diff options
| -rw-r--r-- | arch/s390/Kconfig | 1 | ||||
| -rw-r--r-- | arch/s390/include/asm/jump_label.h | 37 | ||||
| -rw-r--r-- | arch/s390/kernel/Makefile | 2 | ||||
| -rw-r--r-- | arch/s390/kernel/jump_label.c | 59 |
4 files changed, 98 insertions, 1 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 2508a6f3158..4a7f14079e0 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -88,6 +88,7 @@ config S390 select HAVE_KERNEL_XZ select HAVE_GET_USER_PAGES_FAST select HAVE_ARCH_MUTEX_CPU_RELAX + select HAVE_ARCH_JUMP_LABEL if !MARCH_G5 select ARCH_INLINE_SPIN_TRYLOCK select ARCH_INLINE_SPIN_TRYLOCK_BH select ARCH_INLINE_SPIN_LOCK 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 diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile index 64230bc392f..5ff15dacb57 100644 --- a/arch/s390/kernel/Makefile +++ b/arch/s390/kernel/Makefile @@ -23,7 +23,7 @@ CFLAGS_sysinfo.o += -Iinclude/math-emu -Iarch/s390/math-emu -w obj-y := bitmap.o traps.o time.o process.o base.o early.o setup.o \ processor.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o \ s390_ext.o debug.o irq.o ipl.o dis.o diag.o mem_detect.o \ - vdso.o vtime.o sysinfo.o nmi.o sclp.o + vdso.o vtime.o sysinfo.o nmi.o sclp.o jump_label.o obj-y += $(if $(CONFIG_64BIT),entry64.o,entry.o) obj-y += $(if $(CONFIG_64BIT),reipl64.o,reipl.o) diff --git a/arch/s390/kernel/jump_label.c b/arch/s390/kernel/jump_label.c new file mode 100644 index 00000000000..44cc06bedf7 --- /dev/null +++ b/arch/s390/kernel/jump_label.c @@ -0,0 +1,59 @@ +/* + * Jump label s390 support + * + * Copyright IBM Corp. 2011 + * Author(s): Jan Glauber <jang@linux.vnet.ibm.com> + */ +#include <linux/module.h> +#include <linux/uaccess.h> +#include <linux/stop_machine.h> +#include <linux/jump_label.h> +#include <asm/ipl.h> + +#ifdef HAVE_JUMP_LABEL + +struct insn { + u16 opcode; + s32 offset; +} __packed; + +struct insn_args { + unsigned long *target; + struct insn *insn; + ssize_t size; +}; + +static int __arch_jump_label_transform(void *data) +{ + struct insn_args *args = data; + int rc; + + rc = probe_kernel_write(args->target, args->insn, args->size); + WARN_ON_ONCE(rc < 0); + return 0; +} + +void arch_jump_label_transform(struct jump_entry *entry, + enum jump_label_type type) +{ + struct insn_args args; + struct insn insn; + + if (type == JUMP_LABEL_ENABLE) { + /* brcl 15,offset */ + insn.opcode = 0xc0f4; + insn.offset = (entry->target - entry->code) >> 1; + } else { + /* brcl 0,0 */ + insn.opcode = 0xc004; + insn.offset = 0; + } + + args.target = (void *) entry->code; + args.insn = &insn; + args.size = JUMP_LABEL_NOP_SIZE; + + stop_machine(__arch_jump_label_transform, &args, NULL); +} + +#endif |