powerpc/ftrace: Use patch_instruction instead of probe_kernel_write()

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>

1 files changed, 4 insertions, 13 deletions

diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index d56848afd2cf..6f33296a0570 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 */