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From: Alex =?utf-8?Q?Benn=C3=A9e?= <alex.bennee@linaro.org>
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Date: Wed, 20 Apr 2016 14:14:20 +0100
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Subject: Re: [Qemu-devel] [PATCH 03/11] tci: Make direct jump patching
 thread-safe
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To: Sergey Fedorov <serge.fdrv@gmail.com>
Cc: Sergey Fedorov <sergey.fedorov@linaro.org>, qemu-devel@nongnu.org, Paolo Bonzini <pbonzini@redhat.com>, Peter Crosthwaite <crosthwaite.peter@gmail.com>, Richard Henderson <rth@twiddle.net>, Stefan Weil <sw@weilnetz.de>


Sergey Fedorov <serge.fdrv@gmail.com> writes:

> On 20/04/16 12:42, Alex Bennée wrote:
>> Sergey Fedorov <sergey.fedorov@linaro.org> writes:
>>> diff --git a/tcg/tci/tcg-target.inc.c b/tcg/tci/tcg-target.inc.c
>>> index 4afe4d7a8d59..7e6180e62898 100644
>>> --- a/tcg/tci/tcg-target.inc.c
>>> +++ b/tcg/tci/tcg-target.inc.c
>>> @@ -556,6 +556,8 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, const TCGArg *args,
>>>          if (s->tb_jmp_offset) {
>>>              /* Direct jump method. */
>>>              assert(args[0] < ARRAY_SIZE(s->tb_jmp_offset));
>>> +            /* Align for atomic patching and thread safety */
>>> +            s->code_ptr = (uint8_t *)(((uintptr_t)s->code_ptr + 3) &
>>> ~3);
>> Seeing this pattern is being used over and over again I wonder if we
>> should have some utility helper functions for this? Perhaps we should
>> steal the kernels ALIGN macros?
>
> Good point, really. I see such a macro in hw/display/qxl.c and
> kvm-all.c. It'd be better a common definition. Any idea of where to
> put it?

Somewhere inside include/qemu. osdep.h has ROUND_UP/DOWN functions maybe
there makes the most sense?
>
> Kind regards,
> Sergey


--
Alex Bennée