arm: Fix to mistake clean the memory space

In currently, when __bss_start is equal to __bss_end__,
The bss loop will clear all the things in memory space.

But just only when __bss_end__ greater than __bss_start__,
we do the clear bss section operation.

Signed-off-by: Zhong Hongbo <bocui107@gmail.com>
Acked-by: Andreas Bießmann <andreas.devel@googlemail.com>

arch/arm/cpu/arm1136/start.S

@@ -251,10 +251,12 @@ clear_bss:
 	add	r1, r1, r4
 	mov	r2, #0x00000000		/* clear			    */
 
-clbss_l:str	r2, [r0]		/* clear loop...		    */
+clbss_l:cmp	r0, r1			/* clear loop... */
+	bhs	clbss_e			/* if reached end of bss, exit */
+	str	r2, [r0]
 	add	r0, r0, #4
-	cmp	r0, r1
+	b	clbss_l
-	bne	clbss_l
+clbss_e:
 #endif	/* #ifndef CONFIG_SPL_BUILD */
 
 /*

arch/arm/cpu/arm1176/start.S

@@ -351,11 +351,12 @@ clear_bss:
 	add	r1, r1, r4
 	mov	r2, #0x00000000		/* clear			    */
 
-clbss_l:str	r2, [r0]		/* clear loop...		    */
+clbss_l:cmp	r0, r1			/* clear loop... */
+	bhs	clbss_e			/* if reached end of bss, exit */
+	str	r2, [r0]
 	add	r0, r0, #4
-	cmp	r0, r1
+	b	clbss_l
-	bne	clbss_l
+clbss_e:
-
 #ifndef CONFIG_NAND_SPL
 	bl coloured_LED_init
 	bl red_led_on

arch/arm/cpu/arm720t/start.S

@@ -228,10 +228,12 @@ clear_bss:
 	add	r1, r1, r4
 	mov	r2, #0x00000000		/* clear			    */
 
-clbss_l:str	r2, [r0]		/* clear loop...		    */
+clbss_l:cmp	r0, r1			/* clear loop... */
+	bhs	clbss_e			/* if reached end of bss, exit */
+	str	r2, [r0]
 	add	r0, r0, #4
-	cmp	r0, r1
+	b	clbss_l
-	bne	clbss_l
+clbss_e:
 
 	bl coloured_LED_init
 	bl red_led_on

arch/arm/cpu/arm920t/start.S

@@ -271,10 +271,12 @@ clear_bss:
 	add	r1, r1, r4
 	mov	r2, #0x00000000		/* clear			    */
 
-clbss_l:str	r2, [r0]		/* clear loop...		    */
+clbss_l:cmp	r0, r1			/* clear loop... */
+	bhs	clbss_e			/* if reached end of bss, exit */
+	str	r2, [r0]
 	add	r0, r0, #4
-	cmp	r0, r1
+	b	clbss_l
-	bne	clbss_l
+clbss_e:
 
 	bl coloured_LED_init
 	bl red_led_on

arch/arm/cpu/arm925t/start.S

@@ -265,10 +265,12 @@ clear_bss:
 	add	r1, r1, r4
 	mov	r2, #0x00000000		/* clear			    */
 
-clbss_l:str	r2, [r0]		/* clear loop...		    */
+clbss_l:cmp	r0, r1			/* clear loop... */
+	bhs	clbss_e			/* if reached end of bss, exit */
+	str	r2, [r0]
 	add	r0, r0, #4
-	cmp	r0, r1
+	b	clbss_l
-	bne	clbss_l
+clbss_e:
 
 	bl coloured_LED_init
 	bl red_led_on

arch/arm/cpu/arm946es/start.S

@@ -236,10 +236,12 @@ clear_bss:
 	add	r1, r1, r4
 	mov	r2, #0x00000000		/* clear			    */
 
-clbss_l:str	r2, [r0]		/* clear loop...		    */
+clbss_l:cmp	r0, r1			/* clear loop... */
+	bhs	clbss_e			/* if reached end of bss, exit */
+	str	r2, [r0]
 	add	r0, r0, #4
-	cmp	r0, r1
+	b	clbss_l
-	blo	clbss_l
+clbss_e:
 #endif
 
