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ftrace: Have the callbacks receive a struct ftrace_regs instead of pt_regs

In preparation to have arguments of a function passed to callbacks attached to functions as default, change the default callback prototype to receive a struct ftrace_regs as the forth parameter instead of a pt_regs. For callbacks that set the FL_SAVE_REGS flag in their ftrace_ops flags, they will now need to get the pt_regs via a ftrace_get_regs() helper call. If this is called by a callback that their ftrace_ops did not have a FL_SAVE_REGS flag set, it that helper function will return NULL. This will allow the ftrace_regs to hold enough just to get the parameters and stack pointer, but without the worry that callbacks may have a pt_regs that is not completely filled.

Steven Rostedt (VMware) committed 6 years ago

Commit d19ad071 parent 58954b318 files · +71 −45Browse files

Showing the changes to kernel/livepatch/patch.c (1 of 18 files). Show all

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kernel/livepatch/patch.c+2−1
@@ -40,8 +40,9 @@ struct klp_ops *klp_find_ops(void *old_func) · 39 unmodified lines
40static void notrace klp_ftrace_handler(unsigned long ip,40static void notrace klp_ftrace_handler(unsigned long ip,
41 unsigned long parent_ip,41 unsigned long parent_ip,
42 struct ftrace_ops *fops,42 struct ftrace_ops *fops,
43 struct pt_regs *regs)43 struct ftrace_regs *fregs)
44{44{
45 struct pt_regs *regs = ftrace_get_regs(fregs);
45 struct klp_ops *ops;46 struct klp_ops *ops;
46 struct klp_func *func;47 struct klp_func *func;
47 int patch_state;48 int patch_state;