From: Richard Henderson <richard.henderson@linaro.org>
To: Peter Maydell <peter.maydell@linaro.org>, qemu-devel@nongnu.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Richard Henderson <rth@twiddle.net>,
patches@linaro.org
Subject: Re: [Qemu-devel] [PATCH 2/3] exec.c: Don't accidentally sign-extend 4-byte loads in subpage_read()
Date: Tue, 12 Jun 2018 10:58:26 -1000 [thread overview]
Message-ID: <c804c5dd-aa13-982e-df73-f18e3b010aa6@linaro.org> (raw)
In-Reply-To: <20180611171007.4165-3-peter.maydell@linaro.org>
On 06/11/2018 07:10 AM, Peter Maydell wrote:
> In subpage_read() we perform a load of the data into a local buffer
> which we then access using ldub_p(), lduw_p(), ldl_p() or ldq_p()
> depending on its size, storing the result into the uint64_t *data.
> Since ldl_p() returns an 'int', this means that for the 4-byte
> case we will sign-extend the data, whereas for 1 and 2 byte
> reads we zero-extend it.
>
> This ought not to matter since the caller will likely ignore values in
> the high bytes of the data, but add a cast so that we're consistent.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
r~
next prev parent reply other threads:[~2018-06-12 20:58 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-11 17:10 [Qemu-devel] [PATCH 0/3] Add ldn_*_p() and stn_*_p() and use them in exec.c Peter Maydell
2018-06-11 17:10 ` [Qemu-devel] [PATCH 1/3] bswap: Add new stn_*_p() and ldn_*_p() memory access functions Peter Maydell
2018-06-11 17:43 ` Philippe Mathieu-Daudé
2018-06-11 17:51 ` Peter Maydell
2018-06-11 17:52 ` Peter Maydell
2018-06-12 21:04 ` Richard Henderson
2018-06-11 17:10 ` [Qemu-devel] [PATCH 2/3] exec.c: Don't accidentally sign-extend 4-byte loads in subpage_read() Peter Maydell
2018-06-12 20:58 ` Richard Henderson [this message]
2018-06-11 17:10 ` [Qemu-devel] [PATCH 3/3] exec.c: Use stn_p() and ldn_p() instead of explicit switches Peter Maydell
2018-06-11 17:43 ` Philippe Mathieu-Daudé
2018-06-12 20:58 ` Richard Henderson
2018-06-11 17:40 ` [Qemu-devel] [PATCH 0/3] Add ldn_*_p() and stn_*_p() and use them in exec.c no-reply
2018-06-11 19:00 ` no-reply
2018-06-15 10:17 ` Peter Maydell
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