From: Michael Ellerman <mpe@ellerman.id.au>
Date: Tue, 15 Jul 2014 11:15:37 +0000 (+1000)
Subject: powerpc: Document register clobbering in EXCEPTION_COMMON()
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=a1d711c53f413db330da57bfaf53255a5d62447e;p=linux-beck.git

powerpc: Document register clobbering in EXCEPTION_COMMON()

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index 8f35cd7d59cc..066c15cd2837 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -532,6 +532,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CTRL)
 	.globl label##_common;					\
 label##_common:							\
 	EXCEPTION_PROLOG_COMMON(trap, PACA_EXGEN);		\
+	/* Volatile regs are potentially clobbered here */	\
 	additions;						\
 	addi	r3,r1,STACK_FRAME_OVERHEAD;			\
 	bl	hdlr;						\