uprobes: Document xol_area and arch_uprobe->insn/ixol
Document xol_area and arch_uprobe.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 51a7f53..b886a5e 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -73,6 +73,17 @@
struct inode *inode; /* Also hold a ref to inode */
loff_t offset;
unsigned long flags;
+
+ /*
+ * The generic code assumes that it has two members of unknown type
+ * owned by the arch-specific code:
+ *
+ * insn - copy_insn() saves the original instruction here for
+ * arch_uprobe_analyze_insn().
+ *
+ * ixol - potentially modified instruction to execute out of
+ * line, copied to xol_area by xol_get_insn_slot().
+ */
struct arch_uprobe arch;
};
@@ -86,6 +97,10 @@
};
/*
+ * Execute out of line area: anonymous executable mapping installed
+ * by the probed task to execute the copy of the original instruction
+ * mangled by set_swbp().
+ *
* On a breakpoint hit, thread contests for a slot. It frees the
* slot after singlestep. Currently a fixed number of slots are
* allocated.
