Re: [PATCH v1 2/4] s390x: Define the PSW bits

[Janosch Frank <frankja@linux.ibm.com>]

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On 11/14/19 9:40 AM, Pierre Morel wrote:
> 
> On 2019-11-13 17:05, Janosch Frank wrote:
>> On 11/13/19 1:23 PM, Pierre Morel wrote:
>>> Instead of assigning obfuscated masks to the PSW dedicated to the
>>> exceptions, let's define the masks explicitely, it will clarify the
>> s/explicitely/explicitly/
>> Try to break that up into sentences.
> OK thx
>>
>>> usage.
>>>
>>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
>>> ---
>>>   lib/s390x/asm/arch_bits.h | 32 ++++++++++++++++++++++++++++++++
>>>   lib/s390x/asm/arch_def.h  |  6 ++----
>>>   s390x/cstart64.S          | 13 +++++++------
>>>   3 files changed, 41 insertions(+), 10 deletions(-)
>>>   create mode 100644 lib/s390x/asm/arch_bits.h
>>>
>>> diff --git a/lib/s390x/asm/arch_bits.h b/lib/s390x/asm/arch_bits.h
>>> new file mode 100644
>>> index 0000000..0521125
>>> --- /dev/null
>>> +++ b/lib/s390x/asm/arch_bits.h
>>> @@ -0,0 +1,32 @@
>>> +
>>> +/*
>>> + * Copyright (c) 2019 IBM Corp
>>> + *
>>> + * Authors:
>>> + *  Pierre Morel <pmorel@linux.ibm.com>
>>> + *
>>> + * This code is free software; you can redistribute it and/or modify it
>>> + * under the terms of the GNU Library General Public License version 2.
>>> + */
>>> +#ifndef _ASM_S390X_ARCH_BITS_H_
>>> +#define _ASM_S390X_ARCH_BITS_H_
>>> +
>>> +#define PSW_MASK_PER		0x4000000000000000
>>> +#define PSW_MASK_DAT		0x0400000000000000
>>> +#define PSW_MASK_IO		0x0200000000000000
>>> +#define PSW_MASK_EXT		0x0100000000000000
>>> +#define PSW_MASK_BASE		0x0000000000000000
>>> +#define PSW_MASK_KEY		0x00F0000000000000
>>> +#define PSW_MASK_MCHECK		0x0004000000000000
>>> +#define PSW_MASK_WAIT		0x0002000000000000
>>> +#define PSW_MASK_PSTATE		0x0001000000000000
>>> +#define PSW_MASK_ASC		0x0000C00000000000
>>> +#define PSW_MASK_CC		0x0000300000000000
>>> +#define PSW_MASK_PM		0x00000F0000000000
>>> +#define PSW_MASK_RI		0x0000008000000000
>>> +#define PSW_MASK_EA		0x0000000100000000
>>> +#define PSW_MASK_BA		0x0000000080000000
>> a-f should be lower case in hex values.
>> Also, do we need all of them?
>> I'd like to keep it as small as poss
>>
>>
>>>> +
>>>> +#endif
>>>> diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
>>>> index 96cca2e..34c1188 100644
>>>> --- a/lib/s390x/asm/arch_def.h
>>>> +++ b/lib/s390x/asm/arch_def.h
>>>> @@ -10,15 +10,13 @@
>>>>   #ifndef _ASM_S390X_ARCH_DEF_H_
>>>>   #define _ASM_S390X_ARCH_DEF_H_
>>>>   
>>>> +#include <asm/arch_bits.h>
>>>> +
>>>>   struct psw {
>>>>   	uint64_t	mask;
>>>>   	uint64_t	addr;
>>>>   };
>>>>   
>>>> -#define PSW_MASK_EXT			0x0100000000000000UL
>>>> -#define PSW_MASK_DAT			0x0400000000000000UL
>>>> -#define PSW_MASK_PSTATE			0x0001000000000000UL
>>>> -
>>>>   #define CR0_EXTM_SCLP			0X0000000000000200UL
>>>>   #define CR0_EXTM_EXTC			0X0000000000002000UL
>>>>   #define CR0_EXTM_EMGC			0X0000000000004000UL
>>>> diff --git a/s390x/cstart64.S b/s390x/cstart64.S
>>>> index eaff481..7475f32 100644
>>>> --- a/s390x/cstart64.S
>>>> +++ b/s390x/cstart64.S
>>>> @@ -11,6 +11,7 @@
>>>>    * under the terms of the GNU Library General Public License version 2.
>>>>    */
>>>>   #include <asm/asm-offsets.h>
>>>> +#include <asm/arch_bits.h>
>>>>   #include <asm/sigp.h>
>>>>   
>>>>   .section .init
>>>> @@ -196,17 +197,17 @@ svc_int:
>>>>   
>>>>   	.align	8
>>>>   initial_psw:
>>>> -	.quad	0x0000000180000000, clear_bss_start
>>>> +	.quad	PSW_EXCEPTION_MASK, clear_bss_start
>>>>   pgm_int_psw:
>>>> -	.quad	0x0000000180000000, pgm_int
>>>> +	.quad	PSW_EXCEPTION_MASK, pgm_int
>>>>   ext_int_psw:
>>>> -	.quad	0x0000000180000000, ext_int
>>>> +	.quad	PSW_EXCEPTION_MASK, ext_int
>>>>   mcck_int_psw:
>>>> -	.quad	0x0000000180000000, mcck_int
>>>> +	.quad	PSW_EXCEPTION_MASK, mcck_int
>>>>   io_int_psw:
>>>> -	.quad	0x0000000180000000, io_int
>>>> +	.quad	PSW_EXCEPTION_MASK, io_int
>>>>   svc_int_psw:
>>>> -	.quad	0x0000000180000000, svc_int
>>>> +	.quad	PSW_EXCEPTION_MASK, svc_int
>>>>   initial_cr0:
>>>>   	/* enable AFP-register control, so FP regs (+BFP instr) can be used */
>>>>   	.quad	0x0000000000040000
>>>>
>> ible.
> 
> OK
> 
> 
>>
>>> +
>>> +#define PSW_EXCEPTION_MASK (PSW_MASK_EA|PSW_MASK_BA)
>> That's not a bit anymore, shouldn't that be in arch_def.h?
>> Also please add a comment, that this is 64 bit addressing.
> 
> 
> Don't we use the 64bit architecture only?

architecture != addressing
We can do 24 bit addressing on zArch...
We mostly use ESAME (zArch), but old machines start up in the old mode
and then we transition to zArch via a SIGP.

> 
> Regards,
> 
> Pierre
> 
> 



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