From b9eab08d012fa093947b230f9a87257c27fb829b Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 16 Nov 2017 11:45:37 -0600 Subject: 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 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 Acked-by: Naveen N. Rao Reviewed-and-tested-by: Kamalesh Babulal Signed-off-by: Michael Ellerman --- arch/powerpc/lib/code-patching.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/powerpc/lib') 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; -- cgit v1.2.3