diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/sh/Kconfig | 2 | ||||
| -rw-r--r-- | arch/sh/include/asm/ftrace.h | 21 | ||||
| -rw-r--r-- | arch/sh/kernel/Makefile_32 | 6 | ||||
| -rw-r--r-- | arch/sh/kernel/entry-common.S | 44 | ||||
| -rw-r--r-- | arch/sh/kernel/ftrace.c | 109 | ||||
| -rw-r--r-- | arch/sh/lib/Makefile | 1 | ||||
| -rw-r--r-- | arch/sh/lib/mcount.S | 90 |
7 files changed, 229 insertions, 44 deletions
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index 5c9cbfc14c4..fd2c02d614b 100644 --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -25,6 +25,8 @@ config SUPERH32 select HAVE_KRETPROBES select HAVE_ARCH_TRACEHOOK select HAVE_FUNCTION_TRACER + select HAVE_FTRACE_MCOUNT_RECORD + select HAVE_DYNAMIC_FTRACE config SUPERH64 def_bool y if CPU_SH5 diff --git a/arch/sh/include/asm/ftrace.h b/arch/sh/include/asm/ftrace.h index 3aed362c946..4cb5dbfc404 100644 --- a/arch/sh/include/asm/ftrace.h +++ b/arch/sh/include/asm/ftrace.h @@ -1,8 +1,29 @@ #ifndef __ASM_SH_FTRACE_H #define __ASM_SH_FTRACE_H +#ifdef CONFIG_FUNCTION_TRACER + +#define MCOUNT_INSN_SIZE 4 /* sizeof mcount call */ + #ifndef __ASSEMBLY__ extern void mcount(void); + +#define MCOUNT_ADDR ((long)(mcount)) + +#ifdef CONFIG_DYNAMIC_FTRACE +#define CALLER_ADDR ((long)(ftrace_caller)) +#define STUB_ADDR ((long)(ftrace_stub)) + +#define MCOUNT_INSN_OFFSET ((STUB_ADDR - CALLER_ADDR) >> 1) +#endif + +static inline unsigned long ftrace_call_adjust(unsigned long addr) +{ + /* 'addr' is the memory table address. */ + return addr; +} #endif +#endif /* CONFIG_FUNCTION_TRACER */ + #endif /* __ASM_SH_FTRACE_H */ diff --git a/arch/sh/kernel/Makefile_32 b/arch/sh/kernel/Makefile_32 index 48edfb145fb..76fcac1596c 100644 --- a/arch/sh/kernel/Makefile_32 +++ b/arch/sh/kernel/Makefile_32 @@ -4,6 +4,11 @@ extra-y := head_32.o init_task.o vmlinux.lds +ifdef CONFIG_FUNCTION_TRACER +# Do not profile debug and lowlevel utilities +CFLAGS_REMOVE_ftrace.o = -pg +endif + obj-y := debugtraps.o io.o io_generic.o irq.o machvec.o process_32.o \ ptrace_32.o setup.o signal_32.o sys_sh.o sys_sh32.o \ syscalls_32.o time_32.o topology.o traps.o traps_32.o @@ -24,5 +29,6 @@ obj-$(CONFIG_STACKTRACE) += stacktrace.o obj-$(CONFIG_IO_TRAPPED) += io_trapped.o obj-$(CONFIG_KPROBES) += kprobes.o obj-$(CONFIG_GENERIC_GPIO) += gpio.o +obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o EXTRA_CFLAGS += -Werror diff --git a/arch/sh/kernel/entry-common.S b/arch/sh/kernel/entry-common.S index 5b7efc4016f..efbb4268875 100644 --- a/arch/sh/kernel/entry-common.S +++ b/arch/sh/kernel/entry-common.S @@ -371,47 +371,3 @@ syscall_exit: #endif 7: .long do_syscall_trace_enter 8: .long do_syscall_trace_leave - -#ifdef CONFIG_FUNCTION_TRACER - .align 2 - .globl _mcount - .type _mcount,@function - .globl mcount - .type mcount,@function -_mcount: -mcount: - mov.l r4, @-r15 - mov.l r5, @-r15 - mov.l r6, @-r15 - mov.l r7, @-r15 - sts.l pr, @-r15 - - mov.l @(20,r15),r4 - sts pr, r5 - - mov.l 1f, r6 - mov.l ftrace_stub, r7 - cmp/eq r6, r7 - bt skip_trace - - mov.l @r6, r6 - jsr @r6 - nop - -skip_trace: - - lds.l @r15+, pr - mov.l @r15+, r7 - mov.l @r15+, r6 - mov.l @r15+, r5 - rts - mov.l @r15+, r4 - - .align 2 -1: .long ftrace_trace_function - - .globl ftrace_stub -ftrace_stub: - rts - nop -#endif /* CONFIG_FUNCTION_TRACER */ diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c new file mode 100644 index 00000000000..6c193d56c2e --- /dev/null +++ b/arch/sh/kernel/ftrace.c @@ -0,0 +1,109 @@ +/* + * Copyright (C) 2008 Matt Fleming <mjf@gentoo.org> + * + * Code for replacing ftrace calls with jumps. + * + * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> + * + * Thanks goes to Ingo Molnar, for suggesting the idea. + * Mathieu Desnoyers, for suggesting postponing the modifications. + * Arjan van de Ven, for keeping me straight, and explaining to me + * the dangers of modifying code on the run. + */ +#include <linux/uaccess.h> +#include <linux/ftrace.h> +#include <linux/string.h> +#include <linux/init.h> +#include <linux/io.h> +#include <asm/ftrace.h> +#include <asm/cacheflush.h> + +static unsigned char ftrace_nop[] = { + 0x09, 0x00, /* nop */ + 0x09, 0x00, /* nop */ +}; + +static