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Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/ftrace.c55
1 files changed, 27 insertions, 28 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index e625319..52819e8 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -308,7 +308,10 @@ static int ftrace_write(unsigned long ip, const char *val, int size)
if (within(ip, (unsigned long)_text, (unsigned long)_etext))
ip = (unsigned long)__va(__pa_symbol(ip));
- return probe_kernel_write((void *)ip, val, size);
+ if (probe_kernel_write((void *)ip, val, size))
+ return -EPERM;
+
+ return 0;
}
static int add_break(unsigned long ip, const char *old)
@@ -323,10 +326,7 @@ static int add_break(unsigned long ip, const char *old)
if (memcmp(replaced, old, MCOUNT_INSN_SIZE) != 0)
return -EINVAL;
- if (ftrace_write(ip, &brk, 1))
- return -EPERM;
-
- return 0;
+ return ftrace_write(ip, &brk, 1);
}
static int add_brk_on_call(struct dyn_ftrace *rec, unsigned long addr)
@@ -425,7 +425,7 @@ static int remove_breakpoint(struct dyn_ftrace *rec)
/* If this does not have a breakpoint, we are done */
if (ins[0] != brk)
- return -1;
+ return 0;
nop = ftrace_nop_replace();
@@ -455,7 +455,7 @@ static int remove_breakpoint(struct dyn_ftrace *rec)
}
update:
- return probe_kernel_write((void *)ip, &nop[0], 1);
+ return ftrace_write(ip, nop, 1);
}
static int add_update_code(unsigned long ip, unsigned const char *new)
@@ -463,9 +463,7 @@ static int add_update_code(unsigned long ip, unsigned const char *new)
/* skip breakpoint */
ip++;
new++;
- if (ftrace_write(ip, new, MCOUNT_INSN_SIZE - 1))
- return -EPERM;
- return 0;
+ return ftrace_write(ip, new, MCOUNT_INSN_SIZE - 1);
}
static int add_update_call(struct dyn_ftrace *rec, unsigned long addr)
@@ -520,10 +518,7 @@ static int finish_update_call(struct dyn_ftrace *rec, unsigned long addr)
new = ftrace_call_replace(ip, addr);
- if (ftrace_write(ip, new, 1))
- return -EPERM;
-
- return 0;
+ return ftrace_write(ip, new, 1);
}
static int finish_update_nop(struct dyn_ftrace *rec)
@@ -533,9 +528,7 @@ static int finish_update_nop(struct dyn_ftrace *rec)
new = ftrace_nop_replace();
- if (ftrace_write(ip, new, 1))
- return -EPERM;
- return 0;
+ return ftrace_write(ip, new, 1);
}
static int finish_update(struct dyn_ftrace *rec, int enable)
@@ -632,8 +625,14 @@ void ftrace_replace_code(int enable)
printk(KERN_WARNING "Failed on %s (%d):\n", report, count);
for_ftrace_rec_iter(iter) {
rec = ftrace_rec_iter_record(iter);
- remove_breakpoint(rec);
+ /*
+ * Breakpoints are handled only when this function is in
+ * progress. The system could not work with them.
+ */
+ if (remove_breakpoint(rec))
+ BUG();
}
+ run_sync();
}
static int
@@ -655,16 +654,19 @@ ftrace_modify_code(unsigned long ip, unsigned const char *old_code,
run_sync();
ret = ftrace_write(ip, new_code, 1);
- if (ret) {
- ret = -EPERM;
- goto out;
- }
- run_sync();
+ /*
+ * The breakpoint is handled only when this function is in progress.
+ * The system could not work if we could not remove it.
+ */
+ BUG_ON(ret);
out:
+ run_sync();
return ret;
fail_update:
- probe_kernel_write((void *)ip, &old_code[0], 1);
+ /* Also here the system could not work with the breakpoint */
+ if (ftrace_write(ip, old_code, 1))
+ BUG();
goto out;
}
@@ -678,11 +680,8 @@ void arch_ftrace_update_code(int command)
atomic_dec(&modifying_ftrace_code);
}
-int __init ftrace_dyn_arch_init(void *data)
+int __init ftrace_dyn_arch_init(void)
{
- /* The return code is retured via data */
- *(unsigned long *)data = 0;
-
return 0;
}
#endif