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Re: [PATCH 7/7] pc-bios: s390x: Setup io and ext new psws only once
From: |
Christian Borntraeger |
Subject: |
Re: [PATCH 7/7] pc-bios: s390x: Setup io and ext new psws only once |
Date: |
Wed, 15 Jul 2020 15:16:44 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 |
On 15.07.20 15:13, Janosch Frank wrote:
> On 7/15/20 11:40 AM, Janosch Frank wrote:
>> Absolutely no need to set them up every time before we enable our
>> interrupt masks.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>
> So, this one doesn't seem to be a great idea as a kernel loaded to 0x0
> will overwrite the ext/io new PSWs and we'll then try to load a zero PSW
> when an IRQ hits.
>
> We have two options:
> * Add a piece of code that fixes the low core after a kernel has been loaded
> * Leave the code as is and add a comment, so other people don't fall
> into this trap.
>
> I'd be fine with both and for now I'd settle for the second option.
Yes, leave it as is and add a comment.
>
>> ---
>> pc-bios/s390-ccw/start.S | 30 +++++++++++++-----------------
>> 1 file changed, 13 insertions(+), 17 deletions(-)
>>
>> diff --git a/pc-bios/s390-ccw/start.S b/pc-bios/s390-ccw/start.S
>> index 01c4c21b26..0059a15d21 100644
>> --- a/pc-bios/s390-ccw/start.S
>> +++ b/pc-bios/s390-ccw/start.S
>> @@ -34,6 +34,12 @@ loop:
>> remainder:
>> larl %r2,memsetxc
>> ex %r3,0(%r2)
>> + /* Store io new PSW */
>> + larl %r1,io_new_psw
>> + mvc 0x1f0(16),0(%r1)
>> + /* Store ext new PSW */
>> + larl %r1,external_new_psw
>> + mvc 0x1b0(16),0(%r1)
>> done:
>> j main /* And call C */
>>
>> @@ -64,11 +70,6 @@ consume_sclp_int:
>> stctg %c0,%c0,0(%r15)
>> oi 6(%r15),0x2
>> lctlg %c0,%c0,0(%r15)
>> - /* prepare external call handler */
>> - larl %r1, external_new_code
>> - stg %r1, 0x1b8
>> - larl %r1, external_new_mask
>> - mvc 0x1b0(8),0(%r1)
>> /* load enabled wait PSW */
>> larl %r1, enabled_wait_psw
>> lpswe 0(%r1)
>> @@ -81,14 +82,9 @@ consume_sclp_int:
>> .globl consume_io_int
>> consume_io_int:
>> /* enable I/O interrupts in cr6 */
>> - stctg %c6,%c6,0(%r15)
>> - oi 4(%r15), 0xff
>> - lctlg %c6,%c6,0(%r15)
>> - /* prepare i/o call handler */
>> - larl %r1, io_new_code
>> - stg %r1, 0x1f8
>> - larl %r1, io_new_mask
>> - mvc 0x1f0(8),0(%r1)
>> + stctg %c6, %c6, 0(%r15)
>> + oi 4(%r15), 0xff
>> + lctlg %c6, %c6, 0(%r15)
>> /* load enabled wait PSW */
>> larl %r1, enabled_wait_psw
>> lpswe 0(%r1)
>> @@ -112,7 +108,7 @@ disabled_wait_psw:
>> .quad PSW_MASK_DWAIT, 0x0000000000000000
>> enabled_wait_psw:
>> .quad PSW_MASK_EWAIT, 0x0000000000000000
>> -external_new_mask:
>> - .quad PSW_MASK_64
>> -io_new_mask:
>> - .quad PSW_MASK_64
>> +external_new_psw:
>> + .quad PSW_MASK_64, external_new_code
>> +io_new_psw:
>> + .quad PSW_MASK_64, io_new_code
>>
>
>
- Re: [PATCH 1/7] pc-bios: s390x: Fix bootmap.c zipl component entry data handling, (continued)
- [PATCH 6/7] pc-bios: s390x: Use PSW constants in start.S, Janosch Frank, 2020/07/15
- [PATCH 7/7] pc-bios: s390x: Setup io and ext new psws only once, Janosch Frank, 2020/07/15
- Re: [PATCH 7/7] pc-bios: s390x: Setup io and ext new psws only once, Janosch Frank, 2020/07/15
- Re: [PATCH 7/7] pc-bios: s390x: Setup io and ext new psws only once,
Christian Borntraeger <=
- [PATCH] pc-bios: s390x: Add a comment to the io and external new PSW setup, Janosch Frank, 2020/07/15
- Re: [PATCH] pc-bios: s390x: Add a comment to the io and external new PSW setup, Thomas Huth, 2020/07/21
- Re: [PATCH] pc-bios: s390x: Add a comment to the io and external new PSW setup, Christian Borntraeger, 2020/07/22
- Re: [PATCH] pc-bios: s390x: Add a comment to the io and external new PSW setup, Janosch Frank, 2020/07/22
- Re: [PATCH] pc-bios: s390x: Add a comment to the io and external new PSW setup, Christian Borntraeger, 2020/07/22
- Re: [PATCH] pc-bios: s390x: Add a comment to the io and external new PSW setup, Janosch Frank, 2020/07/22
[PATCH 5/7] pc-bios: s390x: Replace lowcore offsets with pointers in dasd-ipl.c, Janosch Frank, 2020/07/15
[PATCH 4/7] pc-bios: s390x: Rework data initialization, Janosch Frank, 2020/07/15