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From: Richard Henderson <richard.henderson@linaro.org>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: qemu-arm <qemu-arm@nongnu.org>, QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [PATCH 3/4] target/arm: Take an exception if PC is misaligned
Date: Thu, 19 Aug 2021 06:57:36 -1000	[thread overview]
Message-ID: <b6754a17-7b6a-201d-6c33-7759ea8ea270@linaro.org> (raw)
In-Reply-To: <bb739396-f8d1-a5a8-ab1a-61892d9c84e6@linaro.org>

On 8/19/21 6:50 AM, Richard Henderson wrote:
> On 8/19/21 3:40 AM, Peter Maydell wrote:
>>>       uint32_t insn;
>>>       bool is_16bit;
>>>
>>> -    if (arm_pre_translate_insn(dc)) {
>>> +    if (arm_check_ss_active(dc) || arm_check_kernelpage(dc)) {
>>
>>
>> Is it not possible to get a misaligned PC in the Thumb case ?
> 
> No.  The thumb bit is always removed, leaving all pc aligned mod 2.
> Both BXWritePC and BranchWritePC do this, as do we in gen_bx and store_reg.

Do you think it's worth an assert here to make sure we never miss a case?  I did an audit 
of the exception code and it looks like we mask everything correctly there, but...


r~



  reply	other threads:[~2021-08-19 16:58 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-18  1:00 [PATCH 0/4] target/arm: Fix insn exception priorities Richard Henderson
2021-08-18  1:00 ` [PATCH 1/4] target/arm: Take an exception if PSTATE.IL is set Richard Henderson
2021-08-18  1:00 ` [PATCH 2/4] target/arm: Merge disas_a64_insn into aarch64_tr_translate_insn Richard Henderson
2021-08-19 13:36   ` Peter Maydell
2021-08-18  1:00 ` [PATCH 3/4] target/arm: Take an exception if PC is misaligned Richard Henderson
2021-08-18 16:44   ` Richard Henderson
2021-08-19 13:40   ` Peter Maydell
2021-08-19 16:50     ` Richard Henderson
2021-08-19 16:57       ` Richard Henderson [this message]
2021-08-19 19:24         ` Peter Maydell
2021-08-19 20:34           ` Richard Henderson
2021-08-19 19:18   ` Peter Maydell
2021-08-19 19:46     ` Peter Maydell
2021-08-18  1:00 ` [PATCH 4/4] target/arm: Suppress bp for exceptions with more priority Richard Henderson
2021-08-19 13:48   ` Peter Maydell

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