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powerpc/ftrace: Use patch_instruction instead of probe_kernel_write()

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The patch_instruction() interface is made to modify kernel text. It is
safer to use that then the probe_kernel_write() when modifying kernel
code.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Steven Rostedt 2012-04-26 08:31:19 +00:00 • committed by Benjamin Herrenschmidt
parent b6e3796834
commit 65b8c7226e
1 changed files with 4 additions and 13 deletions
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17
arch/powerpc/kernel/ftrace.c
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@ -63,11 +63,9 @@ ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new)
return -EINVAL; return -EINVAL;
/* replace the text with the new text */ /* replace the text with the new text */
if (probe_kernel_write((void *)ip, &new, MCOUNT_INSN_SIZE)) if (patch_instruction((unsigned int *)ip, new))
return -EPERM; return -EPERM;
flush_icache_range(ip, ip + 8);
return 0; return 0;
} }
@ -212,12 +210,9 @@ __ftrace_make_nop(struct module *mod,
*/ */
op = 0x48000008; /* b +8 */ op = 0x48000008; /* b +8 */
if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE)) if (patch_instruction((unsigned int *)ip, op))
return -EPERM; return -EPERM;
flush_icache_range(ip, ip + 8);
return 0; return 0;
} }
@ -286,11 +281,9 @@ __ftrace_make_nop(struct module *mod,
op = PPC_INST_NOP; op = PPC_INST_NOP;
if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE)) if (patch_instruction((unsigned int *)ip, op))
return -EPERM; return -EPERM;
flush_icache_range(ip, ip + 8);
return 0; return 0;
} }
#endif /* PPC64 */ #endif /* PPC64 */
@ -426,11 +419,9 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
pr_devel("write to %lx\n", rec->ip); pr_devel("write to %lx\n", rec->ip);
if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE)) if (patch_instruction((unsigned int *)ip, op))
return -EPERM; return -EPERM;
flush_icache_range(ip, ip + 8);
return 0; return 0;
} }
#endif /* CONFIG_PPC64 */ #endif /* CONFIG_PPC64 */