From: Kees Cook <keescook@chromium.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Kees Cook <keescook@chromium.org>,
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 Potapenko <glider@google.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Jann Horn <jannh@google.com>,
"Perla, Enrico" <enrico.perla@intel.com>,
kernel-hardening@lists.openwall.com,
linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/5] init_on_alloc: Unpessimize default-on builds
Date: Tue, 24 Mar 2020 13:32:28 -0700 [thread overview]
Message-ID: <20200324203231.64324-3-keescook@chromium.org> (raw)
In-Reply-To: <20200324203231.64324-1-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.
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 059658604dd6..64e911159ffa 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2665,7 +2665,8 @@ 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;
@@ -2674,7 +2675,8 @@ 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();
}
--
2.20.1
next prev parent reply other threads:[~2020-03-24 20:32 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-24 20:32 [PATCH v2 0/5] Optionally randomize kernel stack offset each syscall Kees Cook
2020-03-24 20:32 ` [PATCH v2 1/5] jump_label: Provide CONFIG-driven build state defaults Kees Cook
2020-03-24 22:06 ` Peter Zijlstra
2020-03-24 20:32 ` Kees Cook [this message]
2020-03-26 15:48 ` [PATCH v2 2/5] init_on_alloc: Unpessimize default-on builds Alexander Potapenko
2020-03-24 20:32 ` [PATCH v2 3/5] stack: Optionally randomize kernel stack offset each syscall Kees Cook
2020-03-30 11:25 ` Mark Rutland
2020-03-30 18:18 ` Kees Cook
2020-03-30 18:27 ` Kees Cook
2020-03-24 20:32 ` [PATCH v2 4/5] x86/entry: Enable random_kstack_offset support Kees Cook
2020-03-28 22:26 ` Kees Cook
2020-03-24 20:32 ` [PATCH v2 5/5] arm64: entry: " Kees Cook
2020-03-25 13:21 ` Mark Rutland
2020-03-25 20:22 ` Kees Cook
2020-03-26 11:15 ` Mark Rutland
2020-03-26 16:31 ` Kees Cook
2020-03-30 11:26 ` Mark Rutland
2020-04-20 20:54 ` Will Deacon
2020-04-20 22:34 ` Kees Cook
2020-04-21 7:02 ` Will Deacon
2020-03-24 21:28 ` [PATCH v2 0/5] Optionally randomize kernel stack offset each syscall Jann Horn
2020-03-24 23:07 ` Kees Cook
2020-03-25 12:15 ` Reshetova, Elena
2020-03-25 20:27 ` Kees Cook
2020-03-25 23:20 ` Jann Horn
2020-03-26 17:18 ` Kees Cook
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