Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753210Ab0G0Uyt (ORCPT ); Tue, 27 Jul 2010 16:54:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45398 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752943Ab0G0Uyr (ORCPT ); Tue, 27 Jul 2010 16:54:47 -0400 Date: Tue, 27 Jul 2010 16:54:18 -0400 From: Jason Baron To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, mathieu.desnoyers@polymtl.ca, hpa@zytor.com, tglx@linutronix.de, rostedt@goodmis.org, andi@firstfloor.org, roland@redhat.com, rth@redhat.com, mhiramat@redhat.com, fweisbec@gmail.com, avi@redhat.com, davem@davemloft.net, vgoyal@redhat.com, sam@ravnborg.org, tony@bakeyournoodle.com Message-Id: In-Reply-To: References: Subject: [PATCH 03/12] jump label v10: move ftrace_dyn_arch_init to common code Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 11765 Lines: 389 Move Steve's code for finding the best 5-byte no-op from ftrace.c to alternative.c. The idea is that other consumers (in this case jump label) want to make use of that code. I've created a global: 'char ideal_nop[5]', that is setup during setup_arch that can be used. Signed-off-by: Jason Baron --- arch/x86/include/asm/alternative.h | 14 +++++++ arch/x86/kernel/alternative.c | 72 +++++++++++++++++++++++++++++++++++- arch/x86/kernel/ftrace.c | 70 +---------------------------------- arch/x86/kernel/setup.c | 3 + include/linux/jump_label.h | 10 ++++- kernel/jump_label.c | 32 ++++++++++++++++ kernel/trace/ftrace.c | 13 +------ 7 files changed, 130 insertions(+), 84 deletions(-) diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h index bc6abb7..963f5f9 100644 --- a/arch/x86/include/asm/alternative.h +++ b/arch/x86/include/asm/alternative.h @@ -4,6 +4,7 @@ #include #include #include +#include #include /* @@ -160,6 +161,8 @@ static inline void apply_paravirt(struct paravirt_patch_site *start, #define __parainstructions_end NULL #endif +extern void *text_poke_early(void *addr, const void *opcode, size_t len); + /* * Clear and restore the kernel write-protection flag on the local CPU. * Allows the kernel to edit read-only pages. @@ -180,4 +183,15 @@ static inline void apply_paravirt(struct paravirt_patch_site *start, extern void *text_poke(void *addr, const void *opcode, size_t len); extern void *text_poke_smp(void *addr, const void *opcode, size_t len); +#if defined(CONFIG_DYNAMIC_FTRACE) || defined(HAVE_JUMP_LABEL) +#define IDEAL_NOP_SIZE_5 5 +extern unsigned char ideal_nop5[IDEAL_NOP_SIZE_5]; +extern int arch_init_ideal_nop5(void); +#else +static inline int arch_init_ideal_nop5(void) +{ + return 0; +} +#endif + #endif /* _ASM_X86_ALTERNATIVE_H */ diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index f65ab8b..df5a4f2 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -195,7 +195,7 @@ static void __init_or_module add_nops(void *insns, unsigned int len) extern struct alt_instr __alt_instructions[], __alt_instructions_end[]; extern s32 __smp_locks[], __smp_locks_end[]; -static void *text_poke_early(void *addr, const void *opcode, size_t len); +void *text_poke_early(void *addr, const void *opcode, size_t len); /* Replace instructions with better alternatives for this CPU type. This runs before SMP is initialized to avoid SMP problems with @@ -522,7 +522,7 @@ void __init alternative_instructions(void) * instructions. And on the local CPU you need to be protected again NMI or MCE * handlers seeing an inconsistent instruction while you patch. */ -static void *__init_or_module text_poke_early(void *addr, const void *opcode, +void *__init_or_module text_poke_early(void *addr, const void *opcode, size_t len) { unsigned long flags; @@ -641,3 +641,71 @@ void *__kprobes text_poke_smp(void *addr, const void *opcode, size_t len) return addr; } +#if defined(CONFIG_DYNAMIC_FTRACE) || defined(HAVE_JUMP_LABEL) + +unsigned char ideal_nop5[IDEAL_NOP_SIZE_5]; + +int __init arch_init_ideal_nop5(void) +{ + extern const unsigned char ftrace_test_p6nop[]; + extern const unsigned char ftrace_test_nop5[]; + extern const unsigned char ftrace_test_jmp[]; + int faulted = 0; + unsigned long flags; + + local_irq_save(flags); + /* + * There is no good nop for all x86 archs. + * We will default to using the P6_NOP5, but first we + * will test to make sure that the nop will actually + * work on this CPU. If it faults, we will then + * go to a lesser efficient 5 byte nop. If that fails + * we then just use a jmp as our nop. This isn't the most + * efficient nop, but we can not use a multi part nop + * since we would then risk being preempted in the middle + * of that nop, and if we enabled tracing then, it might + * cause a system crash. + * + * TODO: check the cpuid to determine the best nop. + */ + asm volatile ( + "ftrace_test_jmp:" + "jmp ftrace_test_p6nop\n" + "nop\n" + "nop\n" + "nop\n" /* 2 byte jmp + 3 bytes */ + "ftrace_test_p6nop:" + P6_NOP5 + "jmp 1f\n" + "ftrace_test_nop5:" + ".byte 0x66,0x66,0x66,0x66,0x90\n" + "1:" + ".section .fixup, \"ax\"\n" + "2: movl $1, %0\n" + " jmp ftrace_test_nop5\n" + "3: movl $2, %0\n" + " jmp 1b\n" + ".previous\n" + _ASM_EXTABLE(ftrace_test_p6nop, 2b) + _ASM_EXTABLE(ftrace_test_nop5, 3b) + : "=r"(faulted) : "0" (faulted)); + + switch (faulted) { + case 0: + pr_info("converting mcount calls to 0f 1f 44 00 00\n"); + memcpy(ideal_nop5, ftrace_test_p6nop, IDEAL_NOP_SIZE_5); + break; + case 1: + pr_info("converting mcount calls to 66 66 66 66 90\n"); + memcpy(ideal_nop5, ftrace_test_nop5, IDEAL_NOP_SIZE_5); + break; + case 2: + pr_info("converting mcount calls to jmp . + 5\n"); + memcpy(ideal_nop5, ftrace_test_jmp, IDEAL_NOP_SIZE_5); + break; + } + + local_irq_restore(flags); + return 0; +} +#endif diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index cd37469..ba2e0d9 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -257,14 +257,9 @@ do_ftrace_mod_code(unsigned long ip, void *new_code) return mod_code_status; } - - - -static unsigned char ftrace_nop[MCOUNT_INSN_SIZE]; - static unsigned char *ftrace_nop_replace(void) { - return ftrace_nop; + return ideal_nop5; } static int @@ -336,69 +331,6 @@ int ftrace_update_ftrace_func(ftrace_func_t func) return ret; } -int __init ftrace_dyn_arch_init(void *data) -{ - extern const unsigned char ftrace_test_p6nop[]; - extern const unsigned char ftrace_test_nop5[]; - extern const unsigned char ftrace_test_jmp[]; - int faulted = 0; - - /* - * There is no good nop for all x86 archs. - * We will default to using the P6_NOP5, but first we - * will test to make sure that the nop will actually - * work on this CPU. If it faults, we will then - * go to a lesser efficient 5 byte nop. If that fails - * we then just use a jmp as our nop. This isn't the most - * efficient nop, but we can not use a multi part nop - * since we would then risk being preempted in the middle - * of that nop, and if we enabled tracing then, it might - * cause a system crash. - * - * TODO: check the cpuid to determine the best nop. - */ - asm volatile ( - "ftrace_test_jmp:" - "jmp ftrace_test_p6nop\n" - "nop\n" - "nop\n" - "nop\n" /* 2 byte jmp + 3 bytes */ - "ftrace_test_p6nop:" - P6_NOP5 - "jmp 1f\n" - "ftrace_test_nop5:" - ".byte 0x66,0x66,0x66,0x66,0x90\n" - "1:" - ".section .fixup, \"ax\"\n" - "2: movl $1, %0\n" - " jmp ftrace_test_nop5\n" - "3: movl $2, %0\n" - " jmp 1b\n" - ".previous\n" - _ASM_EXTABLE(ftrace_test_p6nop, 2b) - _ASM_EXTABLE(ftrace_test_nop5, 3b) - : "=r"(faulted) : "0" (faulted)); - - switch (faulted) { - case 0: - pr_info("converting mcount calls to 0f 1f 44 00 00\n"); - memcpy(ftrace_nop, ftrace_test_p6nop, MCOUNT_INSN_SIZE); - break; - case 1: - pr_info("converting mcount calls to 66 66 66 66 90\n"); - memcpy(ftrace_nop, ftrace_test_nop5, MCOUNT_INSN_SIZE); - break; - case 2: - pr_info("converting mcount calls to jmp . + 5\n"); - memcpy(ftrace_nop, ftrace_test_jmp, MCOUNT_INSN_SIZE); - break; - } - - /* The return code is retured via data */ - *(unsigned long *)data = 0; - - return 0; -} #endif #ifdef CONFIG_FUNCTION_GRAPH_TRACER diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index b008e78..cb28d82 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -49,6 +49,7 @@ #include #include #include +#include #include #include @@ -1069,6 +1070,8 @@ void __init setup_arch(char **cmdline_p) x86_init.oem.banner(); mcheck_init(); + + arch_init_ideal_nop5(); } #ifdef CONFIG_X86_32 diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index 9ac29c0..fc2b181 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -11,6 +11,8 @@ enum jump_label_type { JUMP_LABEL_DISABLE }; +struct module; + #ifdef HAVE_JUMP_LABEL extern struct jump_entry __start___jump_table[]; @@ -23,8 +25,9 @@ extern struct jump_entry __stop___jump_table[]; extern void arch_jump_label_transform(struct jump_entry *entry, enum jump_label_type type); -extern const u8 *arch_jump_label_get_nop(void); extern void jump_label_update(const char *name, enum jump_label_type type); +extern void jump_label_apply_nops(struct module *mod); +extern void arch_jump_label_text_poke_early(jump_label_t addr); #define enable_jump_label(name) \ jump_label_update(name, JUMP_LABEL_ENABLE); @@ -52,6 +55,11 @@ static inline int disable_jump_label(const char *name) return 0; } +static inline int jump_label_apply_nops(struct module *mod) +{ + return 0; +} + #endif #endif diff --git a/kernel/jump_label.c b/kernel/jump_label.c index ecca4f4..ebe9145 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -11,6 +11,7 @@ #include #include #include +#include #ifdef HAVE_JUMP_LABEL @@ -185,10 +186,18 @@ void jump_label_update(const char *name, enum jump_label_type type) static __init int init_jump_label(void) { int ret; + struct jump_entry *iter_start = __start___jump_table; + struct jump_entry *iter_stop = __stop___jump_table; + struct jump_entry *iter; mutex_lock(&jump_label_mutex); ret = build_jump_label_hashtable(__start___jump_table, __stop___jump_table); + iter = iter_start; + while (iter < iter_stop) { + arch_jump_label_text_poke_early(iter->code); + iter++; + } mutex_unlock(&jump_label_mutex); return ret; } @@ -299,6 +308,29 @@ static int jump_label_module_notify(struct notifier_block *self, unsigned long v return ret; } +/*** + * apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop() + * @mod: module to patch + * + * Allow for run-time selection of the optimal nops. Before the module + * loads patch these with arch_get_jump_label_nop(), which is specified by + * the arch specific jump label code. + */ +void jump_label_apply_nops(struct module *mod) +{ + struct jump_entry *iter; + + /* if the module doesn't have jump label entries, just return */ + if (!mod->num_jump_entries) + return; + + iter = mod->jump_entries; + while (iter < mod->jump_entries + mod->num_jump_entries) { + arch_jump_label_text_poke_early(iter->code); + iter++; + } +} + struct notifier_block jump_label_module_nb = { .notifier_call = jump_label_module_notify, .priority = 0, diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 0d88ce9..1a1cc47 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2749,20 +2749,9 @@ extern unsigned long __stop_mcount_loc[]; void __init ftrace_init(void) { - unsigned long count, addr, flags; + unsigned long count; int ret; - /* Keep the ftrace pointer to the stub */ - addr = (unsigned long)ftrace_stub; - - local_irq_save(flags); - ftrace_dyn_arch_init(&addr); - local_irq_restore(flags); - - /* ftrace_dyn_arch_init places the return code in addr */ - if (addr) - goto failed; - count = __stop_mcount_loc - __start_mcount_loc; ret = ftrace_dyn_table_alloc(count); -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/