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authorStafford Horne <shorne@gmail.com>2017-02-05 18:55:40 +0900
committerStafford Horne <shorne@gmail.com>2017-02-25 05:08:47 +0900
commita4d4426635804379d618dd28e29f574a2bc11184 (patch)
tree38ef4394a132b84ebac0db16ca86d1792311c9da /arch/openrisc/kernel
parenta0eba4f7ebcdf81da0a4480d8fc514af4f76579e (diff)
downloadlinux-a4d4426635804379d618dd28e29f574a2bc11184.tar.bz2
openrisc: head: Init r0 to 0 on start
Originally openrisc spec 0 specified that r0 would be wired to ground. This is no longer the case. r0 is not guaranteed to be 0 at init, so we need to initialize it to 0 before using it. Also, if we are clearing r0 we cant use r0 to clear itself. Change the the CLEAR_GPR macro to use movhi for clearing. Reported-by: Jakob Viketoft <jakob.viketoft@aacmicrotec.com> Signed-off-by: Stafford Horne <shorne@gmail.com>
Diffstat (limited to 'arch/openrisc/kernel')
-rw-r--r--arch/openrisc/kernel/head.S5
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/openrisc/kernel/head.S b/arch/openrisc/kernel/head.S
index fe55156983e0..d01b82eace3e 100644
--- a/arch/openrisc/kernel/head.S
+++ b/arch/openrisc/kernel/head.S
@@ -35,7 +35,7 @@
l.add rd,rd,rs
#define CLEAR_GPR(gpr) \
- l.or gpr,r0,r0
+ l.movhi gpr,0x0
#define LOAD_SYMBOL_2_GPR(gpr,symbol) \
l.movhi gpr,hi(symbol) ;\
@@ -443,6 +443,9 @@ _dispatch_do_ipage_fault:
__HEAD
.global _start
_start:
+ /* Init r0 to zero as per spec */
+ CLEAR_GPR(r0)
+
/* save kernel parameters */
l.or r25,r0,r3 /* pointer to fdt */