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

59da2a06 · Linus Torvalds <[email protected]> · 2017-02-20 17:13:23 -08:00

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

Commit: 59da2a0630b8db5fa71fa5ca0052fd3fe3766d94
Parents: ebb4949e · 372e2db7

Merge commit. Changes below are compared with the first parent: ebb4949e.

Changes

2 files changed · +0 −26

File	Status	Add	Del	Content
Documentation/livepatch/livepatch.txt	modified	+0	−19	View file
arch/powerpc/include/asm/livepatch.h	modified	+0	−7	View file

Documentation/livepatch/livepatch.txt

View file

diff --git a/Documentation/livepatch/livepatch.txt b/Documentation/livepatch/livepatch.txt
index f596731..7f04e13 100644
--- a/Documentation/livepatch/livepatch.txt
+++ b/Documentation/livepatch/livepatch.txt
@@ -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

View file

diff --git a/arch/powerpc/include/asm/livepatch.h b/arch/powerpc/include/asm/livepatch.h
index a402f7f..47a03b9 100644
--- a/arch/powerpc/include/asm/livepatch.h
+++ b/arch/powerpc/include/asm/livepatch.h
@@ -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;