From: Ard Biesheuvel <ard.biesheuvel@linaro.org> To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Arnd Bergmann <arnd@arndb.de>, Steven Rostedt <rostedt@goodmis.org>, Peter Zijlstra <peterz@infradead.org> Subject: [PATCH 2/5] kernel/jump_label: implement generic support for relative references Date: Wed, 27 Jun 2018 18:06:01 +0200 [thread overview] Message-ID: <20180627160604.8154-3-ard.biesheuvel@linaro.org> (raw) In-Reply-To: <20180627160604.8154-1-ard.biesheuvel@linaro.org> To reduce the size taken up by absolute references in jump label entries themselves and the associated relocation records in the .init segment, add support for emitting them as 32-bit relative references instead. Note that this requires some extra care in the sorting routine, given that the offsets change when entries are moved around in the jump_entry table. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- arch/Kconfig | 3 +++ include/linux/jump_label.h | 28 ++++++++++++++++++++ kernel/jump_label.c | 20 +++++++++++++- 3 files changed, 50 insertions(+), 1 deletion(-) diff --git a/arch/Kconfig b/arch/Kconfig index 2b8b70820002..22fa3792626e 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -348,6 +348,9 @@ config HAVE_PERF_USER_STACK_DUMP config HAVE_ARCH_JUMP_LABEL bool +config HAVE_ARCH_JUMP_LABEL_RELATIVE + bool + config HAVE_RCU_TABLE_FREE bool diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index 86ec0652d3b1..aa203dffe72c 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -121,6 +121,32 @@ struct static_key { #include <asm/jump_label.h> #ifndef __ASSEMBLY__ +#ifdef CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE + +struct jump_entry { + int code; + int target; + int key; +}; + +static inline unsigned long jump_entry_code(const struct jump_entry *entry) +{ + return (unsigned long)&entry->code + entry->code; +} + +static inline unsigned long jump_entry_target(const struct jump_entry *entry) +{ + return (unsigned long)&entry->target + entry->target; +} + +static inline struct static_key *jump_entry_key(const struct jump_entry *entry) +{ + unsigned long key = (unsigned long)&entry->key + entry->key; + + return (struct static_key *)(key & ~1UL); +} + +#else struct jump_entry; /* defined by the architecture */ @@ -139,6 +165,8 @@ static inline struct static_key *jump_entry_key(const struct jump_entry *entry) return (struct static_key *)((unsigned long)entry->key & ~1UL); } +#endif + static inline bool jump_entry_is_branch(const struct jump_entry *entry) { return (unsigned long)entry->key & 1UL; diff --git a/kernel/jump_label.c b/kernel/jump_label.c index c3524c9b3004..285eff13ecd1 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -49,6 +49,22 @@ static int jump_label_cmp(const void *a, const void *b) return 0; } +static void jump_label_swap(void *a, void *b, int size) +{ + long delta = (unsigned long)a - (unsigned long)b; + struct jump_entry *jea = a; + struct jump_entry *jeb = b; + struct jump_entry tmp = *jea; + + jea->code = jeb->code - delta; + jea->target = jeb->target - delta; + jea->key = jeb->key - delta; + + jeb->code = tmp.code + delta; + jeb->target = tmp.target + delta; + jeb->key = tmp.key + delta; +} + static void jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop) { @@ -56,7 +72,9 @@ jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop) size = (((unsigned long)stop - (unsigned long)start) / sizeof(struct jump_entry)); - sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL); + sort(start, size, sizeof(struct jump_entry), jump_label_cmp, + IS_ENABLED(CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE) ? jump_label_swap + : NULL); } static void jump_label_update(struct static_key *key); -- 2.11.0
WARNING: multiple messages have this Message-ID (diff)
From: ard.biesheuvel@linaro.org (Ard Biesheuvel) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 2/5] kernel/jump_label: implement generic support for relative references Date: Wed, 27 Jun 2018 18:06:01 +0200 [thread overview] Message-ID: <20180627160604.8154-3-ard.biesheuvel@linaro.org> (raw) In-Reply-To: <20180627160604.8154-1-ard.biesheuvel@linaro.org> To reduce the size taken up by absolute references in jump label entries themselves and the associated relocation records in the .init segment, add support for emitting them as 32-bit relative references instead. Note that this requires some extra care in the sorting routine, given that the offsets change when entries are moved around in the jump_entry table. