From: Borislav Petkov <bp@alien8.de>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Brian Gerst <brgerst@gmail.com>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [RFC PATCH] x86: Make sure verify_cpu has a good stack
Date: Thu, 3 Mar 2016 17:29:52 +0100 [thread overview]
Message-ID: <20160303162952.GE24621@pd.tnic> (raw)
In-Reply-To: <395B06E1-314F-4F8A-9C89-57F8E4A61B3D@zytor.com>
On Thu, Mar 03, 2016 at 07:26:06AM -0800, H. Peter Anvin wrote:
> Why -8?
GLOBAL(stack_start)
.quad init_thread_union+THREAD_SIZE-8
^^^
But I don't see why it needed the -8 then. It came with a conglomerate
dump in 2002:
commit af53c7a2c81399b805b6d4eff887401a5e50feef
Author: Andi Kleen <ak@muc.de>
Date: Fri Apr 19 20:23:17 2002 -0700
[PATCH] x86-64 architecture specific sync for 2.5.8
- /* Setup the first kernel stack (this instruction is modified by smpboot) */
- .byte 0x48, 0xb8 /* movq *init_rsp,%rax */
-init_rsp:
- .quad init_thread_union+THREAD_SIZE
- movq %rax, %rsp
...
-
- /* SMP bootup changes this */
+ /* SMP bootup changes these two */
.globl initial_code
initial_code:
.quad x86_64_start_kernel
+ .globl init_rsp
+init_rsp:
+ .quad init_thread_union+THREAD_SIZE-8
+
---
But since we decrement first and then copy to stack ptr when we push, I
don't see why we need the -8.
Do you have a better clue?
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
next prev parent reply other threads:[~2016-03-03 16:30 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-02 11:20 [RFC PATCH] x86: Make sure verify_cpu has a good stack Borislav Petkov
2016-03-02 15:55 ` Mika Penttilä
2016-03-02 16:15 ` Borislav Petkov
2016-03-02 16:38 ` Mika Penttilä
2016-03-02 16:55 ` Borislav Petkov
2016-03-02 17:44 ` Mika Penttilä
2016-03-02 16:22 ` Brian Gerst
2016-03-02 16:25 ` Borislav Petkov
2016-03-02 17:53 ` H. Peter Anvin
2016-03-02 18:15 ` Borislav Petkov
2016-03-02 18:25 ` H. Peter Anvin
2016-03-02 18:39 ` H. Peter Anvin
2016-03-02 19:50 ` Borislav Petkov
2016-03-02 20:46 ` Borislav Petkov
2016-03-02 21:35 ` H. Peter Anvin
2016-03-02 21:46 ` Borislav Petkov
2016-03-02 21:54 ` H. Peter Anvin
2016-03-02 22:09 ` Borislav Petkov
2016-03-02 22:11 ` H. Peter Anvin
2016-03-02 22:28 ` Borislav Petkov
2016-03-02 22:32 ` H. Peter Anvin
2016-03-02 22:40 ` Borislav Petkov
2016-03-03 0:13 ` Yinghai Lu
2016-03-03 1:00 ` Yinghai Lu
2016-03-03 2:50 ` Yinghai Lu
2016-03-03 12:28 ` Borislav Petkov
2016-03-03 15:26 ` H. Peter Anvin
2016-03-03 16:29 ` Borislav Petkov [this message]
2016-03-03 20:22 ` H. Peter Anvin
2016-03-03 20:54 ` Borislav Petkov
2016-03-03 21:22 ` H. Peter Anvin
2016-03-03 21:38 ` Borislav Petkov
2016-03-04 1:18 ` Yinghai Lu
2016-03-04 2:25 ` Yinghai Lu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160303162952.GE24621@pd.tnic \
--to=bp@alien8.de \
--cc=brgerst@gmail.com \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=thomas.lendacky@amd.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox