From: Lai Jiangshan <jiangshanlai@gmail.com>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
Lai Jiangshan <jiangshan.ljs@antgroup.com>,
Joerg Roedel <jroedel@suse.de>, Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] x86/sev: Add ENCODE_FRAME_POINTER after stack changed for #VC
Date: Fri, 18 Mar 2022 09:14:09 +0800 [thread overview]
Message-ID: <CAJhGHyC1qPee2QOpgR8B+2Sd+XzfoJD3NL9biFZ5gKE-B9r_rQ@mail.gmail.com> (raw)
In-Reply-To: <20220317221943.6vhoqx3fdv7py6hi@treble>
On Fri, Mar 18, 2022 at 6:19 AM Josh Poimboeuf <jpoimboe@redhat.com> wrote:
>
> On Wed, Mar 16, 2022 at 12:16:12PM +0800, Lai Jiangshan wrote:
> > From: Lai Jiangshan <jiangshan.ljs@antgroup.com>
> >
> > In idtentry_vc(), the real frame is changed after it switches to new
> > stack, ENCODE_FRAME_POINTER should be called in case for unwinder.
> >
> > Cc: Joerg Roedel <jroedel@suse.de>
> > Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> > Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
> > ---
> > arch/x86/entry/entry_64.S | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
> > index e20eabaa56b8..f99f2881ed83 100644
> > --- a/arch/x86/entry/entry_64.S
> > +++ b/arch/x86/entry/entry_64.S
> > @@ -540,6 +540,7 @@ SYM_CODE_START(\asmsym)
> > call vc_switch_off_ist
> > movq %rax, %rsp /* Switch to new stack */
> >
> > + ENCODE_FRAME_POINTER
> > UNWIND_HINT_REGS
> >
> > /* Update pt_regs */
>
> Looks right to me. Any chance you have the ability to test this
> scenario by unwinding from #VC with CONFIG_FRAME_POINTER?
>
I don't have the hardware to test it. Actually, it was you to
inspire me to find this in the conversation of my patchset when
I tried to search all the code of switching of %rsp to see how
ENCODE_FRAME_POINTER and UNWIND_HINT_REGS are used once more.
> --
> Josh
>
next prev parent reply other threads:[~2022-03-18 1:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-16 4:16 [PATCH] x86/sev: Add ENCODE_FRAME_POINTER after stack changed for #VC Lai Jiangshan
2022-03-17 22:19 ` Josh Poimboeuf
2022-03-18 1:14 ` Lai Jiangshan [this message]
2022-03-18 17:03 ` Josh Poimboeuf
2022-04-12 12:24 ` Lai Jiangshan
2022-04-27 8:26 ` Lai Jiangshan
2022-05-13 9:04 ` Lai Jiangshan
2022-05-18 18:44 ` [tip: x86/sev] x86/sev: Annotate stack change in the #VC handler tip-bot2 for Lai Jiangshan
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