com, apatel@ventanamicro.com
Subject: Re: [PATCH v3 6/6] RISC-V: selftests: Add CBO tests
Date: Mon, 18 Sep 2023 12:41:06 +0200	[thread overview]
Message-ID: <20230918-062f2e7be4d5dab914648c91@orel> (raw)
In-Reply-To: <20230904170220.167816-14-ajones@ventanamicro.com>

On Mon, Sep 04, 2023 at 07:02:27PM +0200, Andrew Jones wrote:
> Add hwprobe test for Zicboz and its block size. Also, when Zicboz is
> present, test that cbo.zero may be issued and works. Additionally
> test that the Zicbom instructions cause SIGILL and also that cbo.zero
> causes SIGILL when Zicboz is not present. Pinning the test to a subset
> of cpus with taskset will also restrict the hwprobe calls to that set.

Palmer pointed out that there's no guarantee to get illegal-instruction
exceptions when Zicbom/Zicboz are not present. Indeed, the unpriv spec
states

"""
 The behavior upon decoding a reserved instruction is UNSPECIFIED.

   Some platforms may require that opcodes reserved for standard use raise
   an illegal-instruction exception. Other platforms may permit reserved
   opcode space be used for non-conforming extensions.
"""

This implies that cannot do the illegal-instruction checks for when
hwprobe reports the extension isn't present. That's a pity, but I
guess I should rip it out. Or, maybe I'll keep it, but only run it
under a command line switch.

Thanks,
drew

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

      parent reply	other threads:[~2023-09-18 10:41 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-04 17:02 [PATCH v3 0/6] RISC-V: Enable cbo.zero in usermode Andrew Jones
2023-09-04 17:02 ` [PATCH v3 1/6] RISC-V: Make zicbom/zicboz errors consistent Andrew Jones
2023-09-04 17:02 ` [PATCH v3 2/6] RISC-V: Enable cbo.zero in usermode Andrew Jones
2023-09-04 17:02 ` [PATCH v3 3/6] RISC-V: hwprobe: Expose Zicboz extension and its block size Andrew Jones
2023-09-04 17:02 ` [PATCH v3 4/6] RISC-V: selftests: Statically link hwprobe test Andrew Jones
2023-09-04 17:02 ` [PATCH v3 5/6] RISC-V: selftests: Convert hwprobe test to kselftest API Andrew Jones
2023-09-04 17:02 ` [PATCH v3 6/6] RISC-V: selftests: Add CBO tests Andrew Jones
2023-09-05 14:36   ` Wang, Xiao W
2023-09-05 16:10     ` Andrew Jones
2023-09-05 20:18       ` Andrew Jones
2023-09-18 10:41   ` Andrew Jones [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20230918-062f2e7be4d5dab914648c91@orel \
    --to=ajones@ventanamicro.com \
    --cc=aou@eecs.berkeley.edu \
    --cc=apatel@ventanamicro.com \
    --cc=conor.dooley@microchip.com \
    --cc=evan@rivosinc.com \
    --cc=linux-riscv@lists.infradead.org \
    --cc=palmer@dabbelt.com \
    --cc=paul.walmsley@sifive.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox