diff options
| author | Jan Glauber <jang@linux.vnet.ibm.com> | 2011-03-16 15:58:30 -0400 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2011-04-04 13:43:16 -0400 |
| commit | 5373db886b791b2bc7811e2c115377916c409a5d (patch) | |
| tree | 1653948d7260448ff87b7858bd2f6ec331995ce4 /arch/s390/include/asm | |
| parent | ef64789413c73f32faa5e5f1bc393e5843b0aa51 (diff) | |
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 <jang@linux.vnet.ibm.com>
LKML-Reference: <6935d2c41ce111e1719176ed4bbd3dbe4de80855.1300299760.git.jbaron@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'arch/s390/include/asm')
| -rw-r--r-- | arch/s390/include/asm/jump_label.h | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/arch/s390/include/asm/jump_label.h b/arch/s390/include/asm/jump_label.h new file mode 100644 index 00000000000..95a6cf2b5b6 --- /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 <linux/types.h> + +#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 |