kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist

Introduce NOKPROBE_SYMBOL() macro which builds a kprobes
blacklist at kernel build time.

The usage of this macro is similar to EXPORT_SYMBOL(),
placed after the function definition:

  NOKPROBE_SYMBOL(function);

Since this macro will inhibit inlining of static/inline
functions, this patch also introduces a nokprobe_inline macro
for static/inline functions. In this case, we must use
NOKPROBE_SYMBOL() for the inline function caller.

When CONFIG_KPROBES=y, the macro stores the given function
address in the "_kprobe_blacklist" section.

Since the data structures are not fully initialized by the
macro (because there is no "size" information),  those
are re-initialized at boot time by using kallsyms.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/20140417081705.26341.96719.stgit@ltc230.yrl.intra.hitachi.co.jp
Cc: Alok Kataria <akataria@vmware.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christopher Li <sparse@chrisli.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jan-Simon Möller <dl9pf@gmx.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-sparse@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 11 insertions, 0 deletions

diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index 4582e8e1cd1a..7730c1c5c83a 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -57,6 +57,12 @@
         .long (from) - . ;                                      \
         .long (to) - . + 0x7ffffff0 ;                           \
         .popsection
+
+# define _ASM_NOKPROBE(entry)                                   \
+        .pushsection "_kprobe_blacklist","aw" ;                 \
+        _ASM_ALIGN ;                                            \
+        _ASM_PTR (entry);                                       \
+        .popsection
 #else
 # define _ASM_EXTABLE(from,to)                                  \
         " .pushsection \"__ex_table\",\"a\"\n"                  \
@@ -71,6 +77,7 @@
         " .long (" #from ") - .\n"                              \
         " .long (" #to ") - . + 0x7ffffff0\n"                   \
         " .popsection\n"
+/* For C file, we already have NOKPROBE_SYMBOL macro */
 #endif
 
 #endif /* _ASM_X86_ASM_H */
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 1b10af835c31..e136869ae42e 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -23,6 +23,7 @@
 #include <linux/efi.h>
 #include <linux/bcd.h>
 #include <linux/highmem.h>
+#include <linux/kprobes.h>
 
 #include <asm/bug.h>
 #include <asm/paravirt.h>
@@ -389,6 +390,9 @@ __visible struct pv_cpu_ops pv_cpu_ops = {
         .end_context_switch = paravirt_nop,
 };
 
+/* At this point, native_get_debugreg has a real function entry */
+NOKPROBE_SYMBOL(native_get_debugreg);
+
 struct pv_apic_ops pv_apic_ops = {
 #ifdef CONFIG_X86_LOCAL_APIC
         .startup_ipi_hook = paravirt_nop,