[PATCH v2] hppa: Drop old parisc-specific MADV_* constants

[John David Anglin]

On 2023-02-11 1:37 a.m., Helge Deller wrote:
> On 2/10/23 22:48, Joseph Myers wrote:
>> On Fri, 10 Feb 2023, Helge Deller via Libc-alpha wrote:
>>
>>> -  [Add deprecations, removals and changes affecting compatibility here]
>>> +* In the Linux kernel for the hppa/parisc architecture some of the
>>> +  MADV_XXX constants were changed to have the same values as the other
>>> +  architectures.  New programs compiled with this glibc version and which
>>> +  use the madvise call will require at least Linux kernel version 6.2,
>>> +  alternatively stable kernels from versions 6.1.6, 5.15.87, 5.10.163,
>>> +  5.4.228, 4.19.270 or 4.14.303.
>>
>> Normally we'd be a lot more conservative about kernel version
>> requirements, but if we require a new kernel we'd put it in
>> arch_minimum_kernel in the relevant configure.ac.
>
> Basically, programs compiled with the new MADV values should work even
> on all older kernels since it's just an advise for the kernel which it may
> ignore and for which programs should allow the syscall to fail.
> The only program I've found so far to be more strict is the
> tor-browser, which refuses to start if MADV_WIPEONFORK fails.
> But it's unlikely people will use tor on parisc, and IMHO
> if you care about security you should use a more recent kernel anyway.
>
> That said, I can add arch_minimum_kernel=4.14.303 (or 6.2?) but I don't
> think it's necessary.
I don't think adding a arch_minimum_kernel define would help much. I don't know about
gentoo, but the current Debian kernel for hppa is already past the minimum for the new values.

The biggest risk is for people like me that keep a collection of old kernels around to check
for regressions in behavior.  As long as there is no major breakage with old kernels running
new applications, we can make the switch.

Dave

-- 
John David Anglin  dave.anglin@bell.net