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Commit b7e108ee authored by Paul Mundt's avatar Paul Mundt
Browse files

sh: BSS init bugfix and barrier in entry point. 



A synco is needed before we jump to start_kernel().

While we're at it, also move the sh_cpu_init() jump until after
we've zeroed BSS, as this has caused some undesirable results
in sh_cpu_init().

Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 29847622

arch/sh/kernel/head.S

+31 −5
Original line number Diff line number Diff line
@@ -12,6 +12,17 @@ 
 */

#include <linux/linkage.h>



#ifdef CONFIG_CPU_SH4A

#define SYNCO()		synco



#define PREFI(label, reg)	\

	mov.l	label, reg;	\

	prefi	@reg

#else

#define SYNCO()

#define PREFI(label, reg)

#endif



	.section	.empty_zero_page, "aw"

ENTRY(empty_zero_page)

	.long	1		/* MOUNT_ROOT_RDONLY */
@@ -42,6 +53,17 @@ ENTRY(_stext) 
	!			Initialize global interrupt mask

	mov	#0, r0

	ldc	r0, r6_bank



	/*

	 * Prefetch if possible to reduce cache miss penalty.

	 *

	 * We do this early on for SH-4A as a micro-optimization,

	 * as later on we will have speculative execution enabled

	 * and this will become less of an issue.

	 */

	PREFI(5f, r0)

	PREFI(6f, r0)



	!

	mov.l	2f, r0

	mov	r0, r15		! Set initial r15 (stack pointer)
@@ -49,11 +71,7 @@ ENTRY(_stext) 
	shll8	r1		! r1 = 8192

	sub	r1, r0		!

	ldc	r0, r7_bank	! ... and initial thread_info

	!

	!			Additional CPU initialization

	mov.l	6f, r0

	jsr	@r0

	 nop



	!			Clear BSS area

	mov.l	3f, r1

	add	#4, r1
@@ -62,6 +80,14 @@ ENTRY(_stext) 
9:	cmp/hs	r2, r1

	bf/s	9b		! while (r1 < r2)

	 mov.l	r0,@-r2



	!			Additional CPU initialization

	mov.l	6f, r0

	jsr	@r0

	 nop



	SYNCO()			! Wait for pending instructions..



	!			Start kernel

	mov.l	5f, r0

	jmp	@r0