unsigned char ftrace_replaced_code[MCOUNT_INSN_SIZE]; + +unsigned char *ftrace_nop_replace(void) +{ + return ftrace_nop; +} + +static int is_sh_nop(unsigned char *ip) +{ + return strncmp(ip, ftrace_nop, sizeof(ftrace_nop)); +} + +unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr) +{ + /* Place the address in the memory table. */ + if (addr == CALLER_ADDR) + __raw_writel(addr + MCOUNT_INSN_OFFSET, ftrace_replaced_code); + else + __raw_writel(addr, ftrace_replaced_code); + + /* + * No locking needed, this must be called via kstop_machine + * which in essence is like running on a uniprocessor machine. + */ + return ftrace_replaced_code; +} + +int ftrace_modify_code(unsigned long ip, unsigned char *old_code, + unsigned char *new_code) +{ + unsigned char replaced[MCOUNT_INSN_SIZE]; + + /* + * Note: Due to modules and __init, code can + * disappear and change, we need to protect against faulting + * as well as code changing. We do this by using the + * probe_kernel_* functions. + * + * No real locking needed, this code is run through + * kstop_machine, or before SMP starts. + */ + + /* + * If we're trying to nop out a call to a function, we instead + * place a call to the address after the memory table. + */ + if (is_sh_nop(new_code) == 0) + __raw_writel(ip + MCOUNT_INSN_SIZE, (unsigned long)new_code); + + /* 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 (probe_kernel_write((void *)ip, new_code, MCOUNT_INSN_SIZE)) + return -EPERM; + + flush_icache_range(ip, ip + MCOUNT_INSN_SIZE); + + return 0; +} + +int ftrace_update_ftrace_func(ftrace_func_t func) +{ + unsigned long ip = (unsigned long)(&ftrace_call); + unsigned char old[MCOUNT_INSN_SIZE], *new; + + memcpy(old, (unsigned char *)(ip + MCOUNT_INSN_OFFSET), MCOUNT_INSN_SIZE); + new = ftrace_call_replace(ip, (unsigned long)func); + + return ftrace_modify_code(ip + MCOUNT_INSN_OFFSET, old, new); +} + +int __init ftrace_dyn_arch_init(void *data) +{ + /* The return code is retured via data */ + __raw_writel(0, (unsigned long)data); + + return 0; +} diff --git a/arch/sh/lib/Makefile b/arch/sh/lib/Makefile index 8596cc78e18..596421821d0 100644 --- a/arch/sh/lib/Makefile +++ b/arch/sh/lib/Makefile @@ -11,6 +11,7 @@ memcpy-y := memcpy.o memcpy-$(CONFIG_CPU_SH4) := memcpy-sh4.o lib-$(CONFIG_MMU) += copy_page.o clear_page.o +lib-$(CONFIG_FUNCTION_TRACER) += mcount.o lib-y += $(memcpy-y) EXTRA_CFLAGS += -Werror diff --git a/arch/sh/lib/mcount.S b/arch/sh/lib/mcount.S new file mode 100644 index 00000000000..110fbfe1831 --- /dev/null +++ b/arch/sh/lib/mcount.S @@ -0,0 +1,90 @@ +/* + * arch/sh/lib/mcount.S + * + * Copyright (C) 2008 Paul Mundt + * Copyright (C) 2008 Matt Fleming + * + * 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 <asm/ftrace.h> + +#define MCOUNT_ENTER() \ + mov.l r4, @-r15; \ + mov.l r5, @-r15; \ + mov.l r6, @-r15; \ + mov.l r7, @-r15; \ + sts.l pr, @-r15; \ + \ + mov.l @(20,r15),r4; \ + sts pr, r5 + +#define MCOUNT_LEAVE() \ + lds.l @r15+, pr; \ + mov.l @r15+, r7; \ + mov.l @r15+, r6; \ + mov.l @r15+, r5; \ + rts; \ + mov.l @r15+, r4 + + .align 2 + .globl _mcount + .type _mcount,@function + .globl mcount + .type mcount,@function +_mcount: +mcount: + MCOUNT_ENTER() + +#ifdef CONFIG_DYNAMIC_FTRACE + .globl mcount_call +mcount_call: + mov.l .Lftrace_stub, r6 +#else + mov.l .Lftrace_trace_function, r6 + mov.l ftrace_stub, r7 + cmp/eq r6, r7 + bt skip_trace + mov.l @r6, r6 +#endif + + jsr @r6 + nop + +skip_trace: + MCOUNT_LEAVE() + + .align 2 +.Lftrace_trace_function: + .long ftrace_trace_function + +#ifdef CONFIG_DYNAMIC_FTRACE + .globl ftrace_caller +ftrace_caller: + MCOUNT_ENTER() + + .globl ftrace_call +ftrace_call: + mov.l .Lftrace_stub, r6 + jsr @r6 + nop + + MCOUNT_LEAVE() +#endif /* CONFIG_DYNAMIC_FTRACE */ + +/* + * NOTE: From here on the locations of the .Lftrace_stub label and + * ftrace_stub itself are fixed. Adding additional data here will skew + * the displacement for the memory table and break the block replacement. + * Place new labels either after the ftrace_stub body, or before + * ftrace_caller. You have been warned. + */ + .align 2 +.Lftrace_stub: + .long ftrace_stub + + .globl ftrace_stub +ftrace_stub: + rts + nop |