From ac5f89c7d87f6f2fb7073723fc943488d9c3479d Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 29 Jun 2011 19:16:59 +0000 Subject: powerpc: Add jump label support This patch adds support for the new "jump label" feature. Unlike x86 and sparc we just merrily patch the code with no locks etc, as far as I know this is safe, but I'm not really sure what the x86/sparc code is protecting against so maybe it's not. I also don't see any reason for us to implement the poke_early() routine, even though sparc does. [BenH: Updated the patch to upstream generic changes] Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/jump_label.h | 47 +++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 arch/powerpc/include/asm/jump_label.h (limited to 'arch/powerpc/include/asm/jump_label.h') diff --git a/arch/powerpc/include/asm/jump_label.h b/arch/powerpc/include/asm/jump_label.h new file mode 100644 index 00000000000..1f780b95c0f --- /dev/null +++ b/arch/powerpc/include/asm/jump_label.h @@ -0,0 +1,47 @@ +#ifndef _ASM_POWERPC_JUMP_LABEL_H +#define _ASM_POWERPC_JUMP_LABEL_H + +/* + * Copyright 2010 Michael Ellerman, IBM Corp. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include + +#include + +#define JUMP_ENTRY_TYPE stringify_in_c(FTR_ENTRY_LONG) +#define JUMP_LABEL_NOP_SIZE 4 + +static __always_inline bool arch_static_branch(struct jump_label_key *key) +{ + asm goto("1:\n\t" + "nop\n\t" + ".pushsection __jump_table, \"aw\"\n\t" + ".align 4\n\t" + JUMP_ENTRY_TYPE "1b, %l[l_yes], %c0\n\t" + ".popsection \n\t" + : : "i" (key) : : l_yes); + return false; +l_yes: + return true; +} + +#ifdef CONFIG_PPC64 +typedef u64 jump_label_t; +#else +typedef u32 jump_label_t; +#endif + +struct jump_entry { + jump_label_t code; + jump_label_t target; + jump_label_t key; + jump_label_t pad; +}; + +#endif /* _ASM_POWERPC_JUMP_LABEL_H */ -- cgit v1.2.3-70-g09d2