On 04/10/2017 17:39, Josh Poimboeuf wrote:
> 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 <linux@xxxxxxxxxxxx>
> Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> ---
> arch/x86/kvm/emulate.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index a36254cbf776..d90cdc77e077 100644
> --- 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)
>
Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
