Re: port-alpha/60479: alpha fails to save/restore fpu registers on signal delivery

[Jason Thorpe <thorpej%me.com@localhost>]

> On Jul 22, 2026, at 1:55 PM, campbell+netbsd%mumble.net@localhost via gnats <gnats-admin%NetBSD.org@localhost> wrote:
> 
>> Number:         60479
>> Category:       port-alpha
>> Synopsis:       alpha fails to save/restore fpu registers on signal delivery
>> Confidential:   no
>> Severity:       serious
>> Priority:       medium
>> Responsible:    port-alpha-maintainer
>> State:          open
>> Class:          sw-bug
>> Submitter-Id:   net
>> Arrival-Date:   Wed Jul 22 20:55:00 +0000 2026
>> Originator:     Taylor R Campbell
>> Release:        
>> Organization:
> The AlphaBSD Fpundation, Inc.
>> Environment:
>> Description:
> 
> FPU registers are not saved and restored on signal delivery,
> according to tests/kernel/t_signal_and_fpu:
> 
> https://releng.netbsd.org/b5reports/alpha/2026/2026.07.21.22.53.03/test.html#kernel_t_signal_and_fpu_double

I’m begnning to suspect this is a Qemu bug, because on real HW:

[     1.000000] AlphaStation 200 4/233, 233MHz
[     1.000000] 8192 byte page size, 1 processor.
[     1.000000] total memory = 384 MB
[     1.000000] (2000 KB reserved for PROM, 382 MB used by NetBSD)
[     1.000000] avail memory = 362 MB
[     1.000000] timecounter: Timecounters tick every 0.976 msec
[     1.000000] Kernelized RAIDframe activated
[     1.000000] mainbus0 (root)
[     1.000000] cpu0 at mainbus0: ID 0 (primary), 21064A-0 (EV45)

I get this:

avanti:thorpej 16$ atf-run t_signal_and_fpu | atf-report
Tests root: /usr/tests/kernel

t_signal_and_fpu (1/1): 3 test cases
    double: [1.041472s] Passed.
    float: [1.040791s] Passed.
    ldouble: [1.041530s] Passed.
[3.151730s]

Summary for 1 test programs:
    3 passed test cases.
    0 failed test cases.
    0 expected failed test cases.
    0 skipped test cases.
avanti:thorpej 17$ 

-- thorpej