From: "tip-bot2 for Kees Cook" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>,
Thomas Gleixner <tglx@linutronix.de>,
Alexander Potapenko <glider@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: x86/entry] init_on_alloc: Optimize static branches
Date: Thu, 08 Apr 2021 12:13:41 -0000 [thread overview]
Message-ID: <161788402167.29796.5452552471704996304.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210401232347.2791257-3-keescook@chromium.org>
The following commit has been merged into the x86/entry branch of tip:
Commit-ID: 51cba1ebc60df9c4ce034a9f5441169c0d0956c0
Gitweb: https://git.kernel.org/tip/51cba1ebc60df9c4ce034a9f5441169c0d0956c0
Author: Kees Cook <keescook@chromium.org>
AuthorDate: Thu, 01 Apr 2021 16:23:43 -07:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 08 Apr 2021 14:05:19 +02:00
init_on_alloc: Optimize static branches
The state of CONFIG_INIT_ON_ALLOC_DEFAULT_ON (and ...ON_FREE...) did not
change the assembly ordering of the static branches: they were always out
of line. Use the new jump_label macros to check the CONFIG settings to
default to the "expected" state, which slightly optimizes the resulting
assembly code.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexander Potapenko <glider@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Link: https://lore.kernel.org/r/20210401232347.2791257-3-keescook@chromium.org
---
include/linux/mm.h | 10 ++++++----
mm/page_alloc.c | 4 ++--
mm/slab.h | 6 ++++--
3 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8ba4342..616dcaf 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2904,18 +2904,20 @@ static inline void kernel_poison_pages(struct page *page, int numpages) { }
static inline void kernel_unpoison_pages(struct page *page, int numpages) { }
#endif
-DECLARE_STATIC_KEY_FALSE(init_on_alloc);
+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))
return true;
return flags & __GFP_ZERO;
}
-DECLARE_STATIC_KEY_FALSE(init_on_free);
+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);
}
extern bool _debug_pagealloc_enabled_early;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index cfc7287..e2f19bf 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -167,10 +167,10 @@ unsigned long totalcma_pages __read_mostly;
int percpu_pagelist_fraction;
gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
-DEFINE_STATIC_KEY_FALSE(init_on_alloc);
+DEFINE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, init_on_alloc);
EXPORT_SYMBOL(init_on_alloc);
-DEFINE_STATIC_KEY_FALSE(init_on_free);
+DEFINE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_FREE_DEFAULT_ON, init_on_free);
EXPORT_SYMBOL(init_on_free);
static bool _init_on_alloc_enabled_early __read_mostly
diff --git a/mm/slab.h b/mm/slab.h
index 076582f..774c722 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -601,7 +601,8 @@ static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c)
{
- if (static_branch_unlikely(&init_on_alloc)) {
+ if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON,
+ &init_on_alloc)) {
if (c->ctor)
return false;
if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))
@@ -613,7 +614,8 @@ static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c)
static inline bool slab_want_init_on_free(struct kmem_cache *c)
{
- if (static_branch_unlikely(&init_on_free))
+ if (static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON,
+ &init_on_free))
return !(c->ctor ||
(c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)));
return false;
next prev parent reply other threads:[~2021-04-08 12:13 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-01 23:23 [PATCH v10 0/6] Optionally randomize kernel stack offset each syscall Kees Cook
2021-04-01 23:23 ` [PATCH v10 1/6] jump_label: Provide CONFIG-driven build state defaults Kees Cook
2021-04-08 12:13 ` [tip: x86/entry] " tip-bot2 for Kees Cook
2021-04-01 23:23 ` [PATCH v10 2/6] init_on_alloc: Optimize static branches Kees Cook
2021-04-08 12:13 ` tip-bot2 for Kees Cook [this message]
2021-04-01 23:23 ` [PATCH v10 3/6] stack: Optionally randomize kernel stack offset each syscall Kees Cook
2021-04-07 21:37 ` Will Deacon
2021-04-08 12:13 ` [tip: x86/entry] " tip-bot2 for Kees Cook
2021-04-01 23:23 ` [PATCH v10 4/6] x86/entry: Enable random_kstack_offset support Kees Cook
2021-04-08 12:13 ` [tip: x86/entry] " tip-bot2 for Kees Cook
2021-04-01 23:23 ` [PATCH v10 5/6] arm64: entry: " Kees Cook
2021-04-07 21:35 ` Will Deacon
2021-04-08 12:13 ` [tip: x86/entry] " tip-bot2 for Kees Cook
2021-04-01 23:23 ` [PATCH v10 6/6] lkdtm: Add REPORT_STACK for checking stack offsets Kees Cook
2021-04-08 12:13 ` [tip: x86/entry] " tip-bot2 for Kees Cook
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