Re: [kvm-unit-tests PATCH] s390x: Add diag308 subcode 0 testing

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 23.08.19 13:33, Janosch Frank wrote:
> On 8/23/19 1:00 PM, David Hildenbrand wrote:
>> On 22.08.19 13:11, Janosch Frank wrote:
>>> By adding a load reset routine to cstart.S we can also test the clear
>>> reset done by subcode 0, as we now can restore our registers again.
>>>
>>> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
>>> ---
>>> I managed to extract this from another bigger test, so let's add it to the bunch.
>>> I'd be very happy about assembly review :-)
>>> ---
>>>  s390x/cstart64.S | 27 +++++++++++++++++++++++++++
>>>  s390x/diag308.c  | 31 ++++++++++---------------------
>>>  2 files changed, 37 insertions(+), 21 deletions(-)
>>>
>>> diff --git a/s390x/cstart64.S b/s390x/cstart64.S
>>> index dedfe80..47045e1 100644
>>> --- a/s390x/cstart64.S
>>> +++ b/s390x/cstart64.S
>>> @@ -145,6 +145,33 @@ memsetxc:
>>>  	.endm
>>>  
>>>  .section .text
>>> +/*
>>> + * load_reset calling convention:
>>> + * %r2 subcode (0 or 1)
>>> + */
>>> +.globl load_reset
>>> +load_reset:
>>> +	SAVE_REGS
>>> +	/* Save the first PSW word to the IPL PSW */
>>> +	epsw	%r0, %r1
>>> +	st	%r0, 0
>>> +	/* Store the address and the bit for 31 bit addressing */
>>> +	larl    %r0, 0f
>>> +	oilh    %r0, 0x8000
>>> +	st      %r0, 0x4
>>> +	/* Do the reset */
>>> +	diag    %r0,%r2,0x308
>>> +	/* Failure path */
>>> +	xgr	%r2, %r2
>>> +	br	%r14
>>> +	/* Success path */
>>> +	/* We lost cr0 due to the reset */
>>> +0:	larl	%r1, initial_cr0
>>> +	lctlg	%c0, %c0, 0(%r1)
>>> +	RESTORE_REGS
>>> +	lhi	%r2, 1
>>> +	br	%r14
>>> +
>>>  pgm_int:
>>>  	SAVE_REGS
>>>  	brasl	%r14, handle_pgm_int
>>> diff --git a/s390x/diag308.c b/s390x/diag308.c
>>> index f085b1a..baf9fd3 100644
>>> --- a/s390x/diag308.c
>>> +++ b/s390x/diag308.c
>>> @@ -21,32 +21,20 @@ static void test_priv(void)
>>>  	check_pgm_int_code(PGM_INT_CODE_PRIVILEGED_OPERATION);
>>>  }
>>>  
>>> +
>>>  /*
>>> - * Check that diag308 with subcode 1 loads the PSW at address 0, i.e.
>>> + * Check that diag308 with subcode 0 and 1 loads the PSW at address 0, i.e.
>>>   * that we can put a pointer into address 4 which then gets executed.
>>>   */
>>> +extern int load_reset(u64);
>>> +static void test_subcode0(void)
>>> +{
>>> +	report("load modified clear done", load_reset(0));
>>> +}
>>> +
>>>  static void test_subcode1(void)
>>>  {
>>> -	uint64_t saved_psw = *(uint64_t *)0;
>>> -	long subcode = 1;
>>> -	long ret, tmp;
>>> -
>>> -	asm volatile (
>>> -		"	epsw	%0,%1\n"
>>> -		"	st	%0,0\n"
>>> -		"	larl	%0,0f\n"
>>> -		"	oilh	%0,0x8000\n"
>>> -		"	st	%0,4\n"
>>> -		"	diag	0,%2,0x308\n"
>>> -		"	lghi	%0,0\n"
>>> -		"	j	1f\n"
>>> -		"0:	lghi	%0,1\n"
>>> -		"1:"
>>> -		: "=&d"(ret), "=&d"(tmp) : "d"(subcode) : "memory");
>>> -
>>> -	*(uint64_t *)0 = saved_psw;
>>> -
>>> -	report("load normal reset done", ret == 1);
>>> +	report("load normal reset done", load_reset(1));
>>>  }
>>>  
>>>  /* Expect a specification exception when using an uneven register */
>>> @@ -107,6 +95,7 @@ static struct {
>>>  	void (*func)(void);
>>>  } tests[] = {
>>>  	{ "privileged", test_priv },
>>> +	{ "subcode 0", test_subcode0 },
>>>  	{ "subcode 1", test_subcode1 },
>>>  	{ "subcode 5", test_subcode5 },
>>>  	{ "subcode 6", test_subcode6 },
>>>
>>
>> So, in general I am wondering if we should restore the original IPL_PSW
>> after we used it - is there any chance we might require the old value
>> again (I guess we're fine with cpu resets)?
> 
> I currently don't see a need, but we could cache it in the restart old
> psw address. Or we just store back the two word constant.
> 

If there's no need right no, I guess we can skip that. Was just wondering.


-- 

Thanks,

David / dhildenb



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Kernel Development]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite Info]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Linux Media]     [Device Mapper]

  Powered by Linux