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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2008-12-28 22:39:19 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-12-28 22:39:19 +0300 |
| commit | 81d6e59dabb1ae0c782e9eb7e3d88f699d25b314 (patch) | |
| tree | 532afd14c119f1c95206ef0d23db9c4c26a0aa34 /arch/sh/kernel/ftrace.c | |
| parent | 4a6908a3a050aacc9c3a2f36b276b46c0629ad91 (diff) | |
| parent | 59de580af1c2fd671b0cb27c41ff958859ae5288 (diff) | |
| download | linux-81d6e59dabb1ae0c782e9eb7e3d88f699d25b314.tar.xz | |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: (132 commits)
sh: oprofile: Fix up the module build.
sh: add UIO support for JPU on SH7722.
serial: sh-sci: Fix up port pinmux for SH7366.
sh: mach-rsk: Use uImage generation by default for rsk7201/7203.
sh: mach-sh03: Fix up pata_platform build breakage.
sh: enable deferred io LCDC on Migo-R
video: sh_mobile_lcdcfb deferred io support
video: deferred io with physically contiguous memory
video: deferred io cleanup
video: fix deferred io fsync()
sh: add LCDC interrupt configuration to AP325 and Migo-R
sh_mobile_lcdc: use FB_SYS helpers instead of FB_CFB
sh: split coherent pages
sh: dma: Kill off ISA DMA wrapper.
sh: Conditionalize the code dumper on CONFIG_DUMP_CODE.
sh: Kill off the unused SH_ALPHANUMERIC debug option.
sh: Enable skipping of bss on debug platforms for sh32 also.
doc: Update sh cpufreq documentation.
sh: mrshpc_setup_windows() needs to be inline.
serial: sh-sci: sci_poll_get_char() is only used by CONFIG_CONSOLE_POLL.
...
Diffstat (limited to 'arch/sh/kernel/ftrace.c')
| -rw-r--r-- | arch/sh/kernel/ftrace.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c new file mode 100644 index 000000000000..4c3247477aa3 --- /dev/null +++ b/arch/sh/kernel/ftrace.c @@ -0,0 +1,133 @@ +/* + * Copyright (C) 2008 Matt Fleming <mjf@gentoo.org> + * Copyright (C) 2008 Paul Mundt <lethal@linux-sh.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 ftrace_make_nop(struct module *mod, + struct dyn_ftrace *rec, unsigned long addr) +{ + unsigned char *new, *old; + unsigned long ip = rec->ip; + + old = ftrace_call_replace(ip, 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; + unsigned long ip = rec->ip; + + old = ftrace_nop_replace(); + new = ftrace_call_replace(ip, addr); + + return ftrace_modify_code(rec->ip, 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; +} |
