From: Denys Vlasenko <dvlasenk@redhat.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>, Oleg Nesterov <oleg@redhat.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Alexei Starovoitov <ast@plumgrid.com>,
Will Drewry <wad@chromium.org>, Kees Cook <keescook@chromium.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] x86: stop using PER_CPU_VAR(kernel_stack)
Date: Mon, 23 Mar 2015 18:10:01 +0100 [thread overview]
Message-ID: <551048E9.6060800@redhat.com> (raw)
In-Reply-To: <20150323101815.35bd61c7@gandalf.local.home>
On 03/23/2015 03:18 PM, Steven Rostedt wrote:
> On Sat, 21 Mar 2015 21:44:37 +0100
> Denys Vlasenko <dvlasenk@redhat.com> wrote:
>
>> Instead of PER_CPU_VAR(kernel_stack), 64-bit code
>> can use PER_CPU_VAR(cpu_tss + TSS_sp0).
>
> The change log here is lacking an answer to "why". It only states what
> it does. What's wrong with using kernel_stack? The change log should
> explicitly state that. I have no idea why this patch is needed.
Sorry. The reason is:
We want to get rid of kernel_stack, since it is redundant:
in 64-bits, PER_CPU_VAR(cpu_tss + TSS_sp0) can be used instead,
in 32-bits, PER_CPU_VAR(cpu_current_top_of_stack) can be used instead.
Patch 2/2 in the same series removes kernel_stack.
next prev parent reply other threads:[~2015-03-23 17:10 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-21 20:44 [PATCH 1/2] x86: stop using PER_CPU_VAR(kernel_stack) Denys Vlasenko
2015-03-21 20:44 ` [PATCH 2/2] x86: remove unused kernel_stack per-cpu variable Denys Vlasenko
2015-03-23 14:18 ` [PATCH 1/2] x86: stop using PER_CPU_VAR(kernel_stack) Steven Rostedt
2015-03-23 17:10 ` Denys Vlasenko [this message]
2015-03-23 17:14 ` Borislav Petkov
2015-03-23 17:28 ` Steven Rostedt
2015-03-23 17:38 ` Denys Vlasenko
2015-03-23 17:45 ` Steven Rostedt
2015-03-23 17:51 ` Denys Vlasenko
2015-03-23 18:27 ` Andy Lutomirski
2015-04-24 15:29 ` Denys Vlasenko
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