Commit dfc382a1 authored by Michael Ellerman's avatar Michael Ellerman Committed by Benjamin Herrenschmidt
Browse files

powerpc/ftrace: Fix typo in mask of opcode

In commit 24a1bdc3

, "Fix ABIv2 issues with __ftrace_make_call", Anton
changed the logic that checks for the expected code sequence when
patching a module.

We missed the typo in the mask, 0xffff00000 should be 0xffff0000, which
has the effect of making the test always true.

That makes it impossible to ftrace against modules, eg:

  Unexpected call sequence: 48000008 e8410018
  WARNING: at ../kernel/trace/ftrace.c:1638
  ftrace failed to modify [<d000000007cf001c>] rng_dev_open+0x1c/0x70 [rng_core]
Reported-by: default avatarDavid Binderman <dcb314@hotmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent d997c00c
......@@ -307,7 +307,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
* The load offset is different depending on the ABI. For simplicity
* just mask it out when doing the compare.
*/
if ((op[0] != 0x48000008) || ((op[1] & 0xffff00000) != 0xe8410000)) {
if ((op[0] != 0x48000008) || ((op[1] & 0xffff0000) != 0xe8410000)) {
printk(KERN_ERR "Unexpected call sequence: %x %x\n",
op[0], op[1]);
return -EINVAL;
......
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