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authorJosh Poimboeuf <jpoimboe@redhat.com>2017-11-16 11:45:37 -0600
committerMichael Ellerman <mpe@ellerman.id.au>2017-12-11 13:03:29 +1100
commitb9eab08d012fa093947b230f9a87257c27fb829b (patch)
treefa5f33c519c97d9cbbf59b4598a8fdf8e8f4d273 /arch/powerpc/lib
parenta443bf6e8a7674b86221f4922cae82d67dc9e8ad (diff)
downloadtalos-obmc-linux-b9eab08d012fa093947b230f9a87257c27fb829b.tar.gz
talos-obmc-linux-b9eab08d012fa093947b230f9a87257c27fb829b.zip
powerpc/modules: Don't try to restore r2 after a sibling call
When attempting to load a livepatch module, I got the following error: module_64: patch_module: Expect noop after relocate, got 3c820000 The error was triggered by the following code in unregister_netdevice_queue(): 14c: 00 00 00 48 b 14c <unregister_netdevice_queue+0x14c> 14c: R_PPC64_REL24 net_set_todo 150: 00 00 82 3c addis r4,r2,0 GCC didn't insert a nop after the branch to net_set_todo() because it's a sibling call, so it never returns. The nop isn't needed after the branch in that case. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Reviewed-and-tested-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/lib')
-rw-r--r--arch/powerpc/lib/code-patching.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index d469224c4ada..096d4e4d31e6 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -302,6 +302,11 @@ int instr_is_relative_branch(unsigned int instr)
return instr_is_branch_iform(instr) || instr_is_branch_bform(instr);
}
+int instr_is_relative_link_branch(unsigned int instr)
+{
+ return instr_is_relative_branch(instr) && (instr & BRANCH_SET_LINK);
+}
+
static unsigned long branch_iform_target(const unsigned int *instr)
{
signed long imm;
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