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Subject[PATCH 3/3][RFC] ftrace/ppc: Use patch_instruction instead of probe_kernel_write()
From: Steven Rostedt <srostedt@redhat.com>

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>
---
arch/powerpc/kernel/ftrace.c | 17 ++++-------------
1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 84a5ddd..4e376bc 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -63,11 +63,9 @@ ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new)
return -EINVAL;

/* 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;

- flush_icache_range(ip, ip + 8);
-
return 0;
}

@@ -212,12 +210,9 @@ __ftrace_make_nop(struct module *mod,
*/
op = 0x48000008; /* b +8 */

- if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
+ if (patch_instruction((unsigned int *)ip, op))
return -EPERM;

-
- flush_icache_range(ip, ip + 8);
-
return 0;
}

@@ -286,11 +281,9 @@ __ftrace_make_nop(struct module *mod,

op = PPC_INST_NOP;

- if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
+ if (patch_instruction((unsigned int *)ip, op))
return -EPERM;

- flush_icache_range(ip, ip + 8);
-
return 0;
}
#endif /* PPC64 */
@@ -426,11 +419,9 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)

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;

- flush_icache_range(ip, ip + 8);
-
return 0;
}
#endif /* CONFIG_PPC64 */
--
1.7.9.5



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