From: Ard Biesheuvel <ard.biesheuvel@linaro.org> To: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, Ard Biesheuvel <ard.biesheuvel@linaro.org>, Arnd Bergmann <arnd@arndb.de>, Heiko Carstens <heiko.carstens@de.ibm.com>, Kees Cook <keescook@chromium.org>, Will Deacon <will.deacon@arm.com>, Thomas Gleixner <tglx@linutronix.de>, Catalin Marinas <catalin.marinas@arm.com>, Ingo Molnar <mingo@redhat.com>, Steven Rostedt <rostedt@goodmis.org>, Martin Schwidefsky <schwidefsky@de.ibm.com>, Jessica Yu <jeyu@kernel.org>, Peter Zijlstra <peterz@infradead.org> Subject: [PATCH v3 2/9] kernel/jump_label: implement generic support for relative references Date: Tue, 18 Sep 2018 23:51:37 -0700 [thread overview] Message-ID: <20180919065144.25010-3-ard.biesheuvel@linaro.org> (raw) In-Reply-To: <20180919065144.25010-1-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 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 | 22 ++++++++++++++- 3 files changed, 52 insertions(+), 1 deletion(-) diff --git a/arch/Kconfig b/arch/Kconfig index 6801123932a5..9d329608913e 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -359,6 +359,9 @@ 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 2eadff9b3b90..2768a925bafa 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 { + s32 code; + s32 target; + long key; // key may be far away from the core kernel under KASLR +}; + +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) +{ + long offset = entry->key & ~1L; + + return (struct static_key *)((unsigned long)&entry->key + offset); +} + +#else static inline unsigned long jump_entry_code(const struct jump_entry *entry) { @@ -137,6 +163,8 @@ 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 834e43de0daf..898a1d0c38dc 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -47,14 +47,34 @@ 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) { unsigned long size; + void *swapfn = NULL; + + if (IS_ENABLED(CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE)) + swapfn = jump_label_swap; 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, swapfn); } static void jump_label_update(struct static_key *key); -- 2.17.1
WARNING: multiple messages have this Message-ID (diff)
From: ard.biesheuvel@linaro.org (Ard Biesheuvel) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 2/9] kernel/jump_label: implement generic support for relative references Date: Tue, 18 Sep 2018 23:51:37 -0700 [thread overview] Message-ID: <20180919065144.25010-3-ard.biesheuvel@linaro.org> (raw) In-Reply-To: <20180919065144.25010-1-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 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 | 22 ++++++++++++++- 3 files changed, 52 insertions(+), 1 deletion(-) diff --git a/arch/Kconfig b/arch/Kconfig index 6801123932a5..9d329608913e 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -359,6 +359,9 @@ 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 2eadff9b3b90..2768a925bafa 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 { + s32 code; + s32 target; + long key; // key may be far away from the core kernel under KASLR +}; + +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) +{ + long offset = entry->key & ~1L; + + return (struct static_key *)((unsigned long)&entry->key + offset); +} + +#else static inline unsigned long jump_entry_code(const struct jump_entry *entry) { @@ -137,6 +163,8 @@ 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 834e43de0daf..898a1d0c38dc 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -47,14 +47,34 @@ 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) { unsigned long size; + void *swapfn = NULL; + + if (IS_ENABLED(CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE)) + swapfn = jump_label_swap; 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, swapfn); } static void jump_label_update(struct static_key *key); -- 2.17.1
next prev parent reply other threads:[~2018-09-19 6:52 UTC|newest] Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-09-19 6:51 [PATCH v3 0/9] add support for relative references in jump tables Ard Biesheuvel 2018-09-19 6:51 ` Ard Biesheuvel 2018-09-19 6:51 ` [PATCH v3 1/9] kernel/jump_label: abstract jump_entry member accessors Ard Biesheuvel 2018-09-19 6:51 ` Ard Biesheuvel 2018-09-27 16:00 ` [tip:core/core] jump_label: Abstract " tip-bot for Ard Biesheuvel 2018-09-19 6:51 ` Ard Biesheuvel [this message] 2018-09-19 6:51 ` [PATCH v3 2/9] kernel/jump_label: implement generic support for relative references Ard Biesheuvel 2018-09-27 16:01 ` [tip:core/core] jump_label: Implement " tip-bot for Ard Biesheuvel 2018-09-19 6:51 ` [PATCH v3 3/9] arm64/kernel: jump_label: switch to " Ard Biesheuvel 2018-09-19 6:51 ` Ard Biesheuvel 2018-09-27 16:02 ` [tip:core/core] arm64/kernel: jump_label: Switch " tip-bot for Ard Biesheuvel 2018-09-19 6:51 ` [PATCH v3 4/9] x86: add support for 64-bit place relative relocations Ard Biesheuvel 2018-09-19 6:51 ` Ard Biesheuvel 2018-09-27 16:02 ` [tip:core/core] x86: Add " tip-bot for Ard Biesheuvel 2018-09-19 6:51 ` [PATCH v3 5/9] x86: jump_label: switch to jump_entry accessors Ard Biesheuvel 2018-09-19 6:51 ` Ard Biesheuvel 2018-09-27 16:03 ` [tip:core/core] x86/jump_label: Switch " tip-bot for Ard Biesheuvel 2018-09-19 6:51 ` [PATCH v3 6/9] x86/kernel: jump_table: use relative references Ard Biesheuvel 2018-09-19 6:51 ` Ard Biesheuvel 2018-09-27 16:03 ` [tip:core/core] x86/jump_table: Use " tip-bot for Ard Biesheuvel 2018-09-19 6:51 ` [PATCH v3 7/9] jump_label: annotate entries that operate on __init code earlier Ard Biesheuvel 2018-09-19 6:51 ` Ard Biesheuvel 2018-09-27 16:04 ` [tip:core/core] jump_label: Annotate " tip-bot for Ard Biesheuvel 2018-09-19 6:51 ` [PATCH v3 8/9] jump_table: move entries into ro_after_init region Ard Biesheuvel 2018-09-19 6:51 ` Ard Biesheuvel 2018-09-27 16:04 ` [tip:core/core] jump_table: Move " tip-bot for Ard Biesheuvel 2018-09-30 15:42 ` [PATCH v3 8/9] jump_table: move " Guenter Roeck 2018-09-30 15:42 ` Guenter Roeck 2018-09-19 6:51 ` [PATCH v3 9/9] s390/jump_label: switch to relative references Ard Biesheuvel 2018-09-19 6:51 ` Ard Biesheuvel 2018-09-27 16:05 ` [tip:core/core] s390/jump_label: Switch " tip-bot for Heiko Carstens 2018-09-19 13:08 ` [PATCH v3 0/9] add support for relative references in jump tables Peter Zijlstra 2018-09-19 13:08 ` Peter Zijlstra 2018-09-27 15:22 ` Ard Biesheuvel 2018-09-27 15:22 ` Ard Biesheuvel 2018-09-27 15:46 ` Kees Cook 2018-09-27 15:46 ` Kees Cook
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=20180919065144.25010-3-ard.biesheuvel@linaro.org \ --to=ard.biesheuvel@linaro.org \ --cc=arnd@arndb.de \ --cc=catalin.marinas@arm.com \ --cc=heiko.carstens@de.ibm.com \ --cc=jeyu@kernel.org \ --cc=keescook@chromium.org \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-s390@vger.kernel.org \ --cc=mingo@redhat.com \ --cc=peterz@infradead.org \ --cc=rostedt@goodmis.org \ --cc=schwidefsky@de.ibm.com \ --cc=tglx@linutronix.de \ --cc=will.deacon@arm.com \ /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: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.