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- arch/Kconfig | 3 +++ include/linux/jump_label.h | 28 ++++++++++++++++++++ kernel/jump_label.c | 20 +++++++++++++- 3 files changed, 50 insertions(+), 1 deletion(-) diff --git a/arch/Kconfig b/arch/Kconfig index 2b8b70820002..22fa3792626e 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -348,6 +348,9 @@ config HAVE_PERF_USER_STACK_DUMP config HAVE_ARCH_JUMP_LABEL bool +config HAVE_ARCH_JUMP_LABEL_RELATIVE + bool + config HAVE_RCU_TABLE_FREE bool diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index 86ec0652d3b1..aa203dffe72c 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -121,6 +121,32 @@ struct static_key { #include <asm/jump_label.h> #ifndef __ASSEMBLY__ +#ifdef CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE + +struct jump_entry { + int code; + int target; + int key; +}; + +static inline unsigned long jump_entry_code(const struct jump_entry *entry) +{ + return (unsigned long)&entry->code + entry->code; +} + +static inline unsigned long jump_entry_target(const struct jump_entry *entry) +{ + return (unsigned long)&entry->target + entry->target; +} + +static inline struct static_key *jump_entry_key(const struct jump_entry *entry) +{ + unsigned long key = (unsigned long)&entry->key + entry->key; + + return (struct static_key *)(key & ~1UL); +} + +#else struct jump_entry; /* defined by the architecture */ @@ -139,6 +165,8 @@ static inline struct static_key *jump_entry_key(const struct jump_entry *entry) return (struct static_key *)((unsigned long)entry->key & ~1UL); } +#endif + static inline bool jump_entry_is_branch(const struct jump_entry *entry) { return (unsigned long)entry->key & 1UL; diff --git a/kernel/jump_label.c b/kernel/jump_label.c index c3524c9b3004..285eff13ecd1 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -49,6 +49,22 @@ static int jump_label_cmp(const void *a, const void *b) return 0; } +static void jump_label_swap(void *a, void *b, int size) +{ + long delta = (unsigned long)a - (unsigned long)b; + struct jump_entry *jea = a; + struct jump_entry *jeb = b; + struct jump_entry tmp = *jea; + + jea->code = jeb->code - delta; + jea->target = jeb->target - delta; + jea->key = jeb->key - delta; + + jeb->code = tmp.code + delta; + jeb->target = tmp.target + delta; + jeb->key = tmp.key + delta; +} + static void jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop) { @@ -56,7 +72,9 @@ jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop) size = (((unsigned long)stop - (unsigned long)start) / sizeof(struct jump_entry)); - sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL); + sort(start, size, sizeof(struct jump_entry), jump_label_cmp, + IS_ENABLED(CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE) ? jump_label_swap + : NULL); } static void jump_label_update(struct static_key *key); -- 2.11.0
next prev parent reply other threads:[~2018-06-27 16:07 UTC|newest] Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-06-27 16:05 [PATCH 0/5] add support for relative references in jump tables Ard Biesheuvel 2018-06-27 16:05 ` Ard Biesheuvel 2018-06-27 16:06 ` [PATCH 1/5] kernel/jump_label: abstract jump_entry member accessors Ard Biesheuvel 2018-06-27 16:06 ` Ard Biesheuvel 2018-06-28 8:40 ` Peter Zijlstra 2018-06-28 8:40 ` Peter Zijlstra 2018-06-27 16:06 ` Ard Biesheuvel [this message] 2018-06-27 16:06 ` [PATCH 2/5] kernel/jump_label: implement generic support for relative references Ard Biesheuvel 2018-06-28 8:50 ` Peter Zijlstra 2018-06-28 8:50 ` Peter Zijlstra 2018-06-28 9:02 ` Ard Biesheuvel 2018-06-28 9:02 ` Ard Biesheuvel 2018-06-28 9:04 ` Ard Biesheuvel 2018-06-28 9:04 ` Ard Biesheuvel 2018-06-28 9:25 ` Peter Zijlstra 2018-06-28 9:25 ` Peter Zijlstra 2018-06-28 9:29 ` Ard Biesheuvel 2018-06-28 9:29 ` Ard Biesheuvel 2018-06-28 9:37 ` Peter Zijlstra 2018-06-28 9:37 ` Peter Zijlstra 2018-06-27 16:06 ` [PATCH 3/5] arm64/kernel: jump_label: switch to " Ard Biesheuvel 2018-06-27 16:06 ` Ard Biesheuvel 2018-06-28 9:17 ` Will Deacon 2018-06-28 9:17 ` Will Deacon 2018-06-27 16:06 ` [PATCH 4/5] x86: jump_label: switch to jump_entry accessors Ard Biesheuvel 2018-06-27 16:06 ` Ard Biesheuvel 2018-06-28 9:11 ` Peter Zijlstra 2018-06-28 9:11 ` Peter Zijlstra 2018-06-28 9:14 ` Ard Biesheuvel 2018-06-28 9:14 ` Ard Biesheuvel 2018-06-27 16:06 ` [PATCH 5/5] x86/kernel: jump_table: use relative references Ard Biesheuvel 2018-06-27 16:06 ` Ard Biesheuvel 2018-06-28 8:31 ` Peter Zijlstra 2018-06-28 8:31 ` Peter Zijlstra 2018-06-28 8:34 ` Ard Biesheuvel 2018-06-28 8:34 ` Ard Biesheuvel 2018-06-28 9:28 ` Peter Zijlstra 2018-06-28 9:28 ` Peter Zijlstra 2018-07-02 5:14 ` [lkp-robot] [x86/kernel] b1ff47aace: WARNING:at_kernel/jump_label.c:#__jump_label_update kernel test robot 2018-07-02 5:14 ` kernel test robot
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