From 7d241ff0567b9503d79ee775c40927d09b509f83 Mon Sep 17 00:00:00 2001 From: Michal Simek Date: Thu, 10 Dec 2009 14:15:44 +0100 Subject: [PATCH] microblaze: ftrace: Add dynamic trace support With dynamic function tracer, by default, _mcount is defined as an "empty" function, it returns directly without any more action. When enabling it in user-space, it will jump to a real tracing function(ftrace_caller), and do the real job for us. Differ from the static function tracer, dynamic function tracer provides two functions ftrace_make_call()/ftrace_make_nop() to enable/disable the tracing of some indicated kernel functions(set_ftrace_filter). In the kernel version, there is only one "_mcount" string for every kernel function, so, we just need to match this one in mcount_regex of scripts/recordmcount.pl. For more information please look at code and Documentation/trace folder. Steven ACK that scripts/recordmcount.pl part. Acked-by: Steven Rostedt Signed-off-by: Michal Simek --- arch/microblaze/Kconfig | 2 + arch/microblaze/include/asm/ftrace.h | 11 ++ arch/microblaze/kernel/Makefile | 2 +- arch/microblaze/kernel/ftrace.c | 151 +++++++++++++++++++++++++++ arch/microblaze/kernel/mcount.S | 13 +++ scripts/recordmcount.pl | 3 + 6 files changed, 181 insertions(+), 1 deletion(-) create mode 100644 arch/microblaze/kernel/ftrace.c diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig index cccf3adfae50..102d73aa1063 100644 --- a/arch/microblaze/Kconfig +++ b/arch/microblaze/Kconfig @@ -8,6 +8,8 @@ config MICROBLAZE select HAVE_LMB select HAVE_FUNCTION_TRACER select HAVE_FUNCTION_TRACE_MCOUNT_TEST + select HAVE_DYNAMIC_FTRACE + select HAVE_FTRACE_MCOUNT_RECORD select USB_ARCH_HAS_EHCI select ARCH_WANT_OPTIONAL_GPIOLIB diff --git a/arch/microblaze/include/asm/ftrace.h b/arch/microblaze/include/asm/ftrace.h index 22beec58c021..fd2fa2eca62f 100644 --- a/arch/microblaze/include/asm/ftrace.h +++ b/arch/microblaze/include/asm/ftrace.h @@ -11,5 +11,16 @@ extern void _mcount(void); extern void ftrace_call_graph(void); #endif +#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 /* CONFIG_FUNCTION_TRACER */ #endif /* _ASM_MICROBLAZE_FTRACE */ diff --git a/arch/microblaze/kernel/Makefile b/arch/microblaze/kernel/Makefile index d5ee3264cd7d..b07594eccf9b 100644 --- a/arch/microblaze/kernel/Makefile +++ b/arch/microblaze/kernel/Makefile @@ -27,6 +27,6 @@ obj-$(CONFIG_HEART_BEAT) += heartbeat.o obj-$(CONFIG_MODULES) += microblaze_ksyms.o module.o obj-$(CONFIG_MMU) += misc.o obj-$(CONFIG_STACKTRACE) += stacktrace.o -obj-$(CONFIG_FUNCTION_TRACER) += mcount.o +obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o mcount.o obj-y += entry$(MMU).o diff --git a/arch/microblaze/kernel/ftrace.c b/arch/microblaze/kernel/ftrace.c new file mode 100644 index 000000000000..c1889b101cb8 --- /dev/null +++ b/arch/microblaze/kernel/ftrace.c @@ -0,0 +1,151 @@ +/* + * Ftrace support for Microblaze. + * + * Copyright (C) 2009 Michal Simek + * Copyright (C) 2009 PetaLogix + * + * Based on MIPS and PowerPC ftrace code + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#include +#include + +#ifdef CONFIG_DYNAMIC_FTRACE +/* save value to addr - it is save to do it in asm */ +static int ftrace_modify_code(unsigned long addr, unsigned int value) +{ + int faulted = 0; + + __asm__ __volatile__(" 1: swi %2, %1, 0; \ + addik %0, r0, 0; \ + 2: \ + .section .fixup, \"ax\"; \ + 3: brid 2b; \ + addik %0, r0, 1; \ + .previous; \ + .section __ex_table,\"a\"; \ + .word 1b,3b; \ + .previous;" \ + : "=r" (faulted) + : "r" (addr), "r" (value) + ); + + if (unlikely(faulted)) + return -EFAULT; + + return 0; +} + +#define MICROBLAZE_NOP 0x80000000 +#define MICROBLAZE_BRI 0xb800000C + +static unsigned int recorded; /* if save was or not */ +static unsigned int imm; /* saving whole imm instruction */ + +/* There are two approaches howto solve ftrace_make nop function - look below */ +#undef USE_FTRACE_NOP + +#ifdef USE_FTRACE_NOP +static unsigned int bralid; /* saving whole bralid instruction */ +#endif + +int ftrace_make_nop(struct module *mod, + struct dyn_ftrace *rec, unsigned long addr) +{ + /* we have this part of code which we are working with + * b000c000 imm -16384 + * b9fc8e30 bralid r15, -29136 // c0008e30 <_mcount> + * 80000000 or r0, r0, r0 + * + * The first