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powerpc/ftrace: Fix nop of modules on 64bit LE (ABIv2) 

There is a bug in the handling of the function entry when we are nopping
out a branch from a module in ftrace.

We compare the result of module_trampoline_target() with the value of
ppc_function_entry(), and expect them to be true. But they never will
be.

module_trampoline_target() will always return the global entry point of
the function, whereas ppc_function_entry() will always return the local.

Fix it by using the newly added ppc_global_function_entry().

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Michael Ellerman 2014-06-17 16:15:35 +10:00 committed by Benjamin Herrenschmidt
parent b7b348c682
commit d84e0d69c2
1 changed files with 4 additions and 3 deletions
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7
arch/powerpc/kernel/ftrace.c
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@ -105,7 +105,7 @@ __ftrace_make_nop(struct module *mod,
struct dyn_ftrace *rec, unsigned long addr)
{
unsigned int op;
unsigned long ptr;
unsigned long entry, ptr;
unsigned long ip = rec->ip;
void *tramp;
@ -136,10 +136,11 @@ __ftrace_make_nop(struct module *mod,
pr_devel("trampoline target %lx", ptr);
entry = ppc_global_function_entry((void *)addr);
/* This should match what was called */
if (ptr != ppc_function_entry((void *)addr)) {
if (ptr != entry) {
printk(KERN_ERR "addr %lx does not match expected %lx\n",
ptr, ppc_function_entry((void *)addr));
ptr, entry);
return -EINVAL;
}