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

To: Rabin Vincent <rabin@rab.in>
Subject: Re: [PATCH] jump label: Add MIPS support.
From: David Daney <ddaney@caviumnetworks.com>
Date: Mon, 04 Oct 2010 10:43:07 -0700
Cc: linux-mips@linux-mips.org, ralf@linux-mips.org, linux-kernel@vger.kernel.org, rostedt@goodmis.org, jbaron@redhat.com, David Miller <davem@davemloft.net>
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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

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