Re: [RFC] Testing 7.1.0-rc2, qemu-ppc does not give valid disassembly

["Cédric Le Goater" <clg@kaod.org>]

Hello Pierre,

On 8/11/22 15:31, Pierre Muller wrote:
>    Hello,
> 
>    I don't know if this is the right place to submit this report,

Here is a good place :

    https://gitlab.com/qemu-project/qemu/-/issues/

> but I have a problem with my attempt to check the 7.1.0 release candidate
> for linux user powerpc CPU.
> 
>    I am testing a simple executable, compiled with Free Pacal compiler,
> but also linked to libc.
> 
> This is what I obtain with the new rc:
> 
> ~/gnu/qemu/build-qemu-7.1.0-rc1/qemu-ppc -L ~/sys-root/powerpc-linux -d in_asm tprintf
> ----------------
> IN: _start
> 0x3ffda784:
> OBJD-T: 7c230b78388000003821fff0908100004bfe756d
> 
> ----------------
> IN: _dl_start
> 0x3ffc1d00:
> OBJD-T: 9421fd407c0802a6429f0005
> 
> ----------------
> IN: _dl_start
> 0x3ffc1d0c:
> OBJD-T: 93c102b8938102b092e1029c930102a07fc802a6932102a4934102a8936102ac
> OBJD-T: 900102c493a102b493e102bc7c7c1b783fde00043bded2d07d4d42a67d2c42a6
> OBJD-T: 7d0d42a67c0a40004082fff0
> 
> ----------------
> IN: _dl_start
> 0x3ffc1d58:
> OBJD-T: 9141026838e00013f00004d7
> 
> With qemu-ppc version 7.0.0, I get this:
> ----------------
> IN: _start
> 0x3ffda784:  7c230b78  mr       r3, r1
> 0x3ffda788:  38800000  li       r4, 0
> 0x3ffda78c:  3821fff0  addi     r1, r1, -0x10
> 0x3ffda790:  90810000  stw      r4, 0(r1)
> 0x3ffda794:  4bfe756d  bl       0x3ffc1d00
> 
> ----------------
> IN: _dl_start
> 0x3ffc1d00:  9421fd40  stwu     r1, -0x2c0(r1)
> 0x3ffc1d04:  7c0802a6  mflr     r0
> 0x3ffc1d08:  429f0005  bdnzl    0x3ffc1d0c
> 
> Which is way better!
> 
>    I did find that this is related to the fact that
> upon configuration, meson finds no capstone library,
> while disassembly of powerpc CPU has been moved to use of
> capstone in this commit:
> 
> 
> commit 333f944c15e7a6f5503f92d80529a368519d6638
> Author: Thomas Huth <thuth@redhat.com>
> Date:   Thu May 5 19:36:19 2022 +0200
> 
>       disas: Remove old libopcode ppc disassembler
> 
>       Capstone should be superior to the old libopcode disassembler,
>       so we can drop the old file nowadays.
> 
>       Message-Id: <20220505173619.488350-1-thuth@redhat.com>
>       Reviewed-by: Cédric Le Goater <clg@kaod.org>
>       Signed-off-by: Thomas Huth <thuth@redhat.com>
> 
> 
> Even when trying to compile the git checkout,
> which contains capstone as a sub-module, in capstone sub-directory,
> I always get capstone support set to NO by meson configuration.
> 
> configure --help says:
> 
> 155:  capstone        Whether and how to find the capstone library
> 
>    Is there a way to tell configure to use the submodule?
> Why doesn't it use the sub-module if pkg-config says that there
> is not system capstone library installed?

Did you try --enable-capstone ?

See :

    https://lore.kernel.org/qemu-devel/4986d31e-00b3-bb94-654d-9659af8ae09f@linaro.org/

Thanks,

C.