Commit d84e0d69 authored Jun 17, 2014 by Michael Ellerman Committed by Benjamin Herrenschmidt Jun 24, 2014

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>

parent b7b348c6

arch/powerpc/kernel/ftrace.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -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;
		}

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