Re: [Qemu-devel] [PATCH] sh4-linux-user: fix multi-threading regression.

[address@hidden]

On Mon, Mar 26, 2012 at 03:07:18PM +0200, Cedric VINCENT wrote:
> This reverts commit fd4bab10 "target-sh4: optimize exceptions": the
> function cpu_restore_state() isn't expected to be called in user-mode,
> as a consequence it isn't protected from race conditions.  For
> information, syscalls are exceptions on Linux/SH4.
> 
> There were two possible fixes: either "tb_lock" is acquired/released
> around the call to cpu_restore_state() [1] or the commit that
> introduced this regression is reverted [2].

I will submit a new version of this patch where the commit fd4bab10
isn't reverted and the call to cpu_restore_state() is protected by
tb_lock instead.  Actually most of the SH4 FPU helpers may call
cpu_restore_state() indirectly, this is the same problem as with
helper_trapa().

Regards,
Cédric.