From: Kees Cook <keescook@chromium.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Kees Cook <keescook@chromium.org>,
Alexander Potapenko <glider@google.com>,
Elena Reshetova <elena.reshetova@intel.com>,
x86@kernel.org, Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Popov <alex.popov@linux.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Jann Horn <jannh@google.com>,
kernel-hardening@lists.openwall.com,
linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v4 2/5] init_on_alloc: Unpessimize default-on builds
Date: Mon, 22 Jun 2020 12:31:43 -0700 [thread overview]
Message-ID: <20200622193146.2985288-3-keescook@chromium.org> (raw)
In-Reply-To: <20200622193146.2985288-1-keescook@chromium.org>
Right now, the state of CONFIG_INIT_ON_ALLOC_DEFAULT_ON (and
...ON_FREE...) did not change the assembly ordering of the static branch
tests. Use the new jump_label macro to check CONFIG settings to default
to the "expected" state, unpessimizes the resulting assembly code.
Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
include/linux/mm.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0e6824fd4458..0a05b20870c2 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2892,7 +2892,8 @@ static inline void kernel_poison_pages(struct page *page, int numpages,
DECLARE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, init_on_alloc);
static inline bool want_init_on_alloc(gfp_t flags)
{
- if (static_branch_unlikely(&init_on_alloc) &&
+ if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON,
+ &init_on_alloc) &&
!page_poisoning_enabled())
return true;
return flags & __GFP_ZERO;
@@ -2901,7 +2902,8 @@ static inline bool want_init_on_alloc(gfp_t flags)
DECLARE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_FREE_DEFAULT_ON, init_on_free);
static inline bool want_init_on_free(void)
{
- return static_branch_unlikely(&init_on_free) &&
+ return static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON,
+ &init_on_free) &&
!page_poisoning_enabled();
}
--
2.25.1
next prev parent reply other threads:[~2020-06-22 19:31 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-22 19:31 [PATCH v4 0/5] Optionally randomize kernel stack offset each syscall Kees Cook
2020-06-22 19:31 ` [PATCH v4 1/5] jump_label: Provide CONFIG-driven build state defaults Kees Cook
2020-06-22 19:31 ` Kees Cook [this message]
2020-06-22 19:31 ` [PATCH v4 3/5] stack: Optionally randomize kernel stack offset each syscall Kees Cook
2020-06-22 19:40 ` Randy Dunlap
2020-06-22 21:26 ` Kees Cook
2020-06-22 20:07 ` Jann Horn
2020-06-22 21:30 ` Kees Cook
2020-06-22 21:42 ` Jann Horn
2020-06-22 22:04 ` Kees Cook
2020-06-22 22:56 ` Arvind Sankar
2020-06-22 23:07 ` Kees Cook
2020-06-23 0:05 ` Arvind Sankar
2020-06-23 0:56 ` Kees Cook
2020-06-23 13:42 ` David Laight
2020-06-23 12:38 ` Alexander Popov
2020-06-22 19:31 ` [PATCH v4 4/5] x86/entry: Enable random_kstack_offset support Kees Cook
2020-06-22 19:31 ` [PATCH v4 5/5] arm64: entry: " Kees Cook
2020-06-23 9:40 ` Mark Rutland
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=20200622193146.2985288-3-keescook@chromium.org \
--to=keescook@chromium.org \
--cc=alex.popov@linux.com \
--cc=ard.biesheuvel@linaro.org \
--cc=catalin.marinas@arm.com \
--cc=elena.reshetova@intel.com \
--cc=glider@google.com \
--cc=jannh@google.com \
--cc=kernel-hardening@lists.openwall.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=mark.rutland@arm.com \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=will@kernel.org \
--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;
as well as URLs for NNTP newsgroup(s).