On Thu, Feb 25, 2016 at 01:28:27AM +1100, Michael Ellerman wrote:
> @@ -450,17 +448,44 @@ static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs,
> return (unsigned long)&stubs[i];
> }
>
> +#ifdef CC_USING_MPROFILE_KERNEL
> +static int is_early_mcount_callsite(u32 *instruction)
> +{
> + /* -mprofile-kernel sequence starting with
> + * mflr r0 and maybe std r0, LRSAVE(r1).
> + */
> + if ((instruction[-3] == PPC_INST_MFLR &&
> + instruction[-2] == PPC_INST_STD_LR) ||
> + instruction[-2] == PPC_INST_MFLR) {
> + /* Nothing to be done here, it's an _mcount
> + * call location and r2 will have to be
> + * restored in the _mcount function.
> + */
> + return 1;
> + }
> + return 0;
> +}
> +#else
*You* said this might page fault :)
Did we agree yet whether we insist on a streamlined compiler?
(GCC commit e95d0248dace required)?
If not:
if (instruction[-2] == PPC_INST_STD_LR)
{
if (instruction[-3] == PPC_INST_MFLR)
return 1;
}
else if (instruction[-2] == PPC_INST_MFLR)
return 1;
return 0;
leaves less freedom for the compiler to "optimise".
Signed-off-by: Torsten Duwe <duwe@xxxxxxx>
Torsten
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