From: Oleg Nesterov Date: Tue, 19 Nov 2013 16:20:21 +0000 (+0100) Subject: uprobes: Document xol_area and arch_uprobe->insn/ixol X-Git-Tag: upstream/snapshot3+hdmi~3649^2~24^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ad439356ae5ae7688b39f1107fd5b874850fec18;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git uprobes: Document xol_area and arch_uprobe->insn/ixol Document xol_area and arch_uprobe. Signed-off-by: Oleg Nesterov Acked-by: Srikar Dronamraju --- 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 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.