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Subject[tip: x86/core] objtool: Correctly handle retpoline thunk calls
The following commit has been merged into the x86/core branch of tip:

Commit-ID: bcb1b6ff39da7e8a6a986eb08126fba2b5e13c32
Gitweb: https://git.kernel.org/tip/bcb1b6ff39da7e8a6a986eb08126fba2b5e13c32
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Fri, 26 Mar 2021 16:12:03 +01:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Fri, 02 Apr 2021 12:42:54 +02:00

objtool: Correctly handle retpoline thunk calls

Just like JMP handling, convert a direct CALL to a retpoline thunk
into a retpoline safe indirect CALL.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/20210326151259.567568238@infradead.org
---
tools/objtool/check.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index d45f018..519af4b 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1025,6 +1025,18 @@ static int add_call_destinations(struct objtool_file *file)
dest_off);
return -1;
}
+
+ } else if (!strncmp(reloc->sym->name, "__x86_indirect_thunk_", 21)) {
+ /*
+ * Retpoline calls are really dynamic calls in
+ * disguise, so convert them accordingly.
+ */
+ insn->type = INSN_CALL_DYNAMIC;
+ insn->retpoline_safe = true;
+
+ remove_insn_ops(insn);
+ continue;
+
} else
insn->call_dest = reloc->sym;

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