On 8/1/2025 2:53 PM, Heiko Carstens wrote:
> On Thu, Jul 10, 2025 at 06:35:17PM +0200, Jens Remus wrote:
>> +static inline void __s390_get_dwarf_fpr(unsigned long *val, int regnum)
>> +{
>> + switch (regnum) {
>> + case 16:
>> + fpu_std(0, (freg_t *)val);
>> + break;
>
> ...
>
>> +static inline int s390_unwind_user_get_reg(unsigned long *val, int regnum)
>> +{
>> + if (0 <= regnum && regnum <= 15) {
>> + struct pt_regs *regs = task_pt_regs(current);
>> + *val = regs->gprs[regnum];
>> + } else if (16 <= regnum && regnum <= 31) {
>> + __s390_get_dwarf_fpr(val, regnum);
>
> This won't work with other potential in-kernel fpu users. User space fpr
> contents may have been written to the current task's fpu save area and fprs
> may have been clobbered by in-kernel users; so you need to get register
> contents from the correct location. See arch/s390/include/asm/fpu.h.
Thanks! Will implement all the review feedback and send a RFC V2 once I
am back from vacation. Will be away from keyboard for a few weeks.
Regards,
Jens
--
Jens Remus
Linux on Z Development (D3303)
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jre...@de.ibm.com
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