[Xen-devel] [PATCH RFC V4 07/10] s390/jump-label: add arch_jump_label_transform_static()

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

From: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>

This allows jump-label entries to be cheaply updated on code which is
not yet live.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
Acked-by: Jason Baron <jbaron@xxxxxxxxxx>
Cc: Jan Glauber <jang@xxxxxxxxxxxxxxxxxx>
---
 arch/s390/kernel/jump_label.c |   51 +++++++++++++++++++++++++----------------
 1 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/arch/s390/kernel/jump_label.c b/arch/s390/kernel/jump_label.c
index 44cc06b..b987ab2 100644
--- a/arch/s390/kernel/jump_label.c
+++ b/arch/s390/kernel/jump_label.c
@@ -18,26 +18,15 @@ struct insn {
 } __packed;
 
 struct insn_args {
-       unsigned long *target;
-       struct insn *insn;
-       ssize_t size;
+       struct jump_entry *entry;
+       enum jump_label_type type;
 };
 
-static int __arch_jump_label_transform(void *data)
+static void __jump_label_transform(struct jump_entry *entry,
+                                  enum jump_label_type type)
 {
-       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;
+       int rc;
 
        if (type == JUMP_LABEL_ENABLE) {
                /* brcl 15,offset */
@@ -49,11 +38,33 @@ void arch_jump_label_transform(struct jump_entry *entry,
                insn.offset = 0;
        }
 
-       args.target = (void *) entry->code;
-       args.insn = &insn;
-       args.size = JUMP_LABEL_NOP_SIZE;
+       rc = probe_kernel_write((void *)entry->code, &insn, 
JUMP_LABEL_NOP_SIZE);
+       WARN_ON_ONCE(rc < 0);
+}
 
-       stop_machine(__arch_jump_label_transform, &args, NULL);
+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
-- 
1.7.6.4


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