Re: [PATCH] jump label: Add MIPS support.

David Daney
2010-10-04T17:43:09Z

On 10/03/2010 11:15 AM, Rabin Vincent wrote:
> On Tue, Sep 28, 2010 at 11:40 PM, David Daney<ddaney@caviumnetworks.com> wrote:
>> +void arch_jump_label_text_poke_early(jump_label_t addr)
>> +{
>> + union mips_instruction *insn_p =
>> + (union mips_instruction *)(unsigned long)addr;
>> +
>> + insn_p->word = 0; /* nop */
>> + flush_icache_range((unsigned long)insn_p,
>> + (unsigned long)insn_p + sizeof(*insn_p));
>> +}
>
> Can't this function be a no-op on MIPS? This seems to be
> used on x86 to patch in the optimal nop instruction, but
> on MIPS the optimal/only nop instruction should already
> be in place at build time. Same thing for the SPARC
> implementation.
>

Yes, I think you are correct.

On MIPS the NOP is already optimal. I will respin the MIPS patch to
make arch_jump_label_text_poke_early() be empty.

davem wasn't CCed on the original message, so I added him. I would
defer to him on the SPARC version.

Thanks,
David Daney