ARM: kprobes: Make str_pc_offset a constant on ARMv7
The str_pc_offset value is architecturally defined on ARMv7 onwards so
we can make it a compile time constant. This means on Thumb kernels the
runtime checking code isn't needed, which saves us from having to fix it
to work for Thumb.
Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
diff --git a/arch/arm/kernel/kprobes.h b/arch/arm/kernel/kprobes.h
index 43f630d..406bb2d 100644
--- a/arch/arm/kernel/kprobes.h
+++ b/arch/arm/kernel/kprobes.h
@@ -36,7 +36,21 @@
extern kprobe_check_cc * const kprobe_condition_checks[16];
+
+#if __LINUX_ARM_ARCH__ >= 7
+
+/* str_pc_offset is architecturally defined from ARMv7 onwards */
+#define str_pc_offset 8
+#define find_str_pc_offset()
+
+#else /* __LINUX_ARM_ARCH__ < 7 */
+
+/* We need a run-time check to determine str_pc_offset */
extern int str_pc_offset;
+void __init find_str_pc_offset(void);
+
+#endif
+
/*
* Test if load/store instructions writeback the address register.