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From: Richard Henderson <richard.henderson@linaro.org>
To: David Hildenbrand <david@redhat.com>, qemu-devel@nongnu.org
Cc: qemu-s390x@nongnu.org
Subject: Re: [PATCH v3 14/18] target/s390x: Rely on unwinding in s390_cpu_tlb_fill
Date: Fri, 27 Sep 2019 09:16:12 -0700	[thread overview]
Message-ID: <fb1096e8-1b3d-ff46-97c5-c03e8f838e34@linaro.org> (raw)
In-Reply-To: <f3277035-17b8-59a6-e4ae-7b1a95ea0c84@redhat.com>

On 9/27/19 4:02 AM, David Hildenbrand wrote:
> On 26.09.19 18:26, Richard Henderson wrote:
>> We currently set ilen to AUTO, then overwrite that during
>> unwinding, then overwrite that for the code access case.
>>
>> This can be simplified to setting ilen to our arbitrary
>> value for the (undefined) code access case, then rely on
>> unwinding to overwrite that with the correct value for
>> the data access case.
>>
>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>>  target/s390x/excp_helper.c | 23 +++++++----------------
>>  1 file changed, 7 insertions(+), 16 deletions(-)
>>
>> diff --git a/target/s390x/excp_helper.c b/target/s390x/excp_helper.c
>> index 98a1ee8317..8ce992e639 100644
>> --- a/target/s390x/excp_helper.c
>> +++ b/target/s390x/excp_helper.c
>> @@ -96,7 +96,7 @@ bool s390_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
>>  {
>>      S390CPU *cpu = S390_CPU(cs);
>>  
>> -    trigger_pgm_exception(&cpu->env, PGM_ADDRESSING, ILEN_AUTO);
>> +    trigger_pgm_exception(&cpu->env, PGM_ADDRESSING, ILEN_UNWIND);
> 
> Hmm, we always trigger a pgm exceptions, meaning we set
> cs->exception_index even if we have probe = true. Confused by that.

This is the CONFIG_USER_ONLY version, for which probe is always false.  Perhaps
I shouldn't have made the function interface identical, but it did appear to
make things cleaner for most targets.

>> +    trigger_pgm_exception(env, excp, 2);
> 
> I wonder if it is still worth setting this only conditionally. Most
> probably not.

I don't see that it would be.  I hope the comment is clear about this arbitrary
value is overwritten during unwinding.


r~


  reply	other threads:[~2019-09-27 17:45 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-26 16:25 [PATCH v3 00/18] target/s390: Use tcg unwinding for ilen Richard Henderson
2019-09-26 16:25 ` [PATCH v3 01/18] target/s390x: Truncate 32-bit psw_addr before creating TB Richard Henderson
2019-09-27 10:23   ` David Hildenbrand
2019-09-27 18:24     ` Richard Henderson
2019-09-26 16:25 ` [PATCH v3 02/18] target/s390x: Add ilen to unwind data Richard Henderson
2019-09-27 10:30   ` David Hildenbrand
2019-09-27 16:02     ` Richard Henderson
2019-09-30  7:55       ` David Hildenbrand
2019-09-30 15:03         ` Richard Henderson
2019-09-30 15:42           ` David Hildenbrand
2019-09-30 16:15             ` Richard Henderson
2019-09-30 17:13               ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 03/18] target/s390x: Remove ilen parameter from tcg_s390_program_interrupt Richard Henderson
2019-09-27 10:31   ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 04/18] target/s390x: Remove ilen parameter from s390_program_interrupt Richard Henderson
2019-09-27 10:34   ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 05/18] target/s390x: Use tcg_s390_program_interrupt in TCG helpers Richard Henderson
2019-09-27 10:40   ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 06/18] target/s390x: Push trigger_pgm_exception lower in s390_cpu_tlb_fill Richard Henderson
2019-09-27 10:41   ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 07/18] target/s390x: Handle tec " Richard Henderson
2019-09-27 10:42   ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 08/18] target/s390: Return exception from mmu_translate_real Richard Henderson
2019-09-27 10:44   ` David Hildenbrand
2019-09-27 12:47     ` David Hildenbrand
2019-09-27 16:08     ` Richard Henderson
2019-09-26 16:26 ` [PATCH v3 09/18] target/s390x: Remove exc argument to mmu_translate_asce Richard Henderson
2019-09-27 10:45   ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 10/18] target/s390: Return exception from mmu_translate Richard Henderson
2019-09-27 10:55   ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 11/18] target/s390: Return exception from translate_pages Richard Henderson
2019-09-27 10:56   ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 12/18] target/s390x: Remove fail variable from s390_cpu_tlb_fill Richard Henderson
2019-09-27 10:56   ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 13/18] target/s390x: Simplify helper_lra Richard Henderson
2019-09-27 10:57   ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 14/18] target/s390x: Rely on unwinding in s390_cpu_tlb_fill Richard Henderson
2019-09-27 11:02   ` David Hildenbrand
2019-09-27 16:16     ` Richard Henderson [this message]
2019-09-30  7:56       ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 15/18] target/s390x: Rely on unwinding in s390_cpu_virt_mem_rw Richard Henderson
2019-09-27 11:04   ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 16/18] target/s390x: Remove ILEN_AUTO Richard Henderson
2019-09-27 11:04   ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 17/18] target/s390x: Remove ilen argument from trigger_access_exception Richard Henderson
2019-09-27 11:04   ` David Hildenbrand
2019-09-26 16:26 ` [PATCH v3 18/18] target/s390x: Remove ilen argument from trigger_pgm_exception Richard Henderson
2019-09-27 11:05   ` David Hildenbrand
2019-09-27  8:18 ` [PATCH v3 00/18] target/s390: Use tcg unwinding for ilen David Hildenbrand

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