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Message-ID: <dd659c33-59ed-4a39-a260-aac45cd5b408@linux-m68k.org>
Date: Tue, 2 Apr 2024 17:18:23 +1000
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Subject: Re: [PATCH v2] m68k: Avoid CONFIG_COLDFIRE switch in uapi header
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To: Thomas Huth <thuth@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
 linux-m68k@lists.linux-m68k.org, Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-kernel@vger.kernel.org, Oleg Nesterov <oleg@redhat.com>
References: <20240219160126.510498-1-thuth@redhat.com>
 <6f3b246e-7417-4455-abe4-ca3b42fdda4c@linux-m68k.org>
 <4824192b-5573-4246-a47c-ad6249e2900e@app.fastmail.com>
 <c2832612-9a67-4dc1-a8c2-4cc026b14567@redhat.com>
From: Greg Ungerer <gerg@linux-m68k.org>
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Hi Thomas,

On 23/2/24 18:13, Thomas Huth wrote:
> On 20/02/2024 16.09, Arnd Bergmann wrote:
>> On Tue, Feb 20, 2024, at 15:13, Greg Ungerer wrote:
>>> On 20/2/24 02:01, Thomas Huth wrote:
>>>> We should not use any CONFIG switches in uapi headers since these
>>>> only work during kernel compilation; they are not defined for
>>>> userspace. Fix it by moving the struct pt_regs to the kernel-internal
>>>> header instead - struct pt_regs does not seem to be required for
>>>> the userspace headers on m68k at all.
>>>>
>>>> Suggested-by: Greg Ungerer <gerg@linux-m68k.org>
>>>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>>>> ---
>>>>    v2: Move the struct instead of changing the #ifdef
>>>>
>>>>    See previous discussion here:
>>>>    https://lore.kernel.org/lkml/6e3f2a2e-2430-4b4f-9ead-d9a4d5e42713@linux-m68k.org/
>>>
>>> I am fine with this. FWIW the following architectures do
>>> not define pt_regs in their uapi/ptrace.h header either:
>>> arc, arm64, loongarch, nios2, openrisc, riscv, s390, xtensa
>>> Though quite a few of them have a user_pt_regs instead.
>>>
>>> So for me:
>>>
>>> Acked-by: Greg Ungerer <gerg@linux-m68k.org>
>>>
>>> Geert, Arnd, do you have any thoughts on this?
>>
>> It clearly doesn't change the ABI, so that part is fine.
>>
>> If asm/ptrace.h is included by some userspace tool to
>> get the definition, it might cause a compile-time error
>> that needs a trivial source change.
>>
>> This could be needed for ptrace (gdb, strace) or signal
>> handling and setjmp (libc), though it's more likely that these
>> already have their own copies.
> 
> If we still feel unsure, we should maybe rather go with v1:
> 
>   https://lore.kernel.org/lkml/20231110103120.387517-1-thuth@redhat.com/
> 
> ?

We have not had much movement on this.
So... I am confidant that v2 is good, but lets err on the side of caution first up.
I have applied v1 to the m68knommu git tree, for-next branch.

Thanks
Greg