Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762322AbZFNPw4 (ORCPT ); Sun, 14 Jun 2009 11:52:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762311AbZFNPws (ORCPT ); Sun, 14 Jun 2009 11:52:48 -0400 Received: from mail-pz0-f187.google.com ([209.85.222.187]:46382 "EHLO mail-pz0-f187.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754786AbZFNPwr (ORCPT ); Sun, 14 Jun 2009 11:52:47 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; b=HS1HnZVzAGtFErExdcs4x9QhnLc7JgEfrTWeUfiUR/0qco1RgQ1vuIliSfUiz7bp+F vpL0MxpmvYhczaYrIyhueN7hqMVuTYxupS9xg4w65XSlIB4A0UvT1Rird1krGoOInMC3 AO7F8o6B4C+2J3c923kIusN9RWj4NESVjyiBo= From: Wu Zhangjin To: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org Cc: Wang Liming , Wu Zhangjin , Steven Rostedt , Ralf Baechle , Thomas Gleixner , Nicholas Mc Guire , Ingo Molnar Subject: [PATCH v3] mips dynamic function tracer support Date: Sun, 14 Jun 2009 23:52:39 +0800 Message-Id: <46cdb2d6a53dc89e4f0587593961f48e3496f147.1244994151.git.wuzj@lemote.com> X-Mailer: git-send-email 1.6.3.1 In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9541 Lines: 372 From: Wu Zhangjin dynamic function tracer need to replace "nop" to "jumps & links" and something reversely. Reviewed-by: Steven Rostedt Signed-off-by: Wu Zhangjin --- arch/mips/Kconfig | 3 + arch/mips/include/asm/ftrace.h | 10 ++ arch/mips/kernel/Makefile | 2 + arch/mips/kernel/ftrace.c | 207 ++++++++++++++++++++++++++++++++++++++++ arch/mips/kernel/mcount.S | 31 ++++++ scripts/recordmcount.pl | 20 ++++ 6 files changed, 273 insertions(+), 0 deletions(-) create mode 100644 arch/mips/kernel/ftrace.c diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 2e2fdbe..0857239 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -6,6 +6,9 @@ config MIPS select HAVE_ARCH_KGDB select HAVE_FUNCTION_TRACER select HAVE_FUNCTION_TRACE_MCOUNT_TEST + select HAVE_DYNAMIC_FTRACE + select HAVE_FTRACE_MCOUNT_RECORD + select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE # Horrible source of confusion. Die, die, die ... select EMBEDDED select RTC_LIB diff --git a/arch/mips/include/asm/ftrace.h b/arch/mips/include/asm/ftrace.h index 5f8ebcf..b4970c9 100644 --- a/arch/mips/include/asm/ftrace.h +++ b/arch/mips/include/asm/ftrace.h @@ -19,6 +19,16 @@ extern void _mcount(void); #define mcount _mcount +#ifdef CONFIG_DYNAMIC_FTRACE +/* reloction of mcount call site is the same as the address */ +static inline unsigned long ftrace_call_adjust(unsigned long addr) +{ + return addr; +} + +struct dyn_arch_ftrace { +}; +#endif /* CONFIG_DYNAMIC_FTRACE */ #endif /* __ASSEMBLY__ */ #endif /* CONFIG_FUNCTION_TRACER */ #endif /* _ASM_MIPS_FTRACE_H */ diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile index 559a820..8dabcc6 100644 --- a/arch/mips/kernel/Makefile +++ b/arch/mips/kernel/Makefile @@ -10,6 +10,7 @@ obj-y += cpu-probe.o branch.o entry.o genex.o irq.o process.o \ ifdef CONFIG_FUNCTION_TRACER # Do not profile debug and lowlevel utilities +CFLAGS_REMOVE_ftrace.o = -pg CFLAGS_REMOVE_early_printk.o = -pg endif @@ -30,6 +31,7 @@ obj-$(CONFIG_STACKTRACE) += stacktrace.o obj-$(CONFIG_MODULES) += mips_ksyms.o module.o obj-$(CONFIG_FUNCTION_TRACER) += mcount.o +obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o