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[S390] ftrace: add dynamic ftrace support
Dynamic ftrace support for s390. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Heiko Carstens
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Martin Schwidefsky
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Jun 12, 2009
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,132 @@ | ||
| /* | ||
| * Dynamic function tracer architecture backend. | ||
| * | ||
| * Copyright IBM Corp. 2009 | ||
| * | ||
| * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>, | ||
| * | ||
| */ | ||
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| #include <linux/uaccess.h> | ||
| #include <linux/ftrace.h> | ||
| #include <linux/kernel.h> | ||
| #include <linux/types.h> | ||
| #include <asm/lowcore.h> | ||
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| void ftrace_disable_code(void); | ||
| void ftrace_call_code(void); | ||
| void ftrace_nop_code(void); | ||
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| #define FTRACE_INSN_SIZE 4 | ||
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| #ifdef CONFIG_64BIT | ||
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| asm( | ||
| " .align 4\n" | ||
| "ftrace_disable_code:\n" | ||
| " j 0f\n" | ||
| " .word 0x0024\n" | ||
| " lg %r1,"__stringify(__LC_FTRACE_FUNC)"\n" | ||
| " basr %r14,%r1\n" | ||
| " lg %r14,8(15)\n" | ||
| " lgr %r0,%r0\n" | ||
| "0:\n"); | ||
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| asm( | ||
| " .align 4\n" | ||
| "ftrace_nop_code:\n" | ||
| " j .+"__stringify(MCOUNT_INSN_SIZE)"\n"); | ||
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| asm( | ||
| " .align 4\n" | ||
| "ftrace_call_code:\n" | ||
| " stg %r14,8(%r15)\n"); | ||
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| #else /* CONFIG_64BIT */ | ||
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| asm( | ||
| " .align 4\n" | ||
| "ftrace_disable_code:\n" | ||
| " j 0f\n" | ||
| " l %r1,"__stringify(__LC_FTRACE_FUNC)"\n" | ||
| " basr %r14,%r1\n" | ||
| " l %r14,4(%r15)\n" | ||
| " j 0f\n" | ||
| " bcr 0,%r7\n" | ||
| " bcr 0,%r7\n" | ||
| " bcr 0,%r7\n" | ||
| " bcr 0,%r7\n" | ||
| " bcr 0,%r7\n" | ||
| " bcr 0,%r7\n" | ||
| "0:\n"); | ||
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| asm( | ||
| " .align 4\n" | ||
| "ftrace_nop_code:\n" | ||
| " j .+"__stringify(MCOUNT_INSN_SIZE)"\n"); | ||
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| asm( | ||
| " .align 4\n" | ||
| "ftrace_call_code:\n" | ||
| " st %r14,4(%r15)\n"); | ||
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| #endif /* CONFIG_64BIT */ | ||
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| static int ftrace_modify_code(unsigned long ip, | ||
| void *old_code, int old_size, | ||
| void *new_code, int new_size) | ||
| { | ||
| unsigned char replaced[MCOUNT_INSN_SIZE]; | ||
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| /* | ||
| * Note: Due to modules 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. | ||
| * This however is just a simple sanity check. | ||
| */ | ||
| if (probe_kernel_read(replaced, (void *)ip, old_size)) | ||
| return -EFAULT; | ||
| if (memcmp(replaced, old_code, old_size) != 0) | ||
| return -EINVAL; | ||
| if (probe_kernel_write((void *)ip, new_code, new_size)) | ||
| return -EPERM; | ||
| return 0; | ||
| } | ||
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| static int ftrace_make_initial_nop(struct module *mod, struct dyn_ftrace *rec, | ||
| unsigned long addr) | ||
| { | ||
| return ftrace_modify_code(rec->ip, | ||
| ftrace_call_code, FTRACE_INSN_SIZE, | ||
| ftrace_disable_code, MCOUNT_INSN_SIZE); | ||
| } | ||
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| int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, | ||
| unsigned long addr) | ||
| { | ||
| if (addr == MCOUNT_ADDR) | ||
| return ftrace_make_initial_nop(mod, rec, addr); | ||
| return ftrace_modify_code(rec->ip, | ||
| ftrace_call_code, FTRACE_INSN_SIZE, | ||
| ftrace_nop_code, FTRACE_INSN_SIZE); | ||
| } | ||
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| int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) | ||
| { | ||
| return ftrace_modify_code(rec->ip, | ||
| ftrace_nop_code, FTRACE_INSN_SIZE, | ||
| ftrace_call_code, FTRACE_INSN_SIZE); | ||
| } | ||
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| int ftrace_update_ftrace_func(ftrace_func_t func) | ||
| { | ||
| ftrace_dyn_func = (unsigned long)func; | ||
| return 0; | ||
| } | ||
|
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| int __init ftrace_dyn_arch_init(void *data) | ||
| { | ||
| *(unsigned long *)data = 0; | ||
| return 0; | ||
| } |
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