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authorOleg Nesterov <oleg@redhat.com>2013-11-19 17:20:21 +0100
committerOleg Nesterov <oleg@redhat.com>2013-11-20 16:31:07 +0100
commitad439356ae5ae7688b39f1107fd5b874850fec18 (patch)
tree68bf1b6af1bbcf0d800cee2e011227a75a01149e
parentc912dae60ae6f659455f239298110adc67a5f3e9 (diff)
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>
-rw-r--r--kernel/events/uprobes.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 51a7f535ff96..b886a5e7d4ff 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -73,6 +73,17 @@ struct uprobe {
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 @@ struct return_instance {
};
/*
+ * 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.