From: Richard Henderson <rth@twiddle.net>
To: Jincheng Miao <jmiao@redhat.com>, qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, riku.voipio@iki.fi
Subject: Re: [Qemu-devel] [PATCH] linux-user: Fix syscall instruction usermode emulation on X86_64
Date: Fri, 08 Aug 2014 07:09:25 -1000 [thread overview]
Message-ID: <53E50445.7000405@twiddle.net> (raw)
In-Reply-To: <1407470214-10792-1-git-send-email-jmiao@redhat.com>
On 08/07/2014 05:56 PM, Jincheng Miao wrote:
> Currently syscall instruction is buggy on user mode X86_64,
> the EIP is updated after do_syscall(), that is too late for
> clone(). Because clone() will create a thread at the env->EIP
> (the address of syscall insn), and then child thread enters
> do_syscall() again, that is not expected. Sometimes it is tragic.
>
> User mode syscall insn emulation is not used MSR, so the
> action should be same to INT 0x80. INT 0x80 will update EIP in
> do_interrupt(), ditto for syscall() for consistency.
>
> Signed-off-by: Jincheng Miao <jmiao@redhat.com>
> ---
> linux-user/main.c | 1 -
> target-i386/seg_helper.c | 4 ++--
> 2 files changed, 2 insertions(+), 3 deletions(-)
Reviewed-by: Richard Henderson <rth@twiddle.net>
r~
next prev parent reply other threads:[~2014-08-08 17:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-08 3:56 [Qemu-devel] [PATCH] linux-user: Fix syscall instruction usermode emulation on X86_64 Jincheng Miao
2014-08-08 17:09 ` Richard Henderson [this message]
2014-08-12 7:22 ` Riku Voipio
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