Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1268277

[PATCH v3 3/5] x86/asm: Error out if asm/jump_label.h is included inappropriately

Show all headers | View raw

Rather than potentially generating incorrect code on a
non-HAVE_JUMP_LABEL kernel if someone includes asm/jump_label.h,
error out.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 arch/x86/include/asm/jump_label.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
index 5daeca3d0f9e..96872dc96597 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -1,6 +1,19 @@
 #ifndef _ASM_X86_JUMP_LABEL_H
 #define _ASM_X86_JUMP_LABEL_H
 
+#ifndef HAVE_JUMP_LABEL
+/*
+ * For better or for worse, if jump labels (the gcc extension) are missing,
+ * then the entire static branch patching infrastructure is compiled out.
+ * If that happens, the code in here will malfunction.  Raise a compiler
+ * error instead.
+ *
+ * In theory, jump labels and the static branch patching infrastructure
+ * could be decoupled to fix this.
+ */
+#error asm/jump_label.h included on a non-jump-label kernel
+#endif
+
 #ifndef __ASSEMBLY__
 
 #include <linux/stringify.h>
-- 
2.5.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v3 0/5] x86 entry stuff, maybe for 4.4 Andy Lutomirski <luto@kernel.org> - 2015-11-12 22:10 +0100
  [PATCH v3 3/5] x86/asm: Error out if asm/jump_label.h is included inappropriately Andy Lutomirski <luto@kernel.org> - 2015-11-12 22:10 +0100
    Re: [PATCH v3 3/5] x86/asm: Error out if asm/jump_label.h is included  inappropriately Thomas Gleixner <tglx@linutronix.de> - 2015-11-13 15:20 +0100

csiph-web