ARM: use r9 for gd

To be more EABI compliant and as a preparation for building
with clang, use the platform-specific r9 register for gd
instead of r8.

note: The FIQ is not updated since it is not used in u-boot,
and under discussion for the time being.

The following checkpatch warning is ignored:
WARNING: Use of volatile is usually wrong: see
Documentation/volatile-considered-harmful.txt

Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
cc: Albert ARIBAUD <albert.u.boot@aribaud.net>

arch/arm/config.mk

@@ -17,7 +17,7 @@ endif
 
 LDFLAGS_FINAL += --gc-sections
 PLATFORM_RELFLAGS += -ffunction-sections -fdata-sections \
-                     -fno-common -ffixed-r8 -msoft-float
+                     -fno-common -ffixed-r9 -msoft-float
 
 # Support generic board on ARM
 __HAVE_ARCH_GENERIC_BOARD := y

arch/arm/cpu/armv7/lowlevel_init.S

@@ -22,11 +22,11 @@ ENTRY(lowlevel_init)
 	ldr	sp, =CONFIG_SYS_INIT_SP_ADDR
 	bic	sp, sp, #7 /* 8-byte alignment for ABI compliance */
 #ifdef CONFIG_SPL_BUILD
-	ldr	r8, =gdata
+	ldr	r9, =gdata
 #else
 	sub	sp, #GD_SIZE
 	bic	sp, sp, #7
-	mov	r8, sp
+	mov	r9, sp
 #endif
 	/*
 	 * Save the old lr(passed in ip) and the current lr to stack

arch/arm/include/asm/global_data.h

@@ -47,6 +47,6 @@ struct arch_global_data {
 
 #include <asm-generic/global_data.h>
 
-#define DECLARE_GLOBAL_DATA_PTR     register volatile gd_t *gd asm ("r8")
+#define DECLARE_GLOBAL_DATA_PTR     register volatile gd_t *gd asm ("r9")
 
 #endif /* __ASM_GBL_DATA_H */

arch/arm/lib/crt0.S

@@ -69,7 +69,7 @@ ENTRY(_main)
 	bic	sp, sp, #7	/* 8-byte alignment for ABI compliance */
 	sub	sp, #GD_SIZE	/* allocate one GD above SP */
 	bic	sp, sp, #7	/* 8-byte alignment for ABI compliance */
-	mov	r8, sp		/* GD is above SP */
+	mov	r9, sp		/* GD is above SP */
 	mov	r0, #0
 	bl	board_init_f
 
@@ -81,15 +81,15 @@ ENTRY(_main)
  * 'here' but relocated.
  */
 
-	ldr	sp, [r8, #GD_START_ADDR_SP]	/* sp = gd->start_addr_sp */
+	ldr	sp, [r9, #GD_START_ADDR_SP]	/* sp = gd->start_addr_sp */
 	bic	sp, sp, #7	/* 8-byte alignment for ABI compliance */
-	ldr	r8, [r8, #GD_BD]		/* r8 = gd->bd */
-	sub	r8, r8, #GD_SIZE		/* new GD is below bd */
+	ldr	r9, [r9, #GD_BD]		/* r9 = gd->bd */
+	sub	r9, r9, #GD_SIZE		/* new GD is below bd */
 
 	adr	lr, here
-	ldr	r0, [r8, #GD_RELOC_OFF]		/* r0 = gd->reloc_off */
+	ldr	r0, [r9, #GD_RELOC_OFF]		/* r0 = gd->reloc_off */
 	add	lr, lr, r0
-	ldr	r0, [r8, #GD_RELOCADDR]		/* r0 = gd->relocaddr */
+	ldr	r0, [r9, #GD_RELOCADDR]		/* r0 = gd->relocaddr */
 	b	relocate_code
 here:
 
@@ -111,8 +111,8 @@ clbss_l:cmp	r0, r1			/* while not at end of BSS */
 	bl red_led_on
 
 	/* call board_init_r(gd_t *id, ulong dest_addr) */
-	mov	r0, r8			/* gd_t */
-	ldr	r1, [r8, #GD_RELOCADDR]	/* dest_addr */
+	mov     r0, r9                  /* gd_t */
+	ldr	r1, [r9, #GD_RELOCADDR]	/* dest_addr */
 	/* call board_init_r */
 	ldr	pc, =board_init_r	/* this is auto-relocated! */