linux-kernel - Re: [PATCH v1 0/2] selftests/x86: Skip int80 if not supported

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Message-ID: <e5fa1ad5-afa0-4ba2-a60a-d43a2c6e86e5@zytor.com>
Date: Fri, 23 Jan 2026 17:18:20 -0800
From: "H. Peter Anvin" <hpa@...or.com>
To: Sławomir Rosek <srosek@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
        Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        Shuah Khan <shuah@...nel.org>
Cc: Betty Zhou <bettyzhou@...gle.com>, Wake Liu <wakel@...gle.com>,
        Kazuhiro Inaba <kinaba@...gle.com>, Jeff Xu <jeffxu@...gle.com>,
        Alistair Delva <adelva@...gle.com>, linux-kernel@...r.kernel.org,
        linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v1 0/2] selftests/x86: Skip int80 if not supported

On 2026-01-12 03:23, Sławomir Rosek wrote:
> On Wed, Dec 17, 2025 at 2:59 PM Slawomir Rosek <srosek@...gle.com> wrote:
>>
>> The IA32 Emulation support can be either removed from the kernel,
>> disabled by default or disabled at runtime. Some of x86 selftests
>> are crashing for all of above thus is_32bit_syscall_supported()
>> helper is added to skip int80 syscalls if they are not supported.
>>
>> Slawomir Rosek (2):
>>   selftests/x86/ldt_gdt: Skip int80 if not supported
>>   selftests/x86/ptrace_syscall: Skip int80 if not supported
> 
> Hi all,
> 
> Just a gentle reminder, it would be really great if someone could take
> a look. Thanks in advance.

I think grepping the configuration and cmdline files is definitely not the way
to go.

For a solution that works on existing kernels, trapping SIGSEGV and calling
int $0x80 is probably the best way to probe.

	-hpa