x86/kvm: Move kvm_fastop_exception to .fixup section

jpoimboe · rkrcmar · commit f26e60167d8b · 2017-10-05T15:06:30.000+02:00
When compiling the kernel with the '-frecord-gcc-switches' flag, objtool
complains:

  arch/x86/kvm/emulate.o: warning: objtool: .GCC.command.line+0x0: special: can't find new instruction

And also the kernel fails to link.

The problem is that the 'kvm_fastop_exception' code gets placed into the
throwaway '.GCC.command.line' section instead of '.text'.

Exception fixup code is conventionally placed in the '.fixup' section,
so put it there where it belongs.

Reported-and-tested-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Reviewed-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Signed-off-by: Radim Krčmář &lt;rkrcmar@redhat.com&gt;
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
@@ -425,8 +425,10 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *));
 	#op " %al \n\t" \
 	FOP_RET
 
-asm(".global kvm_fastop_exception \n"
-    "kvm_fastop_exception: xor %esi, %esi; ret");
+asm(".pushsection .fixup, \"ax\"\n"
+    ".global kvm_fastop_exception \n"
+    "kvm_fastop_exception: xor %esi, %esi; ret\n"
+    ".popsection");
 
 FOP_START(setcc)
 FOP_SETCC(seto)