obj-$(CONFIG_CPU_LOONGSON2) += r4k_fpu.o r4k_switch.o obj-$(CONFIG_CPU_MIPS32) += r4k_fpu.o r4k_switch.o diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c new file mode 100644 index 0000000..ad490cc --- /dev/null +++ b/arch/mips/kernel/ftrace.c @@ -0,0 +1,207 @@ +/* + * Code for replacing ftrace calls with jumps. + * + * Copyright (C) 2007-2008 Steven Rostedt + * Copyright (C) 2009 DSLab, Lanzhou University, China + * Author: Wu Zhangjin + * + * Thanks goes to Steven Rostedt for writing the original x86 version. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +#ifdef CONFIG_DYNAMIC_FTRACE + +#define JAL 0x0c000000 /* jump & link: ip --> ra, jump to target */ +#define ADDR_MASK 0x03ffffff /* op_code|addr : 31...26|25 ....0 */ + +static unsigned int ftrace_nop = 0x00000000; + +static unsigned char *ftrace_call_replace(unsigned long op_code, + unsigned long addr) +{ + static unsigned int op; + + op = op_code | ((addr >> 2) & ADDR_MASK); + + return (unsigned char *) &op; +} + +static atomic_t nmi_running = ATOMIC_INIT(0); +static int mod_code_status; /* holds return value of text write */ +static int mod_code_write; /* set when NMI should do the write */ +static void *mod_code_ip; /* holds the IP to write to */ +static void *mod_code_newcode; /* holds the text to write to the IP */ + +static unsigned nmi_wait_count; +static atomic_t nmi_update_count = ATOMIC_INIT(0); + +int ftrace_arch_read_dyn_info(char *buf, int size) +{ + int r; + + r = snprintf(buf, size, "%u %u", + nmi_wait_count, atomic_read(&nmi_update_count)); + return r; +} + +static void ftrace_mod_code(void) +{ + /* + * Yes, more than one CPU process can be writing to mod_code_status. + * (and the code itself) + * But if one were to fail, then they all should, and if one were + * to succeed, then they all should. + */ + mod_code_status = probe_kernel_write(mod_code_ip, mod_code_newcode, + MCOUNT_INSN_SIZE); + + /* if we fail, then kill any new writers */ + if (mod_code_status) + mod_code_write = 0; +} + +void ftrace_nmi_enter(void) +{ + atomic_inc(&nmi_running); + /* Must have nmi_running seen before reading write flag */ + smp_mb(); + if (mod_code_write) { + ftrace_mod_code(); + atomic_inc(&nmi_update_count); + } +} + +void ftrace_nmi_exit(void) +{ + /* Finish all executions before clearing nmi_running */ + smp_wmb(); + atomic_dec(&nmi_running); +} + +static void wait_for_nmi(void) +{ + int waited = 0; + + while (atomic_read(&nmi_running)) { + waited = 1; + cpu_relax(); + } + + if (waited) + nmi_wait_count++; +} + +static int do_ftrace_mod_code(unsigned long ip, void *new_code) +{ + mod_code_ip = (void *) ip; + mod_code_newcode = new_code; + + /* The buffers need to be visible before we let NMIs write them */ + smp_wmb(); + + mod_code_write = 1; + + /* Make sure write bit is visible before we wait on NMIs */ + smp_mb(); + + wait_for_nmi(); + + /* Make sure all running NMIs have finished before we write the code */ + smp_mb(); + + ftrace_mod_code(); + + /* Make sure the write happens before clearing the bit */ + smp_wmb(); + + mod_code_write = 0; + + /* make sure NMIs see the cleared bit */ + smp_mb(); + + wait_for_nmi(); + + return mod_code_status; +} + +static