From: Jarkko Sakkinen <jarkko@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Yu, Yu-cheng" <yu-cheng.yu@intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-api@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Andy Lutomirski <luto@kernel.org>,
Balbir Singh <bsingharora@gmail.com>,
Borislav Petkov <bp@alien8.de>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Eugene Syromiatnikov <esyr@redhat.com>,
Florian Weimer <fweimer@redhat.com>,
"H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Kees Cook <keescook@chromium.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Nadav Amit <nadav.amit@gmail.com>,
Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
Randy Dunlap <rdunlap@infradead.org>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
Dave Martin <Dave.Martin@arm.com>,
Weijiang Yang <weijiang.yang@intel.com>,
Pengfei Xu <pengfei.xu@intel.com>,
Haitao Huang <haitao.huang@intel.com>
Subject: Re: [PATCH v22 8/8] x86/vdso: Add ENDBR64 to __vdso_sgx_enter_enclave
Date: Fri, 12 Mar 2021 18:56:45 +0200 [thread overview]
Message-ID: <YEudTW1cKAQG10BG@kernel.org> (raw)
In-Reply-To: <YEnX3Zn0FXPt7pcM@hirez.programming.kicks-ass.net>
On Thu, Mar 11, 2021 at 09:42:05AM +0100, Peter Zijlstra wrote:
> On Thu, Mar 11, 2021 at 05:36:06AM +0200, Jarkko Sakkinen wrote:
> > Does it do any harm to put it there unconditionally?
>
> Blows up your text footprint and I$ pressure. These instructions are 4
> bytes each.
>
> Aside from that, they're a NOP, so only consume front-end resources
> (hopefully) on older CPUs and when IBT is disabled.
OK, understood, thanks for the explanation.
/Jarkko
prev parent reply other threads:[~2021-03-12 16:57 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-10 22:05 [PATCH v22 0/8] Control-flow Enforcement: Indirect Branch Tracking Yu-cheng Yu
2021-03-10 22:05 ` [PATCH v22 1/8] x86/cet/ibt: Update Kconfig for user-mode " Yu-cheng Yu
2021-03-10 22:05 ` [PATCH v22 2/8] x86/cet/ibt: User-mode Indirect Branch Tracking support Yu-cheng Yu
2021-03-10 22:05 ` [PATCH v22 3/8] x86/cet/ibt: Handle signals for Indirect Branch Tracking Yu-cheng Yu
2021-03-10 22:05 ` [PATCH v22 4/8] x86/cet/ibt: Update ELF header parsing " Yu-cheng Yu
2021-03-10 22:05 ` [PATCH v22 5/8] x86/cet/ibt: Update arch_prctl functions " Yu-cheng Yu
2021-03-10 22:05 ` [PATCH v22 6/8] x86/vdso/32: Add ENDBR32 to __kernel_vsyscall entry point Yu-cheng Yu
2021-03-10 22:05 ` [PATCH v22 7/8] x86/vdso: Insert endbr32/endbr64 to vDSO Yu-cheng Yu
2021-03-10 22:05 ` [PATCH v22 8/8] x86/vdso: Add ENDBR64 to __vdso_sgx_enter_enclave Yu-cheng Yu
2021-03-10 22:39 ` Jarkko Sakkinen
2021-03-10 22:55 ` Yu, Yu-cheng
2021-03-10 23:17 ` Borislav Petkov
2021-03-10 23:20 ` Dave Hansen
2021-03-10 23:22 ` Yu, Yu-cheng
2021-03-12 16:55 ` Jarkko Sakkinen
2021-03-12 16:57 ` Jarkko Sakkinen
2021-03-12 16:59 ` Dave Hansen
2021-03-11 3:36 ` Jarkko Sakkinen
2021-03-11 8:42 ` Peter Zijlstra
2021-03-11 15:44 ` Yu, Yu-cheng
2021-03-12 16:56 ` Jarkko Sakkinen [this message]
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