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Commit 59da2a06 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching 

Pull livepatching updates from Jiri Kosina:

 - removal of dead code (Kamalesh Babulal)

 - documentation update (Miroslav Benes)

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
  livepatch: doc: remove the limitation for schedule() patching
  powerpc/livepatch: Remove klp_write_module_reloc() stub
parents ebb4949e 372e2db7

Documentation/livepatch/livepatch.txt

+0 −19
Original line number Diff line number Diff line
@@ -329,25 +329,6 @@ The current Livepatch implementation has several limitations: 
    by "notrace".





  + Anything inlined into __schedule() can not be patched.



    The switch_to macro is inlined into __schedule(). It switches the

    context between two processes in the middle of the macro. It does

    not save RIP in x86_64 version (contrary to 32-bit version). Instead,

    the currently used __schedule()/switch_to() handles both processes.



    Now, let's have two different tasks. One calls the original

    __schedule(), its registers are stored in a defined order and it

    goes to sleep in the switch_to macro and some other task is restored

    using the original __schedule(). Then there is the second task which

    calls patched__schedule(), it goes to sleep there and the first task

    is picked by the patched__schedule(). Its RSP is restored and now

    the registers should be restored as well. But the order is different

    in the new patched__schedule(), so...



    There is work in progress to remove this limitation.





  + Livepatch modules can not be removed.



    The current implementation just redirects the functions at the very

arch/powerpc/include/asm/livepatch.h

+0 −7
Original line number Diff line number Diff line
@@ -28,13 +28,6 @@ static inline int klp_check_compiler_support(void) 
	return 0;

}



static inline int klp_write_module_reloc(struct module *mod, unsigned long

		type, unsigned long loc, unsigned long value)

{

	/* This requires infrastructure changes; we need the loadinfos. */

	return -ENOSYS;

}



static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)

{

	regs->nip = ip;