 /*

arch/arm/cpu/arm_intcm/start.S

@@ -232,10 +232,12 @@ clear_bss:
 	add	r1, r1, r4
 	mov	r2, #0x00000000		/* clear			    */
 
-clbss_l:str	r2, [r0]		/* clear loop...		    */
+clbss_l:cmp	r0, r1			/* clear loop... */
+	bhs	clbss_e			/* if reached end of bss, exit */
+	str	r2, [r0]
 	add	r0, r0, #4
-	cmp	r0, r1
+	b	clbss_l
-	bne	clbss_l
+clbss_e:
 
 	bl coloured_LED_init
 	bl red_led_on

arch/arm/cpu/armv7/start.S

@@ -259,10 +259,12 @@ clear_bss:
 #endif
 	mov	r2, #0x00000000		/* clear			    */
 
-clbss_l:str	r2, [r0]		/* clear loop...		    */
+clbss_l:cmp	r0, r1			/* clear loop... */
+	bhs	clbss_e			/* if reached end of bss, exit */
+	str	r2, [r0]
 	add	r0, r0, #4
-	cmp	r0, r1
+	b	clbss_l
-	bne	clbss_l
+clbss_e:
 
 /*
  * We are done. Do not return, instead branch to second part of board

arch/arm/cpu/ixp/start.S

@@ -334,10 +334,12 @@ clear_bss:
 	add	r1, r1, r4
 	mov	r2, #0x00000000		/* clear			    */
 
-clbss_l:str	r2, [r0]		/* clear loop...		    */
+clbss_l:cmp	r0, r1			/* clear loop... */
+	bhs	clbss_e			/* if reached end of bss, exit */
+	str	r2, [r0]
 	add	r0, r0, #4
-	cmp	r0, r1
+	b	clbss_l
-	bne	clbss_l
+clbss_e:
 
 	bl coloured_LED_init
 	bl red_led_on

arch/arm/cpu/lh7a40x/start.S

@@ -245,10 +245,12 @@ clear_bss:
 	add	r1, r1, r4
 	mov	r2, #0x00000000		/* clear			    */
 
-clbss_l:str	r2, [r0]		/* clear loop...		    */
+clbss_l:cmp	r0, r1			/* clear loop... */
+	bhs	clbss_e			/* if reached end of bss, exit */
+	str	r2, [r0]
 	add	r0, r0, #4
-	cmp	r0, r1
+	b	clbss_l
-	bne	clbss_l
+clbss_e:
 #endif
 
 /*

arch/arm/cpu/pxa/start.S

@@ -258,10 +258,12 @@ clear_bss:
 	add	r1, r1, r4
 	mov	r2, #0x00000000		/* clear			    */
 
-clbss_l:str	r2, [r0]		/* clear loop...		    */
+clbss_l:cmp	r0, r1			/* clear loop... */
+	bhs	clbss_e			/* if reached end of bss, exit */
+	str	r2, [r0]
 	add	r0, r0, #4
-	cmp	r0, r1
+	b	clbss_l
-	bne	clbss_l
+clbss_e:
 #endif	/* #ifndef CONFIG_SPL_BUILD */
 
 /*

arch/arm/cpu/s3c44b0/start.S

@@ -217,10 +217,12 @@ clear_bss:
 	add	r1, r1, r4
 	mov	r2, #0x00000000		/* clear			    */
 
-clbss_l:str	r2, [r0]		/* clear loop...		    */
+clbss_l:cmp	r0, r1			/* clear loop... */
+	bhs	clbss_e			/* if reached end of bss, exit */
+	str	r2, [r0]
 	add	r0, r0, #4
-	cmp	r0, r1
+	b	clbss_l
-	bne	clbss_l
+clbss_e:
 
 	bl coloured_LED_init
 	bl red_led_on

arch/arm/cpu/sa1100/start.S

@@ -221,10 +221,12 @@ clear_bss:
 	add	r1, r1, r4
 	mov	r2, #0x00000000		/* clear			    */
 
-clbss_l:str	r2, [r0]		/* clear loop...		    */
+clbss_l:cmp	r0, r1			/* clear loop... */
+	bhs	clbss_e			/* if reached end of bss, exit */
+	str	r2, [r0]
 	add	r0, r0, #4
-	cmp	r0, r1
+	b	clbss_l
-	bne	clbss_l
+clbss_e:
 #endif
 
 /*