unsigned char *ftrace_nop_replace(void) +{ + return (unsigned char *) &ftrace_nop; +} + +static int +ftrace_modify_code(unsigned long ip, unsigned char *old_code, + unsigned char *new_code) +{ + unsigned char replaced[MCOUNT_INSN_SIZE]; + + /* read the text we want to modify */ + if (probe_kernel_read(replaced, (void *) ip, MCOUNT_INSN_SIZE)) + return -EFAULT; + + /* Make sure it is what we expect it to be */ + if (memcmp(replaced, old_code, MCOUNT_INSN_SIZE) != 0) + return -EINVAL; + + /* replace the text with the new text */ + if (do_ftrace_mod_code(ip, new_code)) + return -EPERM; + + return 0; +} + +int ftrace_make_nop(struct module *mod, + struct dyn_ftrace *rec, unsigned long addr) +{ + unsigned char *new, *old; + + old = ftrace_call_replace(JAL, addr); + new = ftrace_nop_replace(); + + return ftrace_modify_code(rec->ip, old, new); +} + +int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + unsigned char *new, *old; + + old = ftrace_nop_replace(); + new = ftrace_call_replace(JAL, addr); + + return ftrace_modify_code(rec->ip, old, new); +} + +int ftrace_update_ftrace_func(ftrace_func_t func) +{ + unsigned long ip = (unsigned long) (&ftrace_call); + unsigned char old[MCOUNT_INSN_SIZE], *new; + int ret; + + memcpy(old, &ftrace_call, MCOUNT_INSN_SIZE); + new = ftrace_call_replace(JAL, (unsigned long) func); + ret = ftrace_modify_code(ip, old, new); + + return ret; +} + +int __init ftrace_dyn_arch_init(void *data) +{ + /* The return code is retured via data */ + *(unsigned long *) data = 0; + + return 0; +} +#endif /* CONFIG_DYNAMIC_FTRACE */ diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S index 268724e..723ace2 100644 --- a/arch/mips/kernel/mcount.S +++ b/arch/mips/kernel/mcount.S @@ -67,6 +67,35 @@ move ra, $1 .endm +#ifdef CONFIG_DYNAMIC_FTRACE + +LEAF(_mcount) + RESTORE_SP_FOR_32BIT + RETURN_BACK + END(_mcount) + +NESTED(ftrace_caller, PT_SIZE, ra) + RESTORE_SP_FOR_32BIT + lw t0, function_trace_stop + bnez t0, ftrace_stub + nop + + MCOUNT_SAVE_REGS + + MCOUNT_SET_ARGS + .globl ftrace_call +ftrace_call: + jal ftrace_stub + nop + + MCOUNT_RESTORE_REGS + .globl ftrace_stub +ftrace_stub: + RETURN_BACK + END(ftrace_caller) + +#else /* ! CONFIG_DYNAMIC_FTRACE */ + NESTED(_mcount, PT_SIZE, ra) RESTORE_SP_FOR_32BIT PTR_L t0, function_trace_stop @@ -94,5 +123,7 @@ ftrace_stub: RETURN_BACK END(_mcount) +#endif /* ! CONFIG_DYNAMIC_FTRACE */ + .set at .set reorder diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl index f1e3e9c..533d3bf 100755 --- a/scripts/recordmcount.pl +++ b/scripts/recordmcount.pl @@ -213,6 +213,26 @@ if ($arch eq "x86_64") { if ($is_module eq "0") { $cc .= " -mconstant-gp"; } + +} elsif ($arch eq "mips") { + $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$"; + $objdump .= " -Melf-trad".$endian."mips "; + + if ($endian eq "big") { + $endian = " -EB "; + $ld .= " -melf".$bits."btsmip"; + } else { + $endian = " -EL "; + $ld .= " -melf".$bits."ltsmip"; + } + + $cc .= " -mno-abicalls -fno-pic -mabi=" . $bits . $endian; + $ld .= $endian; + + if ($bits == 64) { + $type = ".dword"; + } + } else { die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD"; } -- 1.6.0.4 -- 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/