solution (!USE_FTRACE_NOP-could be called branch solution) + * b000c000 bri 12 (0xC - jump to any other instruction) + * b9fc8e30 bralid r15, -29136 // c0008e30 <_mcount> + * 80000000 or r0, r0, r0 + * any other instruction + * + * The second solution (USE_FTRACE_NOP) - no jump just nops + * 80000000 or r0, r0, r0 + * 80000000 or r0, r0, r0 + * 80000000 or r0, r0, r0 + */ + int ret = 0; + + if (recorded == 0) { + recorded = 1; + imm = *(unsigned int *)rec->ip; + pr_debug("%s: imm:0x%x\n", __func__, imm); +#ifdef USE_FTRACE_NOP + bralid = *(unsigned int *)(rec->ip + 4); + pr_debug("%s: bralid 0x%x\n", __func__, bralid); +#endif /* USE_FTRACE_NOP */ + } + +#ifdef USE_FTRACE_NOP + ret = ftrace_modify_code(rec->ip, MICROBLAZE_NOP); + ret += ftrace_modify_code(rec->ip + 4, MICROBLAZE_NOP); +#else /* USE_FTRACE_NOP */ + ret = ftrace_modify_code(rec->ip, MICROBLAZE_BRI); +#endif /* USE_FTRACE_NOP */ + return ret; +} + +static int ret_addr; /* initialized as 0 by default */ + +/* I believe that first is called ftrace_make_nop before this function */ +int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + int ret; + ret_addr = addr; /* saving where the barrier jump is */ + pr_debug("%s: addr:0x%x, rec->ip: 0x%x, imm:0x%x\n", + __func__, (unsigned int)addr, (unsigned int)rec->ip, imm); + ret = ftrace_modify_code(rec->ip, imm); +#ifdef USE_FTRACE_NOP + pr_debug("%s: bralid:0x%x\n", __func__, bralid); + ret += ftrace_modify_code(rec->ip + 4, bralid); +#endif /* USE_FTRACE_NOP */ + return ret; +} + +int __init ftrace_dyn_arch_init(void *data) +{ + /* The return code is retured via data */ + *(unsigned long *)data = 0; + + return 0; +} + +int ftrace_update_ftrace_func(ftrace_func_t func) +{ + unsigned long ip = (unsigned long)(&ftrace_call); + unsigned int upper = (unsigned int)func; + unsigned int lower = (unsigned int)func; + int ret = 0; + + /* create proper saving to ftrace_call poll */ + upper = 0xb0000000 + (upper >> 16); /* imm func_upper */ + lower = 0x32800000 + (lower & 0xFFFF); /* addik r20, r0, func_lower */ + + pr_debug("%s: func=0x%x, ip=0x%x, upper=0x%x, lower=0x%x\n", + __func__, (unsigned int)func, (unsigned int)ip, upper, lower); + + /* save upper and lower code */ + ret = ftrace_modify_code(ip, upper); + ret += ftrace_modify_code(ip + 4, lower); + + /* We just need to remove the rtsd r15, 8 by NOP */ + BUG_ON(!ret_addr); + if (ret_addr) + ret += ftrace_modify_code(ret_addr, MICROBLAZE_NOP); + else + ret = 1; /* fault */ + + /* All changes are done - lets do caches consistent */ + flush_icache(); + return ret; +} + +#endif /* CONFIG_DYNAMIC_FTRACE */ diff --git a/arch/microblaze/kernel/mcount.S b/arch/microblaze/kernel/mcount.S index 97eef3eea944..30aaf8fb55b2 100644 --- a/arch/microblaze/kernel/mcount.S +++ b/arch/microblaze/kernel/mcount.S @@ -83,6 +83,12 @@ ENTRY(ftrace_stub) nop; ENTRY(_mcount) +#ifdef CONFIG_DYNAMIC_FTRACE +ENTRY(ftrace_caller) + /* MS: It is just barrier which is removed from C code */ + rtsd r15, 8 + nop +#endif /* CONFIG_DYNAMIC_FTRACE */ SAVE_REGS swi r15, r1, 0; /* MS: HAVE_FUNCTION_TRACE_MCOUNT_TEST begin of checking */ @@ -90,12 +96,19 @@ ENTRY(_mcount) bneid r5, end; nop; /* MS: HAVE_FUNCTION_TRACE_MCOUNT_TEST end of checking */ +#ifndef CONFIG_DYNAMIC_FTRACE /* MS: test function trace if is taken or not */ lwi r20, r0, ftrace_trace_function; addik r6, r0, ftrace_stub; cmpu r5, r20, r6; /* ftrace_trace_function != ftrace_stub */ beqid r5, end; /* MS: not taken -> jump over */ nop; +#else /* CONFIG_DYNAMIC_FTRACE */ +NOALIGN_ENTRY(ftrace_call) +/* instruction for setup imm FUNC_part1, addik r20, r0, FUNC_part2 */ + nop + nop +#endif /* CONFIG_DYNAMIC_FTRACE */ /* static normal trace */ lwi r6, r1, 120; /* MS: load parent addr */ addik r5, r15, 0; /* MS: load current function addr */ diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl index f0d14452632b..9cf0a6fad6ba 100755 --- a/scripts/recordmcount.pl +++ b/scripts/recordmcount.pl @@ -295,6 +295,9 @@ if ($arch eq "x86_64") { $ld .= " -m elf64_sparc"; $cc .= " -m64"; $objcopy .= " -O elf64-sparc"; +} elsif ($arch eq "microblaze") { + # Microblaze calls '_mcount' instead of plain 'mcount'. + $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$"; } else { die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD"; }