From 8e4bff4cab0ddac6060645b0715210484d02ff40 Mon Sep 17 00:00:00 2001 From: Yuval Adam <_@yuv.al> Date: Wed, 30 Aug 2017 08:25:59 +0000 Subject: Initial file dump from open source release --- arch/s390/kernel/jump_label.c | 70 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 arch/s390/kernel/jump_label.c (limited to 'arch/s390/kernel/jump_label.c') diff --git a/arch/s390/kernel/jump_label.c b/arch/s390/kernel/jump_label.c new file mode 100644 index 00000000..b987ab2c --- /dev/null +++ b/arch/s390/kernel/jump_label.c @@ -0,0 +1,70 @@ +/* + * Jump label s390 support + * + * Copyright IBM Corp. 2011 + * Author(s): Jan Glauber + */ +#include +#include +#include +#include +#include + +#ifdef HAVE_JUMP_LABEL + +struct insn { + u16 opcode; + s32 offset; +} __packed; + +struct insn_args { + struct jump_entry *entry; + enum jump_label_type type; +}; + +static void __jump_label_transform(struct jump_entry *entry, + enum jump_label_type type) +{ + struct insn insn; + int rc; + + 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; + } + + rc = probe_kernel_write((void *)entry->code, &insn, JUMP_LABEL_NOP_SIZE); + WARN_ON_ONCE(rc < 0); +} + +static int __sm_arch_jump_label_transform(void *data) +{ + struct insn_args *args = data; + + __jump_label_transform(args->entry, args->type); + return 0; +} + +void arch_jump_label_transform(struct jump_entry *entry, + enum jump_label_type type) +{ + struct insn_args args; + + args.entry = entry; + args.type = type; + + stop_machine(__sm_arch_jump_label_transform, &args, NULL); +} + +void arch_jump_label_transform_static(struct jump_entry *entry, + enum jump_label_type type) +{ + __jump_label_transform(entry, type); +} + +#endif -- cgit v1.3.1