From 5373db886b791b2bc7811e2c115377916c409a5d Mon Sep 17 00:00:00 2001 From: Jan Glauber Date: Wed, 16 Mar 2011 15:58:30 -0400 Subject: jump label: Add s390 support Implement the architecture backend for jump label support on s390. For a shared kernel booted from a NSS silently disable jump labels because the NSS is read-only. Therefore jump labels will be disabled in a shared kernel and can't be activated. Signed-off-by: Jan Glauber LKML-Reference: <6935d2c41ce111e1719176ed4bbd3dbe4de80855.1300299760.git.jbaron@redhat.com> Acked-by: Peter Zijlstra Signed-off-by: Martin Schwidefsky Signed-off-by: Steven Rostedt --- arch/s390/include/asm/jump_label.h | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 arch/s390/include/asm/jump_label.h (limited to 'arch/s390/include/asm') diff --git a/arch/s390/include/asm/jump_label.h b/arch/s390/include/asm/jump_label.h new file mode 100644 index 000000000000..95a6cf2b5b67 --- /dev/null +++ b/arch/s390/include/asm/jump_label.h @@ -0,0 +1,37 @@ +#ifndef _ASM_S390_JUMP_LABEL_H +#define _ASM_S390_JUMP_LABEL_H + +#include + +#define JUMP_LABEL_NOP_SIZE 6 + +#ifdef CONFIG_64BIT +#define ASM_PTR ".quad" +#define ASM_ALIGN ".balign 8" +#else +#define ASM_PTR ".long" +#define ASM_ALIGN ".balign 4" +#endif + +static __always_inline bool arch_static_branch(struct jump_label_key *key) +{ + asm goto("0: brcl 0,0\n" + ".pushsection __jump_table, \"aw\"\n" + ASM_ALIGN "\n" + ASM_PTR " 0b, %l[label], %0\n" + ".popsection\n" + : : "X" (key) : : label); + return false; +label: + return true; +} + +typedef unsigned long jump_label_t; + +struct jump_entry { + jump_label_t code; + jump_label_t target; + jump_label_t key; +}; + +#endif -- cgit v1.2.3